2024年09月, 日本磁気共鳴医学会, 第52回日本磁気共鳴医学会大会 大会長賞（基礎部門/最優秀賞）　　　　　　　　　　　　　　　
17O標識水のくも膜下腔直接注入とプロトンMRI によるラット大脳表面の水動態の可視化
亀田;藤井;木野田;加藤;尾藤;唐;工藤

2024年09月, 日本磁気共鳴医学会, 2023 MRMS (Magnetic Resonance in Medical Sciences) Most Valuable Reviewer Award　　　　　　　　　　　　　　　
尾藤

2024年09月, 日本磁気共鳴医学会, 日本磁気共鳴医学会優秀論文賞　　　　　　　　　　　　　　　
Three-dimensional multi-parameter mapping of relaxation times and susceptibility using partially RF-spoiled gradient echo
谷口;横沢;白猪;佐藤;雨宮;五月女;尾藤;越智

2023年09月, 日本磁気共鳴医学会, 2022 MRMS (Magnetic Resonance in Medical Sciences) Distinguished Reviewer Award　　　　　　　　　　　　　　　
尾藤

2022年09月, 日本磁気共鳴医学会, 第50回日本磁気共鳴医学会大会 大会長賞（基礎部門/優秀賞）　　　　　　　　　　　　　　　
Low b-value DTI (Low-b DTI)を用いたCSFの動態解析
尾藤;越智;原田;白勢;工藤

2021年11月, 令和3年度関東地方発明表彰 発明奨励賞　　　　　　　　　　　　　　　
高精度な磁化率画像(QSM)を実現するMRI装置
佐藤;白猪;谷口;越智;尾藤

2019年09月, 日本磁気共鳴医学会, 2019 MRMS (Magnetic Resonance in Medical Sciences) Most Valuable Reviewer Award　　　　　　　　　　　　　　　
尾藤

2019年04月, 文部科学省, 平成31年度科学技術分野の文部科学大臣表彰 科学技術賞（開発）　　　　　　　　　　　　　　　
高画質オープン型MRI装置の開発
越智;尾藤;山本;谷口;高橋

2019年03月, 大河内記念会, 第65回（平成30年度）大河内賞 大河内記念賞　　　　　　　　　　　　　　　
生理学的情報を高画質で取得できるオープン型MRI装置の開発
越智;尾藤;山本;谷口;白猪

2018年11月, 平成30年度関東地方発明表彰 発明奨励賞　　　　　　　　　　　　　　　
任意の撮像面を自動設定可能なMRI装置
横沢;谷口;五月女;尾藤

2018年09月, 日本磁気共鳴医学会, 第46回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
17O標識水の第1相臨床試験：安全性および脳血流MRIの実現可能性に関する検討
原田;工藤;亀田;佐藤;白猪;尾藤;藤間;常田;野川;前田;林;佐々木

2017年11月, 平成29年度関東地方発明表彰 発明奨励賞　　　　　　　　　　　　　　　
高画質な拡散尖度画像を取得可能なMRI装置
横沢;越智;尾藤

2016年09月, 日本磁気共鳴医学会, 日本磁気共鳴医学会優秀論文賞　　　　　　　　　　　　　　　
Diffusion-weighted line-scan echo-planar spectroscopic imaging technique to reduce motion artifacts in metabolite diffusion imaging
尾藤;平田;惠飛須;河合;大竹;平田;白猪;五月女;越智;山本;梅田;樋口;田中

2015年12月, 日本磁気共鳴医学会, バイエル学術奨励賞 国際飛躍賞　　　　　　　　　　　　　　　
拡散方向の計測順番最適化によるDWIの体動補正手法
横沢;越智;尾藤

2015年09月, 日本磁気共鳴医学会, 第43回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
アルツハイマー病モデルマウスの脳内代謝物拡散係数の解析
尾藤;Cline;Cross;越智;蓑島

2015年09月, 日本磁気共鳴医学会, 第43回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
定量的磁化率マッピング法における微小静脈の磁化率推定精度の改善
佐藤;白猪;谷口;村瀬;五月女;尾藤;越智

2014年09月, 日本磁気共鳴医学会, 第42回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
拡散尖度画像と定量的磁化率画像を用いたパーキンソン症候群の早期鑑別診断
伊藤;佐々木;大塚;横沢;佐藤;尾藤;原田;上野;山下;樋口;Jonathan;寺山

2013年09月, 日本磁気共鳴医学会, 第41回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
異なる正則化パラメータの組合せによる定量的磁化率マッピング(QSM)法
佐藤;白猪;谷口;村瀬;五月女;越智;尾藤

2012年09月, 日本磁気共鳴医学会, 第40回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
三次元B1分布の高速計測方法
横沢;金子;大竹;谷口;五月女;尾藤

2011年09月, 日本磁気共鳴医学会, 第39回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
Diffusion-weighted Spectroscopic Imagingによる脳虚血モデルラットの解析
尾藤;河合;平田;惠飛須;大竹;平田;白猪;五月女;越智;梅田;樋口;田中

2009年12月, 日本磁気共鳴医学会, バイエル学術奨励賞 国際飛躍賞　　　　　　　　　　　　　　　
EPSIにおける代謝物質信号と水信号の同時計測
白猪;平田;山本;尾藤

2009年10月, 日本磁気共鳴医学会, 第37回日本磁気共鳴医学会大会 学術奨励賞　　　　　　　　　　　　　　　
Diffusion-weighted Line-scan Echo-planar Spectroscopic Imagingによる代謝物拡散計測の精度向上
尾藤;平田;惠飛須;河合;大竹;平田;白猪;五月女;越智;梅田;樋口;田中

Utility of under-sampled scans with iterative reconstruction and high-frequency preserving transform for high spatial resolution magnetic resonance cholangiopancreatography.
Kondo S, Yuko Nakamura, Higaki T, Nishihara T, Takizawa M, Shirai T, Fujimori M, Bito Y, Narita K, Fonseca D, Maeda S, Kawashita I, Honda Y, Awai K
Japanese journal of radiology, 2024年11月05日
研究論文（学術雑誌）,

Purpose

Under-sampled scans with iterative reconstruction and high-frequency preserving transform (Us-IRHF) can increase the acquisition speed without degrading the image quality by recovering image information from under-sampled data. We investigate the clinical applicability of high spatial resolution magnetic resonance cholangiopancreatography (MRCP) images without extending the scanning time using Us-IRHF.

Methods

A slit phantom was scanned with conventional- (without Us-IRHF), Us-IR- (without HF), and Us-IRHF scanning. The matrix size was 320 × 320 for Us-IR- and Us-IRHF- and 288 × 208 for conventional scanning. Modulation transfer function (MTF) focused on the 1.0 lp/cm gauge for each scanning was calculated. For clinical study we acquired respiratory-triggered 3D MRCP scans with and without Us-IRHF (U⁺-, U^-MRCP) in 41 patients. The matrix size was 320 × 320 for U⁺- and 288 × 208 for U^-MRCP. The acquisition time and the relative duct-to-periductal contrast ratios (RCs) for the right- and left intrahepatic bile-, the common bile-, and the main pancreatic duct were recorded. Visualization of each duct and overall image quality was scored on 5-point confidence scales. For visualization of each duct the score ranged from 1 (not visible) to 5 (visible with excellent details), for the image quality, it ranged from 1 (undiagnostic) to 5 (excellent). Superiority for the qualitative visualization score and non-inferiority for the RC values with prespecified margins were assessed.

Results

Phantom study showed that compared to the conventional- and Us-IR (without HF) images, the MTF for the Us-IRHF image revealed the highest response. For clinical study, the mean acquisition time was 161 s for U⁺- and 165 s for U^-MRCP. For all ducts, the RC value of U⁺MRCP was non-inferior to U^-MRCP and the qualitative visualization score assigned to U⁺MRCP was superior to U^-MRCP.

Conclusion

Us-IRHF improved the image quality of high spatial resolution MRCP without extending the scanning time.

Accelerating FLAIR imaging via deep learning reconstruction: potential for evaluating white matter hyperintensities
Noriko Nishioka, Yukie Shimizu, Yukio Kaneko, Toru Shirai, Atsuro Suzuki, Tomoki Amemiya, Hisaaki Ochi, Yoshitaka Bito, Masahiro Takizawa, Yohei Ikebe, Hiroyuki Kameda, Taisuke Harada, Noriyuki Fujima, Kohsuke Kudo
Japanese Journal of Radiology, 2024年09月24日
英語, 研究論文（学術雑誌）, Abstract
Purpose
To evaluate deep learning-reconstructed (DLR)–fluid-attenuated inversion recovery (FLAIR) images generated from undersampled data, compare them with fully sampled and rapidly acquired FLAIR images, and assess their potential for white matter hyperintensity evaluation.

Materials and methods
We examined 30 patients with white matter hyperintensities, obtaining fully sampled FLAIR images (standard FLAIR, std-FLAIR). We created accelerated FLAIR (acc-FLAIR) images using one-third of the fully sampled data and applied deep learning to generate DLR–FLAIR images. Three neuroradiologists assessed the quality (amount of noise and gray/white matter contrast) in all three image types. The reproducibility of hyperintensities was evaluated by comparing a subset of 100 hyperintensities in acc-FLAIR and DLR–FLAIR images with those in the std-FLAIR images. Quantitatively, similarities and errors of the entire image and the focused regions on white matter hyperintensities in acc-FLAIR and DLR–FLAIR images were measured against std-FLAIR images using structural similarity index measure (SSIM), regional SSIM, normalized root mean square error (NRMSE), and regional NRMSE values.

Results
All three neuroradiologists evaluated DLR–FLAIR as having significantly less noise and higher image quality scores compared with std-FLAIR and acc-FLAIR (p < 0.001). All three neuroradiologists assigned significantly higher frontal lobe gray/white matter visibility scores for DLR–FLAIR than for acc-FLAIR (p < 0.001); two neuroradiologists attributed significantly higher scores for DLR–FLAIR than for std-FLAIR (p < 0.05). Regarding white matter hyperintensities, all three neuroradiologists significantly preferred DLR–FLAIR (p < 0.0001). DLR–FLAIR exhibited higher similarity to std-FLAIR in terms of visibility of the hyperintensities, with 97% of the hyperintensities rated as nearly identical or equivalent. Quantitatively, DLR–FLAIR demonstrated significantly higher SSIM and regional SSIM values than acc-FLAIR, with significantly lower NRMSE and regional NRMSE values (p < 0.0001).

Conclusions
DLR–FLAIR can reduce scan time and generate images of similar quality to std-FLAIR in patients with white matter hyperintensities. Therefore, DLR–FLAIR may serve as an effective method in traditional magnetic resonance imaging protocols.

Assessment of accuracy and repeatability of quantitative parameter mapping in MRI
Yuya Hirano, Kinya Ishizaka, Hiroyuki Sugimori, Yo Taniguchi, Tomoki Amemiya, Yoshitaka Bito, Kohsuke Kudo
Radiological Physics and Technology, 2024年08月28日
英語, 研究論文（学術雑誌）, AbstractWe aimed to evaluate the accuracy and repeatability of the T1, T2*, and proton density (PD) values obtained by quantitative parameter mapping (QPM) using the ISMRM/NIST MRI system phantom and compared them with computer simulations. We compared the relaxation times and PD obtained through QPM with the reference values of the ISMRM/NIST MRI system phantom and conventional methods. Furthermore, we evaluated the presence or absence of influences other than noise in T1 and T2* values obtained by QPM by comparing the obtained coefficient of variation (CV) with simulation results. The T1, T2*, and PD values by QPM showed a strong correlation with the measured values and the referenced values. The simulated CVs of QPM calculated for each sphere showed similar trends to those of the actual scans.

Conversion map from quantitative parameter mapping to myelin water fraction: comparison with R₁·R₂^* and myelin water fraction in white matter
Kitano S, Kanazawa Y, Harada M, Taniguchi Y, Hayashi H, MatsumotoY, Ito K, Bito Y, Haga A
Magnetic Resonance Materials in Physics, Biology, and Medicine (MAGMA), 2024年
研究論文（学術雑誌）

Automated Detection of Cerebral Microbleeds on Two-dimensional Gradient-recalled Echo T2* Weighted Images Using a Morphology Filter Bank and Convolutional Neural Network
Noriko Nishioka, Yukie Shimizu, Toru Shirai, Hisaaki Ochi, Yoshitaka Bito, Kiichi Watanabe, Hiroyuki Kameda, Taisuke Harada, Kohsuke Kudo
Magnetic Resonance in Medical Sciences, Japanese Society for Magnetic Resonance in Medicine, 2024年
研究論文（学術雑誌）

Nature of the Intracellular-contrast-enhancing Fat-saturated T1-weighted Gradient-echo (ICE-TIGRE) Sequence: A Fat-suppressed T1-weighted Technique with Motion-sensitised Driven-equilibrium for Improved Contrast Enhancement in Liver Imaging
Nishihara T, Nakamura Y, Yoshizawa N, Takizawa M, Shirai T, Higaki T, Honda Y, Awai K, Bito Y
Magnetic Resonance in Medical Sciences, 2024年, ［最終著者］
研究論文（学術雑誌）

Differences of white matter structure for diffusion kurtosis imaging using voxel-based morphometry and connectivity analysis
Yuki Kanazawa, Natsuki Ikemitsu, Yuki Kinjo, Masafumi Harada, Hiroaki Hayashi, Yo Taniguchi, Kosuke Ito, Yoshitaka Bito, Yuki Matsumoto, Akihiro Haga
BJR|Open, 6, 1, 1, 7, Oxford University Press (OUP), 2023年12月12日
研究論文（学術雑誌）, Abstract

Objectives

In a clinical study, diffusion kurtosis imaging (DKI) has been used to visualize and distinguish white matter (WM) structures’ details. The purpose of our study is to evaluate and compare the diffusion tensor imaging (DTI) and DKI parameter values to obtain WM structure differences of healthy subjects.

Methods

Thirteen healthy volunteers (mean age, 25.2 years) were examined in this study. On a 3-T MRI system, diffusion dataset for DKI was acquired using an echo-planner imaging sequence, and T1-weghted (T1w) images were acquired. Imaging analysis was performed using Functional MRI of the brain Software Library (FSL). First, registration analysis was performed using the T1w of each subject to MNI152. Second, DTI (eg, fractional anisotropy [FA] and each diffusivity) and DKI (eg, mean kurtosis [MK], radial kurtosis [RK], and axial kurtosis [AK]) datasets were applied to above computed spline coefficients and affine matrices. Each DTI and DKI parameter value for WM areas was compared. Finally, tract-based spatial statistics (TBSS) analysis was performed using each parameter.

Results

The relationship between FA and kurtosis parameters (MK, RK, and AK) for WM areas had a strong positive correlation (FA-MK, R2 = 0.93; FA-RK, R2 = 0.89) and a strong negative correlation (FA-AK, R2 = 0.92). When comparing a TBSS connection, we found that this could be observed more clearly in MK than in RK and FA.

Conclusions

WM analysis with DKI enable us to obtain more detailed information for connectivity between nerve structures.

Advances in knowledge

Quantitative indices of neurological diseases were determined using segmenting WM regions using voxel-based morphometry processing of DKI images.

Prediction of amyloid positron emission tomography positivity using multiple regression analysis of quantitative susceptibility mapping
Yohei Ikebe, Ryota Sato, Tomoki Amemiya, Niki Udo, Masaaki Matsushima, Ichiro Yabe, Akinori Yamaguchi, Makoto Sasaki, Masafumi Harada, Noriyuki Matsukawa, Yasuo Kawata, Yoshitaka Bito, Toru Shirai, Hisaaki Ochi, Kohsuke Kudo
Magnetic Resonance Imaging, 103, 192, 197, Elsevier {BV}, 2023年11月
英語, 研究論文（学術雑誌）

Three-dimensional Multi-parameter Mapping of Relaxation Times and Susceptibility Using Partially RF-spoiled Gradient Echo.
Taniguchi Y, Yokosawa S, Shirai T, Sato R, Amemiya T, Soutome Y, Bito Y, Ochi H
Magnetic resonance in medical sciences, 22, 4, 459, 468, 2023年07月30日
研究論文（学術雑誌）,

Purpose

MR parameter mapping is a technique that obtains distributions of parameters such as relaxation time and proton density (PD) and is starting to be used for disease quantification in clinical diagnoses. Quantitative susceptibility mapping is also promising for the early diagnosis of brain disorders such as degenerative neurological disorders. Therefore, we developed an MR quantitative parameter mapping (QPM) method to map four tissue-related parameters (T₁, T₂*, PD, and susceptibility) and B₁ simultaneously by using a 3D partially RF-spoiled gradient echo (pRSGE). We verified the accuracy and repeatability of QPM in phantom and volunteer experiments.

Methods

Tissue-related parameters are estimated by varying four scan parameters of the 3D pRSGE: flip angle, RF-pulse phase increment, TR and TE, performing multiple image scans, and finding a least-squares fit for an intensity function (which expresses the relationship between the scan parameters and intensity values). The intensity function is analytically complex, but by using a Bloch simulation to create it numerically, the least-squares fitting can be used to estimate the quantitative values. This has the advantage of shortening the image-reconstruction processing time needed to estimate the quantitative values than with methods using pattern matching.

Results

A 1.1-mm isotropic resolution scan covering the whole brain was completed with a scan time of approximately 12 minutes, and the reconstruction time using a GPU was approximately 1 minute. The phantom experiments confirmed that both the accuracy and repeatability of the quantitative values were high. The volunteer scans also confirmed that the accuracy of the quantitative values was comparable to that of conventional methods.

Conclusion

The proposed QPM method can map T₁, T₂*, PD, susceptibility, and B₁ simultaneously within a scan time that can be applied to human subjects.

Characterization of Breast Tumors from MR Images Using Radiomics and Machine Learning Approaches
Khuram Faraz, Grégoire Dauce, Amine Bouhamama, Benjamin Leporq, Hajime Sasaki, Yoshitaka Bito, Olivier Beuf, frank PILLEUL
Journal of Personalized Medicine, 13, 7, 1062, 1062, {MDPI} {AG}, 2023年06月28日
英語, 研究論文（学術雑誌）, Determining histological subtypes, such as invasive ductal and invasive lobular carcinomas (IDCs and ILCs) and immunohistochemical markers, such as estrogen response (ER), progesterone response (PR), and the HER2 protein status is important in planning breast cancer treatment. MRI-based radiomic analysis is emerging as a non-invasive substitute for biopsy to determine these signatures. We explore the effectiveness of radiomics-based and CNN (convolutional neural network)-based classification models to this end. T1-weighted dynamic contrast-enhanced, contrast-subtracted T1, and T2-weighted MR images of 429 breast cancer tumors from 323 patients are used. Various combinations of input data and classification schemes are applied for ER+ vs. ER−, PR+ vs. PR−, HER2+ vs. HER2−, and IDC vs. ILC classification tasks. The best results were obtained for the ER+ vs. ER− and IDC vs. ILC classification tasks, with their respective AUCs reaching 0.78 and 0.73 on test data. The results with multi-contrast input data were generally better than the mono-contrast alone. The radiomics and CNN-based approaches generally exhibited comparable results. ER and IDC/ILC classification results were promising. PR and HER2 classifications need further investigation through a larger dataset. Better results by using multi-contrast data might indicate that multi-parametric quantitative MRI could be used to achieve more reliable classifiers.

Low b-value Diffusion Tensor Imaging to Analyze the Dynamics of Cerebrospinal Fluid: Resolving Intravoxel Pseudorandom Motion into Ordered and Disordered Motions
Yoshitaka Bito, Hisaaki Ochi, Ryuji Shirase, Wataru Yokohama, Kuniaki Harada, Kohsuke Kudo
Magnetic Resonance in Medical Sciences, Japanese Society for Magnetic Resonance in Medicine, 2023年, ［筆頭著者］
英語, 研究論文（学術雑誌）

Efficacy of Quantitative Susceptibility Mapping with Brain Surface Correction and Vein Removal for Detecting Increase Magnetic Susceptibility in Patients with Alzheimer’s Disease
Akinori Yamaguchi, Kohsuke Kudo, Ryota Sato, Yasuo Kawata, Niki Udo, Masaaki Matsushima, Ichiro Yabe, Makoto Sasaki, Masafumi Harada, Noriyuki Matsukawa, Toru Shirai, Hisaaki Ochi, Yoshitaka Bito
Magnetic Resonance in Medical Sciences, 22, 1, 87, 94, Japanese Society for Magnetic Resonance in Medicine, 2023年
英語, 研究論文（学術雑誌）

Utility of Wavelet Denoising with Geometry Factor Weighting for Gadoxetic Acid-enhanced Hepatobiliary-phase MR Imaging
Shota Kondo, Yuko Nakamura, Toru Higaki, Takashi Nishihara, Masahiro Takizawa, Toru Shirai, Motoshi Fujimori, Yoshitaka Bito, Keigo Narita, Takahiro Sueoka, Yukiko Honda, Chihiro Tani, Kazuo Awai
Magnetic Resonance in Medical Sciences, 22, 2, 241, 252, Japanese Society for Magnetic Resonance in Medicine, 2023年
英語, 研究論文（学術雑誌）

Myelin-weighted imaging derived from quantitative parameter mapping
Yuki Kanazawa, Masafumi Harada, Yo Taniguchi, Hiroaki Hayashi, Takashi Abe, Maki Otomo, Yuki Matsumoto, Masaharu Ono, Kosuke Ito, Yoshitaka Bito, Akihiro Haga
European Journal of Radiology, 156, 110525, 110525, Elsevier {BV}, 2022年11月
英語, 研究論文（学術雑誌）

Quantitative Susceptibility Mapping versus R2*-based Histogram Analysis for Evaluating Liver Fibrosis: Preliminary Results.
Masato Yoshikawa, Kohsuke Kudo, Taisuke Harada, Kazutaka Harashima, Jun Suzuki, Koji Ogawa, Taro Fujiwara, Mutsumi Nishida, Ryota Sato, Toru Shirai, Yoshitaka Bito
Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 21, 4, 609, 622, 2022年10月01日, ［国内誌］
英語, 研究論文（学術雑誌）, PURPOSE: The staging of liver fibrosis is clinically important, and a less invasive method is preferred. Quantitative susceptibility mapping (QSM) has shown a great potential in estimating liver fibrosis in addition to R2* relaxometry. However, few studies have compared QSM analysis and liver fibrosis. We aimed to evaluate the feasibility of estimating liver fibrosis by using QSM and R2*-based histogram analyses by comparing it with ultrasound-based transient elastography and the stage of histologic fibrosis. METHODS: Fourteen patients with liver disease were enrolled. Data sets of multi-echo gradient echo sequence with breath-holding were acquired on a 3-Tesla scanner. QSM and R2* were reconstructed by water-fat separation method, and ROIs were analyzed for these images. Quantitative parameters with histogram features (mean, variance, skewness, kurtosis, and 1st, 10th, 50th, 90th, and 99th percentiles) were extracted. These data were compared with the elasticity measured by ultrasound transient elastography and histological stage of liver fibrosis (F0 to F4, based on the new Inuyama classification) determined by biopsy or hepatectomy. The correlation of histogram parameters with intrahepatic elasticity and histologically confirmed fibrosis stage was examined. Texture parameters were compared between subgroups divided according to fibrosis stage. Receiver operating characteristic (ROC) analysis was also performed. P < 0.05 indicated statistical significance. RESULTS: The six histogram parameters of both QSM and R2*were significantly correlated with intrahepatic elasticity. In particular, three parameters (variance, percentiles [90th and 99th]) of QSM showed high correlation (r = 0.818-0.844), whereas R2* parameters showed a moderate correlation with elasticity. Four parameters of QSM were significantly correlated with fibrosis stage (ρ = 0.637-0.723) and differentiated F2-4 from F0-1 fibrosis and F3-4 from F0-2 fibrosis with areas under the ROC curve of > 0.8, but those of R2* did not. CONCLUSION: QSM may serve as a promising surrogate indicator in detecting liver fibrosis.

Quantitative Susceptibility Mapping: Basic Methods and Clinical Applications
Harada T., Kudo K., Fujima N., Yoshikawa M., Ikebe Y., Sato R., Shirai T., Bito Y., Uwano I., Miyata M.
Radiographics, 42, 4, 1161, 1176, Radiological Society of North America ({RSNA}), 2022年07月, ［査読有り］
研究論文（学術雑誌）

Phase I Randomized Trial of ¹⁷O‐Labeled Water: Safety and Feasibility Study of Indirect Proton MRI for the Evaluation of Cerebral Water Dynamics
Taisuke Harada, Kohsuke Kudo, Hiroyuki Kameda, Ryota Sato, Toru Shirai, Yoshitaka Bito, Noriyuki Fujima, Satonori Tsuneta, Toshifumi Nogawa, Kenichiro Maeda, Hiroshi Hayashi, Makoto Sasaki
Journal of Magnetic Resonance Imaging, 56, 6, 1874, 1882, Wiley, 2022年04月30日
研究論文（学術雑誌）, Background

¹⁷O‐labeled water (PSO17) is a contrast agent developed to measure brain water dynamics and cerebral blood flow.

Purpose

To evaluate the safety and feasibility of PSO17.

Study Type

Prospective study.

Subjects

A total of 12 male healthy volunteers (23.1 ± 1.9 years) were assigned to three groups of four subjects: placebo (normal saline), PSO17 10%, and PSO17 20%.

Field Strength/Sequence

Dynamic 3D fluid attenuated inversion recovery (FLAIR, fast spin echo with variable refocusing flip angle) scans of the brain were performed with 3‐T MRI.

Assessment

Contrast agents were injected 5 minutes after the start of a 10‐minute scan. Any symptoms, vital signs, and blood and urine tests were evaluated at five timepoints from preinjection to 4 days after. Blood samples for pharmacokinetic analysis, including half‐life (T1/2), maximum fraction (C_max), time‐to‐maximum fraction (T_max), and area under the curve (AUC), were collected at 13 timepoints from preinjection to 168 hours after. Regions of interest were set in the cerebral cortex (CC), basal ganglia/thalamus (BG/TM), and white matter (WM), and ¹⁷O concentrations were calculated from signal changes and evaluated using C_max.

Statistical Tests

All items were compared among the three groups using Tukey–Kramer's honestly significant difference test. Statistical significance was defined as P < 0.5.

Results

No safety issues were noted with the intravenous administration of PSO17. The T1/2 was approximately 160 hours, and the AUCs were 1.77 ± 0.10 and 3.75 ± 0.36 in the PSO17 10% and 20% groups, respectively. ¹⁷O fractions calculated from MRI signals were higher in the PSO17 20% group than in the 10% and placebo groups. Significant differences were noted between all pairs of groups in the CC and BG/TM, and between PSO17 20% and both placebo and 10% groups in the WM.

Data Conclusion

PSO17 might be considered safe as a contrast medium. Dynamic 3D‐FLAIR might detect dose‐dependent signal changes and estimate ¹⁷O.

Evidence Level

1

Technical Efficacy

Stage 1

Quantitative parameter mapping of contrast agent concentration and relaxivity and brain tumor extracellular pH.
Matsumoto Y, Harada M, Kanazawa Y, Taniguchi Y, Ono M, Bito Y
Scientific reports, 12, 1, 2171, 2022年02月09日
研究論文（学術雑誌）, In clinical magnetic resonance imaging, gadolinium-based contrast agents are commonly used for detecting brain tumors and evaluating the extent of malignancy. We present a new method to evaluate relaxivity (r1) and contrast agent concentration separately in contrast-enhanced lesions using quantitative parameter mapping (QPM). Furthermore, we also aimed to estimate the extracellular pH (pHe) of tumor lesions. We demonstrated that it is possible to evaluate pathophysiological tumor changes due to therapeutic efficacy by measuring r1 in contrast-enhanced lesions. In this study, the primary brain tumor group showed significantly higher r1 values than other brain disease groups (P < 0.001). Moreover, mean pHe value showed a trend for tumor malignancy having a lower pHe value and primary brain tumor having a significantly lower pHe than other brain diseases (P < 0.001). Our results might suggest that QPM can separately quantify r1 and CA concentration in brain tumors and that pHe brain tumor mapping could serve as a tumor biomarker. In conclusion, our method has potential clinical applications for assessing the treatment effects.

A diagnostic index based on quantitative susceptibility mapping and voxel-based morphometry may improve early diagnosis of Alzheimer's disease.
Sato R, Kudo K, Udo N, Matsushima M, Yabe I, Yamaguchi A, Tha KK, Sasaki M, Harada M, Matsukawa N, Amemiya T, Kawata Y, Bito Y, Ochi H, Shirai T
European radiology, 32, 7, 4479, 4488, 2022年02月08日
研究論文（学術雑誌）,

Objectives

Voxel-based morphometry (VBM) is widely used to quantify the progression of Alzheimer's disease (AD), but improvement is still needed for accurate early diagnosis. We evaluated the feasibility of a novel diagnosis index for early diagnosis of AD based on quantitative susceptibility mapping (QSM) and VBM.

Methods

Thirty-seven patients with AD, 24 patients with mild cognitive impairment (MCI) due to AD, and 36 cognitively normal (NC) subjects from four centers were included. A hybrid sequence was performed by using 3-T MRI with a 3D multi-echo GRE sequence to obtain both a T1-weighted image for VBM and phase images for QSM. The index was calculated from specific voxels in QSM and VBM images by using a linear support vector machine. The method of voxel extraction was optimized to maximize diagnostic accuracy, and the optimized index was compared with the conventional VBM-based index using receiver operating characteristic analysis.

Results

The index was optimal when voxels were extracted as increased susceptibility (AD > NC) in the parietal lobe and decreased gray matter volume (AD < NC) in the limbic system. The optimized proposed index showed excellent performance for discrimination between AD and NC (AUC = 0.94, p = 1.1 × 10^-10) and good performance for MCI and NC (AUC = 0.87, p = 1.8 × 10^-6), but poor performance for AD and MCI (AUC = 0.68, p = 0.018). Compared with the conventional index, AUCs were improved for all cases, especially for MCI and NC (p < 0.05).

Conclusions

In this preliminary study, the proposed index based on QSM and VBM improved the diagnostic performance between MCI and NC groups compared with the VBM-based index.

Key points

• We developed a novel diagnostic index for Alzheimer's disease based on quantitative susceptibility mapping (QSM) and voxel-based morphometry (VBM). • QSM and VBM images can be acquired simultaneously in a single sequence with little increasing scan time. • In this preliminary study, the proposed diagnostic index improved the discriminative performance between mild cognitive impairment and normal control groups compared with the conventional VBM-based index.

Region Expansion of Background Field Removal with Local Spherical Harmonics Approximation for Whole-brain Quantitative Susceptibility Mapping
Toru Shirai, Ryota Sato, Yasuo Kawata, Yoshitaka Bito, Hisaaki Ochi
Magnetic Resonance in Medical Sciences, 22, 4, 497, 514, Japanese Society for Magnetic Resonance in Medicine, 2022年
英語, 研究論文（学術雑誌）

Low b‐value diffusion tensor imaging for measuring pseudorandom flow of cerebrospinal fluid
Yoshitaka Bito, Kuniaki Harada, Hisaaki Ochi, Kohsuke Kudo
Magnetic Resonance in Medicine, 86, 3, 1369, 1382, 2021年09月, ［筆頭著者］
研究論文（学術雑誌）

Utility of Radial Scanning for the Identification of Arterial Hypervascularity of Hepatocellular Carcinoma on Gadoxetic Acid-Enhanced Magnetic Resonance Images.
Narita K, Nakamura Y, Higaki T, Nishihara T, Harada K, Takizawa M, Shirase R, Bito Y, Akagi M, Honda Y, Iida M, Awai K
Journal of computer assisted tomography, 45, 3, 359, 366, 2021年03月03日
研究論文（学術雑誌）,

Objectives

This study aimed to compare the accuracy of assessing the arterial hypervascularity of hepatocellular carcinoma (HCC) on dynamic computed tomography (CT) scans and gadoxetic acid (EOB)-enhanced magnetic resonance imaging (MRI) scans performed with radial sampling.

Methods

We studied the images of 40 patients with hypervascular HCC. A radiologist recorded the standard deviation of the attenuation (or the signal intensity [SI]) in subcutaneous fat tissue as the image noise (N) and calculated the contrast-to-noise ratio (CNR) as follows: (CNR) = (n-ROIT - n-ROIL)/N, where n-ROIT is the mean attenuation (or SI) of the tumor divided by the mean attenuation (or SI) of the aorta and n-ROIL is the mean attenuation (or SI) of the liver parenchyma divided by the mean attenuation (or SI) of the aorta.

Results

The CNR was significantly higher on EOB-enhanced MRI than on dynamic CT scans.

Conclusions

For the assessment of HCC vascularity, EOB-enhanced MRI scans acquired with radial sampling were more accurate than dynamic CT images.

Quantitative susceptibility mapping of prostate with separate calculations for water and fat regions for reducing shading artifacts
Ryota Sato, Toru Shirai, Yoshihisa Soutome, Yoshitaka Bito, Hisaaki Ochi
Magnetic Resonance Imaging, 66, 22, 29, Elsevier BV, 2020年02月
研究論文（学術雑誌）

MRI構造画像と磁化率画像に基づくアルツハイマー病の診断指標　　　　　　　　　　　　　　　
佐藤 良太, 工藤 與亮, 河田 康雄, 宇土 仁木, 松島 理明, 矢部 一郎, 山口 晃典, 尾藤 良孝, 越智 久晃, 白猪 亨
Dementia Japan, 33, 4, 553, 553, (一社)日本認知症学会, 2019年10月
日本語

Pseudo-random Trajectory Scanning Suppresses Motion Artifacts on Gadoxetic Acid-enhanced Hepatobiliary-phase Magnetic Resonance Images
Nakamura Y, Higaki T, Nishihara T, Harada K, Takizawa M, Bito Y, Narita K, Akagi M, Matsubara Y, Kamioka S, Akiyama Y, Iida M, Awai K
Magnetic Resonance in Medical Sciences, 19, 1, 21, 28, 2019年
英語, 研究論文（学術雑誌）

Susceptibility difference weighted imaging in vertical-field MRI
Ryota Sato, Toru Shirai, Yo Taniguchi, Takenori Murase, Yoshitaka Bito, Yoshihisa Soutome, Hisaaki Ochi
Radiological Physics and Technology, 11, 2, 255, 261, Springer Science and Business Media LLC, 2018年04月26日
研究論文（学術雑誌）

B1-control receive array coil (B-RAC) for reducing B1+ inhomogeneity in abdominal imaging at 3T-MRI
Yukio Kaneko, Yoshihisa Soutome, Hideta Habara, Yoshitaka Bito, Hisaaki Ochi
Journal of Magnetic Resonance, 287, 25, 32, Elsevier BV, 2018年02月
研究論文（学術雑誌）

Quantitative Susceptibility Mapping Using the Multiple Dipole-inversion Combination with k-space Segmentation Method
Ryota Sato, Toru Shirai, Yo Taniguchi, Takenori Murase, Yoshitaka Bito, Hisaaki Ochi
Magnetic Resonance in Medical Sciences, 16, 4, 340, 350, Japanese Society for Magnetic Resonance in Medicine, 2017年
研究論文（学術雑誌）

Optimization of Scan Parameters to Reduce Acquisition Time for Diffusion Kurtosis Imaging at 1.5T
Suguru YOKOSAWA, Makoto SASAKI, Yoshitaka BITO, Kenji ITO, Fumio YAMASHITA, Jonathan GOODWIN, Satomi HIGUCHI, Kohsuke KUDO
Magnetic Resonance in Medical Sciences, 15, 1, 41, 48, Japanese Society for Magnetic Resonance in Medicine, 2016年
研究論文（学術雑誌）

Diffusion-weighted Line-scan Echo-planar Spectroscopic Imaging Technique to Reduce Motion Artifacts in Metabolite Diffusion Imaging
Yoshitaka BITO, Koji HIRATA, Toshihiko EBISU, Yuko KAWAI, Yosuke OTAKE, Satoshi HIRATA, Toru SHIRAI, Yoshihisa SOUTOME, Hisaaki OCHI, Etsuji YAMAMOTO, Masahiro UMEDA, Toshihiro HIGUCHI, Chuzo TANAKA
Magnetic Resonance in Medical Sciences, 14, 1, 43, 50, Japanese Society for Magnetic Resonance in Medicine, 2015年
研究論文（学術雑誌）

Magnetic susceptibility and magnetic resonance measurements of the moisture content and hydration condition of a magnetic mixture material
K. Tsukada, T. Kusaka, M. M. Saari, R. Takagi, K. Sakai, T. Kiwa, Y. Bito
Journal of Applied Physics, 115, 17, AIP Publishing, 2014年01月02日
研究論文（学術雑誌）, We developed a magnetic measurement method to measure the moisture content and hydration condition of mortar as a magnetic mixture material. Mortar is a mixture of Portland cement, sand, and water, and these materials exhibit different magnetic properties. The magnetization–magnetic field curves of these components and of mortars with different moisture contents were measured, using a specially developed high-temperature-superconductor superconducting quantum interference device. Using the differences in magnetic characteristics, the moisture content of mortar was measured at the ferromagnetic saturation region over 250 mT. A correlation between magnetic susceptibility and moisture content was successfully established. After Portland cement and water are mixed, hydration begins. At the early stage of the hydration/gel, magnetization strength increased over time. To investigate the magnetization change, we measured the distribution between bound and free water in the mortar in the early stage by magnetic resonance imaging (MRI). The MRI results suggest that the amount of free water in mortar correlates with the change in magnetic susceptibility.

Double-tuned Radiofrequency Coil for 19F and 1H Imaging
Yosuke OTAKE, Yoshihisa SOUTOME, Koji HIRATA, Hisaaki OCHI, Yoshitaka BITO
Magnetic Resonance in Medical Sciences, 13, 3, 199, 205, Japanese Society for Magnetic Resonance in Medicine, 2014年
研究論文（学術雑誌）

FLUORINE MAGNETIC RESONANCE IMAGING (F-19-MRI) FOR NONINVASIVE IN VIVO DETECTION OF TISSUE DISTRIBUTIONS USING PERFLUOROCARBON NANOPARTICLE EMULSIONS AT 3T
Yoshitaka Bito
Drug Metabolism Reviews, 2007年
研究論文（学術雑誌）

Resource management simulator for radiology departments.
Yui, S., Sasaki, H., Bito, Y., Ban, H., Kitamura, M., Nakashima, T., Obara, T.
AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium, 1165, 1165, 2007年
研究論文（学術雑誌）

Visualization method for finding critical care factors in variance analysis.
Yui, S., Bito, Y., Obara, K., Kamiyama, T., Seto, K., Ban, H., Hashizume, A., Haga, M., Oka, Y.
AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium, 1153, 1153, 2006年
研究論文（学術雑誌）

Lactate discrimination incorporated into echo‐planar spectroscopic imaging
Yoshitaka Bito, Toshihiko Ebisu, Satoshi Hirata, Tetsuro Takegami, Yukari Yamamoto, Chuzo Tanaka, Shoji Naruse
Magnetic Resonance in Medicine, 45, 4, 568, 574, Wiley, 2001年03月27日
研究論文（学術雑誌）, Abstract

A technique for discriminating a lactate signal from overlapping lipid signals in ¹H spectroscopic imaging is presented. It is based on J‐coupling between lactate protons and on the broad spectral bandwidth of lipid signal. Measurement parameters used in the technique are determined so that TE is separated from n/J (n: a natural number, J: J‐coupling constant) enough to suppress the lipid signal at the time when the lactate signal is strongest. Data processing is used to calculate the lactate signal intensity from the reconstructed spectra. This technique enables lactate to be discriminated in a single measurement and enables spectra of other metabolites to be acquired simultaneously. However, it necessitates a homogeneous magnetic field, long TE, and supplementary lipid suppression. Discrimination of the lactate signal is demonstrated by applying lactate‐discriminating echo‐planar spectroscopic imaging (EPSI), which combines this discrimination technique with the standard EPSI, to rat focal cerebral ischemia models. Magn Reson Med 45:568–574, 2001. © 2001 Wiley‐Liss, Inc.

Mismatch between lactate and the apparent diffusion coefficient of water in progressive focal ischemia.
Takegami T, Ebisu T, Bito Y, Hirata S, Yamamoto Y, Tanaka C, Naruse S, Mineura K
NMR in biomedicine, 14, 5, 11, 2001年02月01日, ［査読有り］
研究論文（学術雑誌）, In this study, we examined mismatch in the area indicated by the normal apparent diffusion coefficient (ADC) of water and increased lactate in the early stage of focal cerebral ischemia. Five rats were subjected to permanent middle cerebral artery (MCA) occlusion. Diffusion-weighted echo planar imaging (DWEPI) and proton echo planar spectroscopic imaging (EPSI) were performed from 20 to 170 min after MCA occlusion, and lactate and N-acetyl asparate images were obtained by EPSI. Postmortem histological analysis was also performed. The areas of increased lactate and normal ADC were observed in the surrounding border zone of ischemia at approximately 20 min after MCA occlusion. This initial lactate in the border zone was significantly higher than that in the normal area, but lower than that in the ischemic core, which showed a reduction of ADC. However, this area was progressively involved in the ischemic core at 170 min without any treatment. The lactate-ADC mismatch in the initial period of ischemia may offer unique diagnostic information for ischemic tissue at high risk, followed by progressive involvement in the ischemic core without treatment. Considering that the accumulation of initial lactate in this area was not excessive, our findings may suggest that the lactate-ADC mismatch in the early period of ischemia indicates potentially salvageable tissue at high risk, requiring aggressive treatment.

Interactively visualizing data warehouses
Yoshitaka Bito, Kero R., Matsuo H., Shintani Y., Silver M.
Journal of Healthcare Information Management: JHIM, 15, 2, 133, 142, 2001年, ［筆頭著者］
研究論文（学術雑誌）

Expansion of the spectral bandwidth by spatial and chemical shift selective saturation in high‐speed magnetic resonance spectroscopic imaging
Satoshi Hirata, Yoshitaka Bito, Etsuji Yamamoto
Magnetic Resonance in Medicine, 35, 4, 611, 616, Wiley, 1996年04月
研究論文（学術雑誌）, Abstract

A new spectral bandwidth expansion technique for highspeed magnetic resonance spectroscopic imaging (MRSI) based on an echo‐planar technique is presented. This expansion can be achieved by spatial and chemical shift selective saturation without increasing the total measurement time. In addition, displacement along the slice‐select direction due to chemical‐shift differences between the measured compounds is also suppressed. Experimental results are shown using a phantom consisting of benzene and acetone. High spatial resolution (1 × 1 mm²) and wide spectral bandwidth (1.5–1.8 kHz; the effective spectral bandwidth has been doubled) are obtained without the displacement along the slice‐select direction.

A high‐speed MRI simulator using the transition matrix method and periodicity of magnetization
Yo Taniguchi, Chitose Nakaya, Yoshitaka Bito, Etsuji Yamamoto
Systems and Computers in Japan, 26, 2, 54, 62, Wiley, 1995年01月
研究論文（学術雑誌）, Abstract

An MRI simulator is a tool for understanding MR phenomena and developing new pulse sequences, which determine picture quality and information included in MR signals. Conventional simulators calculate the Bloch equations approximately to reduce the computation time. This paper presents a technique for solving the equations exactly at high speed and for creating images. The processing time is made practical by using the transition matrix method and the periodicity of the magnetization.

Echo‐Planar Diffusion Spectroscopic Imaging
Yoshitaka Bito, Satoshi Hirata, Takayuki Nabeshima, Etsuji Yamamoto
Magnetic Resonance in Medicine, 33, 1, 69, 73, Wiley, 1995年01月
研究論文（学術雑誌）, Abstract

High‐speed diffusion spectroscopic imaging based on an echo‐planar technique is presented. A pair of diffusion gradients is applied prior to a rapidly oscillating magnetic field gradient which encodes both chemical shift and spatial information. By applying this technique to a phantom consisting of acetone and water, a diffusion spectroscopic image is obtained in about 15 min, about 64 times faster than the time required in the conventional method. The measured diffusion coefficients show good agreement with previously reported values. This kind of diffusion spectroscopic imaging is expected to provide a way to observe more specific metabolism.

[Advance of magnetic resonance spectroscopic imaging (MRSI) techniques]
Hirata S., Yoshitaka Bito, Yamamoto E.
Nippon Rinsho. Japanese Journal of Clinical Medicine, 1994年
研究論文（学術雑誌）

Neurofluidの研究動向　　　　　　　　　　　　　　　
尾藤, 映像情報Medical, 53, 14, 52, 55, 2021年, ［筆頭著者］
記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）

放射線画像診断のためのAIによる支援技術：医療現場で求められるAIの役割と今後について　　　　　　　　　　　　　　　
永尾, 白旗, 岩田, 仲山, 尾藤, 検査技術, 25, 1, 68, 75, 2020年01月

MRI構造画像と磁化率画像に基づくアルツハイマー病の診断指標　　　　　　　　　　　　　　　
佐藤 良太, 工藤 與亮, 河田 康雄, 宇土 仁木, 松島 理明, 矢部 一郎, 山口 晃典, 尾藤 良孝, 越智 久晃, 白猪 亨, Dementia Japan, 33, 4, 553, 553, 2019年10月
(一社)日本認知症学会, 日本語

人工知能による画像診断支援の高度化　　　　　　　　　　　　　　　
尾藤, 白旗, 岩田, 山口, 宮崎, 医用画像情報学会雑誌, 36, 2, 105, 108, 2019年, ［筆頭著者］
記事・総説・解説・論説等（学術雑誌）

AIによる医用画像診断支援への取組み　　　　　　　　　　　　　　　
荻野, 尾藤, 映像情報Medical, 50, 9, 64, 13, 2018年
記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）

3T MRIによる体幹部(特に上腹部)領域の検査の実際　　　　　　　　　　　　　　　
中村, 檜垣, 成田, 赤木, 松原, 神岡, 穐山, 原田, 瀧澤,尾藤, 飯田, 粟井, インナービジョン, 33, 5, 78, 80, 2018年
記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）

定量的磁化率マッピングの原理と技術動向　　　　　　　　　　　　　　　
尾藤, 白猪, 佐藤, 谷口, インナービジョン, 33, 9, 14, 16, 2018年, ［筆頭著者］
記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）

RFパルスの基礎　　　　　　　　　　　　　　　
尾藤, 日本磁気共鳴医学会雑誌, 37, 3, 64, 73, 2017年, ［筆頭著者］
記事・総説・解説・論説等（学術雑誌）

高画質拡散EPI　　　　　　　　　　　　　　　
高橋, 滝口, 瀧澤, 尾藤, 先端医療, 4, 6, 29, 31, 1997年
記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）

核磁気共鳴で高次脳機能を見る　　　　　　　　　　　　　　　
小泉, 板垣, 小野寺, 尾藤, 応用物理, 65, 796, 802, 1996年
記事・総説・解説・論説等（学術雑誌）

磁気共鳴描画法による生体機能計測　　　　　　　　　　　　　　　
尾藤, 岡島, 小泉, ぶんせき, 4, 285, 292, 1996年, ［筆頭著者］
記事・総説・解説・論説等（学術雑誌）

磁気共鳴スペクトル画像技術の進歩　　　　　　　　　　　　　　　
平田, 尾藤, 山本, 日本臨床, 52, 2473, 2482, 1994年
記事・総説・解説・論説等（学術雑誌）

MRI一問一答 : 撮像法選択と読影に“必ず"役立つ基礎知識
平井, 俊範, 工藤, 與亮, 堀, 正明, Q11,13,14,15,18節
Gakken, 2024年07月, 9784055201018, 367p, 日本語, ［分担執筆］

これでわかる拡散MRI 第3版
青木茂樹, 阿部修, 増谷佳孝, 高原太郎, 第5章3節 動物実験における拡散の適用：脳虚血
学研メディカル秀潤社, 2013年09月20日, 4780908744, 487, 日本語, ［分担執筆］

2024年10月 - 現在
日本医学放射線学会　　　　　　　　　　　　　　　

1995年05月 - 現在
International Society for Magnetic Resonance in Medicine　　　　　　　　　　　　　　　

1990年09月 - 現在
日本磁気共鳴医学会