Faculty Profiles - TAOKA Toshiaki

Reproducibility of diffusion tensor image analysis along the perivascular space (DTI-ALPS) for evaluating interstitial fluid diffusivity and glymphatic function: CHanges in Alps index on Multiple conditiON acquIsition eXperiment (CHAMONIX) study. Reviewed

Toshiaki Taoka, Rintaro Ito, Rei Nakamichi, Koji Kamagata, Mayuko Sakai, Hisashi Kawai, Toshiki Nakane, Takashi Abe, Kazushige Ichikawa, Junko Kikuta, Shigeki Aoki, Shinji Naganawa

Japanese journal of radiology Vol. 40 ( 2 ) page： 147 - 158 2022.2

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: The diffusion tensor image analysis along the perivascular space (DTI-ALPS) method was developed to evaluate the brain's glymphatic function or interstitial fluid dynamics. This study aimed to evaluate the reproducibility of the DTI-ALPS method and the effect of modifications in the imaging method and data evaluation. MATERIALS AND METHODS: Seven healthy volunteers were enrolled in this study. Image acquisition was performed for this test-retest study using a fixed imaging sequence and modified imaging methods which included the placement of region of interest (ROI), imaging plane, head position, averaging, number of motion-proving gradients, echo time (TE), and a different scanner. The ALPS-index values were evaluated for the change of conditions listed above. RESULTS: This test-retest study by a fixed imaging sequence showed very high reproducibility (intraclass coefficient = 0.828) for the ALPS-index value. The bilateral ROI placement showed higher reproducibility. The number of averaging and the difference of the scanner did not influence the ALPS-index values. However, modification of the imaging plane and head position impaired reproducibility, and the number of motion-proving gradients affected the ALPS-index value. The ALPS-index values from 12-axis DTI and 3-axis diffusion-weighted image (DWI) showed good correlation (r = 0.86). Also, a shorter TE resulted in a larger value of the ALPS-index. CONCLUSION: ALPS index was robust under the fixed imaging method even when different scanners were used. ALPS index was influenced by the imaging plane, the number of motion-proving gradient axes, and TE in the imaging sequence. These factors should be uniformed in the planning ALPS method studies. The possibility to develop a 3-axis DWI-ALPS method using three axes of the motion-proving gradient was also suggested.

DOI： 10.1007/s11604-021-01187-5

Diffusion analysis of fluid dynamics with incremental strength of motion proving gradient (DANDYISM) to evaluate cerebrospinal fluid dynamics Reviewed

Toshiaki Taoka, Hisashi Kawai, Toshiki Nakane, Takashi Abe, Rei Nakamichi, Rintaro Ito, Yuki Sato, Mayuko Sakai, Shinji Naganawa

Japanese Journal of Radiology Vol. 39 ( 4 ) page： 315 - 323 2021.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

<title>Abstract</title><sec>
<title>Purpose</title>
To visualize and analyze the dynamics of cerebrospinal fluid (CSF) motion in the cranium, we evaluated the distribution of motion-related signal dephasing by CSF on Diffusion ANalysis of fluid DYnamics with Incremental Strength of Motion proving gradient (DANDYISM) method, a composite imaging method using various low <italic>b</italic> values.

</sec><sec>
<title>Materials and methods</title>
This study examined ten subjects aged 25–58. We acquired DWIs on a 3T clinical scanner with <italic>b</italic> values 0, 50, 100, 200, 300, 500, 700, and 1000 s/mm2 in total imaging time of 4 min. We constructed DANDYISM images and evaluated the CSF area distribution with decreased motion-dephasing signal using a scoring method.

</sec><sec>
<title>Results</title>
The DANDYISM images showed statistically significant higher CSF scores in the ventral posterior fossa, suprasellar cistern, and Sylvian vallecula compared to the lateral ventricle and frontal and parietal CSF spaces, indicating greater CSF movement in the former areas.

</sec><sec>
<title>Conclusion</title>
The results indicated prominent CSF motions in the ventral portion of the posterior fossa, suprasellar cistern, and Sylvian fissure but smaller motions in the lateral ventricles and parietal subarachnoid space. This method may provide information of CSF dynamics in the clinical settings within short imaging time.

</sec>

DOI： 10.1007/s11604-020-01075-4

Imaging for central nervous system (CNS) interstitial fluidopathy: disorders with impaired interstitial fluid dynamics.

Other Link： http://link.springer.com/article/10.1007/s11604-020-01075-4/fulltext.html

Toshiaki Taoka, Shinji Naganawa

Japanese journal of radiology Vol. 39 ( 1 ) page： 1 - 14 2021.1

Language：English Publishing type：Research paper (scientific journal)

After the introduction of the glymphatic system hypothesis, an increasing number of studies on cerebrospinal fluid and interstitial fluid dynamics within the brain have been investigated and reported. A series of diseases are known which develop due to abnormality of the glymphatic system including Alzheimer's disease, traumatic brain injury, stroke, or other disorders. These diseases or disorders share the characteristics of the glymphatic system dysfunction or other mechanisms related to the interstitial fluid dynamics. In this review article, we propose "Central Nervous System (CNS) Interstitial Fluidopathy" as a new concept encompassing diseases whose pathologies are majorly associated with abnormal interstitial fluid dynamics. Categorizing these diseases or disorders as "CNS interstitial fluidopathies," will promote the understanding of their mechanisms and the development of potential imaging methods for the evaluation of the disease as well as clinical methods for disease treatment or prevention. In other words, having a viewpoint of the dynamics of interstitial fluid appears relevant for understanding CNS diseases or disorders, and it would be possible to develop novel common treatment methods or medications for "CNS interstitial fluidopathies."

DOI： 10.1007/s11604-020-01017-0

Evaluation of glymphatic system activity with the diffusion MR technique: diffusion tensor image analysis along the perivascular space (DTI-ALPS) in Alzheimer's disease cases. Reviewed

Toshiaki Taoka, Yoshitaka Masutani, Hisashi Kawai, Toshiki Nakane, Kiwamu Matsuoka, Fumihiko Yasuno, Toshifumi Kishimoto, Shinji Naganawa

Japanese journal of radiology Vol. 35 ( 4 ) page： 172 - 178 2017.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Nature

PURPOSE: The activity of the glymphatic system is impaired in animal models of Alzheimer's disease (AD). We evaluated the activity of the human glymphatic system in cases of AD with a diffusion-based technique called diffusion tensor image analysis along the perivascular space (DTI-ALPS). MATERIALS AND METHODS: Diffusion tensor images were acquired to calculate diffusivities in the x, y, and z axes of the plane of the lateral ventricle body in 31 patients. We evaluated the diffusivity along the perivascular spaces as well as projection fibers and association fibers separately, to acquire an index for diffusivity along the perivascular space (ALPS-index) and correlated them with the mini mental state examinations (MMSE) score. RESULTS: We found a significant negative correlation between diffusivity along the projection fibers and association fibers. We also observed a significant positive correlation between diffusivity along perivascular spaces shown as ALPS-index and the MMSE score, indicating lower water diffusivity along the perivascular space in relation to AD severity. CONCLUSION: Activity of the glymphatic system may be evaluated with diffusion images. Lower diffusivity along the perivascular space on DTI-APLS seems to reflect impairment of the glymphatic system. This method may be useful for evaluating the activity of the glymphatic system.

DOI： 10.1007/s11604-017-0617-z

Diffusion anisotropy and diffusivity of white matter tracts within the temporal stem in Alzheimer disease: Evaluation of the "tract of interest" by diffusion tensor tractography Reviewed

T Taoka, S Iwasaki, M Sakamoto, H Nakagawa, A Fukusumi, K Myochin, S Hirohashi, T Hoshida, K Kichikawa

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 27 ( 5 ) page： 1040 - 1045 2006.5

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

PURPOSE: Our aim was to determine whether diffusion anisotropy and diffusivity of white matter tracts of the temporal stem in patients with Alzheimer (AD) can be evaluated independently by using diffusion tensor tractography.
MATERIALS AND METHODS: Subjects included 15 patients with AD (11 women and 4 men; mean age, 74 years) and 15 age-matched control subjects (11 women and 4 men; mean age, 72 years). Diffusion tensor images were acquired by using echo-planar imaging. We drew tractographies of the uncinate fasciculus, inferior occipitofrontal fasciculus, and Meyer's loop, with diffusion tensor analysis software. We measured diffusion anisotropy, diffusivity, and the number of voxels along the "tracts of interest" and used the Sludent t test to compare results between patients with AD and controls.
RESULTS: Values of diffusion anisotropy of the bilateral uncinate fasciculus and left inferior occipitofrontal fasciculus were significantly lower for patients with AD than for controls. Also, values of diffusivity in the bilateral uncinate fasciculus were significantly greater for patients with AD than for controls. There was no significant difference in diffusion anisotropy or diffusivity along Meyer's loop between the 2 groups. There was no significant difference in the number of voxels included in all constructed tracts between patients with AD and controls.
CONCLUSION: White matter tracts of the temporal stem can be evaluated independently by using diffusion tensor tractography, which appears to be a promising technique for determining changes in white matter in degenerative diseases.

The Glymphatic System in Humans: Investigations With Magnetic Resonance Imaging. International journal

Shinji Naganawa, Toshiaki Taoka, Rintaro Ito, Mariko Kawamura

Investigative radiology Vol. 59 ( 1 ) page： 1 - 12 2024.1

Language：English Publishing type：Research paper (scientific journal)

The concept of the glymphatic system was proposed more than a decade ago as a mechanism for interstitial fluid flow and waste removal in the central nervous system. The function of the glymphatic system has been shown to be particularly activated during sleep. Dysfunction of the glymphatic system has been implicated in several neurodegenerative diseases. Noninvasive in vivo imaging of the glymphatic system is expected to be useful in elucidating the pathophysiology of these diseases. Currently, magnetic resonance imaging is the most commonly used technique to evaluate the glymphatic system in humans, and a large number of studies have been reported. This review provides a comprehensive overview of investigations of the human glymphatic system function using magnetic resonance imaging. The studies can be divided into 3 categories, including imaging without gadolinium-based contrast agents (GBCAs), imaging with intrathecal administration of GBCAs, and imaging with intravenous administration of GBCAs. The purpose of these studies has been to examine not only the interstitial fluid movement in the brain parenchyma, but also the fluid dynamics in the perivascular and subarachnoid spaces, as well as the parasagittal dura and meningeal lymphatics. Recent research has even extended to include the glymphatic system of the eye and the inner ear. This review serves as an important update and a useful guide for future research directions.

DOI： 10.1097/RLI.0000000000000969

Characteristics of donor vessels and cerebral blood flow in the chronic phase after combined revascularization surgery for moyamoya disease. International journal

Takashi Mamiya, Yoshio Araki, Toshiaki Taoka, Naotoshi Fujita, Kinya Yokoyama, Kenji Uda, Shinsuke Muraoka, Fumiaki Kanamori, Kai Takayanagi, Kazuki Ishii, Masahiro Nishihori, Takashi Izumi, Katsuhiko Kato, Ryuta Saito

Clinical neurology and neurosurgery Vol. 236 page： 108110 - 108110 2024.1

Language：English Publishing type：Research paper (scientific journal)

OBJECTIVE: This study aimed to analyze whether the development of donor vessels after combined revascularization surgery for moyamoya disease (MMD) is related to cerebral blood flow (CBF) changes. METHODS: We retrospectively reviewed the charts of 11 adult (12 hemispheres) and 13 pediatric (19 hemispheres) patients who underwent combined revascularization in our department. The total vessel cross-sectional area (TVA) was the sum of the cross-sectional areas of the superficial temporal, middle meningeal, and deep temporal arteries imaged using time-of-flight magnetic resonance angiography. The ipsilateral relative CBF (RCBF) on the brain surface in the craniotomy area was calculated by single-photon emission computed tomography. ΔTVA and ΔRCBF were defined as the preoperative and postoperative ratios of TVA and RCBF, and their correlations were analyzed in adult and pediatric patients. RESULTS: The TVA and RCBF showed a significant increase after surgery, regardless of the age group. However, there was no significant correlation between ΔTVA and ΔRCBF in either the adult or pediatric groups. While the adult group exhibited significantly higher ΔRCBF values compared to the pediatric group (p < 0.01, r = -0.44), the ΔTVA values were higher in the pediatric group compared to the adult group (p = 0.06). CONCLUSIONS: In the chronic phase after combined revascularization surgery for MMD, the development of measurable TVA of donor vessels does not necessarily correlate with an increase in CBF around the craniotomy area.

DOI： 10.1016/j.clineuro.2023.108110

Assessment of cognitive function and sleep-wake rhythms in community-dwelling older adults

Okuda, M; Noda, A; Iwamoto, K; Hishikawa, N; Miyata, S; Yasuma, F; Taoka, T; Ozaki, N; Suhr, JA; Miyazaki, S

SLEEP AND BIOLOGICAL RHYTHMS Vol. 22 ( 1 ) page： 137 - 145 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Sleep and Biological Rhythms

Disruption of the circadian rhythm and sleep–wake cycles is a consequence of aging and is associated with the cognitive decline and many neurodegenerative conditions. We investigated the bedtime, wake-up time, sleep timing (midpoint between bedtime and wake-up time), and sleep timing standard deviation (SD) using the actigraphy among 80 consecutive volunteers aged ≥ 60 years. Global cognitive function and executive function of detailed cognitive domains were evaluated using the mini-mental state examination (MMSE) and Wisconsin card sorting test (WCST) and subjective daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS). The category achievement (CA), total errors (TE), perseverative errors of Nelson (PEN), non-perseverative errors (NPE), and difficulties in maintaining set (DMS) on the WCST were significantly correlated with sleep timing SD (CA: r = − 0.276, p = 0.013, TE: r = 0.311, p = 0.005, PEN: r = 0.241, p = 0.032, NPE: r = 0.250, p = 0.025, DMS: r = 0.235, p = 0.036), but not with the MMSE score. Multiple regression analyses with the stepwise forward selection method including age, ESS score, bedtime, sleep timing, and sleep timing SD, revealed that the ESS score, and sleep timing SD were significant factors related to CA on the WCST (ESS score: β = − 0.322, p = 0.004; sleep timing SD: β = − 0.250, p = 0.022). Assessment of sleep–wake rhythms, daytime sleepiness, and cognitive function using the MMSE and WCST is valuable for the prediction of cognitive decline in the geriatric population.

DOI： 10.1007/s41105-023-00491-z

Glymphatic System Dysfunction in Myelin Oligodendrocyte Glycoprotein Immunoglobulin G Antibody?Associated Disorders: Association with Clinical Disability Reviewed

Hagiwara, A; Tomizawa, Y; Hoshino, Y; Yokoyama, K; Kamagata, K; Sekine, T; Takabayashi, K; Nakaya, M; Maekawa, T; Akashi, T; Wada, A; Taoka, T; Naganawa, S; Hattori, N; Aoki, S

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 45 ( 1 ) page： 66 - 71 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：American Journal of Neuroradiology

BACKGROUND AND PURPOSE: Impaired glymphatic function has been suggested to be implicated in the pathophysiology of MS and aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder. This study aimed to investigate the interstitial fluid dynamics in the brain in patients with myelin oligodendrocyte glycoprotein antibody disorders (MOGAD), another demyelinating disorder, using a noninvasive imaging technique called the diffusivity along the perivascular space (ALPS) index. MATERIALS AND METHODS: A prospective study was conducted on 16 patients with MOGAD in remission and 22 age- and sexmatched healthy control subjects. MR imaging was performed using a 3T scanner, and the ALPS index was calculated using diffusion MR imaging data with a b-value of 1000 s/mm2. The ALPS index and gray matter volumes were compared between the 2 groups, and these parameters were correlated with the Expanded Disability Status Scale. RESULTS: The mean ALPS index of patients with MOGAD was significantly lower than that of healthy controls (Cohen d 0.93, false discovery rate-corrected P .02). The lower mean ALPS index was significantly associated with a worse Expanded Disability Status Scale score (Spearman r _0.51; 95% CI, _0.85 to _0.02; P .03). However, cortical volume and deep gray matter volume were not significantly different between the 2 groups, and they were not correlated with the Expanded Disability Status Scale. CONCLUSIONS: This study suggests that patients with MOGAD may have impaired glymphatic function, as measured by the ALPS index, which is associated with patient disability. Further study is warranted with a larger sample size.

DOI： 10.3174/ajnr.A8066

Assessing interstitial fluid dynamics in type 2 diabetes mellitus and prediabetes cases through diffusion tensor imaging analysis along the perivascular space. Reviewed

Assessing the Real-World, Long-Term Impact of Lemborexant on Sleep Quality in a Home-Based Clinical Study.

Miyata S, Iwamoto K, Okada I, Fujimoto A, Kogo Y, Mori D, Amano M, Matsuyama N, Nishida K, Ando M, Taoka T, Naganawa S, Ozaki N

Nature and science of sleep Vol. 16 page： 291 - 303 2024

Tuerxun R, Kamagata K, Saito Y, Andica C, Takabayashi K, Uchida W, Yoshida S, Kikuta J, Tabata H, Naito H, Someya Y, Kaga H, Miyata M, Akashi T, Wada A, Taoka T, Naganawa S, Tamura Y, Watada H, Kawamori R, Aoki S

Frontiers in aging neuroscience Vol. 16 page： 1362457 2024

Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers in Aging Neuroscience

Background and purpose: Glymphatic system in type 2 diabetes mellitus (T2DM) but not in the prodrome, prediabetes (Pre-DM) was investigated using diffusion tensor image analysis along the perivascular space (DTI-ALPS). Association between glymphatic system and insulin resistance of prominent characteristic in T2DM and Pre-DM between is yet elucidated. Therefore, this study delves into the interstitial fluid dynamics using the DTI-ALPS in both Pre-DM and T2DM and association with insulin resistance. Materials and methods: In our cross-sectional study, we assessed 70 elderly individuals from the Bunkyo Health Study, which included 22 with Pre-DM, 18 with T2DM, and 33 healthy controls with normal glucose metabolism (NGM). We utilized the general linear model (GLM) to evaluate the ALPS index based on DTI-ALPS across these groups, considering variables like sex, age, intracranial volume, years of education, anamnesis of hypertension and hyperlipidemia, and the total Fazekas scale. Furthermore, we have explored the relationship between the ALPS index and insulin resistance, as measured by the homeostasis model assessment of insulin resistance (HOMA-IR) using GLM and the same set of covariates. Results: In the T2DM group, the ALPS index demonstrated a reduction compared with the NGM group [family-wise error (FWE)-corrected p < 0.001; Cohen's d = −1.32]. Similarly, the Pre-DM group had a lower ALPS index than the NGM group (FWE-corrected p < 0.001; Cohen's d = −1.04). However, there was no significant disparity between the T2DM and Pre-DM groups (FWE-corrected p = 1.00; Cohen's d = −0.63). A negative correlation was observed between the ALPS index and HOMA-IR in the combined T2DM and Pre-DM groups (partial correlation coefficient r = −0.35, p < 0.005). Conclusion: The ALPS index significantly decreased in both the pre-DM and T2DM groups and showed a correlated with insulin resistance. This indicated that changes in interstitial fluid dynamics are associated with insulin resistance.

DOI： 10.3389/fnagi.2024.1362457

Glymphatic system impairment in sleep disruption: diffusion tensor image analysis along the perivascular space (DTI-ALPS). Reviewed

Yuya Saito, Yayoi Hayakawa, Koji Kamagata, Junko Kikuta, Takeshi Mita, Christina Andica, Toshiaki Taoka, Wataru Uchida, Kaito Takabayashi, Rukeye Tuerxun, Zaimire Mahemuti, Seina Yoshida, Takafumi Kitagawa, Takashi Arai, Akiyoshi Suzuki, Kanako Sato, Mitsuo Nishizawa, Toshiaki Akashi, Keigo Shimoji, Akihiko Wada, Shigeki Aoki

Japanese journal of radiology Vol. 41 ( 12 ) page： 1335 - 1343 2023.12

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: This study aimed to evaluate the relationship between sleep quality as assessed using the Pittsburgh Sleep Quality Index (PSQI) and the index of diffusivity along the perivascular space (ALPS index), a possible indirect indicator of glymphatic system activity. MATERIALS AND METHODS: This study included the diffusion magnetic resonance imaging (MRI) data of 317 people with sleep disruption and 515 healthy controls (HCs) from the Human Connectome Project (WU-MINN HCP 1200). The ALPS index was calculated automatically based on diffusion tensor image analysis (DTI)-ALPS of diffusion MRI. The ALPS index of the sleep disruption and HC groups was compared using general linear model (GLM) analysis with covariates, such as age, sex, level of education, and intracranial volume. In addition, to confirm the relationship between sleep quality and the ALPS index in the sleep disruption group as well as evaluate the effect of each PSQI component on the ALPS index, correlation analyses between the ALPS indices and PSQI scores of all the components and between the ALPS index and each PSQI component was performed using GLM analysis with the abovementioned covariates, respectively. RESULTS: The ALPS index was significantly lower in the sleep disruption group than in the HC group (p = 0.001). Moreover, the ALPS indices showed significant negative correlations with the PSQI scores of all the components (false discovery rate [FDR]-corrected p < 0.001). Two significant negative correlations were also found between the ALPS index and PSQI component 2 (sleep latency, FDR-corrected p < 0.001) and 6 (the use of sleep medication, FDR-corrected p < 0.001). CONCLUSION: Our findings suggest that glymphatic system impairment contributes to sleep disruption in young adults.

DOI： 10.1007/s11604-023-01463-6

Higher longitudinal brain white matter atrophy rate in aquaporin-4 IgG-positive NMOSD compared with healthy controls Reviewed

Masuda H., Mori M., Hirano S., Uzawa A., Uchida T., Muto M., Ohtani R., Aoki R., Hirano Y., Iwatsubo T., Asada T., Arai H., Sugishita M., Matsuda H., Ito K., Senda M., Ishii K., Kuwano R., Ikeuchi T., Sato N., Sato H., Shimohama S., Saitoh M., Yamauchi R., Hayashi T., Kobayashi S., Nakano N., Kanazawa J., Ando T., Takanami C., Hareyama M., Hatakenaka M., Tsukamoto E., Ochi S., Shoji M., Matsubara E., Kawarabayashi T., Wakasaya Y., Nakata T., Nakahata N., Ono S., Takai Y., Takahashi S., Yonezawa H., Takahashi J., Kudoh M., Sasaki M., Matsumura Y., Hirata Y., Metoki T., Hayakawa S., Sato Y., Takeda M., Sasaki T., Sera K., Terasaki K., Saitoh Y., Goto S., Ueno K., Sakashita H., Watanabe K., Nagata K., Sato Y., Maeda T., Kondoh Y., Yamazaki T., Takano D., Miyata M., Komatsu H., Watanabe M., Sinoda T., Muraoka R., Kikuchi K., Ito H., Sato A., Kinoshita T., Toyoshima H., Sato K., Sugawara S., Ito I., Kumagai F., Furukawa K., Waragai M., Tomita N., Okamura N., Ootsuki M., Sugawara K., Sugawara S., Mugikura S., Umetsu A., Murata T., Nagasaka T., Kudo Y., Tashiro M., Watanuki S., Nishizawa M., Tokutake T., Ishikawa S., Kishida E., Sato N.

Scientific Reports Vol. 13 ( 1 ) 2023.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Scientific Reports

We aimed to compare longitudinal brain atrophy in patients with neuromyelitis optica spectrum disorder (NMOSD) with healthy controls (HCs). The atrophy rate in patients with anti-aquaporin-4 antibody-positive NMOSD (AQP4 + NMOSD) was compared with age-sex-matched HCs recruited from the Japanese Alzheimer’s Disease Neuroimaging Initiative study and another study performed at Chiba University. Twenty-nine patients with AQP4 + NMOSD and 29 HCs were enrolled in the study. The time between magnetic resonance imaging (MRI) scans was longer in the AQP4 + NMOSD group compared with the HCs (median; 3.2 vs. 2.9 years, P = 0.009). The annualized normalized white matter volume (NWV) atrophy rate was higher in the AQP4 + NMOSD group compared with the HCs (median; 0.37 vs. − 0.14, P = 0.018). The maximum spinal cord lesion length negatively correlated with NWV at baseline MRI in patients with AQP4 + NMOSD (Spearman’s rho = − 0.41, P = 0.027). The annualized NWV atrophy rate negatively correlated with the time between initiation of persistent prednisolone usage and baseline MRI in patients with AQP4 + NMOSD (Spearman’s rho = − 0.43, P = 0.019). Patients with AQP4 + NMOSD had a greater annualized NWV atrophy rate than HCs. Suppressing disease activity may prevent brain atrophy in patients with AQP4 + NMOSD.

DOI： 10.1038/s41598-023-38893-1

Intracranial Air Absorption through Arachnoid Granulation: New Considerations from Transsphenoidal Surgery and Implications for Neurofluid Dynamics

Naganawa Shinji, Ito Rintaro, Kawamura Mariko, Taoka Toshiaki

Magnetic Resonance in Medical Sciences Vol. advpub ( 0 ) 2023.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

Postsurgery intracranial air usually diminishes, presumably merging with cerebrospinal fluid (CSF) and venous circulation. Our study presents two transsphenoidal surgery cases, highlighting potential air absorption by arachnoid granulation (AG)—an underexplored phenomenon. AG has long been deemed pivotal for CSF absorption, but recent perspectives suggest a significant role in waste clearance, neuroinflammation, and neuroimmunity. These cases may stimulate renewed research on the multifaceted role of AG in neurofluid dynamics and potentially elucidate further AG functions.

DOI： 10.2463/mrms.bc.2023-0122

Multisite harmonization of diffusion tensor image analysis along the perivascular space using the COMBined Association Test. Reviewed

Diffusivity Along the Perivascular Space is Decreased and Related to Hypoperfusion in Adult Moyamoya disease

Shoko Hara, Junko Kikuta, Kaito Takabayashi, Koji Kamagata, Shihori Hayashi, Motoki Inaji, Yoji Tanaka, Masaaki Hori, Kenji Ishii, Tadashi Nariai, Toshiaki Taoka, Shinji Naganawa, Shigeki Aoki, Taketoshi Maehara

2023.10

Yuya Saito, Koji Kamagata, Christina Andica, Toshiaki Taoka, Rukeye Tuerxun, Wataru Uchida, Kaito Takabayashi, Mana Owaki, Seina Yoshida, Keigo Yamazaki, Shinji Naganawa, Shigeki Aoki

Japanese journal of radiology Vol. 41 ( 10 ) page： 1072 - 1083 2023.10

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: This multisite study aimed to use the COMBined Association Test (COMBAT), a harmonization technique that uses regression of covariates with an empirical Bayesian framework, to harmonize diffusion tensor image analysis along the perivascular space (DTI-ALPS) variations caused by scanner, site, and protocol differences. MATERIALS AND METHODS: This study included multisite diffusion magnetic resonance imaging (dMRI) data of 45 patients with Alzheimer's disease (AD) and 82 cognitively normal (CN) participants from the AD neuroimaging initiative database. The dMRI data were obtained with two b values (0 and 1000 s/mm2) from 27 institutions and three different 3-Tesla MRI scanners (two vendors). The ALPS index was calculated from multisite dMRI data, and COMBAT was used to harmonize the factors causing site variations. Welch's t test was used, Cohen's d was calculated to compare the difference in the ALPS index between AD and CN before and after harmonization, and Pearson's correlation coefficient was calculated to assess the relationships between the ALPS index and the cognitive score, [18F] fluorodeoxyglucose (FDG)-positron emission tomography (PET), and [18F] florbetapir (AV45)-PET standardized uptake value ratios (SUVRs). RESULTS: COMBAT harmonized scanner differences and increased Cohen's d of the left and right ALPS indexes between AD and CN from 0.288 to 0.438 and 0.328 to 0.480, respectively. The ALPS indexes were significantly different between AD and CN after harmonization (P < 0.05) but not before it. Moreover, Pearson's correlation coefficients between the ALPS index and cognitive score, FDG-PET, and AV45-PET SUVRs were higher after harmonization than before it. CONCLUSION: This study demonstrates the application of COMBAT harmonization to eliminate between-scanner, site, and protocol variations in the ALPS index calculated from DTI-ALPS using dMRI and possibly facilitate the use of the ALPS index in multi-center studies.

DOI： 10.1007/s11604-023-01432-z

Evaluation of alterations in interstitial fluid dynamics in cases of whole-brain radiation using the diffusion-weighted image analysis along the perivascular space method. Invited Reviewed International journal

Toshiaki Taoka, Rintaro Ito, Rei Nakamichi, Toshiki Nakane, Mariko Kawamura, Shunichi Ishihara, Kazushige Ichikawa, Hisashi Kawai, Shinji Naganawa

NMR in biomedicine page： e5030 2023.9

Language：English Publishing type：Research paper (scientific journal)

In the current study, we assessed changes in interstitial fluid dynamics resulting after whole-brain radiotherapy using the diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, which is a simplified variation of the diffusion tensor image ALPS (DTI-ALPS) method using diffusion-weighted imaging (DWI) with orthogonal motion-probing gradients (MPGs). This retrospective study included 47 image sets from 22 patients who underwent whole-brain radiotherapy for brain tumors. The data for the normal control group comprised 105 image sets from 105 participants with no pathological changes. DWI was performed with the three MPGs applied in an orthogonal direction to the imaging plane, and apparent diffusion coefficient images for the x-, y-, and z-axes were retrospectively generated. The ALPS index was calculated to quantify interstitial fluid dynamics. The independent t-test was used to compare the ALPS index between normal controls and patients who underwent whole-brain radiotherapy. Patients were compared in all age groups and individual age groups (20-39, 40-59, and 60-84 years). We also examined the correlation between biologically equivalent doses (BEDs) and the ALPS index, as well as the correlation between white matter hyperintensity and the ALPS index. In the comparison of all age groups, the ALPS index was significantly lower (p < 0.001) in the postradiation group (1.32 ± 0.16) than in the control group (1.44 ± 0.17), suggesting that interstitial fluid dynamics were altered in patients following whole-brain radiotherapy. Significant age group differences were found (40-59 years: p < 0.01; 60-84 years: p < 0.001), along with a weak negative correlation between BEDs (r = -0.19) and significant correlations between white matter hyperintensity and the ALPS index (r = -0.46 for periventricular white matter, r = -0.38 for deep white matter). It was concluded that the ALPS method using DWI with orthogonal MPGs suggest alteration in interstitial fluid dynamics in patients after whole-brain radiotherapy. Further systematic prospective studies are required to investigate their association with cognitive symptoms.

DOI： 10.1002/nbm.5030

In reply: the improvement technique for reproducibility of diffusion tensor image analysis along the perivascular space (DTI-ALPS) for evaluating interstitial fluid diffusivity and glymphatic function.

Toshiaki Taoka

Japanese journal of radiology Vol. 41 ( 9 ) page： 1031 - 1032 2023.9

From pituitary adenoma to PitNET: it is time to discuss PitNET/pituitary adenoma.

Yasutaka Fushimi, Toshiaki Taoka, Shinji Naganawa

Japanese journal of radiology Vol. 41 ( 8 ) page： 787 - 788 2023.8

Emerging Perspectives on MRI Application in Multiple Sclerosis: Moving from Pathophysiology to Clinical Practice. Reviewed International journal

Maria Assunta Rocca, Monica Margoni, Marco Battaglini, Arman Eshaghi, Jeffrey Iliff, Elisabetta Pagani, Paolo Preziosa, Loredana Storelli, Toshiaki Taoka, Paola Valsasina, Massimo Filippi

Radiology Vol. 307 ( 5 ) page： e221512 2023.6

Language：English Publishing type：Research paper (scientific journal)

MRI plays a central role in the diagnosis of multiple sclerosis (MS) and in the monitoring of disease course and treatment response. Advanced MRI techniques have shed light on MS biology and facilitated the search for neuroimaging markers that may be applicable in clinical practice. MRI has led to improvements in the accuracy of MS diagnosis and a deeper understanding of disease progression. This has also resulted in a plethora of potential MRI markers, the importance and validity of which remain to be proven. Here, five recent emerging perspectives arising from the use of MRI in MS, from pathophysiology to clinical application, will be discussed. These are the feasibility of noninvasive MRI-based approaches to measure glymphatic function and its impairment; T1-weighted to T2-weighted intensity ratio to quantify myelin content; classification of MS phenotypes based on their MRI features rather than on their clinical features; clinical relevance of gray matter atrophy versus white matter atrophy; and time-varying versus static resting-state functional connectivity in evaluating brain functional organization. These topics are critically discussed, which may guide future applications in the field.

DOI： 10.1148/radiol.221512

ALPS-indexを用いた糖尿病と糖尿病前期の病態におけるGlymphatic systemの評価［大会長賞記録］

鎌形康司, 内田航, 斎藤勇哉, 高林海斗, 加賀英義, 染谷由希, 明石敏昭, 和田昭彦, 田端宏樹, 内藤仁嗣, 田村好史, 田岡俊昭, 長縄慎二, 河盛隆造, 綿田裕孝, 青木茂樹

日本磁気共鳴医学会雑誌 Vol. 43 ( 2 ) page： 60 - 62 2023.5

Glymphatic System Activity May Be Disrupted in Moyamoya Disease : The Diffusion Tensor Image Analysis Along the Perivascular Space (DTI-ALPS) Study [Presidential Award Proceedings]

HARA Shoko, KIKUTA Junko, TAKABAYASHI Kaito, KAMAGATA Koji, HAYASHI Shihori, INAJI Motoki, TANAKA Yoji, HORI Masaaki, ISHII Kenji, NARIAI Tadashi, TAOKA Toshiaki, NAGANAWA Shinji, AOKI Shigeki, MAEHARA Taketoshi

Japanese Journal of Magnetic Resonance in Medicine Vol. 43 ( 2 ) page： 56 - 59 2023.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

This study aimed to investigate diffusion along the perivascular space (DTI-ALPS index), which may reflect glymphatic system function in adult patients with moyamoya disease. We evaluated 46 patients with moyamoya disease using multishell diffusion magnetic resonance imaging, perfusion parameters of 15O-gas positron emission tomography, and cognitive tests. Diffusion data were analyzed to evaluate the DTI-ALPS index and free water parameters of each hemisphere and compared with the DTI-ALPS index of 34 age-sex-matched normal controls. Compared to normal controls, patients with moyamoya disease showed a significantly lower DTI-ALPS index (mean (standard deviation)=1.93 (0.25) vs. 1.64 (0.22) ; p<0.001). The DTI-ALPS index of patients with moyamoya disease was significantly correlated with perfusion parameters (vs. mean transit time, r=0.33), free water parameters (vs. free water fraction created from free water eliminated diffusion tensor imaging of the cortex, r=−0.24), and executive function (vs. trail making test part B, r=−0.47). These results indicate that glymphatic system dysfunction may exist, correlate with the degree of hemodynamic disturbance, lead to increased parenchymal free water, and be related to cognitive dysfunction in adult patients with moyamoya disease.

DOI： 10.2463/jjmrm.2022-1774

Neuroimaging uncovers distinct relationships of glymphatic dysfunction and motor symptoms in Parkinson's disease. International journal

Yan Qin, Runcheng He, Juan Chen, Xiaoxia Zhou, Xun Zhou, Zhenhua Liu, Qian Xu, Ji-Feng Guo, Xin-Xiang Yan, Nana Jiang, Weihua Liao, Toshiaki Taoka, Dongcui Wang, Beisha Tang

Journal of neurology Vol. 270 ( 5 ) page： 2649 - 2658 2023.5

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Studies of glymphatic dysfunction in Parkinson's disease (PD) patients have attracted much attention in recent years. However, the relationships between glymphatic dysfunction and clinical symptoms remains unclear. OBJECTIVES: To determine whether the diffusion tensor image analysis along the perivascular space (DTI-ALPS) affect the severity and types of motor and non-motor symptoms in PD patients. METHODS: De novo PD patients and controls who performed both DTI and 123I-DaTscan single photon emission computed tomography (SPECT) scanning were retrieved from the international multicenter Parkinson's Progression Marker Initiative (PPMI) cohort. Glymphatic system was evaluated by the DTI-ALPS. Motor symptoms were assessed by Movement Disorders Society Unified Parkinson's Disease Rating Scale III (MDS-UPDRS-III). The influence of glymphatic activity on motor and non-motor symptoms was explored by multivariate linear regression models. RESULTS: A total of 153 PD patients (mean age 60.97 ± 9.47 years; 99 male) and 67 normal controls (mean age 60.10 ± 10.562 years; 43 male) were included. The DTI-ALPS index of PD patients was significantly lower than normal controls (Z = - 2.160, p = 0.031). MDS-UPDRS III score (r = - 0.213, p = 0.008) and subscore for rigidity (r = - 0.177, p = 0.029) were negatively correlated with DTI-ALPS index. The DTI-ALPS index was significantly associated with MDS-UPDRS-III score (β = - 0.160, p = 0.048) and subscore for rigidity (β = - 0.170, p = 0.041) after adjusting for putamen dopamine transporter availability and clinical factors. CONCLUSIONS: Our results showed distinct relationships between glymphatic dysfunction and the severity and types of PD motor symptoms, suggesting the potential of DTI-ALPS index as a biomarker for PD motor symptoms.

DOI： 10.1007/s00415-023-11594-5

もやもや病にGlymphatic system機能不全は存在するか? DTI-ALPS indexによる評価

原祥子, 菊田潤子, 高林海斗, 鎌形康司, 林志保里, 稲次基希, 田中洋次, 堀正明, 石井賢二, 成相直, 田岡俊昭, 長縄慎二, 青木茂樹, 前原健寿

日本磁気共鳴医学会雑誌 Vol. 43 ( 2 ) page： 56 - 59 2023.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：(一社)日本磁気共鳴医学会

もやもや病のGlymphatic system(GS)について、DTI analysis along the perivascular space(DTI-ALPS index)を用いて検討した。成人もやもや病患者46名(男性13名、女性33名、平均38.4歳)と年齢、性別の合致した健常人34名(男性7名、女性27名、平均40.1歳)を対象とし、3T機でEPIシーケンスによる拡散MRIとMPRAGE法による3DT1強調像を撮影した。患者全例で認知機能検査としてTrail Making Test(TMT)を行った。もやもや病のDTI-ALPS indexは健常人より有意に低く、脳実質水成分と負の相関を示した。DTI-ALPS indexはPETのパラメータのうち、脳灌流圧の逆波である平均通過時間(MTT)と有意な負の相関を示した。遂行機能障害が強いほど点数が高くなるTMT-Bは左半球のDTI-ALPS indexと有意な負の相関を示した。もやもや病では脳循環不全の程度に応じてGS機能不全が存在し、脳実質の水成分増加を生じ、認知機能障害と関連する可能性があると考えられた。

特集臨床MRIを基礎から知る−さまざまな角度からMRIの魅力に迫る− [頭部領域] 頭部外傷

田岡俊昭

臨床画像 Vol. 39 ( 13 ) page： 40 - 45 2023.4

Glymphatic system impairment in nonathlete older male adults who played contact sports in their youth associated with cognitive decline: A diffusion tensor image analysis along the perivascular space study Reviewed International journal

Yuichi Morita, Koji Kamagata, Christina Andica, Kaito Takabayashi, Junko Kikuta, Shohei Fujita, Thomas Samoyeau, Wataru Uchida, Yuya Saito, Hiroki Tabata, Hitoshi Naito, Yuki Someya, Hideyoshi Kaga, Yoshifumi Tamura, Mari Miyata, Toshiaki Akashi, Akihiko Wada, Toshiaki Taoka, Shinji Naganawa, Hirotaka Watada, Ryuzo Kawamori, Osamu Abe, Shigeki Aoki

Frontiers in Neurology Vol. 14 page： 1100736 - 1100736 2023.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers Media SA

Background and purpose

Exposure to contact sports in youth causes brain health problems later in life. For instance, the repetitive head impacts in contact sports might contribute to glymphatic clearance impairment and cognitive decline. This study aimed to assess the effect of contact sports participation in youth on glymphatic function in old age and the relationship between glymphatic function and cognitive status using the analysis along the perivascular space (ALPS) index.

Materials and methods

A total of 52 Japanese older male subjects were included in the study, including 12 who played heavy-contact sports (mean age, 71.2 years), 15 who played semicontact sports (mean age, 73.1 years), and 25 who played noncontact sports (mean age, 71.3 years) in their youth. All brain diffusion-weighted images (DWIs) of the subjects were acquired using a 3T MRI scanner. The ALPS indices were calculated using a validated semiautomated pipeline. The ALPS indices from the left and right hemispheres were compared between groups using a general linear model, including age and years of education. Furthermore, partial Spearman's rank correlation tests were performed to assess the correlation between the ALPS indices and cognitive scores (Mini-Mental State Examination and the Japanese version of the Montreal Cognitive Assessment [MoCA-J]) after adjusting for age years of education and HbA1c.

Results

The left ALPS index was significantly lower in the heavy-contact and semicontact groups than that in the noncontact group. Although no significant differences were observed in the left ALPS index between the heavy-contact and semicontact groups and in the right ALPS index among groups, a trend toward lower was found in the right ALPS index in individuals with semicontact and heavy-contact compared to the noncontact group. Both sides' ALPS indices were significantly positively correlated with the MoCA-J scores.

Conclusion

The findings indicated the potential adverse effect of contact sports experience in youth on the glymphatic system function in old age associated with cognitive decline.

DOI： 10.3389/fneur.2023.1100736

Neuroimaging findings related to glymphatic system alterations in older adults with metabolic syndrome. International journal

Christina Andica, Koji Kamagata, Kaito Takabayashi, Junko Kikuta, Hideyoshi Kaga, Yuki Someya, Yoshifumi Tamura, Ryuzo Kawamori, Hirotaka Watada, Toshiaki Taoka, Shinji Naganawa, Shigeki Aoki

Neurobiology of disease Vol. 177 page： 105990 - 105990 2023.2

Language：English Publishing type：Research paper (scientific journal)

OBJECTIVE: The glymphatic system is a glial-based perivascular network that promotes brain metabolic waste clearance. Reduced glymphatic flow has been observed in rat models of type 2 diabetes and hypertension, indicating the role of vascular risk factors in the glymphatic system. However, little is known about how vascular risk factors affect the human glymphatic system. The present study aims to assess the relationships between metabolic syndrome (MetS), a cluster of vascular risk factors, and the glymphatic system function using diffusion magnetic resonance imaging (MRI)-based measures of water diffusivity in the glymphatic compartments, including the brain interstitial space and perivascular spaces around the deep medullary vein. We hypothesized that vascular risk factors are associated with glymphatic dysfunction, leading to cognitive impairment in older adults. METHODS: This cross-sectional study assessed 61 older adults (age range, 65-82 years) who had participated in the Bunkyo Health Study, including 15 healthy controls (mean age, 70.87 ± 4.90 years) and 46 individuals with MetS (mean age, 71.76 ± 4.61 years). Fractional volume of extracellular-free water (FW) and an index of diffusion tensor imaging along the perivascular space (DTI-ALPS) were used as indirect indicators of water diffusivity in the interstitial extracellular and perivenous spaces of white matter, respectively. RESULTS: After adjusting for age, sex, years of education, total Fazekas scale, Pittsburgh sleep quality index (PSQI) score, and intracranial volume (ICV), a significantly (P = 0.030; Cohen's d = 1.01) higher FW was observed in individuals with MetS than in the healthy controls. Furthermore, individuals with MetS had a significantly (P = 0.031; Cohen's d = 0.86) lower ALPS index than the healthy controls, with age, sex, years of education, total Fazekas scale, PSQI score, ICV, fractional anisotropy, and mean diffusivity included as confounding factors. Higher FW was significantly associated with lower ALPS index (r = -0.37; P = 0.004). Multiple linear regression (MLR) with backward elimination analyses showed that higher diastolic blood pressure (BP; standardized β = 0.33, P = 0.005) was independently associated with higher FW, whereas higher fasting plasma glucose levels (standardized β = -0.63, P = 0.002) or higher Brinkman index of cigarette consumption cumulative amount (standardized β = -0.27, P = 0.022) were associated with lower ALPS index. The lower ALPS index (standardized β, 0.28; P = 0.040) was associated with poorer global cognitive performance, which was determined using the Japanese version of the Montreal Cognitive Assessment (MOCA-J) scores. Finally, partial correlation analyses showed a significant correlation between higher FW and lower MOCA-J scores (r = -0.35; P = 0.025) and between higher FW and higher diastolic BP (r = 0.32, P = 0.044). CONCLUSION: The present study shows the changes in diffusion MRI-based measures reflected by the higher FW and lower ALPS index in older adults with MetS, possibly due to the adverse effect of vascular risk factors on the glymphatic system. Our findings also indicate the associations between the diffusion MRI-based measures and elevated diastolic BP, hyperglycemia, smoking habit, and poorer cognitive performance. However, owing to the limitations of this study, the results should be cautiously interpreted.

DOI： 10.1016/j.nbd.2023.105990

Association between the Putative Meningeal Lymphatics at the Posterior Wall of the Sigmoid Sinus and Delayed Contrast-agent Elimination from the Cerebrospinal Fluid.

Shinji Naganawa, Rintaro Ito, Mariko Kawamura, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 23 ( 1 ) page： 80 - 91 2023.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: To investigate the characteristics of the putative meningeal lymphatics located at the posterior wall of the sigmoid sinus (PML-PSS) in human subjects imaged before and after intravenous administration (IV) of a gadolinium-based contrast agent (GBCA). The appearance of the PML-PSS and the enhancement of the perivascular space of the basal ganglia (PVS-BG) were analyzed for an association with gender, age, and clearance of the GBCA from the cerebrospinal fluid (CSF). METHODS: Forty-two patients with suspected endolymphatic hydrops were included. Heavily T2-weighted 3D-fluid attenuated inversion recovery (hT2w-3D-FLAIR) and 3D-real inversion recovery (IR) images were obtained at pre-administration, immediately post-administration, and at 4 and 24 hours after IV-GBCA. The appearance of the PML-PSS and the presence of enhancement in the PVS-BG were analyzed for a relationship with age, gender, contrast enhancement of the CSF at 4 hours after IV-GBCA, and the washout ratio of the GBCA in the CSF from 4 to 24 hours after IV-GBCA. RESULTS: The PML-PSS and PVS-BG were seen in 23 of 42 and 21 of 42 cases, respectively, at 4 hours after IV-GBCA. In all PML-PSS positive cases, hT2w-3D-FLAIR signal enhancement was highest at 4 hours after IV-GBCA. A multivariate analysis between gender, age, CSF signal elevation at 4 hours, and washout ratio indicated that only the washout ratio was independently associated with the enhancement of the PML-PSS or PVS-BG. The odds ratios (95% CIs; P value) were 4.09 × 10-5 (2.39 × 10-8 - 0.07; 0.0078) for the PML-PSS and 1.7 × 10-4 (1.66 × 10-7 - 0.174; 0.014) for the PVS-BG. CONCLUSION: The PML-PSS had the highest signal enhancement at 4 hours after IV-GBCA. When the PML-PSS was seen, there was also often enhancement of the PVS-BG at 4 hours after IV-GBCA. Both observed enhancements were associated with delayed GBCA excretion from the CSF.

DOI： 10.2463/mrms.mp.2022-0110

Pitfalls of Using T2-contrast Enhancement Techniques in 3D-FLAIR to Detect Endolymphatic Hydrops.

Yutaka Kato, Shinji Naganawa, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 22 ( 3 ) page： 335 - 344 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: To determine whether T2-contrast enhancement techniques can be used to diagnose endolymphatic hydrops, we compared fluid signal artifacts with and without T2-contrast enhancement techniques in 3D fluid-attenuated inversion recovery (3D-FLAIR). METHODS: We prepared a custom-made phantom consisting of eight tubes half-filled with saline. Images were obtained using four 3D-FLAIR: without T2-contrast enhancement (Normal), with non-selective T2-inversion recovery (T2-IR), and two with non-selective T2 preparation IR (T2-prep). Scans were performed with and without rice covering the phantom to simulate minimal and severe B0-inhomogeneity conditions. The average signal intensity (SI) values of eight saline tubes were compared between the four sequences and between each other. Comparisons were performed for all measurement slices and the central 10 slices. The images using T2-contrast enhancement technique were obtained from a volunteer and a patient suspected of Meniere's disease. RESULTS: The Normal sequence SI for all slices was significantly lower than that for the other sequences, with smaller standard deviation (SD) and no outliers. Several outliers were detected in the other sequences. The SDs and outliers were larger without rice than with rice. When the central 10 slices with rice, the T2-IR had a significantly higher SI with more outliers compared with the Normal sequence. The T2-prep had no outliers and SIs that were comparable to those of the Normal sequence. However, without rice, the T2-IR and T2-prep sequences had significantly higher SIs with outliers and larger SDs compared to the Normal sequence. In the corresponding images, the Normal sequence achieved excellent fluid suppression, whereas the T2-IR and T2-prep sequences showed high-signal artifacts. Imperfect fluid suppressions were observed in the volunteer image and the endolymphatic hydrops on the post-gadolinium image differed in size and shape in the non-injected T2-IR in the patient image. CONCLUSION: T2-contrast enhancement techniques should be used with caution in 3D-FLAIR for diagnosing endolymphatic hydrops.

DOI： 10.2463/mrms.mp.2022-0017

Effect of Temporal Sampling Rate on Estimates of the Perfusion Parameters for Patients with Moyamoya Disease Assessed with Simultaneous Multislice Dynamic Susceptibility Contrast-enhanced MR Imaging.

Tomohiro Takamura, Shoko Hara, Tadashi Nariai, Yutaka Ikenouchi, Michimasa Suzuki, Toshiaki Taoka, Masahiro Ida, Keiichi Ishigame, Masaaki Hori, Kanako Sato, Koji Kamagata, Kanako Kumamaru, Hidenori Oishi, Sho Okamoto, Yoshio Araki, Kenji Uda, Masakazu Miyajima, Taketoshi Maehara, Motoki Inaji, Yoji Tanaka, Shinji Naganawa, Hisashi Kawai, Toshiki Nakane, Yasuaki Tsurushima, Toshiyuki Onodera, Shuko Nojiri, Shigeki Aoki

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 22 ( 3 ) page： 301 - 312 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: The effect of temporal sampling rate (TSR) on perfusion parameters has not been fully investigated in Moyamoya disease (MMD); therefore, this study evaluated the influence of different TSRs on perfusion parameters quantitatively and qualitatively by applying simultaneous multi-slice (SMS) dynamic susceptibility contrast-enhanced MR imaging (DSC-MRI). METHODS: DSC-MRI datasets were acquired from 28 patients with MMD with a TSR of 0.5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and time to maximum tissue residue function (Tmax) were calculated for eight TSRs ranging from 0.5 to 4.0 s in 0.5-s increments that were subsampled from a TSR of 0.5 s datasets. Perfusion measurements and volume for chronic ischemic (Tmax ≥ 2 s) and non-ischemic (Tmax < 2 s) areas for each TSR were compared to measurements with a TSR of 0.5 s, as was visual perfusion map analysis. RESULTS: CBF, CBV, and Tmax values tended to be underestimated, whereas MTT and TTP values were less influenced, with a longer TSR. Although Tmax values were overestimated in the TSR of 1.0 s in non-ischemic areas, differences in perfusion measurements between the TSRs of 0.5 and 1.0 s were generally minimal. The volumes of the chronic ischemic areas with a TSR ≥ 3.0 s were significantly underestimated. In CBF and CBV maps, no significant deterioration was noted in image quality up to 3.0 and 2.5 s, respectively. The image quality of MTT, TTP, and Tmax maps for the TSR of 1.0 s was similar to that for the TSR of 0.5 s but was significantly deteriorated for the TSRs of ≥ 1.5 s. CONCLUSION: In the assessment of MMD by SMS DSC-MRI, application of TSRs of ≥ 1.5 s may lead to deterioration of the perfusion measurements; however, that was less influenced in TSRs of ≤ 1.0 s.

DOI： 10.2463/mrms.mp.2021-0162

Parasagittal Cystic Lesions May Arise from the Pial Sheath around the Cortical Venous Wall.

Shinji Naganawa, Rintaro Ito, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 22 ( 1 ) page： 143 - 146 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

It has been reported that perivenous cystic structures near the parasagittal dura are associated with the leakage of gadolinium-based contrast agents at 4 hours after intravenous administration. The origin of such cystic structures remains unknown. While reading many cases of MR cisternography, we noticed that some of the cystic structures appeared to connect to the perivenous subpial space. This new imaging finding might facilitate future research of the waste clearance system for the central nervous system.

DOI： 10.2463/mrms.bc.2021-0141

Peripheral Retinal Leakage after Intravenous Administration of a Gadolinium-based Contrast Agent: Age Dependence, Temporal and Inferior Predominance and Potential Implications for Eye Homeostasis.

Shinji Naganawa, Rintaro Ito, Mariko Kawamura, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 22 ( 1 ) page： 45 - 55 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: Peripheral retinal leakage (PRL) of contrast medium from the ora serrata (i.e., the peripheral part of the retina) was recently reported in normal eyes using ultra-widefield fluorescein angiography. We occasionally see PRL of gadolinium-based contrast agents (GBCAs) in the vitreous from the temporal and inferior sides of the ora serrata on MR images of subjects without ophthalmic disease. In this study, we retrospectively evaluated these MR images to determine if PRL was associated with aging. We also evaluated whether the initial leakage appeared in the temporal and inferior sides, and whether there was uniform distribution within the vitreous after 24 hours. METHODS: In 127 subjects (9 volunteers, 85 patients with sudden deafness, and 33 patients with a suspicion of endolymphatic hydrops), pre- and post-contrast-enhanced heavily T2-weighted 3D-fluid attenuated inversion recovery (FLAIR) images were obtained. The presence or absence of PRL was subjectively evaluated. For patients with a suspicion of endolymphatic hydrops, 3D-real inversion recovery (IR) images were also obtained at pre-, 10 mins, 4 hours, and 24 hours after intravenous administration (IV) of GBCA. Four circular ROIs were placed in the vitreous humor and the signal intensity was measured. RESULTS: In the cases with PRL (n = 88) and without PRL (n = 47), the median age was 59 and 47 years, respectively (P = 0.001). At 4 hours after IV-GBCA, the mean signal increase in the inferior temporal ROI was greater than all the other ROIs. At 24 hours after IV-GBCA, no significant difference in signal intensity was observed for the four ROIs. CONCLUSION: PRL of GBCA is age-dependent and occurs mainly from the inferior temporal side of the ora serrata. The contrast effect was uniformly distributed at 24 hours after IV-GBCA. Future observations in a variety of diseases will determine the clinical significance of these findings.

DOI： 10.2463/mrms.mp.2021-0100

Association of MRI Indices of Glymphatic System With Amyloid Deposition and Cognition in Mild Cognitive Impairment and Alzheimer Disease. Reviewed International journal

Koji Kamagata, Christina Andica, Kaito Takabayashi, Yuya Saito, Toshiaki Taoka, Hayato Nozaki, Junko Kikuta, Shohei Fujita, Akifumi Hagiwara, Kouhei Kamiya, Akihiko Wada, Toshiaki Akashi, Katsuhiro Sano, Mitsuo Nishizawa, Masaaki Hori, Shinji Naganawa, Shigeki Aoki

Neurology Vol. 99 ( 24 ) page： E2648 - E2660 2022.12

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND AND OBJECTIVES: The glymphatic system is a whole-brain perivascular network, which promotes CSF/interstitial fluid exchange. Alterations to this system may play a pivotal role in amyloid β (Aβ) accumulation. However, its involvement in Alzheimer's disease (AD) pathogenesis is not fully understood. Here, we investigated the changes in noninvasive MRI measurements related to the perivascular network in patients with mild cognitive impairment (MCI) and AD. Additionally, we explored the associations of MRI measures with neuropsychological score, PET standardized uptake value ratio (SUVR), and Aβ deposition. METHODS: MRI measures, including perivascular space (PVS) volume fraction (PVSVF), fractional volume of free water in white matter (FW-WM), and index of diffusivity along the perivascular space (ALPS index) of patients with MCI, those with AD, and healthy controls from the Alzheimer's Disease Neuroimaging Initiative database were compared. MRI measures were also correlated with the levels of CSF biomarkers, PET SUVR, and cognitive score in the combined subcohort of patients with MCI and AD. Statistical analyses were performed with age, sex, years of education, and APOE status as confounding factors. RESULTS: In total, 36 patients with AD, 44 patients with MCI, and 31 healthy controls were analyzed. Patients with AD had significantly higher total, WM, and basal ganglia PVSVF (Cohen's d = 1.15-1.48; p < 0.001), and FW-WM (Cohen's d = 0.73; p < 0.05) and a lower ALPS index (Cohen's d = 0.63; p < 0.05) than healthy controls. Meanwhile, the MCI group only showed significantly higher total (Cohen's d = 0.99; p < 0.05) and WM (Cohen's d = 0.91; p < 0.05) PVSVF. Low ALPS index was associated with lower CSF Aβ42 (r s = 0.41, p fdr = 0.026), FDG-PET uptake (r s = 0.54, p fdr < 0.001), and worse multiple cognitive domain deficits. High FW-WM was also associated with lower CSF Aβ42 (r s = -0.47, p fdr = 0.021) and worse cognitive performances. CONCLUSION: Our study indicates that changes in PVS-related MRI parameters occur in MCI and AD, possibly due to impairment of the glymphatic system. We also report the associations between MRI parameters and Aβ deposition, neuronal change, and cognitive impairment in AD.

DOI： 10.1212/WNL.0000000000201300

Impact of tissue properties on time-dependent alterations in apparent diffusion coefficient: A phantom study using oscillating gradient spin-echo and pulsed gradient spin-echo sequences Reviewed

Interstitial Fluidopathy of the Central Nervous System: An Umbrella Term for Disorders with Impaired Neurofluid Dynamics. Invited Reviewed

Toshiaki Taoka, Rintaro Ito, Rei Nakamichi, Toshiki Nakane, Hisashi Kawai, Shinji Naganawa

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 23 ( 1 ) page： 1 - 13 2022.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

Interest in interstitial fluid dynamics has increased since the proposal of the glymphatic system hypothesis. Abnormal dynamics of the interstitial fluid have been pointed out to be an important factor in various pathological statuses. In this article, we propose the concept of central nervous system interstitial fluidopathy as a disease or condition in which abnormal interstitial fluid dynamics is one of the important factors for the development of a pathological condition. We discuss the aspects of interstitial fluidopathy in various diseases, including Alzheimer's disease, Parkinson's disease, normal pressure hydrocephalus, and cerebral small vessel disease. We also discuss a method called "diffusion tensor image analysis along the perivascular space" using MR diffusion images, which is used to evaluate the degree of interstitial fluidopathy or the activity of the glymphatic system.

DOI： 10.2463/mrms.rev.2022-0012

Kazushige Ichikawa, Toshiaki Taoka, Masanori Ozaki, Mayuko Sakai, Hiroshi Yamaguchi, Shinji Naganawa

Japanese Journal of Radiology Vol. 40 ( 9 ) page： 970 - 978 2022.9

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: The purpose of this study was to investigate whether the changes in apparent diffusion coefficients (ADCs) due to differences in diffusion time reflect tissue properties in actual measurements of phantoms. MATERIALS AND METHODS: Various n-alkane phantoms and sucrose/collagen phantoms with various collagen densities were set up with and without polyvinyl alcohol (PVA) foam with an average pore diameter of 300 μm. Thus, n-alkanes or sucrose/collagen represented substrate viscosity and the presence of PVA foam represented tissue structure with septum. Diffusion-weighted images with various diffusion times (7.71-60 ms) were acquired using pulsed-gradient spin-echo (PGSE) and oscillating-gradient spin-echo (OGSE) sequences. The ADCs of the phantoms with and without PVA foam were calculated. RESULTS: The ADCs of some of the phantoms without PVA decreased with diffusion times decreased. In the n-alkane phantoms, only C8H18 showed significantly different ADCs depending on the use of PVA foam in the OGSE sequence. On the other hand, sucrose/collagen phantoms showed significant differences according to diffusion time. The ADCs of the phantoms decreased as the molecular size of the n-alkanes or collagen density of the sucrose/collagen phantom increased. Compared to phantoms without PVA foam, the ADC of the phantoms with PVA foam decreased as the diffusion time increased. CONCLUSION: Changes in ADCs due to differences in diffusion time reflect tissue properties in actual measurements of phantoms. These changes in ADCs can be used for tissue characterization in vivo.

DOI： 10.1007/s11604-022-01281-2

Spontaneous regression of asymptomatic tumefactive perivascular spaces in the anterior temporal lobe.

Miki Hashida, Yoshitaka Nagashima, Yusuke Nishimura, Kaoru Eguchi, Toshiaki Taoka, Hisashi Kawai, Ryuta Saito

Nagoya journal of medical science Vol. 84 ( 3 ) page： 678 - 685 2022.8

Language：English Publishing type：Research paper (scientific journal)

Perivascular spaces are fluid-filled spaces that surround the perforating vessels of the brain and are normal findings on brain imaging. These are usually asymptomatic and are considered a manifestation of aging. Perivascular spaces occasionally undergo significant enlargement and are referred to as tumefactive perivascular spaces, which are often indistinguishable from neoplastic lesions. Spontaneous regression of tumefactive perivascular spaces during follow-up is rare. We report the imaging findings and clinical course of a patient who showed spontaneous regression of tumefactive perivascular spaces in the anterior temporal lobe, together with a literature review and discussion regarding the characteristics and pathogenesis of spontaneous regression of tumefactive perivascular spaces. Most studies in the available literature report tumefactive perivascular spaces in the anterior temporal lobe; in our view, the characteristics of anterior temporal lobe tumefactive perivascular spaces may differ from those of tumefactive perivascular spaces that occur at other locations.

DOI： 10.18999/nagjms.84.3.678

Contrast-Enhanced Fluid-Attenuated Inversion Recovery in Neuroimaging: A Narrative Review on Clinical Applications and Technical Advances. Reviewed International coauthorship International journal

Sung Jun Ahn, Toshiaki Taoka, Won-Jin Moon, Shinji Naganawa

Journal of magnetic resonance imaging : JMRI Vol. 56 ( 2 ) page： 341 - 353 2022.8

Language：English Publishing type：Research paper (scientific journal)

While contrast-enhanced fluid-attenuated inversion recovery (FLAIR) has long been regarded as an adjunct sequence to evaluate leptomeningeal disease in addition to contrast-enhanced T1-weighted imaging, it is gradually being used for more diverse pathologies beyond leptomeningeal disease. Contrast-enhanced FLAIR is known to be highly sensitive to low concentrations of gadolinium within the fluid. Accordingly, recent research has suggested the potential utility of contrast-enhanced FLAIR in various kinds of disease, such as Meniere's disease, seizure, stroke, traumatic brain injury, and brain metastasis, in addition to being used for visualizing glymphatic dysfunction. However, its potential applications have been reported sporadically in an unorganized manner. Furthermore, the exact mechanism for its superior sensitivity to low concentrations of gadolinium has not been fully understood. Rapidly developing magnetic resonance technology and unoptimized parameters for FLAIR may challenge its accurate application in clinical practice. This review provides the fundamental mechanism of contrast-enhanced FLAIR, systematically describes its current and potential clinical application, and elaborates on technical considerations for its optimization. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 5.

DOI： 10.1002/jmri.28117

Letter to editor on the article "A non-invasive, automated diagnosis of Menière's disease using radiomics and machine learning on conventional magnetic resonance imaging: a multicentric, case-controlled feasibility study" by van der Lubbe Mfja et al. International journal

Shinji Naganawa, Rintaro Ito, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

La Radiologia medica Vol. 127 ( 4 ) page： 458 - 459 2022.4

Hybrid 3D T1-weighted gradient-echo sequence for fiducial marker detection and tumor delineation via magnetic resonance imaging in liver stereotactic body radiation therapy. International journal

Yutaka Kato, Takeshi Kamomae, Motoki Kumagai, Yumi Oie, Yumiko Noguchi, Kuniyasu Okudaira, Mariko Kawamura, Toshiaki Taoka, Shinji Naganawa

Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) Vol. 95 page： 9 - 15 2022.3

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: Gold fiducial markers are used to guide liver stereotactic body radiation therapy (SBRT) and are hard to detect by magnetic resonance imaging (MRI). In this study, the parameters of the three-dimensional T1-weighted turbo gradient-echo (3D T1W-GRE) sequence were optimized for gold marker detection without degrading tumor delineation. METHODS: Custom-made phantoms mimicking tumor and normal liver parenchyma were prepared and embedded with a gold marker. The 3D T1W-GRE was scanned by varying echo time (TE), bandwidth (BW), flip angle (FA), and base matrix size. The signal-to-noise ratio (SNR), contrast ratio (CR), and relative standard deviation (RSD) of the signal intensity in the area including the gold marker were evaluated, and the parameters were optimized accordingly. The modified 3D T1W-GRE (called HYBRID) was compared with the conventional T1W-GRE- and T2*-sequences in both phantom and clinical studies. In the clinical study of six patients with primary liver tumors, two observers visually assessed marker detection, tumor delineation, and overall image quality on a four-point scale. RESULTS: In the phantom study, HYBRID showed significantly higher SNR and RSD than those of conventional T1W-GRE (P < 0.001). In the clinical study, HYBRID yielded significantly higher scores than conventional T1W-GRE did in terms of marker detection (P < 0.001). The scores of both sequences were not statistically different in terms of tumor delineation and overall image quality (P = 0.56 and P = 0.32). CONCLUSIONS: The proposed HYBRID sequence improved gold fiducial marker detection without degrading tumor delineation in MRI for SBRT of primary liver tumor.

DOI： 10.1016/j.ejmp.2022.01.003

Water Diffusivity Changes Along the Perivascular Space After Lumboperitoneal Shunt Surgery in Idiopathic Normal Pressure Hydrocephalus. International journal

Junko Kikuta, Koji Kamagata, Toshiaki Taoka, Kaito Takabayashi, Wataru Uchida, Yuya Saito, Christina Andica, Akihiko Wada, Kaito Kawamura, Chihiro Akiba, Madoka Nakajima, Masakazu Miyajima, Shinji Naganawa, Shigeki Aoki

Frontiers in neurology Vol. 13 page： 843883 - 843883 2022.2

Language：English Publishing type：Research paper (scientific journal)

Background: The aim of this study was to evaluate the water diffusivity changes along the perivascular space after lumboperitoneal shunt (LPS) surgery in idiopathic normal pressure hydrocephalus. Methods: Nine patients diagnosed with idiopathic normal pressure hydrocephalus (iNPH; three men and six women, mean age ± SD = 75.22 ± 5.12 years) according to the guidelines for iNPH in Japan were included in the study. Post-LPS surgery, six patients with iNPH who exhibited improvement in symptoms were defined as responder subjects, while three patients with iNPH who did not were defined as non-responder subjects. We calculated the mean analysis along the perivascular space (ALPS) index of the left and right hemispheres and compared the differences between pre- and post-LPS surgery mean ALPS indices in iNPH patients. In the responder or non-responder subjects, the mean ALPS indices in the pre- and post-operative iNPH groups were compared using Wilcoxon signed-rank tests. Next, correlation analyses between pre- and post-operation changes in the mean ALPS index and clinical characteristics were conducted. Results: The mean ALPS index of the post-operative iNPH group was significantly higher than that of the pre-operative iNPH group (p = 0.021). In responder subjects, the mean ALPS index of the post-operative iNPH group was significantly higher than that of the pre-operative iNPH group (p = 0.046). On the other hand, in the non-responder subjects, the mean ALPS index of the post-operative iNPH group was not significantly different compared to the pre-operative iNPH group (p = 0.285). The mean ALPS index change was not significantly correlated with changes in the Mini-Mental State Examination (MMSE) score (r = -0.218, p = 0.574), Frontal Assessment Battery (FAB) score (r = 0.185, p = 0.634), Trail Making Test A (TMTA) score (r = 0.250, p = 0.516), and Evans' index (r = 0.109, p = 0.780). In responder subjects, the mean ALPS index change was significantly correlated with Evans' index in pre-operative patients with iNPH (r = 0.841, p = 0.036). Conclusion: This study demonstrates the improved water diffusivity along perivascular space in patients with iNPH after LPS surgery. This could be indicative of glymphatic function recovery following LPS surgery.

DOI： 10.3389/fneur.2022.843883

＜Editors' Choice＞ Evaluation of system-related magnetic resonance imaging geometric distortion in radiation therapy treatment planning: two approaches and effectiveness of three-dimensional distortion correction.

Yutaka Kato, Kuniyasu Okudaira, Takeshi Kamomae, Motoki Kumagai, Youta Nagai, Toshiaki Taoka, Yoshiyuki Itoh, Shinji Naganawa

Nagoya journal of medical science Vol. 84 ( 1 ) page： 29 - 41 2022.2

Language：English Publishing type：Research paper (scientific journal)

We propose two methods to evaluate system-related distortion in magnetic resonance imaging (MRI) in radiation therapy treatment planning (RTP) and demonstrate the importance of three-dimensional (3D) distortion correction (DC) by quantitatively measuring the distortion magnitude. First, a small pin phantom was scanned at multiple positions using an external laser guide for accurate phantom placement and combined into one image encompassing a large area. Direct plane images were used for evaluating in-plane distortion and multiplanar reconstruction images for through-plane distortion with no DC, two-dimensional (2D) DC, and 3D DC. Second, a large grid sheet was scanned as the direct plane of the phantom placement. The distortion magnitude was determined by measuring the displacement between the MRI and reference coordinates. The measured distortions were compared between in- and through-plane when applying DC and between the two methods. The small pin phantom method can be used to evaluate a wide range of distortions, whereas data from the entire plane can be obtained with a single scan using the grid sheet without a laser guide. The mean distortion magnitudes differed between the methods. Furthermore, the 3D DC reduced in- and through-plane distortions. In conclusion, the small pin phantom method can be used to evaluate a wide range of distortions by creating a combined image, whereas the grid sheet method is simpler, accurate, repeatable, and does not require a special-order phantom or laser guide. As 3D DC reduces both in- and through-plane distortions, it can be used to improve RTP quality.

DOI： 10.18999/nagjms.84.1.29

特集 "-pathy"でせまる中枢神経疾患 CNS interstitial fluidopathy ─ 膜と水動態の異常

特集 "-pathy"でせまる中枢神経疾患序説にかえて-umbrella term の意義とpenumbra

田岡俊昭

画像診断 Vol. 42 ( 2 ) page： 134 - 135 2022.1

田岡俊昭

画像診断 Vol. 42 ( 2 ) page： 197 - 207 2022.1

Features from MRI texture analysis associated with survival outcomes in triple-negative breast cancer patients.

Saki Kamiya, Hiroko Satake, Yoko Hayashi, Satoko Ishigaki, Rintaro Ito, Mariko Kawamura, Toshiaki Taoka, Shingo Iwano, Shinji Naganawa

Breast cancer (Tokyo, Japan) Vol. 29 ( 1 ) page： 164 - 173 2022.1

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: The purpose of the study is to evaluate the associations between intratumoral or peritumoral textural features derived from pretreatment magnetic resonance imaging (MRI) and recurrence-free survival (RFS) in triple-negative breast cancer (TNBC) patients. METHODS: Forty-three patients with TNBC who underwent preoperative MRI between February 2008 and March 2014 were included. We performed two-dimensional texture analysis on the intratumoral or peritumoral region of interest (ROI) on axial of T2-weighted image (T2WI), dynamic contrast-enhanced (DCE)-MRI and DCE-MRI subtraction images. We also analyzed histopathological data. Cox proportional hazards models were used to investigate associations with survival outcomes. RESULTS: Twelve of the 43 patients (27.9%) had recurrence disease, at a median of 32.5 months follow-up (1.4-61.5 months). In univariate analysis, nine texture features in T2WI and DCE-MRI subtraction images were significantly associated with RFS. In multivariate analysis, intratumoral difference entropy in DCE-MRI subtraction images in the initial phase (hazard ratio 11.71; 95% confidence interval (CI) [1.41, 97.00]; p value 0.023) and, peritumoral difference variance in DCE-MRI subtraction images in the delayed phase (hazard ratio 9.60; 95% CI [1.98, 46.51]; p value 0.005), were both independently associated with RFS. Moreover, multivariate analysis revealed the presence of lymphovascular invasion as independently associated with RFS (hazard ratio 8.13; 95% CI [2.16, 30.30]; p value 0.002). CONCLUSIONS: At pretreatment MRI, an intratumoral and peritumoral quantitative approach using texture analysis has the potential to serve as a prognostic marker in patients with TNBC.

DOI： 10.1007/s12282-021-01294-1

An Investigation of Water Diffusivity Changes along the Perivascular Space in Elderly Subjects with Hypertension

J. Kikuta, K. Kamagata, K. Takabayashi, T. Taoka, H. Yokota, C. Andica, A. Wada, Y. Someya, Y. Tamura, R. Kawamori, H. Watada, S. Naganawa, S. Aoki

American Journal of Neuroradiology Vol. 43 ( 1 ) page： 48 - 55 2022.1

The Glymphatic System: A Review of the Challenges in Visualizing its Structure and Function with MR Imaging.

Shinji Naganawa, Toshiaki Taoka

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 21 ( 1 ) page： 182 - 194 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

The central nervous system (CNS) was previously thought to be the only organ system lacking lymphatic vessels to remove waste products from the interstitial space. Recently, based on the results from animal experiments, the glymphatic system was hypothesized. In this hypothesis, cerebrospinal fluid (CSF) enters the periarterial spaces, enters the interstitial space of the brain parenchyma via aquaporin-4 (AQP4) channels in the astrocyte end feet, and then exits through the perivenous space, thereby clearing waste products. From the perivenous space, the interstitial fluid drains into the subarachnoid space and meningeal lymphatics of the parasagittal dura. It has been reported that the glymphatic system is particularly active during sleep. Impairment of glymphatic system function might be a cause of various neurodegenerative diseases such as Alzheimer's disease, normal pressure hydrocephalus, glaucoma, and others. Meningeal lymphatics regulate immunity in the CNS. Many researchers have attempted to visualize the function and structure of the glymphatic system and meningeal lymphatics in vivo using MR imaging. In this review, we aim to summarize these in vivo MR imaging studies and discuss the significance, current limitations, and future directions. We also discuss the significance of the perivenous cyst formation along the superior sagittal sinus, which is recently discovered in the downstream of the glymphatic system.

DOI： 10.2463/mrms.rev.2020-0122

MR Imaging of Endolymphatic Hydrops in Five Minutes.

Shinji Naganawa, Rintaro Ito, Hisashi Kawai, Mariko Kawamura, Toshiaki Taoka, Mayuko Sakai, Kazushige Ichikawa, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 21 ( 3 ) page： 401 - 405 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

In this study, we present images acquired by a fast-imaging method for the evaluation of endolymphatic hydrops after intravenous administration of a single dose of gadolinium-based contrast agent. We utilized the hybrid of reversed image of MR cisternography and a positive perilymph signal by heavily T2- weighted 3D-fluid attenuated inversion recovery-multiplied by T2 (HYDROPS2-Mi2) method combined with deep learning reconstruction denoising. The scan time for the fast protocol was approximately 5 mins, which is far shorter than previously reported scan times. The fast acquisition provides similar image quality and less motion artifacts compared to the longer method.

DOI： 10.2463/mrms.ici.2021-0022

Cross-sectional Area of the Superior Petrosal Sinus is Reduced in Patients with Significant Endolymphatic Hydrops.

Shinji Naganawa, Rintaro Ito, Hisashi Kawai, Mariko Kawamura, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 21 ( 3 ) page： 459 - 467 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: To evaluate the relationship between the size of the venous structures related to the inner ear and the degree of endolymphatic hydrops (EH). METHODS: Thirty-four patients with a suspicion of EH underwent whole brain MR imaging including the inner ear. Images were obtained pre- and post-administration, and at 4 and 24 hours after the intravenous administration of a gadolinium-based contrast agent (IV-GBCA). The cross-sectional areas (CSA) of the internal jugular vein (IJV), superior petrosal sinus (SPS), and inferior petrosal sinus (IPS) were measured on the magnetization prepared rapid acquisition of gradient echo (MPRAGE) images obtained immediately after the IV-GBCA. The grade of EH was determined on the hybrid of reversed image of positive endolymph signal and native image of positive perilymph signal (HYDROPS) images obtained at 4 hours after IV-GBCA as no, mild, and significant EH according to the previously proposed grading system for the cochlea and vestibule, respectively. The ipsilateral CSA was compared between groups with each level of EH grade. P < 0.05 was considered statistically significant. RESULTS: There were no statistically significant differences between EH grades for the CSA of the IJV or that of the IPS in either the cochlea or the vestibule. The CSA of the SPS in the groups with significant EH was significantly smaller than that in the group with no EH, for both the cochlea (P < 0.01) and the vestibule (P < 0.05). In an ROC analysis to predict significant EH, the cut-off CSA value in the SPS was 3.905 mm2 for the cochlea (AUC: 0.8762, 95% confidence interval [CI]: 0.7952‒0.9572) and 3.805 mm2 for the vestibule (AUC: 0.7727, 95% CI: 0.6539‒0.8916). CONCLUSION: In the ears with significant EH in the cochlea or vestibule, the CSA of the ipsilateral SPS was smaller than in the ears without EH.

DOI： 10.2463/mrms.mp.2021-0010

特集撮った,読んだ,わかった! 認知症画像診断認知症画像のカッティングエッジ2:Glymphaticシステム,CNS interstitial fluidopathyの概念

田岡俊昭

画像診断 Vol. 41 ( 14 ) page： 1543 - 1553 2021.11

FLUID study: study protocol for an open-label, single-centre pilot study to investigate the efFect of Lemborexant on sleep management in Japanese sUbjects aged 50 years and older with Insomnia Disorder. International journal

Ippei Okada, Kunihiro Iwamoto, Seiko Miyata, Akihiro Fujimoto, Masaki Tanaka, Manabu Amano, Nao Matsuyama, Toshiaki Taoka, Shinji Naganawa, Norio Ozaki

BMJ open Vol. 11 ( 11 ) page： e054885 2021.11

Language：English Publishing type：Research paper (scientific journal)

INTRODUCTION: Bidirectional associations have been reported between sleep disturbance and both cognitive impairment, including Alzheimer's disease and amyloid beta-peptide (Aβ) accumulation. These relationships can be explained by the glymphatic system, which acts as a garbage drainage system in the brain. As interstitial fluid dynamics are suggested to increase during sleep, clearance of Aβ can be influenced by sleep disturbance or deprivation. We hypothesised that using lemborexant, an orexin receptor antagonist, to improve sleep quality would also improve the function of the glymphatic system. We plan to examine the effect of lemborexant on sleep quality and the glymphatic system among patients with insomnia disorder. METHODS AND ANALYSIS: This pilot study is designed as an open-label, single-arm, single-centre trial. Thirty patients aged 50 years and over with insomnia will be recruited. The participants will take lemborexant (5 mg) at bedtime for 12 weeks and undergo a home-based sleep study at baseline and weeks 4 and 12, as well as MRI examinations to evaluate the glymphatic system at baseline and week 12. The primary outcome will be changes in objective sleep parameters as evaluated using a sleep monitoring system. The secondary outcomes will be changes in subjective sleep parameters. The relationships between changes in sleep parameters and the glymphatic system will be evaluated using diffusion tensor image analysis along the perivascular space, which is called the ALPS-index. Sleep parameters and the ALPS-index will be analysed using a paired t-test or Pearson's correlation coefficient. ETHICS AND DISSEMINATION: The study protocol was approved by Nagoya University Certified Review Board. The findings from this research will be published in peer-reviewed journals and be presented at local, national and international conferences. TRIAL REGISTRATION NUMBER: jRCTs041210024.

DOI： 10.1136/bmjopen-2021-054885

Magnetic resonance cisternography imaging findings related to the leakage of Gadolinium into the subarachnoid space

Rei Nakamichi, Toshiaki Taoka, Hisashi Kawai, Tadao Yoshida, Michihiko Sone, Shinji Naganawa

Japanese Journal of Radiology Vol. 39 ( 10 ) page： 927 - 937 2021.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

<title>Abstract</title><sec>
<title>Purpose</title>
To identify magnetic resonance cisternography (MRC) imaging findings related to Gadolinium-based contrast agent (GBCA) leakage into the subarachnoid space.

</sec><sec>
<title>Materials and methods</title>
The number of voxels of GBCA leakage (V-leak) on 3D-real inversion recovery images was measured in 56 patients scanned 4 h post-intravenous GBCA injection. Bridging veins (BVs) were identified on MRC. The numbers of BVs with surrounding cystic structures (BV-cyst), with arachnoid granulations protruding into the superior sagittal sinus (BV-AG-SSS) and the skull (BV-AG-skull), and including any of these factors (BV-incl) were recorded. Correlations between these variables and V-leak were examined based on the Spearman’s rank correlation coefficient. Receiver-operating characteristic (ROC) curves were generated to investigate the predictive performance of GBCA leakage.

</sec><sec>
<title>Results</title>
V-leak and the number of BV-incl were strongly correlated (<italic>r</italic> = 0.609, <italic>p</italic> < 0.0001). The numbers of BV-cyst and BV-AG-skull had weaker correlations with V-leak (<italic>r</italic> = 0.364, <italic>p</italic> = 0.006; <italic>r</italic> = 0.311, <italic>p</italic> = 0.020, respectively). The number of BV-AG-SSS was not correlated with V-leak. The ROC curve for contrast leakage exceeding 1000 voxels and the number of BV-incl had moderate accuracy, with an area under the curve of 0.871.

</sec><sec>
<title>Conclusion</title>
The number of BV-incl may be a predictor of GBCA leakage and a biomarker for waste drainage function without using GBCA.

</sec>

DOI： 10.1007/s11604-021-01137-1

Changes in Vessel Wall Enhancement Related to the Recent Neurological Symptoms in Patients with Moyamoya Disease. Reviewed

Other Link： https://link.springer.com/article/10.1007/s11604-021-01137-1/fulltext.html

Shinsuke Muraoka, Toshiaki Taoka, Hisashi Kawai, Sho Okamoto, Kenji Uda, Shinji Naganawa, Yoshio Araki

Neurologia medico-chirurgica Vol. 61 ( 9 ) page： 515 - 520 2021.9

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Neurosurgical Society

Moyamoya disease (MMD) causes intracranial arterial stenosis progression. The progression of intracranial arterial stenosis will increase the risk of ischemic cerebrovascular events. This study aims to investigate the relationship between intracranial arterial stenosis progression, vessel wall enhancement (VWE), and the recent neurological symptoms. A total of 39 MMD patients (12 male; 37.6 ± 18.0 years old) were registered in this study analysis between April 2016 and July 2018. All patients received MRI at registration and 6, 12, and 24 months post-registration. The incidence of ischemic cerebrovascular events (transit ischemic attacks or cerebral infarction) was checked until December 2018. We evaluated the relationship between the intensity of VWE, intracranial arterial stenosis, and the recent neurological symptoms. During the mean follow-up period of 13.8 ± 5.5 months, the changes in VWE were observed in 33 hemispheres (42.3%), stenosis progression was observed in 21 hemispheres (26.9%), and recent neurological symptoms occurred in 10 hemispheres (12.8%). Stenosis progression was observed in 11 hemispheres (33.3%) in the VWE(+) group and ten hemispheres (22.2%) in the VWE(-) group (p = 0.310). The recent neurological symptoms were observed in eight hemispheres (21.2%) in the VWE(+) group and two hemispheres (4.44%) in the VWE(-) group (odds ratio 6.88, 95% confidence interval 1.35-34.98, p = 0.015). The intensity of VWE sometimes changes. The changes in VWE were significantly associated with the recent neurological symptoms but not with stenosis progression.

DOI： 10.2176/nmc.oa.2021-0058

Neurofluid as Assessed by Diffusion-Weighted Imaging. International journal

Toshiaki Taoka

Magnetic resonance imaging clinics of North America Vol. 29 ( 2 ) page： 243 - 251 2021.5

Language：English Publishing type：Research paper (scientific journal)

The glymphatic system hypothesis is associated with the circulation of cerebrospinal fluid (CSF) in the skull and interstitial fluid (ISF) in the brain. There are several imaging techniques to visualize the dynamics of CSF and ISF. Magnetic resonance imaging (MRI) is one of the promising modalities for glymphatic imaging and diffusion MRI is expected imaging tool. Several disorders are associated with glymphatic dysfunction or impairment in the dynamics of CSF or ISF. The Central Nervous System interstitial fluidopathy concept has been proposed to encompass diseases with pathologies that are predominantly associated with abnormal ISF/CSF dynamics.

DOI： 10.1016/j.mric.2021.01.002

Associations among Cognitive Functions, Plasma DNA, and Diffusion Tensor Image along the Perivascular Space (DTI-ALPS) in Patients with Parkinson's Disease. International coauthorship International journal

Hsiu-Ling Chen, Pei-Chin Chen, Cheng-Hsien Lu, Nai-Wen Tsai, Chiun-Chieh Yu, Kun-Hsien Chou, Yun-Ru Lai, Toshiaki Taoka, Wei-Che Lin

Oxidative medicine and cellular longevity Vol. 2021 page： 4034509 - 4034509 2021.2

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Parkinson's disease (PD) is a common neurodegenerative disease associated with accumulation of misfolding proteins and increased neuroinflammation, which may further impair the glymphatic system. The purpose of this study was to utilize diffusion tensor image analysis along the perivascular space (DTI-ALPS) to evaluate glymphatic system activity and its relationship with systemic oxidative stress status in PD patients. METHODS: Magnetic resonance imaging and neuropsychological tests were conducted on 25 PD patients with normal cognition (PDN), 25 PD patients with mild cognitive impairment (PD-MCI), 38 PD patients with dementia (PDD), and 47 normal controls (NC). Oxidative stress status was assessed by plasma DNA level. Differences in ALPS-index among the subgroups were assessed and further correlated with cognitive functions and plasma DNA levels. RESULTS: The PD-MCI and PDD groups showed significantly lower ALPS-index compared to normal controls. The ALPS-index was inversely correlated with plasma nuclear DNA, mitochondrial DNA levels, and cognitive scores. CONCLUSIONS: Lower diffusivity along the perivascular space, represented by lower ALPS-index, indicates impairment of the glymphatic system in PD patients. The correlation between elevated plasma nuclear DNA levels and lower ALPS-index supports the notion that PD patients may exhibit increased oxidative stress associated with glymphatic system microstructural alterations.

DOI： 10.1155/2021/4034509

ISMRM2020における富樫かおり先生のGold Medal受賞と長縄慎二先生のSenior Fellow選出を記念して

黒田輝, 小畠隆行, 三木幸雄, 田岡俊昭

日本磁気共鳴医学会雑誌 Vol. 41 ( 1 ) page： 1 - 4 2021.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：日本磁気共鳴医学会

2020年8月にウェブ開催されたISMRM（国際磁気共鳴医学会）において，京都大学の富樫かおり先生がGold Medalを受賞され，名古屋大学の長縄慎二先生がSenior Fellowに選出されました．同じ年の大会で日本人が同時に2名選出されることは初めてのことであり，MRI研究における日本の大きなプレゼンスを示す出来事でもありました．　この度，この快挙を記念して，お二人とご縁の深い先生方からの特別寄稿をいただきましたので，ここに掲載させて頂きます．

DOI： 10.2463/jjmrm.2020-1724

Evaluating the Effect of Arterial Pulsation on Cerebrospinal Fluid Motion in the Sylvian Fissure of Patients with Middle Cerebral Artery Occlusion Using Low b-value Diffusion-weighted Imaging

Toshiaki Taoka, Hisashi Kawai, Toshiki Nakane, Takashi Abe, Rei Nakamichi, Rintaro Ito, Yutaro Sasaki, Ayumi Nishida, Shinji Naganawa

Magnetic Resonance in Medical Sciences Vol. 20 ( 4 ) page： 371 - 377 2021

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: Decrease in signal of the cerebrospinal fluid (CSF) on low b-value diffusion weighted image (DWI) due to non-uniform flow can provide additional information regarding CSF motion. The purpose of the current study was to evaluate whether arterial pulsations constitute the driving force of CSF motion. METHODS: We evaluated the CSF signals within the Sylvian fissure on low b-value DWI in 19 patients with unilateral middle cerebral artery (MCA) occlusion. DWI with b-value of 500 s/mm2 was evaluated for a decrease in CSF signal within the Sylvian fissure including the Sylvian vallecula and lower, middle, and higher Sylvian fissures and graded as follows: the same as contralateral side; smaller signal decrease than that on contralateral side; and no signal decrease. MR angiography (MRA) findings of MCA were graded as follows: the same as contralateral, lower signal than contralateral signal, and no signal. In 15 patients, regional cerebral blood flow (rCBF) was evaluated using single-photon emission computed tomography (SPECT) studies and graded as >90%, 90%-70%, and <70% rCBF compared to contralateral. The correlations between the gradings were evaluated using G likelihood-ratio test. RESULTS: There was no statistically significant correlation between the MRA and low b-value DWI gradings of CSF in all areas. There were statistically significant correlations between the decreases in CBF on SPECT and CSF signals in the middle Sylvian fissure. CONCLUSION: The driving force of CSF pulsation in the Sylvian sinus may be related to the pulsations of the cerebral hemisphere rather than direct arterial pulsations.

DOI： 10.2463/mrms.mp.2020-0121

Relationship between Time-dependent Signal Changes in Parasagittal Perivenous Cysts and Leakage of Gadolinium-based Contrast Agents into the Subarachnoid Space.

Shinji Naganawa, Rintaro Ito, Rei Nakamichi, Mariko Kawamura, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 4 ) page： 378 - 384 2021

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: To investigate the association between signal changes over time in perivenous cystic structures near the superior sagittal sinus and leakage of a gadolinium-based contrast agent (GBCA) into the subarachnoid space in patients with suspected endolymphatic hydrops. METHODS: Fifty-one cystic structures in 27 cases were evaluated. The signal intensity of the cystic structures was measured on 3D real inversion recovery (3D-real IR) images obtained at pre-, and at 10 min, 4 hrs and 24 hrs post-intravenous administration (IV) of GBCA. Signal enhancement of the cystic structures from the pre-contrast images at each time point was compared in subjects with leakage (positive) versus those without leakage (negative) using an ANOVA. Fisher's exact probability test was used to compare the maximum contrast-enhanced time point between positive and negative groups. We used 5% as a threshold to determine statistical significance. RESULTS: In leakage positive subjects, mean signal enhancement of the cysts was significantly greater at 4 and 24 hrs compared to 10 min. However, although there was a trend of an increase from 4 to 24 hrs, the difference was not significant. In the leakage negative group, mean signal enhancement of the cysts was significantly higher at 4 hrs compared to 10 min and 24 hrs. There was no significant difference between 10 min and 24 hrs. In the positive group, the maximum signal increase was found in 10/38 and 28/38 cysts at 4 and 24 hrs after IV-GBCA, respectively. In the leakage negative group, the maximum signal increase was found in 10/13 and 3/13 cysts at 4 and 24 hrs, respectively (P = 0.0019). CONCLUSION: There was an association between signal changes over time after IV-GBCA in perivenous cystic structures and leakage of GBCA. Further research to clarify the impact of cystic structures on the function of the waste clearance system of the brain is warranted.

DOI： 10.2463/mrms.mp.2020-0138

Relationship between Parasagittal Perivenous Cysts and Leakage of Gadolinium-based Contrast Agents into the Subarachnoid Space around the Cortical Veins after Intravenous Administration. Reviewed

Shinji Naganawa, Rintaro Ito, Rei Nakamichi, Mariko Kawamura, Hisashi Kawai, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 3 ) page： 245 - 252 2021

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: The purpose of this retrospective study was to investigate the relationship between the number and size of cystic structures around the cortical veins near the superior sagittal sinus and the leakage of gadolinium-based contrast agent (GBCA) around the cortical veins. METHODS: Of 190 patients (91 male and 99 female), that were scanned at 4 h after an intravenous injection of GBCA as a diagnostic examination for endolymphatic hydrops, 6 patients with GBCA leakage were younger than the previously proposed threshold age of 37.3 years for leakage. Six age-matched patients without leakage were also included for reference. In addition, we included 8 cases without leakage that were older than the hypothesized threshold of 37.3 years, as well as 8 age-matched patients with GBCA leakage into the cerebrospinal fluid space. The number of cysts was counted and the sizes were measured in these 28 patients (age: 32-60 years old, 13 men and 15 women). RESULTS: The mean number of cysts surrounding the cortical veins in the parasagittal region was 4.29 ± 1.77 vs. 1.79 ± 1.05 (P = 0.0001) in the subjects with and without GBCA leakage, respectively. The mean size of the largest cysts was at 8.89 ± 3.49 mm vs. 5.69 ± 2.29 (P = 0.009) in the subjects with and without GBCA leakage, respectively. CONCLUSION: The number and size of the perivenous cystic structures near the superior sagittal sinus is greater in subjects with GBCA leakage into the subarachnoid space compared with those without leakage. Future research regarding the histological and functional details of these parasagittal cystic structures is needed.

DOI： 10.2463/mrms.mp.2020-0062

Intracranial Distribution of Intravenously Administered Gadolinium-based Contrast Agent over a Period of 24 Hours: Evaluation with 3D-real IR Imaging and MR Fingerprinting. Reviewed

Shinji Naganawa, Rintaro Ito, Yutaka Kato, Hisashi Kawai, Toshiaki Taoka, Tadao Yoshida, Katsuya Maruyama, Katsutoshi Murata, Gregor Körzdörfer, Josef Pfeuffer, Mathias Nittka, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 1 ) page： 91 - 98 2021

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: To evaluate the feasibility for the detection of slight contrast effects after intravenous administration of single dose gadolinium-based contrast agent (IV-SD-GBCA), the time course of the GBCA distribution up to 24 h was examined in various fluid spaces and brain parenchyma using 3D-real IR imaging and MR fingerprinting (MRF). METHODS: Twenty-four patients with a suspicion of endolymphatic hydrops were scanned at pre-administration and at 10 min, 4 and 24 h post-IV-SD-GBCA. 3D-real IR images and MRF at the level of the internal auditory canal were obtained. The signal intensity on the 3D-real IR image of the cerebrospinal fluid (CSF) in the cerebellopontine angle cistern (CPA), Sylvian fissure (Syl), lateral ventricle (LV), and cochlear perilymph (CPL) was measured. The T1 and T2 values of cerebellar gray (GM) and white matter (WM) were measured using MRF. Each averaged value at the various time points was compared using an analysis of variance. RESULTS: The signal intensity on the 3D-real IR image in each CSF region peaked at 4 h, and was decreased significantly by 24 h (P< 0.05). All patients had a maximum signal intensity at 4 h in the CPA, and Syl. The mean CPL signal intensity peaked at 4 h and decreased significantly by 24 h (P < 0.05). All patients but two had a maximum signal intensity at 4 h. Regarding the T1 value in the cerebellar WM and GM, the T1 value at 10 min post-IV-GBCA was significantly decreased compared to the pre-contrast scan, but no significant difference was observed at the other time points. There was no significant change in T2 in the gray or white matter at any of the time points. CONCLUSION: Time course of GBCA after IV-SD-GBCA could be evaluated by 3D-real IR imaging in CSF spaces and in the brain by MRF.

DOI： 10.2463/mrms.mp.2020-0030

Increased Dendritic Orientation Dispersion in the Left Occipital Gyrus is Associated with Atypical Visual Processing in Adults with Autism Spectrum Disorder Reviewed International journal

Kiwamu Matsuoka, Manabu Makinodan, Soichiro Kitamura, Masato Takahashi, Hiroaki Yoshikawa, Fumihiko Yasuno, Rio Ishida, Naoko Kishimoto, Yuka Yasuda, Ryota Hashimoto, Toshiaki Taoka, Toshiteru Miyasaka, Kimihiko Kichikawa, Toshifumi Kishimoto

Cerebral Cortex Vol. 30 ( 11 ) page： 5617 - 5625 2020.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Oxford University Press (OUP)

<title>Abstract</title>
In autism spectrum disorder (ASD), the complexity-specific hypothesis explains that atypical visual processing is attributable to selective functional changes in visual pathways. We investigated dendritic microstructures and their associations with functional connectivity (FC). Participants included 28 individuals with ASD and 29 typically developed persons. We explored changes in neurite orientation dispersion and density imaging (NODDI) and brain areas whose FC was significantly correlated with NODDI parameters in the explored regions of interests. Individuals with ASD showed significantly higher orientation dispersion index (ODI) values in the left occipital gyrus (OG) corresponding to the secondary visual cortex (V2). FC values between the left OG and the left middle temporal gyrus (MTG) were significantly negatively correlated with mean ODI values. The mean ODI values in the left OG were significantly positively associated with low registration of the visual quadrants of the Adolescent/Adult Sensory Profile (AASP), resulting in a significant positive correlation with passive behavioral responses of the AASP visual quadrants; additionally, the FC values between the left OG and the left MTG were significantly negatively associated with reciprocal social interaction. Our results suggest that abnormal V2 dendritic arborization is associated with atypical visual processing by altered intermediation in the ventral visual pathway.

DOI： 10.1093/cercor/bhaa121

Neurofluid Dynamics and the Glymphatic System: A Neuroimaging Perspective. International journal

Toshiaki Taoka, Shinji Naganawa

Korean journal of radiology Vol. 21 ( 11 ) page： 1199 - 1209 2020.11

Language：English Publishing type：Research paper (scientific journal)

The glymphatic system hypothesis is a concept describing the clearance of waste products from the brain. The term "glymphatic system" combines the glial and lymphatic systems and is typically described as follows. The perivascular space functions as a conduit that drains cerebrospinal fluid (CSF) into the brain parenchyma. CSF guided to the perivascular space around the arteries enters the interstitium of brain tissue via aquaporin-4 water channels to clear waste proteins into the perivascular space around the veins before being drained from the brain. In this review, we introduce the glymphatic system hypothesis and its association with fluid dynamics, sleep, and disease. We also discuss imaging methods to evaluate the glymphatic system.

DOI： 10.3348/kjr.2020.0042

Aging Impacts the Overall Connectivity Strength of Regions Critical for Information Transfer Among Brain Networks

Epifanio Bagarinao, Hirohisa Watanabe, Satoshi Maesawa, Daisuke Mori, Kazuhiro Hara, Kazuya Kawabata, Noritaka Yoneyama, Reiko Ohdake, Kazunori Imai, Michihito Masuda, Takamasa Yokoi, Aya Ogura, Toshiaki Taoka, Shuji Koyama, Hiroki C. Tanabe, Masahisa Katsuno, Toshihiko Wakabayashi, Masafumi Kuzuya, Minoru Hoshiyama, Haruo Isoda, Shinji Naganawa, Norio Ozaki, Gen Sobue

Frontiers in Aging Neuroscience Vol. 12 page： 592469 2020.10

Change of White Matter Integrity in Children With Hematopoietic Stem Cell Transplantation. International journal

Yoko Sakaguchi, Jun Natsume, Hiroyuki Kidokoro, Masaharu Tanaka, Yu Okai, Yuji Ito, Hiroyuki Yamamoto, Atsuko Ohno, Tomohiko Nakata, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka, Hideki Muramatsu, Shinji Naganawa, Yoshiyuki Takahashi

Pediatric neurology Vol. 111 page： 78 - 84 2020.10

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Advances in hematopoietic stem cell transplantation have improved the survival rate of malignant diseases and congenital immunodeficiencies. It has become important to assess long-term complications in survivors. To assess neurological abnormalities in children treated by transplantation, diffusion tensor imaging was performed. METHODS: Forty children who underwent head diffusion tensor imaging before and after their first transplantation were enrolled. Patients with brain lesions on conventional MRI were excluded. Fractional anisotropy and mean diffusivity were compared between patients and 28 control subjects using tract-based spatial statistics. The Strengths and Difficulties Questionnaire was administered as a behavioral evaluation after transplantation, and diffusion tensor images of patients with and without behavioral abnormalities were compared. RESULTS: The age of patients and controls was 0 to 19 years and 0 to 16 years, respectively. The date of diffusion tensor imaging was 10 to 57 days before and 40 to 153 days after transplantation. Tract-based spatial statistics showed fractional anisotropy reduction in widespread white matter in patients before and after transplantation. Mean diffusivity was high before transplantation and normalized after transplantation. Analysis comparing before and after hematopoietic stem cell transplantation shows no difference in fractional anisotropy and a higher mean diffusivity before hematopoietic stem cell transplantation. In patients with behavioral abnormalities, low fractional anisotropy and high mean diffusivity remained after transplantation. CONCLUSIONS: Longitudinal diffusion tensor imaging showed white matter abnormalities in children without conventional MRI abnormalities, which were related to behavioral problems after transplantation. Diffusion tensor imaging is useful for behavioral assessment in children undergoing transplantation.

DOI： 10.1016/j.pediatrneurol.2020.06.008

特集時系列から学ぶ中枢神経疾患の画像診断-MR Retroscopy- Ⅳ.脊髄　1 頸髄の変形と異常信号

田岡俊昭

画像診断 Vol. 40 ( 10 ) page： 1100 - 1103 2020.8

Changes in white matter fiber density and morphology across the adult lifespan: A cross-sectional fixel-based analysis. International journal

Shao Wei Choy, Epifanio Bagarinao, Hirohisa Watanabe, Eric Tatt Wei Ho, Satoshi Maesawa, Daisuke Mori, Kazuhiro Hara, Kazuya Kawabata, Noritaka Yoneyama, Reiko Ohdake, Kazunori Imai, Michihito Masuda, Takamasa Yokoi, Aya Ogura, Toshiaki Taoka, Shuji Koyama, Hiroki C Tanabe, Masahisa Katsuno, Toshihiko Wakabayashi, Masafumi Kuzuya, Minoru Hoshiyama, Haruo Isoda, Shinji Naganawa, Norio Ozaki, Gen Sobue

Human brain mapping Vol. 41 ( 12 ) page： 3198 - 3211 2020.8

Language：English Publishing type：Research paper (scientific journal)

White matter (WM) fiber bundles change dynamically with age. These changes could be driven by alterations in axonal diameter, axonal density, and myelin content. In this study, we applied a novel fixel-based analysis (FBA) framework to examine these changes throughout the adult lifespan. Using diffusion-weighted images from a cohort of 293 healthy volunteers (89 males/204 females) from ages 21 to 86 years old, we performed FBA to analyze age-related changes in microscopic fiber density (FD) and macroscopic fiber morphology (fiber cross section [FC]). Our results showed significant and widespread age-related alterations in FD and FC across the whole brain. Interestingly, some fiber bundles such as the anterior thalamic radiation, corpus callosum, and superior longitudinal fasciculus only showed significant negative relationship with age in FD values, but not in FC. On the other hand, some segments of the cerebello-thalamo-cortical pathway only showed significant negative relationship with age in FC, but not in FD. Analysis at the tract-level also showed that major fiber tract groups predominantly distributed in the frontal lobe (cingulum, forceps minor) exhibited greater vulnerability to the aging process than the others. Differences in FC and the combined measure of FD and cross section values observed between sexes were mostly driven by differences in brain sizes although male participants tended to exhibit steeper negative linear relationship with age in FD as compared to female participants. Overall, these findings provide further insights into the structural changes the brain's WM undergoes due to the aging process.

DOI： 10.1002/hbm.25008

Steroid-responsive recurrent tumefactive demyelination with multiple petechial hemorrhages along non-displaced medullary veins. Reviewed International journal

Takashi Tsuboi, Yumiko Harada, Masashi Suzuki, Takashi Ando, Naoki Atsuta, Fumiharu Ohka, Kazuhito Takeuchi, Toshiaki Taoka, Shigeo Ohba, Masato Nakaguro, Masato Abe, Ichiro Nakashima, Mari Yoshida, Masahisa Katsuno

Clinical neurology and neurosurgery Vol. 193 page： 105764 - 105764 2020.6

White matter microstructural changes in tuberous sclerosis: Evaluation by neurite orientation dispersion and density imaging (NODDI) and diffusion tensor images. Reviewed International journal

Toshiaki Taoka, Noriko Aida, Yuta Fujii, Kazushi Ichikawa, Hisashi Kawai, Toshiki Nakane, Rintaro Ito, Shinji Naganawa

Scientific reports Vol. 10 ( 1 ) page： 436 - 436 2020.1

Language：English Publishing type：Research paper (scientific journal)

Neurite orientation dispersion and density imaging (NODDI) is a novel diffusion method for evaluating tissue microstructure, and may provide additional information over conventional diffusion tensor imaging (DTI). We evaluated NODDI and DTI parameters in cases of tuberous sclerosis (TS) to assess microstructural changes in the white matter. Eleven cases of tuberous sclerosis and eight age-matched controls underwent NODDI and DTI. We performed qualitative analysis and tract-based spatial statistics (TBSS) analysis of the NODDI parameters (Ficv: intracellular volume fraction, Fiso: isotropic fraction, ODI: orientation dispersion index) as well as DTI parameters (MD: mean diffusivity, FA: fractional anisotropy). We also performed a correlation analysis between clinical symptoms and parameters. The qualitative analysis indicated that the Ficv had a lower value in TS cases particularly in the tubers adjacent to the white matter. The TBSS analysis showed that the TS cases had decreased Ficv in a greater area compared to the other parameters including MD. In particular, the Ficv was decreased in deep white matter, such as the superior longitudinal fascicles (SLF). The application of NODDI to TS cases revealed tissue microstructural changes, and particularly the Ficv could detect more widespread abnormalities in white matter structure compared to DTI parameters.

DOI： 10.1038/s41598-019-57306-w

Glymphatic imaging using MRI. Reviewed International journal

Toshiaki Taoka, Shinji Naganawa

Journal of magnetic resonance imaging : JMRI Vol. 51 ( 1 ) page： 11 - 24 2020.1

Language：English Publishing type：Research paper (scientific journal)

In recent years, the existence of a mass transport system in the brain via cerebrospinal fluid (CSF) or interstitial fluid (ISF) has been suggested by many studies. The glymphatic system is hypothesized to be a waste clearance system of the CSF through the perivascular and interstitial spaces in the brain. Tracer studies have primarily been used to visualize or evaluate the waste clearance system in the brain, and evidence for this system has accumulated. The initial study that identified the glymphatic system was an in vivo tracer study in mice. In that study, fluorescent tracers were injected into the cisterna magna and visualized by two-photon microscopy. MRI has also been used to evaluate glymphatic function primarily with gadolinium-based contrast agents (GBCAs) as tracers. A number of GBCA studies evaluating glymphatic function have been conducted using either intrathecal or intravenous injections. Stable isotopes, such as 17 O-labeled water, may also be used as tracers since they can be detected by MRI. In addition to tracer studies, several other approaches have been used to evaluate ISF dynamics within the brain, including diffusion imaging. Phase contrast evaluation is a powerful method for visualizing flow within the CSF space. In order to evaluate the movement of water within tissue, diffusion-weighted MRI represents another promising technique, and several studies have utilized diffusion techniques for the evaluation of the glymphatic system. This review will discuss the findings of these diffusion studies. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2020;51:11-24.

DOI： 10.1002/jmri.26892

Comprehensive Evaluation of B1+-corrected FISP-based Magnetic Resonance Fingerprinting: Accuracy, Repeatability and Reproducibility of T1 and T2 Relaxation Times for ISMRM/NIST System Phantom and Volunteers. Reviewed

Yutaka Kato, Kazushige Ichikawa, Kuniyasu Okudaira, Toshiaki Taoka, Hirokazu Kawaguchi, Katsutoshi Murata, Katsuya Maruyama, Gregor Koerzdoerfer, Josef Pfeuffer, Mathias Nittka, Shinji Naganawa

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 19 ( 3 ) page： 168 - 175 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: This study aimed to evaluate comprehensively; accuracy, repeatability and reproducibility of T1 and T2 relaxation times measured by magnetic resonance fingerprinting using B1+-corrected fast imaging with steady-state precession (FISP-MRF). METHODS: The International Society of Magnetic Resonance in Medicine/National Institute of Standards and Technology (ISMRM/NIST) phantom was scanned for 100 days, and six healthy volunteers for 5 days using a FISP-MRF prototype sequence. Accuracy was evaluated on the phantom by comparing relaxation times measured by FISP-MRF with the reference values provided by the phantom manufacturer. Daily repeatability was characterized as the coefficient of variation (CV) of the measurements over 100 days for the phantom and over 5 days for volunteers. In addition, the cross-scanner reproducibility was evaluated in volunteers. RESULTS: In the phantom study, T1 and T2 values from FISP-MRF showed a strong linear correlation with the reference values of the phantom (R2 = 0.9963 for T1; R2 = 0.9966 for T2). CVs were <1.0% for T1 values larger than 300 ms, and <3.0% for T2 values across a wide range. In the volunteer study, CVs for both T1 and T2 values were <5.0%, except for one subject. In addition, all T2 values estimated by FISP-MRF in vivo were lower than those measured with conventional mapping sequences reported in previous studies. The cross-scanner variation of T1 and T2 showed good agreement between two different scanners in the volunteers. CONCLUSION: B1+-corrected FISP-MRF showed an acceptable accuracy, repeatability and reproducibility in the phantom and volunteer studies.

DOI： 10.2463/mrms.mp.2019-0016

The Space between the Pial Sheath and the Cortical Venous Wall May Connect to the Meningeal Lymphatics. Reviewed

Shinji Naganawa, Rintaro Ito, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 19 ( 1 ) page： 1 - 4 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

We currently obtain pre- and post-contrast enhanced whole brain 3D-real inversion recovery images for the evaluation of endolymphatic hydrops. We noticed that the space between the pial sheath surrounding the cortical veins and the cortical venous wall is enhanced and this enhancement seems to connect to the meningeal lymphatics along superior sagittal sinus. This new anatomical concept regarding the outflow from the glymphatic system might be important for the future research in neuroscience.

DOI： 10.2463/mrms.bc.2019-0099

Detection of IV-gadolinium Leakage from the Cortical Veins into the CSF Using MR Fingerprinting. Reviewed

Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka, Hirokazu Kawaguchi, Katsuya Maruyama, Katsutoshi Murata, Gregor Körzdörfer, Josef Pfeuffer, Mathias Nittka, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 19 ( 2 ) page： 141 - 146 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: It has been reported that leakage of intravenously administered gadolinium-based contrast agents (IV-GBCAs) into the cerebrospinal fluid (CSF) from the cortical veins even in healthy subjects can be detected using a highly sensitive pulse sequence such as heavily T2-weighted 3D fluid-attenuated inversion recovery and 3D-real inversion recovery (IR). The purpose of this study was to evaluate the feasibility of MR fingerprinting to detect GBCA leakage from the cortical veins after IV-GBCA. MATERIALS: Fourteen patients with suspected endolymphatic hydrops (EH) who received a single dose of IV-GBCA (39-79 years old) were included. The real IR images as well as MR fingerprinting images were obtained at 4 h after IV-GBCA. T1 and T2 values were obtained using MR fingerprinting and analyzed in ROIs covering intense GBCA leakage, and non-leakage areas of the CSF as determined on real IR images. The scan time for real IR imaging was 10 min and that for MR fingerprinting was 41 s. RESULTS: The mean T1 value of the ROI in the area of GBCA leakage was 2422 ± 261 ms and that in the non-leakage area was 3851 ± 235 ms (P < 0.01). There was no overlap between the T1 values in the area of GBCA leakage and those in the non-leakage area.The mean T2 value in the area of GBCA leakage was 319 ± 90 ms and that in the non-leakage area was 670 ± 166 ms (P < 0.01). There was some overlap between the T2 values in the area of GBCA leakage and those in the non-leakage area. CONCLUSION: Leaked GBCA from the cortical veins into the surrounding CSF can be detected using MR fingerprinting obtained in <1 min.

DOI： 10.2463/mrms.mp.2019-0048

Confirmation of Age-dependence in the Leakage of Contrast Medium around the Cortical Veins into Cerebrospinal Fluid after Intravenous Administration of Gadolinium-based Contrast Agent. Reviewed

Shinji Naganawa, Rintaro Ito, Hisashi Kawai, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 19 ( 4 ) page： 375 - 381 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: It has been reported previously that intravenously administered gadolinium-based contrast agent (GBCA) leaks into the subarachnoid space around the cortical veins at 4 h after injection in all old people over 37 years, but not in younger people up to 37 years of age in 3D-real IR images. The purpose of this study was to investigate whether there was a strict threshold of 37 years of age for the leakage of the GBCA into the subarachnoid space. METHODS: The subjects included 190 patients, that were scanned for 3D-real IR images at 4 hours after intravenous injection of GBCA as a diagnostic test for endolymphatic hydrops. The patient's age ranged from 14 to 81 years. Two experienced neuroradiologists evaluated the images to determine whether the GBCA leakage around the cortical veins was positive or negative. Any discrepancies between the two observers were discussed and a consensus was obtained.A Mann-Whitney U test and receiver operating characteristic (ROC) curve analysis were used to compare the positive and the negative group and to set the age cut-off value for the prediction of GBCA leakage. RESULTS: The GBCA leakage around the cortical veins was negative in 35 patients and positive in 155 patients. The average age was 33 ± 11 years in the negative group, and 55 ± 12 years in the positive group (P < 0.01). In the ROC analysis for the age and leakage of the GBCA, an area under the curve was 0.905 and the cut-off age was 37.317 years (sensitivity of 0.942 and specificity of 0.771). CONCLUSION: Intravenously administered GBCA leaks into the subarachnoid space around the cortical veins in most patients over 37 years of age. However, it should be noted that it can be found occasionally in patients under 37 years of age.

DOI： 10.2463/mrms.mp.2019-0182

Computer-assisted cognitive remediation therapy for patients with schizophrenia induces microstructural changes in cerebellar regions involved in cognitive functions. Reviewed International journal

Matsuoka K, Morimoto T, Matsuda Y, Yasuno F, Taoka T, Miyasaka T, Yoshikawa H, Takahashi M, Kitamura S, Kichikawa K, Kishimoto T

Psychiatry research. Neuroimaging Vol. 292 page： 41 - 46 2019.10

Language：English Publishing type：Research paper (scientific journal)

Previous studies have reported that cognitive remediation therapy (CRT) improves cognitive deficits in patents with schizophrenia. However, few studies have focused on the underlying structural alterations in the brain following Vocational Cognitive Ability Training by the Japanese Cognitive Rehabilitation Program for Schizophrenia (VCAT-J). In this study, we analyzed changes in diffusion tensor imaging parameters in 31 patients with schizophrenia after 12 weeks of intervention consisting of standard treatment alone or standard treatment plus VCAT-J, in order to determine the effect of the latter on white matter microstructural plasticity. Cognitive function was evaluated using the Japanese version of the Brief Assessment of Cognition in Schizophrenia (BACS-J) scale. The CRT group exhibited significant improvements in verbal fluency and composite BACS-J scores, relative to the treatment-as-usual (TAU) group. In addition, the CRT group exhibited significantly increased fractional anisotropy (FA) values, along with significantly decreased radial (RD) and mean diffusivity (MD) values, in the posterior lobe of the left cerebellum. Changes in RD and MD values were negatively correlated with changes in BACS-J composite scores. These suggest that VCAT-J might mediate improvements in myelin sheath composition in the posterior lobe of the left cerebellum, which may have been associated with improvements in cognitive function.

DOI： 10.1016/j.pscychresns.2019.09.001

Reorganization of brain networks and its association with general cognitive performance over the adult lifespan. Reviewed International journal

Epifanio Bagarinao, Hirohisa Watanabe, Satoshi Maesawa, Daisuke Mori, Kazuhiro Hara, Kazuya Kawabata, Noritaka Yoneyama, Reiko Ohdake, Kazunori Imai, Michihito Masuda, Takamasa Yokoi, Aya Ogura, Toshiaki Taoka, Shuji Koyama, Hiroki C Tanabe, Masahisa Katsuno, Toshihiko Wakabayashi, Masafumi Kuzuya, Norio Ozaki, Minoru Hoshiyama, Haruo Isoda, Shinji Naganawa, Gen Sobue

Scientific reports Vol. 9 ( 1 ) page： 11352 - 11352 2019.8

Language：English Publishing type：Research paper (scientific journal)

Healthy aging is associated with structural and functional changes in the brain even in individuals who are free of neurodegenerative diseases. Using resting state functional magnetic resonance imaging data from a carefully selected cohort of participants, we examined cross sectional changes in the functional organization of several large-scale brain networks over the adult lifespan and its potential association with general cognitive performance. Converging results from multiple analyses at the voxel, node, and network levels showed widespread reorganization of functional brain networks with increasing age. Specifically, the primary processing (visual and sensorimotor) and visuospatial (dorsal attention) networks showed diminished network integrity, while the so-called core neurocognitive (executive control, salience, and default mode) and basal ganglia networks exhibited relatively preserved between-network connections. The visuospatial and precuneus networks also showed significantly more widespread increased connectivity with other networks. Graph analysis suggested that this reorganization progressed towards a more integrated network topology. General cognitive performance, assessed by Addenbrooke's Cognitive Examination-Revised total score, was positively correlated with between-network connectivity among the core neurocognitive and basal ganglia networks and the integrity of the primary processing and visuospatial networks. Mediation analyses further indicated that the observed association between aging and relative decline in cognitive performance could be mediated by changes in relevant functional connectivity measures. Overall, these findings provided further evidence supporting widespread age-related brain network reorganization and its potential association with general cognitive performance during healthy aging.

DOI： 10.1038/s41598-019-47922-x

Increased signal intensity of low-concentration gadolinium contrast agent by longer repetition time in heavily T2-weighted-3D-FLAIR. Reviewed

Yutaka Kato, Kiminori Bokura, Toshiaki Taoka, Shinji Naganawa

Japanese journal of radiology Vol. 37 ( 5 ) page： 431 - 435 2019.5

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: To apply for detecting low-concentration gadolinium contrast agent (Gd), such as those in the perilymph and cerebrospinal fluid (CSF) at 4 h after intravenous administrations (IV), we tried to clarify the degree of increased signal intensity (SI) of low-concentration Gd by longer repetition time (TR) in heavily T2-weighed 3D-FLAIR. MATERIALS AND METHODS: A phantom was designed using Gd diluted with saline at 0.250-0.008 mM and obtained images by varying the TR from 9000 to 16,000. We measured the SI of five slices for each concentration and compared the mean SI (SImean) values. Normalized SI (SInorm) values, defined as the SImean value of each TR divided by the SImean value of 9000-ms TR for each concentration were compared. RESULTS: Longer TR increased the SImean values in all solutions. In the 0.250 mM solution, the SImean value of 16,000-ms TR was 1.07-times greater than that of 9000-ms TR. In contrast, the SImean value of 16,000-ms TR was 1.67-times greater than that of 9000-ms TR in 0.008 mM solution. CONCLUSION: SI increased with longer TR and lower Gd concentration. Thus, longer TR was useful in detecting low-concentration Gd, such as those in the perilymph and CSF at 4 h after IV.

DOI： 10.1007/s11604-019-00828-0

特集症候別画像診断プロトコル病期診断および再発チェック　頸動脈プラークイメージ[MRI]

田岡俊昭

臨床画像 Vol. 35 ( 13 ) page： 120 - 121 2019.4

特集症候別画像診断プロトコル 3T MRI独特のシーケンス　MRS

田岡俊昭

臨床画像 Vol. 35 ( 13 ) page： 156 - 158 2019.4

特集症候別画像診断プロトコル 3T MRI独特のシーケンス　拡散テンソル画像

田岡俊昭

臨床画像 Vol. 35 ( 13 ) page： 159 - 161 2019.4

Can low b value diffusion weighted imaging evaluate the character of cerebrospinal fluid dynamics? Reviewed

Toshiaki Taoka, Shinji Naganawa, Hisashi Kawai, Toshiki Nakane, Katsutoshi Murata

Japanese journal of radiology Vol. 37 ( 2 ) page： 135 - 144 2019.2

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: We aimed to investigate whether low b value diffusion-weighted imaging (DWI) can show the change of cerebrospinal fluid (CSF) dynamics. MATERIALS AND METHODS: The subjects of this retrospective study consisted of patients with ventricular dilatation (n = 50) and controls (n = 50). The CSF signal intensity on the b = 500 s/mm2 DWI was evaluated by a scoring method in the lateral, 3rd and 4th ventricles, the cerebral sulci and the Sylvian fissure. The signal void findings adjacent to the septum pellucidum were also evaluated. RESULTS: The CSF signal intensities were significantly less in lateral ventricle and 3rd ventricle of the ventricular dilatation subjects. In controls, the score for the signal void in the Sylvian fissure showed a significant positive correlation with age. However, other areas did not show a significant correlation with age. The appearance of the characteristic signal void adjacent to the septum pellucidum showed a significant correlation with ventricular dilatation. CONCLUSION: Our current study suggests that the CSF signal intensity on the b = 500 s/mm2 DWI may show the changes in CSF dynamics and might be useful to evaluate the overlook of CSF dynamics.

DOI： 10.1007/s11604-018-0790-8

Age Dependence of Gadolinium Leakage from the Cortical Veins into the Cerebrospinal Fluid Assessed with Whole Brain 3D-real Inversion Recovery MR Imaging. Reviewed

Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 18 ( 2 ) page： 163 - 169 2019

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: It has been reported that intravenously administered gadolinium-based contrast agents (IV-GBCAs) leak into the cerebrospinal fluid (CSF) even in healthy subjects. The purpose of this study was to evaluate GBCA leakage from the cortical veins in patients with delayed imaging after IV-GBCA. MATERIALS AND METHODS: There are two parts of retrospective study. In the first part, we reviewed six patients with suspected endolymphatic hydrops (EH) who received a single dose of IV-GBCA (37-58 years old). The 3D-real inversion recovery images were obtained prior to the contrast administration as well as 5 min and 4 h after IV-GBCA. Leakage from the cortical veins to the CSF was graded as positive if enhancement around the cortical veins at 5 min was observed and had further spread into the CSF at 4 h after IV-GBCA.In the second part of this study, we reviewed 21 patients with suspected EH (17-69 years old). Images were obtained only at 4 h after IV-GBCA. The number of slices (NOS) with a positive GBCA leakage from the cortical veins was counted. The correlation of the NOS with age, gender, and degree of EH was evaluated by Spearman's rank correlation coefficient. RESULTS: In the first part of the study, the GBCA leakage from the cortical veins was positive in all patients. In the second part of the study, the GBCA leakage from the cortical veins was seen in all older patients (above 37 years old), but not in the five younger patients (younger than 37 years old). The NOS correlated significantly only with age (r = 0.755, P < 0.01), but not with gender or degree of EH. CONCLUSION: IV-GBCA leaks from the cortical veins into the surrounding CSF. The leakiness of the cortical veins significantly correlated with age, but not with gender or degree of EH.

DOI： 10.2463/mrms.mp.2018-0053

Inter-individual Comparison of Gadobutrol and Gadoteridol Tissue Time-intensity Profiles for Dynamic Susceptibility Contrast Perfusion MR Imaging. Reviewed

Masahiro Yamada, Toshiaki Taoka, Ai Kawaguchi, Kenji Yasuda, Yasushi Niinomi, Yoichi Ohashi, Takahito Okuda, Shinji Naganawa

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 18 ( 1 ) page： 75 - 81 2019

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: Gadobutrol is a gadolinium-based contrast material (GBCM) with a high concentration of gadolinium and high relaxivity. Our purpose was to evaluate the signal intensity profiles in brain tissue for the bolus width and degree of signal change after bolus injection using an echo planar dynamic susceptibility contrast (DSC) sequence. We compared gadobutrol to gadoteridol using various injection speeds and saline flush volumes. METHODS: We studied 97 patients who underwent brain MRI. Datasets for perfusion studies were acquired using a 3T scanner with an echo planar imaging (EPI) sequence. The injection protocols were set up with combinations of injection speed and saline flush volume for both gadobutrol and gadoteridol. The full width at half maximum (FWHM) and the maximum signal change ratio (SCRmax) of the time intensity curves were measured. RESULTS: The FWHM did not show a statistically significant difference according to injection speed, flush volume, or type of GBCM. The SCRmax showed a greater change with a faster injection speed, larger saline flush, and gadobutrol administration. The difference between gadobutrol and gadoteridol became smaller with a faster injection speed and a larger saline flush. CONCLUSION: The maximum signal drop was larger with gadobutrol when the injection speed was slow and the saline flush was small. Thus, gadobutrol may be useful to obtain a better profile for DSC perfusion MRI in conditions requiring a slower injection speed and/or a smaller volume of saline flush.

DOI： 10.2463/mrms.mp.2017-0172

Improved 3D-real Inversion Recovery: A Robust Imaging Technique for Endolymphatic Hydrops after Intravenous Administration of Gadolinium. Reviewed

Shinji Naganawa, Hisashi Kawai, Toshiaki Taoka, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 18 ( 1 ) page： 105 - 108 2019

PREDICTION OF INTRACRANIAL ARTERIAL STENOSIS PROGRESSION IN PATIENTS WITH MOYAMOYA VASCULOPATHY: CONTRAST-ENHANCED HIGH-RESOLUTION MAGNETIC RESONANCE VESSELWALL IMAGING

Muraoka S., Araki Y., Taoka T., Kawai H., Okamoto S., Uda K., Ota S., Naganawa S., Wakabayashi T.

INTERNATIONAL JOURNAL OF STROKE Vol. 13 page： 32 - 32 2018.10

Corpus callosal involvement is correlated with cognitive impairment in multiple system atrophy. Reviewed International journal

Kazuhiro Hara, Hirohisa Watanabe, Epifanio Bagarinao, Kazuya Kawabata, Noritaka Yoneyama, Reiko Ohdake, Kazunori Imai, Michihito Masuda, Takamasa Yokoi, Aya Ogura, Takashi Tsuboi, Mizuki Ito, Naoki Atsuta, Hisayoshi Niwa, Toshiaki Taoka, Satoshi Maesawa, Shinji Naganawa, Masahisa Katsuno, Gen Sobue

Journal of neurology Vol. 265 ( 9 ) page： 2079 - 2087 2018.9

Language：English Publishing type：Research paper (scientific journal)

OBJECTIVE: We examined the anatomical involvement related to cognitive impairment in patients with multiple system atrophy (MSA). METHODS: We examined 30 patients with probable MSA and 15 healthy controls. All MSA patients were assessed by the Unified MSA-Rating scale and Addenbrooke's Cognitive Examination-Revised (ACE-R). We classified 15 MSA patients with ACE-R scores > 88 as having normal cognition (MSA-NC) and 15 with scores ≤ 88 as having cognitive impairment (MSA-CI). All subjects underwent 3 T MRI scanning and were investigated using voxel-based morphometry and diffusion tensor imaging. RESULTS: Both the MSA-NC and MSA-CI patients exhibited cerebellar but not cerebral atrophy in voxel-based morphometry compared to controls. In contrast, tract-based spatial statistics revealed widespread and significantly decreased fractional anisotropy (FA) values, as well as increased mean diffusivity, radial diffusivity, and axial diffusivity in both the cerebrum and cerebellum in MSA-CI patients compared to controls. MSA-NC patients also exhibited similar involvement of the cerebellum but less extensive involvement of the cerebrum compared with the MSA-CI patients. In particular, FA values in MSA-CI patients were significantly decreased in the anterior part of the left corpus callosum compared with those in MSA-NC patients. The mean FA values in the left anterior part of the corpus callosum were significantly correlated with total ACE-R scores and subscores (memory, fluency, and language) in MSA patients. CONCLUSIONS: Decreased FA values in the anterior corpus callosum showed a significant correlation with cognitive impairment in MSA.

DOI： 10.1007/s00415-018-8923-7

Impact of the Glymphatic System on the Kinetic and Distribution of Gadodiamide in the Rat Brain: Observations by Dynamic MRI and Effect of Circadian Rhythm on Tissue Gadolinium Concentrations. Reviewed International coauthorship International journal

Toshiaki Taoka, Gregor Jost, Thomas Frenzel, Shinji Naganawa, Hubertus Pietsch

Investigative radiology Vol. 53 ( 9 ) page： 529 - 534 2018.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Ovid Technologies (Wolters Kluwer Health)

OBJECTIVES: The glymphatic system is a recently hypothesized waste clearance system of the brain in which perivascular space constitutes a pathway similar to the lymphatic system in other body regions. Sleep and anesthesia are reported to influence the activity of the glymphatic system. Because rats are nocturnal animals, the glymphatic system is expected to be more active during the day. We attempted to elucidate the influence of the glymphatic system for intravenously injected gadodiamide in the rat brain by 2 experiments. One was a magnetic resonance imaging (MRI) experiment to evaluate the short-term dynamics of signal intensity changes after gadodiamide administration. The other was a quantification experiment to evaluate the concentration of retained gadolinium within the rat brain after repeated intravenous administration of gadodiamide at different times of day and levels of anesthesia. MATERIALS AND METHODS: The imaging experiment was performed on 6 rats that received an intravenous injection of gadodiamide (1 mmol/kg) and dynamic MRI for 3 hours at 2.4-minute intervals. The time course of the signal intensity changes was evaluated for different brain structures. The tissue quantification experiment was performed on 24 rats divided into 4 groups by injection time (morning, late afternoon) and anesthesia (none, short, long) during administration. All animals received gadodiamide (1.8 mmol/kg, 8 times over 2 weeks). Gadolinium concentration of dissected brain tissues was quantified 5 weeks after the last administration by inductively coupled plasma mass spectrometry. RESULTS: In the imaging experiment, muscle and the fourth ventricle showed an instantaneous signal intensity increase immediately after gadodiamide injection. The signal curve of the cerebral cortex and deep cerebellar nuclei reached the peak signal intensity later than the fourth ventricle but earlier than that of the prepontine cistern. In the gadolinium quantification experiment, the concentration in the group with the morning injection showed a significantly lower concentration than the late afternoon injection group. The lowest tissue gadolinium concentrations were found in the groups injected in the morning during long anesthesia. CONCLUSIONS: Instantaneous transition of gadodiamide from blood to cerebrospinal fluid was indicated by dynamic MRI. The gadodiamide distribution to the cerebral cortex and deep cerebellar nuclei seemed to depend on both blood flow and cerebrospinal fluid. This confirms previous studies indicating that the cerebrospinal fluid is one potential pathway of gadolinium-based contrast agent entry into the brain. For the distribution and clearance of the gadodiamide from brain tissue, involvement of the glymphatic system seemed to be indicated in terms of the influence of sleep and anesthesia.

DOI： 10.1097/RLI.0000000000000473

Prediction of Intracranial Arterial Stenosis Progression in Patients with Moyamoya Vasculopathy: Contrast-Enhanced High-Resolution Magnetic Resonance Vessel Wall Imaging. Reviewed International journal

Shinsuke Muraoka, Yoshio Araki, Toshiaki Taoka, Hisashi Kawai, Sho Okamoto, Kenji Uda, Shinji Ota, Shinji Naganawa, Toshihiko Wakabayashi

World neurosurgery Vol. 116 page： E1114 - E1121 2018.8

Language：English Publishing type：Research paper (scientific journal)

OBJECTIVE: Moyamoya vasculopathy (MMV) is characterized by progressive stenosis of the intracranial arteries. MMV currently has no curative treatments, and cerebral ischemia and hemorrhage are the major outcomes. Evaluation of the stroke risk of each patient resulting from the progression of intracranial arterial stenosis is clinically important. METHODS: We prospectively reviewed patients with intracranial arterial stenosis and already diagnosed MMV. High-resolution magnetic resonance imaging using contrast agent is the novel vessel wall imaging (VWI) technique for directly evaluating vascular walls and intracranial artery disease. All patients underwent high-resolution vessel wall imaging and magnetic resonance angiography at the time of registration, and they underwent follow-up magnetic resonance angiography. The Fisher exact test was used to assess associations between the degrees of wall enhancement and between stable and progressive intracranial arterial stenosis. RESULTS: A total of 24 patients (17 female; mean age, 36.1 ± 16.8 years; range 3-67 years) with MMV were consecutively recruited to this study. Progression of stenosis was shown in 6 lesions (66.6%) on strong enhancement, 2 lesions (12.5%) on mild enhancement, and 1 lesion (4.3%) on lack of enhancement. Arterial vessel wall enhancement in MMV patients correlated closely with progression of intracranial arterial stenosis (P = 0.002). CONCLUSIONS: Arterial vessel wall enhancement in MMV patients was closely related to progression of intracranial arterial stenosis. Strong enhancement of the intracranial vessel wall was associated with intracranial arterial stenosis progression, and lack of enhancement correlated with the stability of intracranial arterial stenosis.

DOI： 10.1016/j.wneu.2018.05.181

Imaging Differences between Neuromyelitis Optica Spectrum Disorders and Multiple Sclerosis: A Multi-Institutional Study in Japan Reviewed

A guide to identification and selection of axial planes in magnetic resonance imaging of the brain. Reviewed International coauthorship International journal

Otake S, Taoka T, Maeda M, Yuh WT

The neuroradiology journal Vol. 31 ( 4 ) page： 336 - 344 2018.8

Language：English Publishing type：Research paper (scientific journal) Publisher：{SAGE} Publications

For brain magnetic resonance (MR) examination, three-dimensional imaging is commonly performed. Radiologists need to know the appropriate imaging angle for viewing. We present six imaging angles for the axial images. Each angle is determined by the reference line. The landmarks on the midsagittal MR image to determine the angle of the reference lines are as follows: the supraorbito-meatal line (the center of the mammillary body and the fastigium of the fourth ventricle), the orbito-meatal (OM) line (the center of the mammillary body and the most posterior point of the cerebellar tentorium), the Talairach anterior commissure (AC)-posterior commissure (PC) line (the superior edge of the AC and the inferior edge of the PC), the Schaltenbrand AC-PC line (the center of the AC and the center of the PC), the subcallosal line (the inferior border of the genu and the inferior border of the splenium of the corpus callosum), Reid's baseline (the center of the pituitary gland and the most posterior point of the cerebellar tentorium) and the brainstem vertical line (the line perpendicular to the posterior border of the brainstem). The AC-PC line is most commonly used in MR examination. The OM line is most commonly used in computed tomography examination. The supraorbito-meatal line is recommended for avoiding irradiation to the orbit. In cases of multiple sclerosis, the subcallosal line is recommended in the guidelines. For lesions in the orbital cavity, paranasal cavity or skull base, Reid's baseline is useful. For cases of brainstem lesions, the brainstem vertical line is useful.

DOI： 10.1177/1971400918769911

H. Tatekawa, S. Sakamoto, M. Hori, Y. Kaichi, A. Kunimatsu, K. Akazawa, T. Miyasaka, H. Oba, T. Okubo, K. Hasuo, K. Yamada, T. Taoka, S. Doishita, T. Shimono, Y. Miki

American Journal of Neuroradiology Vol. 39 ( 7 ) page： 1239 - 1247 2018.7

特集知っておきたいMRI画像診断のコツ中枢神経　頭部外傷

宮坂俊輝, 田岡俊昭

臨床画像 Vol. 34 ( 13 ) page： 63 - 71 2018.4

Computer-assisted cognitive remediation therapy increases hippocampal volume in patients with schizophrenia: A randomized controlled trial Reviewed International journal

Tsubasa Morimoto, Yasuhiro Matsuda, Kiwamu Matsuoka, Fumihiko Yasuno, Emi Ikebuchi, Hiroyuki Kameda, Toshiaki Taoka, Toshiteru Miyasaka, Kimihiko Kichikawa, Toshifumi Kishimoto

BMC Psychiatry Vol. 18 ( 1 ) page： 83 - 83 2018.3

Language：English Publishing type：Research paper (scientific journal) Publisher：BioMed Central Ltd.

Background: Cognitive remediation therapy (CRT) effectively reduces neurocognitive impairment in patients with schizophrenia, but few studies have used structural neuroimaging methods to assess its neuroanatomical effects. We investigated these effects, as well as the association between changes in cortical volume and neurocognitive performance. Method: Between August 2013 and September 2016, we performed a randomized controlled study comprising a CRT group (16 individuals) and a treatment-as-usual (TAU) group (15 individuals) of patients with schizophrenia. CRT participants engaged in twice-weekly computer-assisted CRT sessions and weekly group meetings for 12 weeks. T1-weighted magnetic resonance imaging was performed before and after the intervention period, and whole-brain voxel-based morphometric analysis was used to detect significant cortical gray matter volume changes. We also assessed the correlation between cortical volume changes and CRT-derived neurocognitive improvements. Results: The CRT group exhibited significantly greater improvements than the TAU group in verbal fluency (P = 0.012) and global cognitive scores (P = 0.049). The CRT group also exhibited significantly greater increases in right hippocampal volume than the TAU group (P &lt
0.001). Changes in verbal fluency scores and right hippocampal volumes were positively correlated (r = 0.53, P = 0.001). Conclusion: We found that CRT significantly increased right hippocampal volumes and that these enhancements were positively correlated with changes in verbal fluency scores. Our results indicate that CRT induces cognitive improvement through hippocampal plasticity.

DOI： 10.1186/s12888-018-1667-1

特集脳脊髄液動態のすべて脳脊髄液による老廃物のクリアランス−glymphaticシステム−

頭部の鑑別診断のポイント第7章血管の異常　2. 血管壁の異常を示す疾患の鑑別

田岡俊昭

画像診断 Vol. 38 ( 4 ) page： s152 - s159 2018.3

田岡俊昭, 長縄慎二

画像診断 Vol. 38 ( 3 ) page： 268 - 276 2018.2

Appearance of the Organum Vasculosum of the Lamina Terminalis on Contrast-enhanced MR Imaging. Reviewed

Shinji Naganawa, Toshiaki Taoka, Hisashi Kawai, Masahiro Yamazaki, Kojiro Suzuki

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 17 ( 2 ) page： 132 - 137 2018

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: Circumventricular organs (CVOs) lack a blood brain barrier and are also called "brain windows". Among CVOs, the organum vasculosum of the lamina terminalis (OVLT) is an osmotic regulator involved in the release of vasopressin. In a previous study of healthy subjects, it was reported that contrast enhancement in the OVLT can be recognized in only 34% of 3 Tesla thin slice contrast-enhanced T1-weighted images. The purpose of this study was to evaluate the leakage of gadolinium contrast from the OVLT in healthy subjects using heavily T2-weighted three dimensional-fluid attenuated inversion recovery (3D-FLAIR) (HF) imaging. METHODS: Eight healthy male subjects were included in this study. A standard dose (0.1 mmol/kg) of gadoteridol was intravenously administered. Magnetic resonance cisternography (MRC) and HF were obtained before and 0.5, 1.5, 3, 4.5 and 6 h after the injection. Enhancement of the OVLT including the surrounding cerebral spinal fluid (CSF) was measured by manually drawing a rectangular ROI centered on the OVLT. The ROI was copied to the HF image and the signal intensity was measured. The signal intensity ratio (SIR) was obtained by dividing the signal intensity value of the OVLT ROI by that of the midbrain. RESULTS: The differences between the mean SIR at pre-contrast and those at 0.5, 1.5, 3, 4.5, and 6 h were significant (P < 0.05). The mean SIR at 0.5 h was higher than those at all other time points (P < 0.05). CONCLUSION: Using HF imaging, enhancement around the OVLT was observed in all subjects at 0.5 h after intravenous administration of single dose gadoteridol.

DOI： 10.2463/mrms.mp.2017-0088

Differences in Signal Intensity and Enhancement on MR Images of the Perivascular Spaces in the Basal Ganglia versus Those in White Matter. Reviewed

Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 17 ( 4 ) page： 301 - 307 2018

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

PURPOSE: To elucidate differences between the perivascular space (PVS) in the basal ganglia (BG) versus that found in white matter (WM) using heavily T2-weighted FLAIR (hT2-FL) in terms of 1) signal intensity on non-contrast enhanced images, and 2) the degree of contrast enhancement by intravenous single dose administration of gadolinium based contrast agent (IV-SD-GBCA). MATERIALS AND METHODS: Eight healthy men and 13 patients with suspected endolymphatic hydrops were included. No subjects had renal insufficiency. All subjects received IV-SD-GBCA. MR cisternography (MRC) and hT2-FL images were obtained prior to and 4 h after IV-SD-GBCA. The signal intensity of the PVS in the BG, subinsular WM, and the cerebrospinal fluid (CSF) in Ambient cistern (CSFAC) and CSF in Sylvian fissure (CSFSyl) was measured as well as that of the thalamus. The signal intensity ratio (SIR) was calculated by dividing the intensity by that of the thalamus. We used 5% as a threshold to determine the significance of the statistical test. RESULTS: In the pre-contrast scan, the SIR of the PVS in WM (Mean ± standard deviation, 1.83 ± 0.46) was significantly higher than that of the PVS in the BG (1.05 ± 0.154), CSFSyl (1.03 ± 0.15) and the CSFAC (0.97 ± 0.29). There was no significant difference between the SIR of the PVS in the BG compared to the CSFAC and CSFSyl. For the evaluation of the contrast enhancement effect, significant enhancement was observed in the PVS in the BG, the CSFAC and the CSFSyl compared to the pre-contrast scan. No significant contrast enhancement was observed in the PVS in WM. CONCLUSION: The signal intensity difference between the PVS in the BG versus WM on pre-contrast images suggests that the fluid composition might be different between these PVSs. The difference in the contrast enhancement between the PVSs in the BG versus WM suggests a difference in drainage function.

DOI： 10.2463/mrms.mp.2017-0137

Gadolinium-based Contrast Media, Cerebrospinal Fluid and the Glymphatic System: Possible Mechanisms for the Deposition of Gadolinium in the Brain. Reviewed

Toshiaki Taoka, Shinji Naganawa

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 17 ( 2 ) page： 111 - 119 2018

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

After Kanda's first report in 2014 on gadolinium (Gd) deposition in brain tissue, a considerable number of studies have investigated the explanation for the observation. Gd deposition in brain tissue after repeated administration of gadolinium-based contrast medium (GBCM) has been histologically proven, and chelate stability has been shown to affect the deposition. However, the mechanism for this deposition has not been fully elucidated. Recently, a hypothesis was introduced that involves the 'glymphatic system', which is a coined word that combines 'gl' for glia cell and 'lymphatic' system. According to this hypothesis, the perivascular space functions as a conduit for cerebrospinal fluid to flow into the brain parenchyma. The perivascular space around the arteries allows cerebrospinal fluid to enter the interstitial space of the brain tissue through water channels controlled by aquaporin 4. The cerebrospinal fluid entering the interstitial space clears waste proteins from the tissue. It then flows into the perivascular space around the vein and is discharged outside the brain. In addition to the hypothesis regarding the glymphatic system, some reports have described that after GBCM administration, some of the GBCM distributes through systemic blood circulation and remains in other compartments including the cerebrospinal fluid. It is thought that the GBCM distributed into the cerebrospinal fluid cavity via the glymphatic system may remain in brain tissue for a longer duration compared to the GBCM in systemic circulation. Glymphatic system may of course act as a clearance system for GBCM from brain tissue. Based on these findings, the mechanism for Gd deposition in the brain will be discussed in this review. The authors speculate that the glymphatic system may be the major contributory factor to the deposition and clearance of gadolinium in brain tissue.

DOI： 10.2463/mrms.rev.2017-0116

Single-stage Coil Embolization for Kissing Aneurysms of the Internal Carotid Artery Using Enterprise Stent: Three Cases Reports Reviewed

Takeshi Wada, Katsutoshi Takayama, Toshiaki Taoka, Kaoru Myouchin, Hiroyuki Nakagawa, Ichiro Nakagawa, Toshiteru Miyasaka, Shinichiro Kurokawa, Kimihiko Kichikawa

Journal of Neuroendovascular Therapy Vol. 12 ( 1 ) page： 6 - 13 2018

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Neuroendovascular Therapy

Purpose: Kissing aneurysms (KAs) are caused by the rare incidence of two aneurysms with different cervixes mutually contacting each other, with craniotomy surgical clipping having been reported as difficult. The objective was to investigate the treatment outcome of single-stage coil embolization using an Enterprise stent for internal carotid artery KA.Materials and Methods: The subjects consisted of three cases and six aneurysms (women: two cases, age: 42–70 years old, average: 55.7 years old) that underwent single-stage coil embolization using an Enterprise stent. Localization of the aneurysms was as follows: internal carotid artery-ophthalmic arterial bifurcation and internal carotid artery (C3): one case; internal carotid artery-posterior communicating arterial bifurcation and anterior choroidal arterial bifurcation: two cases; wherein, the maximum aneurysm diameter was 2.8–7.6 mm (average: 5.1 mm). The technical success rate, the presence of perioperative complications, the degree of embolus follow-up cerebral angiography after treatment (4–6 months, average: after 4.7 months), and more than 3 years follow-up contrast-enhanced magnetic resonance angiography (after 3.4–4.1 years, average: after 3.7 years) were assessed.Results: Coil embolization was successful in all cases, with no observation of perioperative complications. Upon follow-up angiography, complete occlusion (CO) was observed in all three cases and six aneurysms.Conclusion: The initial treatment outcome of single-stage coil embolization for carotid KA using an Enterprise stent was good.

DOI： 10.5797/jnet.oa.2017-0017

特集中枢神経系の新たな疾患カテゴリーとその画像所見 Glymphaticシステム　脳内の老廃物排除のための仕組み

田岡俊昭, 長縄慎二

臨床画像 Vol. 33 ( 12 ) page： 1447 - 1458 2017.12

Diffusion tensor tractography in the preoperative precise identification of the course of facial nerve in a meningioma of the cerebellopontine angle – Technical implications Reviewed International coauthorship

Gonçalo Neto d'Almeida, Luís Sousa Marques, Pedro Escada, Toshiaki Taoka, Pedro Gonçalves Pereira

Interdisciplinary Neurosurgery: Advanced Techniques and Case Management Vol. 9 page： 58 - 60 2017.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier B.V.

Background Facial paralysis remains as one of the major morbidities of surgery of cerebellopontine angle tumors. The preoperative standard Magnetic Resonance Image does not identify, with precision, the path of the facial nerve. Case description The authors describe a case of a 56 years-old female with a cerebellopontine angle meningioma, submitted to preoperative Diffusion Tensor Tractography to identification of the course of the facial nerve, and correlate its position with the intraoperative findings. There was an accurate correlation between the path of the facial nerve revealed by preoperative DTT and the route of the nerve identified during surgery. Conclusion The preoperative identification of the facial nerve seems to be possible by tractography in meningiomas of the cerebellopontine angle. It is possible that this technique may have utility in larger tumors, where the intraoperative identification of the facial path can be more difficult.

DOI： 10.1016/j.inat.2017.03.010

特集 MRI最前線ガドリニウム造影剤と脳脊髄液　glymphaticシステムとは何か?

田岡俊昭, 長縄慎二

臨床画像 Vol. 33 ( 6 ) page： 652 - 663 2017.6

Efficacy and safety of non-suture dural closure using a novel dural substitute consisting of polyglycolic acid felt and fibrin glue to prevent cerebrospinal fluid leakage-A non-controlled, open-label, multicenterclinical trial- Reviewed International journal

Shunsuke Terasaka, Toshiaki Taoka, Satoshi Kuroda, Nobutaka Mikuni, Toru Nishi, Hiroyuki Nakase, Yukihiko Fujii, Yasuhiko Hayashi, Jun-ichi Murata, Ken-ichiro Kikuta, Toshihiko Kuroiwa, Sachie Shimokawa, Kiyohiro Houkin

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE Vol. 28 ( 5 ) page： 69 - 69 2017.5

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The objective of this study is to evaluate the efficacy and safety of non-suture dural closure using a novel dural substitute (GM111) consisting of polyglycolic acid felt with a fibrin-glue-coated area commensurate in size with the dural defect. This was a non-controlled, open-label, multicenter clinical trial. The efficacy evaluation endpoints were (1) GM111's intra-operative capability to close dural defects and (2) prevention of cerebrospinal fluid (CSF) leakage and subcutaneous CSF retention throughout the postoperative period (evaluated by diagnostic imaging). Patients meeting the following three preoperative and two intra-operative selection criteria were enrolled: (1) between 12 and <75 years of age; (2) the dura is surmised to be defective and in need of reconstruction; (3) informed written consent was obtained from the patient; (4) the surgical wound is class 1; and (5) the size of duraplasty is >= 0.2 cm(2) to <100 cm(2). Sixty patients were enrolled. The craniotomy site was supratentorial in 77.2%, infratentorial in 12.3% and sellar in 10.5%. The GM111 prosthesis size ranged from 0.24 to 42 cm(2). To evaluate the efficacy, intra-operative closure was confirmed by Valsalva's maneuver, water infusion, etc., in all patients. CSF leakage and subcutaneous CSF retention throughout the postoperative period were found in four patients. Adverse events for which a causal relationship with GM111 could not be ruled out occurred in 8.8% of the patients. There were no instances of postoperative infection due to GM111. GM111 showed good closure capability and safety when used for non-suture dural closure.

DOI： 10.1007/s10856-017-5877-8

Carotid Artery Stenting Investigation of Plaque Protrusion Incidence and Prognosis Reviewed International journal

Masashi Kotsugi, Katsutoshi Takayama, Kaoru Myouchin, Takeshi Wada, Ichiro Nakagawa, Hiroyuki Nakagawa, Toshiaki Taoka, Shinichiro Kurokawa, Hiroyuki Nakase, Kimihiko Kichikawa

JACC-CARDIOVASCULAR INTERVENTIONS Vol. 10 ( 8 ) page： 824 - 831 2017.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

OBJECTIVES This study sought to clarify the incidence and prognosis of PP in carotid artery stenting (CAS).
BACKGROUND Projections thought to be plaque may be observed inside the stent on angiography or intravascular ultrasound (IVUS) during CAS. Known as plaque protrusion (PP), the incidence and prognosis of this complication are unclear.
METHODS A total of 354 consecutive carotid atherosclerotic stenoses in 328 patients (285 men, 43 women; age range 51 to 97 years [mean age 73.6 years]; 158 symptomatic cases; stenosis rate, 50% to 99% [mean 81.0%]) who underwent CAS under IVUS between October 2007 and March 2016 were retrospectively analyzed. PP was defined as plaque seen inside the stent lumen on both digital subtraction angiography and IVUS. The incidence and prognosis (rate of stroke within 30 post-operative days) of PP and the rate of ischemic lesions on the treated side on diffusion-weighted imaging performed within 48 post-operative hours within the PP group were investigated.
RESULTS PP was observed in 9 cases (2.6%). Ischemic stroke occurred in 6 of 9 PP cases (66.7%; 1 major, 5 minor). Ischemic lesions were observed on diffusion-weighted imaging in 8 of 9 cases (88.9%). PP was strongly associated with perioperative ischemic stroke. A significant increase in PP susceptibility was observed with open-cell stent use and unstable plaque.
CONCLUSIONS The incidence of PP in CAS was 2.6%, with a high risk of ischemic complications if PP was observed. The present findings indicate the necessity of appropriate device selection to avoid PP. (C) 2017 by the American College of Cardiology Foundation.

DOI： 10.1016/j.jcin.2017.01.029

すとらびすむす青い瞬間,魔法の時間

田岡俊昭

画像診断 Vol. 37 ( 3 ) page： 247 - 247 2017.2

Structure of the Medullary Veins of the Cerebral Hemisphere and Related Disorders Reviewed International journal

Toshiaki Taoka, Akio Fukusumi, Toshiteru Miyasaka, Hisashi Kawai, Toshiki Nakane, Kimihiko Kichikawa, Shinji Naganawa

RADIOGRAPHICS Vol. 37 ( 1 ) page： 280 - 296 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：RADIOLOGICAL SOC NORTH AMERICA

Deep medullary veins drain into subependymal veins with four convergence zones and show parallel distribution patterns adjacent to the body or inferior horn and a radial pattern in the frontal horn or trigon of the lateral ventricle. As white matter imaging develops such as diffusion tensor imaging or susceptibility-weighted imaging, requirements for understanding of white matter structures are increasing, not only for understanding of neuronal tracts but also for that of other structures including the fine anatomy of white matter vessels. Some disorders are related to deep medullary veins and show characteristic distributions of the lesions indicating the relationship to the medullary veins. When lesions show a parallel or radial distribution pattern in the certebral deep white matter, disorders related to deep medullary veins should be considered for differential diagnosis. In this review, we discuss disorders related to deep medullary veins, including (a) anomalies of the medullary veins, (b) hemorrhagic disorders related to the medullary veins (diffuse vascular injury due to high-energy trauma, deep medullary vein engorgement/thrombosis in neonates), (c) inflammatory changes that spread along the medullary veins, (d) neoplasms within the medullary veins, and (e) metabolic changes that lead to altered visualization of medullary veins. Understanding the anatomic structure of medullary veins in the cerebral hemisphere and becoming familiar with disorders in which the medullary veins play a major role in disease development may be helpful in the interpretation of brain images. (C) RSNA, 2017

DOI： 10.1148/rg.2017160061

Revisiting Current Golden Rules in Managing Acute Ischemic Stroke: Evaluation of New Strategies to Further Improve Treatment Selection and Outcome Reviewed

William T. C. Yuh, Matthew David Alexander, Toshihiro Ueda, Masayuki Maeda, Toshiaki Taoka, Kei Yamada, Norman J. Beauchamp

AMERICAN JOURNAL OF ROENTGENOLOGY Vol. 208 ( 1 ) page： 32 - 41 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ROENTGEN RAY SOC

OBJECTIVE. Advanced stroke imaging has generated much excitement for the early diagnosis of acute ischemic stroke (AIS) and facilitation of intervention. However, its therapeutic impact has not matched its diagnostic utility; most notably, lacking significant contributions to recent major AIS clinical trials. It is time to reexamine the fundamental hypotheses from the enormous body of imaging research on which clinical practices are based and reassess the current standard clinical and imaging strategies, or golden rules, established over decades for AIS. In this article, we will investigate a possible new window of opportunity in managing AIS through a better understanding of the following: first, the potential limitations of the golden rules; second, the significance of imaging-based parenchymal hypoperfusion (i.e., lower-thannormal relative cerebral blood flow [rCBF] may not be indicative of ischemia); third, the other critical factors (e.g., rCBF, collateral circulation, variable therapeutic window, chronicity of occlusion) that reflect more individual ischemic injury for optimal treatment selection; and, fourth, the need for penumbra validation in successfully reperfused patients (not in untreated patients).
CONCLUSION. Individual variations in the therapeutic window, ischemic injury (rCBF), and chronicity of vascular lesion development have not been comprehensively incorporated in the standard algorithms used to manage AIS. The current established imaging parameters have not been consistently validated with successfully reperfused patients and rCBF to quantitatively distinguish between oligemia and ischemia and between penumbra and infarct core within ischemic tissue. A novel paradigm incorporating rCBF values or indirectly incorporating relative rCBF values with higher statistically powered imaging studies to more reliably assess the severity of ischemic injury and differentiate reversibility from viability within the area of imaging-based parenchymal hypoperfusion may provide a more personalized approach to treatment, including no treatment of infarction core, to further enhance outcomes.

DOI： 10.2214/AJR.16.16557

Visualization of Middle Ear Ossicles in Elder Subjects with Ultra-short Echo Time MR Imaging Reviewed

Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka, Kojiro Suzuki, Shingo Iwano, Hiroko Satake, David Grodzki

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 16 ( 2 ) page： 93 - 97 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE MEDICINE

Purpose: To evaluate the visualization of middle ear ossicles by ultra-short echo time magnetic resonance (MR) imaging at 3T in subjects over 50 years old.
Materials and Methods: Sixty ears from 30 elder patients that underwent surgical or interventional treatment for neurovascular diseases were included (ages: 50-82, median age: 65; 10 men, 20 women). Patients received follow-up MR imaging including routine T1-and T2-weighted images, time-of-flight MR angiography, and ultra-short echo time imaging (PETRA, pointwise encoding time reduction with radial acquisition). All patients underwent computed tomography (CT) angiography before treatment. Thin-section source CT images were correlated with PETRA images. Scan parameters for PETRA were: TR 3.13, TE 0.07, flip angle 6 degrees, 0.83 x 0.83 x 0.83 mm resolution, 3 min 43 s scan time. Two radiologists retrospectively evaluated the visibility of each ossicular structure as positive or negative using PETRA images. The structures evaluated included the head of the malleus, manubrium of the malleus, body of the incus, long process of the incus, and the stapes. Signal intensity of the ossicles was classified as: between labyrinthine fluid and air, similar to labyrinthine fluid, between labyrinthine fluid and cerebellar parenchyma, or higher than cerebellar parenchyma.
Results: In all ears, the body of the incus was visible. The head of the malleus was visualized in 36/60 ears. The manubrium of the malleus and long process of the incus was visualized in 1/60 and 4/60 ears, respectively. The stapes were not visualized in any ear. Signal intensity of the visible structures was between labyrinthine fluid and air in all ears.
Conclusion: The body of the incus was consistently visualized with intensity between air and labyrinthine fluid on PETRA images in aged subjects. Poor visualization of the manubrium of the malleus, long process of the incus, and the stapes limits clinical significance of middle ear imaging with current PETRA methods.

DOI： 10.2463/mrms.mp.2015-0171

Gd-based Contrast Enhancement of the Perivascular Spaces in the Basal Ganglia Reviewed

Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 16 ( 1 ) page： 61 - 65 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE

Purpose: In textbooks, the perivascular space (PVS) is described as non-enhancing after the intravenous administration of gadolinium-based contrast agent (IV-GBCA). We noticed that the PVS sometimes has high signal intensity (SI) on heavily T-2-weighted 3D-FLAIR (hT(2)-FL) images obtained 4 h after IV-GBCA. The purpose of this study was to retrospectively evaluate the contrast enhancement of the PVS.
Materials and Methods: In 8 healthy subjects and 19 patients with suspected endolymphatic hydrops, magnetic resonance cisternography (MRC) and hT(2)-FL images were obtained before and 4 h after a single dose of IV-GBCA. No subjects had renal insufficiency. On axial MRC at the level of the anterior commissure (AC)-posterior commissure (PC) line, 1 cm circular regions of interest (ROIs) were drawn centering on the PVS in the bilateral basal ganglia and thalami. Three-millimeter diameter ROIs were set in the cerebrospinal fluid (CSF) of the bilateral ambient cistern. The ROIs on MRC were copied onto the hT2-FL images and the SI was measured. The SI ratio (SIR) was defined as SIRPVS = SI of PVS/SI of the thalami, and SIRCSF = SI of CSF/SI of the thalami. The average of the bilateral values was used for the calculation. The SIRCSF, SIRPVS, and SI of the thalami were compared between before and 4 h after IV-GBCA.
Results: The SIR was increased significantly from 1.02 +/- 0.37 to 2.65 +/- 0.82 in the CSF (P < 0.01) and from 1.20 +/- 0.35 to 2.13 +/- 1.23 in the PVS at 4 h after IV-GBCA (P < 0.01). The SI of the thalami showed no significant difference.
Conclusion: The enhancement of the PVS at 4 h after IV-GBCA was confirmed even in subjects without renal insufficiency. It is possible that the GBCA in the blood vessels might have permeated into the cerebrospinal fluid (CSF) space and the PVS. This might be a first step in the imaging evaluation of the glymphatic system (waste clearance system) of the brain.

DOI： 10.2463/mrms.mp.2016-0039

Lack of Contrast Enhancement in a Giant Perivascular Space of the Basal Ganglion on Delayed FLAIR Images: Implications for the Glymphatic System. Reviewed

Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 16 ( 2 ) page： 89 - 90 2017

Improved HYDROPS: Imaging of Endolymphatic Hydrops after Intravenous Administration of Gadolinium. Reviewed

Shinji Naganawa, Hisashi Kawai, Toshiaki Taoka, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 16 ( 4 ) page： 357 - 361 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

To improve the imaging protocol for the evaluation of endolymphatic hydrops after intravenous administration of a gadolinium-based contrast agent, we modified our previously reported hybrid of reversed image of positive endolymph signal and native image of positive perilymph signal (HYDROPS) method. Although the scan time of the new protocol was half that of the previous one, there were no significant differences between two protocols in the mean contrast noise ratio between the endolymph and perilymph and the area ratio of the endolymph size values in nine patients.

DOI： 10.2463/mrms.tn.2016-0126

Structures Showing Negative Correlations of Signal Intensity with Postnatal Age on T-1-weighted Imaging of the Brain of Newborns and Infants Reviewed

Saeka Hori, Toshiaki Taoka, Tomoko Ochi, Toshiteru Miyasaka, Masahiko Sakamoto, Katsutoshi Takayama, Takeshi Wada, Kaoru Myochin, Yukihiro Takahashi, Kimihiko Kichikawa

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 16 ( 4 ) page： 333 - 339 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE MEDICINE

Purpose: Although the neonatal and infantile brain typically shows sequential T-1 shortening according to gestational age as a result of myelination, several structures do not follow this rule. We evaluated the relationship between the signal intensity of various structures in the neonatal and infantile brain on T-1-weighted imaging (T1WI) and either postnatal or gestational age.
Materials and Methods: We examined magnetic resonance images from 120 newborns and infants without any abnormalities in the central nervous system. Written informed consent was obtained from all parents and the institutional review board approved the study. Gestational age at examination ranged from 35 weeks, 3 days to 46 weeks, 6 days, and postnatal age ranged from 7 days to 127 days. Signal intensity on T1WI was evaluated on a scale from Grade 1 (indistinguishable from surrounding structures) to Grade 4 (higher than cortex and close to fat). We evaluated relationships between the T-1 signal grades of various structures in the neonatal brain and postnatal or gestational age using Spearman's correlation analysis.
Results: Significant positive correlations were identified between T-1 signal grade and gestational age in the pyramidal tract (P < 0.001). Conversely, significant negative correlations were evident between T-1 signal grade and postnatal age (P < 0.001), in structures including the stria medullaris thalami, fornix cerebellar vermis, dentate nucleus and anterior pituitary gland.
Conclusion: Significant negative correlations exist between signal intensity on T1WI and postnatal age in some structures of the neonatal and infantile brain. Some mechanisms other than myelination might play roles in the course of signal appearance.

DOI： 10.2463/mrms.mp.2015-0168

Diffusion Tensor Imaging in Dementia Reviewed

Taoka Toshiaki

Neuroimaging Diagnosis for Alzheimer's Disease and Other Dementias page： 117 - 128 2017

特集脳腫瘍WHO2016　−読影のための実践講座− 転移性脳腫瘍

田岡俊昭

画像診断 Vol. 36 ( 13 ) page： 1303 - 1313 2016.10

Application of histogram analysis for the evaluation of vascular permeability in glioma by the K2 parameter obtained with the dynamic susceptibility contrast method: Comparisons with Ktrans obtained with the dynamic contrast enhance method and cerebral blood volume Reviewed International journal

Toshiaki Taoka, Hisashi Kawai, Toshiki Nakane, Saeka Hori, Tomoko Ochi, Toshiteru Miyasaka, Masahiko Sakamoto, Kimihiko Kichikawa, Shinji Naganawa

MAGNETIC RESONANCE IMAGING Vol. 34 ( 7 ) page： 896 - 901 2016.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Purpose: The "K2" value is a factor that represents the vascular permeability of tumors and can be calculated from datasets obtained with the dynamic susceptibility contrast (DSC) method. The purpose of the current study was to correlate K2 with Ktrans, which is a well-established permeability parameter obtained with the dynamic contrast enhance (DCE) method, and determine the usefulness of K2 for glioma grading with histogram analysis.
Methods: The subjects were 22 glioma patients (Grade II: 5, III: 6, IV: 11) who underwent DSC studies, including eight patients in which both DSC and DCE studies were performed on separate days within 10 days. We performed histogram analysis of regions of interest of the tumors and acquired 20th percentile values for leakage-corrected cerebral blood volume (rCBV(20%ile)), K2 (K2(20%ile)), and for patients who underwent a DCE study, Ktrans (Ktrans(20%ile)).We evaluated the correlation between K2(20%ile) and Ktrans(20%ile) and the statistical difference between rCBV(20%ile) and K2(20%ile).
Results: We found a statistically significant correlation between K2(20%ile) and Ktrans(20%ile) (r = 0.717, p < 0.05). rCBV(20%ile) showed a significant difference between Grades II and III and between Grades II and IV, whereas K2(20%ile) showed a statistically significant (p < 0.05) difference between Grades II and IV and between Grades III and IV.
Conclusions: The K2 value calculated from the DSC dataset, which can be obtained with a short acquisition time, showed a correlation with Ktrans obtained with the DCE method and may be useful for glioma grading when analyzed with histogram analysis. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.mri.2016.04.020

Advantages of Diffusion Tensor Tractography of Facial Nerve in Vestibular Schwannomas Surgeries: A Multicenter Study Reviewed International coauthorship

Gon{\c{c } }alo Almeida, Pedro Pereira, Luis Marques, Pedro Escada, Kimihiko Kichikawa, Shinji Naganawa, Toshiaki Taoka

Journal of Neurological Surgery Part B: Skull Base Vol. 77 ( S 02 ) 2016.9

Diffusion tensor studies and voxel-based morphometry of the temporal lobe to determine the cognitive prognosis in cases of Alzheimer's disease and mild cognitive impairment: Do white matter changes precede gray matter changes? Reviewed International journal

Toshiaki Taoka, Fumihiko Yasuno, Masayuki Morikawa, Makoto Inoue, Kuniaki Kiuchi, Soichiro Kitamura, Kiwamu Matsuoka, Toshifumi Kishimoto, Kimihiko Kichikawa, Shinji Naganawa

SPRINGERPLUS Vol. 5 ( 1 ) page： 1023 - 1023 2016.7

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER INTERNATIONAL PUBLISHING AG

Purpose: The purpose of the current study was to assess the feasibility of diffusion tensor imaging (DTI) parameters for determining the prognosis of Alzheimer's disease (AD). We also analyzed the correlation among DTI, voxel-based morphometry (VBM), and results of the mini-mental state examination (MMSE).
Methods: The subjects of this prospective study were patients with AD and mild cognitive impairment. We performed annual follow-ups with DTI, VBM, and MMSE for 2 or 3 years. On DTI, the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the uncinate fascicles were measured. VBM was performed to provide a z-score for the parahippocampal gyrus. The correlations among these factors were evaluated in the same period and the next period of the follow-up study.
Results: For evaluation of the same period, both DTI parameters and z-scores showed statistically significant correlations with the MMSE score. Also for evaluation of the next period, both DTI parameters and z-scores showed statistically significant correlations with the MMSE score of the next period. We observed a statistically significant correlation between the ADC value of the uncinate fascicles and the z-score of the next period.
Conclusions: Diffusion tensor parameters (ADC and FA) of the uncinate fascicles correlated well with cognitive function in the next year and seemed to be feasible for use as biomarkers for predicting the progression of AD. In addition, the white matter changes observed in the ADC seemed to precede changes in the gray matter volume of the parahippocampal gyrus that were represented by z-scores of VBM.

DOI： 10.1186/s40064-016-2692-5

Dural Thickening of the Internal Auditory Canal in Patients With Spontaneous Intracranial Hypotension Syndrome Reviewed International journal

Saeka Hori, Toshiaki Taoka, Toshiteru Miyasaka, Tomoko Ochi, Masahiko Sakamoto, Takeshi Wada, Kaoru Myochin, Katsutoshi Takayama, Kimihiko Kichikawa

JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Vol. 40 ( 2 ) page： 297 - 300 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Objective This study aimed to assess the utility of dural thickening of the internal auditory canal (IAC) in patients with spontaneous intracranial hypotension (SIH) syndrome and determined the sensitivity and specificity of this image finding.
Methods Magnetic resonance images were evaluated for 22 cases of definite SIH and 16 cases of unlikely SIH. On contrast-enhanced magnetic resonance imaging, pachymeningeal enhancement and dural thickening of the IAC were assessed.
Results Pachymeningeal enhancement was observed in 21 of 22 patients in the definite SIH group and 1 of 16 patients in the unlikely SIH group (sensitivity, 95.5%; specificity, 93.8%). Dural thickening of the IAC was observed in 15 of 22 patients in the definite SIH group and 0 of 16 patients in the unlikely SIH group (sensitivity, 68.2%; specificity, 100%).
Conclusions Dural thickening of the IAC showed 100% specificity for SIH syndrome and can increase the accuracy of diagnosis of SIH syndrome.

DOI： 10.1097/RCT.0000000000000342

Time Course of Diffusion Kurtosis in Cerebral Infarctions of Transient Middle Cerebral Artery Occlusion Rat Model Reviewed International journal

Toshiaki Taoka, Masayuki Fujioka, Yuto Kashiwagi, Atsushi Obata, Takemi Rokugawa, Masaaki Hori, Yoshitaka Masutani, Shigeki Aoki, Shinji Naganawa, Kohji Abe

JOURNAL OF STROKE & CEREBROVASCULAR DISEASES Vol. 25 ( 3 ) page： 610 - 617 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Objective: To evaluate the relationship between fiber bundle direction and changes in diffusion kurtosis, we evaluated the apparent diffusion kurtosis coefficients (AKCs) that were perpendicular to and parallel to the principal diffusion tensor eigenvector. Materials and Methods: Adult male Wistar rats were subjected to 30 or 60 minutes of middle cerebral artery occlusion and imaged with a 7T Magnetic Resonance Imager System (Varian MRI System 7T/210: Agilent Technologies, CA). Diffusion kurtosis images were obtained before middle cerebral artery (MCA) reperfusion and 3, 6, and 24 hours after reperfusion to generate the apparent diffusion coefficient (ADC), fractional anisotropy (FA), mean apparent diffusion kurtosis coefficient (mAKC), AKC axial to the eigenvector (axAKC), and AKC radial to the eigenvector (radAKC) images. The time course of the region/normal ratio was evaluated for the above parameters in the caudoputamen and white matter. Results: Relative FA and relative ADC values decreased 3 hours after MCA reperfusion and remained decreased until 24 hours. Relative mAKC, axAKC, and radAKC values were increased 3 hours after MCA reperfusion, peaked after 6 hours, and slightly decreased after 24 hours. In the white matter, axAKC showed larger changes than radAKC. Conclusion: The time course of the diffusion kurtosis value showed earlier pseudonormalization than the ADC value of the lesions. For white matter lesions, the increase in axAKC was larger than that in radAKC, suggesting that the tissue changes after infarction mainly produce reduced diffusivity along the fibers and lead to increased inhomogeneity of the diffusion.

DOI： 10.1016/j.jstrokecerebrovasdis.2015.11.028

Heavily T-2-Weighted 3D-FLAIR Improves the Detection of Cochlear Lymph Fluid Signal Abnormalities in Patients with Sudden Sensorineural Hearing Loss Reviewed

Shinji Naganawa, Hisashi Kawai, Toshiaki Taoka, Kojiro Suzuki, Shingo Iwano, Hiroko Satake, Michihiko Sone, Mitsuru Ikeda

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 15 ( 2 ) page： 203 - 211 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE

Purpose: To compare the signal increase in cochlear lymph fluid on three-dimensional fluid attenuated inversion recovery (3D-FLAIR) in patients with sudden sensorineural hearing loss (SNHL) between regular contrast 3D-FLAIR (FL) and heavily T-2-weighted 3D-FLAIR (HF).
Methods: Twenty-five patients with unilateral sudden SNHL and eight healthy volunteers were included. Patients were divided into two groups: the mild group consisted of 9 patients, with an average hearing level of 60 dB or less; the severe group consisted of 16 patients, with an average hearing level of more than 60 dB. All patients and healthy volunteers underwent magnetic resonance (MR) cisternography for anatomical reference of the fluid space with FL and HF at 3 T. The region of interest (ROI) was manually drawn on the mid-modiolar section of the MR cistemography around the cochlea. The ROI for noise was drawn within the air space. ROIs were copied onto the FL and HF images. The contrast-to-noise ratio (CNR) between the affected and non-affected ear was measured in the patient group and the CNR between the right and left ear was also measured in the control group. Differences in the CNR on FL and HF images among the three groups were tested by one-way analysis of variance (ANOVA).
Results: There was a statistically significant difference in mean CNR on HF among the three groups (P < 0.001). Furtheimore, based on pairwise comparisons, there was a statistically significant difference between them in mean CNR on HF (P < 0.05). There was no statistically significant difference in mean CNR on FL among the three groups (P = 0.074).
Conclusions: HF is more sensitive to signal alterations in cochleae with sudden SNHL than FL.

DOI： 10.2463/mrms.mp.2015-0065

Cochlear Lymph Fluid Signal Increase in Patients with Otosclerosis after Intravenous Administration of Gadodiamide Reviewed

Shinji Naganawa, Hisashi Kawai, Toshiaki Taoka, Kojiro Suzuki, Shingo Iwano, Hiroko Satake, Michihiko Sone, Mitsuru Ikeda

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 15 ( 3 ) page： 308 - 315 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE

Purpose: Increased cochlear lymph fluid signals on three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) images obtained several minutes after intravenous administration of a single dose of gadolinium-based contrast agent (IV-SD-GBCA) in a patient with severe retro-fenestral type otosclerosis had been reported. This increase was thought to represent breakdown of the blood-labyrinthine barrier. The purpose of this study was to evaluate cochlear lymph signal on heavily T-2-weighted 3D-FLAIR (HF) images obtained 4 hours after IV-SD-GBCA in patients with otosclerosis, Meniere's disease, and healthy subjects.
Materials and Methods: Twenty-two ears from 12 patients with otosclerotic plaques determined by computed tomography (CT), 16 ears from 8 healthy volunteers, and 10 ears from 9 Meniere's disease patients with significant endolymphatic hydrops on magnetic resonance (MR) images were retrospectively analyzed. Images were obtained 4 hours after IV-SD-GBCA. Patients and healthy volunteers underwent MR cisternography (MRC) for anatomical reference of the fluid space and HF at 3T. The region of interest (ROI) was manually drawn on MRC images around the scala tympani in the basal cochlear turn. The reference ROI was set in the cerebellum. ROIs were copied onto HF images and the signal intensity ratio (SIR) of cochlear perilymph to cerebellum was measured. Differences in the SIR on HF images among the three groups were tested by one-way analysis of variance (ANOVA).
Results: The mean SIR was 24.0 +/- 10.1 in otosclerosis patients, 7.9 +/- 1.5 in volunteers, and 11.6 +/- 3.9 in Meniere's disease patients. The mean SIR was significantly higher in the otosclerosis group than in the other groups (P < 0.001). In the otosclerosis group, there was a significant difference in the SIR between the retrofenestral type and the fenestral type (P = 0.033).
Conclusions: In patients with otosclerosis, the SIR was higher than in Meniere's disease patients or in healthy volunteers. The SIR was higher in the retrofenestral type than in the fenestral type.

DOI： 10.2463/mrms.mp.2015-0121

Progress in magnetic resonance diffusion image Reviewed

Toshiaki Taoka

Japanese Journal of Neurosurgery Vol. 25 ( 5 ) page： 402 - 410 2016

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Congress of Neurological Surgeons

Diffusion of water is based on the principle that water molecules show random motion. In diffusion studies on magnetic resonance imaging using a motion proving gradient, a signal decrease which is caused by molecular diffusion in the tissue provides information about tissue structure and physiological status. Diffusion-weighted images play a very important role in brain related diagnosis, especially for acute infarctions, and have become an essential tool in clinical practice. Diffusion tensor imaging using the Gaussian distribution model also has made strides in evaluating anisotropic water diffusion in the white matter in which water diffusion is restricted by macromolecules, membrane, and myelin. Diffusion tensor imaging is based on a mathematical model of an ellipsoid. Thus principal directions of diffusion and the magnitude of diffusion along those directions can be calculated. Diffusion tensor tractography is an innovative application of the diffusion tensor method which can access the pathways of neuronal fibers. However, neuronal tissue is a highly heterogeneous structure on various scales and the Gaussian distribution has only been adapted for free diffusion in a fluid that is uniform and sufficiently large. Complicated wall structures exist in the neuronal tissue, and the Gaussian distribution model does not reflect the existence of a large number of compartments and nerve tracts, particularly in the central nervous system. Therefore, instead of a simple Gaussian distribution model, measurement of the probability distribution of a detailed water molecule is necessary. One method is q-space imaging (QSI). QSI is performed by measuring a large amount of diffusion encoding and can provide the probability density function of individual water molecules. Although QSI is theoretically superior to conventional Gaussian distribution analysis, one limitation of QSI is the long acquisition time due to the large sampling number. The concept of kurtosis is another method to evaluate non-Gaussianity. Kurtosis is a quantity that reflects a gap between the diffusion distribution of a water molecule in vivo and the Gaussian distribution, and can be calculated from datasets of relatively few diffusion encoding elements compared to QSI. Thus, a rather short acquisition time is required for kurtosis. Recently, other innovative applications of non-Gaussian diffusion have been introduced including neurite orientation dispersion and density imaging (NODDI) which is a model-based diffusion technique that allows for the quantification of specific microstructural features directly related to neuronal morphology. These novel techniques will provide useful information on tissue microstructure not only in the scientific research but also in the clinical practice.

DOI： 10.7887/jcns.25.402

Enterprise Stent-assisted Cerebral Aneurysm Coiling: Can Antiplatelet Therapy be Terminated after Neointima Formation with the Enterprise Stent? Reviewed

Katsutoshi Takayama, Toshiaki Taoka, Kaoru Myouchin, Takeshi Wada, Hiroyuki Nakagawa, Ichiro Nakagawa, Toshiteru Miyasaka, Masahiko Sakamoto, Shinichiro Kurokawa, Kimihiko Kichikawa

Journal of Neuroendovascular Therapy Vol. 10 ( 4 ) page： 201 - 205 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Neuroendovascular Therapy

Objective: Patients who undergo Enterprise stent (ES)-assisted cerebral aneurysm coiling require long-term antiplatelet therapy (AT). Some studies have reported that cessation or modification of AT increases the risk of cerebral infarction. The aim of this study was to evaluate whether AT can terminated without increasing the risk of ischemic events among patients who have undergone ES-assisted cerebral aneurysm coiling.Methods: This study evaluated 9 with 11 unruptured aneurysms were confirmed to have neointima formation with the ES on follow-up angiography. Dual AT was given for ≥3 months postoperatively, then one antiplatelet agent was administered until ≥6 months postoperatively before termination of all AT. Incidences of ipsilateral ischemic events and stent occlusion after AT termination were assessed prospectively.Results: During follow-up (mean, 32.8 months; range, 21.5–51.3 months) ipsilateral ischemic events and stent occlusion did not occur in any cases.Conclusion: Termination of AT ≥6 months postoperatively did not result in ischemic events among patients with neointima formation after ES-assisted cerebral aneurysm coiling.

DOI： 10.5797/jnet.oa.2016-0052

Time Course of Diffusion Kurtosis in Cerebral Infarctions of Transient Middle Cerebral Artery Occlusion Rat Model Reviewed

Taoka T, Fujioka M, Kashiwagi Y, Obata A, Rokugawa T, Hori M, Masutani Y, Aoki S, Naganawa S, Abe K.

J Stroke Cerebrovasc Dis. 2015.12

進行性核上性麻痺における小脳歯状核のMRI信号変化

澤信宏, 形岡博史, 桐山敬生, 泉哲石, 田岡俊昭, 吉川公彦, 上野聡

臨床神経学 Vol. 55 ( Suppl. ) page： S427 - S427 2015.12

A case of meningococcal meningitis with multiple cerebellar microbleeds detected by susceptibility-weighted imaging Reviewed International journal

Keita Miyazaki, Hidetada Fukushima, Youhei Kogeichi, Tomoo Watanabe, Kazunobu Norimoto, Toshiaki Taoka, Kazuo Okuchi

BMC MEDICAL IMAGING Vol. 15 ( 1 ) page： 45 - 45 2015.10

Language：English Publishing type：Research paper (scientific journal) Publisher：BIOMED CENTRAL LTD

Background: Bacterial meningitis is a fatal infectious disease of the central nervous system complicating intravascular involvements. Multiple microbleeds are rarely identified as complications because of the limited detection threshold of conventional imaging modalities. We report the first case of meningococcal meningitis with successful identification of multiple microbleeds in the cerebellum by susceptibility-weighted imaging.
Case presentation: A 19-year-old Japanese female was brought to our emergency department because of fever and coma. A spinal tap was performed and turbid yellow fluid was collected. A diagnosis of bacterial meningitis was established and the patient was admitted to an intensive care unit. Dexamethasone and Antibiotics were administered and Neisseria meningitides was cultured from the spinal fluid. On day 10, postcontrast magnetic resonance imaging identified enhanced subarachnoid space in the cerebellum. Susceptibility-weighted imaging showed spotty low-intensity signals in the cerebellar tissue, indicating microbleeds. The patient made a full recovery from coma and was discharged without neurological sequelae on day 24.
Conclusion: Meningococcal meningitis can cause multiple microbleeds in the cerebellum. In this report, we successfully identified microbleeds by susceptibility-weighed imaging. Using this imaging modality, further investigations will clarify its clinical incidence and significance.

DOI： 10.1186/s12880-015-0090-z

Characteristic Mill findings of upper limb muscle involvement in myotonic dystrophy type 1 Reviewed

K. Sugie, M. Sugie, T. Taoka, Y. Tonomura, A. Kumazawa, T. Izumi, S. Ueno, K. Kichikawa

NEUROMUSCULAR DISORDERS Vol. 25 page： S272 - S272 2015.10

Utility of High-b-Value Diffusion-Weighted Magnetic Resonance Imaging in Evaluating Reversible Medial Longitudinal Fasciculus Syndrome Caused by Acute Brainstem Ischemia Reviewed International journal

Yusuke Miki, Masayuki Fujioka, Toshiaki Taoka, Hiroaki Tanaka, Shiro Chitoku, Takeshi Matsuyama, Shigeko Tanaka

JOURNAL OF STROKE & CEREBROVASCULAR DISEASES Vol. 24 ( 6 ) page： E157 - E159 2015.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Background: Medial longitudinal fasciculus (MLF) syndrome refers to a gaze disorder characterized by impaired adduction on the ipsilateral side to the injured MLF, with dissociated nystagmus of the contralateral abducting eye. The most common cause of the MLF syndrome is ischemic stroke. However, acute ischemic change in the MLF may be undetectable even on diffusion-weighted magnetic resonance imaging (DW-MRI) partly because of its small size and specific brainstem location. Case Report: Herein, we present the first reported case of MLF syndrome in which, compared with the standard-b-value DWI, a higher b-value DWI revealed more clearly a small infarction in the dorsal pons in the acute stage. Conclusions: We suggest that high-b-value DWI can be a useful diagnostic method for patients with MLF syndrome caused by possible brainstem ischemia and thus supportive for deciding the optimal treatment for such patients.

DOI： 10.1016/j.jstrokecerebrovasdis.2015.03.002

"Cerebellar peduncle quarter notes" formed by the superior and middle cerebellar peduncles: comparison with a diffusion tensor study of spinocerebellar degeneration Reviewed

Characteristic MRI Findings of upper Limb Muscle Involvement in Myotonic Dystrophy Type 1 Reviewed

Sugie K, Sugie M, Taoka T, Tonomura Y, Kumazawa A, Izumi T, Kichikawa K, Ueno S.

PLoS One. Vol. 10 ( 4 ) page： e0125051 2015.4

Tomoko Ochi, Toshiaki Taoka, Toshiteru Miyasaka, Takeshi Wada, Masahiko Sakamoto, Saeka Hori, Kimihiko Kichikawa

JAPANESE JOURNAL OF RADIOLOGY Vol. 33 ( 4 ) page： 210 - 215 2015.4

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

To investigate morphological changes of the superior and middle cerebellar peduncles (SCP, MCP) in spinocerebellar degeneration (SCD) by observing "cerebellar peduncle quarter notes".
We examined 21 patients with SCD, including nine patients with multiple system atrophy cerebellar type (MSA-C), and 24 controls. We measured SCP angle and performed diffusion tensor analysis to quantify the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the MCP. We quantified the relationship between SCP angle and the ADC and FA of the MCP, and compared these variables between MSA-C patients and controls.
There was statistically significant negative correlation between SCP angle and FA of the MCP, and a positive correlation between SCP angle and the ADC of the MCP. Mean SCP angle was larger among MSA-C patients than among normal controls.
SCP angle tended to be larger among patients with severe degeneration of the MCP. The SCP angle, quantified by observing "cerebellar peduncle quarter notes", may be a simple index for evaluation of degeneration of the MCP.

DOI： 10.1007/s11604-015-0409-2

Comparison between angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on the risk of stroke recurrence and longitudinal progression of white matter lesions and silent brain infarcts on MRI (CEREBRAL study): rationale, design, and methodology Reviewed

Shigeru Yamano, Manabu Horii, Takeshi Takami, Mio Sakuma, Takeshi Morimoto, Sadanori Okada, Toshiaki Taoka, Kimihiko Kichikawa, Hiroyuki Sasamura, Hiroshi Itoh, Yoshiko Furuya, Satoshi Ueno, Tomoaki Imamura, Seigo Sugiyama, Hisao Ogawa, Yoshihiko Saito

INTERNATIONAL JOURNAL OF STROKE Vol. 10 ( 3 ) page： 452 - 456 2015.4

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

ObjectivesPatients with a history of ischemic stroke are known to develop new ischemic stroke. While asymptomatic, the presence and progression of silent brain infarcts and white matter lesions on magnetic resonance imaging are associated with an increased risk of future strokes. Both angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are recommended for the primary and secondary prevention of stroke, but there are no direct comparisons of angiotensin-converting enzyme inhibitors versus angiotensin II receptor blockers regarding their cerebroprotective effects, including their effect on asymptomatic cerebral lesions detected by magnetic resonance imaging.
MethodsElderly (65 years or older) patients with essential hypertension who underwent cerebral magnetic resonance imaging and were found to have any cerebral ischemic lesions, such as cerebral infarction, silent brain infarct, or white matter lesion, were enrolled in this CEREBRAL study. Patients who agreed to participate were enrolled in the randomized controlled trial portion. Patients who did not agree to participate in the randomized controlled trial were enrolled in the cohort study portion. After two-years of angiotensin-converting enzyme inhibitor or angiotensin II receptor blockers treatment, follow-up magnetic resonance imaging examination will be performed. The primary end-point is the composite of (1) occurrence of a fatal or nonfatal cerebrovascular event or (2) progression of cerebrovascular lesions as evaluated by magnetic resonance imaging, including white matter lesions or silent brain infarcts. After enrollment, cognitive function was evaluated, if possible, using the Mini-Mental State Examination.
ConclusionsOur study will clarify whether angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers are more effective for preventing primary and recurrence of ischemic stroke, including the progression of asymptomatic cerebral lesions on magnetic resonance imaging, in elderly hypertensive patients.

DOI： 10.1111/ijs.12085

特集解剖学的構造を念頭においた中枢神経疾患の画像診断脳梁の病変

宮坂俊輝, 田岡俊昭

画像診断 Vol. 35 ( 5 ) page： 517 - 527 2015.3

A Magnetic Resonance Imaging Technique to Evaluate Tumor-Brain Adhesion in Meningioma: Brain-Surface Motion Imaging Reviewed International journal

Shuichi Yamada, Toshiaki Taoka, Ichiro Nakagawa, Fumihiko Nishimura, Yasushi Motoyama, Young S. Park, Hiroyuki Nakase, Kimihiko Kichikawa

WORLD NEUROSURGERY Vol. 83 ( 1 ) page： 102 - 107 2015.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

OBJECTIVE: We examined the effectiveness of a newly developed magnetic resonance imaging (MRI) technique, brain surface motion imaging (BSMI), in the preoperative evaluation of tumor-brain adhesion in meningioma surgery.
METHODS: Cine phase-contrast MRI was used to measure cerebrospinal fluid (CSF) pulsations and heart rates at 2 different time points to create a subtraction image in meningioma patients who underwent BSMI. With no tumor-brain adhesion, a gap was observed in the tumor-brain movements, resulting in an outline of the tumor in BSMI. If adhesion was evident, no outline was observed. Cases were evaluated as exact if the presence or absence of edema in T2-weighted MRI, BSMI findings, and intraoperative findings all matched; as effected when only BSMI findings and intraoperative images matched; and as false when BSMI findings and intraoperative findings did not match.
RESULTS: BSMI judged 27 patients as adhesion (+) and 33 as adhesion (-), whereas surgical findings evaluated 22 as adhesion (+) and 38 as adhesion (-). The sensitivity and specificity were both high, at 95.5% and 84.2%, respectively. Forty-one of 60 patients were evaluated as exact, 12 as effected, and 7 as false. World Health Organization tumor grade assessment of effected subjects included 16.7% in grade 1 and 36.4% in grade 2.
CONCLUSIONS: BSMI was shown to be effective in evaluating adhesion between the meningioma and the brain, allowing safe and effective removal planning to be carried out preoperatively.

DOI： 10.1016/j.wneu.2013.02.015

Characteristic MRI Findings of upper Limb Muscle Involvement in Myotonic Dystrophy Type 1

Kazuma Sugie, Miho Sugie, Toshio Taoka, Yasuyo Tonomura, Aya Kumazawa, Tesseki Izumi, Kimihiko Kichikawa, Satoshi Ueno

PLOS ONE Vol. 10 ( 4 ) page： e0125051 2015

Language：English Publishing type：Research paper (scientific journal) Publisher：PUBLIC LIBRARY SCIENCE

The objective of our study was to evaluate the relation between muscle MRI findings and upper limb weakness with grip myotonia in patients with myotonic dystrophy type 1 (DM1). Seventeen patients with DM1 were evaluated by manual muscle strength testing and muscle MRI of the upper limbs. Many DM1 patients presenting with decreased grasping power frequently showed high intensity signals in the flexor digitorum profundus (FDP) muscles on T1-weighted imaging. Patients presenting with upper limb weakness frequently also showed high intensity signals in the flexor pollicis longus, abductor pollicis longus, and extensor pollicis muscles. Disturbances of the distal muscles of the upper limbs were predominant in all DM1 patients. Some DM1 patients with a prolonged disease duration showed involvement of not only distal muscles but also proximal muscles in the upper limbs. Muscle involvement of the upper limbs on MRI strongly correlated positively with the disease duration or the numbers of CTG repeats. To our knowledge, this is the first study to provide a detailed description of the distribution and severity of affected muscles of the upper limbs on MRI in patients with DM1. We conclude that muscle MRI findings are very useful for identifying affected muscles and predicting the risk of muscle weakness in the upper limbs of DM1 patients.

DOI： 10.1371/journal.pone.0125051

Enterprise stentを用いた脳動脈瘤コイル塞栓術後フォローアップ 3D time-of-flight magnetic resonance angiography(MRA)および造影MRAの診断能

和田敬, 高山勝年, 明珍薫, 宮坂俊輝, 田岡俊昭, 中川裕之, 吉川公彦, 黒川紳一郎, 中川一郎, 中瀬裕之

JNET: Journal of Neuroendovascular Therapy Vol. 8 ( 6 ) page： 265 - 265 2014.12

Time Course of Axial and Radial Diffusion Kurtosis of White Mafter Infarctions: Period of Pseudonormalization International coauthorship

T. Taoka, M. Fujioka, M. Sakamoto, T. Miyasaka, T. Akashi, T. Ochi, S. Hori, M. Uchikoshi, J. Xu, K. Kichikawa

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 35 ( 8 ) page： 1509 - 14 2014.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: Diffusion kurtosis is a statistical measure for quantifying the deviation of the water diffusion profile from a Gaussian distribution. The current study evaluated the time course of diffusion kurtosis in patients with cerebral infarctions, including perforator, white matter, cortical, and watershed infarctions.
MATERIALS AND METHODS: Subjects were 31 patients, representing 52 observations of lesions. The duration between the onset and imaging ranged from 3 hours to 122 days. Lesions were categorized into 4 groups listed above. Diffusion kurtosis images were acquired with b-values of 0, 1000, and 2000 s/mm(2) applied in 30 directions; variables including DWI signal, ADC, fractional anisotropy, radial diffusivity, axial diffusivity, radial kurtosis, and axial kurtosis, were obtained. The time courses of the relative values (lesion versus contralateral) for these variables were evaluated, and the pseudonormalization period was calculated.
RESULTS: Diffusion kurtosis was highest immediately after the onset of infarction. Trend curves showed that kurtosis decreased with time after onset. Pseudonormalization for radial/axial kurtosis occurred at 13.2/59.9 days for perforator infarctions, 33.1/40.6 days for white matter infarctions, 34.8/35.9 days for cortical infarctions, and 34.1/28.2 days after watershed infarctions. For perforator infarctions, pseudonormalization occurred in the following order: radial kurtosis, ADC, axial kurtosis, and DWI.
CONCLUSIONS: Diffusion kurtosis variables in lesions increased early after infarction and decreased with time. Information provided by diffusion kurtosis imaging, including axial and radial kurtosis, seems helpful in conducting a detailed evaluation of the age of infarction, in combination with T2WI, DWI, and ADC.

DOI： 10.3174/ajnr.A3908

Comparison of brain 3.0-T with 1.5-T MRI in patients with multiple sclerosis: A 6-month follow-up study

Hiroshi Kataoka, Takao Kiriyama, Toshiaki Taoka, Naoki Oba, Megumi Takewa, Nobuyuki Eura, Ryogo Syobatake, Yasuyo Kobayashi, Masahiro Kumazawa, Tesseki Izumi, Yoshiko Furiya, Nobufusa Aoyama, Kimihiko Kichikawa, Satoshi Ueno

CLINICAL NEUROLOGY AND NEUROSURGERY Vol. 121 page： 55 - 8 2014.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Objectives: The 2010 revisions to the McDonald criteria for the diagnosis of multiple sclerosis (MS) were recently published. One objective of the revision was to simplify the MRI criteria. The MRI criteria do not specify magnetic field strength. We studied whether there was any difference in diagnosis between brain 3.0-T and 1.5-T MRI according to the 2010 revisions of the McDonald criteria.
Patients and methods: We prospectively studied brain 3.0-T and 1.5-T MRI in 22 patients with MS. 1.5-T MRI was performed 24 h after 3.0-T MRI, and the scanning protocol included contiguous axial sections of T2-weighted images (T2WI), T1WI, and enhanced T1WI. These two different MRI and neurological assessments were scheduled to be repeated 3 and 6 months after study entry.
Results: The regions where MS lesions were better visualized on 3.0-T MRI tended to be in deep white matter on T2WI. Dissemination of lesions in space and time was similar for 3.0-T and 1.5-T MRI.
Conclusion: Our study found no difference between brain 3.0-T and 1.5-T MRI. There was no apparent impact of brain 3.0-T MRI on the diagnosis of MS according to the 2010 version of the MRI criteria. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.clineuro.2014.03.018

Long-term treatment outcomes after intravascular ultrasound evaluation and stent placement for atherosclerotic subclavian artery obstructive lesions

Takeshi Wada, Katsutoshi Takayama, Toshiaki Taoka, Hiroyuki Nakagawa, Kaoru Myouchin, Toshiteru Miyasaka, Toshiaki Akashi, Masahiko Sakamoto, Kimihiko Kichikawa

Neuroradiology Journal Vol. 27 ( 2 ) page： 213 - 21 2014.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Edizioni del Centauro

The objective of this study was to determine long-term outcomes after stent placement for subclavian artery (SA) obstructive lesions assisted by intraoperative intravascular ultrasound (IVUS). The study included 25 lesions in 24 patients who underwent stent placement assisted by intraoperative IVUS for subclavian artery stenosis or obstruction at our hospital between January 2003 and August 2010. Outcome was evaluated based on the results within 30 postoperative days (technical success rate, improvement in upper extremity ischemia, steal syndrome, left-right blood pressure difference, and perioperative complications) and the results after 30 postoperative days (incidence of vertebrobasilar artery territory infarction and restenosis). Stent placement and vessel dilatation were successful in all patients, without perioperative complications. Upper extremity ischemia, steal syndrome, and left-right blood pressure difference disappeared in all cases. During follow-up observation (6-96 months
median 51 months), no restenosis occurred at the stent placement site in any patient. In one case, four years after initial treatment, stenosis was noted proximal to the stent placement site. Satisfactory long-term as well as short-term outcomes were achieved after stent placement for SA obstructive lesions assisted by intraoperative IVUS evaluation.

DOI： 10.15274/NRJ-2014-10023

Long-term treatment outcomes after intravascular ultrasound evaluation and stent placement for atherosclerotic subclavian artery obstructive lesions

Wada T., Takayama K., Taoka T., Nakagawa H., Myouchin K., Miyasaka T., Akashi T., Sakamoto M., Kichikawa K.

Neuroradiology Journal Vol. 27 ( 2 ) page： 213 - 221 2014.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Neuroradiology Journal

The objective of this study was to determine long-term outcomes after stent placement for subclavian artery (SA) obstructive lesions assisted by intraoperative intravascular ultrasound (IVUS). The study included 25 lesions in 24 patients who underwent stent placement assisted by intraoperative IVUS for subclavian artery stenosis or obstruction at our hospital between January 2003 and August 2010. Outcome was evaluated based on the results within 30 postoperative days (technical success rate, improvement in upper extremity ischemia, steal syndrome, left-right blood pressure difference, and perioperative complications) and the results after 30 postoperative days (incidence of vertebrobasilar artery territory infarction and restenosis). Stent placement and vessel dilatation were successful in all patients, without perioperative complications. Upper extremity ischemia, steal syndrome, and left-right blood pressure difference disappeared in all cases. During follow-up observation (6-96 months; median 51 months), no restenosis occurred at the stent placement site in any patient. In one case, four years after initial treatment, stenosis was noted proximal to the stent placement site. Satisfactory long-term as well as short-term outcomes were achieved after stent placement for SA obstructive lesions assisted by intraoperative IVUS evaluation.

DOI： 10.15274/NRJ-2014-10023

Cerebellar dentate nucleus in progressive supranuclear palsy International journal

Nobuhiro Sawa, Hiroshi Kataoka, Takao Kiriyama, Tesseki Izumi, Toshiaki Taoka, Kimihiko Kichikawa, Satoshi Ueno

CLINICAL NEUROLOGY AND NEUROSURGERY Vol. 118 page： 32 - 6 2014.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Objectives: Some patients with progressive supranuclear palsy (PSP) present with cerebellar dysfunction. Severe degeneration of the cerebellar dentate nucleus (CDN) was evident in these patients. We evaluated signal intensity on MRI in the CDN of PSP patients with or without cerebellar ataxia.
Patients and methods: We reviewed the clinical histories and brain MRI studies of 28 patients with clinically probable PSP. Three disease control groups were studied: a group of 28 sex- and age-matched patients with Parkinson's disease (PD), a group of 15 patients with multiple system atrophy with predominant parkinsonian features (MSA-P), and 15 control subjects. Turbo spin-echo sequences for T2-weighted images were used using a 1.5 T magnetic resonance imager.
Results: Eight patients with PSP (28%) and one patient with MSA-P (6%) had heterogeneous regions in the CDN. This finding was not evident in the patients with PD or controls. Three out of four PSP patients with cerebellar ataxia had heterogeneous regions in the CDN and other one patient with cerebellar ataxia as the initial and principal symptoms had no heterogeneous regions in the CDN.
Conclusion: Heterogeneous regions in the CDN on MRI do not always reflect cerebellar ataxia in PSP patients, and this finding might be an additional marker to support a probable diagnosis of PSP. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.clineuro.2013.12.011

Decision-making deficit of a patient with axonal damage after traumatic brain injury

Fumihiko Yasuno, Kiwamu Matsuoka, Soichiro Kitamura, Kuniaki Kiuchi, Jun Kosaka, Koji Okada, Syohei Tanaka, Takayuki Shinkai, Toshiaki Taoka, Toshifumi Kishimoto

BRAIN AND COGNITION Vol. 84 ( 1 ) page： 63 - 8 2014.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Patients with traumatic brain injury (TBI) were reported to have difficulty making advantageous decisions, but the underlying deficits of the network of brain areas involved in this process were not directly examined. We report a patient with TBI who demonstrated problematic behavior in situations of risk and complexity after cerebral injury from a traffic accident. The Iowa gambling task (IGT) was used to reveal his deficits in the decision-making process. To examine underlying deficits of the network of brain areas, we examined T1-weighted structural MRI, diffusion tensor imaging (DTI) and Tc-ECD SPECT in this patient. The patient showed abnormality in IGT. DTI-MRI results showed a significant decrease in fractional anisotropy (FA) in the fasciculus between the brain stem and cortical regions via the thalamus. He showed significant decrease in gray matter volumes in the bilateral insular cortex, hypothalamus, and posterior cingulate cortex, possibly reflecting Wallerian degeneration secondary to the fasciculus abnormalities. SPECT showed significant blood flow decrease in the broad cortical areas including the ventromedial prefrontal cortex (VM). Our study showed that the patient had dysfunctional decision-making process. Microstructural abnormality in the fasciculus, likely from the traffic accident, caused reduced afferent feedback to the brain, resulting in less efficient decision-making. Our findings support the somatic-marker hypothesis (SMH), where somatic feedback to the brain influences the decision-making process. (C) 2013 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bandc.2013.11.005

Comparison between Two Separate Injections and a Single Injection of Double-dose Contrast Medium for Contrast-enhanced MR Imaging of Metastatic Brain Tumors

Tomoko Ochi, Toshiaki Taoka, Ryosuke Matsuda, Masahiko Sakamoto, Toshiaki Akashi, Tetsuro Tamamoto, Tadashi Sugimoto, Hiroshi Sakaguchi, Masatoshi Hasegawa, Hiroyuki Nakase, Kimihiko Kichikawa

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 13 ( 4 ) page： 221 - 9 2014

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE

Purpose: As stereotactic radiotherapy (SRT) becomes widespread, precise information including number, location, and margin of lesions is required when magnetic resonance (MR) imaging of brain metastasis is performed. We compare methods using 2 separate injections and a single injection for the administration of a double dose of contrast medium for contrastenhanced MR imaging.
Materials and Methods: We divided 40 patients with brain metastasis into 2 groups of 20 patients. Group A received 2 separate injections (0.2 + 0.2 mL/kg) of contrast medium (gadoteridol); Group B received a single injection of the same total dose (0.4 mL/kg). Group A underwent spin echo (SE) T-1-weighted imaging (T1WI) and magnetization prepared rapid acquisition with gradient echo sequence (MPRAGE) after each injection, and Group B underwent the same MR studies at the same timing as Group A. We evaluated the number, signal-to-noise ratio (SNR), diameter, margin delineation, and volume of lesions and compared them between early and delayed studies by the 2 methods.
Results: The number of detected lesions was largest in delayed studies of MPRAGE in both groups. The SNR of the lesions was statistically lower in early studies of Group A than other studies. Delayed studies of Group B showed statistically better margin delineation than other studies on both SE-T1WI and MPRAGE studies. Diameter and enhanced volume were statistically significantly larger on delayed phase than early phase in both groups.
Conclusion: Use of a single injection of double-dose contrast medium and longer delay time may improve margin delineation of lesions for the study of brain metastasis. Enhanced volume was larger on delayed phase, and it may influence selection of therapeutic strategy.

DOI： 10.2463/mrms.2013-0068

Gray and White Matter Changes in Subjective Cognitive Impairment, Amnestic Mild Cognitive Impairment and Alzheimer's Disease: A Voxel-Based Analysis Study

Kuniaki Kiuchi, Soichiro Kitamura, Toshiaki Taoka, Fumihiko Yasuno, Masami Tanimura, Kiwamu Matsuoka, Daisuke Ikawa, Michihiro Toritsuka, Kazumichi Hashimoto, Manabu Makinodan, Jun Kosaka, Masayuki Morikawa, Kimihiko Kichikawa, Toshifumi Kishimoto

PLOS ONE Vol. 9 ( 8 ) page： e104007 2014

Language：English Publishing type：Research paper (scientific journal) Publisher：PUBLIC LIBRARY SCIENCE

Subjective cognitive impairment may be a very early at-risk period of the continuum of dementia. However, it is difficult to discriminate at-risk states from normal aging. Thus, detection of the early pathological changes in the subjective cognitive impairment period is needed. To elucidate these changes, we employed diffusion tensor imaging and volumetry analysis, and compared subjective cognitive impairment with normal, mild cognitive impairment and Alzheimer's disease. The subjects in this study were 39 Alzheimer's disease, 43 mild cognitive impairment, 28 subjective cognitive impairment and 41 normal controls. There were no statistically significant differences between the normal control and subjective cognitive impairment groups in all measures. Alzheimer's disease and mild cognitive impairment had the same extent of brain atrophy and diffusion changes. These results are consistent with the hypothetical model of the dynamic biomarkers of Alzheimer's disease.

DOI： 10.1371/journal.pone.0104007

Effective second stent placement on down-the-barrel view for a stent assisted coil embolization of vertebral artery fusiform aneurysm: case report

Successful intravenous rt-PA treatment for a patient with basilar artery occlusion manifesting ischemic neurogenic stunned myocardium and ataxic breathing. Reviewed

Tomoyuki Taguchi, Masayuki Fujioka, Shingo Ito, Yasushi Motoyama, Hiroyuki Nakase, Toshiaki Taoka, Kazuo Okuchi

Neurosurgical Emergency Vol. 19 page： 220 - 225 2014

WADA Takeshi, TAKAYAMA Katsutoshi, TAOKA Toshiaki, NAKAGAWA Hiroyuki, MYOUCHIN Kaoru, KIMURA Ryouta, KUROKAWA Shinichiro, KICHIKAWA Kimihiko

Journal of Neuroendovascular Therapy Vol. 8 ( 4 ) page： 218 - 223 2014

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Neuroendovascular Therapy

Objective: We report a case of a fusiform aneurysm of vertebral artery, treated by second stent placement using stent-in-stent technique on down-the-barrel view (DBV) for a stent assisted coil embolization. Case presentation: A 60-year-old woman had a fusiform aneurysm of the right vertebral artery growing up in size during 1 year follow up. Stent-assisted coil embolization using an Enterprise stent was performed. During coil embolization with the initial Enterprise stent, coil migration to the parent artery was seen on DBV. The second Enterprise stent was deployed in a stent-in-stent manner. Following deployment of the second stent, coil migration to the parent artery disappeared with preserving the vessel lumen. Complete occlusion of the aneurysm and good patency of the parent artery were seen on 3 months’ follow up angiogram. Conclusion: Second stent placement using stent-in-stent technique may be effective for management of coil herniation to the parent vessel during stent-assist coil embolization for fusiform vertebral artery aneurysm.

DOI： 10.5797/jnet.cr.13050

A Mismatch Between the Abnormalities in Diffusion- and Susceptibility-Weighted Magnetic Resonance Imaging May Represent an Acute Ischemic Penumbra with Misery Perfusion International journal

Masayuki Fujioka, Kazuo Okuchi, Asami Iwamura, Toshiaki Taoka, Bo K. Siesjo

JOURNAL OF STROKE & CEREBROVASCULAR DISEASES Vol. 22 ( 8 ) page： 1428 - 31 2013.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Susceptibility-weighted imaging (SWI) has recently attracted attention for its ability to investigate acute stroke pathophysiology. SWI detects an increased ratio of deoxyhemoglobin to oxyhemoglobin in cerebral venous compartments, which can illustrate cerebral misery perfusion with a compensatory increase of oxygen extraction fraction in the hypoperfused brain. In this study we make the first case report of blunt cervical trauma leading to a stroke, demonstrating the disparity between diffusion-weighted imaging (DWI) and SWI changes, or DWI-SWI mismatch, in the acute ischemic brain. The area of mismatch between a smaller DWI cytotoxic edema and a larger SWI misery perfusion in our patient matured into a complete infarction with time. The DWI-SWI mismatch may signify the presence of an ischemic penumbra, and provide information about viability of the brain tissue at risk of potential infarction if without early reperfusion.

DOI： 10.1016/j.jstrokecerebrovasdis.2012.12.009

Unilateral oculomotor nerve palsy as an initial presentation of bilateral chronic subdural hematoma: Case report

Matsuda R., Hironaka Y., Kawai H., Park Y., Taoka T., Nakase H.

Neurologia Medico-Chirurgica Vol. 53 ( 9 ) page： 616 - 619 2013.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Neurologia Medico-Chirurgica

Isolated oculomotor nerve palsy is well known as a symptom of microvascular infarction and intracranial aneurysm, but unilateral oculomotor nerve palsy as an initial manifestation of chronic subdural hematoma (CSDH) is a rare clinical condition. We report a rare case of an 84-year-old woman with bilateral CSDH who presented with unilateral oculomotor nerve palsy as the initial symptom. The patient, who had a medical history of minor head injury 3 weeks prior, presented with left ptosis, diplopia, and vomiting. She had taken an antiplatelet drug for lacunar cerebral infarction. Computed tomography (CT) of the head showed bilateral CSDH with a slight midline shift to the left side. She underwent an urgent evacuation through bilateral frontal burr holes. Magnetic resonance angiography (MRA) after evacuation revealed no intracranial aneurysms, but constructive interference in steady-state (CISS) magnetic resonance imaging (MRI) revealed that the left posterior cerebral artery (PCA) ran much more anteriorly and inferiorly compared with the right PCA and the left oculomotor nerve passed very closely between the left PCA and the left superior cerebellar artery (SCA). There is the possibility that the strong compression to the left uncus, the left PCA, and the left SCA due to the bilateral CSDH resulted in left oculomotor nerve palsy with an initial manifestation without unconsciousness. Unilateral oculomotor nerve palsy as an initial presentation caused by bilateral CSDH without unconsciousness is a rare clinical condition, but this situation is very important as a differential diagnosis of unilateral oculomotor nerve palsy. © 2013 by The Japan Neurosurgical Society.

DOI： 10.2176/nmc.cr2012-0339

Unilateral Oculomotor Nerve Palsy as an Initial Presentation of Bilateral Chronic Subdural Hematoma: Case Report Reviewed

Ryosuke Matsuda, Yasuo Hironaka, Hisashi Kawai, Young-Su Park, Toshiaki Taoka, Hiroyuki Nakase

NEUROLOGIA MEDICO-CHIRURGICA Vol. 53 ( 9 ) page： 616 - 619 2013.9

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN NEUROSURGICAL SOC

Isolated oculomotor nerve palsy is well known as a symptom of microvascular infarction and intracranial aneurysm, but unilateral oculomotor nerve palsy as an initial manifestation of chronic subdural hematoma (CSDH) is a rare clinical condition. We report a rare case of an 84-year-old woman with bilateral CSDH who presented with unilateral oculomotor nerve palsy as the initial symptom. The patient, who had a medical history of minor head injury 3 weeks prior, presented with left ptosis, diplopia, and vomiting. She had taken an antiplatelet drug for lacunar cerebral infarction. Computed tomography (CT) of the head showed bilateral CSDH with a slight midline shift to the left side. She underwent an urgent evacuation through bilateral frontal burr holes. Magnetic resonance angiography (MRA) after evacuation revealed no intracranial aneurysms, but constructive interference in steady-state (CISS) magnetic resonance imaging (MM) revealed that the left posterior cerebral artery (PCA) ran much more anteriorly and inferiorly compared with the right PCA and the left oculomotor nerve passed very closely between the left PCA and the left superior cerebellar artery (SCA). There is the possibility that the strong compression to the left uncus, the left PCA, and the left SCA due to the bilateral CSDH resulted in left oculomotor nerve palsy with an initial manifestation without unconsciousness. Unilateral oculomotor nerve palsy as an initial presentation caused by bilateral CSDH without unconsciousness is a rare clinical condition, but this situation is very important as a differential diagnosis of unilateral oculomotor nerve palsy.

DOI： 10.2176/nmc.cr2012-0339

Longitudinal white matter changes in Alzheimer's disease: A tractography-based analysis study

Soichiro Kitamura, Kuniaki Kiuchi, Toshiaki Taoka, Kazumichi Hashimoto, Shotaro Ueda, Fumihiko Yasuno, Masayuki Morikawa, Kimihiko Kichikawa, Toshifumi Kishimoto

BRAIN RESEARCH Vol. 1515 page： 12 - 8 2013.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Alzheimer's disease (AD) classically presents with gray matter atrophy, as well as feature significant white matter abnormalities. Previous evidence indicates the overall burden of these pathological changes continues to advance as the disease progresses. The aim of this study was to investigate whether pathological alterations of white matter tracts correlate with the course of AD disease progression. 35 AD patients and 29 normal controls were recruited to the study and administered baseline magnetic resonance diffusion tensor imaging (DTI) acquisition and a cognitive function assessment at the time of initial evaluation. Subjects were re-evaluated with secondary DTI scan and cognitive function assessment at intervals of about 1.5 years on average. For the DTI acquired scans, we calculated diffusion tensor parameters, fractional anisotropy (FA), apparent diffusion coefficient (ADC), radial diffusivity (DR), and axial diffusivity (DA) along with the uncinate fasciculus (UNC), the inferior longitudinal fasciculus (ILF), and the inferior occipitofrontal fasciculus (IOFF). Compared to baseline, a significant mean FA reduction of the bilateral UNC, as well as a significant mean DR increase of the left UNC, was evident in AD patients at follow-up. Compared with normal controls, AD patients exhibited significant diffusion parameter abnormalities in their UNC, ILF, and IOFF. Taken together, these results indicate that progressive pathological white matter alterations can be quantified using the DTI parameters utilized here and may prove to be a useful biological marker for monitoring the pathophysiological course of AD. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.brainres.2013.03.052

Unilateral Optic Nerve Hypoplasia with Contralateral Optic Pathway Hypoplasia: A Case Report Reviewed International journal

Tomo Nishi, Eiichi Yukawa, Toshiaki Taoka, Nahoko Ogata

NEURO-OPHTHALMOLOGY Vol. 37 ( 3 ) page： 116 - 119 2013.6

Language：English Publishing type：Research paper (scientific journal) Publisher：INFORMA HEALTHCARE

Optic nerve hypoplasia is diagnosed by the ophthalmoscopic appearance of the fundus of the eye and by standard magnetic resonance imaging of the brain. The ability to study eyes with optic nerve hypoplasia by magnetic resonance diffusion tensor imaging has improved the evaluation of the optic pathways. The authors report a case of unilateral optic nerve hypoplasia with hypoplasia of the contralateral optic pathway. The entire visual pathway of this patient was examined by magnetic resonance and magnetic resonance diffusion tensor imaging. The images show a decrease of the volume of the optic radiation contralateral to the optic nerve abnormality and also pre- and post-chiasmal abnormalities.

DOI： 10.3109/01658107.2013.785572

Transient Global Brain Ischemia Induces Striatal Neuronal Death of T1-Hyperintensity without Hemorrhage: Susceptibility-Weighted Imaging Study on Cardiac Arrest Survivors Reviewed

Semi-Jailing法が有用であったEnterprise sentを用いた内頸動脈瘤の2例

和田敬, 高山勝年, 中川裕之, 宮坂俊輝, 明珍薫, 坂本雅彦, 田岡俊昭, 吉川公彦, 中川一郎, 黒川紳一郎

IVR: Interventional Radiology Vol. 28 ( Suppl. ) page： 155 - 155 2013.4

Movement Disorders in Golfers Reviewed

Samish Dhungana, Joseph Jankovic

NEUROLOGY Vol. 80 page： 675 - 709 2013.2

Masayuki Fujioka, Tomoo Watanabe, Toshiaki Taoka, Kazuo Okuchi

STROKE Vol. 44 ( 2 ) 2013.2

脳幹背側症候群が疑われた一新生児例

堀沙恵香, 田岡俊昭, 明石敏昭, 坂本雅彦, 和田敬, 吉川公彦, 越智朋子, 内田優美子, 高橋幸博

Japanese Journal of Radiology Vol. 31 ( Suppl.I ) page： 58 - 58 2013.2

The Use of Susceptibility-Weighted Imaging as an Indicator of Retrograde Leptomeningeal Venous Drainage and Venous Congestion With Dural Arteriovenous Fistula: Diagnosis and Follow-up After Treatment

Ichiro Nakagawa, Toshiaki Taoka, Takeshi Wada, Hiroyuki Nakagawa, Masahiko Sakamoto, Kimihiko Kichikawa, Yasuo Hironaka, Yasushi Motoyama, Young-Su Park, Hiroyuki Nakase

NEUROSURGERY Vol. 72 ( 1 ) page： 47 - 54; discussion 55 2013.1

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

BACKGROUND: Retrograde leptomeningeal venous drainage (RLVD) in dural arteriovenous fistulas (DAVFs) is associated with intracerebral hemorrhage and non-hemorrhagic neurological deficits or death. Angiographic evidence of RLVD is a definite indication for treatment, but less invasive methods of identifying RLVD are required.
OBJECTIVE: To evaluate the efficacy of susceptibility-weighted magnetic resonance imaging (SWI) in detecting RLVD in DAVFs.
METHODS: We retrospectively identified 17 DAVF patients who had angiographic evidence of RLVD and received treatment. Conventional angiography and SWI were assessed at pretreatment and posttreatment time points. The presence of RLVD on SWI was defined as cortical venous hyperintensity, and the presence of venous congestion on SWI venograms was defined as increased caliber of cortical or medullary veins.
RESULTS: Cortical venous hyperintensity was identified in pretreatment SWI of 15 patients. Cortical venous hyperintensity was absent in early posttreatment SWI, consistent with the absence of RLVD in posttreatment angiography, in all but one of these patients. In 2 patients, cortical venous hyperintensity was identified during follow-up, indicating the recurrence of RLVD. Cortical venous hyperintensity was not identified in the pretreatment SWI of 2 patients despite angiographic evidence of RLVD. Venous congestion was identified in pretreatment SWI venograms of 11 patients and had an appearance similar to that identified from angiography. Venous congestive signs improved over the follow-up period.
CONCLUSION: The presence of SWI hyperintensity within the venous structure could be a useful indicator of RLVD in DAVF patients. Thus, SWI offers a noninvasive alternative to angiography for the identification of RLVD in pretreated and posttreated DAVF patients.

DOI： 10.1227/NEU.0b013e318276f7cc

Carotid Wallstent placement difficulties encountered in carotid artery stenting Reviewed International journal

Kaoru Myouchin, Katsutoshi Takayama, Toshiaki Taoka, Hiroyuki Nakagawa, Takeshi Wada, Masahiko Sakamoto, Satoru Iwasaki, Shinichiro Kurokawa, Kimihiko Kichikawa

SPRINGERPLUS Vol. 2 ( 1 ) page： 468 - 468 2013

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER INTERNATIONAL PUBLISHING AG

Purpose: The present study aimed to identify the types of curved lesions that are difficult to place Carotid Wallstent (CWS).
Materials and methods: The study targeted 31 consecutive carotid artery (CA) stenosis underwent carotid artery stenting using CWS. CWS placement success rate, stenosis location, lesion tortuosity, and relationship with stent placement failures were investigated. Lesion tortuosity was defined as the angle formed by 2 tangential lines between internal CA and common CA from the inflection point (IP) was defined as the center of lesion curvature. Stenosed lesions were classified into type A or B. Type A was defined as if the distal end of the stenosis was located proximal to the IP at a distance >= 0.5 of a vertebral body based on the posterior height of the 3rd vertebral body, otherwise was type B.
Results: The stent placement success rate was 93.5% (29/31). The 2 unsuccessfully stented lesions, both lesions were significantly different from other lesions by having a lesion tortuosity less than 90 degrees and by belonging to type B.
Conclusion: Since CWS placement is difficult in patients with CA stenosis located close to the IP at a lesion tortuosity <= 90 degrees, open-cell stents should be considered as an alternative.

DOI： 10.1186/2193-1801-2-468

Obstacles encountered during transradial angiography from after radial artery puncture to the aortic arch International journal

Satoru Iwasaki, Kazuhiro Yokoyama, Kinya Furuichi, Hiroshi Okada, Akira Ohkura, Koichi Ide, Katsutoshi Takayama, Toshiaki Taoka, Kimihiko Kichikawa

SpringerPlus Vol. 2 ( 1 ) page： 1 - 8 2013

Language：English Publishing type：Research paper (scientific journal)

Objective: To elucidate the key points for safe performance of transradial angiography. Conclusions: Transradial angiography can be performed safely if attention is paid to the following points from after radial artery puncture to reaching the aortic arch: resistance during guide wire operation for sheath insertion after puncture
confirmation of the superficial brachial artery
guide wire resistance while guiding the catheter to the aortic arch
and aortic arch anomalies. © 2013 Iwasaki et al.

DOI： 10.1186/2193-1801-2-365

Unilateral Oculomotor Nerve Palsy as an Initial Presentation of Bilateral Chronic Subdural Hematoma: Case Report

MATSUDA Ryosuke, HIRONAKA Yasuo, KAWAI Hisashi, PARK Young-Su, TAOKA Toshiaki, NAKASE Hiroyuki

Neurologia medico-chirurgica Vol. 53 ( 9 ) page： 616 - 9 2013

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Neurosurgical Society

DOI： 10.2176/nmc.cr2012-0339

Pre-operative tractography of the facial nerve in vestibular schwannomas: inter-observer agreement with surgical findings Reviewed

Gon{\c{c } }alves Pereira Pedro, Neto d'Almeida G, Escada P, Mana{\c{c } }as Rui, Taoka T

2013

Accuracy for predicting adhesion between meningioma and the brain by using brain surface motion imaging: comparison between single and double acquisition methods

Toshiaki Taoka, Syuichi Yamada, Masahiko Sakamoto, Toshiaki Akashi, Toshiteru Miyasaka, Tomoko Ochi, Takeshi Wada, Masato Uchikoshi, Hiroyuki Nakase, Kimihiko Kichikawa

NEURORADIOLOGY Vol. 54 ( 12 ) page： 1313 - 20 2012.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The presence of adhesions between the brain and the meningioma is an important factor that determines the success of total surgical removal. Brain surface motion imaging enables assessment of the dynamics of brain surface motion. A subtraction image of pulse-gated heavily T2-weighted images in different phases of the cardiac cycle provides a stripe pattern on the surface of the pulsating brain. Thus, the lack of a stripe pattern on the surface of extraaxial tumor indicates the presence of tumor-brain adhesion. The purpose of the present experiment was to evaluate the accuracy of predicting tumor-brain adhesion using the original double acquisition method and the improved single acquisition method.
The subjects were 67 meningioma cases patients who were surgically treated after brain surface motion imaging. Thirty-three cases were evaluated using the double acquisition method and 34 cases were evaluated with the single acquisition method. In the double acquisition method, the two sets of images are acquired as two independent scans, and in the single acquisition method, the images are acquired serially as a single scan.
The findings for the double acquisition method agreed with the surgical findings in 23 cases (69.7 %), while findings from the single acquisition method agreed with the surgical findings in 26 cases (76.5 %).
Pre-surgical evaluation for tumor-brain adhesion by brain surface motion imaging provides helpful information for meningioma surgery, especially when using the single acquisition method.

DOI： 10.1007/s00234-012-1054-4

Effect of Cilostazol in Preventing Restenosis after Carotid Artery Stenting Using the Carotid Wallstent: A Multicenter Retrospective Study

K. Takayama, T. Taoka, H. Nakagawa, K. Myouchin, T. Wada, M. Sakamoto, K. Furuichi, S. Iwasaki, S. Kurokawa, K. Kichikawa

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 33 ( 11 ) page： 2167 - 2170 2012.12

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: Restenosis after CAS is a postoperative problem, with a reported frequency of approximately 2%-8%. However differences in stent design, procedure, and the antiplatelet agent appear to affect the incidence of restenosis. We assessed the frequency of restenosis and the effect of the antiplatelet agent CLZ in preventing restenosis after CAS by the standard procedure using the CWS.
MATERIALS AND METHODS: Between May 2010 and October 2011, 62 lesions in 60 consecutive patients underwent CAS using the CWS at 4 medical institutions, and all patients were followed clinically and assessed by sonography, 3D-CTA, or angiography at 3 and 6 months postoperatively. Restenosis was defined as >= 50% stenosis. The incidence of restenosis and the variation in the incidence of restenosis by the difference in type of antiplatelet agent between the CLZ group (n = 30; aspirin, 100 mg, and CLZ, 200 mg) and the non-CLZ group (n = 32; aspirin, 100 mg, and clopidogrel, 75 mg [n = 29]; or ticlopidine, 100 mg [n = 2] or 200 mg [n = 1]) were retrospectively investigated. Two antiplatelet agents were given starting 1 week preoperatively until at least 3 months postoperatively.
RESULTS: Restenosis occurred in 5 patients (8.3%), but all were cases of asymptomatic lesions in the follow-up period. All 5 patients with restenosis were in the non-CLZ group, with no cases of restenosis in the CLZ group; the difference was significant (P = .0239).
CONCLUSIONS: The restenosis rate after CAS by using the CWS was 8.3%. CLZ was associated with significant inhibition of restenosis.

DOI： 10.3174/ajnr.A3127

Visualizing non-Gaussian diffusion: Clinical application of q-space imaging and diffusional kurtosis imaging of the brain and spine

Hori M., Fukunaga I., Masutani Y., Taoka T., Kamagata K., Suzuki Y., Aoki S.

Magnetic Resonance in Medical Sciences Vol. 11 ( 4 ) page： 221 - 233 2012.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Magnetic Resonance in Medical Sciences

Recently, non-Gaussian diffusion-weighted imaging (DWI) techniques, including qspace imaging (QSI) and diffusional kurtosis imaging (DKI), have emerged as advanced methods to evaluate tissue microstructure in vivo using water diffusion. QSI and DKI have shown promising results in clinical applications, such as in the evaluation of brain tumors (e.g., grading gliomas), degenerative diseases (e.g., specific diagnosis of Parkinson disease), demyelinating diseases (e.g., assessment of normal-appearing tissue of multiple sclerosis), and cerebrovascular diseases (e.g., assessment of the microstructural environment of fresh infarctions). Representative metrics in clinical use are the full width at half maximum, also known as the mean displacement of the probability density function curve, which is derived from QSI, and diffusional kurtosis, which is derived from DKI. These new metrics may provide information on tissue structure in addition to that provided by conventional Gaussian DWI investigations that use the apparent diffusion coefficient and fractional anisotropy, recognized indices for evaluating disease and normal development in the brain and spine. In some clinical situations, sensitivity for detecting pathological conditions is higher using QSI and DKI than conventional DWI and diffusion tensor imaging (DTI) because DWI and DTI calculations are based on the assumption that water molecules follow a Gaussian distribution, whereas hindrance of the distribution of water molecules by complex and restricted structures in actual neural tissues produces distributions that are far from Gaussian. We review the technical aspects and clinical applications of QSI and DKI, focusing on clinical use and in vivo studies and highlighting differences from conventional diffusional metrics.

DOI： 10.2463/mrms.11.221

Brain structural changes and neuropsychological impairments in male polydipsic schizophrenia

Tomohisa Nagashima, Makoto Inoue, Soichiro Kitamura, Kuniaki Kiuchi, Jun Kosaka, Koji Okada, Naoko Kishimoto, Toshiaki Taoka, Kimihiko Kichikawa, Toshifumi Kishimoto

BMC PSYCHIATRY Vol. 12 ( 1 ) page： 210 2012.11

Language：English Publishing type：Research paper (scientific journal) Publisher：BIOMED CENTRAL LTD

Background: Polydipsia frequently occurs in schizophrenia patients. The excessive water loading in polydipsia occasionally induces a hyponatremic state and leads to water intoxication. Whether polydipsia in schizophrenic patients correlates with neuropsychological impairments or structural brain changes is not clear and remains controversial.
Methods: Eight polydipsic schizophrenia patients, eight nonpolydipsic schizophrenia patients, and eight healthy controls were recruited. All subjects underwent magnetic resonance imaging (MRI) and neuropsychological testing. Structural abnormalities were analyzed using a voxel-based morphometry (VBM) approach, and patients' neuropsychological function was assessed using the Brief Assessment of Cognition in Schizophrenia, Japanese version (BACS-J).
Results: No significant differences were found between the two patient groups with respect to the clinical characteristics. Compared with healthy controls, polydipsic patients showed widespread brain volume reduction and neuropsychological impairment. Furthermore, the left insula was significantly reduced in polydipsic patients compared with nonpolydipsic patients. These nonpolydipsic patients performed intermediate to the other two groups in the neuropsychological function test.
Conclusions: It is possible that polydipsia or the secondary hyponatremia might induce left insula volume reduction. Furthermore, this structural brain change may indirectly induce more severe neuropsychological impairments in polydipsic patients. Thus, we suggest that insula abnormalities might contribute to the pathophysiology of polydipsic patients.

DOI： 10.1186/1471-244X-12-210

Application of susceptibility weighted imaging (SWI) for evaluation of draining veins of arteriovenous malformation: utility of magnitude images

Toshiteru Miyasaka, Toshiaki Taoka, Hiroyuki Nakagawa, Takeshi Wada, Katsutoshi Takayama, Kaoru Myochin, Masahiko Sakamoto, Tomoko Ochi, Toshiaki Akashi, Kimihiko Kichikawa

NEURORADIOLOGY Vol. 54 ( 11 ) page： 1221 - 7 2012.11

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The current study evaluated the signal characteristics of susceptibility weighted imaging (SWI) of arteriovenous malformation (AVM), especially for draining veins. For this purpose, we identified the draining veins of the AVM on angiography and evaluated the signal on magnitude image for SWI (SWI-mag) and minimum intensity projection image (SWI-minIP).
Subjects were 14 cases with angiographically proven AVM. SWI-mag, SWI-minIP, and time-of-flight (TOF) magnetic resonance angiography were acquired. For the draining veins of the AVM identified on angiography, we analyzed signal intensity on the images listed above, and classified it into hyperintensity (hyper), mixed intensity (mixed), hypointensity (hypo), and no visualization.
On the analysis of 27 angiographically proven draining veins, 19 draining veins were classified as hyper, 3 as mixed, 0 as hypo, and 6 as no visualization on SWI-mag. On TOF images, 21 draining veins were classified as hyper, 2 as mixed, 0 as hypo, and 4 as no visualization, while 6 draining veins did not show hyperintensity on TOF, and SWI-mag visualized 3 of these 6 veins as hyper.
SWI-mag depicted most draining veins of AVM as hyperintensity. We speculate that this is mainly due to the higher concentration of oxygenated hemoglobin (oxy-Hb) and inflow effect of the draining vein. SWI-mag seems to be useful in the analysis and follow-up for AVM as the signal on the image may reflect physiological status.

DOI： 10.1007/s00234-012-1029-5

頭蓋内静脈逆流を伴う硬膜動静脈瘻におけるSusceptibility-Weighted Imagingの有用性治療前後での頭蓋内静脈逆流と静脈うっ血の評価

中川一郎, 和田敬, 中川裕之, 西村文彦, 弘中康雄, 本山靖, 朴永銖, 田岡俊昭, 吉川公彦, 中瀬裕之

JNET: Journal of Neuroendovascular Therapy Vol. 6 ( 5 ) page： 233 - 233 2012.11

Investigation of donepezil effect to the prevention of hippocamal volume loss in alzheimer's disease Reviewed

S. Kitamura, K. Kiuchi, T. Taoka, M. Morikawa, M. Inoue, J. Kosaka, K. Hashimoto, T. Nagashima, K. Matsuoka, K. Kichikawa, T. Kishimoto

INTERNATIONAL JOURNAL OF NEUROPSYCHOPHARMACOLOGY Vol. 15 page： 172 - 173 2012.6

Branching pattern of lenticulostriate arteries observed by MR angiography at 3.0 T

Toshiaki Akashi, Toshiaki Taoka, Tomoko Ochi, Toshiteru Miyasaka, Takeshi Wada, Masahiko Sakamoto, Megumi Takewa, Kimihiko Kichikawa

JAPANESE JOURNAL OF RADIOLOGY Vol. 30 ( 4 ) page： 331 - 5 2012.5

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

We hypothesized that the pattern of branching of the lenticulostriate arteries (LSAs) is involved in the variation of the distribution of the infarction within the LSA region. Our purpose was to evaluate the visibility of LSAs in 3D time-of-flight (TOF) MR angiography (MRA) with a 3.0 T scanner and to investigate the branching patterns of LSAs.
We performed 3D TOF MRA at 3.0 T for 100 healthy subjects. We assessed the number of LSAs and the number of branches arising from each LSA by evaluating MRA source images.
In 200 hemispheres, 330 LSAs were visualized (mean = 1.65/hemisphere). In 3.5% of all hemispheres, no LSA was depicted; one LSA was depicted in 39%, two in 46.5%, and three in 11%. The maximum number of depicted LSA branches was five in 2% of all subjects, four in 7%, three in 26%, and two in 49% (mean = 2.3/subject). A large LSA trunk with three or more branches was found in 35% of subjects.
Visualization of LSAs was possible in 96.5% of subjects by use of 3.0 T MRA. LSA branching patterns were variable, and a large LSA trunk with three or more branches was common.

DOI： 10.1007/s11604-012-0058-7

Diffuse vascular injury: convergent-type hemorrhage in the supratentorial white matter on susceptibility-weighted image in cases of severe traumatic brain damage

Asami Iwamura, Toshiaki Taoka, Akio Fukusumi, Masahiko Sakamoto, Toshiteru Miyasaka, Tomoko Ochi, Toshiaki Akashi, Kazuo Okuchi, Kimihiko Kichikawa

NEURORADIOLOGY Vol. 54 ( 4 ) page： 335 - 43 2012.4

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Susceptibility-weighted image (SWI) is one of the most sensitive methods for detect microbleeding and useful for evaluation of traumatic brain damage. The purpose of this study is to delineate the characteristics and importance of supratentorial deep white matter hemorrhages detected by SWI in cases of traumatic brain damage.
Twenty-one consecutive cases with severe traumatic head injury were included in the current study. MRI examinations were made within 1 month after injury. We evaluated the degree and distribution of the supratentorial hemorrhages on SWI retrospectively. We classified the degree of bleeding into four grades: "small hemorrhage," "single bead-like hemorrhage," "convergent-type hemorrhage," and "massive hemorrhage." We then correlated the degree and distribution of the hemorrhage to clinical outcomes. We also evaluated the apparent diffusion coefficient (ADC) image of lobes with "convergent-type hemorrhage."
Existence of "massive hemorrhage" correlated with a poor outcome, that is, worse than "severely disabled" on the Glasgow Outcome Scale. The number of lobes affected by "convergent-type hemorrhage" also correlated with poor outcome. There were 45 lobes with "convergent-type hemorrhage" and 27 of them showed increased diffusivity on ADC images.
Supratentorial massive hemorrhages and supratentorial convergent-type multiple hemorrhages were associated with poor prognosis after traumatic brain injury. The increased diffusivity in lobes with convergent-type hemorrhages may indicate that congestion of the proximal medullary vein may play some role for these hemorrhages.

DOI： 10.1007/s00234-011-0892-9

Comparison of Computed Tomography Myelography and Radioisotope Cisternography to Detect Cerebrospinal Fluid Leakage in Spontaneous Intracranial Hypotension

Keiji Hashizume, Keisuke Watanabe, Masahiko Kawaguchi, Toshiaki Taoka, Takayuki Shinkai, Hitoshi Furuya

SPINE Vol. 37 ( 4 ) page： E237 - 42 2012.2

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Study Design. A retrospective observational study.
Objective. To compare the usefulness of radioisotope cisternography (RIC) and computed tomography myelography (CTM) for the detection of cerebrospinal fluid (CSF) leakage in spontaneous intracranial hypotension (SIH).
Summary of Background Data. CSF leakage sites have been generally identified by RIC in patients with SIH. Although a number of reports have recently indicated the usefulness of CTM, whether RIC or CTM more reliably detects leakage sites has not been decided because the 2 tests have not been directly compared.
Methods. Both RIC and CTM were performed, and the findings were compared in 12 patients with SIH strictly meeting the second edition of the International Classification of Headache Disorders diagnostic criteria.
Results. On RIC, the detection rate of leakage including indirect signs, an early vesicular radioisotope (RI) accumulation and delayed ascent of the RI to the cerebral convexity, was observed in 100%, but that of the direct sign, paraspinal RI accumulation, was in 8 patients (67%). On CTM, the epidural collection of intraspinally administered contrast medium was demonstrated in all patients (100%), and the collection site was located in the cervical and thoracic vertebral regions in most cases. When RIC and CTM findings were collated, paraspinal accumulation in the cervical and thoracic regions on RIC corresponded to the entire or a part of the findings on CTM. In contrast, in 4 of 5 patients with paraspinal accumulation in the lumbosacral region, epidural collection was not noted in this region on CTM.
Conclusion. In patients with SIH, epidural collection on CTM may more accurately demonstrate CSF leakage compared with paraspinal RI accumulation on RIC.

DOI： 10.1097/BRS.0b013e31822e606a

Visualizing Non-Gaussian Diffusion: Clinical Application of q-Space Imaging and Diffusional Kurtosis Imaging of the Brain and Spine Reviewed

小児脳幹被蓋部の分水嶺

堀沙恵香, 田岡俊昭, 越智朋子, 明石敏昭, 坂本雅彦, 和田敬, 吉川公彦, 内田優美子, 高橋幸博

日本医学放射線学会学術集会抄録集 Vol. 71回 page： S130 - S130 2012.2

Masaaki Hori, Issei Fukunaga, Yoshitaka Masutani, Toshiaki Taoka, Koji Kamagata, Yuriko Suzuki, Shigeki Aoki

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 11 ( 4 ) page： 221 - 233 2012

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE

Recently, non-Gaussian diffusion-weighted imaging (DWI) techniques, including q-space imaging (QSI) and diffusional kurtosis imaging (DKI), have emerged as advanced methods to evaluate tissue microstructure in vivo using water diffusion. QSI and DKI have shown promising results in clinical applications, such as in the evaluation of brain tumors (e.g., grading gliomas), degenerative diseases (e.g., specific diagnosis of Parkinson disease), demyelinating diseases (e.g., assessment of normal-appearing tissue of multiple sclerosis), and cerebrovascular diseases (e.g., assessment of the microstructural environment of fresh infarctions). Representative metrics in clinical use are the full width at half maximum, also known as the mean displacement of the probability density function curve, which is derived from QSI, and diffusional kurtosis, which is derived from DKI. These new metrics may provide information on tissue structure in addition to that provided by conventional Gaussian DWI investigations that use the apparent diffusion coefficient and fractional anisotropy, recognized indices for evaluating disease and normal development in the brain and spine. In some clinical situations, sensitivity for detecting pathological conditions is higher using QSI and DKI than conventional DWI and diffusion tensor imaging (DTI) because DWI and DTI calculations are based on the assumption that water molecules follow a Gaussian distribution, whereas hindrance of the distribution of water molecules by complex and restricted structures in actual neural tissues produces distributions that are far from Gaussian. We review the technical aspects and clinical applications of QSI and DKI, focusing on clinical use and in vivo studies and highlighting differences from conventional diffusional metrics.

DOI： 10.2463/mrms.11.221

"DWI-SWI" Mismatch May Represent an Acute Ischemic Penumbra with Misery Perfusion Reviewed

Masayuki Fujioka, Masato Takahashi, Yusuke Tada, Hideki Asai, Asami Iwamura, Shingo Ito, Tomoo Watanabe, Yasuyuki Kawai, Tadahiko Seki, Hidetada Fukushima, Yasuyuki Urizono, Michiaki Hata, Toshiaki Akashi, Toshiaki Taoka, Kazuo Okuchi

CEREBROVASCULAR DISEASES Vol. 34 page： 79 - 79 2012

Diffusion Kurtosis Image of the Cerebral Infarction: Increased Axial Diffusion Kurtosis Reviewed

Toshiaki Taoka, Masayuki Fujioka, Masahiko Sakamoto, Toshiaki Akashi, Toshiteru Miyasaka, Tomoko Ochi, Saeke Hori, Takeshi Wada, Masato Uchikoshi, Kimihiko Kichikawa

CEREBROVASCULAR DISEASES Vol. 34 page： 81 - 81 2012

Global Brain Ischemia-Reperfusion Induces Striatal T1-Hyperintensity of Neuronal Death without Microbleeds in Human Brains: SWI Study on Cardiac Arrest Survivors Reviewed

Masayuki Fujioka, Keisuke Tsuruta, Asami Iwamura, Tomoo Watanabe, Hidetada Fukushima, Yasuyuki Urizono, Michiaki Hata, Masahiko Sakamoto, Toshiaki Taoka, Kazuo Okuchi

CEREBROVASCULAR DISEASES Vol. 34 page： 60 - 60 2012

DWMRI Study Reveals Late-Onset Cytotoxic Edema in the Pulvinar and Medial Nuclei of Thalami in Human Brains after Hypoglycemic Injury: Possible Remote Effects of Axonal and Transsynaptic Mechanism Reviewed

Masayuki Fujioka, Shingo Ito, Yusuke Tada, Asami Iwamura, Yasuyuki Kawai, Tadahiko Seki, Yasuyuki Urizono, Satoshi Suzuki, Yasuhide Kitazawa, Michiaki Hata, Toshiaki Taoka, Kazuo Okuchi

CEREBROVASCULAR DISEASES Vol. 34 page： 43 - 43 2012

The Use of Susceptibility-Weighted Imaging as an Indicator of Retrograde Leptomeningeal Venous Drainage with Dural Arteriovenous Fistula Reviewed

Ichiro Nakagawa, Fumihiko Nishimura, Yasuo Hironaka, Shuichi Yamada, Yasushi Motoyama, Young-Su Park, Toshiaki Taoka, Takeshi Wada, Hiroyuki Nakagawa, Kimihiko Kichikawa, Hiroyuki Nakase

CEREBROVASCULAR DISEASES Vol. 34 page： 42 - 43 2012

Discrepancy in T <inf>1</inf> and T <inf>2</inf> shortening of the globus pallidus in hepatic insufficiency: Evaluation by susceptibility-weighted imaging

Ochi T., Taoka T., Akashi T., Sakamoto M., Miyasaka T., Wada T., Nakagawa H., Takehana K., Tatsuno K., Kichikawa K.

Magnetic Resonance in Medical Sciences Vol. 10 ( 2 ) page： 79 - 83 2011.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Magnetic Resonance in Medical Sciences

Purpose: We assessed the signal of the globus pallidus (GP) in cases of hepatic in-sufficiency, especially to evaluate the degree of discrepancy in paramagnetic effects on shortening of T 1 and T 2* using susceptibility-weighted images (SWI). Materials and Methods: Seven patients with hepatic insufficiency underwent magnetic resonance (MR) examinations that included T 1-weighted images (T 1WI), T 2-weighted images (T 2WI), and SWI on a 1.5-tesla MR imager, and we compared their results to those of controls. On T 1WI and T 2WI, we measured signal intensity in the GP and posterior segment of the putamen (Put) to obtain a signal ratio (GP/Put ratio), and on SWI, we classified signal intensity into 4 grades: A, higher than the cortex; B, lower than the cortex and higher than the cerebrospinal fluid (CSF); C, lower than the CSF and higher than the red nucleus; and D, lower than the red nucleus. Results: In the 7 patients with hepatic insufficiency, the mean GP/Put ratio was significantly higher on T 1WI and T 2WI than those values in controls. On SWI, we classified 2 cases each as Grade A, Grade B, and Grade C, and one as Grade D. Although the signal of the GP was elevated on T 1WI, there was no decrease in signal on T 2WI. On SWI, we obtained no low signal intensity. Conclusion: In patients with hepatic insufficiency, the globus pallidus did not show low signal intensity on either T 2WI or SWI. Hyperintensity of the GP on T 1WI without hypoin-tensity on T 2WI, or even SWI, suggests a discrepancy between paramagnetic effect on T 1 and T 2 shortening that reflects the accumulation of manganese and the presence of hepatic insufficiency.

DOI： 10.2463/mrms.10.79

Adjunctive techniqueを用いた脳動脈瘤の瘤内塞栓

Tumefactive demyelinating disease(≧30mm)の神経放射線学的およびウイルス学的検討

桐山敬生, 形岡博史, 田岡俊昭, 殿村恭代, 守川公美, 川原誠, 杉江和馬, 降矢芳子, 吉川公彦, 上野聡

臨床神経学 Vol. 51 ( 12 ) page： 1221 - 1221 2011.12

中川裕之, 宮坂俊輝, 明珍薫, 和田敬, 坂本雅彦, 高山勝年, 田岡俊昭, 吉川公彦, 中川一郎, 内山佳知

JNET: Journal of Neuroendovascular Therapy Vol. 5 ( 4 ) page： 253 - 253 2011.11

FilterWire EZを用いた頸動脈ステント留置術初期治療成績

和田敬, 高山勝年, 中川裕之, 宮坂俊輝, 明珍薫, 坂本雅彦, 田岡俊昭, 中川一郎, 黒川紳一郎, 中瀬裕之, 吉川公彦

JNET: Journal of Neuroendovascular Therapy Vol. 5 ( 4 ) page： 257 - 257 2011.11

頭蓋内静脈逆流を伴う硬膜動静脈瘻におけるSusceptibility Weighted Imagingの有用性

中川一郎, 和田敬, 中川裕之, 弘中康雄, 本山靖, 朴永銖, 田岡俊昭, 吉川公彦, 中瀬裕之

JNET: Journal of Neuroendovascular Therapy Vol. 5 ( 4 ) page： 270 - 270 2011.11

Asymmetry, sex differences and age-related changes in the white matter in the healthy elderly: A tract-based study

Soichiro Kitamura, Masayuki Morikawa, Kuniaki Kiuchi, Toshiaki Taoka, Masami Fukusumi, Kimihiko Kichikawa, Toshifumi Kishimoto

BMC Research Notes Vol. 4 ( 1 ) page： 378 2011.10

Language：English Publishing type：Research paper (scientific journal) Publisher：BioMed Central

Background: Hemispherical asymmetry, sex differences and age-related changes have been reported for the human brain. Meanwhile it was still unclear the presence of the asymmetry or sex differences in the human brain occurred whether as a normal development or as consequences of any pathological changes. The aim of this study was to investigate hemispherical asymmetry, sex differences and age-related changes by using a tract-based analysis in the nerve bundles. Methods. 40 healthy elderly subjects underwent magnetic resonance diffusion tensor imaging, and we calculated fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the major white matter bundles. Results: We identified hemispherical asymmetry in the ADC values for the cingulate fasciculus in the total subject set and in males, and a sex difference in the FA values for the right uncinate fasciculus. For age-related changes, we demonstrated a significant increase in ADC values with advancing age in the right cingulum, left temporal white matter, and a significant decrease in FA values in the right superior longitudinal fasciculus. Conclusion: In this study, we found hemispherical asymmetry, sex differences and age-related changes in particular regions of the white matter in the healthy elderly. Our results suggest considering these differences can be important in imaging studies. © 2010 Kitamura et al
licensee BioMed Central Ltd.

DOI： 10.1186/1756-0500-4-378

Elementary Knowledge for MRI Interpretation

二相性の経過を示した傍腫瘍性脳幹脳炎のMRI画像とRamussen脳炎のベンゾジアゼピン受容体脳画像

形岡博史, 桐山敬生, 小林恭代, 泉哲石, 真貝隆之, 田岡俊昭, 上野聡

NEUROINFECTION Vol. 16 ( 2 ) page： 158 - 158 2011.10

TAOKA Toshiaki

Vol. 33 ( 2 ) page： 77 - 82 2011.9

Usefulness of Contrast-Enhanced Magnetic Resonance Angiography for Follow-Up of Coil Embolization With the Enterprise Stent for Cerebral Aneurysms Reviewed

Katsutoshi Takayama, Toshiaki Taoka, Hiroyuki Nakagawa, Kaoru Myouchin, Takeshi Wada, Masahiko Sakamoto, Akio Fukusumi, Satoru Iwasaki, Shinichiro Kurokawa, Kimihiko Kichikawa

JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Vol. 35 ( 5 ) page： 568 - 572 2011.9

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Objective: The aim of this study was to determine the feasibility and usefulness of contrast-enhanced magnetic resonance angiography (CE-MRA) and 3-dimensional (3D) time-of-flight (TOF) MRA for follow-up of intracranial aneurysms treated using the Enterprise stent.
Methods: Five aneurysm cases using the Enterprise stent were prospectively analyzed and were followed up with CE-MRA, 3D TOF MRA, and digital subtraction angiography (DSA). Depictions of parent artery lumen and the aneurysm neck with 3D TOF MRA and CE-MRA were compared with those of DSA.
Results: In all cases, on 3D TOF MRA, it was difficult to evaluate the parent artery lumen and aneurysm neck owing to the significant artifacts from the stent. Contrast-enhanced MRA sufficiently demonstrated parent artery lumen and aneurysm neck distinctly and as clear as DSA did in all cases.
Conclusions: For follow-up after coiling with an Enterprise stent, CE-MRA may be necessary to avoid susceptibility artifacts caused by the stent.

DOI： 10.1097/RCT.0b013e31822bd498

White matter changes in dementia with Lewy bodies and Alzheimer's disease: A tractography-based study

Kuniaki Kiuchi, Masayuki Morikawa, Toshiaki Taoka, Soichiro Kitamura, Tomohisa Nagashima, Manabu Makinodan, Keiju Nakagawa, Masami Fukusumi, Katsumi Ikeshita, Makoto Inoue, Kimihiko Kichikawa, Toshifumi Kishimoto

JOURNAL OF PSYCHIATRIC RESEARCH Vol. 45 ( 8 ) page： 1095 - 100 2011.8

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

Dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) are different types of dementia. However, their clinical symptoms partially overlap and differential diagnosis is occasionally difficult. There is need for additional diagnostic criteria to reliably differentiate between these two conditions. Meanwhile, several imaging studies have showed inconsistent results between DLB and AD. The aim of this study was to use a tractography-based analysis to elucidate white matter alterations in subjects with DLB compared to those with AD and to controls. An understanding of the white matter connectivity differences between AD, DLB and controls will be helpful for differential diagnosis and an understanding of the pathophysiology. Twenty-six subjects with DLB, 26 with AD and 26 controls underwent magnetic resonance diffusion tensor imaging and neuropsychological assessment. Diffusion tensors were computed and fiber-tract maps were created using "dTV II" software. We measured mean fractional anisotropy (FA) values along the uncinate fasciculus (UNC), the inferior occipitofrontal fasciculus (IOFF) and the inferior longitudinal fasciculus (ILF). Both subjects with DLB and AD had lower FA values for the bilateral UNC than controls. Subjects with DLB exhibited significantly lower FA values on both sides of the IOFF and the left side of the ILF than those of controls. Although there were no significant differences between subjects with DLB and AD for any measurements, those with DLB exhibited lower FA values especially in visual-related white matter. These different changes in white matter tracts among groups could be helpful for differential diagnosis and an understanding of the pathophysiology. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jpsychires.2011.01.011

Prediction of periprocedual ischemic complication in carotid artery stenting with filter embolic protection device by using magnetic resonance (MR) plaque imaging Reviewed

K. Kichikawa, K. Takayama, H. Nakagawa, K. Miyouchinn, T. Taoka, M. Sakamoto, T. Wada, S. Kurokawa

JOURNAL OF THROMBOSIS AND HAEMOSTASIS Vol. 9 page： 497 - 498 2011.7

Transient Hyperintensity in the Subthalamic Nucleus and Globus Pallidus of Newborns on T1-Weighted Images

T. Taoka, N. Aida, T. Ochi, Y. Takahashi, T. Akashi, T. Miyasaka, A. Iwamura, M. Sakamoto, K. Kichikawa

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 32 ( 6 ) page： 1130 - 7 2011.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: In the brains of newborns, changes in signal intensity in most structures can be explained by the development of myelination. However, there are some structures for which signal intensity changes cannot be accounted for by myelination alone. We examined the STN and globus pallidus signal intensities and tried to determine whether a relationship exists between the signal intensity and the postnatal age or the gestational age at the examination.
MATERIALS AND METHODS: We examined T1WI and T2WI obtained from 79 neonates who showed normal development at their 2-year follow-up examinations. We performed both qualitative and quantitative (signal intensity ratio to the thalamus) evaluation of the STN and globus pallidus signals, and we examined the correlation between signal intensity changes and the age of neonates.
RESULTS: With increasing postnatal age at examination, the high signal intensity on the T1WI for both STN and globus pallidus diminished. Although the disappearance of this hyperintensity was well correlated with the postnatal age at examination for both the qualitative and quantitative studies, there was no correlation with gestational age at examination. For the T2WI, there was no correlation with either the postnatal age or the gestational age at examination.
CONCLUSIONS: Signal intensity on T1WI in the STN and globus pallidus is not related to the gestational age at examination; instead, signal intensities on T1WI seem to be more dependent upon the postnatal age at examination.

DOI： 10.3174/ajnr.A2451

Characteristic Neuroimaging in Patients with Tumefactive Demyelinating Lesions Exceeding 30 mm

Takao Kiriyama, Hiroshi Kataoka, Toshiaki Taoka, Yasuyo Tonomura, Mari Terashima, Masami Morikawa, Emi Tanizawa, Makoto Kawahara, Yoshiko Furiya, Kazuma Sugie, Kimihiko Kichikawa, Satoshi Ueno

JOURNAL OF NEUROIMAGING Vol. 21 ( 2 ) page： e69 - 77 2011.4

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

BACKGROUND AND PURPOSE
Features of tumefactive demyelinating lesion (TDL) on magnetic resonance imaging (MRI) can facilitate the differential diagnosis of TDL and neoplastic lesions, but vary considerably among patients. The larger TDL grows, the more difficult it becomes to differentiate TDL from neoplastic lesions. The purpose of this study was to elucidate typical MRI features in 12 patients with large TDL (> 30 mm in diameter).
METHODS
We identified 12 patients with large TDL (six men, six women; age range 17-64 years, median age 27 years) and studied the clinical histories and the results of laboratory and various radiological studies in these patients. All cases of clinically definite multiple sclerosis were diagnosed in accordance with McDonald's revised criteria.
RESULTS
Common MRI features of large TDLs included variable degrees of mass effect (71%) and edema (100%), a T2 hypointense rim (79%), venular enhancement (57%), and peripheral restriction on diffusion-weighted images (50%). Ring enhancement (38%), open-ring enhancement (31%), or decreased N-acetylaspartate ratios on magnetic resonance spectroscopy (22%) were less frequently observed. Brain angiography demonstrated venous dilatations on and around the TDL.
CONCLUSIONS
The diagnosis of large TDL is challenging. Our findings suggest that multiple venous dilatations on and around TDLs on angiography can facilitate diagnosis.

DOI： 10.1111/j.1552-6569.2010.00502.x

Initial experience of carotid artery stenting using the Carotid WALLSTENT and FilterWire EZ in Japan

Katsutoshi Takayama, Toshiaki Taoka, Hiroyuki Nakagawa, Kaoru Myouchin, Takeshi Wada, Toshiteru Miyasaka, Masahiko Sakamoto, Akio Fukusumi, Satoru Iwasaki, Ryota Kimura, Shinichiro Kurokawa, Kimihiko Kichikawa

JAPANESE JOURNAL OF RADIOLOGY Vol. 29 ( 1 ) page： 51 - 58 2011.1

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The Carotid WALLSTENT (CWS) and Filter-Wire EZ (FWEZ) embolic protection devices for use in carotid arterial stenting (CAS) were newly approved for national health insurance coverage in Japan in April 2010. This article describes our initial experience of CAS using the CWS and FWEZ.
A group of 14 patients (12 men, 2 women; mean age 70.1 years, range 59-83 years) with 15 carotid artery stenoses at high risk for carotid endarterectomy were treated by CAS using the CWS and FWEZ. Of these stenoses, 5 were symptomatic with a parts per thousand yen50% stenosis of the common or internal carotid artery (ICA), and 10 were asymptomatic with a parts per thousand yen80% stenosis. The rates of technical success, ICA flow impairment during filter protection, periprocedural ischemic stroke, 30-day major adverse events (MAEs) (stroke, death, myocardial infarction), and development of new ischemic lesions on diffusion-weighted imaging (DWI) were assessed.
CAS was successful in all cases. There was no ICA flow impairment, periprocedural ischemic stroke, or MAEs. DWI showed new ipsilateral ischemic lesions in only one patient (6.7%).
Our initial clinical experience using the CWS and FEWZ for CAS was generally excellent, and the incidence of postprocedural ischemic lesions was low.

DOI： 10.1007/s11604-010-0518-x

Serial Neuroimaging in Tolosa-Hunt Syndrome with Acute Bilateral Complete Ophthalmoplegia

Kazuma Sugie, Masami Morikawa, Toshiaki Taoka, Makito Hirano, Satoshi Ueno

JOURNAL OF NEUROIMAGING Vol. 21 ( 1 ) page： 79 - 82 2011.1

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL PUBLISHING, INC

Tolosa-Hunt syndrome (THS) is a very rare, relapsing, and remitting painful ophthalmoplegia caused by nonspecific granulomatous inflammation in the cavernous sinus. To our knowledge, bilateral complete, simultaneous palsies of all 3 cranial nerves associated with extraocular movement have not been reported. We describe the first such patient with bilateral THS that responded quickly to corticosteroid therapy. A 54-year-old man presented with a periorbital and frontal headache with acute bilateral severe blepharoptosis and fixed eyes, which dramatically responded to corticosteroid therapy. He had diabetes mellitus type II. Brain MRI showed granulomatous inflammation in both cavernous sinuses and thickening of the surrounding dura mater of the cranial base, suggesting the coexistence of focal hypertrophic cranial pachymeningitis. Our experience indicates that steroid therapy with strict control of blood sugar should be considered in patients with THS complicated by diabetes. MRI is a valuable tool for serially monitoring the response of lesions to treatment in THS.

DOI： 10.1111/j.1552-6569.2009.00381.x

Hyperintense Dentate Nucleus on Unenhanced T1-weighted MR Images Is Associated with a History of Brain Irradiation Reviewed International journal

Seiko Kasahara, Yukio Miki, Mitsunori Kanagaki, Akira Yamamoto, Nobuyuki Mori, Takeshi Sawada, Toshiaki Taoka, Tomohisa Okada, Kaori Togashi

RADIOLOGY Vol. 258 ( 1 ) page： 222 - 228 2011.1

Language：English Publishing type：Research paper (scientific journal) Publisher：RADIOLOGICAL SOC NORTH AMERICA

Purpose: To assess the frequency of hyperintensity in the dentate nucleus on T1-weighted magnetic resonance (MR) images and to establish correlations between such hyperintensity and clinical factors, including a history of brain irradiation.
Materials and Methods: This study was approved by the institutional review board, and each patient provided written informed consent. Three hundred sixty-two patients (164 men, 198 women; mean age, 62 years) were evaluated. Unenhanced T1-weighted MR images were obtained by using a spin-echo sequence at 3.0 T. Two neuroradiologists, who were blinded to clinical data, independently evaluated the signal intensity of the dentate nucleus compared with the signal intensity of the central white matter of the cerebellum by using a four-point graded response scale (grade 4 indicated prominent hyperintensity; grade 3, faint hyperintensity; grade 2, isointensity; and grade 1, hypointensity). Backward stepwise regression analysis was used to evaluate the relationship between signal intensity grades and the following clinical factors: sex, age, the interaction between age and sex, hypertension, dyslipidemia, diabetes mellitus, liver dysfunction, brain infarction, brain tumor, spinocerebellar degeneration, multiple sclerosis, a history of chemotherapy, and a history of brain irradiation.
Results: T1-hyperintense dentate nuclei were present in 41 (11%) of the 362 patients. Of these 41 patients, 31 (76%) had a history of brain irradiation. Signal intensity grade of the dentate nucleus on T1-weighted MR images correlated significantly with a history of brain irradiation (P < .001) but no other clinical factor.
Conclusion: A hyperintense dentate nucleus may be seen on unenhanced T1-weighted MR images in some patients and may be associated with a history of brain irradiation. (C) RSNA, 2010

DOI： 10.1148/radiol.10100508

Discrepancy in T-1 and T-2 Shortening of the Globus Pallidus in Hepatic Insufficiency: Evaluation by Susceptibility-weighted Imaging

Tomoko Ochi, Toshiaki Taoka, Toshiaki Akashi, Masahiko Sakamoto, Toshiteru Miyasaka, Takeshi Wada, Hiroyuki Nakagawa, Keiichi Takehana, Kentaro Tatsuno, Kimihiko Kichikawa

MAGNETIC RESONANCE IN MEDICAL SCIENCES Vol. 10 ( 2 ) page： 79 - 83 2011

Language：English Publishing type：Research paper (scientific journal) Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE

Purpose: We assessed the signal of the globus pallidus (GP) in cases of hepatic insufficiency, especially to evaluate the degree of discrepancy in paramagnetic effects on shortening of T-1 and T-2* using susceptibility-weighted images (SWI).
Materials and Methods: Seven patients with hepatic insufficiency underwent magnetic resonance (MR) examinations that included T-1-weighted images (T1WI), T-2-weighted images (T2WI), and SWI on a 1.5-tesla MR imager, and we compared their results to those of controls. On T1WI and T2WI, we measured signal intensity in the GP and posterior segment of the putamen (Put) to obtain a signal ratio (GP/Put ratio), and on SWI, we classified signal intensity into 4 grades: A, higher than the cortex; B, lower than the cortex and higher than the cerebrospinal fluid (CSF); C, lower than the CSF and higher than the red nucleus; and D, lower than the red nucleus.
Results: In the 7 patients with hepatic insufficiency, the mean GP/Put ratio was significantly higher on T1WI and T2WI than those values in controls. On SWI, we classified 2 cases each as Grade A, Grade B, and Grade C, and one as Grade D. Although the signal of the GP was elevated on T1WI, there was no decrease in signal on T2WI. On SWI, we obtained no low signal intensity.
Conclusion: In patients with hepatic insufficiency, the globus pallidus did not show low signal intensity on either T2WI or SWI. Hyperintensity of the GP on T1WI without hypointensity on T2WI, or even SWI, suggests a discrepancy between paramagnetic effect on T-1 and T-2 shortening that reflects the accumulation of manganese and the presence of hepatic insufficiency.

DOI： 10.2463/mrms.10.79

Discrepancy in T1 and T2 Shortening of the Globus Pallidus in Hepatic Insufficiency: Evaluation by Susceptibility-weighted Imaging

OCHI Tomoko, TAOKA Toshiaki, AKASHI Toshiaki, SAKAMOTO Masahiko, MIYASAKA Toshiteru, WADA Takeshi, NAKAGAWA Hiroyuki, TAKEHANA Keiichi, TATSUNO Kentaro, KICHIKAWA Kimihiko

Magnetic Resonance in Medical Sciences Vol. 10 ( 2 ) page： 79 - 83 2011

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

Purpose: We assessed the signal of the globus pallidus (GP) in cases of hepatic insufficiency, especially to evaluate the degree of discrepancy in paramagnetic effects on shortening of T1 and T2* using susceptibility-weighted images (SWI). Materials and Methods: Seven patients with hepatic insufficiency underwent magnetic resonance (MR) examinations that included T1-weighted images (T1WI), T2-weighted images (T2WI), and SWI on a 1.5-tesla MR imager, and we compared their results to those of controls. On T1WI and T2WI, we measured signal intensity in the GP and posterior segment of the putamen (Put) to obtain a signal ratio (GP/Put ratio), and on SWI, we classified signal intensity into 4 grades: A, higher than the cortex; B, lower than the cortex and higher than the cerebrospinal fluid (CSF); C, lower than the CSF and higher than the red nucleus; and D, lower than the red nucleus. Results: In the 7 patients with hepatic insufficiency, the mean GP/Put ratio was significantly higher on T1WI and T2WI than those values in controls. On SWI, we classified 2 cases each as Grade A, Grade B, and Grade C, and one as Grade D. Although the signal of the GP was elevated on T1WI, there was no decrease in signal on T2WI. On SWI, we obtained no low signal intensity. Conclusion: In patients with hepatic insufficiency, the globus pallidus did not show low signal intensity on either T2WI or SWI. Hyperintensity of the GP on T1WI without hypointensity on T2WI, or even SWI, suggests a discrepancy between paramagnetic effect on T1 and T2 shortening that reflects the accumulation of manganese and the presence of hepatic insufficiency.

DOI： 10.2463/mrms.10.79

White matter changes in dementia with Lewy bodies and Alzheimer's disease: A tractgraphy-based study Reviewed

Soichiro Kitamura, Kuniaki Kiuchi, Masayuki Morikawa, Toshiaki Taoka, Tomohisa Nagashima, Kazuhiko Yamamuro, Hiroki Yoshino, Tomohiko Takeda, Miyuki Sadamatsu, Kimi-hiko Kichikawa, Toshifumi Kishimoto

NEUROSCIENCE RESEARCH Vol. 71 page： E289 - E289 2011

Reduced white matter integrity in attention-deficit hyperactivity disorder Whole-brain voxel-wise investigation Reviewed

M. Inoue, K. Kiuchi, T. Nagashima, T. I. Taoka, K. Kichikawa, T. Kishimoto

INTERNATIONAL JOURNAL OF DEVELOPMENTAL NEUROSCIENCE Vol. 28 ( 8 ) page： 712 - 712 2010.12

Brain surface motion imaging to predict adhesions between meningiomas and the brain surface International journal

Toshiaki Taoka, Syuichi Yamada, Yuya Yamatani, Toshiaki Akashi, Toshiteru Miyasaka, Tomoko Emura, Hiroyuki Nakase, Kimihiko Kichikawa

NEURORADIOLOGY Vol. 52 ( 11 ) page： 1003 - 10 2010.11

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

"Brain surface motion imaging" (BSMI) is the subtraction of pulse-gated, 3D, heavily T2-weighted image of two different phases of cerebrospinal fluid (CSF) pulsation, which enables the assessment of the dynamics of brain surface pulsatile motion. The purpose of this study was to evaluate the feasibility of this imaging method for providing presurgical information about adhesions between meningiomas and the brain surface.
Eighteen cases with surgically resected meningioma in whom BSMI was presurgically obtained were studied. BSMI consisted of two sets of pulse-gated, 3D, heavily T2-weighted, fast spin echo scans. Images of the systolic phase and the diastolic phase were obtained, and subtraction was performed with 3D motion correction. We analyzed the presence of band-like texture surrounding the tumor and judged the degree of motion discrepancy as "total," "partial," or "none." The correlation between BSMI and surgical findings was evaluated. For cases with partial adhesions, agreements in the locations of the adhesions were also evaluated.
On presurgical BSMI, no motion discrepancy was seen in eight cases, partial in six cases, and total in four cases. These presurgical predictions about adhesions and surgical findings agreed in 13 cases (72.2%). The locations of adhesions agreed in five of six cases with partial adhesions.
In the current study, BSMI could predict brain and meningioma adhesions correctly in 72.2% of cases, and adhesion location could also be predicted. This imaging method appears to provide presurgical information about brain/meningioma adhesions.

DOI： 10.1007/s00234-010-0671-z

A patient with IgG4-related disease detected due to the presence of optic disc edema

Yukawa E., Nitta N., Taoka T., Morita K., Nishi T., Hara Y.

Folia Japonica de Ophthalmologica Clinica Vol. 3 ( 11 ) page： 1207 - 1210 2010.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Folia Japonica de Ophthalmologica Clinica

We encountered a patient who showed optic disc edema and was finally diagnosed with IgG4-related disease. An 81-year-old male with cataract was referred to our department for surgery. At the time of the initial consultation, edema was observed in the bilateral optic discs. Brain magnetic resonance imaging revealed hypophysitis and hypertrophic cranial pachymeningitis. Close examination of the entire body showed interstitial nephritis and a lung lesion. In addition, since the IgG4 level was high, a final diagnosis of IgG4-related disease was made. In recent years, IgG4-related disease has attracted attention as a systemic disease. In the future, when optic disc edema is observed, hypertrophic cranial pachymeningitis and IgG4-related disease should also be taken into consideration, and close examination of the entire body in cooperation with other departments may also be necessary.

FilterWireEZ保護下でのPreciseおよびWallstentを用いた再CASの一例

中川裕之, 宮坂俊輝, 和田敬, 坂本雅彦, 田岡俊昭, 吉川公彦, 中川一郎, 明珍薫, 高山勝年

JNET: Journal of Neuroendovascular Therapy Vol. 4 ( 4 ) page： 291 - 291 2010.11

内頸動脈起始部高度狭窄に対するステント留置術中に総頸動脈起始部狭窄を発見し、血管拡張術を併用して治療に成功した1例

和田敬, 高山勝年, 中川裕之, 宮坂俊輝, 明珍薫, 坂本雅彦, 田岡俊昭, 吉川公彦, 黒川紳一郎

JNET: Journal of Neuroendovascular Therapy Vol. 4 ( 4 ) page： 367 - 367 2010.11

Biphasic paraneoplastic brainstem encephalitis associated with anti-Ri antibody

Kin Tesseki, Hiroshi Kataoka, Mari Terashima, Makoto Kawahara, Toshiaki Taoka, Keiko Tanaka, Satoshi Ueno

JOURNAL OF NEURO-ONCOLOGY Vol. 100 ( 1 ) page： 141 - 3 2010.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Brainstem encephalitis is not a classic paraneoplastic syndrome and usually involves monophasic neurological deterioration and has negative magnetic resonance imaging (MRI) findings. We describe a patient with brainstem encephalitis who had elevated anti-Ri antibody levels and double-step neurological deterioration associated with different abnormal lesions on MRI. Immunosuppression with steroids and intravenous immune globulin combined with aggressive treatment of the tumor successfully led to the resolution of brainstem symptoms and MRI lesions. In patients with unusual signs and symptoms of paraneoplastic encephalitis mimicking multiple sclerosis, onconeural antibody studies are recommended.

DOI： 10.1007/s11060-010-0135-7

Anatomical Evaluation of the Dural Sinuses in the Region of the Torcular Herophili Using Three Dimensional CT Venography Reviewed International journal

Akio Fukusumi, Toshio Okudera, Shoki Takahashi, Toshiaki Taoka, Masahiko Sakamoto, Hiroyuki Nakagawa, Katsutoshi Takayama, Kimihiko Kichikawa, Satoru Iwasaki

ACADEMIC RADIOLOGY Vol. 17 ( 9 ) page： 1103 - 1111 2010.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Rationale and Objectives: The torcular herophili, or "confluence of the sinuses," shows various configurations with other venous sinuses, as revealed by angiography. The aims of this study were to evaluate anatomic variations of this confluence and to assess their clinical relevance using three-dimensional (3D) computed tomographic (CT) venography. Materials and
Methods: The torcular herophili and its relevant venous sinuses were analyzed using 3D CT venography in 120 adults, consisting of 76 patients who were proven to have aneurysms and 44 patients who were proven to have no vascular malformations or aneurysms after the examinations. Three-dimensional CT venography was performed following the arterial phase of 3D CT angiography without any additional injection of contrast material. Three-dimensional volume-rendered venous images were reconstructed on a workstation and reviewed.
Results: The superior sagittal sinus (SSS) drained into the transverse sinus (TS) in four patterns: the SSS reached the centrally located confluence, where it divided into the bilateral TS (20.0%); the SSS was prematurely duplicated into the right and left limbs and drained into the same side TS (26.7%); the SSS drained exclusively into the right IS (44.2%); or the SSS drained exclusively into the left TS (9.2%). The draining pattern of the straight sinus was also classified into four types. The right TS was larger than the left TS. The right TS were higher compared to the left TS. Persistent occipital sinuses were recognized in 57.5% of the subjects. Finally, persistent falcial sinuses were seen in 2.5% of the subjects. A septum in the SSS and complicated venous channels in the confluence were each seen in only one case.
Conclusion: Three-dimensional CT venography is useful as a noninvasive method to evaluate the confluence and its relevant dural sinuses and can provide useful information for surgical intervention.

DOI： 10.1016/j.acra.2010.04.020

Hepatocellular carcinoma of the iliac bone with unknown primary International journal

Junko Takahama, Toshiaki Taoka, Nagaaki Marugami, Hiroshi Anai, Satoru Kitano, Kimihiko Kichikawa, Akitaka Nonomura

SKELETAL RADIOLOGY Vol. 39 ( 7 ) page： 721 - 4 2010.7

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

We report a case of hepatocellular carcinoma of the iliac bone in which the primary tumor was not detected. No malignant primary lesions such as hepatocellular carcinoma or hepatoid carcinoma were detected at the time or during 10 years' follow-up. In this case, transcatheter arterial chemo-embolization and radiation therapy resulted in complete regression of the iliac bone tumor and in long-term survival. We focus in particular on the clinical, histological, and therapeutic aspects of the presented case, as well as the imaging and diagnostic aspects.

DOI： 10.1007/s00256-010-0891-7

Artery-to-Artery Embolism with a Mobile Mural Thrombus Due to Rotational Vertebral Artery Occlusion

Kozue Saito, Makito Hirano, Toshiaki Taoka, Hiroyuki Nakagawa, Takanori Kitauchi, Emi Tanizawa, Koichi Yoshida, Yoshihiko Sakurai, Kentaro Tamura, Hiroyuki Nakase, Akira Yoshioka, Toshisuke Sakaki, Kimihiko Kichikawa, Satoshi Ueno

JOURNAL OF NEUROIMAGING Vol. 20 ( 3 ) page： 284 - 6 2010.7

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Rotational vertebral artery (VA) occlusion can cause ischemic strokes due to hemodynamic insufficiency and possibly artery-to-artery (A-to-A) embolism. The former is known as bow hunter's stroke. The latter has been proposed only from indirect evidence. We have described a 7-year-old boy with cerebral infarction associated with A-to-A embolism due to repetitive rotational VA occlusion. He had a mobile mural thrombus at the VA occlusion site on head rotation. Surgical treatment may effectively prevent recurrences.

DOI： 10.1111/j.1552-6569.2008.00309.x

Magnetic resonance plaque imaging to predict the occurrence of the slow-flow phenomenon in carotid artery stenting procedures

Masahiko Sakamoto, Toshiaki Taoka, Hiroyuki Nakagawa, Katsutoshi Takayama, Takeshi Wada, Kaoru Myouchin, Toshiaki Akashi, Toshiteru Miyasaka, Akio Fukusumi, Satoru Iwasaki, Kimihiko Kichikawa

NEURORADIOLOGY Vol. 52 ( 4 ) page： 275 - 83 2010.4

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a filter-type protection device.
Thirty-one carotid artery stenotic lesions in 30 patients (28 men and two women; mean age, 71.8 years) were evaluated by MR plaque imaging with black blood T1- and T2-weighted and time-of-flight sequences before CAS. Main plaque components were classified as vulnerable (intraplaque hemorrhage and lipid-rich/necrotic core) or stable (fibrous tissue and dense calcification) from the signal pattern. The plaque classification was statistically compared with the occurrence of slow-flow phenomenon.
The slow-flow phenomenon was observed in ten CAS procedures (five flow arrests and five flow reductions). Flow arrests consisted of four vulnerable and one stable plaque, and flow reductions consisted of four vulnerable and one stable plaque. The slow-flow phenomenon occurred significantly (P < 0.01) more frequently in patients with vulnerable plaque.
Vulnerable carotid plaques have a significantly higher risk of slow-flow phenomenon than stable plaques. The occurrence of the slow-flow phenomenon can be predicted by MR plaque imaging before CAS.

DOI： 10.1007/s00234-009-0623-7

Uncinate fasciculus-correlated cognition in Alzheimer's disease: a diffusion tensor imaging study by tractography

Masayuki Morikawa, Kuniaki Kiuchi, Toshiaki Taoka, Kiyoyuki Nagauchi, Kimihiko Kichikawa, Toshifumi Kishimoto

PSYCHOGERIATRICS Vol. 10 ( 1 ) page： 15 - 20 2010.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Background:
Neuroimaging studies show increased diffusivity and decreased anisotropy in Alzheimer's disease (AD) patients by diffusion tensor imaging (DTI). Previous reports have analyzed a correlation with cognitive function and DTI parameters, but their results are inconsistent. A reason for this might be a region of interest (ROI) method, used to calculate parameters for DTI, because this method has various usages of how to place a ROI and includes summations of values for various neuronal fiber tracts, resulting in contamination of unintended fibers. To improve the instability with ROI placement, a tractography-based method might be useful. Our coworker reported decreased fractional anisotropy (FA) and increased apparent diffusion coefficient (ADC) of uncinate fasciculus (UF) in patients with AD by tractography. To confirm whether DTI parameter values are related to severity of cognitive function in patients with AD, we measured mean diffusion anisotropy and diffusivity of coregistered voxels along the tracking lines (i.e. tract of interest) of UF.
Methods:
The subjects were 30 patients with probable AD (NINCDS-ADRDA criteria). Assessment of cognitive function was carried out according to the Mini-Mental State Examination (MMSE) and the Alzheimer's Disease Assessment Scale-cognitive component-Japanese version (ADAS-Jcog). A 1.5-T clinical magnetic resonance unit was used to obtain diffusion tensor images. Diffusion tensors were computed and fiber-tract maps were created using 'dTV II' DTI software developed by Masutani et al. We measured mean FA and ADC values along the bilateral UF.
Results:
FA values were positively correlated with MMSE score (r = 0.67) and were negatively correlated with ADAS-Jcog score (r = -0.62), while ADC values were negatively correlated with MMSE score (r = -0.58) and were positively correlated with ADAS-Jcog score (r = 0.59).
Conclusion:
FA and ADC values might reflect the severity of cognitive dysfunction. The tract-of-interest method might be a useful tool for objectively evaluating DTI parameters in AD.

DOI： 10.1111/j.1479-8301.2010.00312.x

Magnetic Resonance Angiography With Midsagittal Saturation for the Assessment of Blood Flow From Superficial Temporal Artery-to-Middle Cerebral Artery Bypass

Toshiaki Akashi, Toshiaki Taoka, Toshiteru Miyasaka, Kaoru Myochin, Masahiko Sakamoto, Katsutoshi Takayama, Hiroyuki Nakagawa, Kimihiko Kichikawa

JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Vol. 34 ( 1 ) page： 89 - 92 2010.1

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Objective: The purpose of this study was to evaluate the feasibility of magnetic resonance angiography (MRA) with rnidsagittal saturation for depiction Of Superficial temporal artery-to-middle cerebral artery bypass flow.
Methods: Eleven patients undergoing bypass surgery in 13 regions were examined by external carotid artery angiography (ECAG) and 3-dimensional time-of-flight MRA with saturation pulse applied to the midsagittal plane covering tire internal carotid arteries. We classified the extent of visualization of bypass flow into 4 types and examined the agreement of findings between them.
Results: The MRA revealed types of bypass flow in agreement with those observed on ECAG in 10 of the 13 regions. The M RA underestimated bypass flow in 2 regions, and overestimated it in 1 region.
Conclusions: The MRA with midsagittal saturation demonstrated bypass flow in agreement with ECAG in most cases. Application of MRA with midsagittal saturation permits noninvasive assessment of physiological flow from superficial temporal artery-to-middle cerebral artery bypass for a postoperative follow-up.

DOI： 10.1097/RCT.0b013e3181ac914e

Imaging and tissue characterization of atherosclerotic carotid plaque using MR imaging Reviewed

Juvenile Bow Hunter's Stroke without Hemodynamic Changes. Reviewed

Saito K, Hirano M, Taoka T, Nakagawa H, Kitauchi T, Ikeda M, Tanizawa E, Kichikawa K, Ueno S

Clinical medicine insights. Case reports Vol. 3 page： 1 - 4 2010.1

Brain structural change in polydipsic schizophrenia Reviewed

Nagashima T, Inoue M, Kitamura S, Kiuchi K, Kosaka J, Ikawa D, Takeda T, Kimoto S, Hirota N, Taoka T, Kichikawa K, Kishimoto T

Society for Neuroscience Abstract Viewer and Itinerary Planner Vol. 40 2010

Toshiaki Taoka

Neurovascular Imaging: MRI and Microangiography page： 319 - 343 2010

Language：English Publishing type：Part of collection (book) Publisher：Springer London

The carotid bifurcation is a frequent site for atheromatous diseases, and severe stenosis or occlusion of the bifurcation leads to hypoperfusion of the brain [5]. Progression of carotid artery disease relates closely to future cerebral or coronary infarction
stability of the carotid plaque and degree of carotid stenosis are important factors in disease development and assessment. Diagnosis of unstable plaque (vulnerable plaque) is important because its presence may lead to embolic diseases in the brain. Both the size and composition of plaque influence its stability [13]. Histological characteristics of unstable plaque include a large necrotic core that contains a large amount of cholesterol ester, intraplaque hemorrhage, and/or infiltration by inflammatory cells. Diagnosis of carotid plaque should be aimed at evaluating the degree of fibrosis, thrombosis, existence of lipid or calcification, and degree of stenosis or plaque thickness. In addition, the Rotterdam Study of more than 4,000 neurologically asymptomatic subjects aged 55 years or older associated carotid plaque with increased risk of stroke, irrespective of plaque location. Study results suggest that carotid plaque in such subjects is a marker of generalized atherosclerosis and a source of thrombotic emboli [20]. © 2011 Springer-Verlag London Limited.

DOI： 10.1007/978-1-84882-134-7_11

Juvenile bow hunter's stroke without hemodynamic changes

Juvenile Bow Hunter's Stroke without Hemodynamic Changes. Reviewed

Saito Kozue, Hirano Makito, Taoka Toshiaki, Nakagawa Hiroyuki, Kitauchi Takanori, Ikeda Masanori, Tanizawa Emi, Kichikawa Kimihiko, Ueno Satoshi

Clinical medicine insights. Case reports Vol. 3 page： 1 - 4 2010

Saito K., Hirano M., Taoka T., Nakagawa H., Kitauchi T., Ikeda M., Tanizawa E., Kichikawa K., Ueno S.

Clinical Medicine Insights: Case Reports Vol. 3 page： 1 - 4 2010

Language：English Publishing type：Research paper (scientific journal) Publisher：Clinical Medicine Insights: Case Reports

Bow hunter's stroke (BHS) is a cerebrovascular disease caused by occlusion of the vertebral artery (VA) on head rotation. BHS is generally associated with hemodynamic changes, often leading to vertebrobasilar insufficiency symptoms, such as vertigo and faintness. Although artery-to-artery embolism has also been proposed as an underlying mechanism, it remains controversial. This report documents a case of BHS without hemodynamic changes. We describe a 26-year-old male patient who had VA occlusion on head rotation and repetitive infarction of thalami. He had an anomalous bypass of the VA and therefore no symptomatic hemodynamic changes. Thus, non-hemodynamic BHS should be considered in juvenile patients with vertebrobasilar stroke. © the authors, publisher and licensee Libertas Academica Ltd.

DOI： 10.4137/ccrep.s3555

Carotid artery stenosis with intraluminal thrombus discovered during carotid artery stenting

Katsutoshi Takayama, Toshiaki Taoka, Hiroyuki Nakagawa, Toshiteru Miyasaka, Kaoru Myouchin, Takeshi Wada, Masahiko Sakamoto, Toshiaki Akashi, Kimihiko Kichikawa

JAPANESE JOURNAL OF RADIOLOGY Vol. 27 ( 9 ) page： 367 - 370 2009.11

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

A 77-year-old man presented with transient motor weakness of the left hand. Cerebral angiography showed 90% stenosis at the origin of the right internal carotid artery. Carotid artery stenting (CAS) was performed 3 weeks later, and a large intraluminal thrombus was found during the procedure. The blood around the thrombus was aspirated using an aspiration catheter under distal protection with a filter wire protection device, and CAS was successfully performed without complications. Although this patient was treated by CAS without complications, carotid stenosis associated with intraluminal thrombus-because it has a high risk of distal embolism-should be carefully diagnosed immediately before CAS.

DOI： 10.1007/s11604-009-0348-x

Superior clinical impact of FDG-PET compared to MRI for the follow-up of a patient with sacral lymphoma. Reviewed

Yamamoto Y, Taoka T, Nakamine H

Journal of clinical and experimental hematopathology : JCEH Vol. 49 ( 2 ) page： 109 - 115 2009.11

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Lymphoreticular Tissue Research

The assessment of residual tumors after treatment of malignant lymphoma (ML) is often difficult. Here we report a case of non-Hodgkin's lymphoma with a huge sacral tumor. After chemotherapy and following radiation therapy, a residual mass was detected on magnetic resonance imaging (MRI). However, a hypermetabolic lesion in the sacrum disappeared on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) and clinically the patient was considered to achieve complete remission. Seven months after the completion of radiation therapy, a new tumor-like lesion in the sacrum developed on MRI, but hypermetabolic lesions were not detected on 18F-FDG-PET. Recurrence of lymphoma was denied by open biopsy of the lesion. 18F-FDG-PET has been of widespread use not only for staging but for post-treatment assessment of ML. Although MRI is a standard imaging tool for the assessment of bone involvement of ML, there have been few reports documenting the results of comparative studies on the usefulness of 18F-FDG-PET and MRI for the evaluation of residual mass in bone involvement of ML. The present case suggests that 18F-FDG-PET is superior to MRI not only in the evaluation of a residual mass but in the judgment of recurrence after treatment of such patients. [J Clin Exp Hematopathol 49(2) : 109-115, 2009]

DOI： 10.3960/jslrt.49.109

CiNii Books

Other Link： http://search.jamas.or.jp/link/ui/2010112585

Prototype of Foot-Controlled Image-Scrolling Device for the Picture Archiving and Communication System Display Interface International journal

Toshiaki Taoka, Junko Takahama, Yuko Nishimoto, Sachiko Miura, Megumi Takewa, Yasushi Kubota, Kimihiko Kichikawa

JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Vol. 33 ( 6 ) page： 978 - 80 2009.11

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Our purpose was to produce a prototype of a foot-controlled image-scrolling device that will prevent work-related upper extremity complaints by radiologists. After foot-controlled image-scrolling devices were added to a picture archiving and communication system, 15 (83%) of 18 radiologists indicated that fatigue and pain in their upper extremities were diminished. Upon further production and implementation of this image-scrolling device in radiology clinics, the new interface may help to prevent work-related injuries in radiologists.

DOI： 10.1097/RCT.0b013e31819d98da

動眼神経麻痺で発症した内頸動脈後交通動脈分岐部動脈瘤に対してコイル塞栓術が有効であった1例

和田敬, 高山勝年, 中川裕之, 宮坂俊輝, 明珍薫, 坂本雅彦, 田岡俊昭, 吉川公彦, 中川一郎, 黒川紳一郎

JNET: Journal of Neuroendovascular Therapy Vol. 3 ( 4 ) page： 231 - 231 2009.11

Fractional Anisotropy-Threshold Dependence in Tract-Based Diffusion Tensor Analysis: Evaluation of the Uncinate Fasciculus in Alzheimer Disease Reviewed

T. Taoka, M. Morikawa, T. Akashi, T. Miyasaka, H. Nakagawa, K. Kiuchi, T. Kishimoto, K. Kichikawa

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 30 ( 9 ) page： 1700 - 1703 2009.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: Tract-based analysis can be used to investigate required tracts extracted from other fiber tracts. However, the fractional anisotropy (FA) threshold influences tractography analysis. The current study evaluated the influence of the FA threshold in measuring diffusion tensor parameters for tract-based analysis of the uncinate fasciculus in subjects with Alzheimer disease (AD).
MATERIALS AND METHODS: Subjects included 30 patients with AD and 10 healthy controls. We acquired tractographies of the uncinate fasciculus by using different FA thresholds. We measured mean FA and the apparent diffusion coefficient (ADC) along the uncinate fasciculus for different FA thresholds and evaluated the correlation between diffusion tensor parameters (FA, ADC) and the Mini-Mental State Examination (MMSE) scores.
RESULTS: The uncinate fasciculus showed lower mean FA and higher mean ADC values in cases with more severe AD. A higher FA threshold led to a lower mean ADC value and a higher mean FA value along the uncinate fasciculus, whereas the relative order of measured values according to the severity of AD was not influenced by the FA threshold. An FA threshold of 0.2 showed higher correlation between mean ADC values and MMSE scores. FA thresholds of 0.15 and 0.20 showed higher correlation between mean FA values and MMSE scores.
CONCLUSIONS: Appropriate selection of the FA threshold leads to higher correlation between diffusion tensor parameters and the severity of AD. For tract-based analysis of degenerative diseases such as AD, appropriate selection of the FA threshold for tractography is important.

DOI： 10.3174/ajnr.A1698

Abnormalities of the uncinate fasciculus and posterior cingulate fasciculus in mild cognitive impairment and early Alzheimer's disease: A diffusion tensor tractography study

Kuniaki Kiuchi, Masayuki Morikawa, Toshiaki Taoka, Tomohisa Nagashima, Takahira Yamauchi, Manabu Makinodan, Kazunobu Norimoto, Kazumichi Hashimoto, Jun Kosaka, Yuichiro Inoue, Makoto Inoue, Kimihiko Kichikawa, Toshifumi Kishimoto

BRAIN RESEARCH Vol. 1287 page： 184 - 91 2009.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Mild cognitive impairment (MCI) is considered the transitional stage between normal cognition and dementia. The aim of this study was to use tractography based analysis to elucidate alterations in subjects with MCI compared with subjects with early Alzheimer's disease (AD) and controls. Seventeen subjects with early AD, 16 with MCI and 16 controls underwent magnetic resonance diffusion tensor imaging (DTI) and neuropsychological assessment. Diffusion tensor tractographies were computed and fiber-tract maps were generated using "dTV II" DTI software. We measured mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the uncinate fasciculus (UNC), posterior cingulate fasciculus (PCF) and corticospinal tract (CST). There were statistically significant differences in the FA and ADC values of the UNC and PCF between subjects with early AD and controls. Subjects with MCI exhibited significantly lower FA values on both sides of the PCF relative to controls. However, there were no significant differences between subjects with early AD and MCI for any measurement. Our results suggest that alterations in the PCF precede the onset of dementia. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.brainres.2009.06.052

Early Contrast-Enhanced Magnetic Resonance Imaging with Fluid-Attenuated Inversion Recovery in Multiple Sclerosis

Hiroshi Kataoka, Toshiaki Taoka, Satoshi Ueno

JOURNAL OF NEUROIMAGING Vol. 19 ( 3 ) page： 246 - 249 2009.7

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL PUBLISHING, INC

OBJECTIVE
Contrast-enhanced magnetic resonance imaging (MRI) with fluid-attenuated inversion recovery (contrast FLAIR) is particularly useful for the detection of meningeal lesions. However, whether contrast FLAIR is useful in multiple sclerosis (MS) remains uncertain. This study evaluated the usefulness of contrast FLAIR in MS.
PATIENTS AND METHODS
We prospectively studied the clinical histories and brain MRI studies of 6 patients with clinically definite MS diagnosed according to the new McDonald criteria. Contrast FLAIR (repetition time [TR] 9,000 ms; echo time [TE] 120 ms; inversion time [TI] 2,200 ms; 5-mm slice thickness, with a 1-mm interslice gap) was obtained with the use of a bolus of gadolinium diethylenetriamine pentaacetic acid.
RESULTS
Three enhancing plaques located in the periventricular or juxtacortical areas showed higher intensity on contrast FLAIR than on other MR sequences. In contrast, 8 enhancing plaques in the deep white matter or infratentorial areas showed no increased signals on contrast FLAIR.
CONCLUSION
Our findings suggest that early contrast-enhanced imaging with FLAIR may be helpful for the further detection of MS plaques, particularly those located in periventricular and juxtacortical lesions.
J Neuroimaging 2009;19:246-249.

DOI： 10.1111/j.1552-6569.2008.00315.x

TAOKA Tosiaki

Equilibrium Res Vol. 68 ( 3 ) page： 113 - 118 2009.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society for Equilibrium Research

CT and MRI are indispensable for routine medical examination of neurovascular disorders. This article describes the imaging findings in acute infarction and carotid plaques, knowledge of which is essential for clinics of equilibrium disorders. Diffusion-weighted images are indispensable for detecting acute infarction, and perfusion MRI also yields important information about the ischemic status. Carotid bifurcation is one of the frequent sites of involvement in atheromatous diseases. A variety of imaging modalities are available for the evaluation of carotid plaques, including conventional contrast angiography, CT, ultrasound, and MRI. MRI is a non-invasive imaging method that reflects the chemical composition, concentration, water content or physical status of the tissues examined.

DOI： 10.3757/jser.68.113

CiNii Books

A case with neonatal seizure due to cerebral infarction diagnosed by electroencephalogram and diffusion-weighted MRI

Other Link： http://search.jamas.or.jp/link/ui/2009271709

Vol. 19 ( 1 ) page： "S - 63"-"S-64" 2009.5

Reduced N-Acetylaspartate in the Basal Ganglia of a Patient with Anti-NMDA Receptor Encephalitis Reviewed

Hiroshi Kataoka, Josep Dalmau, Toshiaki Taoka, Satoshi Ueno

MOVEMENT DISORDERS Vol. 24 ( 5 ) page： 784 - 786 2009.4

Displacement of the Facial Nerve Course by Vestibular Schwannoma: Preoperative Visualization Using Diffusion Tensor Tractography Reviewed

Toshiaki Taoka, H. Hirabayashi, H. Nakagawa, M. Sakamoto, T. Akashi, T. Miyasaka, K. Kichikawa

Skull Base Vol. 19 ( 01 ) 2009.4

Urokinase intraventricular administration in extremely low birth weight infants with intraventricular hemorrhage Reviewed

ARAI Ikuyo, BOKU Eitaku, KAMAMOTO Tomoyuki, NISHIKUBO Toshiya, TAOKA Toshiaki, KAWAGUCHI Chiharu, TAKAHASHI Yukihiro

Vol. 18 ( 2 ) page： 51 - 58 2009.3

"Sukeroku sign" and "dent internal-capsule sign"aEuro"identification guide for targeting the subthalamic nucleus for placement of deep brain stimulation electrodes Reviewed

Toshiaki Taoka, Hidehiro Hirabayashi, Hiroyuki Nakagawa, Masahiko Sakamoto, Satoru Kitano, Junko Takahama, Nagaaki Marugami, Katsutoshi Takayama, Toshiaki Akashi, Toshiteru Miyasaka, Satoru Iwasaki, Naoko Kurita, Toshisuke Sakaki, Kimihiko Kichikawa

NEURORADIOLOGY Vol. 51 ( 1 ) page： 11 - 16 2009.1

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The purpose of this study was to assess the usefulness of signs ("Sukeroku sign" and "dent internal-capsule sign") for the recognition of subthalamic nucleus (STN).
Five Parkinson's disease cases in which there was a successful placement of deep brain stimulation (DBS) electrodes at the STN were retrospectively reviewed. Five radiologists who were not engaged in localization of STNs in clinical practice were asked to locate the STNs before and after instructions on the signs. We evaluated the deviation between the reader-located points and the location of the DBS electrode for which there had been a successful installation.
After instruction, there was a significant reduction in the deviation between the reader-located points and the DBS electrode. The time required for localization was also reduced after the instructions.
Sukeroku sign and dent internal-capsule sign are feasible indicators of STN and seem to be useful in helping to identify the STN.

DOI： 10.1007/s00234-008-0451-1

Cerebral Infarction Associated with Heparin-Induced Thrombocytopenia in a Patient with Encephalitis Reviewed

Kozue Saito, Makito Hirano, Miyuki Kajitani, Toshiaki Taoka, Kimihiko Kichikawa, Satoshi Ueno

INTERNAL MEDICINE Vol. 48 ( 1 ) page： 71 - 74 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN SOC INTERNAL MEDICINE

We report a patient who had cerebral infarction associated with heparin-induced thrombocytopenia ( HIT) during treatment of aseptic encephalitis. In patients with intracranial inflammation, such as ours, the possibility of HIT has to be considered when heparin is used, since inflammatory cerebral lesions often cause vascular damage, which is an aggravating factor for HIT-associated thrombosis.

DOI： 10.2169/internalmedicine.48.1486

Erratum:CT·MRI[Equilibrium Res Vol.68(3) 113-118]

Taoka Tosiaki

Equilibrium Research Vol. 68 ( 4 ) page： 183 - 183 2009

Superior Clinical Impact of FDG-PET Compared to MRI for the Follow-up of a Patient with Sacral Lymphoma

Yamamoto Yasuhiro, Taoka Toshiaki, Nakamine Hirokazu

Journal of Clinical and Experimental Hematopathology Vol. 49 ( 2 ) page： 109 - 115 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Lymphoreticular Tissue Research

DOI： 10.3960/jslrt.49.109

頭部の3.0T MRI 映像情報

田岡俊昭

Medical 41(14) 2009

頭部の3.0MRI

田岡俊昭

映像情報 Medical 41 page： 68 - 75 2009

連合線維

田岡俊昭

画像診断 29(5) page： 485 - 498 2009

画像検査で脳を探る

田岡俊昭

Equibulum Reserch 68 page： 113 - 118 2009

Prominent signal intensity of T(1)/T(2) prolongation in subcortical white matter of the anterior temporal region on conventional screening MRI of late preterm infants with normal development International journal

Chatchada Wuttikul, Toshiaki Taoka, Toshiaki Akashi, Hiroyuki Nakagawa, Toshiteru Miyasaka, Masahiko Sakamoto, Katsutoshi Takayama, Takeshi Wada, Satoru Kitano, Junko Takahama, Nagaaki Marugami, Kimihiko Kichikawa

MAGNETIC RESONANCE IMAGING Vol. 26 ( 10 ) page： 1374 - 1380 2008.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Purpose: This study discusses prominent signal intensity of T(1)/T(2) prolongation of subcortical white matter within the anterior temporal region in premature infant brains that radiologists may encounter when interpreting conventional screening MRIs.
Materials and Methods: T(1)- and T(2)-weighted images of 69 preterm and term infants with no neurological abnormalities or developmental delays were evaluated retrospectively for areas of prominent signal intensity of T(1)/T(2) prolongation in while matter. We measured signal intensities of anterior temporal white matter, deep temporal white matter, frontopolar white matter and subcortical white matter of the precentral gyrus. We accessed chronological changes in signal intensity in the anterior and deep temporal white matter. We also analyzed variance tests among the signal intensity ratios to the ipsilateral thalamus of white matter areas by gestational age.
Results: There was high frequency of prominent signal intensity of T(1)/T(2) prolongation in the temporal tip, particularly at a gestational age of 36-38 weeks. Signal intensity ratio of the anterior temporal white matter was lower on T(1)-weighted images and higher on T(2)-weighted images, and the finding became less prominent with increasing gestational age. The signal intensity ratios of anterior temporal white matter at a gestational age of 36-37 weeks and 38-39 weeks were significantly different from other regions.
Conclusion: Prominent signal intensity of T(1)/T(2) prolongation of subcortical white matter of the anterior temporal region is seen in normal premature infants, especially those at 36-39 gestational weeks. Although it is a prominent finding. radiologists Should understand that these findings do not represent a pathological Condition. (C) 2008 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.mri.2008.04.014

Initial experience of using the filter protection device during carotid artery stenting in Japan (Radiation Medicine - Medical Imaging and Radiation Oncology (2008) 26, (348-354) DOI: 10.1007/s11604-008-0239-6)

Takayama K., Nakagawa H., Iwasaki S., Taoka T., Miyasaka T., Myouchin K., Wada T., Sakamoto M., Fukusumi A., Nakagawa I., Kurokawa S., Kichikawa K.

Radiation Medicine - Medical Imaging and Radiation Oncology Vol. 26 ( 8 ) page： 516 - 517 2008.10

Initial experience of using the filter protection device during carotid artery stenting in Japan.

Takayama K, Nakagawa H, Iwasaki S, Taoka T, Miyasaka T, Myouchin K, Wada T, Sakamoto M, Fukusumi A, Nakagawa I, Kurokawa S, Kichikawa K

Radiation medicine Vol. 26 ( 8 ) page： 516 - 7 2008.10

Initial experience of using the filter protection device during carotid artery stenting in Japan (vol 26, pg 348, 2008)

Takayama, K; Nakagawa, H; Iwasaki, S; Taoka, T; Miyasaka, T; Myouchin, K; Wada, T; Sakamoto, M; Fukusumi, A; Nakagawa, I; Kurokawa, S; Kichikawa, K

RADIATION MEDICINE Vol. 26 ( 8 ) page： 516 - 517 2008.10

Katsutoshi Takayama, Hiroyuki Nakagawa, Satoru Iwasaki, Toshiaki Taoka, Toshiteru Miyasaka, Kaoru Myouchin, Takeshi Wada, Masahiko Sakamoto, Akio Fukusumi, Ichiro Nakagawa, Shinichiro Kurokawa, Kimihiko Kichikawa

Radiation Medicine - Medical Imaging and Radiation Oncology Vol. 26 ( 8 ) page： 516 - 517 2008.10

Discriminating between silent cerebral infarction and deep white matter hyperintensity using combinations of three types of magnetic resonance images: a multicenter observer performance study Reviewed

Makoto Sasaki, Toshinori Hirai, Toshiaki Taoka, Shuichi Higano, Chieko Wakabayashi, Eiji Matsusue, Masahiro Ida

NEURORADIOLOGY Vol. 50 ( 9 ) page： 753 - 758 2008.9

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Introduction We attempted to determine the most appropriate combination of magnetic resonance (MR) images that can accurately detect and discriminate between asymptomatic infarction and deep white matter hyperintensity (DWMH); these lesions have different clinical implications and are occasionally confused.
Materials and methods We performed an observer performance analysis using cerebral MR images of 45 individuals with or without asymptomatic small white matter infarction and/or mild DWMH who participated in a physical checkup program at four institutions. Six observers interpreted whether infarction and/or DWMH existed in combinations of two or three image types of the T1-weighted images (T1WI), T2-weighted images (T2WI), and fluid-attenuated inversion recovery (FLAIR) images. The observers' performance was evaluated with a receiver operating characteristic (ROC) analysis.
Results The averaged area under the ROC curve (Az) for detecting a infarction was significantly larger in the combination of all the three image types (0.95) than that in any combinations of the two image types (T1WI and FLAIR images, 0.87; T2WI and FLAIR images, 0.85; T1WI and T2WI, 0.86). The Az for detecting DWMH was significantly smaller in the combination of T1WI and T2WI (0.79) than that in other image combinations (T1WI and FLAIR, 0.89; T2WI and FLAIR, 0.91; T1WI, T2WI, and FLAIR, 0.90).
Conclusion The combination of T1WI, T2WI, and FLAIR images is required to accurately detect both small white matter infarction and mild DWMH.

DOI： 10.1007/s00234-008-0406-6

Diffusion tensor tractography of the Meyer loop in cases of temporal lobe resection for temporal lobe epilepsy: Correlation between postsurgical visual field defect and anterior limit of Meyer loop on tractography

T. Taoka, M. Sakamoto, H. Nakagawa, H. Nakase, S. Iwasaki, K. Takayama, K. Taoka, T. Hoshida, T. Sakaki, K. Kichikawa

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 29 ( 7 ) page： 1329 - 34 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: Visual field defects sometimes occur after temporal resection surgery. Our purpose was to evaluate the correlation between visual field defects caused by temporal lobe resection and the degree of resection of the Meyer loop, as assessed by diffusion tensor tractography.
MATERIALS AND METHODS: We examined 14 patients who underwent temporal resection for temporal lobe epilepsy. We obtained presurgical tractographies and then measured the distance between the temporal tip and the anterior limit of the Meyer loop (T-M distance). The degree of resection of the Meyer loop was defined as the distance from the anterior limit of the Meyer loop to the posterior limit of the temporal lobe resection (M-R distance). This was calculated by subtracting the T-M distance from the measured distance between the temporal tip and the posterior limit of the resection (T-R distance).
RESULTS: The mean T-M distance was 36.6 mm. The interindividual variation of the distance ranged from 30.0 to 43.2 mm. Although there was no statistically significant correlation between the extent of the visual field defect and the T-R distance, there was a statistically significant correlation between the degree of the visual field defect and the M-R distance.
CONCLUSION: The range of interindividual variation for the position of the Meyer loop was rather large, indicating that this variation is the key factor in visual field defects after temporal lobectomy, and the visual field defect appears to be predicted by presurgical tractography. Evaluation of the Meyer loop through the use of tractography seems to be a feasible method, which can be used to predict the visual field defect after temporal lobe resection.

DOI： 10.3174/ajnr.A1101

Initial experience of using the filter protection device during carotid artery stenting in Japan Reviewed

RADIATION MEDICINE Vol. 26 ( 6 ) page： 348 - 354 2008.7

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Purpose. No filter protection devices for carotid artery stenting (CAS) have been formally approved for use in Japan; however, as of April 2008, the Angioguard XP (AGXP) was approved. This article describes our initial results using the AGXP during CAS for the treatment of carotid artery stenosis.
Material and methods. A group of 15 patients (14 men) with a mean age of 72.3 years (range 53-81 years) were treated by CAS using the AGXP. Among them, 10 were symptomatic with >50% stenosis of the common or internal carotid artery (ICA), and 5 were asymptomatic with >70% stenosis. The rates of technical success, peri-procedural stroke, ICA flow impairment, filter movement, and development of new ischemic lesions on diffusion-weighted imaging (DWI) were assessed.
Results. CAS using the AGXP was successful in all cases. There was one minor stroke, and flow impairment occurred in six patients. Filter movement averaged 1.9 vertebral bodies. DWI showed new ipsilateral ischemic lesions in eight of the patients.
Conclusion. Initial clinical experience using the AGXP for CAS has been generally sufficient. However, attention must be paid to three problems when using the AGXP: the filter may move after placement; the filter may disturb blood flow in the ICA; and debris may pass around the filter.

DOI： 10.1007/s11604-008-0239-6

Diffusion tensor tractography of posterior cingulum and cognitive tests in Alzheimer's disease Reviewed

K. Kiuchi, M. Morikawa, T. Taoka, S. Kitamura, K. Nagauchi, K. Norimoto, Y. Inoue, M. Inoue, K. Kichikawa, T. Kishimoto

PSYCHIATRY AND CLINICAL NEUROSCIENCES Vol. 62 ( 1 ) page： S4 - S4 2008.2

Multiple cerebral aneurysms associated with Takayasu arteritis successfully treated with coil embolization

Katsutoshi Takayama, Hiroyuki Nakagawa, Satoru Iwasaki, Toshiaki Taoka, Kaoru Myouchin, Takeshi Wada, Masahiko Sakamoto, Akio Fukusumi, Shinichiro Kurokawa, Kimihiko Kichikawa

RADIATION MEDICINE Vol. 26 ( 1 ) page： 33 - 38 2008.1

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The cerebrovascular complications of Takayasu arteritis are primarily related to the presence of occlusive lesions. Cerebral aneurysms rarely occur as complications; only 18 cases have been reported thus far. The use of coil embolization to treat cerebral aneurysms occurring as a complication of Takayasu arteritis has not been previously reported. We report a case of Takayasu arteritis with a basilar tip aneurysm and a P1 segment aneurysm of the left posterior cerebral artery that were successfully treated with coil embolization. Because coil embolization for cerebral aneurysms associated with Takayasu arteritis requires the use of limited access routes that have extremely curved and tortuous courses, catheter navigation was difficult. The guide catheter, microcatheter, and guidewire must be selected and navigated with greater care than is usually required for common aneurysm embolization.

DOI： 10.1007/s11604-007-0184-9

Cerebral Sinus and Venous Thrombosis Associated with von Willebrand Factor, Independently of Factor VIII.

Terashima M, Kataoka H, Horikawa H, Nakagawa H, Taoka T, Matsumoto M, Saito K, Kichikawa K, Ueno S

Clinical medicine. Case reports Vol. 1 page： 29 - 32 2008

Signal changes of superior cerebellar peduncle on fluid-attenuated inversion recovery in progressive supranuclear palsy

Hiroshi Kataoka, Yasuyo Tonomura, Toshiaki Taoka, Satoshi Uenoa

PARKINSONISM & RELATED DISORDERS Vol. 14 ( 1 ) page： 63 - 5 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

Pathological changes of the superior cerebellar peduncle (SCP) can occur in PSP. We assessed the clinical history and signal changes in the SCP on fluid-attenuated inversion recovery (FLAIR) images of 12 patients with clinically probable PSP. Three control groups were studied: Parkinson's disease (PD), multiple system atrophy with predominant parkinsonian features (MSA-P), and healthy controls. Three patients who had clinically probable PSP showed increased FLAIR signals within the SCP. No subject with PD or MSA-P showed any signal changes of the SCP. The signal changes in the SCP on FLAIR may be one indicator for differentiating PSP from other parkinsonian diseases. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.parkreldis.2007.03.001

O2-47 Optic tractography for epilepsy surgery(The 41^<th> Congress of the Japan Epilepsy Society)

アルツハイマー病での側頭葉幹のテンソル解析

田岡俊昭, 森川将行, 坂本雅彦, 中川裕之, 岩崎聖, 明石敏昭, 宮坂俊輝, 高山勝年, 木内邦明, 岸本年史, 吉川公彦

認知神経科学 Vol. 10 ( 1 ) page： 39 - 42 2008

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：認知神経科学会

【要旨】拡散テンソル法は生体内の水の拡散の程度や、異方性を解析できる手法である。一般に白質神経路の障害では、拡散能が上昇し、拡散異方性が低下する傾向にある。拡散テンソル法による拡散能・拡散異方性の検討は、拡散テンソルトラクトグラフィーと組合せることにより、解剖学的により特異的な情報を得ることができると考えられる。Alzheimer病をはじめとした神経変性疾患の評価に、本手法が有用であることが示唆される。

DOI： 10.11253/ninchishinkeikagaku1999.10.39

Journal of the Japan Epilepsy Society Vol. 25 ( 3 ) page： 310 2007.9

A case of infantile Alexander disease diagnosed by magnetic resonance imaging and genetic analysis

SAKAKIBARA Takafumi, TAKAHASHI Yukihiro, FUKUDA Kazuyoshi, INOUE Tomomi, KUROSAWA Tomoko, NISHIKUBO Toshiya, SHIMA Midori, TAOKA Toshiaki, AIDA Noriko, TSUJINO Seiichi, KANAZAWA Naomi, YOSHIOKA Akira

Vol. 29 ( 8 ) page： 525 - 528 2007.9

A case of infantile Alexander disease diagnosed by magnetic resonance imaging and genetic analysis

Takafumi Sakakibara, Yukihiro Takahashi, Kazuyoshi Fukuda, Tomomi Inoue, Tomoko Kurosawa, Toshiya Nishikubo, Midori Shima, Toshiaki Taoka, Noriko Aida, Seiichi Tsujino, Naomi Kanazawa, Akira Yoshioka

BRAIN & DEVELOPMENT Vol. 29 ( 8 ) page： 525 - 8 2007.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We encountered a male infant with infantile Alexander disease presenting with megalencephaly and hydrocephalus as a neonate and subtle seizures at 3 months of age. At 6 months of age, bulbar paralysis appeared. Brain magnetic resonance imaging (MRI) showed abnormal findings with white matter involvement and a characteristic periventricular rim, satisfying the diagnostic criteria proposed by van der Knaap, except for MRI contrast. R239H mutation of glial fibrillary acidic protein gene was identified, representing a common cause of infantile-type Alexander disease. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.braindev.2007.02.002

Diffusivity and diffusion anisotropy of cerebellar peduncles in cases of spinocerebellar degenerative disease International journal

Toshiaki Taoka, Tesseki Kin, Hiroyuki Nakagawa, Makito Hirano, Masahiko Sakamoto, Takeshi Wada, Katsutoshi Takayama, Chatchada Wuttikul, Satoru Iwasaki, Satoshi Ueno, Kimihiko Kichikawa

NEUROIMAGE Vol. 37 ( 2 ) page： 387 - 93 2007.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Purpose: This study accessed the feasibility of using tractography-based analysis to evaluate the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of three cerebellar peduncles in subtypes of spinocerebellar degenerative disease.
Materials and methods: We examined 7 cases of dentatorubropallidoluysian atrophy (DRPLA), 4 cases of multiple system atrophy, cerebellar type (MSA-C), 4 cases of late cerebellar cortical atrophy (LCCA) and 8 controls. Diffusion tensor images were obtained, and tractographies of cerebellar peduncles were generated. ADC and FA along the cerebellar peduncles and volume of cerebellar peduncle were measured, and analyses of variance were made among the control and each spinocerebellar degenerative disease groups.
Results: There were statistically significant decrease in FA and volume and increase in ADC values between DRPLA cases and controls in all three cerebellar peduncles. On the other hand, MSA-C cases mainly showed statistically significant decreased FA and volume and increased ADC values in the middle cerebellar peduncle. LCCA cases did not show prominent difference in the three cerebellar peduncles.
Conclusion: The values of diffusivity and diffusion anisotropy of cerebellar peduncles evaluated by tractography based measurements seem to reflect characteristics of the different types of spinocerebellar degenerative diseases. Tractography- based measurements may be a feasible tool for differential diagnosis of spinocerebellar degenerative disease. (c) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.neuroimage.2007.05.028

Cerebral hemorrhage with angiographic extravasation immediately after carotid artery stenting

Katsutoshi Takayama, Hiroyuki Nakagawa, Satoru Iwasaki, Toshiaki Taoka, Takeshi Wada, Kaoru Myouchin, Masahiko Sakamoto, Akio Fukusumi, Kimihiko Kichikawa

Radiation Medicine - Medical Imaging and Radiation Oncology Vol. 25 ( 7 ) page： 359 - 363 2007.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Nature

Recognizing cerebral hyperperfusion syndrome with intracerebral hemorrhage following carotid artery stenting is critical because the mortality rate is high. This type of hemorrhage usually arises from within several hours to a few days after the procedure. Here we describe a putaminal hemorrhage with extravasation during angiography that developed immediately after carotid artery stenting. A search of the literature revealed only one other similar case report. The etiology of the intracerebral hemorrhage immediately after carotid stenting might be analogous to that of hypertensive hemorrhage. © 2007 Japan Radiological Society.

DOI： 10.1007/s11604-007-0147-1

Intracranial hemorrhage in full-term newborns : Two patients with superficial parenchymal and leptomeningial hemorrhage

Parasagittal Arachnoid Markings on the Inner Skull on Three-Dimensional CT: Relation between Hydrocephalus and Arachnoid Granules.

Taoka T, Ida Y, Nakagawa H, Iwasaki S, Sakamoto M, Fukusumi A, Takayama K, Wada T, Myochin K, Wuttikul C, Kichikawa K

The neuroradiology journal Vol. 20 ( 3 ) page： 259 - 64 2007.6

Vol. 17 ( 1 ) page： "S - 29"-"S-30" 2007.6

Successful percutaneous transluminal angioplasty and stenting for symptomatic intracranial vertebral artery stenosis using intravascular ultrasound virtual histology Reviewed

Katsutoshi Takayama, Toshiaki Taoka, Hiroyuki Nakagawa, Kaoru Myouchin, Takeshi Wada, Masahiko Sakamoto, Akio Fukusumi, Satoru Iwasaki, Shinichiro Kurokawa, Kimihiko Kichikawa

Radiation Medicine - Medical Imaging and Radiation Oncology Vol. 25 ( 5 ) page： 243 - 246 2007.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Nature

This is the first report of percutaneous transluminal angioplasty (PTA) of an intracranial artery applying intravascular ultrasound virtual histology (IVUS-VH), which has been recently developed for tissue characterization of coronary artery plaque. We report a case of successful PTA and stenting for symptomatic intracranial vertebral artery stenosis using IVUS-VH. © 2007 Japan Radiological Society.

DOI： 10.1007/s11604-007-0127-5

Parasagittal arachnoid markings on the inner skull on three-dimensional CT: Relation between hydrocephalus and arachnoid granules

Taoka T., Ida Y., Nakagawa H., Iwasaki S., Sakamoto M., Fukusumi A., Takayama K., Wada T., Myochin K., Wuttikul C., Kichikawa K.

Neuroradiology Journal Vol. 20 ( 3 ) page： 259 - 264 2007.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Neuroradiology Journal

The purpose of the study was to evaluate the number and size of arachnoid markings on the inner plate of the skull on 3D-CT. The subjects included 16 hydrocephalus and 26 non-hydrocephalus cases. We evaluated the correlation between age and both the number and sizes of the arachnoid markings, and compared them between hydrocephalus and non-hydrocephalus cases. We also evaluated cases exhibiting a "smooth cranium" that had no arachnoid markings at all on the inner plate. There was a positive correlation between age and the number of the arachnoid markings. There were no statistically significant differences in arachnoid markings between hydrocephalus and non-hydrocephalus cases, while, there were statistically significant differences in the frequency of "smooth cranium" findings in the population under ten years old. The "smooth cranium" can only be seen in hydrocephalus cases. These findings may be a clue to the morphological or functional changes of the arachnoid villi in hydrocephalus cases.

DOI： 10.1177/197140090702000301

Physiologic and pathologic statuses that show reduced relaxation time within the brain

Taoka T., Nakagawa H., Kichikawa K.

Japanese Journal of Clinical Radiology Vol. 52 ( 4 ) page： 555 - 566 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Clinical Radiology

Pathologic tissue within the brain usually shows elongated relaxation time reflecting large water content, and result in low signals on T1 weighted images and high signals on T2 weighted images. However, there are some statuses that show reduced relaxation times. In this article, we show the mechanism of the reduce in relaxation times and we review the physiologic and pathologic status that shows high signals on T1 weighted images and low signals on T2 weighted images.

Extensive neuroimaging of a transient lesion in the splenium of the corpus callosum

拡散テンソルtractographyを用いたアルツハイマー病患者における後部帯状束の検討 Reviewed

木内邦明, 森川将行, 田岡俊昭, 松田康裕, 長内清行, 山内崇平, 牧之段学, 則本和伸, 芳野浩樹, 井上雄一朗, 井上眞, 中川康司, 吉川公彦, 岸本年史

精神神経学雑誌 ( 2007特別 ) page： S161 - S161 2007.5

Treatable fluctuating parkinsonism and dementia in a patient with a dural arteriovenous fistula International journal

Miyuki Kajitani, Hajime Yagura, Makoto Kawahara, Makito Hirano, Satoshi Ueno, Kenta Fujimoto, Toshisuke Sakaki, Toshiaki Taoka, Hiroyuki Nakagawa, Kimihiko Kichikawa

MOVEMENT DISORDERS Vol. 22 ( 3 ) page： 437 - 439 2007.2

H. Shimizu, H. Kataoka, H. Yagura, M. Hirano, T. Taoka, S. Ueno

EUROPEAN JOURNAL OF NEUROLOGY Vol. 14 ( 1 ) page： E37 - E39 2007.1

Parasagittal arachnoid markings on the inner skull on three-dimensional CT: Relation between hydrocephalus and arachnoid granules Reviewed

Toshiaki Taoka, Y. Ida, H. Nakagawa, S. Iwasaki, M. Sakamoto, A. Fukusumi, K. Takayama, T. Wada, K. Myochin, C. Wuttikul, K. Kichikawa

Neuroradiology Journal Vol. 20 ( 3 ) page： 259 - 264 2007

Language：English Publishing type：Research paper (scientific journal) Publisher：Centauro SRL

DOI： 10.1177/197140090702000301

Displacement of the facial nerve course by vestibular schwannoma: Preoperative visualization using diffusion tensor tractography International journal

Toshiaki Taoka, Hidehiro Hirabayashi, Hiroyuki Nakagawa, Masahiko Sakamoto, Kaoru Myochin, Shinji Hirohashi, Satoru Iwasaki, Toshisuke Sakaki, Kimihiko Kichikawa

JOURNAL OF MAGNETIC RESONANCE IMAGING Vol. 24 ( 5 ) page： 1005 - 10 2006.11

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN WILEY & SONS INC

Purpose: To preoperatively visualize the course of the facial nerve, which is displaced by vestibular schwannoma, using diffusion tensor (DT) tractography, and to evaluate the agreement with surgical findings.
Material and Methods : The subjects were eight patients with vestibular schwannoma who had undergone removal surgery. DT MR images were obtained and tracts that were considered to represent the facia nerve were constructed. We assess the success rate for tract construction and evaluated the agreement between tractography findings and surgery.
Results: We obtained a tract that connected the internal auditory meatus and brainstem, and was considered to represent the facial nerve in seven of the eight cases. The course of the constructed tract agreed with surgical findings in five of these seven cases. One exception was a case in which the tumor was too large to enable intraoperative observation of the facial nerve; however, the facial nerve appeared to be displaced anteriorly at intracapsular resection, in agreement with tractography. In the other case, the schwannoma was mostly cystic.
Conclusion: Tractographs constructed using MR tensor images enabled to to identify tracts considered to represent facial nerves. We consider DT tractography to be a useful tool for preoperatively predicting facial nerve displacement in vestibular schwannoma.

DOI： 10.1002/jmri.20725

Global and region-specific analyses of apparent diffusion coefficient in dentatorubral-pallidoluysian atrophy.

Kin T, Hirano M, Taoka T, Furiya Y, Kataoka H, Kichikawa K, Ueno S

AJNR. American journal of neuroradiology Vol. 27 ( 7 ) page： 1463 - 6 2006.8

Global and region-specific analyses of apparent diffusion coefficient in dentatorubral-pallidoluysian atrophy Reviewed

T. Kin, M. Hirano, T. Taoka, Y. Furiya, H. Kataoka, K. Kichikawa, S. Ueno

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 27 ( 7 ) page： 1463 - 1466 2006.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant spinocerebellar ataxia. Techniques for the quantitative assessment of neurodegenerative lesions remain to be established in this disease. We attempted to quantify global and region-specific neuro. degeneration in DRPLA using analysis of apparent diffusion coefficient (ADC) maps.
METHODS: Diffusion-weighted images (b = 1000 s/mm(2)) by echo-planar sequences were obtained with the use of a 1.5T clinical scanner. Whole-brain histogram and region of interest (ROI) analyses of ADC values as well as conventional MR imaging studies were performed in 6 patients with genetically confirmed DRPLA.
RESULTS: Histograms demonstrated significantly higher mean ADC values in the patients than in age- and sex-matched control subjects (P <.01). 1901 analysis revealed that the patients had significantly higher ADC values in the cerebellum and globus pallidus, preferentially affected regions (P <.05), but not in the thalamus, the region relatively spared in this disease. ADC values in the white matter were higher only in patients with adult-onset disease. Histogram analyses could more sensitively identify abnormalities than ROI analyses, because the former avoided errors associated with setting ROIs and thus had smaller P values on statistical analysis than the latter.
CONCLUSIONS: Histogram ADC analyses were more sensitive for the detection of neurodegeneration in DRPLA than ROI analyses, whereas ROI analyses revealed regional alterations reflecting the distribution of pathologic changes. Thus, histogram and ROI analyses complement each other and may permit the sensitive, quantitative evaluation of neurodegeneration in DRPLA, especially that involving the globus pallidus showing normal T2 signals.

Global and region-specific analyses of apparent diffusion coefficient in dentatorubral-pallidoluysian atrophy

Kin T., Hirano M., Taoka T., Furiya Y., Kataoka H., Kichikawa K., Ueno S.

American Journal of Neuroradiology Vol. 27 ( 7 ) page： 1463 - 1466 2006.8

Language：English Publishing type：Research paper (scientific journal) Publisher：American Journal of Neuroradiology

BACKGROUND AND PURPOSE: Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant spinocerebellar ataxia. Techniques for the quantitative assessment of neurodegenerative lesions remain to be established in this disease. We attempted to quantify global and region-specific neurodegeneration in DRPLA using analysis of apparent diffusion coefficient (ADC) maps. METHODS: Diffusion-weighted images (b = 1000 s/mm2) by echo-planar sequences were obtained with the use of a 1.5T clinical scanner. Whole-brain histogram and region of interest (ROI) analyses of ADC values as well as conventional MR imaging studies were performed in 6 patients with genetically confirmed DRPLA. RESULTS: Histograms demonstrated significantly higher mean ADC values in the patients than in age-and sex-matched control subjects (P < .01). ROI analysis revealed that the patients had significantly higher ADC values in the cerebellum and globus pallidus, preferentially affected regions (P < .05), but not in the thalamus, the region relatively spared in this disease. ADC values in the white matter were higher only in patients with adult-onset disease. Histogram analyses could more sensitively identify abnormalities than ROI analyses, because the former avoided errors associated with setting ROIs and thus had smaller P values on statistical analysis than the latter. CONCLUSIONS: Histogram ADC analyses were more sensitive for the detection of neurodegeneration in DRPLA than ROI analyses, whereas ROI analyses revealed regional alterations reflecting the distribution of pathologic changes. Thus, histogram and ROI analyses complement each other and may permit the sensitive, quantitative evaluation of neurodegeneration in DRPLA, especially that involving the globus pallidus showing normal T2 signals.

Evaluation of arteriosclerotic changes in the intracranial carotid artery using the calcium score obtained on plain cranial computed tomography scan: Correlation with angiographic changes and clinical outcome International journal

Toshiaki Taoka, Satoru Iwasaki, Hiroyuki Nakagawa, Masahiko Sakamoto, Akio Fukusumi, Katsutoshi Takayama, Takeshi Wada, Kaoru Myochin, Shinji Hirohashi, Kimihiko Kichikawa

JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Vol. 30 ( 4 ) page： 624 - 8 2006.7

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Purpose: This study evaluated the correlation between quantified calcification of the carotid siphon and arteriosclerotic changes on angiography as well as clinical outcome. We used the calcium score obtained from intracranial carotid arteries on plain CT.
Method/Materials: We examined carotid siphons of 72 consecutive patients who had undergone both plain CT and angiography of the brain. We calculated calcium scores of the carotid siphon. Arteriosclerotic changes on angiography were categorized as "smooth," "irregular," or "stenosis." We assessed the correlation between the scores and arteriosclerotic changes both in the carotid siphon and the bifurcation. We reviewed clinical records approximately 2 years after examination and evaluated the scores of patients who did and did not experience cerebral strokes.
Results: In the evaluation between angiographic findings of siphon and calcium score of the siphon, there were statistically significant differences between the "smooth" and "irregular", "irregular" and "stenosis" and the "smooth" and "stenosis". In the evaluation between angiographic findings of bifurcation and the score of the siphon, a statistically significant difference was only seen between "smooth" and "stenosis". No significant differences in calcium scores were observed between patients groups who did or did not experience a cerebral stroke.
Conclusions: There were a positive correlation between calcium scores on CT and angiographic changes of arteriosclerosis in the siphon as well as bifurcation, indicating angiographic changes can be predicted using calcium scores. However, the degree of calcification in the siphon cannot be used to predict the possibility of a future cerebral stroke.

DOI： 10.1097/00004728-200607000-00012

White matter T2 hyperintensity development and clinical deterioration after status epilepticus in a patient with dentatorubral-pallidoluysian atrophy International journal

M Takamure, M Hirano, T Taoka, S Ueno

CLINICAL NEUROLOGY AND NEUROSURGERY Vol. 108 ( 5 ) page： 482 - 5 2006.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Serial T2-weighted magnetic resonance imaging in a 29-year-old woman with juvenile type dentatorubral-pallidoluysian atrophy (DRPLA) demonstrated that a cerebral white matter hyperintensity appeared within 2 months after status epilepticus and persisted for more than 20 months. The patient had rapidly progressive mental regression and became akinetic after status epilepticus. The chronological relationship between the signal changes and the clinical deterioration suggested that the epilepsy, at least in part, contributed to the progression of white matter degeneration, the hallmark of DRPLA. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.clineuro.2005.01.011

Serial therapy-induced changes in tumor shape in cervical cancer and their impact on assessing tumor volume and treatment response Reviewed

NA Mayr, WTC Yuh, T Taoka, JZ Wang, DH Wu, JF Montebello, SL Meeks, AC Paulino, VA Magnotta, M Adli, JI Sorosky, MV Knopp, JM Buatti

AMERICAN JOURNAL OF ROENTGENOLOGY Vol. 187 ( 1 ) page： 65 - 72 2006.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ROENTGEN RAY SOC

OBJECTIVE. The purpose of this study was to evaluate the patterns and distribution of tumor shape and its temporal change during radiation therapy (RT) in cervical cancer and the effect of tumor configuration changes on the correlation between region of interest (ROI)-based and diameter-based MRI tumor measurement.
MATERIALS AND METHODS. Serial MRI examinations (T1-weighted and T2-weighted images) were performed in 60 patients (age range, 29-75 years; mean, 53.3 years) with advanced cervical cancer (stages IB2-IVB/recurrent) who were treated with RT at four time points: start of RT, during RT (at 2-2.5 and at 4-5 weeks of RT), and post-RT. Tumor configuration was classified qualitatively into oval, lobulated, and complex based on MR film review. Two methods of tumor volume measurement were compared: ellipsoid computation of three orthogonal diameters (diameter based) and ROI volumetry by delineating the entire tumor volume on the MR workstation (ROI based). Temporal changes of tumor shape and the respective tumor volumes measured by the two methods were analyzed using linear regression analysis.
RESULTS. Most tumors (70%) had a non-oval (lobulated and complex) shape before RT and became increasingly irregular during and after RT 84% at 2-2.5 weeks of RT (p = 0.037), 86% (p = 0.025) at 4-5 weeks, and 96% post-RT (p = 0.010), compared with 70% pre-RT. Diameter-based and ROI-based measurement correlated well before RT (r = 0.89) but not during RT (r = 0.68 at 2-2.5 weeks, r = 0.67 at 4-5 weeks of RT).
CONCLUSION. Most cervical cancers are not oval in shape pretherapy, and they become increasingly irregular during and after therapy because of nonconcentric tumor shrinkage. ROI-based volumetry, which can optimally measure irregular volumes, may provide better response assessment during treatment than diameter-based measurement.

DOI： 10.2214/AJR.05.0039

Taoka T., Iwasaki S., Nakagawa H., Sakamoto M., Fukusumi A., Takayama K., Wada T., Myochin K., Hirohashi S., Kichikawa K.

Journal of Computer Assisted Tomography Vol. 30 ( 4 ) page： 624 - 628 2006.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Computer Assisted Tomography

PURPOSE:: This study evaluated the correlation between quantified calcification of the carotid siphon and arteriosclerotic changes on angiography as well as clinical outcome. We used the calcium score obtained from intracranial carotid arteries viewed on plain CT. METHOD/MATERIALS:: We examined carotid siphons of 72 consecutive patients who had undergone both plain CT and angiography of the brain. We calculated calcium scores of the carotid siphon. Arteriosclerotic changes on angiography were categorized as "smooth," "irregular," or "stenosis." We assessed the correlation between the scores and arteriosclerotic changes both in the carotid siphon and the bifurcation. We reviewed clinical records approximately 2 years after examination and evaluated the scores of patients who did and did not experience cerebral strokes. RESULTS:: In the evaluation between angiographic findings of siphon and calcium score of the siphon, there were statistically significant differences between the "smooth" and "irregular", "irregular" and "stenosis" and the "smooth" and "stenosis". In the evaluation between angiographic findings of bifurcation and the score of the siphon, a statistically significant difference was only seen between "smooth" and "stenosis". No significant differences in calcium scores were observed between patients groups who did or did not experience a cerebral stroke. CONCLUSIONS:: There were a positive correlation between calcium scores on CT and angiographic changes of arteriosclerosis in the siphon as well as bifurcation, indicating angiographic changes can be predicted using calcium scores. However, the degree of calcification in the siphon cannot be used to predict the possibility of a future cerebral stroke. Copyright © 2006 by Lippincott Williams & Wilkins.

DOI： 10.1097/00004728-200607000-00012

Pituitary stalk compression by the dorsum sellae: possible cause for late childhood onset growth disorders International journal

T Taoka, S Iwasaki, S Okamoto, M Sakamoto, H Nakagawa, S Otake, M Fujioka, S Hirohashi, K Kichikawa

MAGNETIC RESONANCE IMAGING Vol. 24 ( 5 ) page： 651 - 6 2006.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Purpose: The purpose of this study was to evaluate the relationship between pituitary stalk compression by the dorsum sellae and clinical or laboratory findings in short stature children.
Materials and Methods: We retrospectively reviewed magnetic resonance images of the pituitary gland and pituitary stalk for 34 short stature children with growth hormone (GH) deficiency and 24 age-matched control cases. We evaluated the degree of pituitary stalk compression caused by the dorsum sellae. Body height, GH level, pituitary height and onset age of the short stature were statistically compared between cases of pituitary stalk compression with associated stalk deformity and cases without compression.
Results: Compression of the pituitary stalk with associated stalk deformity was seen in nine cases within the short stature group. There were no cases observed in the control group. There were no significant differences found for body height, GH level and pituitary height between the cases of pituitary stalk compression with associated stalk deformity and cases without compression. However, a significant difference was seen in the onset age between cases with and without stalk compression.
Conclusion: Pituitary stalk compression with stalk deformity caused by the dorsum sellae was significantly correlated with late childhood onset of short stature. (C) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.mri.2005.12.015

Diffusion anisotropy and diffusivity of white matter tracts within the temporal stem in Alzheimer disease: evaluation of the "tract of interest" by diffusion tensor tractography.

Taoka T, Iwasaki S, Sakamoto M, Nakagawa H, Fukusumi A, Myochin K, Hirohashi S, Hoshida T, Kichikawa K

AJNR. American journal of neuroradiology Vol. 27 ( 5 ) page： 1040 - 5 2006.5

Diffusion anisotropy and diffusivity of white matter tracts within the temporal stem in Alzheimer disease: Evaluation of the "tract of interest" by diffusion tensor tractography

Taoka T., Iwasaki S., Sakamoto M., Nakagawa H., Fukusumi A., Myochin K., Hirohashi S., Hoshida T., Kichikawa K.

American Journal of Neuroradiology Vol. 27 ( 5 ) page： 1040 - 1045 2006.5

Language：English Publishing type：Research paper (scientific journal) Publisher：American Journal of Neuroradiology

PURPOSE: Our aim was to determine whether diffusion anisotropy and diffusivity of white matter tracts of the temporal stem in patients with Alzheimer (AD) can be evaluated independently by using diffusion tensor tractography. MATERIALS AND METHODS: Subjects included 15 patients with AD (11 women and 4 men; mean age, 74 years) and 15 age-matched control subjects (11 women and 4 men; mean age, 72 years). Diffusion tensor images were acquired by using echo-planar imaging. We drew tractographies of the uncinate fasciculus, inferior occipitofrontal fasciculus, and Meyer's loop, with diffusion tensor analysis software. We measured diffusion anisotropy, diffusivity, and the number of voxels along the "tracts of interest" and used the Student t test to compare results between patients with AD and controls. RESULTS: Values of diffusion anisotropy of the bilateral uncinate fasciculus and left inferior occipitofrontal fasciculus were significantly lower for patients with AD than for controls. Also, values of diffusivity in the bilateral uncinate fasciculus were significantly greater for patients with AD than for controls. There was no significant difference in diffusion anisotropy or diffusivity along Meyer's loop between the 2 groups. There was no significant difference in the number of voxels included in all constructed tracts between patients with AD and controls. CONCLUSION: White matter tracts of the temporal stem can be evaluated independently by using diffusion tensor tractography, which appears to be a promising technique for determining changes in white matter in degenerative diseases.

Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy

Apparent diffusion coefficient in dentatorubral-pallidoluysian atrophy Reviewed

Tesseki Kin, Makito Hirano, Toshiaki Taoka, Hiroshi Kataoka, Foshiko Furiya, Hirohide Asai, Kimihiko Kichikawa, Satoshi Ueno

ANNALS OF NEUROLOGY Vol. 60 page： S53 - S53 2006

Taoka T., Sakamoto M., Iwasaki S., Nakagawa H., Fukusumi A., Hirohashi S., Taoka K., Kichikawa K., Hoshida T., Sakaki T.

American Journal of Neuroradiology Vol. 26 ( 4 ) page： 797 - 803 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：American Journal of Neuroradiology

BACKGROUND AND PURPOSE: Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect. METHODS: We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side. RESULTS: On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery. CONCLUSION: Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery. © American Society of Neuroradiology.

Proton MR spectroscopy of adult-onset dentatorubral-pallidoluysian atrophy

Kin T., Hirano M., Taoka T., Takamure M., Furiya Y., Kichikawa K., Ueno S.

Magnetic Resonance in Medical Sciences Vol. 4 ( 3 ) page： 123 - 127 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Magnetic Resonance in Medical Sciences

Purpose: To quantify impairment of the basal ganglia (globus pallidus and thalamus) in adult-onset dentatorubral-pallidoluysian atrophy (DRPLA). Methods: Five patients with genetically definite adult-onset DRPLA (aged 51 to 65 years, mean 55.6 years) and 5 age- and sex-matched healthy controls underwent conventional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) of the brain in the voxels predominantly containing the globus pallidus or the thalamus. Results: Conventional MRI studies showed apparently normal intensities in the globus pallidus and thalamus. MRS showed that the choline (Cho)/creatine (Cr) ratio for the patients' globus pallidus, the region preferentially affected in DRPLA, was significantly higher than that in the controls (p<0.05). The N-acetylaspartate (NAA)/Cr ratio for the globus pallidus and the Cho/Cr and NAA/Cr ratios for the thalamus, the region relatively spared in this disease, did not differ significantly between the patients and controls. Conclusions: MRS may sensitively and specifically detect biochemical alterations in susceptible regions of patients with adult-onset DRPLA.

DOI： 10.2463/mrms.4.123

Ferucarbotran-enhanced perfusion MR imaging of the liver in patients with hypervascular hepatocellular carcinomas Reviewed

Shinji Hirohashi, Satoru Kitano, Toshiaki Taoka, Nagaaki Marugami, Kouji Ueda, Kimihiko Kichikawa

Academic Radiology Vol. 12 ( 5 ) page： S45 2005.5

Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy International journal

T Taoka, M Sakamoto, S Iwasaki, H Nakagawa, A Fukusumi, S Hirohashi, K Taoka, K Kichikawa, T Hoshida, T Sakaki

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 26 ( 4 ) page： 797 - 803 2005.4

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect.
METHODS: We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side.
RESULTS: On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery.
CONCLUSION. Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery.

Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy Reviewed

T Taoka, M Sakamoto, S Iwasaki, H Nakagawa, A Fukusumi, S Hirohashi, K Taoka, K Kichikawa, T Hoshida, T Sakaki

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 26 ( 4 ) page： 797 - 803 2005.4

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

BACKGROUND AND PURPOSE: Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect.
METHODS: We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side.
RESULTS: On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery.
CONCLUSION. Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery.

Evaluation of delayed image of 18F FDG-PET in diagnosis of pulmonary lesions

Sakamoto M., Imai T., Shingai T., Nishimoto Y., Taoka T., Koukawa K., Hirohashi S., Yoshimura H., Yoshikawa K.

Japanese Journal of Clinical Radiology Vol. 50 ( 1 ) page： 148 - 154 2005.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Clinical Radiology

We evaluated the usefulness of dual time point 18F-FDG PET by comparing two groups of pulmonary lesions (38 malignant tumors and 29 benign lesions). Among standardized uptake value (SUV) of early image (SUVe), SUV of delayed image (SUVd), Retention Index (RI), and SUVe combined with RI (SUVe-RI), diagnosis by SUVe-RI revealed the best result (sensitivity: 78.9%, specificity: 82.8%). We conclude that dual time point FDG-PET is better method than early or delayed single acquisition to diagnose pulmonary lesions.

Evaluation of extraocular muscles using dynamic contrast enhanced MRI in patients with chronic thyroid orbitopathy.

Taoka T, Sakamoto M, Nakagawa H, Fukusumi A, Iwasaki S, Taoka K, Kichikawa K

Journal of computer assisted tomography Vol. 29 ( 1 ) page： 115 - 20 2005.1

Evaluation of extraocular muscles using dynamic contrast enhanced MRI in patients with chronic thyroid orbitopathy

Taoka T., Sakamoto M., Nakagawa H., Fukusumi A., Iwasaki S., Taoka K., Kichikawa K.

Journal of Computer Assisted Tomography Vol. 29 ( 1 ) page： 115 - 120 2005.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Computer Assisted Tomography

Objective: The purpose of the current study is to investigate the underlying pathophysiological changes of extraocular muscle (EOM) in Graves orbitopathy using dynamic contrast MR imaging and to correlate these MR functional changes with the anatomic abnormalities. Methods: EOMs of 16 patients with Graves disease and 12 normal volunteers were examined by dynamic enhanced MRI. We quantified the peak enhancement ratio of EOMs and calculated the ratio versus temporalis muscle and the ratio of maximum upslope versus temporalis muscle. We compared the ratios between normal volunteers and patient groups. Results: Mean of peak enhancement ratio values for the EOMs in patients with Graves disease tends to decrease according to the severity of the anatomic and clinical changes. The mean maximum upslope also decreased according to the severity of the disease for EOMs. Conclusion: Hemodynamic information obtained by dynamic contrast enhanced MRI is useful in evaluating the clinical course of thyroid orbitopathy.

DOI： 10.1097/01.rct.0000146112.56194.24

Evaluation of extraocular muscles using dynamic contrast enhanced MRI in patients with chronic thyroid orbitopathy Reviewed

T Taoka, M Sakamoto, H Nakagawa, A Fukusumi, A Iwasaki, K Taoka, K Kichikawa

JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Vol. 29 ( 1 ) page： 115 - 120 2005.1

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Objective: The purpose of the current study is to investigate the underlying pathophysiological changes of extraocular muscle (EOM) in Graves orbitopathy using dynamic contrast MR imaging and to correlate these MR functional changes with the anatomic abnormalities.
Methods: EOMs of 16 patients with Graves disease and 12 normal volunteers were examined by dynamic enhanced MRI. We quantified the peak enhancement ratio of EOMs and calculated the ratio versus temporalis muscle and the ratio of maximum upslope versus temporalis muscle. We compared the ratios between normal volunteers and patient groups.
Results: Mean of peak enhancement ratio values for the EOMs in patients with Graves disease tends to decrease according to the severity of the anatomic and clinical changes. The mean maximum upslope also decreased according to the severity of the disease for EOMs.
Conclusion: Hemodynamic information obtained by dynamic contrast enhanced MRI is useful in evaluating the clinical course of thyroid orbitopathy.

DOI： 10.1097/01.rct.0000146112.56194.24

Proton MR spectroscopy of adult-onset dentatorubral-pallidoluysian atrophy

Tesseki Kin, Makito Hirano, Toshiaki Taoka, Miwa Takamure, Yoshiko Furiya, Kimihiko Kichikawa, Satoshi Ueno

Magnetic Resonance in Medical Sciences Vol. 4 ( 3 ) page： 123 - 7 2005

Language：English Publishing type：Research paper (scientific journal)

Purpose: To quantify impairment of the basal ganglia (globus pallidus and thalamus) in adult-onset dentatorubral-pallidoluysian atrophy (DRPLA). Methods: Five patients with genetically definite adult-onset DRPLA (aged 51 to 65 years, mean 55.6 years) and 5 age- and sex-matched healthy controls underwent conventional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) of the brain in the voxels predominantly containing the globus pallidus or the thalamus. Results: Conventional MRI studies showed apparently normal intensities in the globus pallidus and thalamus. MRS showed that the choline (Cho)/creatine (Cr) ratio for the patients' globus pallidus, the region preferentially affected in DRPLA, was significantly higher than that in the controls (p&lt
0.05). The N-acetylaspartate (NAA)/Cr ratio for the globus pallidus and the Cho/Cr and NAA/Cr ratios for the thalamus, the region relatively spared in this disease, did not differ significantly between the patients and controls. Conclusions: MRS may sensitively and specifically detect biochemical alterations in susceptible regions of patients with adult-onset DRPLA.

DOI： 10.2463/mrms.4.123

Proton MR Spectroscopy of Adult-onset Dentatorubral-pallidoluysian Atrophy

KIN Tesseki, HIRANO Makito, TAOKA Toshiaki, TAKAMURE Miwa, FURIYA Yoshiko, KICHIKAWA Kimihiko, UENO Satoshi

Magnetic Resonance in Medical Sciences Vol. 4 ( 3 ) page： 123 - 127 2005

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine

Purpose: To quantify impairment of the basal ganglia (globus pallidus and thalamus) in adult-onset dentatorubral-pallidoluysian atrophy (DRPLA). Methods: Five patients with genetically definite adult-onset DRPLA (aged 51 to 65 years, mean 55.6 years) and 5 age- and sex-matched healthy controls underwent conventional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) of the brain in the voxels predominantly containing the globus pallidus or the thalamus. Results: Conventional MRI studies showed apparently normal intensities in the globus pallidus and thalamus. MRS showed that the choline (Cho)/creatine (Cr) ratio for the patients' globus pallidus, the region preferentially affected in DRPLA, was significantly higher than that in the controls (p<0.05). The N-acetylaspartate (NAA)/Cr ratio for the globus pallidus and the Cho/Cr and NAA/Cr ratios for the thalamus, the region relatively spared in this disease, did not differ significantly between the patients and controls. Conclusions: MRS may sensitively and specifically detect biochemical alterations in susceptible regions of patients with adult-onset DRPLA.

DOI： 10.2463/mrms.4.123

Retinotopy in Lateral Occipital Cortex

軽度脳虚血による遅発性神経細胞死と進行性認知障害

藤岡政行, 田岡俊昭, 松尾嘉之, 三島健一, 御興久美子, 近藤洋一, 津田聖一, 吉川哲也, 藤原道弘, 浅野孝雄, 榊寿右, 宮崎章宏, Darren Park, Bo, K. Siesjo

脳循環代謝 page： 17, 53 - 60 2005

KAIDO Takanobu, HOSHIDA Tohru, TAOKA Toshiaki, SAKAKI Toshisuke

Vol. 26 ( 3 ) page： 139 - 143 2004.12

Clinically mild encephalitis/encephalopathy with a reversible splenial lesion.

Tada H, Takanashi J, Barkovich AJ, Oba H, Maeda M, Tsukahara H, Suzuki M, Yamamoto T, Shimono T, Ichiyama T, Taoka T, Sohma O, Yoshikawa H, Kohno Y

Neurology Vol. 63 ( 10 ) page： 1854 - 1858 2004.11

Clinically mild encephalitis/encephalopathy with a reversible splenial lesion

Tada H., Takanashi J.I., Barkovich A.J., Oba H., Maeda M., Tsukahara H., Suzuki M., Yamamoto T., Shimono T., Ichiyama T., Taoka T., Sohma O., Yoshikawa H., Kohno Y.

Neurology Vol. 63 ( 10 ) page： 1854 - 1858 2004.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Neurology

Objective: To clarify whether patients with clinical diagnoses of encephalitis/encephalopathy with a reversible lesion in the splenium of the corpus callosum (SCC) share common clinical features. Methods: Possible encephalitis/ encephalopathy patients; with a reversible isolated SCC lesion on MRI were collected retrospectively. Their clinical, laboratory, and radiologic data were reviewed. Results: Fifteen encephalitis/encephalopathy patients with a reversible isolated SCC lesion were identified among 22 patients referred for this study. All 15 patients had relatively mild clinical courses. Twelve of the 15 patients had disorders of consciousness. Eight patients had seizures, and three of them received antiepileptic drugs. All 15 patients clinically recovered completely within 1 month (8 patients within a week) after the onset of neurologic symptoms. The SCC lesion was ovoid in six patients; it extended irregularly from the center to the lateral portion of SCC in the other eight patients. Homogeneously reduced diffusion was seen in all seven patients who underwent diffusion-weighted imaging. There was no enhancement in the five patients so examined. The SCC lesion had completely disappeared in all patients at follow-up MRI exams between 3 days and 2 months after the initial MRI (within 1 week in eight patients). Conclusion: The clinical features among the affected patients were nearly identical, consisting of relatively mild CNS manifestations and complete recovery within 1 month.

DOI： 10.1212/01.WNL.0000144274.12174.CB

Paradoxical parasellar high signals resembling shunt diseases on routine 3D time-of-flight MR angiography of the brain: mechanism for the signals and differential diagnosis from shunt diseases International journal

M Sakamoto, T Taoka, S Iwasaki, H Nakagawa, A Fukusumi, K Takayama, T Wada, K Kichikawa

MAGNETIC RESONANCE IMAGING Vol. 22 ( 9 ) page： 1289 - 93 2004.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Background and Purpose: We occasionally encounter phenomena in which venous flow signals of the cavernous sinus (CS) and/or inferior petrosal sinus (IPS) are visualized paradoxically in patients without arteriovenous shunt in 3D time-of-flight magnetic resonance angiography (3D-TOF MRA) of the brain, The aims of this study are to examine the frequency and cause of this phenomenon ("pseudo-shunt" image) and to determine points of differentiation from definite arteriovenous shunt images ("real shunt").
Methods: We retrospectively examined 85 maximum intensity projection images obtained by MRA in the absence of arteriovenous shunts to detect pseudo-shunt images, and evaluated source images: of pseudo-shunt studies for venous structures. Four real-shunt MRA studies were compared with pseudo-shunt studies on three points: (1) extension of sinuses, (2) extension of cortical veins, and (3) signal intensity of sinuses as assessed by the scoring method (1 point when these findings exist, 0 when they do not).
Results: We detected five CS (3%) and six IPS (4%) signals in 9 (11%) of the 85 cases. In the source images of four pseudo-shunt images in the CS, we detected signals from the sphenoparietal sinus (SPS). The average score was significantly lower in the pseudo-shunt (0.22) than the real-shunt (2.75) images (P<.0001).
Conclusion: In cerebral 3D-TOF MRA, pseudo-shunt images were seen in 11% (9/85) of the study population, with antegrade upward blood flow of the SPS considered as one of the causes. Real-shunt signals can be distinguished from pseudo-shunt signals by evaluation of source images. (C) 2004 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.mri.2004.08.004

Clinically mild encephalitis/encephalopathy with a reversible splenial lesion Reviewed

H Tada, J Takanashi, AJ Barkovich, H Oba, M Maeda, H Tsukahara, M Suzuki, T Yamamoto, T Shimono, T Ichiyama, T Taoka, O Sohma, H Yoshikawa, Y Kohno

NEUROLOGY Vol. 63 ( 10 ) page： 1854 - 1858 2004.11

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Objective: To clarify whether patients with clinical diagnoses of encephalitis/encephalopathy with a reversible lesion in the splenium of the corpus callosum (SCC) share common clinical features. Methods: Possible encephalitis/encephalopathy patients with a reversible isolated SCC lesion on MRI were collected retrospectively. Their clinical, laboratory, and radiologic data were reviewed. Results: Fifteen encephalitis/encephalopathy patients with a reversible isolated SCC lesion were identified among 22 patients referred for this study. All 15 patients had relatively mild clinical courses. Twelve of the 15 patients had disorders of consciousness. Eight patients had seizures, and three of them received antiepileptic drugs. All 15 patients clinically recovered completely within 1 month ( 8 patients within a week) after the onset of neurologic symptoms. The SCC lesion was ovoid in six patients; it extended irregularly from the center to the lateral portion of SCC in the other eight patients. Homogeneously reduced diffusion was seen in all seven patients who underwent diffusion-weighted imaging. There was no enhancement in the five patients so examined. The SCC lesion had completely disappeared in all patients at follow-up MRI exams between 3 days and 2 months after the initial MRI ( within 1 week in eight patients). Conclusion: The clinical features among the affected patients were nearly identical, consisting of relatively mild CNS manifestations and complete recovery within 1 month.

Retinotopy with coordinates of lateral occipital cortex in humans International journal

T Kaido, T Hoshida, T Taoka, T Sakaki

JOURNAL OF NEUROSURGERY Vol. 101 ( 1 ) page： 114 - 8 2004.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC NEUROLOGICAL SURGEONS

Object. The lateral occipital cortex in humans is known as the "extrastriate visual cortex." It is, however, an unexplored field of research, and the anatomical nomenclature for its surface has still not been standardized. This study was designed to investigate whether the lateral occipital cortex in humans has retinotopic representation.
Methods. Four right-handed patients with a diagnosis of intractable epilepsy from space-occupying lesions in the occipital lobe or epilepsy originating in the occipital lobe received permanently implanted subdural electrodes. Electrical cortical stimulation was applied directly applied to the brain through metal electrodes by using a biphasic stimulator. The location of each electrode was measured on a lateral skull x-ray study. Each patient considered a whiteboard with vertical and horizontal median lines. The patient was asked to look at the midpoint on the whiteboard. If a visual hallucination or illusion occurred, the patient recorded its outline, shape, color, location, and motion on white paper one tenth the size of, and with vertical and horizontal median lines similar to those on, the whiteboard. Polar angles and eccentricities of the midpoints of the phosphenes from the coordinate origin were measured on the paper. On stimulation of the lateral occipital lobe, 44 phosphenes occurred. All phosphenes were circular or dotted, with a diameter of approximately I cm, except one that was like a curtain in the peripheral end of the upper and lower visual fields on stimulation of the parietooccipital region. All phosphenes appeared in the visual field contralateral to the cerebral hemisphere stimulated. On stimulation of the lateral occipital lobe, 22 phosphenes moved centrifugally or toward a horizontal line. From three-dimensional scatterplots and contour maps of the polar angles and eccentricities in relation to the x-ray coordinates of the electrodes, one can infer that the lateral occipital cortex in humans has retinotopic representation.
Conclusions. The authors found that phosphenes induced by electrical cortical stimulation of the lateral occipital cortex represent retinotopy. From these results one can assert that visual field representation with retinotopic relation exists in the extrastriate visual cortex.

DOI： 10.3171/jns.2004.101.1.0114

Progressive MRI changes indicating inflammatory neurodegeneration with cognitive decline induced by ischemic stress Reviewed

M Fujinka, T Taoka, Y Matsuo, M Mishima, K Ogoshi, Y Kondo, Asano, I, M Fujiwara, T Sakaki, A Miyasaki, D Park, BK Siesjo

STROKE Vol. 35 ( 6 ) page： E323 - E323 2004.6

Distinguishing between anterior cerebral artery and middle cerebral artery perfusion by color-coded perfusion direction mapping with arterial spin labeling International journal

T Taoka, S Iwasaki, H Nakagawa, A Fukusumi, S Hirohashi, M Sakamoto, K Kichikawa, K Murata

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 25 ( 2 ) page： 248 - 51 2004.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

The purpose of this study was to evaluate collateral circulation by describing anterior cerebral artery and middle cerebral artery perfusion areas. Pairs of image sets spin labeled on the medial and lateral side were used. A pixel-by-pixel t test was performed, with blue gradation used to display lateral perfusion (ie, middle cerebral artery) and orange gradation for anterior cerebral artery perfusion. Extensions of anterior cerebral artery perfusion areas in cases of middle cerebral artery stenosis were described. This method may aid in estimation of collateral circulation for stroke treatment.

Signal characteristics of FLAIR related to water content: comparison with conventional spin echo imaging in infarcted rat brain International journal

T Taoka, M Fujioka, Y Matsuo, M Notoya, S Iwasaki, A Fukusumi, H Nakagawa, M Sakamoto, K Kichikawa, H Ohishi

MAGNETIC RESONANCE IMAGING Vol. 22 ( 2 ) page： 221 - 7 2004.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

To examine the correlation between tissue water content and signal intensity on fluid-attenuated inversion recovery (FLAIR) images, we analyzed infarcted rat brain, verified the results by theoretical simulation, and compared them with conventional spin-echo images. We produced brain infarction with cavitation in five rats by middle cerebral artery occlusion. After in vivo MRI, histologic sections of the MRI plane were obtained. We measured the signal intensity of regions on FLAIR and spin-echo images, and measured the area of cavitation on histologic sections. We plotted curves of cavity percentage to signal intensity. Theoretical values were calculated using a two- compartment model. On the curve of cavity area to signal intensity, the signal on FLAIR images peaked in tissues with 20% to 30% area of cavitation. On the theoretical curve, the signal on FLAIR images peaked at 90% tissue water content. These results seem to be characteristic of FLAIR. (C) 2004 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.mri.2003.09.004

Distinguishing between anterior cerebral artery and middle cerebral artery perfusion by color-coded perfusion direction mapping with arterial spin labeling Reviewed

T Taoka, S Iwasaki, H Nakagawa, A Fukusumi, S Hirohashi, M Sakamoto, K Kichikawa, K Murata

AMERICAN JOURNAL OF NEURORADIOLOGY Vol. 25 ( 2 ) page： 248 - 251 2004.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC NEURORADIOLOGY

Distinguishing between Anterior Cerebral Artery and Middle Cerebral Artery Perfusion by Color-Coded Perfusion Direction Mapping with Arterial Spin Labeling

Taoka T., Iwasaki S., Nakagawa H., Fukusumi A., Hirohashi S., Sakamoto M., Kichikawa K., Murata K.

American Journal of Neuroradiology Vol. 25 ( 2 ) page： 248 - 251 2004.2

Language：English Publishing type：Research paper (scientific journal) Publisher：American Journal of Neuroradiology

Imaging and management of acute stroke Reviewed

WC Yuh, T Taoka, T Ueda, M Maeda

DISEASES OF THE BRAIN, HEAD AND NECK, SPINE page： 20 - 26 2004

Optic Tractography in Epilepsy Surgery Reviewed

Toshiaki Taoka, Tohru Hoshida, Kimihiko Kichikawa, Toshisuke Sakaki

Nosotchu Vol. 26 ( 4 ) page： 574 - 578 2004

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Stroke Society

Diffusion tensor tractography is a newly developed method for tracing tracts in white matter using combination of diffusion tensor images. We evaluate the degree of impairment of optic tracts in the cases with visual field defect after temporal lobectomy using diffusion tensor tractography. We examined 8 cases after temporal lobectomy for temporal lobe epilepsy. Visual field defect in medial sector and lateral sector of upper 1/4 visual field were evaluated. Diffusion tensor tractography of optic radiation was made from 6 axes diffusion tensor images. We evaluated the correlation between the degree of visual field defect and visualization of Meyer's loop on tractographies. Medial sector field tends to be impaired after temporallobectomy. Diffusion tensor tractography showed incomplete to no visualization of Meyer's loop in the cases with severe visual field defect. While, visualization of optic radiation was almost complete in cases with mild visual field defect. Diffusion tensor tractography was useful in evaluating post surgical changes in optic radiation. Potential usefulness of tractography in surgical planning was also suggested.

DOI： 10.3995/jstroke.26.574

Magnetic resonance imaging shows delayed ischemic striatal neurodegeneration

M Fujioka, T Taoka, Y Matsuo, K Mishima, K Ogoshi, Y Kondo, M Tsuda, M Fujiwara, T Asano, T Sakaki, A Miyasaki, D Park, BK Siesjo

ANNALS OF NEUROLOGY Vol. 54 ( 6 ) page： 732 - 47 2003.12

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-LISS

Brief focal ischemia leading to temporary neurological deficits induces delayed hyperintensity on T1-weighted magnetic resonance imaging (MRI) in the striatum of humans and rats. The T1 hyperintensity may stem from biochemical alterations including manganese (Mn) accumulation after ischemia. To clarify the significance of this MRI modification, we investigated the changes in the dorsolateral striatum of rats from 4 hours through 16 weeks after a 15-minute period of middle cerebral artery occlusion (MCAO), for MRI changes, Mn concentration, neuronal number, reactivities of astrocytes and microglia/macrophages, mitochondrial Mn-superoxide dismutase (Mn-SOD), glutamine synthetase (GS), and amyloid precursor protein. The cognitive and behavioral studies were performed in patients and rats and compared with striatal T1 hyperintensity to show whether alteration in brain function correlated with MRI and histological changes. The T1-weighted MRI signal intensity of the dorsolateral striatum increased from 5 days to 4 weeks after 15-minute MCAO, and subsequently decreased until 16 weeks. The Mn concentration of the dorsolateral striatum increased after ischemia in concert with induction of Mn-SOD and GS in reactive astrocytes. The neuronal survival ratio in the dorsolateral. striatum decreased significantly from 4 hours through 16 weeks, accompanied by extracellular amyloid precursor protein accumulation and chronic glial/inflammatory responses. The patients and rats with neuroradiological striatal degeneration had late-onset cognitive and/or behavioral declines after brief focal ischemia. This study suggests that (1) the hyperintensity on T1-weighted MRI after mild ischemia may involve tissue Mn accumulation accompanied by Mn-SOD and GS induction in reactive astrocytes, (2) the MRI changes correspond to striatal neurodegeneration with a chronic inflammatory response and signs of oxidative stress, and (3) the subjects with these MRI changes are at risk for showing a late impairment of brain function even though the transient ischemia is followed by total neurological recovery.

DOI： 10.1002/ana.10751

Vasogenic edema and VEGF expression in a rat two-vein occlusion model.

Kimura R, Nakase H, Sakaki T, Taoka T, Tsuji T

Acta neurochirurgica. Supplement Vol. 86 page： 213 - 7 2003

Progressive MRI change indicates manganese accumulation and striatal neurodegeneration resulting in cognitive decline in humans and rats after brief focal ischemia.

Fujioka M, Taoka T, Matsuo Y, Mishima K, Ogoshi K, Kondo Y, Tsuda M, Fujiwara M, Asano T, Sasaki T, Miyasaki A, Park D, Siesj, BK

Ann Neurol Vol. 54 page： 732 - 747 2003

Vasogenic edema and VEGF expression in a rat two-vein occlusion model Reviewed

R Kimura, H Nakase, T Sakaki, T Taoka, T Tsuji

BRAIN EDEMA XII Vol. 86 page： 213 - 217 2003

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPRINGER-VERLAG WIEN

Vasogenic edema plays an important etiologic role in the pathogenesis of cerebral venous circulation disturbances (CVCDs). Since vascular endothelial growth factor (VEGF) is a major mediator in angiogenesis and vascular permeability, including induction of vasogenic edema, the present study was undertaken to investigate whether it has any relevance to CVCDs.
Male Wistar rats (n = 15) were used. Two adjacent cortical veins were occluded photochemically using rose bengal dye and fiberoptic illumination, with evaluation 24 hours thereafter by magnetic resonance imaging (MRI). Each brain was removed from the skull Immediately after MRI and processed for hematoxylin-eosin staining (H&E staining) of sections for histopathology and comparison with MRI data. VEGF expression as demonstrated immunohistochemically appeared to coincide with vasogenic edema, diagnosed as high intensity areas on apparent diffusion coefficient of water (ADCw) maps. On the basis of these data, we conclude that VEGF is related to formation of vasogenic edema in the acute stage of CVCD.

排尿日誌を利用してスクリーニングした夜間多尿例における視床下部・下垂体後葉機能の検討

夏目修, 穴井洋, 田岡俊昭

日本泌尿器科学会雑誌 Vol. 94 ( 2 ) page： 136 2003

Vasogenic edema and VEGF expression in a rat two-vein occlusion model

Kimura R., Nakase H., Sakaki T., Taoka T., Tsuji T.

Acta Neurochirurgica, Supplementum ( 86 ) page： 213 - 217 2003

Language：English Publishing type：Research paper (scientific journal) Publisher：Acta Neurochirurgica, Supplementum

Vasogenic edema plays an important etiologic role in the pathogenesis of cerebral venous circulation disturbances (CVCDs). Since vascular endothelial growth factor (VEGF) is a major mediator in angiogenesis and vascular permeability, including induction of vasogenic edema, the present study was undertaken to investigate whether it has any relevance to CVCDs. Male Wistar rats (n = 15) were used. Two adjacent cortical veins were occluded photochemically using rose bengal dye and fiberoptic illumination, with evaluation 24 hours thereafter by magnetic resonance imaging (MRI). Each brain was removed from the skull immediately after MRI and processed for hematoxylin-eosin staining (H&E staining) of sections for histopathology and comparison with MRI data. VEGF expression as demonstrated immunohistochemically appeared to coincide with vasogenic edema, diagnosed as high intensity areas on apparent diffusion coefficient of water (ADCw) maps. On the basis of these data, we conclude that VEGF is related to formation of vasogenic edema in the acute stage of CVCD. © Springer-Verlag 2003.

DOI： 10.1007/978-3-7091-0651-8_46

[Evaluation of appearance with high-speed CE-3dMRDSA in brain].

Doi T, Nogi A, Taoka T, Hirohashi S

Nihon Hoshasen Gijutsu Gakkai zasshi Vol. 58 ( 12 ) page： 1615 - 21 2002.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Radiological Technology

We evaluated the fitting scan technique for CE-3dMRDSA, and found common ground that determines spatial resolution and time resolution (slab thickness and partition number). We also examined the relation between appearance and time resolution (volume of contrast medium and injection speed). To obtain good image contrast, the volume of contrast medium needs to be at least 7 ml and suitable for an injection speed of 3-5 ml/sec. However, when we increased the volume of contrast medium and decreased injection speed, changes in MRDSA images with time became worse. The measure of the bolus with contrast medium was found to determine image contrast. When contrast medium is injected earlier, it circulates earlier within the brain. If the scan time is not short enough, it is not possible to observe changes in MRDSA images. And when spatial resolution is improved, time resolution becomes worse. Therefore, it is important to find the point of compromise between spatial resolution and time resolution. If we look for anterior MIP images, the CNR in the spatial resolusion didn't change, when the slice thickness is more than 3 mm. Because, the partial volume effect decide the image contrast. However, unless the view is from the front, slice thickness influences spatial resolution. Therefore, when we view MIP images from the lateral direction, slice thickness must be set at less than 2 mm. Results indicated that, in CE-3dMRDSA with the fitting technique, slice thickness should be less than 3 mm, partition number 16-20, slab thickness 48 mm, contrast medium volume 7-10 ml, and injection speed 3-5 ml.

DOI： 10.6009/jjrt.kj00000921540

Method and timing of tumor volume measurement for outcome prediction in cervical cancer using magnetic resonance Imaging Reviewed

CiNii Books

Method and timing of tumor volume measurement for outcome prediction in cervical cancer using magnetic resonance imaging.

Mayr NA, Taoka T, Yuh WT, Denning LM, Zhen WK, Paulino AC, Gaston RC, Sorosky JI, Meeks SL, Walker JL, Mannel RS, Buatti JM

International journal of radiation oncology, biology, physics Vol. 52 ( 1 ) page： 14-22 2002.1

NA Mayr, T Taoka, WTC Yuh, LM Denning, WNK Zhen, AC Paulino, RC Gaston, JI Sorosky, SL Meeks, JL Walker, RS Mannel, JM Buatti

INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Vol. 52 ( 1 ) page： 14 - 22 2002.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Purpose: Recently, imaging-based tumor volume before, during, and after radiation therapy (RT) has been shown to predict tumor response in cervical cancer. However, the effectiveness of different methods and timing of imaging-based tumor size assessment have not been investigated. The purpose of this study was to compare the predictive value for treatment outcome derived from simple diameter-based ellipsoid tumor volume measurement using orthogonal diameters (with ellipsoid computation) with that derived from more complex contour tracing/region-of-interest (ROI) analysis 3D tumor volumetry.
Methods and Materials: Serial magnetic resonance imaging (MRI) examinations were prospectively performed in 60 patients with advanced cervical cancer (Stages IB2-IVB/recurrent) at the start of RT, during early RT (20-25 Gy), mid-RT (45-50 Gy), and at follow-up (1-2 months after RT completion). ROI-based volumetry was derived by tracing the entire tumor region in each MR slice on the computer work station. For the diameter-based surrogate "ellipsoid volume," the three orthogonal diameters (d(1), d(2), d(3)) were measured on film hard copies to calculate volume as an ellipsoid (d(1) x d(2) x d(3) x pi/6). Serial tumor volumes and regression rates determined by each method were correlated with local control, disease-free and overall survival, and the results were compared between the two measuring methods. Median post-therapy follow-up was 4.9 years (range, 2.0-8.2 years).
Results: The best method and time point of tumor size measurement for the prediction of outcome was the tumor regression rate in the mid-therapy MRI examination (at 45-50 Gy) using 3D ROI volumetry. For the pre-RT measurement both the diameter-based method and ROI volumetry provided similar predictive accuracy, particularly for patients with small (<40 cm(3)) and large ( &GE;100 cm(3)) pre-RT tumor size. However, the pre-RT tumor size measured by either method had much less predictive value for the intermediate-size (40-99 cm(3)) tumors, which accounted for the majority of patients (55%). Tumor regression rate (fast vs. slow) obtained during mid-RT (45-50 Gy), which could only be appreciated by 3D ROI volumetry, had the best outcome prediction rate for local control (84% vs. 22%, p < 0.0001) and disease-free survival (63% vs. 20%, p = 0.0005). Within the difficult to classify intermediate pre-RT size group, slow ROI-based regression rate predicted all treatment failures (local control rate: 0% vs. 91%,p < 0.0001; disease-free survival: 0% vs. 73%, p < 0.0001). Mid-RT regression rate based on simple diameter measurement did not predict outcome. The early-RT and post-RT measurements were least useful with either measuring method.
Conclusion: Our preliminary data suggest that for the prediction of treatment outcome in cervical cancer, initial tumor volume can be estimated by simple diameter-based measurement obtained from film hard copies. When initial tumor volume is in the intermediate size range, ROI volumetry and an additional MRI during RT are needed to quantitatively analyze tumor regression rate for the prediction of treatment outcome. (C) 2002 Elsevier Science Inc.

DOI： 10.1016/S0360-3016(01)01808-9

Palmaz stent deployment for subclavian and brachiocephalic arterial occlusive disease. Factors predictive of restenosis.

Nakagawa H, Kichikawa K, Takayama K, Sakamoto M, Wada T, Taoka T, Fukusumi A, Iwasaki S, Uchida H, Sakaki T

Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences Vol. 7 ( Suppl 1 ) page： 49 - 52 2001.12

Detection of early venous filling in gliomas on MRI: Preliminary study by 2D time-resolved dynamic contrast-enhanced MR angiography with echo-sharing technique

Sakamoto M., Taoka T., Iwasaki S., Fukusumi A., Nakagawa H., Hirohashi S., Takayama K., Wada T., Kichikawa K., Uchida H., Ohishi H., Murata K., Okamoto J.

Magnetic Resonance Imaging Vol. 19 ( 9 ) page： 1193 - 1201 2001.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Magnetic Resonance Imaging

We evaluated the detection of early venous filling of gliomas by 2D time resolved dynamic contrast enhanced MR digital subtraction angiography (MR-DSA) with echo-sharing technique and compared the results with those of conventional contrast digital subtraction angiography (C-DSA). C-DSA and MR-DSA examinations were performed in eight patients with malignant gliomas and compared with regard to the visualization of early filling veins; time intensity curves of arteries, early filling veins and normal veins were made, and rise time and time to peak were evaluated. MR-DSA visualized 12 out of 17 early filling veins depicted on C-DSA. The failure of five veins to be depicted may be due to the overlapping of other structures, such as other vessels and tumor stain. On time intensity curves, the mean difference in rise time was 0.9 sec between the artery and early filling vein, and the mean difference of time to peak was 1.6 sec. C-DSA has been the modality of choice in demonstrating early venous filling, a useful finding in the differential diagnosis of gliomas. However the high temporal resolution of MR-DSA with echo-sharing technique provides sufficient visualization of early venous filling of gliomas. Additional information for precise differential diagnosis may be obtained by adding MR-DSA to the imaging protocol for gliomas. © 2001 Elsevier Science Inc. All rights reserved.

DOI： 10.1016/S0730-725X(01)00450-7

Palmaz Stent deployment for subclavian and brachiocephalic arterial occlusive disease - Factors predictive of restenosis Reviewed

H Nakagawa, K Kichikawa, K Takayama, M Sakamoto, T Wada, T Taoka, A Fukusumi, S Iwasaki, H Uchida, T Sakaki

INTERVENTIONAL NEURORADIOLOGY Vol. 7 page： 49 - 52 2001.12

Language：English Publishing type：Research paper (scientific journal) Publisher：EDIZIONI CENTAURO

Palmaz stent deployment is a useful method for subclavian and brachiocephalic arterial occlusive disease. We evaluated restenosis or intimal thickening after Palmaz stent deployment for nine lesions of subclavian or brachiocephalic arterial occlusive disease focusing on stent diameter, atheroma thickness near the stent, and degree of coverage for the lesion. Follow up DSA and IVUS at 5-14 months (mean 9) after therapy showed no significant changes in the size or shape of the stent itself There were two lesions of thin in-stent intimal hyperplasia and five lesions of thick hyperplasia.
There was no close relationship between intimal hyperplasia and stent diameter or atheroma size (relative thickness). There was some relationship between the degree of coverage of the lesion by the stent and degree of intimal hyperplasia, but to determine statistical significance, accumulation of a greater number of cases is necessary.

Detection of early venous filling in gliomas on MRI: preliminary study by 2D time-resolved dynamic contrast-enhanced MR angiography with echo-sharing technique.

Sakamoto M, Taoka T, Iwasaki S, Fukusumi A, Nakagawa H, Hirohashi S, Takayama K, Wada T, Kichikawa K, Uchida H, Ohishi H, Murata K, Okamoto J

Magnetic resonance imaging Vol. 19 ( 9 ) page： 1193 - 201 2001.11

Detection of early venous filling in gliomas on MRI: Preliminary Study by 2D time-resolved dynamic contrast-enhanced MR angiography with echo-sharing technique Reviewed

M Sakamoto, T Taoka, S Iwasaki, A Fukusumi, H Nakagawa, S Hirohashi, K Takayama, T Wada, K Kichikawa, H Uchida, H Ohishi, K Murata

MAGNETIC RESONANCE IMAGING Vol. 19 ( 9 ) page： 1193 - 1201 2001.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

DOI： 10.1016/S0730-725X(01)00450-7

Factors influencing visualization of vertebral metastases on MR imaging versus bone scintigraphy Reviewed

T Taoka, NA Mayr, HJ Lee, WTC Yuh, TM Simonson, K Rezai, KS Berbaum

AMERICAN JOURNAL OF ROENTGENOLOGY Vol. 176 ( 6 ) page： 1525 - 1530 2001.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ROENTGEN RAY SOC

OBJECTIVE. The purpose of this study was to investigate whether the location and size of vertebral body metastases influence the difference in detection rates between MR imaging and bone scintigraphy.
MATERIALS AND METHODS. We retrospectively evaluated the vertebral body lesions detected on MR imaging in 74 patients with known widely disseminated metastatic disease. Three radiologists independently reviewed the MR images and bone scintigraphs. MR imaging findings included lesion size and its spatial relationship to the bony cortex (intramedullary, subcortical, and transcortical) and results were correlated with those of planar technetium 99m bone scintigraphy.
RESULTS. Findings on bone scans were negative for all intramedullary lesions without cortical involvement shown on MR imaging, regardless of their size. Findings on bone scans (71.3% for transcortical and 33.8% for subcortical) were frequently positive for lesions with cortical involvement (trans- or subcortical), and the probability of positive findings on bone scans was also influenced by the lesion size. Statistical analysis showed a positive correlation among cortical involvement, lesion size, and positive findings on bone scintigraphy (p < 0.0001).
CONCLUSION. Location (the presence of cortical bone involvement on MR imaging) and size of the vertebral body metastases appear to be important contributing factors to the difference in detection rates between MR imaging and bone scintigraphy. Cortical involvement is likely the cause of positive findings on bone scans. Early vertebral metastases tend to be small and located in the medullary cavity without cortical involvement, and therefore, findings may be positive on MR images but negative on bone scans.

DOI： 10.2214/ajr.176.6.1761525

Sulcal hyperintensity on fluid-attenuated inversion recovery MR images in patients without apparent cerebrospinal fluid abnormality Reviewed

T Taoka, WTC Yuh, ML White, JP Quets, JE Maley, T Ueda

AMERICAN JOURNAL OF ROENTGENOLOGY Vol. 176 ( 2 ) page： 519 - 524 2001.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ROENTGEN RAY SOC

OBJECTIVE. Failure to suppress cerebrospinal fluid (CSF) signal intensity (sulcal hyperintensity) on fluid-attenuated inversion recovery (FLAIR) images has been reported in patients with abnormal CSF such as those with meningitis and subarachnoid hemorrhage. Our study investigates the clinical history and MR findings associated with sulcal hyperintensity on FLAIR images in patients without apparent CSF abnormality.
SUBJECTS AND METHODS. Three hundred consecutive MR imaging examinations were prospectively screened for patients with sulcal hyperintensity on FLAIR images. Nine patients with clinical, CT, or laboratory evidence suggesting abnormal CSF were excluded. The distribution of sulcal hyperintensity on FLAIR images and associated abnormal enhance ment were evaluated, The presence of the "dirty CSF" sign (mild increase in CSF signal on unenhanced T1-weighted images or mild decrease on T2-weighted images) in the corresponding hyperintense sulcus was also assessed.
RESULTS. Twenty-six (8.9%) of the 291 patients had sulcal hyperintensity (16 focal. 10 diffuse) associated with 18 masses (6.1%) and eight vascular abnormalities (2.7%). Sulcal hy perintensity was frequently associated with the dirty CSF sign (69.2%) and abnormal contrast enhancement (overall, 96.2%; 88.5%, leptomeningeal; 53.8%, vascular enhancement).
CONCLUSION. Our study shows that sulcal hyperintensity on FLAIR imaging can occur in patients without apparent CSF abnormality. Its frequent association with mass effect, vascular disease, abnormal vascular enhancement, and dirty CSF sign suggests that an increase in blood pool, a small amount of protein leakage, and the "flow-entering" phenomenon of the congested blood may contribute to sulcal hyperintensity on FLAIR images.

DOI： 10.2214/ajr.176.2.1760519

Sulcal hyperintensity on fluid-attenuated inversion recovery MR images in patients without apparent cerebrospinal fluid abnormality Reviewed

T Taoka, WTC Yuh, ML White, JP Quets, JE Maley, T Ueda

AMERICAN JOURNAL OF ROENTGENOLOGY Vol. 176 ( 2 ) page： 519 - 524 2001.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ROENTGEN RAY SOC

Chronic brain inflammation results in progressive MRI change and dementia in ischemic neurodegeneration Reviewed

Fujioka M, Taoka T, Matsuo Y, Mishima K, Fujiwara M, Ogoshi K, Kondo Y, Sakaki T, Park D, Siesjo B. K

Society for Neuroscience Abstracts Vol. 27 ( 2 ) page： 2304 2001

Palmaz stent deployment for subclavian and brachiocephalic arterial occlusive disease: Factors predictive of restenosis

Nakagawa H., Kichikawa K., Takayama K., Sakamoto M., Wada T., Taoka T., Fukusumi A., Iwasaki S., Uchida H., Sakaki T.

Interventional Neuroradiology Vol. 7 ( SUPPL. 1 ) page： 49 - 52 2001

Language：English Publishing type：Research paper (scientific journal) Publisher：Interventional Neuroradiology

Palmaz stent deployment is a useful method for subclavian and brachiocephalic arterial occlusive disease. We evaluated restenosis or intimal thickening after Palmaz stent deployment for nine lesions of subclavian or brachiocephalic arterial occlusive disease focusing on stent diameter, atheroma thickness near the stent, and degree of coverage for the lesion. Follow up DSA and IVUS at 5-14 months (mean 9) after therapy showed no significant changes in the size or shape of the stent itself. There were two lesions of thin in-stent intimal hyperplasia and five lesions of thick hyperplasia. There was no close relationship between intimal hyperplasia and stent diameter or atheroma size (relative thickness). There was some relationship between the degree of coverage of the lesion by the stent and degree of intimal hyperplasia, but to determine statistical significance, accumulation of a greater number of cases is necessary.

MR imaging of pituitary morphology in idiopathic intracranial hypertension.

Yuh WT, Zhu M, Taoka T, Quets JP, Maley JE, Muhonen MG, Schuster ME, Kardon RH

Journal of magnetic resonance imaging : JMRI Vol. 12 ( 6 ) page： 808-13 2000.12

MR imaging of pituitary morphology in idiopathic intracranial hypertension Reviewed

WTC Yuh, MW Zhu, T Taoka, JP Quets, JE Maley, MG Muhonen, ME Schuster, RH Kardon

JOURNAL OF MAGNETIC RESONANCE IMAGING Vol. 12 ( 6 ) page： 808 - 813 2000.12

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN WILEY & SONS INC

The aim of this study was to investigate the morphologic changes of the pituitary gland in patients with the clinical diagnosis of idiopathic intracranial hypertension (IIH). Qualitative and quantitative analyses of pituitary morphology were performed in normal subjects (n = 23), patients with the clinical diagnosis of IIH (n = 40), and patients with acute increased intracranial pressure (AICP; n = 37) caused by acute head trauma. The loss of pituitary height (concavity) on the sagittal T1-weighted image was classified into five categories: I = normal, II = superior concavity that was mild (< (1)/(3) the height of the sella), III = moderate (between (1)/(3) and (2)/(3) concavity of height of sells), IV = severe (> (2)/(3) concavity of height of sells), and V = empty sells. The area ratio of pituitary gland to sella turcica measured in the midsagittal plane was quantified. Clinical records were retrospectively reviewed to correlate with magnetic resonance (MR) findings. Using moderate concavity (> (1)/(3)) as the minimum criterion for abnormality, IIH patients had an 85% incidence of morphologic changes with 80% sensitivity and 92% specificity. Empty sells (almost complete concavity of the sella) was found in only 2.5% of patients with IIH. Quantitative analysis of the pituitary gland/sella turcica area ratio showed a significant decrease in patients with IIH (P < 0.0001) but no significant difference between the normal subjects and AICP patients. A posterior deviation of the pituitary stalk was seen in 43% of patients. No enlargement of the ventricles or sulcal effacement was seen in IIH patients. Routine brain MR examination of patients with IIH frequently shows morphologic changes of the pituitary gland ranging from various degrees of concavity to (rarely) the extreme case of an empty sella. The etiology is unknown and may be related to the severity and duration of elevated CSF pressure. Such findings may be useful to facilitate the diagnosis of IIH, particularly in patients with equivocal clinical findings or when IIH is not suspected. (C) 2000 Wiley-Liss, Inc.

DOI： 10.1002/1522-2586(200012)12:6<808::AID-JMRI3>3.0.CO;2-N

DOI： 10.1002/1522-2586(200012)12:6<808::aid-jmri3>3.0.co;2-n

Magnetic resonance imaging in the assessment of radiation response in cervical cancer: Regarding Hatano K et al. IJROBP 1999;45 : 339-344. Reviewed

Magnetic resonance imaging in the assessment of radiation response in cervical cancer: regarding Hatano K et al. IJROBP 1999; 45:399-344.

Mayr NA, Taoka T, Yuh WT, Zhen WK, Paulino AC, Sorosky JI, Buatti JM

International journal of radiation oncology, biology, physics Vol. 48 ( 3 ) page： 910-2 2000.10

NA Mayr, T Taoka, WTC Yuh, WNK Zhen, AC Paulino, JI Sorosky, JM Buatti

INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Vol. 48 ( 3 ) page： 910 - 911 2000.10

Functional magnetic resonance imaging using iron oxide particles in characterizing head and neck adenopathy.

Hoffman HT, Quets J, Toshiaki T, Funk GF, McCulloch TM, Graham SM, Robinson RA, Schuster ME, Yuh WT

The Laryngoscope Vol. 110 ( 9 ) page： 1425-30 2000.9

Enhancement pattern of normal extraocular muscles in dynamic contrast-enhanced MR imaging with fat suppression.

Taoka T, Iwasaki S, Uchida H, Fukusumi A, Kichikawa K, Nakagawa H, Takayama K, Sakamoto M, Ohishi H

Acta radiologica (Stockholm, Sweden : 1987) Vol. 41 ( 3 ) page： 211 - 6 2000.5

Enhancement pattern of normal extraocular muscles in dynamic contrast-enhanced MR imaging with fat suppression Reviewed

T Taoka, S Iwasaki, H Uchida, A Fukusumi, K Kichikawa, H Nakagawa, K Takayama, M Sakamoto, H Ohishi

ACTA RADIOLOGICA Vol. 41 ( 3 ) page： 211 - 216 2000.5

Language：English Publishing type：Research paper (scientific journal) Publisher：MUNKSGAARD INT PUBL LTD

Purpose. To evaluate the internal structure of normal extraocular muscles on fat-suppressed dynamic contrast-enhanced MR imaging.
Material and Methods. Ten subjects were examined using fat-suppressed dynamic contrast-enhanced MR imaging. We evaluated the enhancement pattern (C-shaped or ring-like) of extraocular muscles and quantified the maximum ratios of enhancement (R-max) and maximum ratios of signal increase (V-max). We also quantified R-max and V-max in the central and peripheral portions of medial rectus muscles.
Results: in the early phase of dynamic contrast-enhanced MR imaging, a C-shaped or ring-like pattern was observed in 100% of inferior rectus, 95% of medial rectus, 55% of superior rectus, 20% of lateral rectus, and 15% of superior oblique muscles. Overall mean R-max and V-max values showed statistically significant differences to the temporal muscles. For the peripheral portion of medial rectus muscles, mean R-max and V-max values were greater than for the central portion.
Conclusion: Using fat-suppressed dynamic contrast-enhanced MR imaging, the C-shape or ring-like internal structure of the extraocular muscles could be visualized, and were considered to reflect their structure of orbital and global layers. Potential usefulness of the fat-suppressed dynamic contrast-enhanced MR imaging for detecting pathological status is suggested.

DOI： 10.1080/028418500127345361

Enhancement pattern of normal extraocular muscles in dynamic contrast-enhanced MR imaging with fat suppression

Taoka T., Iwasaki S., Uchida H., Fukusumi A., Kichikawa K., Nakagawa H., Takayama K., Sakamoto M., Ohishi H.

Acta Radiologica Vol. 41 ( 3 ) page： 211 - 216 2000.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Acta Radiologica

Purpose: To evaluate the internal structure of normal extraocular muscles on fat-suppressed dynamic contrast-enhanced MR imaging. Material and Methods: Ten subjects were examined using fat-suppressed dynamic contrast-enhanced MR imaging. We evaluated the enhancement pattern (C-shaped or ring-like) of extraocular muscles and quantified the maximum ratios of enhancement (Rmax) and maximum ratios of signal increase (Vmax). We also quantified Rmax and Vmax in the central and peripheral portions of medial rectus muscles. Results: In the early phase of dynamic contrast-enhanced MR imaging, a C-shaped or ring-like pattern was observed in 100% of inferior rectus, 95% of medial rectus, 55% of superior rectus, 20% of lateral rectus, and 15% of superior oblique muscles. Overall mean Rmax and Vmax values showed statistically significant differences to the temporal muscles. For the peripheral portion of medial rectus muscles, mean Rmax and Vmax values were greater than for the central portion. Conclusion: Using fat-suppressed dynamic contrast-enhanced MR imaging, the C-shape or ring-like internal structure of the extraocular muscles could be visualized, and were considered to reflect their structure of orbital and global layers. Potential usefulness of the fat-suppressed dynamic contrast-enhanced MR imaging for detecting pathological status is suggested.

DOI： 10.1080/028418500127345361

Hippocampal damage in the human brain after cardiac arrest.

Delayed ischemic hyperintensity of T1-weighted MRI Reviewed

M Fujioka, KI Hiramatsu, T Sakaki, T Taoka, S Sakaguchi, Y Matsuo

STROKE Vol. 31 ( 3 ) page： 797 - 798 2000.3

Fujioka M, Nishio K, Miyamoto S, Hiramatsu KI, Sakaki T, Okuchi K, Taoka T, Fujioka S

Cerebrovascular diseases (Basel, Switzerland) Vol. 10 ( 1 ) page： 2 - 7 2000.1

Delayed ischemic hyperintensity on T1 weighted magnetic resonance images and induced manganese superoxide dismutase in mitochondria after mild focal ischemia: Long-lasting oxidative stress hypothesis Reviewed

M Fujioka, T Taoka, Y Matsuo, KI Hiramatsu, Y Kondo, K Ogoshi, A Miyasaki, T Sakaki, K Kato, A Colony, BK Siesjs

STROKE Vol. 31 ( 1 ) page： 341 - 341 2000.1

Hippocampal damage in the human brain after cardiac arrest Reviewed

M Fujioka, K Nishio, S Miyamoto, K Hiramatsu, T Sakaki, K Okuchi, T Taoka, S Fujioka

CEREBROVASCULAR DISEASES Vol. 10 ( 1 ) page： 2 - 7 2000.1

Language：English Publishing type：Research paper (scientific journal) Publisher：KARGER

Background and Purpose: Very few reports are available on changes in the human hippocampus after cardiac arrest. The objective of this study was to investigate if specific hippocampal volume losses can be demonstrated in the human brain following reperfusion after cardiac arrest. Methods: We assessed the volumes of the hippocampal formation (HF) and temporal lobe excluding HF (TL) as the contrast using magnetic resonance (MR)-imaging-based volumetry in 11 vegetative patients after cardiac arrest and in 22 healthy controls of similar age, sex and body size distribution. The measured volumes were normalized for differences in the head size among subjects by dividing by the total intracranial volume (TICV). The MR images of the 11 patients were obtained between days 8 and 21 after cardiac arrest. Results: The observed volumes of HFs and TLs of both patient and control groups were as follows: right HF volume (HFV): 2.67 +/- 0.19 (mean +/- SD, cm(3)) in patients versus 3.89 +/- 0.44 in controls; left HFV: 2.72 +/- 0.17 versus 3.74 +/- 0.35; right TL volume (TLV): 73.37 +/- 6.54 versus 80.08 +/- 7.62, and left TLV: 72.45 +/- 6.77 versus 78.59 +/- 6.68. The normalized indic;es (HFV/TICV and TLV/TICV) were as follows: right HF: 0.0021 +/- 0.0002 (mean +/- SD) in patients versus 0.0031 +/- 0.0001 in controls, p < 0.0001, left HF: 0.0022 +/- 0.0002 versus 0.0030 +/- 0.0001, p < 0.0001, right TL: 0.058 +/- 0.002 versus 0.064 +/- 0.004, p = 0.0007, and left TL: 0.058 +/- 0.002 versus 0.062 +/- 0.004, p = 0.0014. The HFV-TLV ratios (HFV/TICV divided by TLV/TICV) of both groups were: right HFV-TLV ratio: 0.037 +/- 0.004 in patients versus 0.049 +/- 0.004 in controls, p < 0.0001, left HFV-TLV ratio: 0.038 +/- 0.004 versus 0.048 +/- 0.004, p < 0.0001. Conclusions: The patient group had HFs that were 26.8-30.6% smaller than those of the control group, but in the patient group, the TLs slightly decreased in size by only 7.8-8.2% of the volume of those in the control group within 21 days after cardiac arrest. The volume reductions in the bilateral HFs of patients after cardiac arrest were significantly larger than those in the bilateral TLs. We speculate that this specific rapid hippocampal shrinkage reflects its greater vulnerability to global brain ischemia. Copyright (C) 2000 S. Karger AG, Basel.

DOI： 10.1159/000016018