研究者詳細 - 田岡　俊昭

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

Reorganization of brain networks and its association with general cognitive performance over the adult lifespan 査読有り国際誌 Open Access

Bagarinao, E; Watanabe, H; Maesawa, S; Mori, D; Hara, K; Kawabata, K; Yoneyama, N; Ohdake, R; Imai, K; Masuda, M; Yokoi, T; Ogura, A; Taoka, T; Koyama, S; Tanabe, HC; Katsuno, M; Wakabayashi, T; Kuzuya, M; Ozaki, N; Hoshiyama, M; Isoda, H; Naganawa, S; Sobue, G

SCIENTIFIC REPORTS 9 巻 ( 1 ) 頁： 11352 - 11352 2019年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Reports

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

Kato, Y; Bokura, K; Taoka, T; Naganawa, S

JAPANESE JOURNAL OF RADIOLOGY 37 巻 ( 5 ) 頁： 431 - 435 2019年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Radiology

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 T 2 -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 (SI mean ) values. Normalized SI (SI norm ) values, defined as the SI mean value of each TR divided by the SI mean value of 9000-ms TR for each concentration were compared. Results: Longer TR increased the SI mean values in all solutions. In the 0.250 mM solution, the SI mean value of 16,000-ms TR was 1.07-times greater than that of 9000-ms TR. In contrast, the SI mean 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 35 巻 ( 13 ) 頁： 120 - 121 2019年4月

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 35 巻 ( 13 ) 頁： 156 - 158 2019年4月

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 35 巻 ( 13 ) 頁： 159 - 161 2019年4月

Can low b value diffusion weighted imaging evaluate the character of cerebrospinal fluid dynamics? 査読有り

Taoka, T; Naganawa, S; Kawai, H; Nakane, T; Murata, K

JAPANESE JOURNAL OF RADIOLOGY 37 巻 ( 2 ) 頁： 135 - 144 2019年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Radiology

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/mm 2 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/mm 2 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

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

Age Dependence of Gadolinium Leakage from the Cortical Veins into the Cerebrospinal Fluid Assessed with Whole Brain 3D-real Inversion Recovery MR Imaging 査読有り Open Access

Naganawa, S; Nakane, T; Kawai, H; Taoka, T

MAGNETIC RESONANCE IN MEDICAL SCIENCES 18 巻 ( 2 ) 頁： 163 - 169 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

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 査読有り Open Access

Yamada, M; Taoka, T; Kawaguchi, A; Yasuda, K; Niinomi, Y; Ohashi, Y; Okuda, T; Naganawa, S

MAGNETIC RESONANCE IN MEDICAL SCIENCES 18 巻 ( 1 ) 頁： 75 - 81 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

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 (SCR max ) 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 SCR max 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 査読有り Open Access

Naganawa, S; Kawai, H; Taoka, T; Sone, M

MAGNETIC RESONANCE IN MEDICAL SCIENCES 18 巻 ( 1 ) 頁： 105 - 108 2019年

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

INTERNATIONAL JOURNAL OF STROKE 13 巻頁： 32 - 32 2018年10月

Corpus callosal involvement is correlated with cognitive impairment in multiple system atrophy 査読有り国際誌

Hara, K; Watanabe, H; Bagarinao, E; Kawabata, K; Yoneyama, N; Ohdake, R; Imai, K; Masuda, M; Yokoi, T; Ogura, A; Tsuboi, T; Ito, M; Atsuta, N; Niwa, H; Taoka, T; Maesawa, S; Naganawa, S; Katsuno, M; Sobue, G

JOURNAL OF NEUROLOGY 265 巻 ( 9 ) 頁： 2079 - 2087 2018年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Neurology

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 査読有り国際共著国際誌 Open Access

Taoka, T; Jost, G; Frenzel, T; Naganawa, S; Pietsch, H

INVESTIGATIVE RADIOLOGY 53 巻 ( 9 ) 頁： 529 - 534 2018年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Investigative Radiology

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

A guide to identification and selection of axial planes in magnetic resonance imaging of the brain 査読有り国際共著国際誌

Otake, S; Taoka, T; Maeda, M; Yuh, WTC

NEURORADIOLOGY JOURNAL 31 巻 ( 4 ) 頁： 336 - 344 2018年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：{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

Prediction of Intracranial Arterial Stenosis Progression in Patients with Moyamoya Vasculopathy: Contrast-Enhanced High-Resolution Magnetic Resonance Vessel Wall Imaging 査読有り国際誌

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

WORLD NEUROSURGERY 116 巻頁： E1114 - E1121 2018年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：World Neurosurgery

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