TOHOKU UNIVERSITY Researchers - Yoshikazu Okamoto

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Yoshikazu Okamoto

Section

Graduate School of Medicine

Job title

Professor

Degree

Doctor of medicine (University of Fukuoka)

researchmap

https://researchmap.jp/7000024598

J-GLOBAL ID

201801004759540720

Profile

スポーツによる障害の予防を、少年期のアスリートから障がい者スポーツ選手まで幅広く対象に取り組んでいます。専門は画像診断学で、MRIを中心とした医用画像に、整形外科的知見およびAI・動作解析などの工学的アプローチを融合し、現場で役立つ診断支援やコンディショニング指標の開発を行っています。可搬型MRIやマーカーレスMoCapなどの先進的ツールを活用した「スポーツ現場診断学」を提唱し、実装と社会展開を見据えた研究を進めています。

Research Interests 10

Upper limb disorders in wheelchair athletes
Portable MRI and on-site sports diagnostics
Markerless motion capture (MoCap)
TFCC injury and LP lesion (elbow/wrist MRI)
AI-based risk prediction of sports injuries
Personalized diagnostic support using MRI-based AI
Para-athlete support and injury prevention
Youth athletes (Little League elbow)
Skeletal muscle MRI and recovery age scoring
Early detection of knee osteoarthritis (knee OA)

Research Areas 3

Informatics / Intelligent informatics / Pose estimation, machine learning-based medical image analysis, MRI×MoCap integration, AI for sports injury prediction
Life sciences / Sports science / On-site diagnostics in sports, injury prevention, para-sports support, markerless motion capture
Life sciences / Radiology / Diagnostic radiology, portable MRI development, MRI evaluation of elbow/wrist joints, AI applications in orthopedic disorders

Papers 91

Breast cancer classification based on the integration of diagnostic algorithms for calcifications and masses using a mixture of experts. International-journal

Yuma Konaka, Takuya Ueda, Ryusei Inamori, Jumpei Sato, Keisuke Sugawara, Yuta Shiratori, Fumihito Hario, Eichi Takaya, Tomoya Kobayashi, Yoshikazu Okamoto

PloS one　20　(9)　e0331017　2025

DOI： 10.1371/journal.pone.0331017 　

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PURPOSE: To investigate the effectiveness of an integrated deep-learning (DL) algorithm, the Mixture of Radiological Findings Specific Experts (MoRFSE), in breast cancer classification by imitating the diagnostic decision-making process of radiologists. METHODS: A total of 2,764 mammographic images (1,462 breast cancer, 248 benign lesions, and 1,054 normal breast tissue) from the TOMPEI-CMMD were used. The MoRFSE comprises three DL models: a gate network for categorization (gNet) and two classification expert networks (cExp and mExp) specialized in capturing the distinct characteristics of calcifications and masses, respectively. This structure imitates radiologists' comprehensive diagnostic process by applying distinct algorithms for different lesion types. The classification performance of MoRFSE was compared with the Conventional ResNet18 model. 5-fold cross-validation was used, and performance was assessed using the area under the receiver operating characteristic curve (AUC). DeLong's test was performed to evaluate statistical significance. RESULTS: MoRFSE achieved a significantly higher AUC (0.9616) compared to Conventional ResNet18 (0.9577, p = 0.001348). CONCLUSION: By integrating specialized algorithms for calcifications and masses, the MoRFSE model effectively emulates radiologists' diagnostic process. These findings suggest that MoRFSE has the potential to improve the accuracy of breast cancer diagnosis based on mammograms.
死後CT画像における心臓周囲脂肪のCT値の変化心肺蘇生の影響

高橋優花, 小林智哉, 小田まりや, 望月純二, 齋藤創, 田代和也, 加賀和紀, 岡本嘉一

JART: 日本診療放射線技師会誌　71　(10)　1139-1139　2024/10
Publisher: (公社)日本診療放射線技師会
ISSN： 2187-2538
Optimization of Traction Magnetic Resonance Imaging to Improve Visibility of the Elbow Cartilage

Kohyama, Sho, Ikeda, Kazuhiro, Okamoto, Yoshikazu, Ochiai, Naoyuki, Yoshii, Yuichi

Diagnostics (Basel, Switzerland)　14　(6)　2024/03

DOI： 10.3390/diagnostics14060630 　

ISSN： 2075-4418

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We previously reported that elbow magnetic resonance imaging (MRI) with 7 kg traction increases the joint space width of the radiocapitellar joint and improves articular cartilage visibility without arthrography. However, the optimal traction weight remains unclear. We assessed the effects of different traction weights on elbow MRI in 30 healthy volunteers. Elbow MRI was performed without traction and with 3, 5, and 7 kg axial tractions. The joint space width, humeral articular cartilage outline visibility, and intraprocedural pain/discomfort were evaluated. The joint and cartilage parameters were measured at the radiocapitellar joint and the lateral and medial thirds of the ulnohumeral joint. At the radiocapitellar joint, the joint space width increased significantly with traction. The cartilage outline visibility significantly increased with traction, with no significant differences among the traction weights. No significant result was observed at the lateral and medial thirds of the ulnohumeral joint. Pain and discomfort significantly increased as we used heavier traction weights. Elbow MRI with 3 kg traction showed sufficient effects similar to those observed with 7 kg traction with minimal pain and discomfort. There was no difference in the effect of traction between male and female participants. This procedure may enable enhanced visualization of intra-articular elbow injuries.
Hip and lumbosacral joint centre locations in asian population: Biases produced by existing regression equations and development of new equations

Sado, Natsuki, Edagawa, Takeshi, Fujimori, Toshihide, Hashimoto, Shogo, Okamoto, Yoshikazu, Nakajima, Takahito

JOURNAL OF BIOMECHANICS　162　111866　2023/11
Publisher: ELSEVIER SCI LTD
DOI： 10.1016/j.jbiomech.2023.111866 　

ISSN： 0021-9290

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The hip and lumbosacral joint centre (HJC and LSJC) predictions are required to analyse the lumbo-pelvic-hip dynamics during various human motions. Some HJC and LSJC regression equations based on pelvic dimension have been developed; however, the pre-existing methods need to be re-evaluated, and methodological reconsideration may improve the regression methods. Here we show that pre-existing methods produce biased predictions of the LSJC and HJC in 23 male and 24 female Japanese adults, and that the biases in the LSJC differ between sexes, using magnetic resonance imaging (MRI) around the pelvis. Compared with directly measured locations on MRI, the pre-existing regression equations predict LSJC to be more posterior in males and more inferior and posterior in females, and HJC to be more medial in both sexes. The better pre-existing regression equation for LSJC height differs between sexes, with pelvic-width-base better in males and pelvic-depth-base better in females, respectively. We suggest the unsuitability of pre-existing methods to our dataset consisting of Japanese adults and the importance of considering sex differences in regression methods. We propose regression equations to predict HJC and LSJC, considering soft-tissue thickness, sex differences, and a height-directional measure, using least absolute shrinkage and selection operator regression. We validate them using leave-one-out cross-validation (LOOCV). LOOCV shows that our model produces negligible biases and smaller absolute errors than the pre-existing regressions; in particular, the anteroposterior absolute error for LSJC is less than half that of the pre-existing regression. Our regression equation can be a powerful solution for accurate motion analysis.
Distal muscle cross-sectional area is correlated with shot put performance

Hashimoto, S, Fujimori, T, Ohyama-Byun, K, Okamoto, Y, Nakajima., T, Sado, N

JOURNAL OF BIOMECHANICS　160　111819　2023/11
Publisher: ELSEVIER SCI LTD
DOI： 10.1016/j.jbiomech.2023.111819 　

ISSN： 0021-9290

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Shot putters throw a heavy shot by "pushing". Pushing involves the coordinated extension of multiple joints and is a common motor task for both upper and lower limbs. In lower limb musculature, proximal-specific development and association with motor performance have been shown in athletes. However, as the upper limb is not mechanically loaded to support the body during daily locomotion, it may develop differently from the lower limb. We investigated the cross-sectional area of the prime movers of the upper limb and upper trunk (pectoralis major, deltoid, triceps brachii, and palmar flexors) in eleven male shot put athletes and fourteen untrained males by obtaining magnetic resonance images and manually tracing the muscles on the images. All target muscles were significantly larger in athletes than non-athletes (p < 0.01), with "huge" effect sizes for the pectoralis major and palmar flexors (d = 2.74, 2.04). All target muscle cross-sectional areas were positively correlated with season best record (r >= 0.62, p <= 0.04), with a particularly strong correlation for the palmar flexors (r = 0.96). These results suggest that the distal muscles of the upper limb are also expected to develop and are strongly associated with motor performance. This is especially true for the distal upper limb muscles (palmar flexors) in shot putters. These findings provide insight into potential training interventions for athletic performance in forceful upper limb movements.
Hip and lumbosacral joint centre locations in Asian population: biases by existing regressions and development of new methods Peer-reviewed

Sado, N, Edagawa, T, Fujimori, T, Hashimoto, S, Okamoto, Y, Nakajima, T

ISBS-Conference Proceedings Archive　41　(1)　93　2023/08
Pectoralis major and deltoid muscularity in shot putters: Reversal of whether cross-sectional area or volume is related to performance

Hashimoto, S, T., Fujimori, Edagawa T, K, Ohyama-Byun, Y., Okamoto, T., Nakajima, N., Sado

29th Congress of International Society of Biomechanics / Japanese Society of Biomechanics　306　2023/07
Unique mass distribution in the lower limbs of distance runners and its effect on moment of inertia

Edagawa T, Fujimori T, Hashimoto, S, Okamoto, Y, T., Nakajima, Sado, N

29th Congress of International Society of Biomechanics / Japanese Society of Biomechanics　295　2023/07
Advances in Bone Joint Imaging-Metal Artifact Reduction

Kohyama, Sho, Yoshii, Yuichi, Okamoto, Yoshikazu, Nakajima, Takahito

DIAGNOSTICS　12　(12)　2022/12
Publisher: MDPI
DOI： 10.3390/diagnostics12123079 　

ISSN： 2075-4418

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Numerous types of metal implants have been introduced in orthopedic surgery and are used in everyday practice. To precisely evaluate the postoperative condition of arthroplasty or trauma surgery, periprosthetic infection, and the loosening of implants, it is important to reduce artifacts induced by metal implants. In this review, we focused on technical advances in metal artifact reduction using digital tomosynthesis, computed tomography, and magnetic resonance imaging. We discussed new developments in diagnostic imaging methods and the continuous introduction of novel technologies to reduce metal artifacts; however, these innovations have not yet completely removed metal artifacts. Different algorithms need to be selected depending on the size, shape, material and implanted body parts of an implant. Future advances in metal artifact reduction algorithms and techniques and the development of new sequences may enable further reductions in metal artifacts even on original images taken previously. Moreover, the combination of different imaging modalities may contribute to further reductions in metal artifacts. Clinicians must constantly update their knowledge and work closely with radiologists to select the best diagnostic imaging method for each metal implant.
Two case reports showing a rather striking abnormal finding of unknown origin localized to the cortex of an amputated femur

Sakai, Masafumi, Mutsuzaki, Hirotaka, Shimizu, Yukiyo, Okamoto, Yoshikazu, Nakajima, Takahito

Radiology case reports　17　(12)　4874-4878　2022/12

DOI： 10.1016/j.radcr.2022.09.005 　

ISSN： 1930-0433

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MRI scans of patients who have undergone leg amputation are rarely obtained; such scans may be performed when a mass is suspected to be related to the amputation or when inflammation (infection) is suspected, but the number of such cases is not large. In this study, however, we encountered 2 very striking cases in which short-tau inversion recovery coronal images taken for different purposes coincidentally showed a diffuse high signal intensity of the residual femoral cortex on the side wearing the artificial limb. Further examination of these images revealed that the superior margins of the artificial limb cup and the abnormal signal were almost identical and that the signal was only observed in the residual femur of the side using the artificial limb, suggesting that the change was caused by artificial limb usage. Despite the difficulty in imaging-pathologic correlation because the patients were still alive, we considered that the high signal was related to the characteristic microanatomy of the bone cortex and the mechanical changes caused by the effects of artificial limb usage on the residual femur. The 2 patients have not shown any specific events since then. Thus, while the residual femoral cortex may show findings of interest, these findings do not seem to require any specific treatment.
Use of a Small Car-Mounted Magnetic Resonance Imaging System for On-Field Screening for Osteochondritis Dissecans of the Humeral Capitellum Peer-reviewed

Ikeda, Kazuhiro, Okamoto, Yoshikazu, Ogawa, Takeshi, Terada, Yasuhiko, Kajiwara, Michiru, Miyasaka, Tomoki, Michinobu, Ryuhei, Hara, Yuki, Yoshii, Yuichi, Nakajima, Takahito, Yamazaki, Masashi

DIAGNOSTICS　12　(10)　2022/10
Publisher: MDPI
DOI： 10.3390/diagnostics12102551 　

ISSN： 2075-4418

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Mobile magnetic resonance imaging (MRI) using a car is a recent advancement in imaging technology. Specifically, a car-mounted mobile MRI system is expected to be used for medical check-ups; however, this is still in the research stage. This study demonstrated the practicality of a small car-mounted mobile MRI in on-field screening for osteochondritis dissecans (OCD) of the humeral capitellum. In the primary check-up, we screened the throwing elbows of 151 young baseball players using mobile MRI and ultrasonography. We definitively diagnosed OCD at the secondary check-up using X-ray photography and computed tomography or MRI. We investigated the sensitivity and specificity of mobile MRI and ultrasonography for OCD. Six patients were diagnosed with OCD. The sensitivity was 83.3% for mobile MRI and 66.7% for ultrasonography, with specificity of 99.3% vs. 100%, respectively. One patient was detected using ultrasonography but was missed by mobile MRI due to poor imaging quality at the first medical check-up. Following this false-negative case, we replaced a damaged radio frequency coil to improve the image quality, and the mobile MRI could detect all subsequent OCD cases. Two patients were diagnosed by mobile MRI only; ultrasonography missed cases lacking subchondral bone irregularity, such as a healing case, and an early-stage case. Mobile MRI could screen for OCD from the very early stages through the healing process and is therefore a practical tool for on-field screening.
Does humeral retrotorsion affect glenohumeral rotation and stiffness of posterior shoulder in college baseball pitchers?

Yoshida Kazuya, Mukai Naoki, Okamoto Yoshikazu, Takemura Masahiro

The Journal of Physical Fitness and Sports Medicine　11　(5)　305-313　2022/09
Publisher: The Japanese Society of Physical Fitness and Sports Medicine
DOI： 10.7600/jpfsm.11.305 　

ISSN： 2186-8131

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<p>Decreased internal rotation range of motion of the dominant shoulder in baseball pitchers may be due to humeral retrotorsion and posterior shoulder tightness. Measurement of shoulder tightness is generally performed with range of motion; however, this may not be optimal for measuring posterior shoulder tightness in baseball pitchers. Joint stiffness using passive torque should also be used to assess shoulder tightness. The purpose of this study was to compare dominant and non-dominant shoulder humeral retrotorsion and shoulder tightness in baseball pitchers, and dominant and non-dominant shoulder range of motion and shoulder stiffness of the passive torque after correction based on humeral retrotorsion. Twenty-five male college baseball pitchers were included. Humeral retrotorsion, shoulder range of motion (internal rotation, external rotation, total range of motion), and passive torque during shoulder internal rotation (max torque, stiffness) of the dominant and non-dominant sides were measured. Shoulder range of motion and stiffness were corrected on each side using humeral retrotorsion. Humeral retrotorsion, external rotation range of motion, and stiffness were significantly greater on the dominant side than on the non-dominant side. Internal rotation range of motion was reduced on the dominant side compared to the non-dominant side. There were no side-to-side differences in the total range of motion, humeral retrotorsion-corrected range of motion, and humeral retrotorsion-corrected stiffness. In conclusion, healthy college baseball pitchers have decreased internal rotation range of motion in the dominant shoulder due to side-to-side differences in humeral retrotorsion, not joint stiffness.</p>
Characteristic MRI findings of the shoulder, elbow, and wrist joints in elite wheelchair basketball players

Sakai, Masafumi, Mutsuzaki, Hirotaka, Shimizu, Yukiyo, Okamoto, Yoshikazu, Nakajima, Takahito

BMC sports science, medicine & rehabilitation　14　(1)　141　2022/07/23
Publisher: Springer Science and Business Media LLC
DOI： 10.1186/s13102-022-00528-9 　

ISSN： 2052-1847

eISSN： 2052-1847

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[BACKGROUND] The health of wheelchair users' upper limbs is directly related to their quality of life. Moreover, para-sport athletes are subjected to a dual load on their upper extremities from competition and daily life, making it even more critical to maintain upper extremity health. This study aimed to investigate the characteristics of joint disorders in elite wheelchair basketball players using magnetic resonance imaging (MRI). [METHODS] We scanned MRI images of the bilateral shoulders, elbows, and wrist joints of ten elite wheelchair basketball players and ten general wheelchair users. The elite wheelchair players were athletes who underwent at our institution medical checkup of the candidates for the national team for the international women's tournament and who agreed to this research purpose. The general wheelchair players were recruited from wheelchair users in their 20s and 30s who had no daily exercise habits and who agreed to the study objectives. Two radiologists interpreted the MRI images and diagnosed the diseases of each joint. We compared the number of lesions between the two groups. We used Fisher's exact test to determine whether the lesions diagnosed by MRI wer
Effectiveness of temporal subtraction computed tomography images using deep learning in detecting vertebral bone metastases International-journal

Hoshiai, Sodai, Hanaoka, Shouhei, Masumoto, Tomohiko, Nomura, Yukihiro, Mori, Kensaku, Okamoto, Yoshikazu, Saida, Tsukasa, Ishiguro, Toshitaka, Sakai, Masafumi, Nakajima, Takahito

European journal of radiology　154　110445-110445　2022/07/20

DOI： 10.1016/j.ejrad.2022.110445 　

ISSN： 1872-7727

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[PURPOSE] To assess the clinical effectiveness of temporal subtraction computed tomography (TS CT) using deep learning to improve vertebral bone metastasis detection. [METHOD] This retrospective study used TS CT comprising bony landmark detection, bone segmentation with a multi-atlas-based method, and spatial registration of two images by a log-domain diffeomorphic Demons algorithm. Paired current and past CT images of 50 patients without vertebral metastasis, recorded during June 2011-September 2016, were included as training data. A deep learning-based method estimated registration errors and suppressed false positives. Thereafter, paired CT images of 40 cancer patients with newly developed vertebral metastases and 40 control patients without vertebral metastases were evaluated. Six board-certified radiologists and five radiology residents independently interpreted 80 paired CT images with and without TS CT. [RESULTS] Records of 40 patients in the metastasis group (median age: 64.5 years; 20 males) and 40 patients in the control group (median age: 64.0 years; 20 males) were evaluated. With TS CT, the overall figure of merit (FOM) of the board-certified radiologist and resident
Development of a Car-mounted Mobile MR Imaging System for Diagnosis of Sports-related Wrist Injury Peer-reviewed

Miyasaka, Tomoki, Kajiwara, Michiru, Kawasaki, Akito, Okamoto, Yoshikazu, Terada, Yasuhiko

Magnetic Resonance in Medical Sciences (MRMS)　22　(3)　379-387　2022/04
Publisher: JPN SOC MAGNETIC RESONANCE MEDICINE
ISSN： 1347-3182
Changes in skeletal muscle diffusion parameters owing to intramyocellular lipid International-journal Peer-reviewed

Tadano, Kiichi, Okamoto, Yoshikazu, Isobe, Tomonori, Mori, Shintaro, Suzuki, Hiroaki, Minami, Manabu, Sakae, Takeji

Magnetic resonance imaging　73　70-75　2020/11
Publisher: ELSEVIER SCIENCE INC
DOI： 10.1016/j.mri.2020.08.002 　

ISSN： 1873-5894

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[INTRODUCTION] Several studies investigated the changes in diffusion of water molecules in skeletal muscle cells of lifestyle-related-disease patients who performed a hybrid training (HYBT) for six months. They reported that the apparent diffusion coefficient (ADC) and all diffusion eigenvalues (λ, λ, and λ) increased after the HYBT, owing to the enlargement of the intramyocellular diffusion space (intracellular space) caused by the muscular hypertrophy. We assumed that the HYBT promoted metabolism of the whole skeletal muscle including lipids, which reduced the amount of intramyocellular lipid (IMCL), and led to a secondary enlargement of the diffusion space in the skeletal muscle cells. However, the IMCL has to be a diffusion limiting factor in order to verify this hypothesis. Until now, there is no report on whether IMCL is a diffusion limiting factor for water molecules. The objective of this study was to examine whether the IMCL is a diffusion limiting factor in skeletal muscle cells. [MATERIALS AND METHODS] We performed a three-dimensional quantification of the IMCL in triceps surae muscles of lifestyle-related-disease patients and healthy volunteers. In addition, we measu
Investigation of site and frequency of asymptomatic injury in medial structures of the elbow in adolescent baseball players using dedicated magnetic resonance imaging Peer-reviewed

Yoshizawa, Tomohiro, Okamoto, Yoshikazu, Makihara, Takeshi, Tanaka, Kenta, Ogawa, Takeshi, Yamazaki, Masashi

JAPANESE JOURNAL OF RADIOLOGY　39　(3)　261-266　2020/10
Publisher: SPRINGER
DOI： 10.1007/s11604-020-01048-7 　

ISSN： 1867-1071

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Purpose Medial epicondyle (ME) and elbow joint proximal (UCL-p) and distal ulnar collateral ligament (UCL-d) asymptomatic injuries are frequently observed using magnetic resonance imaging (MRI). However, the injury rates vary among these structures in elbow screening of adolescent baseball players, despite being adjacent medial structures of the elbow. This study aimed to retrospectively determine the actual injury site and rate, and investigate the underlying reason for discrepancies anatomically and biomechanically. Materials and methods Forty-four male adolescent baseball players were scanned using MRI. Two interpreters independently and retrospectively assessed the ME, UCL-p, and UCL-d injuries using the gradient echo axial, sagittal, and coronal planes. Results The injury prevalence was significantly higher in the ME and UCL-p (> 50% of the participants) than in the UCL-d (22.7%),P < 0.01 andP < 0.01, respectively. Additionally, there was a tendency toward a high-frequency injury rate of the ME or UCL-p. Conclusion The injury site of the medial structures tended to be proximal. The ME and UCL-p were observed to be more frequently injured compared to the UCL-d in adolescent baseball players according to the dedicated MRI findings in this study.
Development and screening examination of a car-mounted portable MRI for wrist Peer-reviewed

Tomoki, Miyasaka, Michiru, Kajiwara, Akito, Kawasaki, Yoshikazu, Okamoto, 寺田, 康彦

第48回日本磁気共鳴医学会大会講演抄録集　113-113　2020/09
Clinical feasibility of mobile medical screening for wrist injuries in tennis players using a small car-mounted MRI Peer-reviewed

Miyasaka, Tomoki, Kajiwara, Michiru, Kawasaki, Akito, Okamoto, Yoshikazu, Terada, Yasuhiko

Proc. Intl. Soc. Mag. Reson. Med. 28　2020/08
ポータブルMRIを用いた手首診断

宮坂, 知樹, 梶原, 成生, 川崎, 亮人, 岡本, 嘉一, 寺田, 康彦

第24回NMRマイクロイメージング研究会講演要旨集　26-29　2020/08
Characteristic MRI findings of shoulder, elbow, and wrist joints in wheelchair user International-journal Peer-reviewed

Sakai, Masafumi, Mutsuzaki, Takahiro, Shimizu, Yukiyo, Okamoto, Yoshikazu, Yatabe, Katsuhiko, Muraki, Ichio, Nakajima, Kotaro

SKELETAL RADIOLOGY　Epub　(1)　171-178　2020/07
Publisher: SPRINGER
DOI： 10.1007/s00256-020-03545-2 　

ISSN： 0364-2348

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OBJECTIVE: Wheelchair users frequently utilize their upper extremities for moving around in their daily life. Therefore, it is likely they may develop conditions of overuse in their joints, which could affect their activity and daily life. The purpose of this study is to clarify the actual conditions of the joints of wheelchair users using MRI. MATERIAL AND METHODS: Twenty-five wheelchair users and twenty able-bodied control volunteers participated in this study. We scanned MRI images of their right and left shoulders, elbows, and wrists. Two radiologists interpreted the images and made diagnoses for each of the joints. The number of diseases for each joint was compared between wheelchair users and able-bodied volunteers. RESULTS: The number of supraspinatus tendon tears was higher in wheelchair users than controls in the right (Rt.) (P < 0.05), left (Lt.) (P < 0.05), and bilateral (Bil.) (P < 0.05) shoulders. The number of elbow LP lesions (Rt. (P < 0.01), Lt. (P < 0.01), and Bil. (P < 0.05)) and the number of elbow lateral epicondylitis cases (Rt. [P < 0.05] and Lt. [P < 0.05]) were also higher in wheelchair users than that of control volunteers. Additionally, the number of wrist TFCC injuries in wheelchair users (Rt. [P < 0.01], Lt. [P < 0.01], and Bil. [P < 0.01]) was more than that of control volunteers. CONCLUSION: Our results suggest that there are several types of overuse injury in each joint. However, we hypothesize that these are not induced by driving wheelchairs, but instead by the "push up" movement characteristic for wheelchair users, according to the situations caused by each injury.
Clinical and Anthropometric Characteristics of Non-obese NAFLD Subjects in Japan Peer-reviewed

Shoda, Junichi, Shida, Takashi, Oshida, Natsumi, Suzuki, Hideo, Okada, Kosuke, Watahiki, Takahisa, Oh, Sechang, Kim, Taeho, Isobe, Tomonori, Okamoto, Yoshikazu, Ariizumi, Shun-ichi, Yamamoto, Masakazu

Hepatology Research　50　(9)　1032-1046　2020
Publisher: Willey
DOI： 10.1111/hepr.13543 　

ISSN： 1386-6346

eISSN： 1872-034X
Urinary Levels of Titin-N Fragment, a Skeletal Muscle Damage Marker, are Increased in Subjects with Nonalcoholic Fatty Liver Disease International-journal

Oshida, Natsumi, Shida, Takashi, Oh, Sechang, Kim, Taeho, Isobe, Tomonori, Okamoto, Yoshikazu, Kamimaki, Takashi, Okada, Kosuke, Suzuki, Hideo, Ariizumi, Shun-Ichi, Yamamoto, Masakazu, Shoda, Junichi

Scientific reports　9　(1)　19498-19498　2019/12
Publisher: NATURE PUBLISHING GROUP
DOI： 10.1038/s41598-019-56121-7 　

ISSN： 2045-2322

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Sarcopenia is a pathological condition affecting the development and progression of NAFLD. Urinary levels of titin-N fragment, a biomarker reflecting muscle damage, were measured in NAFLD subjects, and analyzed in a retrospective manner for possible correlations with NAFLD pathophysiology to assess their clinical relevance. This study enrolled 153 NAFLD subjects and 100 subjects without NAFLD, obesity or diabetes mellitus (non-NAFLD). NAFLD subjects had more decreased knee extension strength. NAFLD subjects had greater subcutaneous fat thickness and echo intensity (brightness) of the rectus femoris muscle on ultrasound images; higher levels of the intra- and extra-myocellular lipids (IMCL, EMCL) using H-MRS. Urinary titin-N fragment levels were increased with increasing age but not different between males and females. NAFLD subjects had higher titin-N fragment levels than non-NAFLD subjects. The levels were negatively correlated with skeletal muscle mass and knee extension strength and positively correlated with muscle echo intensity, EMCL, and liver fibrosis scores (NAFLD fibrosis score, FIB-4 index). Multivariate analysis revealed that factors affecting the levels were skeletal m
Clinical usefulness of temporal subtraction CT in detecting vertebral bone metastases. International-journal Peer-reviewed

Sodai Hoshiai, Tomohiko Masumoto, Shouhei Hanaoka, Yukihiro Nomura, Kensaku Mori, Tadashi Hara, Tsukasa Saida, Yoshikazu Okamoto, Manabu Minami

European journal of radiology　118　175-180　2019/09
Publisher: ELSEVIER IRELAND LTD
DOI： 10.1016/j.ejrad.2019.07.024 　

ISSN： 1872-7727

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PURPOSE: The purpose of this study was to determine whether temporal subtraction (TS) computed tomography (CT) contributes to the detection of vertebral bone metastases. METHOD: The calculation of TS CT was composed of bony landmark detection, bone segmentation with a multiatlas-based method, and spatial registration. Temporal increase and decrease of the CT values were visualized in blue and red, respectively. Paired CT images of 20 patients with cancer and newly-developed vertebral metastases were analyzed. Control CT examinations of 20 different patients were also included. The presence of vertebral metastases on the TS CT was evaluated by two board-certified radiologists. Five additional board-certified radiologists and five radiology residents independently interpreted the 40 paired CT images with and without TS CT. RESULTS: In the lesion conspicuity evaluation, 96% of vertebral metastases were scored as excellent or good. In the image interpretation examination, according to free-response receiver operating characteristics analysis, the overall figure of merit (FOM) of the board-certified radiologist group was 0.892 and 0.898 with and without TS CT, respectively. The FOM of the resident group improved from 0.849 to 0.902 with viewing TS CT. In the sub-analysis focusing on the location of the lesion, the FOM of the resident group significantly improved from 0.75 to 0.92 in vertebral arch lesions (p = 0.001). CONCLUSIONS: The TS CT may be useful to detect vertebral metastases because almost all the vertebral metastases were shown to be favorable visualization. The TS CT was proven to be especially helpful for radiology residents in detecting vertebral arch metastases.
Field examination of baseball elbow using a car-mounted portable MRI Peer-reviewed

梶原, 成生, 中込, 真優, 岡本, 嘉一, 寺田, 康彦

第47回日本磁気共鳴医学会大会講演抄録集　204-204　2019/09
ポータブル MRI の野球場での撮像試験

梶原, 成生, 宮坂, 知樹, 岡本, 嘉一, 寺田, 康彦

第23回NMRマイクロイメージング研究会講演要旨集　25-28日　2019/08
Change in MRI findings of medial collateral ligament injury in adolescent baseball players with no clinical symptoms over time Peer-reviewed

Makihara, Takeshi, Okamoto, Yoshikazu, Yoshizawa, Tomohiro, Tanaka, Kenta, Ogawa, Takeshi, Minami, Manabu, Yamazaki, Masashi

Skeletal radiology　48　(12)　1925-1932　2019/05
Publisher: SPRINGER
DOI： 10.1007/s00256-019-03231-y 　

ISSN： 0364-2348

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[OBJECTIVE] Elbow screening of adolescent baseball players began in 2014 using ultrasound, palpation, and dedicated magnetic resonance imaging (MRI). We frequently encountered subjects showing MCL injury on MRI but no clinical symptoms. We assessed variations in asymptomatic MCL injury findings at follow-up MRI, and clarified the pathogenesis of these findings. [MATERIALS AND METHODS] Using a 0.2-T-dedicated MRI, 30 subjects with asymptomatic MCL injury at initial MRI who agreed to follow-up MRI were included. We classified the findings at repeat MRI as follows: (a) disappeared, (b) better, and (c) worse. [RESULTS] There were 6, 16, and 8 subjects in groups a, b, and c, respectively. The average age at follow-up was 14.0, 12.1, and 12.4 years in groups a, b, and c, respectively. There were significant differences between groups a and b and between groups a and c. Average height at follow-up of groups a, b, and c was 1.64, 1.52, and 1.57 cm, respectively, with a statistically significant difference between groups a and b. The average size of the short axis of the MCL of subjects in group a was 2.0 cm on the dominant side and 1.5 cm on the contradominant side (P < 0.04). [CONCLUSION] Players with asymptomatic MCL injury can continue to play baseball with no limitations, as these findings usually disappear around the age of 14.0 years, when the growth spurt occurs. This finding may be a precursor of 'adaptation', which is generally observed in high school baseball players, suggesting that the MCL adapts as growth occurs.
Safety margin of radiofrequency ablation for hepatocellular carcinoma: a prospective study using magnetic resonance imaging with superparamagnetic iron oxide

Fukuda, Kuniaki, Mori, Kensaku, Hasegawa, Naoyuki, Nasu, Katsuhiro, Ishige, Kazunori, Okamoto, Yoshikazu, Shiigai, Masanari, Abei, Masato, Minami, Manabu, Hyodo, Ichinosuke

Japanese journal of radiology　2019/05

DOI： 10.1007/s11604-019-00843-1 　

ISSN： 1867-108X

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[PURPOSE] In radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC), it is difficult to assess the ablative margin (AM) precisely by comparing pre- and post-RFA CT images. We prospectively studied the AMs using magnetic resonance imaging (MRI) with pre-administered superparamagnetic iron oxide (SPIO). SPIO is safe for kidney disease patients. [MATERIALS AND METHODS] Hepatocellular carcinoma patients were treated with RFA within 8 h of SPIO administration. On T2*-weighted MRI performed 4-7 days later, AM was visualized as a hypointense rim. The ablation status was classified as AM(+) if the rim completely surrounded the tumor, AM(0) if the rim was partly discontinuous without tumor protrusion, and AM(-) if the rim was partly discontinuous with tumor protrusion. The minimal thickness of AM was measured. AM(-) tumors were re-treated consecutively. [RESULTS] In total, 85 HCCs ablated in 76 patients were evaluated. The local recurrence rate at 3 years was 2% for AM(+) tumors and 34% for AM(0) tumors (p < 0.01). In addition, no local recurrence was seen in the tumors with an AM of ≥ 2 mm. [CONCLUSION] MRI with pre-administered SPIO is useful for determining the AM precisely, and an AM of ≥ 2 mm is recommended for curative RFA. [TRIAL REGISTRATION NUMBER] This study was registered with UMIN Clinical Trials Registry (UMIN 000025406).
Whole-body vibration for patients with nonalcoholic fatty liver disease: a 6-month prospective study

Oh, Sechang, Oshida, Natsumi, Someya, Noriko, Maruyama, Tsuyoshi, Isobe, Tomonori, Okamoto, Yoshikazu, Kim, Taeho, Kim, Bokun, Shoda, Junichi

Physiological reports　7　(9)　2019/04/01
Publisher: WILEY
DOI： 10.14814/phy2.14062 　

ISSN： 2051-817X

eISSN： 2051-817X
Development of a small car-mounted magnetic resonance imaging system for human elbows using a 0.2 T permanent magnet

Nakagomi, Mayu, Kajiwara, Michiru, Matsuzaki, Jumpei, Tanabe, Katsumasa, Hoshiai, Sodai, Okamoto, Yoshikazu, Terada, Yasuhiko

Journal of Magnetic Resonance　304　1-6　2019/04
Publisher: ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI： 10.1016/j.jmr.2019.04.017 　

ISSN： 1090-7807

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Portable magnetic resonance imaging (MRI) scanners can provide opportunities for mobile operation in many environments including disease screening and primary care suites. Here, we develop a new, compact transportable MRI system for imaging small joints of the extremities using a 0.2 T, 200 kg permanent magnet. The whole system, including the magnet, gradient coils, RF probes, and MRI consoles (80 kg in weight) was installed in a standard-size minivan-style vehicle. The use of the open-geometry magnet enables easy patient positioning within the limited space of the vehicle. We show that our portable MRI system provides clinically relevant images of screening for elbow injuries induced by overuse of overhand throwing. This transportable system is deployable during sport events or in environments with poor access to MRI systems, and could be applicable for mass screening, early diagnosis, and case finding.
Three-dimensional MRI analyses of prereduced femoral head sphericity in patients with developmental dysplasia of the hip after Pavlik harness failure Peer-reviewed

Tsukagoshi, Yuta, Kamada, Hiroshi, Takeuchi, Ryoko, Nakagawa, Shogo, Tomaru, Yohei, Kamegaya, Makoto, Nishino, Tomofumi, Okamoto, Yoshikazu, Mishima, Hajime, Yamazaki, Masashi

Journal of pediatric orthopedics. Part B　27　(5)　394-398　2018/09
Publisher: LIPPINCOTT WILLIAMS & WILKINS
DOI： 10.1097/BPB.0000000000000494 　

ISSN： 1060-152X

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We used three-dimensional (3D) MRI to assess the sphericity of the cartilaginous femoral head in developmental dysplasia of the hip. We assessed 21 children using 3D-MRI. The smallest sphere including the femoral head cartilage was drawn, the diameter was measured, and the center of the sphere was defined. We compared the diameters of the femoral heads between unaffected and diseased sides. The diameter of the affected side was smaller, with flattening at the posteromedial area and proximoposterior areas. 3D-MRI showed that the shape of the dislocated femoral head was aspherical with focal growth failure.
Deep convolutional neural network for denoising images of low-field scanners

中込, 真優, 田辺, 亮勝, 星合, 壮大, 岡本, 嘉一, 寺田, 康彦

第46回日本磁気共鳴医学会大会雑誌　252-252　2018/09
Development of portable MRI for detection of baseball elbow (3)

中込, 真優, 田辺, 亮勝, 巨瀬, 勝美, 岡本, 嘉一, 星合, 壮大, 寺田, 康彦

第46回日本磁気共鳴医学会大会雑誌　184-184　2018/09
永久磁石 MRI における深層学習を用いたノイズ除去の検討

寺田, 康彦, 中込, 真優, 岡本, 嘉一

第22回NMRマクロイメージング研究会抄録集　47-50　2018/08
Development of a small-car mountable MRI system for human extremities using a 0.2 T permanent magnet.

Tanabe, Katsumasa, Nakagomi, Mayu, Kose, Katsumi, Okamoto, Yoshikazu, Hoshiai, Sodai, Terada, Yasuhiko

27th Annual Meeting & Exhibition (ISMRM) Book of Abstracts　2018/06
Image denoising with deep transfer learning for screening baseball elbow injuries using portable scanners

Nakagomi, Mayu, Hoshiai, Sodai, Okamoto, Yoshikazu, Terada, Yasuhiko

28th Annual Meeting & Exhibition (ISMRM) Book of Abstracts　2018/05
Skeletal muscle mass to visceral fat area ratio is an important determinant affecting hepatic conditions of non-alcoholic fatty liver disease

Takashi Shida, Kentaro Akiyama, Sechang Oh, Akemi Sawai, Tomonori Isobe, Yoshikazu Okamoto, Kazunori Ishige, Yuji Mizokami, Kenji Yamagata, Kojiro Onizawa, Hironori Tanaka, Hiroko Iijima, Junichi Shoda

Journal of Gastroenterology　53　(4)　535-547　2018/04/01
Publisher: Springer Tokyo
DOI： 10.1007/s00535-017-1377-3 　

ISSN： 1435-5922 0944-1174

eISSN： 1435-5922
Normal imaging laterality on magnetic resonance imaging of the medial epicondyle of the elbow on the dominant side of adolescent male baseball players

Yoshizawa, Tomohiro, Okamoto, Yoshikazu, Tanaka, Kenta, Makihara, Takeshi, Tonoe, Tomoko, Minami, Manabu, Yamazaki, Masashi

Skeletal radiology　47　(9)　1237-1244　2018/03
Publisher: SPRINGER
DOI： 10.1007/s00256-018-2921-9 　

ISSN： 1432-2161
野球肘診断用ポータブル MRI の開発

田辺亮勝, 岡本, 嘉一, 巨瀬勝美, Terada, Yasuhiko

第２１回ＮＭＲマイクロイメージング研究会要旨集　9-12　2017/08
野球肘診断用ポータブル MRI におけるシングルオブリーク機能付きシーケンスジェネレーターの開発

中込真優, 田辺亮勝, 岡本, 嘉一, 巨瀬勝美, Terada, Yasuhiko

第２１回ＮＭＲマイクロイメージング研究会要旨集　59-62　2017/08
Development of portable MRI for early detection of baseball elbow.

Tanabe, Katsumasa, Kose, Katsumi, Terada, Yasuhiko, Okamoto, Yoshikazu

14th International Conference on Magnetic Resonance Microscopy　2017/08
Clinical interpretation of asymptomatic medial collateral ligament injury observed on magnetic resonance imaging in adolescent baseball players

Kenta Tanaka, Yoshikazu Okamoto, Takeshi Makihara, Kiyoshi Maehara, Tomohiro Yoshizawa, Manabu Minami, Masashi Yamazaki

Japanese Journal of Radiology　35　(6)　319-326　2017/06/01
Publisher: Springer Tokyo
DOI： 10.1007/s11604-017-0636-9 　

ISSN： 1867-108X 1867-1071
体組成異常が非アルコール性脂肪性肝疾患(NAFLD)の肝病態に及す影響

志田隆史, 押田夏海, 秋山健太郎, 呉世昶, 磯辺智範, 岡本嘉一, 正田純一

日本消化器病学会雑誌　114　(臨増総会)　A310-A310　2017/03
Publisher: (一財)日本消化器病学会
ISSN： 0446-6586

eISSN： 1349-7693
High-Intensity Aerobic Exercise Improves Both Hepatic Fat Content and Stiffness in Sedentary Obese Men with Nonalcoholic Fatty Liver Disease Peer-reviewed

Sechang Oh, Rina So, Takashi Shida, Tomoaki Matsuo, Bokun Kim, Kentaro Akiyama, Tomonori Isobe, Yoshikazu Okamoto, Kiyoji Tanaka, Junichi Shoda

SCIENTIFIC REPORTS　7　1-12　2017/02

DOI： 10.1038/srep43029 　

ISSN： 2045-2322
Endoleak detection after endovascular aneurysm repair using unenhanced MRI with flow suppression technique: Feasibility study in comparison with contrast-enhanced CT Peer-reviewed

Mori, Kensaku, Saida, Tsukasa, Sato, Fujio, Uchikawa, Yoko, Konishi, Takahiro, Ishiguro, Toshitaka, Hiyama, Takashi, Hoshiai, Sodai, Okamoto, Yoshikazu, Nasu, Katsuhiro, Minami, Manabu

EUROPEAN RADIOLOGY　27　(1)　336-344　2017/01

DOI： 10.1007/s00330-016-4315-5 　

ISSN： 0938-7994

eISSN： 1432-1084
Endoleak detection after endovascular aneurysm repair using unenhanced MRI with flow suppression technique: Feasibility study in comparison with contrast-enhanced CT

Kensaku Mori, Tsukasa Saida, Fujio Sato, Yoko Uchikawa, Takahiro Konishi, Toshitaka Ishiguro, Takashi Hiyama, Sodai Hoshiai, Yoshikazu Okamoto, Katsuhiro Nasu, Manabu Minami

European Radiology　27　(1)　336-344　2017/01/01
Publisher: Springer Verlag
DOI： 10.1007/s00330-016-4315-5 　

ISSN： 1432-1084 0938-7994
学童期野球選手における野球肘の発症要因となる投球動作

金堀, 哲也, 岡本, 嘉一, 小倉, 圭, 前原, 淳, 島田, 一志

Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings　68　(0)　217_2-217_2　2017
Publisher: Japan Society of Physical Education, Health and Sport Sciences
DOI： 10.20693/jspehss.68.217_2 　

ISSN： 2424-1946

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<p> 成長期の野球選手における野球肘の有病率は非常に高く、野球肘の早期発見および予防の重要性が提言されている。野球肘の発症要因には酷使をはじめとして、ポジションや投球動作など、様々な要因が複雑に絡み合っている。Okamoto et al.（2016）は、学童期野球選手を対象にMRI診断を行った結果、41.9％に異常所見がみられたものの、投球数、投球頻度、ポジションとの関係性はなかったと報告している。すなわち、野球肘の発症要因において、投球動作との関連性は少なくないと考えられる。そこで本研究は、肩・肘に痛みのない学童期野球選手60名を対象に、肘関節MRI診断および投球動作の３次元動作解析を併用することで、MRI診断結果と投球動作の関係性について検討し、野球肘の発症要因となる投球動作を明らかにすることを目的とした。その結果、踏出足着地時の投球腕肩関節の外転角度においてMRI陰性群のほうが有意に小さかった。また、踏出足着地時の肩と腰の回転角度の差においてMRI陰性群のほうが有意に大きかった。以上のことから、踏出足着地時の姿勢がその後の投球腕の動作に影響を及ぼし、肘関節への過度な負荷を加えている可能性が示唆された。</p>
NAFLDにおけるCEUSを用いたKupffer細胞機能評価

長岡亜実, 志田隆史, 秋山健太郎, 磯辺智範, 岡本嘉一, 上牧隆, 正田純一

超音波検査技術　41　(6)　691-691　2016/12
Publisher: (一社)日本超音波検査学会
ISSN： 1881-4506

eISSN： 1881-4514
日常診療で放射線診断医が遭遇する代謝性骨疾患 Peer-reviewed

石黒聡尚, 小熊栄二, 細川崇洋, 岡本嘉一, 南, 学

臨床画像　32　(12)　1353-1363　2016/12
Development of portable MRI for early detection of baseball elbow

田辺, 亮勝, 岡, 修平, 岡本嘉一, Kose, Katsumi, 寺田, 康彦

第４４回日本磁気共鳴医学会大会抄録集　269-269　2016/09
無症候学童期野球選手における投球側肘内側側副靱帯損傷とadaptation 11ヵ月MRI追跡調査

牧原武史, 岡本嘉一, 田中健太, 吉沢知弘, 前原淳, 遠江朋子, 金堀哲也, 小倉圭, 井汲彰, 山崎正志, 宮川俊平

JOSKAS　41　(4)　211-211　2016/07
Publisher: (一社)日本関節鏡・膝・スポーツ整形外科学会
ISSN： 1884-8842
NAFLD診断における肝の脂肪量と線維化の評価.

磯辺智範, 岡本嘉一, 平野雄二, 正田純一

月間インナービジョン　31　(6)　102-103　2016/06
超音波を用いた非アルコール性脂肪性肝疾患における骨格筋異常の解析

志田隆史, 丸山剛, 呉世昶, 秋山健太郎, 澤井朱美, 福元喜啓, 磯辺智範, 平野雄二, 岡本嘉一, 正田純一

超音波医学　43　(Suppl.)　S746-S746　2016/04
Publisher: (公社)日本超音波医学会
ISSN： 1346-1176

eISSN： 1881-9311
Incidence of elbow injuries in adolescent baseball players: screening by a low field magnetic resonance imaging system specialized for small joints Peer-reviewed

Yoshikazu Okamoto, Kiyoshi Maehara, Tetsuya Kanahori, Takashi Hiyama, Takashi Kawamura, Manabu Minami

Japanese Journal of Radiology　34　(4)　300-306　2016/04/01
Publisher: Springer Tokyo
DOI： 10.1007/s11604-016-0526-6 　

ISSN： 1867-108X 1867-1071
Effect of biological factors on successful measurements with skeletal-muscle H-1-MRS

Tomonori Isobe, Yoshikazu Okamoto, Yuji Hirano, Hiroki Ando, Kenta Takada, Eisuke Sato, Kazuya Shinoda, Kiichi Tadano, Hideyuki Takei, Satoshi Kamizawa, Yutaro Mori, Hiroaki Suzuki

THERAPEUTICS AND CLINICAL RISK MANAGEMENT　12　1133-1137　2016

DOI： 10.2147/TCRM.S84371 　

ISSN： 1178-203X
FibroScan502の肝脂肪量測定による非アルコール性脂肪性肝疾患の非侵襲的診断法の有用性について

磯辺,智範, 志田隆史, 磯辺智範, 呉世昶, 上牧隆, 岡本嘉一, 安藤浩樹, 正田純一

超音波検査技術　40　167-173　2015/03
非アルコール性脂肪性肝疾患に対する3次元加速度トレーニングの効果

丸山剛, 呉世昶, 佐治朱美, 染谷典子, 志田隆史, 新井恵美, 磯辺智範, 岡本嘉一, 正田純一

体力科学　64　(1)　214-214　2015/02
Publisher: (一社)日本体力医学会
ISSN： 0039-906X

eISSN： 1881-4751
Therapeutic effect of hybrid training of voluntary and electrical muscle contractions in middle-aged obese women with nonalcoholic fatty liver disease: a pilot trial

Sechang Oh, Tsuyoshi Maruyama, Kiyoshi Eguchi, Takashi Shida, Emi Arai, Tomonori Isobe, Yoshikazu Okamoto, Junichi Shoda

THERAPEUTICS AND CLINICAL RISK MANAGEMENT　11　371-380　2015

DOI： 10.2147/TCRM.S75109 　

ISSN： 1178-203X
Controlled Attenuation Parameterの肝脂肪量測定による非アルコール性脂肪性肝疾患の非侵襲的診断法の有用性について

志田,隆史, 磯辺,智範, 呉,世昶, 上牧,隆, 岡本,嘉一, 安藤,浩樹, 正田,純一

Japanese Journal of Medical Ultrasound Technology　40　(2)　167-173　2015
Publisher: Japanese Society of Sonographers
ISSN： 1881-4506

eISSN： 1881-4514

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目的：超音波検査は脂肪肝の検出に優れたモダリティであるが，肝脂肪化を定量的に評価することは困難である．近年，Controlled Attenuation Parameter (CAP) を用いることで肝脂肪量の定量化が可能となった．今回は，非アルコール性脂肪性肝疾患 (non-alcoholic fatty liver disease: NAFLD) の診断および治療におけるCAPの有用性について検討した．対象と方法：対象は，診療ガイドライン (J Gastroenterol Hepatol 2007) にてNAFLDと診断した患者110名，対照者として肝疾患を有さない者28名の計138名とした．CAPはFibroScan 502にて測定した．CAP，血液生化学検査，体組成の測定値について対比した．さらに，中年肥満男性51名の減量療法の前後におけるCAP値と体組成の変化を対比した．結果と考察：CAPにより測定した肝脂肪量は，NAFLD患者は対照者より有意に高値であった (p<0.01)．NAFLD患者と対照者のCAP値による肝脂肪化度のステージ分類は，NAFLD患者でS0: 15%，S1: 16%，S2: 32%，S3: 37%，対照者でS0: 100%, S1: 0%, S2: 0%, S3: 0%であった
大学野球選手の内野ノック守備における動作パターン Peer-reviewed

金堀哲也, 川村,卓, 岡本嘉一, 小倉圭

The Journal of Coaching Studies　29　(1)　23-29　2015
Publisher: The Japan Society of Coaching Studies
Changes in diffusion tensor imaging (DTI) eigenvalues of skeletal muscle due to hybrid exercise training

Yoshikazu Okamoto, Graham J. Kemp, Tomonori Isobe, Eisuke Sato, Yuji Hirano, Junichi Shoda, Manabu Minami

MAGNETIC RESONANCE IMAGING　32　(10)　1297-1300　2014/12

DOI： 10.1016/j.mri.2014.07.002 　

ISSN： 0730-725X

eISSN： 1873-5894
NAFLDを有する肥満者に対する加速度トレーニングの臨床的有用性

澤井朱美, 岡本嘉一, 白木仁, 田中喜代次

日本臨床スポーツ医学会誌　22　(4)　S202-S202　2014/10
Publisher: (一社)日本臨床スポーツ医学会
ISSN： 1346-4159

eISSN： 2758-3767
初発時に骨融解がみられた小児急性リンパ性白血病の1例

大黒,春夏, 小林,千恵, 玉井,香菜, 酒井,愛子, 鈴木,涼子, 福島,紘子, 福島,敬, 杉原,誠人, 岡本,嘉一, 須磨崎,亮

The Journal of the Japan Pediatric Society　118　(3)　540　2014/03
Publisher: 日本小児科学会
ISSN： 0001-6543
A cceleration training for managing nonalcoholic fatty liver disease: a pilot study Peer-reviewed

Sechang Oh, Takashi Shida, Akemi Sawai, Tsuyoshi Maruyama, Kiyoshi Eguchi, Tomonori Isobe, Yoshikazu Okamoto, Noriko Someya, Kiyoji Tanaka, Emi Arai, Akiko Tozawa, Junichi Shoda

THERAPEUTICS AND CLINICAL RISK MANAGEMENT　10　925-936　2014

DOI： 10.2147/TCRM.S68322 　

ISSN： 1178-203X
骨格筋のMRI

岡本嘉一, 磯辺,智範, 平野雄二

映像情報メディカル　46　(14)　71-78　2014
【小児整形外科疾患診断・治療の進歩】診断・評価の進歩 MRI 発育性股関節形成不全における三次元MRIを用いた三次元的評価

鎌田,浩史, 竹内,亮子, 中川,将吾, 三島,初, 坂根,正孝, 山崎,正志, 落合,直之, 岡本,嘉一

別冊整形外科　(64)　11-17　2013/10

ISSN： 0287-1645
FibroScanの肝脂肪量測定によるNAFLDの非侵襲的診断法

志田隆史, 上牧隆, 磯辺智範, 岡本嘉一, 正田純一

超音波検査技術　38　(Suppl.)　S109-S109　2013/06
Publisher: (一社)日本超音波検査学会
ISSN： 1881-4506

eISSN： 1881-4514
非アルコール性脂肪性肝疾患におけるControlled Attenuation Parameterの有用性の検討

志田隆史, 磯辺智範, 岡本嘉一, 上牧隆, 正田純一

超音波医学　40　(Suppl.)　S696-S696　2013/04
Publisher: (公社)日本超音波医学会
ISSN： 1346-1176

eISSN： 1881-9311
非アルコール性脂肪性肝疾患(NAFLD)における非侵襲的な病態評価のための新しいツール Proton MRSとFibroscan

磯辺智範, 岡本嘉一, 平野雄二, 志田隆史, 小野塚太郎, 高田健太, 正田純一

日本消化器病学会雑誌　110　(臨増総会)　A237-A237　2013/02
Publisher: (一財)日本消化器病学会
ISSN： 0446-6586

eISSN： 1349-7693
Correlation between pennation angle and image quality of skeletal muscle fibre tractography using deterministic diffusion tensor imaging Peer-reviewed

Yoshikazu Okamoto, Toru Okamoto, Yuka Kujiraoka, Yuji Hirano, Tomonori Isobe, Manabu Minami

JOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY　56　(6)　622-627　2012/12

DOI： 10.1111/j.1754-9485.2012.02450.x 　

ISSN： 1754-9477
非アルコール性脂肪性肝疾患における1H-MRSとFibroscanによる異所性脂肪の非侵襲的診断と病態評価

磯辺智範, 岡本嘉一, 正田純一

肝臓　53　(Supplement(3))　A869-A869　2012/12
IVIMを用いた骨格筋perfusion間接測定の試み

磯辺智範, 岡本嘉一, 平野雄二, 小原真, 森慎太郎, 安藤浩樹, 佐藤英介

日本磁気共鳴医学会雑誌　32　(SUPPLEMENT)　2012/09

ISSN： 0914-9457
骨格筋DTIの再現性評価

篠田和哉, 磯辺智範, 岡本嘉一, 加藤雄一, 森慎太郎, 宮本勝美

Proceedings of the 104 Scientific Meeting of JSMP　237-238　2012/09
Publisher: Japanese Society of Medical Physics
ISSN： 1345-5362
Diffusion property differences of the lower leg musculature between athletes and non-athletes using 1.5T MRI Peer-reviewed

Yoshikazu Okamoto, Shintaro Mori, Yuka Kujiraoka, Katsuhiro Nasu, Yuji Hirano, Manabu Minami

MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE　25　(4)　277-284　2012/08

DOI： 10.1007/s10334-011-0294-3 　

ISSN： 0968-5243
非アルコール性脂肪性肝疾患（NAFLD）における骨格筋脂肪化が肝病態へ及ぼす影響.

岡本嘉一, 磯辺智範, 小野塚太郎, 志田隆史, 池田瑛, 南学, 正田純一

第49回日本肝臓学会総会講演要旨　2012/06
Correlation of Histopathology With Magnetic Resonance Imaging in Kienbock Disease Peer-reviewed

Takeshi Ogawa, Yasumasa Nishiura, Yuki Hara, Yoshikazu Okamoto, Naoyuki Ochiai

JOURNAL OF HAND SURGERY-AMERICAN VOLUME　37A　(1)　83-89　2012/01

DOI： 10.1016/j.jhsa.2011.09.027 　

ISSN： 0363-5023
Evaluation of Activity, Making Diagnosis and Prediction of Future Bone Destruction by Using Low Field Compact Magnetic Resonance Imaging Machine in Patients with Rheumatoid Arthritis Peer-reviewed

Sugihara, Makoto, Suzuki, Takeshi, Okamoto, Yoshikazu, Horikoshi, Masanobu, Yokosawa, Masahiro, Hagiwara, Shinya, Hirota, Tomoya, Takano, Yohei, Umeda, Naoto, Kondo, Yuya, Tsuboi, Hiroto, Ogishima, Hiroshi, Hayashi, Taichi, Chino, Yusuke, Goto, Daisuke, Matsumoto, Isao, Sumida, Takayuki

ARTHRITIS AND RHEUMATISM　63　(10::Suppl. S)　947-S371　2011/10

ISSN： 0004-3591
New low-field extremity MRI, compacTscan: comparison with whole-body 1.5 T conventional MRI Peer-reviewed

Takeshi Suzuki, Satoshi Ito, Shinya Handa, Katsumi Kose, Yoshikazu Okamoto, Manabu Minami, Makoto Sugihara, Masanobu Horikoshi, Hiroto Tsuboi, Taichi Hayashi, Daisuke Goto, Isao Matsumoto, Takayuki Sumida

MODERN RHEUMATOLOGY　20　(4)　331-336　2010/08

DOI： 10.1007/s10165-010-0282-x 　

ISSN： 1439-7595

eISSN： 1439-7609
3.0Tにおける下腿筋DTIの最適パラメータの検討

平野雄二, 只野喜一, 磯辺智範, 新藤雅司, 岩坂明美, 絹村瑛実, 岡本嘉一

日本放射線技術学会総会学術大会予稿集　66回　325-325　2010/02
Publisher: (公社)日本放射線技術学会
ISSN： 1884-7846
3.0T MRIを用いた下腿筋1H-MRSのデータ取得条件の検討

磯辺智範, 平野雄二, 只野喜一, 森慎太郎, 宮田真理子, 山田功二, 岡本嘉一

日本放射線技術学会総会学術大会予稿集　66回　326-326　2010/02
Publisher: (公社)日本放射線技術学会
ISSN： 1884-7846
Changes in MR Diffusion Properties during Active Muscle Contraction in the Calf Peer-reviewed

Yoshikazu Okamoto, Akira Kunimatsu, Tatsuo Kono, Katsuhiro Nasu, Junichi Sonobe, Manabu Minami

MAGNETIC RESONANCE IN MEDICAL SCIENCES　9　(1)　1-8　2010

ISSN： 1347-3182
Gender Differences in MR Muscle Tractography

Yoshikazu Okamoto, Akira Kunimatsu, Tatsuo Kono, Yuka Kujiraoka, Jyunichi Sonobe, Manabu Minami

MAGNETIC RESONANCE IN MEDICAL SCIENCES　9　(3)　111-118　2010

ISSN： 1347-3182
A new low-field extremity magnetic resonance imaging and proposed compact MRI score: evaluation of anti-tumor necrosis factor biologics on rheumatoid arthritis Peer-reviewed

Takeshi Suzuki, Satoshi Ito, Shinya Handa, Katsumi Kose, Yoshikazu Okamoto, Manabu Minami, Taichi Hayashi, Daisuke Goto, Isao Matsumoto, Takayuki Sumida

MODERN RHEUMATOLOGY　19　(4)　358-365　2009/08

DOI： 10.1007/s10165-009-0172-2 　

ISSN： 1439-7595

eISSN： 1439-7609
Radiofrequency Ablation of the Liver: Determination of Ablative Margin at MR Imaging with Impaired Clearance of Ferucarbotran-Feasibility Study Peer-reviewed

Kensaku Mori, Kuniaki Fukuda, Hitoshi Asaoka, Takuya Ueda, Akira Kunimatsu, Yoshikazu Okamoto, Katsuhiro Nasu, Kiyoshi Fukunaga, Yukio Morishita, Manabu Minami

RADIOLOGY　251　(2)　557-565　2009/05

DOI： 10.1148/radiol.2512081161 　

ISSN： 0033-8419
Magnetic resonance microscopy imaging of posterior interosseous nerve palsy

Toshihiro Furuta, Yoshikazu Okamoto, Eriko Tohno, Manabu Minami, Yasumasa Nishiura, Kuni Ohtomo

Japanese Journal of Radiology　27　(1)　41-44　2009/01
Publisher: SPRINGER
DOI： 10.1007/s11604-008-0290-3 　

ISSN： 1867-1071 1867-108X

eISSN： 1867-108X
Comparison of tumor regression rate of uterine cervical squamous cell carcinoma during external beam and intracavitary radiotherapy Peer-reviewed

Ohara, Kiyoshi, Tanaka, Yumiko Oishi, Oki, Akinori, Okamoto, Yoshikazu, Satoh, Toyomi, Matsumoto, Koji, Yoshikawa, Hiroyuki

RADIATION MEDICINE　26　(9)　526-532　2008/11
Publisher: SPRINGER
DOI： 10.1007/s11604-008-0268-1 　

ISSN： 1862-5274

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Purpose. We compared the radioresponse of cervical carcinoma that was closely related to local disease control by the tumor regression rate (RR) during intracavitary radiotherapy (ICRT) and external beam radiotherapy (EBRT) on the presumption that ICRT has a stronger treatment impact than EBRT because of its specific dose distribution. Materials and methods. A total of 37 patients were treated by EBRT at 45.0 Gy over 5 weeks, followed by high-dose-rate ICRT at 6.0 Gy per weekly insertion at point A three to five times and by boost EBRT. RR was defined as the slope (day-1) of the tumor-volume shrinkage curve fit to an exponential regression equation. Assuming that the tumors were ellipsoid, the tumor volume was estimated using magnetic resonance (MR) images obtained before treatment, after 45.0 Gy of EBRT, and after the third ICRT insertion. RRs were compared based on the radiotherapy method. Results. RR ranged between -0.008 to 0.093 day(-1) (median 0.021 day(-1)) during EBRT and -0.001 to 0.097 day(-1) (median 0.018 day(-1)) during ICRT, showing no significant difference or correlation between treatments. Conclusion. Contrary to expectations, RR did not directly relate to the impact of physical treatment. RR could be related to biological factors, such as the amount of tumor clearance and changes in tumor consistency during treatment.
Fractional Anisotropy Values of Calf Muscles in Normative State after Exercise : Preliminary Results

OKAMOTO, Yoshikazu, KUNIMATSU, Akira, MIKI, Soichiro, SHINDO, Masashi, NIITSU, Mamoru, MINAMI, Manabu

Magnetic Resonance in Medical Sciences　7　(3)　157-162　2008/09
Publisher: Japanese Society for Magnetic Resonance in Medicine
ISSN： 1347-3182

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Purpose: We measured fractional anisotropy (FA) of calf muscles from diffusion tensor (DT) images from simultaneous scanning of bilateral calves and determined changes in values after unilateral exercise loading. Method: We obtained DT images of both calves of 10 healthy male volunteers and measured FA of the anterior tibialis, gastrocnemius, and soleus muscles. Two of the ten were subjected to loaded exercise in their right calves; we recorded FA values immediately after exercise and 24 hours, 72 hours, and 1 week later. Results: At rest, the mean FA values of the 20 calves were 0.63±0.02 in the anterior tibialis, 0.56±0.05 in the gastrocnemius, and 0.57±0.04 in the soleus muscles. The differences were statistically significant (P<0.001) by analysis of variance (ANOVA), and differences between anterior tibialis and gastrocnemius (corrected P<0.01) and anterior tibialis and soleus (corrected P<0.01) muscles were significant by Bonferroni post hoc test. The FA values of the exercise-loaded soleus and gastrocnemius muscles of the 2 volunteers decreased just after exercise but gradually recovered to the baseline after one week. Conclusion: Our method may be useful for assessing minimal muscle damage related to muscle fatigue.
Multifocal peripheral nerve involvement associated with multiple myeloma

Yoshikazu Okamoto, Manabu Minami, Eriko Tohno, Izumi Anno, Akira Kunimatshu, Takuya Ueda

SKELETAL RADIOLOGY　36　(12)　1191-1193　2007/12

DOI： 10.1007/s00256-007-0353-z 　

ISSN： 0364-2348
Extraskeletal mesenchymal chondrosarcoma of the cervical meninx Peer-reviewed

Yoshikazu Okamoto, Manabu Minami, Takuya Ueda, Yukinari Inadome, Masaki Tatsumura, Masataka Sakane

Radiation Medicine - Medical Imaging and Radiation Oncology　25　(7)　355-358　2007/08

DOI： 10.1007/s11604-007-0144-4 　

ISSN： 0288-2043 1862-5274
Malignant or borderline mucinous cystic neoplasms have a larger number of loculi than mucinous cystadenoma: A retrospective study with MR Peer-reviewed

Yoshikazu Okamoto, Yumiko O. Tanaka, Hajime Tsunoda, Hiroyuki Yoshikawa, Manabu Minami

JOURNAL OF MAGNETIC RESONANCE IMAGING　26　(1)　94-99　2007/07

DOI： 10.1002/jmri.20948 　

ISSN： 1053-1807
MR imaging of the uterine cervix: imaging-pathologic correlation Peer-reviewed

Okamoto, Yoshikazu, Tanaka, Yumiko O, Nishida, Masato, Tsunoda, Hajime, Yoshikawa, Hiroyuki, Itai, Yuji

Radiographics : a review publication of the Radiological Society of North America, Inc　23　(2)　425-45; quiz 534-5-445　2003

DOI： 10.1148/rg.232025065 　

ISSN： 0271-5333

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Misc. 15

0.2TMRI画像を用いた小児の肘内側側副靱帯の同定におけるAIモデルの精度検証

稲森瑠星, 小林智哉, 小林智哉, 高屋英知, 高屋英知, 岡本嘉一, 岡本嘉一

日本メディカルAI学会学術集会プログラム・抄録集　7th　2025
U-Netを用いた0.2T肘MRI画像におけるデノイズ性能の検証:損失関数とResidual Blockによる検討

稲森瑠星, 小林智哉, 小林智哉, 高屋英知, 高屋英知, 岡本嘉一, 岡本嘉一

日本メディカルAI学会学術集会プログラム・抄録集　7th　2025
心臓MRI画像を用いた3DセグメンテーションにおけるSuPreMの有用性の検証

稲森瑠星, 小林智哉, 小林智哉, 高屋英知, 高屋英知, 岡本嘉一, 岡本嘉一

日本メディカルAI学会学術集会プログラム・抄録集　7th　2025
先天性股関節脱臼整復後の3D-MRIを用いた大腿骨頭真球性評価

塚越祐太, 鎌田浩史, 竹内亮子, 中川将吾, 都丸洋平, 三島初, 西野衆文, 岡本嘉一, 亀ヶ谷真琴, 山崎正志

日本整形外科学会雑誌　90　(8)　S1822-S1822　2016/08
Publisher: (公社)日本整形外科学会
ISSN： 0021-5325
野球肘のMRIによる検診の試み

岡本嘉一, 前原淳

日本臨床スポーツ医学会誌　22　(4)　2014

ISSN： 1346-4159
非アルコール性脂肪性肝疾患における中高度肥満と糖尿病が肝病態に及す影響と病態関連因子の解析

志田隆史, 小野塚太郎, 呉世昶, 磯辺智範, 岡本嘉一, 矢藤繁, 島野仁, 正田純一

肝臓　55　(Supplement 1)　2014

ISSN： 0451-4203
3DMRIにより描出した先天性股関節脱臼における関節唇

鎌田浩史, 竹内亮子, 三島初, 落合直之, 岡本嘉一, 磯辺智範, 高田健太, 平野雄二, 坂根正孝

日本シミュレーション外科学会会誌　20　(3)　54-55　2012/11
Publisher: 日本シミュレーション外科学会
ISSN： 1348-6918
骨格筋微小循環の定量評価の試み

平野雄二, 岡本嘉一, 磯辺智範, 森慎太郎, 安藤浩樹, 佐藤英介, 新藤雅司, 横田浩

日本放射線技術学会雑誌　68　(9)　1180-1180　2012/09/20
Publisher: (公社)日本放射線技術学会
ISSN： 0369-4305
骨格筋proton MRSにおけるデータ取得成功率に影響を及ぼす生体因子

磯辺智範, 岡本嘉一, 平野雄二, 佐藤英介, 安藤浩樹, 森慎太郎, 篠田和哉, 森祐太郎

医学物理 Supplement　32　(3)　233-234　2012/09/13

ISSN： 1345-5362
Perfusion MRIによる骨格筋の微小循環測定の試み

磯辺智範, 岡本嘉一, 平野雄二, 森慎太郎, 佐藤英介, 森祐太朗, 森祐太郎, 安藤浩樹

医学物理 Supplement　32　(3)　235-236　2012/09/13

ISSN： 1345-5362
骨格筋proton MRSにおける計測成功率に関する検討

磯辺智範, 岡本嘉一, 平野雄二, 森慎太郎, 佐藤英介, 鈴木浩明

日本放射線技術学会雑誌　67　(9)　1037-1037　2011/09/20
Publisher: (公社)日本放射線技術学会
ISSN： 0369-4305
先天性股関節脱臼における関節唇の3DMRIによる評価

阿部亮子, 鎌田浩史, 三島初, 西野衆文, 中村木綿子, 落合直之, 岡本嘉一

日本小児整形外科学会雑誌　20　(1)　49-53　2011/03
Publisher: (一社)日本小児整形外科学会
ISSN： 0917-6950
骨格筋FA値のstandard map

磯辺智範, 只野喜一, 平野雄二, 森慎太郎, 佐藤英介, 岡本嘉一

日本放射線技術学会総会学術大会予稿集　67th　120-120　2011/02/25
Publisher: (公社)日本放射線技術学会
ISSN： 1884-7846
Comparison of tumor regression rate of uterine cervical squamous cell carcinoma during external beam and intracavitary radiotherapy Peer-reviewed

Ohara, Kiyoshi, Tanaka, Yumiko Oishi, Oki, Akinori, Okamoto, Yoshikazu, Satoh, Toyomi, Matsumoto, Koji, Yoshikawa, Hiroyuki

RADIATION MEDICINE　26　(9)　526-532　2008/11
Publisher: SPRINGER
DOI： 10.1007/s11604-008-0268-1 　

ISSN： 1862-5274
子宮頸部--良悪性鑑別とがんの組織型(MRI) (産婦人科新画像診断--外来・病棟で役立つ画像判読のポイント) -- (婦人科腫瘍)

岡本嘉一, 田中優美子, 南学

産科と婦人科　74　245-250　2007
Publisher: 診断と治療社
ISSN： 0386-9792

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Books and Other Publications 13

インナービジョン

岡本,嘉一

2019/09
Whole-body vibration for patients with nonalcoholic fatty liver disease: a 6-month prospective study

Oh, Sechang, Oshida, Natsumi, Someya, Noriko, Maruyama, Tsuyoshi, Isobe, Tomonori, Okamoto, Yoshikazu, Kim, Taeho, Kim, Bokun, Shoda, Junichi

WILEY　2019/05

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Physical exercise has demonstrated benefits for managing nonalcoholic fatty liver disease (NAFLD). However, in daily life maintaining exercise without help may be difficult. A whole-body vibration device (WBV) has been recently introduced as an exercise modality that may be suitable for patients who have difficulty engaging in exercise. We tested WBV in patients with NAFLD and estimated its effectiveness. We studied the effects of a 6-month WBV program on hepatic steatosis and its underlying pathophysiology in 25 patients with NAFLD. Seventeen patients with NAFLD were designated as a control group. After WBV exercise, body weight in the study group decreased by only 2.5% compared with the control group. However, we found significant increases in muscle area (+2.6%) and strength (+20.5%) and decreases in fat mass (-6.8%). The hepatic (-9.9%) and visceral (-6.2%) fat content also significantly decreased (P < 0.05). There was substantial lowering of hepatic stiffness (-15.7%), along with improvements in the levels of inflammatory markers; tumor necrosis factor alpha (-50.9%), adiponectin (+12.0%), ferritin (-33.2%), and high-sensitivity C-reactive protein (-43.0%) (P < 0.05). Th
Whole-body vibration for patients with nonalcoholic fatty liver disease: a 6-month prospective study

Oh, Sechang, Oshida, Natsumi, Someya, Noriko, Maruyama, Tsuyoshi, Isobe, Tomonori, Okamoto, Yoshikazu, Kim, Taeho, Kim, Bokun, Shoda, Junichi

WILEY　2019/05

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Physical exercise has demonstrated benefits for managing nonalcoholic fatty liver disease (NAFLD). However, in daily life maintaining exercise without help may be difficult. A whole-body vibration device (WBV) has been recently introduced as an exercise modality that may be suitable for patients who have difficulty engaging in exercise. We tested WBV in patients with NAFLD and estimated its effectiveness. We studied the effects of a 6-month WBV program on hepatic steatosis and its underlying pathophysiology in 25 patients with NAFLD. Seventeen patients with NAFLD were designated as a control group. After WBV exercise, body weight in the study group decreased by only 2.5% compared with the control group. However, we found significant increases in muscle area (+2.6%) and strength (+20.5%) and decreases in fat mass (-6.8%). The hepatic (-9.9%) and visceral (-6.2%) fat content also significantly decreased (P < 0.05). There was substantial lowering of hepatic stiffness (-15.7%), along with improvements in the levels of inflammatory markers; tumor necrosis factor alpha (-50.9%), adiponectin (+12.0%), ferritin (-33.2%), and high-sensitivity C-reactive protein (-43.0%) (P < 0.05). Th
臨床画像

岡本,嘉一

2018/05
画像診断

岡本, 嘉一, 吉沢知宏

2017/12

ISBN: 9784780900972
臨床画像32(12)

石黒, 聡尚, 小熊, 栄二, 細川, 崇洋, 岡本, 嘉一, 南, 学

メジカルビュー社　2017/11
Imaging of the Upper Extremity: Elbow, Wrist and Hand

岡本,嘉一

2017/04

ISBN: 9784895928700
MRIルーチンクリニカルブック増刊

岡本, 嘉一

2014/12
骨軟部画像診断スタンダード

岡本,嘉一

2014/06
新骨軟部画像診断の勘ドコロ

岡本,嘉一

2014/05
整形・災害外科

岡本,嘉一

2011/04
INNERVISION

岡本,嘉一

2011/03
子宮頚部腺癌・悪性腺腫と嚢胞性頚部良性病変とのMRIによる鑑別

Okamoto,Yoshikazu

2007/10

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Presentations 78

長距離走者で遠位の除脂肪重量が下肢慣性モーメントと強く関係する

枝川, 岳史, 藤森, 俊秀, 橋本, 昇悟, 岡本, 嘉一, 中島, 崇仁, 佐渡, 夏紀

第36回日本トレーニング科学会
Pectoralis major and deltoid muscularity in shot putters: Reversal of whether cross-sectional area or volume is related to performance

Hashimoto, S, T., Fujimori, Edagawa T, K, Ohyama-Byun, Y., Okamoto, T., Nakajima, N., Sado

29th Congress of International Society of Biomechanics / Japanese Society of Biomechanics
Unique mass distribution in the lower limbs of distance runners and its effect on moment of inertia

Edagawa T, Fujimori T, Hashimoto, S, Okamoto, Y, T., Nakajima, Sado, N

29th Congress of International Society of Biomechanics / Japanese Society of Biomechanics
Hip and lumbosacral joint centre locations in Asian population: biases by existing regressions and development of new methods

Sado, N, T., Edagawa, T., Fujimori, S., Hashimoto, Y., Okamoto, T., Nakajima

The 41st Annual Conference of the International Society of Biomechanics in Sports
Three-dimensional developmental aspects of the pectoralis major and deltoid muscles in shot putters

Hashimoto, S, Fujimori, T, Edagawa, T, K, Ohyama-Byun, Okamoto, Y, Nakajima, T, Sado, N

The 28th Annual Congress of the European College of Sport Science
Lower-limb moment of inertia in the anatomical position does not explain the inter-individual variation in O2 cost in trained endurance runners

Edagawa, T, Fujimori, T, Akutsu, K, Hashimoto, S, Fujii, N, Okamoto, Y, Nakajima, T, Sado, N

The 28th Annual Congress of the European College of Sport Science
Muscularity of the upper limb and upper trunk in shot putters.

橋本, 昇悟, 藤森, 俊秀, 大山卞, 圭悟, 岡本, 嘉一, 中島, 崇仁, 佐渡夏紀

第35回日本トレーニング科学会大会　2022/12/03
Application of Mobile MRI to Upper Extremity Examination for Wheelchair Users

Naoto, Momiyama, Yoshikazu, Okamoto, Yukiyo, Shimizu, 寺田, 康彦

第50回日本磁気共鳴医学会大会　2022/09/09
Hip and lumbosacral joint centre locations in Asian population: biases by existing regressions and development of new methods

Sado, N, T., Edagawa, T., Fujimori, S., Hashimoto, Y., Okamoto, T., Nakajima

The 41st Annual Conference of the International Society of Biomechanics in Sports
Usability assessment of temporal subtraction computed tomography images using deep learning to detect vertebral bone metastases

星合, 壮大, 花岡昇平, 増本智彦, 野村行弘, 森健作, 岡本嘉一, 齋田司, 石黒聡尚, 酒井正史, 中島崇仁

第80回日本医学放射線学会総会　2021/04/15
Development and screening examination of a car-mounted portable MRI for wrist

Tomoki, Miyasaka, Michiru, Kajiwara, Akito, Kawasaki, Yoshikazu, Okamoto, 寺田, 康彦

第48回日本磁気共鳴医学会大会（WEB開催）　2020/09/11
ポータブルMRIを用いた手首診断

宮坂, 知樹, 梶原, 成生, 川崎, 亮人, 岡本, 嘉一, 寺田, 康彦

第24回NMRマイクロイメージング研究会　2020/08/28
Clinical feasibility of mobile medical screening for wrist injuries in tennis players using a small car-mounted MRI International-presentation

Miyasaka, Tomoki, Kajiwara, Michiru, Kawasaki, Akito, Okamoto, Yoshikazu, Terada, Yasuhiko

2020 ISMRM & SMRT Virtual Conference & Exhibition　2020/08/08
教育講演肘関節 - 基礎から最新知見まで -

岡本,嘉一

骨軟部放射線セミナー
時短練習と試合数の大幅減が生んだ選手たちへの計り知れない好影響

岡本,嘉一

西武ライオンズ埼玉ベースボールサミット
教育講演 MRI を用いた骨格筋微小解剖の解析

岡本,嘉一

ARIHHP コーチングカフェ
教育講演上肢関節の画像診断～MRI画像を中心に～

岡本,嘉一

茨城県南技師基礎講習会
教育講演骨軟部 2 上肢

岡本,嘉一

第47回日本磁気共鳴医学会
Field examination of baseball elbow using a car-mounted portable MRI

梶原, 成生, 中込, 真優, 岡本, 嘉一, 寺田, 康彦

第47回日本磁気共鳴医学会大会　2019/09/20
教育講演肘関節 - 基礎から最新知見まで -

岡本,嘉一

第30回骨軟部放射線セミナー
ポータブル MRI の野球場での撮像試験

梶原, 成生, 宮坂, 知樹, 岡本, 嘉一, 寺田, 康彦

第23回NMRマイクロイメージング研究会　2019/08/08
Image denoising with deep transfer learning for screening baseball elbow injuries using portable scanners International-presentation

Nakagomi, Mayu, Hoshiai, Sodai, Okamoto, Yoshikazu, Terada, Yasuhiko

International Society for Magnetic Resonance in Medicine 2019　2019/05/11

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Portable MRI scanners have the advantages of maximizing clinical availability in remote environments. We have recently developed a portable, elbow scanner installed in a standard-size car. This system allows us to detect early symptoms of baseball elbow in remote places, but it often suffers from the low signal-to-noise ratio in noisy, outdoor environments. Here we proposed a deep-learning based approach, a denoising convolutional neural network with transfer learning, for denoising images of the potable scanner. We verified that the proposed denoising technique improved the quality of noisy images and increased the clinical feasibility of the portable scanner.
脊椎骨転移の検出における経時差分CT画像の有用性評価

星合, 壮大, 増本智彦, 花岡, 昇平, 野村, 行弘, 森健作, 岡本, 嘉一, 齋田司, 原, 唯史, 古西, 崇寛, 南, 学

第78回医学放射線学会総会　2019/04/11
クラウドファンディングを用いたMRI 野球肘検診車制作と少年スポーツ改革

岡本,嘉一

山梨MRI技術研究会
Characteristics of MRI findings of upper extremities of Wheelchair Users

岡本,嘉一

JSMR 30th annual meeting　2019/01/24
非アルコール性脂肪性肝疾患（NAFLD）における骨格筋異常−超音波を用いた解析と評価

磯辺, 智範, 押田, 夏海, 志田, 隆史, 岡本, 嘉一, 上牧, 隆, 正田, 純一

第42回日本肝臓学会東部会　2018/12/07
次世代型少年野球チームの取り組みと少年野球改革

岡本,嘉一

第6回日本野球科学研究会
非アルコール性脂肪性肝疾患（NAFLD）における骨格筋異常−超音波を用いた解析と評価

磯辺, 智範, 押田, 夏海, 志田, 隆史, 岡本, 嘉一, 上牧, 隆, 正田, 純一

日本超音波医学会第30回関東甲信越地方会学術集会　2018/10/27
Deep convolutional neural network for denoising images of low-field scanners

中込, 真優, 田辺, 亮勝, 星合, 壮大, 岡本, 嘉一, 寺田, 康彦

第46回日本磁気共鳴医学会大会　2018/09/07
Development of portable MRI for detection of baseball elbow (3)

中込, 真優, 田辺, 亮勝, 巨瀬, 勝美, 岡本, 嘉一, 星合, 壮大, 寺田, 康彦

第46回日本磁気共鳴医学会大会　2018/09/07
永久磁石 MRI における深層学習を用いたノイズ除去の検討

寺田, 康彦, 中込, 真優, 岡本, 嘉一

第22回NMRマイクロイメージング研究会　2018/08/20
手・肘関節の MRI～局所解剖と病態の理解～

岡本,嘉一

第29回骨軟部放射線診断セミナー
Development of a small-car mountable MRI system for human extremities using a 0.2 T permanent magnet. International-presentation

Tanabe, Katsumasa, Nakagomi, Mayu, Kose, Katsumi, Okamoto, Yoshikazu, Hoshiai, Sodai, Terada, Yasuhiko

Joint Annual Meeting ISMRM-ESMRMB 2018　2018/06/16
Evaluation of Temporal Subtraction CT for detection of vertebral bone metastases

星合, 壮大, 増本, 智彦, 花岡, 昇平, 野村, 行弘, 岡本, 嘉一, 原, 唯史, 菊地, 俊介, 南, 学

第77回医学放射線学会総会　2018/04/12
肘関節

岡本,嘉一

日本医学放射線学会関東地方会セミナー
Development of portable MRI for early detection of baseball elbow. International-presentation

Tanabe, Katsumasa, Kose, Katsumi, Terada, Yasuhiko, Okamoto, Yoshikazu

14th International Conference on Magnetic Resonance Microscopy　2017/08/13
Adaptation of Medial Epicondyle in Adolescent Baseball Player Observed on MRI. International-presentation

Okamoto, Yoshikazu, Minami, Manabu

The103th Annual meeting of Radiological Society of North America　2017/11
医療画像を使った少年野球選手の野球肘検診 Invited

岡本,嘉一

第36回福岡大学烏帽子会（福岡）　2017/07
関節のMRI診断 Invited

岡本,嘉一

第24回茨城MRI情報交換会　2017/06
Medial epicondyle adaptation as a baseball player in adolescence observed on MRI.

Yoshikazu, Okamoto, Manabu, Minami

International society for Magnetic Resonance in Medicine　2017/04
The Interpretation of ‘Asymptomatic MCL Injury of the Elbow in Youth Baseball Players on MRI’. International-presentation

Okamoto,Yoshikazu

Radiological Society for North America 102th annual meeting　2016/11
上肢のスポーツ障害

岡本,嘉一

第27回日本骨軟部放射線診断セミナー　2016/08
整形外科領域のMRI最前線～関節外傷の知見を絡めて～ Invited

岡本,嘉一

JCOG 関東支部会　2016/08
MRI を用いた骨格筋微小解剖の解析 Invited

岡本, 嘉一

第19回MR実践講座「骨軟部領域MRI update」　2015/12
Preliminary results of early detection of baseball elbow in Japanese elementary school boys and girls using low field magnetic resonance imaging specialized for small.

Okamoto, Yoshikazu, Minami, Manabu

42nd annual meeting International Skeletal Society　2015/09
Is intramyocellular lipid a diffusion-restricting factor in skeletal muscle cells?

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2015/06
肘の画像診断 Invited

岡本, 嘉一

第74回日本医学放射線学会総会　2015/04
野球肘のMRI による検診の試み.、国立スポーツ科学センター（東京）11月、2014

岡本, 嘉一, 南学

第25回日本臨床スポーツ医学会学術集会　2014/11
筋肉トレーニングによる骨格筋細胞内拡散変化の追跡

岡本, 嘉一, 磯辺智範

第42回日本磁気共鳴医学会大会（京都）　2014/09

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岡本嘉一、磯辺智範、平野雄二、正田純一、南学：
MRI 拡散強調画像を極める。 Invited

岡本, 嘉一

第25回骨軟部放射線セミナー　2014/08
MRIによる骨格筋の新解析手法 Invited

岡本, 嘉一

第25回日本骨軟部放射線研究会　2014/01
Skeletal muscle MRI– Great potential for future clinical application International-presentation

Okamoto, Yoshikazu, Minami, Manabu

Radiological Society for North America 99th annual meeting　2013/12
1H-MRS (Spectroscopy) による骨格筋脂肪と肝臓脂肪の同時測定の試み.

岡本, 嘉一, 南学

第24回日本臨床スポーツ医学会学術集会　2013/10
上肢の外傷：単純写真～整形外科医が必要とする情報～ Invited

岡本,嘉一

骨軟部放射線セミナー　2013/08
Changes in diffusion tensor imaging (DTI) eigenvalues of skeletal muscle due to hybrid exercise training International-presentation

Yoshikazu, Okamoto, Minami, Manabu

International Society for Magnetic Resonance in Medicine 21th annual meeting　2013/04
Different kinetics of post-exercise perfusion fraction by diffusion-weighted imaging between athletes and non-athletes International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2013/04
Does skeletal muscle contain fast and slow diffusion components in high b-value diffusion weighted imaging (DWI) International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2013/04
Slow training effect on intracellular lipid in skeletal muscle International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2013/04
Imaging of the Elbow Joint – minimal essence – . Invited

岡本, 嘉一

第72回日本医学放射線学会総会　2013/04
骨格筋のMRI-人体骨格筋の拡散テンソル画像を用いた研究-

岡本,嘉一

Body diffusion 研究会　2013/02
New evaluation method for human skeletal muscle at the microscopic level using MRI. International-presentation

Okamoto, Yoshikazu, Minami, Manabu

Radiological Society for North America　2012/12
スポーツ外傷における軟骨損傷の評価. Invited

岡本,嘉一

第48回日本医学放射線学会秋季臨床大会　2012/09
Diffusion Property Differences of the Lower Leg Musculature between Athletes and Non-Athletes using 1.5T MRI. ISMRM 20th annual meeting International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2012/05
The measurement and interpretation of intravoxel incoherent motion (IVIM) of skeletal muscle in vivo: preliminary results. International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2012/05
MRI assessment of Slow training effect on focal fat metabolism in skeletal muscle International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2012/05
The correlation between pennation angle and the image quality of skeletal muscle fiber tractography using the deterministic diffusion tensor imaging International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2012/05
スロートレーニングが局所の骨格筋脂肪代謝に与える影響の検討．

岡本,嘉一

第22回日本臨床スポーツ医学会学術集会　2011/11
Multi-b diffusion を用いた骨格筋細胞内腔と外腔の比率（fraction）測定の試み.

岡本, 嘉一, 南学

第39回日本磁気共鳴医学会大会　2011/09
3T 1H-MR spectroscopy （1H-MRS）と LCModel による骨格筋 IMCL と EMCL 計測成功率の計測対象による差異の検討.

岡本, 嘉一, 南学

第39回日本磁気共鳴医学会大会　2011/09
日常診療に役立つ関節の読み方、肘関節. Invited

岡本,嘉一

放射線科専門医会・医会ミッドサマーセミナー　2011/07
Elucidation for improvement of visualization in the skeletal muscle tractography using probabilistic diffusion tractography – Preliminary result – International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2011/05
3T MRIを用いた健常ボランティアの骨格筋細胞内脂肪（IMCL）と身体データの相関性の観察と検討.

岡本, 嘉一, 南学

第70会日本医学放射線学会総会　2011/05
Evaluation of Activity, Making Diagnosis and Prediction of Future Bone Destruction by Using Low Field Compact Magnetic Resonance Imaging Machine in Patients with Rheumatoid Arthritis

Sugihara, Makoto, Suzuki, Takeshi, Okamoto, Yoshikazu, Horikoshi, Masanobu, Yokosawa, Masahiro, Hagiwara, Shinya, Hirota, Tomoya, Takano, Yohei, Umeda, Naoto, Kondo, Yuya, Tsuboi, Hiroto, Ogishima, Hiroshi, Hayashi, Taichi, Chino, Yusuke, Goto, Daisuke, Matsumoto, Isao, Sumida, Takayuki

75th Annual Scientific Meeting of the American-College-of-Rheumatology/46th Annual Scientific Meeting of the Association-of-Rheumatology-Health-Professionals　2011
Evaluation of the Change of Intramyocellular Lipid Metabolism due to Long-term Skeletal Muscle Training of the Calf by 3 T H-MR Spectroscopy International-presentation

Okamoto, Yoshikazu, Minami, Manabu

Radiological Society for North America　2010/12
Comparison of Diffusion Property Differences of the Calf Muscles between Athletes and Non-athletes. International-presentation

Okamoto,Yoshikazu

International Society for Magnetic Resonance in Medicine　2010/05
Change of MR diffusion property during Active Muscle Contraction in the Calf. International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2010/05
Comparison of Diffusion Property Differences of the Calf Muscles between Athletes and Non-athletes International-presentation

Okamoto, Yoshikazu, Minami, Manabu

Radiological Society for North America　2009/12
Gender-specific differences in MR fiber tractography of skeletal muscles International-presentation

Okamoto, Yoshikazu, Minami, Manabu

International Society for Magnetic Resonance in Medicine　2009/04

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Research Projects 15

未来を読み解く現場診断学：可搬型MRIと動作解析による障害予測

岡本嘉一

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(B)

Institution: 東北大学

2026/04/01 - 2029/03/31
内耳およびその周辺構造の3Dモデル教材の開発とその教育効果の検討

石黒聡尚, 岡本嘉一

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(C)

Institution: 筑波大学

2022/04/01 - 2027/03/31
Motion analysis of upper limb loading of wheelchair users and prevention of disability using moment of inertia

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: University of Tsukuba

2022/04/01 - 2025/03/31
Elucidating the Pathogenesis of Baseball Elbow from Next-generation Elbow Examination: Fusion of Echo Examination and Vehicle-mounted Compact MRI

Takeshi Ogawa

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

2019/04/01 - 2022/03/31

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There were two main objectives of this study. One was to accumulate and analyze big data by integrating "echo elbow examination" and "MRI examination vehicle," and the other was to elucidate the pathophysiology of medial elbow disorders from the analysis data of "high-resolution MRI" and "echo elbow examination. The diagnostic accuracy of osteochondritis dissecans by vehicle-borne MRI was good, although the number of cases was small. In addition, we were able to evaluate the pathophysiology of early baseball elbow in detail using high-resolution MRI.
A new hybrid treatment with acceleration training and hydrogen for non-alcoholic fatty liver disease

Isobe Tomonori

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: University of Tsukuba

2018/04/01 - 2021/03/31

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The purpose of this study was to clarify that treatment by acceleration training and hydrogen water intake effectively improves the metabolism of NAFLD (nonalcoholic fatty liver disease). We aimed to (1) evaluate the effect of hydrogen water on exercise endurance capacity and (2) devise a new acceleration training program. As a result, drinking hydrogen water for four weeks or more greatly reduced the body fat percentage and significantly improved the exercise endurance capacity. In addition, the practice of the new acceleration training program devised with whole body vibration greatly improved the degree of fatigue and subjective symptoms of the obese participants with NAFLD.
Pitching motion of elbow injuries in young baseball players by 3D motion analysis and medical examination of elbow injuries

KANAHORI Tetsuya, OKAMOTO Yoshikazu, KAWAMURA Takashi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

Institution: University of Tsukuba

2016/04/01 - 2018/03/31

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The purpose of this study was to reveal coaching method for preventing elbow injuries by considering the result of pitching motion analysis and medical examination of elbow injuries. We analyzed MRI scan and 3D-motion analysis of pitching motions of 60 boys and girls who play baseball. The result showed that, the abduction angle of the thrower’s shoulder joint and the abduction angle of the pivot foot hip joint when the step foot lands on the ground were bigger in the positive persons’ group than the negative persons’ group. Furthermore, the extension angle of pivot foot hip joint and the flexion angle of the thrower’s elbow joint at a time of ball release were bigger in the positive person’s group. Therefore we suggested that baseball coaches should not focus only on increase of the pitch velocity, but on narrowing the stride width that keeps the upper body from leaning forward when the thrower’s elbow rises to release a ball and the step foot lands on the ground.
Influence of exercise type on human brown fat: Assessment by MRI

SATOH Makoto, OKAMOTO Yoshikazu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: University of Tsukuba

2016/04/01 - 2018/03/31

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Brown adipose tissue (BAT) is known to increase from cold-exposure, but its effect on exercise stimulation has not been clarified. The present study compared the athletes that train on land and under water, and sedentary controls to elucidate how the differences in chronic exercise types change the BAT quantity from MRI analysis. The results showed that the BAT amount was significantly higher among swimmers than the athletes that train on land or the control group. Furthermore, BAT amount was greater during winter than in summer for all groups, but the amount of change was smaller among swimmers. This suggested that continuous swimming exercise stimulation may be an effective means to increase and maintain the BAT.
The skeletal muscle conditioning for sports athletes by using multilateral evaluation system of magnetic resonance imaging

Okamoto Yoshikazu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: University of Tsukuba

2014/04/01 - 2018/03/31

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The main result of our study was to evaluate the microanatomy of the skeletal muscle using diffusion tensor imaging (DTI). We clarified the morphology of the skeletal muscle cell by using eigenvectors calculated by DTI. And also we clarified the existance of another diffusion restricting factors except for the membrane of the skeletal muscle cell. Moreover, we could succesfully generate the fiber tractography of the skeletal muscle by also using DTI. We also clarified the factors of failure of generating fiber tractography. As for the lipid metaboolism of the skeletal muscle measured by MR spectroscopy, we clarified several factors including diabetis and subject's age could also affect the successful measurement of lipid metabolism of the skeletal muscle.
Establishment of non-invasive pathology evaluation for nonalcoholic fatty liver disease using functional imaging

ISOBE Tomonori

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: University of Tsukuba

2014/04/01 - 2017/03/31

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Nonalcoholic fatty liver disease (NAFLD) is divided into two types: simple fatty liver and Non-alcoholic steatohepatitis. Pathology evaluation for NAFLD has been mainly performed by liver biopsy, blood test and form information of diagnostic imaging. In this study, an objective diagnostic index was established by functional imaging information from a point of view of a relationship to pathology. Moreover, a new method was proposed for the evaluation using functional information of the liver and the skeletal muscle which control glycolipid metabolism. This method is our original and not has been presented in previous studies.
Establishment of the method to detect endoleaks after stentgrafting using unenhanced MRI

Mori Kensaku, SAIDA Tsukasa, MINAMI Manabu, SATO Fujio, NASU Katsuhiro, OKAMOTO Yoshikazu, SHIIGAI Masanari, YABE Hitoshi, SHINDO Masayuki, YAMADA Kouji, TOKI Taketo

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: University of Tsukuba

2012/04/01 - 2016/03/31

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The detection of endoleaks is important to prevent late aortic aneurysm rupture after endovascular aneurysm repair (EVAR). For this purpose, contrast-enhanced computed tomography (CE-CT) is most widely used; however we often encounter the cases, where CE-CTis contraindicated due to renal dysfunction. To evaluate the feasibility of unenhanced MRI using motion-sensitized driven equilibrium (MSDE) prepared balanced turbo field echo (BTFE) sequences for the detection of endoleaks after EVAR, we performed a phantom study using a pulsatile flow generator and a clinical study with CE-CT as the reference standard. As a result, the MSDE prepared BTFE sequences were clinically feasible and provided high diagnostic performance.
肝-骨格筋臓器連関に着目したマルチモダリティによる生活習慣病の包括的病態評価

江口清, 磯辺智範, 正田純一, 岡本嘉一

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 挑戦的萌芽研究

Institution: 筑波大学

2013/04/01 - 2015/03/31

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生活習慣病の発生には、糖脂質代謝の異常が深く関与している。これら糖脂質代謝は、主に肝臓と骨格筋とが密接に関連しながらコントロールされていることが知られている。しかし、実際にどのような形で関連しているかという詳細な病態生理に関しては、依然不明な点が多い。これらの解明には、「肝臓のみ」あるいは「骨格筋のみ」といった縦断的な研究手法ではなく、「肝臓および骨格筋の機能を同時に評価する研究手法」が必要である。本研究の目的は、複数の生体機能情報をマルチモダリティ(MRI, 超音波)により同時期に測定・解析し、血液や身体データといった血液生化学データと比較することによって、生体内の代謝機能を肝-骨格筋臓器連関という観点で捉え、生活習慣病における病態生理を解明するための正常データのライブラリを構築することである。肝臓および骨格筋において、安定的かつ正確にMRIデータ「MR spectroscopy : 骨格筋の細胞内脂肪(IMCL)・細胞外脂肪(EMCL), 肝臓内脂肪)/MR perfusion(骨格筋の微小循環), MR diffusion(骨格筋の拡散固有値)」と超音波データ「Controlled Attenuation Parameter (CAP) : 肝臓内脂肪量/Fibroscan : 肝臓の硬度)を取得するための撮像パラメータの最適化に成功した。さらに、本研究では、最適化した撮像パラメータにより、健常ボランティアの「MRI、超音波、血液および体組成(肝機能, 筋酵素, 血糖値, インスリン値, 脂質, 遊離脂肪酸, 脂肪酸組成, 身長, 体重)データ」を取得し、正常データライブラリの構築に成功した。このライブラリは、今後、食事療法と運動療法を要する肥満者および慢性肝疾患患者等の疾患群と比較する際の基礎データとなるため、本研究の臨床的意義は大きい。
Improvement of metabolic and exercise function of skeletal muscles through activation of transcription factor, and prevention of obesity-related liver disease

SHODA Junichi, YANAGAWA Toru, ISHII Tetsuro, UTSUNOMIYA Hirohuto, GOTO Naohiro, WARABI Eiji, OKAMOTO Yoshikazu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: University of Tsukuba

2011/04/01 - 2014/03/31

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Each mouse group was subjected to the maximum exercise tolerance test. The results showed that the running distance was significantly shorter in Nrf2KO mice than in wild-type mice. The distance was observed to become longer in the wild-type mice with Nrf2 activation by sulforaphan, a potent Nrf2 activator. The ameliorating effect of exercise on hepatic steatosis of mice fed high sucrose and fat diet was observed in the wild-type mice but not in the Nrf2KO mice. Therefore, we developed cultured myocytes from mouse muscle tissues and investigated the effect of exercise training on myokine production and secretion in the cells. Upon electrical stimulation, Nrf2 was observed to be activated in the myocytes and the production of IL-6, a myokine was markedly increased in the cells. It is likely that Nrf2 expression in myocytes is an important factor influential on exercised-induced myokine production and secretion in the muscles.
Activation of transcription factor by functional food constituents inhibits the onset and progression of obesity-related liver diseases through attenuating the enhanced innate immunity levels.

TAKAHASHI Hiroshi, SHODA Junichi, YANAGAWA Toru, UTSUNOMIYA Hirotoshi, OKAMOTO Yoshikazu, ISHII Tetshurou

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: University of Tsukuba

2010 - 2012

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In Keap1-kd mice (with Nrf2 overexpression) fed an MCD diet, steatohepatitis did not develop over the observation periods. However, in Nrf2-null mice fed the diet, the pathological state of the steatohepatitis was aggravated. Iron accumulation was greater in the livers of the Nrf2-null mice compared to those of the WT mice, and it was not observed in Keap1-kd mice. Further, the iron release from the isolated hepatocyte of Nrf2-null mice was significantly decreased. Sulforaphane, an activator of Nrf2, suppressed the pathological states and oxidative stress in the livers.Nrf2 has protective roles against nutritional steatohepatitis through inhibition of hepatic iron accumulation and counteraction against oxidative stress-induced liver injury.
Inhibitory effects of exercise on progression of obesity-related liver diseases and development of glyco-biomarkers to scale the pathophysiology of the liver diseases

SHODA Junichi, AJISAKA Ryuichi, FUKUDA Kuniaki, OKAMOTO Yoshikazu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: University of Tsukuba

2010 - 2011

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In management of obesity-related liver diseases, that is, non-alcoholic fatty liver diseases, it is important to increase a utilization of glucose in the skeletal muscles and thereby to improve the insulin-resistance. Therefore, in subjects with non-alcoholic fatty liver diseases, it is also important to maintain the volume of skeletal muscles by appropriate exercise. In the assessment of effects of exercise on liver pathophysiology of non-alcoholic fatty liver diseases, we need to explore novel biomarkers that can reflect the status of liver pathophysiology in terms of steatosis, inflammation, and fibrosis, and to develop a non-invasive measurement system of these biomarkers. In this research project, using the serum samples of middle-aged obese men who joined a weight-losing course, we explored novel biomarkers that can scale the improvement of liver pathophysiology induced by exercise. We measured an enzyme activity of N-acetylglucosaminyltransferase V (GnT-V) in the serum samples as a glyco-biomaker. Exercise increased the energy consumption, maintained the lean body mass, and decreased the serum levels of ferritin and TBARS, an oxidative stress marker, in comparison with diet restriction. Taken together, it is likely that serum levels of ferritin and TBARS are useful biomarkers to scale the effects of exercise on liver pathophysiology in obese men. Exploration of novel glycol-biomarkers is being performed.
Clinical application of diffusion tensor imaging for the skeletal muscle

OKAMOTO Yoshikazu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

Institution: University of Tsukuba

2009 - 2011

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It is very rare to perform skeletal muscle MRI in the daily practice. However, we applied diffusion tensor imaging (DTI), which was new imaging technique, to the skeletal muscle, and we could make it possible to depict skeletal muscle fiber. In addition, we could grasp the microanatomy of the skeletal muscle by DTI. Moreover, we could also realize to measure the lipid metabolism at the skeletal muscle using MR spectroscopy. We have presented these several research results in the conference held in Japan, or the other international meetings. And also we presented it by three research papers during research period.

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Field baseball elbow screening of youth baseball players using portable MRI
Elbow screening for young baseball players using dedicated MRI
肘を故障しない少年野球チームの運営