Faculty Profiles - TAOKA Toshiaki

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