受賞区分：学会誌・学術雑誌による顕彰 

受賞区分：学会誌・学術雑誌による顕彰 

受賞区分：学会誌・学術雑誌による顕彰 

受賞区分：国内学会・会議・シンポジウム等の賞 

受賞区分：国内外の国際的学術賞  受賞国：日本国

受賞区分：国際学会・会議・シンポジウム等の賞  受賞国：オーストリア共和国

受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

受賞国：日本国

受賞区分：国内学会・会議・シンポジウム等の賞 

受賞区分：国内学会・会議・シンポジウム等の賞 

受賞区分：国内外の国際的学術賞  受賞国：アメリカ合衆国

受賞国：日本国

受賞国：日本国

受賞国：日本国

久保田誠司、伊藤善之、副松由加、野本由人、村尾豪之、山川耕二、 石原俊一、平澤直樹、浅野晶子、長縄慎二　　　　 I期声門癌に対する1回2.25Gyを用いた寡分割照射例の多施設調査

受賞国：日本国

受賞国：シンガポール共和国

受賞国：グレートブリテン・北アイルランド連合王国(英国)

受賞国：日本国

Objective diagnosis of Meniere´s disease by clinically applicable method:How to do it　メニエール病のＭＲＩによる簡便な客観診断法；How to do it

受賞区分：国際学会・会議・シンポジウム等の賞 

受賞国：日本国

受賞国：日本国

鼓室内Gd注入によるメニエール病患者における内リンパ水腫をMRIを用いてはじめて画像化した。

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/jog.15998

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.mp.2023-0168

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00016489.2024.2363462

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0300325

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00016489.2024.2329783

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-023-01498-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/lio2.1210

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.mp.2023-0016

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1097/MAO.0000000000003981

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s12194-023-00745-y

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11547-023-01691

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41467-023-40507-3

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18999/nagjms.85.3.504

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.mp.2021-0162

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-023-01408-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18999/nagjms.85.2.375

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fneur.2023.1193104

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.anl.2022.01.0040385-8146

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00016489.2023.2182450

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/lio2.998

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.5230/jgc.2022.22.e30

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10047-022-01312-9

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s12149-022-01754-4

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18999/nagjms.84.3.497

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fsurg.2022.874971

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fsurg.2022.913741

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/database/baz085

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ijrobp.2019.06.1809

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ijrobp.2019.06.1708

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-018-0770-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00415-018-8923-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.wneu.2018.05.181

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00280-018-3554-3

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1177/2058460118769687

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.clinph.2017.11.018

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fnhum.2018.00148

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ejmp.2017.10.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/jrr/rrx051

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/acm2.12116

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00330-016-4654-2

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/jjco/hyx021

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.ci.2016-0114

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-017-0617-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00016489.2016.1232862

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18999/nagjms.79.2.211

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1148/rg.2017160061

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00016489.2016.1217042

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-016-0600-0

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0170309

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-024-01668-3

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その他リンク： https://link.springer.com/article/10.1007/s11604-024-01668-3/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s12149-024-01981-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11547-024-01861-4

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その他リンク： https://link.springer.com/article/10.1007/s11547-024-01861-4/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.rev.2023-0175

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-024-01552-0

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/nbm.5030

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.diii.2024.06.002

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-024-01536-0

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その他リンク： https://link.springer.com/article/10.1007/s11604-024-01536-0/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1177/0271678X241245492

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その他リンク： https://journals.sagepub.com/doi/full-xml/10.1177/0271678X241245492

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.mp.2024-0011

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Portal vein thrombosis (PVT) is thought to arise from stagnant blood flow, yet conclusive evidence is lacking. Relative residence time (RRT) assessed using 4D Flow MRI may offer insight into portal flow stagnation. PURPOSE: To explore the relationship between RRT values and the presence of PVT in cirrhotic participants. STUDY TYPE: Prospective. POPULATION: Forty-eight participants with liver cirrhosis (27 males, median age 67 years [IQR: 57-73]) and 20 healthy control participants (12 males, median age 45 years [IQR: 40-54]). FIELD STRENGTH/SEQUENCE: 3 T/4D Flow MRI. ASSESSMENT: Laboratory (liver and kidney function test results and platelet count) and clinical data (presence of tumors and other imaging findings), and portal hemodynamics derived from 4D Flow MRI (spatiotemporally averaged RRT [RRT-mean], flow velocity, and flow rate) were analyzed. STATISTICAL TESTS: We used multivariable logistic regression, adjusted by selected covariates through the Lasso method, to explore whether RRT-mean is an independent risk factor for PVT. The area under the ROC curve (AUC) was also calculated to assess the model's discriminative ability. P < 0.05 indicated statistical significance. RESULTS: The liver cirrhosis group consisted of 16 participants with PVT and 32 without PVT. Higher RRT-mean values (odds ratio [OR] 11.4 [95% CI: 2.19, 118]) and lower platelet count (OR 0.98 per 1000 μL [95% CI: 0.96, 0.99]) were independent risk factors for PVT. The incorporation of RRT-mean (AUC, 0.77) alongside platelet count (AUC, 0.75) resulted in an AUC of 0.84. When including healthy control participants, RRT-mean had an adjusted OR of 12.4 and the AUC of the combined model (RRT-mean and platelet count) was 0.90. DATA CONCLUSION: Prolonged RRT values and low platelet count were significantly associated with the presence of PVT in cirrhotic participants. RRT values derived from 4D Flow MRI may have potential clinical relevance in the management of PVT. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

DOI： 10.1002/jmri.29357

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Neurofluids is a term introduced to define all fluids in the brain and spine such as blood, cerebrospinal fluid, and interstitial fluid. Neuroscientists in the past millennium have steadily identified the several different fluid environments in the brain and spine that interact in a synchronized harmonious manner to assure a healthy microenvironment required for optimal neuroglial function. Neuroanatomists and biochemists have provided an incredible wealth of evidence revealing the anatomy of perivascular spaces, meninges and glia and their role in drainage of neuronal waste products. Human studies have been limited due to the restricted availability of noninvasive imaging modalities that can provide a high spatiotemporal depiction of the brain neurofluids. Therefore, animal studies have been key in advancing our knowledge of the temporal and spatial dynamics of fluids, for example, by injecting tracers with different molecular weights. Such studies have sparked interest to identify possible disruptions to neurofluids dynamics in human diseases such as small vessel disease, cerebral amyloid angiopathy, and dementia. However, key differences between rodent and human physiology should be considered when extrapolating these findings to understand the human brain. An increasing armamentarium of noninvasive MRI techniques is being built to identify markers of altered drainage pathways. During the three-day workshop organized by the International Society of Magnetic Resonance in Medicine that was held in Rome in September 2022, several of these concepts were discussed by a distinguished international faculty to lay the basis of what is known and where we still lack evidence. We envision that in the next decade, MRI will allow imaging of the physiology of neurofluid dynamics and drainage pathways in the human brain to identify true pathological processes underlying disease and to discover new avenues for early diagnoses and treatments including drug delivery. Evidence level: 1 Technical Efficacy: Stage 3.

DOI： 10.1002/jmri.28759

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Oxford University Press (OUP)  

Abstract

This review provides an overview of the application of artificial intelligence (AI) in radiation therapy (RT) from a radiation oncologist’s perspective. Over the years, advances in diagnostic imaging have significantly improved the efficiency and effectiveness of radiotherapy. The introduction of AI has further optimized the segmentation of tumors and organs at risk, thereby saving considerable time for radiation oncologists. AI has also been utilized in treatment planning and optimization, reducing the planning time from several days to minutes or even seconds. Knowledge-based treatment planning and deep learning techniques have been employed to produce treatment plans comparable to those generated by humans. Additionally, AI has potential applications in quality control and assurance of treatment plans, optimization of image-guided RT and monitoring of mobile tumors during treatment. Prognostic evaluation and prediction using AI have been increasingly explored, with radiomics being a prominent area of research. The future of AI in radiation oncology offers the potential to establish treatment standardization by minimizing inter-observer differences in segmentation and improving dose adequacy evaluation. RT standardization through AI may have global implications, providing world-standard treatment even in resource-limited settings. However, there are challenges in accumulating big data, including patient background information and correlating treatment plans with disease outcomes. Although challenges remain, ongoing research and the integration of AI technology hold promise for further advancements in radiation oncology.

DOI： 10.1093/jrr/rrad090

Web of Science

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.rev.2022-0012

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this review, we address the issue of fairness in the clinical integration of artificial intelligence (AI) in the medical field. As the clinical adoption of deep learning algorithms, a subfield of AI, progresses, concerns have arisen regarding the impact of AI biases and discrimination on patient health. This review aims to provide a comprehensive overview of concerns associated with AI fairness; discuss strategies to mitigate AI biases; and emphasize the need for cooperation among physicians, AI researchers, AI developers, policymakers, and patients to ensure equitable AI integration. First, we define and introduce the concept of fairness in AI applications in healthcare and radiology, emphasizing the benefits and challenges of incorporating AI into clinical practice. Next, we delve into concerns regarding fairness in healthcare, addressing the various causes of biases in AI and potential concerns such as misdiagnosis, unequal access to treatment, and ethical considerations. We then outline strategies for addressing fairness, such as the importance of diverse and representative data and algorithm audits. Additionally, we discuss ethical and legal considerations such as data privacy, responsibility, accountability, transparency, and explainability in AI. Finally, we present the Fairness of Artificial Intelligence Recommendations in healthcare (FAIR) statement to offer best practices. Through these efforts, we aim to provide a foundation for discussing the responsible and equitable implementation and deployment of AI in healthcare.

DOI： 10.1007/s11604-023-01474-3

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Scopus

PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1097/RLI.0000000000000969

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND AND PURPOSE: Impaired glymphatic function has been suggested to be implicated in the pathophysiology of MS and aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder. This study aimed to investigate the interstitial fluid dynamics in the brain in patients with myelin oligodendrocyte glycoprotein antibody disorders (MOGAD), another demyelinating disorder, using a noninvasive imaging technique called the diffusivity along the perivascular space (ALPS) index. MATERIALS AND METHODS: A prospective study was conducted on 16 patients with MOGAD in remission and 22 age- and sex-matched healthy control subjects. MR imaging was performed using a 3T scanner, and the ALPS index was calculated using diffusion MR imaging data with a b-value of 1000 s/mm2. The ALPS index and gray matter volumes were compared between the 2 groups, and these parameters were correlated with the Expanded Disability Status Scale. RESULTS: The mean ALPS index of patients with MOGAD was significantly lower than that of healthy controls (Cohen d = 0.93, false discovery rate-corrected P = .02). The lower mean ALPS index was significantly associated with a worse Expanded Disability Status Scale score (Spearman ρ = -0.51; 95% CI, -0.85 to -0.02; P = .03). However, cortical volume and deep gray matter volume were not significantly different between the 2 groups, and they were not correlated with the Expanded Disability Status Scale. CONCLUSIONS: This study suggests that patients with MOGAD may have impaired glymphatic function, as measured by the ALPS index, which is associated with patient disability. Further study is warranted with a larger sample size.

DOI： 10.3174/ajnr.A8066

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.mp.2022-0110

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2147/NSS.S448871

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fnagi.2024.1362457

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

An artificial intelligence (AI) system that reconstructs virtual 3D thin-section CT (TSCT) images from conventional CT images by applying deep learning was developed. The aim of this study was to investigate whether virtual and real TSCT could measure the solid size of early-stage lung adenocarcinoma. The pair of original thin-CT and simulated thick-CT from the training data with TSCT images (thickness, 0.5-1.0 mm) of 2700 pulmonary nodules were used to train the thin-CT generator in the generative adversarial network (GAN) framework and develop a virtual TSCT AI system. For validation, CT images of 93 stage 0-I lung adenocarcinomas were collected, and virtual TSCTs were reconstructed from conventional 5-mm thick-CT images using the AI system. Two radiologists measured and compared the solid size of tumors on conventional CT and virtual and real TSCT. The agreement between the two observers showed an almost perfect agreement on the virtual TSCT for solid size measurements (intraclass correlation coefficient = 0.967, P < 0.001, respectively). The virtual TSCT had a significantly stronger correlation than that of conventional CT (P = 0.003 and P = 0.001, respectively). The degree of agreement between the clinical T stage determined by virtual TSCT and the clinical T stage determined by real TSCT was excellent in both observers (k = 0.882 and k = 0.881, respectively). The AI system developed in this study was able to measure the solid size of early-stage lung adenocarcinoma on virtual TSCT as well as on real TSCT.

DOI： 10.1038/s41598-023-48755-5

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PubMed

担当区分：筆頭著者   記述言語：日本語  

担当区分：筆頭著者,　責任著者   記述言語：日本語  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.bc.2023-0122

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.diii.2023.06.011

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We aimed to elucidate the distribution pattern of the positron emission tomography probe [18F]THK 5351, a marker for astrogliosis and tau accumulation, in healthy aging. We also assessed the relationship between THK5351 retention and resting state networks. We enrolled 62 healthy participants in this study. All participants underwent magnetic resonance imaging/positron emission tomography scanning consisting of T1-weighted images, resting state functional magnetic resonance imaging, Pittsburgh Compound-B and THK positron emission tomography. The preprocessed THK images were entered into a scaled subprofile modeling/principal component analysis to extract THK distribution patterns. Using the most significant THK pattern, we generated regions of interest, and performed seed-based functional connectivity analyses. We also evaluated the functional connectivity overlap ratio to identify regions with high between-network connectivity. The most significant THK distributions were observed in the medial prefrontal cortex and bilateral putamen. The seed regions of interest in the medial prefrontal cortex had a functional connectivity map that significantly overlapped with regions of the dorsal default mode network. The seed regions of interest in the putamen showed strong overlap with the basal ganglia and anterior salience networks. The functional connectivity overlap ratio also showed that three peak regions had the characteristics of connector hubs. We have identified an age-related spatial distribution of THK in the medial prefrontal cortex and basal ganglia in normal aging. Interestingly, the distribution's peaks are located in regions of connector hubs that are strongly connected to large-scale resting state networks associated with higher cognitive function.

DOI： 10.18999/nagjms.85.4.758

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

The radiopharmaceutical 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) has been dominantly used in positron emission tomography (PET) scans for over 20 years, and due to its vast utility its applications have expanded and are continuing to expand into oncology, neurology, cardiology, and infectious/inflammatory diseases. More recently, the addition of artificial intelligence (AI) has enhanced nuclear medicine diagnosis and imaging with FDG-PET, and new radiopharmaceuticals such as prostate-specific membrane antigen (PSMA) and fibroblast activation protein inhibitor (FAPI) have emerged. Nuclear medicine therapy using agents such as [177Lu]-dotatate surpasses conventional treatments in terms of efficacy and side effects. This article reviews recently established evidence of FDG and non-FDG drugs and anticipates the future trajectory of nuclear medicine.

DOI： 10.1007/s12149-023-01865-6

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.21203/rs.3.rs-3411760/v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1007/s11604-023-01432-z

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Although there is no solid agreement for artificial intelligence (AI), it refers to a computer system with intelligence similar to that of humans. Deep learning appeared in 2006, and more than 10 years have passed since the third AI boom was triggered by improvements in computing power, algorithm development, and the use of big data. In recent years, the application and development of AI technology in the medical field have intensified internationally. There is no doubt that AI will be used in clinical practice to assist in diagnostic imaging in the future. In qualitative diagnosis, it is desirable to develop an explainable AI that at least represents the basis of the diagnostic process. However, it must be kept in mind that AI is a physician-assistant system, and the final decision should be made by the physician while understanding the limitations of AI. The aim of this article is to review the application of AI technology in diagnostic imaging from PubMed database while particularly focusing on diagnostic imaging in thorax such as lesion detection and qualitative diagnosis in order to help radiologists and clinicians to become more familiar with AI in thorax.

DOI： 10.1007/s11547-023-01691-w

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PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(一社)日本神経学会  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Regional anatomical structures of the brain are intimately connected to functions corresponding to specific regions and the temporospatial pattern of genetic expression and their functions from the fetal period to old age. Therefore, quantitative brain morphometry has often been employed in neuroscience investigations, while controlling for the scanner effect of the scanner is a critical issue for ensuring accuracy in brain morphometric studies of rare orphan diseases due to the lack of normal reference values available for multicenter studies. This study aimed to provide across-site normal reference values of global and regional brain volumes for each sex and age group in children and adolescents. We collected magnetic resonance imaging (MRI) examinations of 846 neurotypical participants aged 6.0-17.9 years (339 male and 507 female participants) from 5 institutions comprising healthy volunteers or neurotypical patients without neurological disorders, neuropsychological disorders, or epilepsy. Regional-based analysis using the CIVET 2.1.0. pipeline provided regional brain volumes, and the measurements were across-site combined using ComBat-GAM harmonization. The normal reference values of global and regional brain volumes and lateral indices in our study could be helpful for evaluating the characteristics of the brain morphology of each individual in a clinical setting and investigating the brain morphology of ultra-rare diseases.

DOI： 10.3390/diagnostics13172774

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background Percutaneous transhepatic portal vein (PV) embolization (PVE) is a standard preoperative procedure for advanced biliary cancer when the future liver remnant (FLR) is insufficient, yet the effect of this procedure on portal hemodynamics is still unclear. Purpose To assess whether four-dimensional (4D) MRI flowmetry can be used to estimate FLR volume and to identify the optimal time for this measurement. Materials and Methods This prospective single-center study enrolled consecutive adult patients with biliary cancer who underwent percutaneous transhepatic PVE for the right liver between June 2020 and November 2022. Portal hemodynamics were assessed using 4D flow MRI before PVE and within 1 day (0-day group) or 3-4 days (3-day group) after PVE. FLR volume was measured using CT before PVE and after PVE but before surgery. Blood flow changes were analyzed with the Wilcoxon signed rank test, and correlations with Spearman rank correlation. Results The 0-day group included 24 participants (median age, 72 years [IQR, 69-77 years]; 17 male participants), and the 3-day group included 13 participants (median age, 71 years [IQR, 68-78 years]; eight male participants). Both groups showed increased left PV (LPV) flow rate after PVE (0-day group: from median 3.72 mL/sec [IQR, 2.83-4.55 mL/sec] to 9.48 mL/sec [IQR, 8.12-10.7 mL/sec], P < .001; 3-day group: from median 3.65 mL/sec [IQR, 2.14-3.79 mL/sec] to 8.16 mL/sec [IQR, 6.82-8.98 mL/sec], P < .001). LPV flow change correlated with FLR volume change relative to the number of days from PVE to presurgery CT only in the 3-day group (ρ = 0.62, P = .02; 0-day group, P = .11). The output of the regression equation for estimating presurgery FLR volume correlated with CT-measured volume (ρ = 0.78; P = .002). Conclusion Four-dimensional flow MRI demonstrated increased blood flow in residual portal branches 3-4 days after PVE, offering insights for estimating presurgery FLR volume. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Roldán-Alzate and Oechtering in this issue.

DOI： 10.1148/radiol.230709

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-023-01412-3

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The prognosis and prognostic factors of patients receiving whole-brain radiotherapy (WBRT) for leptomeningeal metastasis (LM) from lung adenocarcinoma have not been established. Particularly, the impact of EGFR mutations and ALK rearrangements on survival remains unclear. This retrospective study evaluated the prognosis and prognostic factors of patients receiving WBRT for LM. We evaluated overall survival (OS) from WBRT initiation and clinical variables in 80 consecutive patients receiving WBRT for LM from lung adenocarcinoma at our institution between June 2013 and June 2021. After a median follow-up of 5.2 (range 0.5-56.5) months, the median OS was 6.2 months (95% CI 4.4-12.4). Of the 80 patients, 51 were classified as EGFR/ALK mutant (EGFR: 44; ALK: 6; both: 1) and 29 as wild-type. The median OS was 10.4 (95% CI 5.9-20.9) versus 3.8 (95% CI 2.5-7.7) months in the EGFR/ALK-mutant versus wild-type patients (HR = 0.49, P = 0.0063). Multivariate analysis indicated that EGFR/ALK alterations (HR = 0.54, P = 0.021) and Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-1 (HR = 0.25, P < 0.001) were independent factors associated with favorable OS. Among the patients who underwent brain MRI before and after WBRT, intracranial progression-free survival was longer in the 26 EGFR/ALK-mutant than 13 wild-type patients (HR = 0.31, P = 0.0039). Although the prognosis of patients receiving WBRT for LM remains poor, EGFR/ALK alterations and good ECOG PS may positively impact OS in those eligible for WBRT.

DOI： 10.1007/s10585-023-10225-7

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Objectives

Standardised uptake value ratio (SUVR) is usually obtained by dividing the SUV of the region of interest (ROI) by that of the cerebellar cortex. Cerebellar cortex is not a valid reference in cases where amyloid β deposition or lesions are present. Only few studies have evaluated the use of other regions as references. We compared the validity of the pons and corpus callosum as reference regions for the quantitative evaluation of brain positron emission tomography (PET) using ¹¹C-PiB compared to the cerebellar cortex.

Methods

We retrospectively evaluated data from 86 subjects with or without Alzheimer’s disease (AD). All subjects underwent magnetic resonance imaging, PET imaging, and cognitive function testing. For the quantitative analysis, three-dimensional ROIs were automatically placed, and SUV and SUVR were obtained. We compared these values between AD and healthy control (HC) groups.

Results

SUVR data obtained using the pons and corpus callosum as reference regions strongly correlated with that using the cerebellar cortex. The sensitivity and specificity were high when either the pons or corpus callosum was used as the reference region. However, the SUV values of the corpus callosum were different between AD and HC (p &lt; 0.01).

Conclusions

Our data suggest that the pons and corpus callosum might be valid reference regions.

DOI： 10.1007/s12149-023-01843-y

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PubMed

その他リンク： https://link.springer.com/article/10.1007/s12149-023-01843-y/fulltext.html

担当区分：筆頭著者   記述言語：日本語  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

This review outlines the current status and challenges of the clinical applications of artificial intelligence in liver imaging using computed tomography or magnetic resonance imaging based on a topic analysis of PubMed search results using latent Dirichlet allocation. LDA revealed that “segmentation,” “hepatocellular carcinoma and radiomics,” “metastasis,” "fibrosis," and "reconstruction" were current main topic keywords. Automatic liver segmentation technology using deep learning is beginning to assume new clinical significance as part of whole-body composition analysis. It has also been applied to the screening of large populations and the acquisition of training data for machine learning models and has resulted in the development of imaging biomarkers that have a significant impact on important clinical issues, such as the estimation of liver fibrosis, recurrence, and prognosis of malignant tumors. Deep learning reconstruction is expanding as a new technological clinical application of artificial intelligence and has shown results in reducing contrast and radiation doses. However, there is much missing evidence, such as external validation of machine learning models and the evaluation of the diagnostic performance of specific diseases using deep learning reconstruction, suggesting that the clinical application of these technologies is still in development.

DOI： 10.1007/s11547-023-01638-1

Web of Science

Scopus

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s11060-023-04358-8

Web of Science

PubMed

その他リンク： https://link.springer.com/article/10.1007/s11060-023-04358-8/fulltext.html

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(一社)日本磁気共鳴医学会  

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

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Otitis media with antineutrophil cytoplasmic antibody-associated vasculitis (OMAAV) has been proposed as a new type of otitis media. The hearing loss caused by OMAAV can be expected to improve with early detection and intervention, but if it continues to worsen and leads to deafness, it is challenging to recover the patient's hearing. When bilateral deafness occurs, cochlear implant (CI) surgery is the only way to improve hearing. Here, Case 1 showed unilateral cochlear calcification, and Case 2 showed bilateral cochlear calcification. In Case 1, CI surgery was performed on the ear lacking calcification, and in Case 2 it was performed on the ear with milder calcification. In Case 2, granulation was present from the tympanic space to the mastoid, the round window was closed, and the basal turn of the cochlea was narrowed. Such calcification of the cochlea caused by OMAAV has not been reported so far. It is essential to detect these changes by computed tomography scans at an early stage and to perform CI surgery at an appropriate time, because hearing improvements are not expected in patients who become deaf because of OMAAV.

DOI： 10.1016/j.anl.2022.01.004

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Although endovascular aneurysmal repair (EVAR) is a preferred treatment for abdominal aortic aneurysm (AAA) owing to its low invasiveness, its impact on the local hemodynamics has not been fully assessed. PURPOSE: To elucidate how EVAR affects the local hemodynamics in terms of energy loss (EL). STUDY TYPE: Prospective single-arm study. FIELD STRENGTH/SEQUENCE: A 3.0 T/4D flow MRI using a phase-contrast three-dimensional cine-gradient-echo sequence. POPULATION: A total of 13 consecutive patients (median [interquartile range] age: 77.0 [73.0, 78.8] years, 11 male) scheduled for EVAR as an initial treatment for fusiform AAA. ASSESSMENT: 4D flow MRI covering the abdominal aorta and bilateral common iliac arteries and the corresponding stent-graft (SG) lumen was performed before and after EVAR. Plasma brain natriuretic peptide (BNP) was measured within 1 week before and 1 month after EVAR. The hemodynamic data, including mean velocity and the local EL, were compared pre-/post-EVAR. EL was correlated with AAA neck angle and with BNP. Patients were subdivided into deformed (N = 5) and undeformed SG subgroups (N = 8) and pre-/post-EVAR BNP compared in each. STATISTICS: Parametric or nonparametric methods. Spearman's rank correlation coefficients (r). The interobserver/intraobserver variabilities with Bland-Altman plots. A P value < 0.05 is considered significant. RESULTS: The mean velocity (cm/sec) at the AAA was five times greater after EVAR: 4.79 ± 0.32 vs. 0.91 ± 0.02. The total EL (mW) increased by 1.7 times after EVAR: 0.487 (0.420, 0.706) vs. 0.292 (0.192, 0.420). The total EL was proportional to the AAA neck angle pre-EVAR (r = 0.691) and post-EVAR (r = 0.718). BNP (pg/mL) was proportional to the total EL post-EVAR (r = 0.773). In the deformed SG group, EL (0.349 [0.261, 0.416]) increased 2.4-fold to 0.848 (0.597, 1.13), and the BNP 90.3 (53.6, 105) to 100 (67.2, 123) post-EVAR. CONCLUSION: The local EL showed a 1.7-fold increase after EVAR. The larger increase in the EL in the deformed SG group might be a potential concern for frail patients. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 2.

DOI： 10.1002/jmri.28359

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PubMed

記述言語：日本語  

担当区分：筆頭著者   記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

Background and purpose

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

Materials and methods

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

Results

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

Conclusion

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

DOI： 10.3389/fneur.2023.1100736

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1016/j.nbd.2023.105990

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PubMed

担当区分：最終著者  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3233/VES-190662

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: To elucidate MRI features of primary hepatic mucosa-associated lymphoid tissue (MALT) lymphoma, particularly, the "speckled enhancement" on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI. METHODS: The institutional review board approved this retrospective observational study and waived informed consent. Using our picture archiving and communication systems and electronic medical records, five patients histopathologically diagnosed as hepatic MALT lymphoma and clinically confirmed as primary lesions who had undergone dynamic contrast-enhanced (DCE)-CT and DCE-MRI with Gd-EOB-DTPA were identified from September 2009 to December 2020. Two radiologists assessed their CT and MRI data in consensus with a pathologist's advice. RESULTS: Overall, five lesions in five patients were included in this study. Precontrast CT showed hypoattenuation in all lesions. In the arterial phase of DCE-CT, four lesions (80%) showed hyperattenuation, whereas all lesions showed iso- to hypoattenuation in the delayed phase. A vessel penetration sign was also observed in all lesions. On MRI, all lesions showed hypointensity on T1-weighted images, hyperintensity on T2-weighted images, and restricted diffusion on diffusion-weighted images. Both DCE-CT and DCE-MRI with Gd-EOB-DTPA showed similar enhancement patterns, except for the hepatocyte phase. Notably, however, four out of five lesions showed characteristic "speckled enhancement" that refers to punctate positive enhancements within the low signal lesions on the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI pathologically confirmed to be hepatocyte clusters that remained in the tumor. CONCLUSION: Primary hepatic MALT lymphomas were characterized by arterial phase enhancement, restricted diffusion, vessel penetration sign, and more specifically "speckled enhancement" in the hepatobiliary phase of DCE-MRI with Gd-EOB-DTPA.

DOI： 10.2463/mrms.mp.2021-0069

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2021-0100

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2022-0017

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

A man in his 50s with Budd-Chiari syndrome diagnosed with the suprahepatic inferior vena cava (IVC) obstruction on CT was assessed using 4D Flow MRI before and after balloon angioplasty. 4D Flow MRI acquired in two respiratory phases, depicted complex hemodynamic and respiratory variability, and a jet stream at the narrowed channel of the membranous IVC. Post-interventional 4D Flow MRI showed that the IVC blood flow increased with corrected flow directions in the infrarenal IVC.

DOI： 10.2463/mrms.ici.2021-0110

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.bc.2021-0141

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Society for Magnetic Resonance in Medicine  

DOI： 10.2463/mrms.rev.2023-0047

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Currently, the standard curative treatment for ventricular tachycardia (VT) and ventricular fibrillation (VF) is radiofrequency catheter ablation. However, when the VT circuit is deep in the myocardium, the catheter may not be delivered, and a new, minimally invasive treatment using different energies is desired. METHODS: This is a protocol paper for a feasibility study designed to provide stereotactic radiotherapy for refractory VT not cured by catheter ablation after at least one catheter ablation. The primary end point is to evaluate the short-term safety of this treatment and the secondary endpoint is to evaluate its efficacy as assessed by the reduction in VT episode. Cyberknife M6 radiosurgery system will be used for treatment, and the prescribed dose to the target will be 25Gy in one fraction. The study will be conducted on three patients. CONCLUSION: Since catheter ablation is the only treatment option for VT that is covered by insurance in Japan, there is currently no other treatment for VT/VF that cannot be cured by catheter ablation. We hope that this feasibility study will provide hope for patients who are currently under the stress of ICD activation. TRIAL REGISTRATION: The study has been registered in the Japan Registry of Clinical Trials (jRCTs042230030).

DOI： 10.12688/f1000research.138758.2

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1212/WNL.0000000000201300

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s12194-022-00670-6

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PubMed

その他リンク： https://link.springer.com/article/10.1007/s12194-022-00670-6/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We evaluated the inner ear distribution of 17O-labeled saline administered to the human tympanic cavity. Magnetic resonance imaging was performed after intratympanic administration in five healthy volunteers and one patient with cochlear endolymphatic hydrops. In all volunteers, 17O-labeled water permeated the cochlear basal turn and vestibule at 30 min and disappeared gradually within 2-4 h. All participants experienced positional vertigo lasting a few hours to a few days. Visualization of 17O-labeled water distribution in the endolymphatic space of the posterior ampulla showed indistinct separation of endolymph and perilymph in the cochlea and most of the vestibule in all participants. Intralabyrinthine distribution of 17O-labeled water differed from that in previous reports of intratympanically administered gadolinium-based contrast agent. 17O-labeled water in the endolymphatic space may cause heavier endolymph and positional vertigo. These results of this study may add new insights for investigating the distribution and the effects of molecules in the inner ear after the intratympanic administration in living humans.

DOI： 10.3389/fneur.2022.1016577

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Thus far, ultrasound, CT, and 2D cine phase-contrast MRI has been adopted to evaluate blood flow and vascular morphology in the portal venous system; however, all these techniques have some shortcomings, such as limited field of view and difficulty in accurately evaluating blood flow. A new imaging technique, namely 3D cine phase-contrast (4D Flow) MRI, can acquire blood flow data of the entire abdomen at once and in a time-resolved manner, allowing visual, quantitative, and comprehensive assessment of blood flow in the portal venous system. In addition, a retrospective blood flow analysis, i.e., "retrospective flowmetry," is possible. Although the development of 4D Flow MRI for the portal system has been delayed compared to that for the arterial system owing to the lower flow velocity of the portal venous system and the presence of respiratory artifacts, several useful reports have recently been published as the technology has advanced. In the first part of this narrative review article, technical considerations of image acquisition and analysis methods of 4D Flow MRI for the portal venous system and the validations of their results are described. In the second part, the current clinical application of 4D Flow MRI for the portal venous system is reviewed.

DOI： 10.1007/s11547-022-01553-x

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background Changing iodinated contrast media (ICM) may reduce the risk of recurrent ICM-induced hypersensitivity reactions in patients with a prior reaction. Purpose To perform a systematic review on the effectiveness of ICM change in comparison with no change to prevent recurrent ICM immediate hypersensitivity reactions. Materials and methods Multiple data bases were searched without language restriction between January 1990 and August 2021 to identify comparative studies of any design that included patients with a prior ICM hypersensitivity reaction to low-osmolality ICM and re-exposure to intravascular ICM. The methods used included a duplicate assessment of eligibility, double extraction of quantitative data, validity assessment, and random-effects meta-analysis. The primary outcome was the incidence of all-grade immediate recurrent hypersensitivity reactions. Secondary outcomes were the incidence of severe immediate recurrent hypersensitivity reactions and other adverse events associated with ICM change. Results Six retrospective observational studies at moderate to severe risk of bias assessed 7155 adult patients (4329 in the ICM change group and 2826 in the no-change group). Studies adopted nonstandardized switching methods, and the proportions of the ICM change group ranged between 19% (five of 27 examinations) and 80% (3104 of 3880 examinations). A Bayesian meta-analysis revealed that changing ICM was associated with a reduced risk of recurrent hypersensitivity reaction by 61% (risk ratio = 0.39; 95% credible interval [CrI]: 0.24, 0.58). The wide-ranging estimates of risk reduction were not explained by the risk of bias ratings, the event rates in the no-change group, the index-reaction severity, or the co-administered nonstandard premedication. Rare severe recurrent reactions (five studies with five events) precluded a conclusion (risk ratio = 0.34, favoring ICM change; CrI: 0.01, 3.74). Adverse events associated with ICM change were not reported. Conclusion In observational evidence of limited quality, iodinated contrast media (ICM)-change was associated with a reduced risk of recurrent immediate hypersensitivity reaction in patients with a prior ICM-induced hypersensitivity reaction. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by McDonald in this issue.

DOI： 10.1148/radiol.220370

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1007/s11604-022-01281-2

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: The purpose of this study was to evaluate the interstitial fluid status in a wide range of age groups using diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, which is a simplified variation of diffusion tensor image analysis along the perivascular space (DTI-ALPS). MATERIALS AND METHODS: This retrospective study included data from 128 patients who underwent clinical magnetic resonance imaging (MRI) studies, including DWI, and were found to have no abnormal findings in the brain on MRI. Three motion-probing gradients of the DWI were applied in an orthogonal direction to the imaging plane. Apparent diffusion coefficient images in the x-, y-, and z-axes were retrospectively generated, and composite color images were created to locate the projection and association fiber area on the slice including the body of the lateral ventricle. ALPS indices were calculated, and correlations with age were evaluated using linear and second-degree regression analysis. Linear regression analysis was also performed for a subgroup of patients older than 40 years. In addition, an analysis of variance (ANOVA) test among the generations was performed. RESULTS: The linear regression analysis between age and the ALPS index showed a correlation coefficient of -0.20 for all age group and -0.51 for the subgroup older than 40 years. The second-degree regression analysis showed a correlation coefficient of 0.39. ANOVA showed that the 40's generation showed a statistically significant higher value of ALPS index compared to all other generations except for the 30's generation. While, the 70's generation showed a statistically significant lower value of the ALPS index compared to all other generations. CONCLUSIONS: The analysis of the DWI-APLS method showed a correlation between age and the ALPS index in second-degree distribution which peaked in the 40's generation. This finding in normal subjects may be fundamental in the analysis of disease cases. We tried to evaluate the glymphatic system status in a wide range of age groups using diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, and the results showed a correlation between age and the ALPS index in second-degree distribution which peaked in the 40's generation.

DOI： 10.1007/s11604-022-01275-0

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PubMed

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：断層映像研究会  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

We aim to evaluate the basic characteristics of SRS MapCHECK (SRSMC) for CyberKnife (CK) and establish a dose verification system using SRSMC for the tumor-tracking irradiation for CK. The field size and angular dependence of SRSMC were evaluated for basic characterization. The output factors (OPFs) and absolute doses measured by SRSMC were compared with those measured using microDiamond and microchamber detectors and those calculated by the treatment planning system (TPS). The angular dependence was evaluated by comparing the SRSMC with a microchamber. The tumor-tracking dose verification system consists of SRSMC and a moving platform. The doses measured using SRSMC were compared with the doses measured using a microchamber and radiochromic film. The OPFs and absolute doses of SRSMC were within ±3.0% error for almost all field sizes, and the angular dependence was within ±2.0% for all incidence angles. The absolute dose errors between SRSMC and TPS tended to increase when the field size was smaller than 10 mm. The absolute doses of the tumor-tracking irradiation measured using SRSMC and those measured using a microchamber agreed within 1.0%, and the gamma pass rates of SRSMC in comparison with those of the radiochromic film were greater than 95%. The basic characteristics of SRSMC for CK presented acceptable results for clinical use. The results of the tumor-tracking dose verification system realized using SRSMC were equivalent to those of conventional methods, and this system is expected to contribute toward improving the efficiency of quality control in many facilities.

DOI： 10.1002/acm2.13645

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1002/jmri.28117

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Cureus, Inc.  

DOI： 10.7759/cureus.25888

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

With the widespread use of three-dimensional printers, organ models created by these printers are now being used in the medical field for preoperative planning of surgeries. In this article, we report two cases in which embolization was expected to be difficult, and the three-dimensional printer-based vascular modeling was helpful in planning the surgery. The first case involved an aneurysm of the splenic artery. We attempted to embolize the aneurysm but were unable to advance the catheter into the distal artery and discontinued the procedure. The second case was a perianal varicose vein, which was initially treated with percutaneous transhepatic obliteration but was recanalized and required embolization. However, we expected difficulty in selecting the inferior mesenteric vein. In both cases, the vascular models were created using a 3D printer from the patients' computed tomography images. Preoperative planning, including treatment simulation, was based on these models. The time required to print a three-dimensional vascular model was approximately 12 hours at a cost of less than $10 each. Patient-specific vascular models using a three-dimensional printer can be a simple and inexpensive tool that can increase the success of embolization in difficult cases.

DOI： 10.18999/nagjms.84.2.477

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11547-022-01486-5

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

3D cine phase-contrast (4D flow) MRI is a sequence with great potential for non-invasive time-resolved 3D flowmetry at arbitrary vessel sections in various blood vessels. However, it is not widely known that the flowmetry with 4D flow MRI is vulnerable to pulsatile and non-uniform flow. Due to the limited spatial and temporal resolutions, averaging within the 3D voxel is occurring during the flowmetry. A simple solution is to avoid setting the measurement plane in the area where non-uniform flow is dominant, which is possible with an aid of streamline depictions generated by computational fluid dynamics (CFD) or 4D flow MRI data. Unlike 4D flow MRI, flowmetry in CFD simulation can use higher spatial and temporal resolution depending on computer performance; therefore, it is robust to fluctuating non-uniform flow. However, the performance of CFD simulations might be limited due to inlet conditions with low temporal resolution. Difficulty applying complex blood flow such as reflection flow from periphery may also limit accurate simulation. Caution should be taken when comparing the result of CFD simulation to that of 4D flow measurement.

DOI： 10.2463/mrms.rev.2021-0099

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1016/j.ejmp.2022.01.003

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PubMed

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本放射線技術学会  

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本放射線技術学会  

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本放射線技術学会  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.3389/fneur.2022.843883

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PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本医学放射線学会  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1007/s11604-021-01187-5

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.18999/nagjms.84.1.29

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1097/MAO.0000000000003328

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1007/s12282-021-01294-1

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Breast magnetic resonance imaging (MRI) is the most sensitive imaging modality for breast cancer diagnosis and is widely used clinically. Dynamic contrast-enhanced MRI is the basis for breast MRI, but ultrafast images, T2-weighted images, and diffusion-weighted images are also taken to improve the characteristics of the lesion. Such multiparametric MRI with numerous morphological and functional data poses new challenges to radiologists, and thus, new tools for reliable, reproducible, and high-volume quantitative assessments are warranted. In this context, radiomics, which is an emerging field of research involving the conversion of digital medical images into mineable data for clinical decision-making and outcome prediction, has been gaining ground in oncology. Recent development in artificial intelligence has promoted radiomics studies in various fields including breast cancer treatment and numerous studies have been conducted. However, radiomics has shown a translational gap in clinical practice, and many issues remain to be solved. In this review, we will outline the steps of radiomics workflow and investigate clinical application of radiomics focusing on breast MRI based on published literature, as well as current discussion about limitations and challenges in radiomics.

DOI： 10.1007/s11547-021-01423-y

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The aging brain undergoes structural changes even in very healthy individuals. Quantifying these changes could help disentangle pathological changes from those associated with the normal human aging process. Using longitudinal MRI data from 227 carefully selected healthy human cohort with age ranging from 50 to 80 years old at baseline scan, we quantified age-related volumetric changes in the brain of healthy human older adults. Longitudinally, the rates of tissue loss in total gray matter (GM) and white matter were 2,497.5 mm3 per year and 2,579.8 mm3 per year, respectively. Across the whole brain, the rates of GM decline varied with regions in the frontal and parietal lobes having faster rates of decline, whereas some regions in the occipital and temporal lobes appeared relatively preserved. In contrast, cross sectional changes were mainly observed in the temporal-occipital regions. Similar longitudinal atrophic changes were also observed in subcortical regions including thalamus, hippocampus, putamen, and caudate, whereas the pallidum showed an increasing volume with age. Overall, regions maturing late in development (frontal, parietal) are more vulnerable to longitudinal decline, whereas those that fully mature in the early stage (temporal, occipital) are mainly affected by cross sectional changes in healthy older cohort. This may suggest that, for a successful healthy aging, the former needs to be maximally developed at an earlier age to compensate for the longitudinal decline later in life and the latter to remain relatively preserved even in old age, consistent with both concepts of reserve and brain maintenance.Significance StatementAging is associated with gray matter (GM) decline, yet some individuals tend to remain cognitively healthy even in advanced age. What differentiates the brains of "healthy agers" from those individuals who are prone to faster cognitive decline still remains unclear. Using longitudinal MRI data from a carefully selected cohort, we examined the brain aging characteristics of healthy agers. Our findings showed that, even in this population, frontal-parietal regions have faster longitudinal rate of GM decline, whereas some temporal-occipital regions appeared relatively preserved. These findings may suggest that, for a successful healthy aging, frontal-parietal regions need to be maximally developed to compensate for the longitudinal decline later in life and the temporal-occipital regions to remain relatively preserved even in old age.

DOI： 10.1523/ENEURO.0455-21.2022

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Society of Neuroradiology ({ASNR})  

DOI： 10.3174/ajnr.A7334

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PubMed

担当区分：筆頭著者,　最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.rev.2020-0122

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PubMed

担当区分：筆頭著者,　最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2021-0010

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PubMed

担当区分：筆頭著者,　最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.ici.2021-0022

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: The estimation of functional connectivity (FC) measures using resting state functional MRI (fMRI) is often affected by head motion during functional imaging scans. Head motion is more common in the elderly than in young participants and could therefore affect the evaluation of age-related changes in brain networks. Thus, this study aimed to investigate the influence of head motion in FC estimation when evaluating age-related changes in brain networks. METHODS: This study involved 132 healthy volunteers divided into 3 groups: elderly participants with high motion (OldHM, mean age (±SD) = 69.6 (±5.31), N = 44), elderly participants with low motion (OldLM, mean age (±SD) = 68.7 (±4.59), N = 43), and young adult participants with low motion (YugLM, mean age (±SD) = 27.6 (±5.26), N = 45). Head motion was quantified using the mean of the framewise displacement of resting state fMRI data. After preprocessing all resting state fMRI datasets, several resting state networks (RSNs) were extracted using independent component analysis (ICA). In addition, several network metrics were also calculated using network analysis. These FC measures were then compared among the 3 groups. RESULTS: In ICA, the number of voxels with significant differences in RSNs was higher in YugLM vs. OldLM comparison than in YugLM vs. OldHM. In network analysis, all network metrics showed significant (P < 0.05) differences in comparisons involving low vs. high motion groups (OldHM vs. OldLM and OldHM vs. YugLM). However, there was no significant (P > 0.05) difference in the comparison involving the low motion groups (OldLM vs. YugLM). CONCLUSION: Our findings showed that head motion during functional imaging could significantly affect the evaluation of age-related brain network changes using resting state fMRI data.

DOI： 10.2463/mrms.mp.2020-0081

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Society for Magnetic Resonance in Medicine  

DOI： 10.2463/mrms.mp.2020-0121

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Extra-cardiovascular incidental findings (IFs) on preoperative computed tomography (CT) are frequently observed in transcatheter aortic valve implantation (TAVI) candidates. However, the backgrounds of TAVI candidates and comorbidities differ based on the race and/or country, and data on IFs in a specific population are not always applicable to another. The aim of this study was to assess the prevalence, type, and clinical impact of IFs in Japanese TAVI candidates. This was a retrospective, single-center, observational study. CT reports of 257 TAVI candidates were reviewed, and IFs were classified as (a) insignificant: findings that did not require further investigation, treatment, or follow-up; (b) intermediate: findings that needed to be followed up or were considered for further investigation but did not affect the planning of TAVI; and (c) significant: findings that required further investigation immediately or affected the planning of TAVI. At least one IF was found in 254 patients (98.8%). Insignificant, intermediate, and significant IFs were found in 253 (98.4%), 153 (59.5%), and 34 (13.2%) patients, respectively. Newly indicated significant IFs were found in 19 patients (7.4%). In 2 patients (0.8%), TAVI was canceled because of significant IFs. In patients who consequently underwent TAVI, the presence of significant IFs was not associated with the duration from CT performance to TAVI [28 (19-40) days vs. 27 (19-43) days, p = 0.74] and all-cause mortality during the median follow-up period of 413 (223-805) days (p = 0.44). Almost all Japanese TAVI candidates had at least one IF, and the prevalence of significant IFs was not negligible. Although the presence of significant IFs was not associated with mid-term mortality, appropriate management of IFs was considered important.

DOI： 10.1007/s00380-021-01875-2

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1136/bmjopen-2021-054885

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.ejmp.2021.10.017

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A 59-year-old man with jaundice and lower common bile duct stenosis was referred to our institution for diagnosis and treatment. Computed tomography and magnetic resonance imaging showed a well-circumscribed smoothly marginated solid mass lesion in the pancreatic head. He underwent pyloric preserving pancreatoduodenectomy. Histopathological specimen revealed that the mass was located in the dilated branch duct of the pancreatic head, and an intraductal tubulopapillary neoplasm originating from the branch pancreatic duct was diagnosed. On magnetic resonance cholangiopancreatography, the mass within the dilated duct branch in the pancreatic head was similar to a "cast in the mold" image, which we retrospectively deemed, might be reflecting the nature of this tumor.

DOI： 10.18999/nagjms.83.4.869

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The thalamus is critical for the brain's integrative hub functions; however, the localization and characterization of the different thalamic hubs remain unclear. Using a voxel-level network measure called functional connectivity overlap ratio (FCOR), we examined the thalamus' association with large-scale resting-state networks (RSNs) to elucidate its connector hub roles. Connections to the core-neurocognitive networks were localized in the anterior and medial parts, such as the anteroventral and mediodorsal nuclei areas. Regions functionally connected to the sensorimotor network were distinctively located around the lateral pulvinar nucleus but to a limited extent. Prominent connector hubs include the anteroventral, ventral lateral, and mediodorsal nuclei with functional connections to multiple RSNs. These findings suggest that the thalamus, with extensive connections to most of the RSNs, is well placed as a critical integrative functional hub and could play an important role for functional integration facilitating brain functions associated with primary processing and higher cognition.

DOI： 10.1016/j.isci.2021.103106

Web of Science

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

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


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


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


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



</sec>

DOI： 10.1007/s11604-021-01137-1

Web of Science

PubMed

その他リンク： https://link.springer.com/article/10.1007/s11604-021-01137-1/fulltext.html

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Autoimmune pancreatitis (AIP) is a pancreatic phenotype of IgG4-related systemic disease. Since its first description in the literature, characteristic imaging features have gradually become known to many clinicians encompassing various specialties in the past quarter century. CT and MRI have been the workhorses for imaging diagnosis of AIP. Typical features include sausage-like swelling of the focal or entire pancreas, duct-penetrating sign, a capsule-like rim of the affected lesions, and homogeneous delayed enhancement or enhanced duct sign after contrast administration, as well as characteristic combined findings reflecting coexisting pathologies in the other organs as a systemic disease. In this review, recent and future developments in CT and MRI that may help diagnose AIP are discussed, including restricted diffusion and perfusion and increased elasticity measured using MR.

DOI： 10.1007/s10396-021-01145-8

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Standard treatments for small cell carcinoma of the cervix (SCCC) have not been established. In this study, we aimed to estimate the optimal treatment strategy for SCCC. METHODS: This was a multicenter retrospective study. Medical records of patients with pathologically proven SCCC treated between 2003 and 2016 were retrospectively analyzed. Overall survival (OS) was plotted using the Kaplan-Meier method. Log-rank tests and Cox regression analysis were used to assess the differences in survival according to stage, treatment strategy, and chemotherapy regimen. RESULTS: Data of 78 patients were collected, and after excluding patients without immunohistopathological staining, 65 patients were evaluated. The median age of the included patients was 47 (range: 24-83) years. The numbers of patients with International Federation of Gynecology and Obstetrics (FIGO) 2018 stages I-IIA, IIB-IVA, IVB were 23 (35%), 34 (52%), and 8 (12%), respectively. Of 53 patients who had undergone chemotherapy, 35 and 18 received SCCC and non-SCCC regimens as their first-line chemotherapy regimen, respectively. The 5-year OS for all patients was 49%, while for patients with FIGO stages I-IIA, IIB-IVA, IVB, it was 60, 50, and 0%, respectively. The 5-year OS rates for patients who underwent treatment with SCCC versus non-SCCC regimens were 59 and 13% (p < 0.01), respectively. This trend was pronounced in locally advanced stages. Multivariate analysis showed that FIGO IVB at initial diagnosis was a significant prognostic factor in all patients. Among the 53 patients who received chemotherapy, the SCCC regimen was associated with significantly better 5-year OS in both the uni- and multivariate analyses. CONCLUSION: Our results suggest that the application of an SCCC regimen such as EP or IP as first-line chemotherapy for patients with locally advanced SCCC may play a key role in OS. These findings need to be validated in future nationwide, prospective clinical studies.

DOI： 10.1186/s12885-021-08772-x

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2176/nmc.oa.2021-0058

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Otological diseases including Meniere's disease (MD) involve endolymphatic hydrops (EH), which can be visualized by magnetic resonance imaging (MRI) with gadolinium contrast agents, but the temporal changes of contrast in the inner ear have not been evaluated. OBJECTIVES: We investigated the permeability of the blood-perilymph barrier (BPB) in ears with EH to evaluate the severity of the inner ear disturbances. MATERIALS AND METHODS: The study included 32 ears from 16 patients with EH or related diseases who underwent MRI. The permeability of the BPB was assessed by the signal-intensity ratio (SIR) at four-time points: before and at 10 min, 4 h, and 24 h after administration of gadolinium for assessing EH. RESULTS: Cochlear EH was found in 25 of the 32 ears, and vestibular EH in 11. The rate of EH was significantly higher in symptomatic ears; however, the existence of EH was not related to SIR values. Nevertheless, SIR values in the basal turn were significantly higher 4 and 24 h after injection of gadolinium in patients aged ≥50 years. CONCLUSION AND SIGNIFICANCE: Higher SIR values observed in older patients with EH indicate severe disturbances of the BPB in the cochlea, which may account for intractable inner ear disturbances in older patients.

DOI： 10.1080/00016489.2021.1957500

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVES: To investigate the clinical features of ears with dilatation of the endolymphatic space in the ampulla of the posterior semicircular canal on magnetic resonance imaging. STUDY DESIGN: Retrospective study. SETTING: A university hospital. METHODS: This study included 1,842 ears from 934 patients who underwent 3-T magnetic resonance imaging with gadolinium to investigate the presence of endolymphatic hydrops. Age, sex distribution, hearing thresholds on pure-tone audiometry, and vestibular symptoms were compared between cases of unilateral and bilateral dilatation of the endolymphatic space in the ampulla of the posterior semicircular canal. RESULTS: Forty-eight ears (17 men and 14 women; mean age 49.9 yrs) showed dilatation of the endolymphatic space in the ampulla of the posterior semicircular canal. Age and the rate of chronic sensorineural hearing loss were significantly higher in the unilateral group (14 ears) than in the bilateral group (34 ears). The average hearing thresholds and rates of vestibular symptoms reported did not differ between unilateral and bilateral cases, but some patients showed positional nystagmus. CONCLUSIONS: Dilatation of the endolymphatic space in the ampulla was observed selectively in the posterior semicircular canal, though its pathogenesis was not clear. Such dilatation is not usually accompanied by vestibular endolymphatic hydrops, and it may be a cause of vertigo and dizziness.

DOI： 10.1097/MAO.0000000000003073

Web of Science

PubMed

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：医用画像情報学会  

COVID-19が世界中に広まり、COVID-19肺炎の診断に胸部CTや胸部単純X線の有用性が報告され、この画像所見を用いたAI開発が初期の段階から積極的に行われた。高性能なAIが多数存在するが、臨床において用いる際には注意すべき点が複数存在する。COVID-19肺炎に対して開発・使用された画像診断に関連するAI研究について、PubMedに2020年12月までに登録されたものを抽出しレビューを行った。

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

Background: Pathologically, Meniere's disease symptoms are considered to be associated with endolymphatic hydrops. Examinations revealing endolymphatic hydrops can be useful for accurate Meniere's disease diagnosis. We previously reported a quantitative method for evaluating endolymphatic hydrops, i.e., by measuring the volume of the endolymphatic space using three-dimensional magnetic resonance imaging (MRI) of the inner ear. This study aimed to confirm the usefulness of our methods for diagnosing Meniere's disease. Here, we extracted new explanatory factors for diagnosing Meniere's disease by comparing the volume of the endolymphatic space between healthy volunteers and patients with Meniere's disease. Additionally, we validated our method by comparing its diagnostic accuracy with that of the conventional method.

Methods and Findings: This is a prospective diagnostic accuracy study performed at vertigo/dizziness centre of our university hospital, a tertiary hospital. Eighty-six patients with definite unilateral Meniere's disease and 47 healthy volunteers (25 and 33 males, and 22 and 53 females in the control and patient groups, respectively) were enrolled. All participants underwent 3-Tesla MRI 4 h after intravenous injection of gadolinium to reveal the endolymphatic space. The volume of the endolymphatic space was measured and a model for Meniere's disease diagnosis was constructed and compared with models using conventional criteria to confirm the effectiveness of the methods used. The area under the receiver operating characteristic curve of the method proposed in this study was excellent (0.924), and significantly higher than that derived using the conventional criteria (0.877). The four indices, sensitivity, specificity, positive predictive value, and negative predictive value, were given at the threshold; all of these indices achieved higher scores for the 3D model compared to the 2D model. Cross-validation of the models revealed that the improvement was due to the incorporation of the semi-circular canals.

Conclusions: Our method showed high diagnostic accuracy for Meniere's disease. Additionally, we revealed the importance of observing the semi-circular canals for Meniere's disease diagnosis. The proposed method can contribute toward providing effective symptomatic relief in Meniere's disease.

DOI： 10.3389/fsurg.2021.671624

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The accuracy of brain age estimates from magnetic resonance (MR) images has improved with the advent of deep learning artificial intelligence (AI) models. However, most previous studies on predicting age emphasized aging from childhood to adulthood and old age, and few studies have focused on early brain development in children younger than 2 years of age. Here, we performed brain age estimates based on MR images in children younger than 2 years of age using deep learning. Our AI model, developed with one slice each of raw T1- and T2-weighted images from each subject, estimated brain age with a mean absolute error of 8.2 weeks (1.9 months). The estimates of our AI model were close to those of human specialists. The AI model also estimated the brain age of subjects with a myelination delay as significantly younger than the chronological age. These results indicate that the prediction accuracy of our AI model approached that of human specialists and that our simple method requiring less data and preprocessing facilitates a radiological assessment of brain development, such as monitoring maturational changes in myelination.

DOI： 10.1016/j.mri.2021.03.004

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCI LTD  

Purpose: Equipment refurbishment was performed to remove the beam-hardening filter (BHF) from the CyberKnife system (CK). This study aimed to confirm the change in the beam characteristics between the conventional CK (present-BHF CK) and CK after the BHF was removed (absent-BHF CK) and evaluate the impact of BHF removal on the beam quality correction factors kQ. Methods: The experimental measurements of the beam characteristics of the present- and absent-BHF CKs were compared. The CKs were modeled using Monte Carlo simulations (MCs). The energy fluence spectra were calculated using MCs. Finally, kQ were estimated by combining the MC results and analytic calculations based on the TRS-398 and TRS-483 approaches. Results: All gamma values for percent depth doses and beam profiles between each CK were less than 0.5 following the 3%/1 mm criteria. The percentage differences for tissue-phantom ratios at depths of 20 and 10 cm and percentage depth doses at 10 cm between each CK were -1.20% and -0.97%, respectively. The MC results demonstrated that the photon energy fluence spectrum of the absent-BHF CK was softer than that of the presentBHF CK. The kQ values for the absent-BHF CK were in agreement within 0.02% with those for the present-BHF CK. Conclusions: The photon energy fluence spectrum was softened by the removal of BHF. However, no remarkable impact was observed for the measured beam characteristics and kQ. Therefore, the previous findings of the kQ values for the present-BHF CK can be directly used for the absent-BHF CK.

DOI： 10.1016/j.ejmp.2021.05.011

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PubMed

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

Purpose: The purpose of this retrospective study was to investigate the relationship between age and leakage of intravenously administered gadolinium-based contrast agents (GBCAs) into the cerebrospinal fluid (CSF) by volumetric segmentation of the whole-cranium CSF. Materials and methods: In 30 patients clinically diagnosed with suspected endolymphatic hydrops, the three-dimensional real inversion recovery (3D-real IR) images were obtained at pre- and 4 h post-intravenous administration of a single dose of GBCA. The volume of interest was set on the whole-cranium CSF in the 3D-real IR image. The signal intensity (SI)-increase of the ventricular CSF and the extra-ventricular CSF at 4 h post-administration of GBCA compared to pre-administration was measured. The relationship between the age of the patient and the SI-increase was evaluated. Results: A correlation between age and the SI-increase was observed in the whole-cranium CSF. The correlation coefficient between age and the SI-increase in the ventricular CSF was higher than that in the extra-ventricular CSF. Conclusion: An age-related leakage of the intravenously administered GBCAs was found in the whole-brain CSF. The age-related change in the distribution of the GBCA leakage was more prominent in the ventricular CSF than in the extra-ventricular CSF.

DOI： 10.1007/s11604-020-01079-0

Web of Science

Scopus

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nagoya University  

Glottic carcinoma is the most common laryngeal cancer. The outcomes for T1 bulky Glottic carcinoma and T2N0 Glottic carcinoma after radiation therapy alone are unsatisfactory. This study was conducted to evaluate the efficacy and safety of unique concurrent chemoradiotherapy regimen using S-1 for early glottic cancer. Concurrent chemoradiotherapy consisted of 60 Gy in 30 fractions with once-daily, orally administered S-1 exclusively within three to six hours prior to each irradiation. Twenty-one consecutive patients treated with this regimen were retrospectively reviewed. Initial complete remission was achieved in all patients without any subsequent local and/or regional recurrences to the last follow-up. The 4-year local control, overall survival, and disease-free survival rates were all 100%. No significant toxicities were observed, except for three cases with Grade 3 acute dermatitis. This regimen is highly effective and well-tolerated, and these results encourage further research to long-term efficacy and functional preservation.

DOI： 10.18999/nagjms.83.2.251

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Scopus

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

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



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


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


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


</sec>

DOI： 10.1007/s11604-020-01075-4

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PubMed

その他リンク： http://link.springer.com/article/10.1007/s11604-020-01075-4/fulltext.html

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：John Wiley and Sons Ltd  

Purpose: This study examined the variation in the thyroid volume determined by the ellipsoid approximation method due to differences in the measured length or area of the cross-sectional plane of CT images. Methods: Forty-five patients with Graves' disease were included in this retrospective study. We designated the three-dimensional thyroid volumes extracted manually (VCT) as the reference data and calculated five approximate volumes for comparison: (a) the mean volume of 8100 different thyroid volumes depending on the diameter of the cross-sectional plane at the midpoint of the major axis, (Vellipsoid,mean)
(b) the volume using the maximum diameter and its orthogonal diameter, (Vellipsoid,maxlength)
(c) the maximum (Vellipsoid,maxvolume)
(d) minimum (Vellipsoid,minvolume) of the 8100 thyroid volumes
and (e) the volume determined with an equivalent circle diameter, (Vellipsoid,Heywood). Results: Thyroid volumes obtained via the ellipsoid approximation method varied depending on the diameter of the cross-sectional plane and included a mean error of approximately 20%, while the concordance correlation coefficient (CCC) differed for each approximate volume. Among these volumes, Vellipsoid,mean and Vellipsoid,Heywood were in good agreement with VCT, according to single regression analyses and the resultant CCC values, with mean errors of 0.1% and 10.4%, respectively. Conclusion: While Vellipsoid,Heywood approximated thyroid volumes with vastly reduced errors, we recommend utilizing three-dimensional thyroid volumetry if measurement accuracy is required.

DOI： 10.1002/acm2.13125

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Scopus

PubMed

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(株)インナービジョン  

MRIは、周辺技術の進歩により高画質、高速化が進められ、画像診断において重要な位置を占めている。MRによる生体内情報として、各組織のプロトンの密度、T1緩和、T2緩和、磁化率、拡散、血流、体液の流れ、灌流情報などの画像化、代謝情報が得られるが、その中で、血流や体液の流速を計測する試みは、位相コントラスト法を用いて古くから行われてきた。本稿では、血管領域に関する機能画像として、研究段階ではあるが、三次元の空間に時間軸情報を加えた三次元シネ位相コントラスト(phase contrast:PC)法である「4D flow MRI」について、主として大血管における現状を紹介する。(著者抄録)

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Diagnosis and severity assessments of portosystemic shunts (PSSs) are important because the pathology sometimes results in severe hepatic encephalopathy, which can be treated almost completely by shunt embolization. At present, morphological assessment of PSS is performed mainly by computed tomography, and ultrasound is used for blood flow assessment. In two cases of PSS-related hepatic encephalopathy, we used time-resolved 3D cine phase-contrast (4D-flow) magnetic resonance imaging (MRI) to assess blood flow before and after shunt embolization. Before the intervention, blood flow in the main trunk of the superior mesenteric vein was mostly hepatofugal. However, post-interventional 4D-flow MRI revealed hepatopetal superior mesenteric vein flow with significantly increased portal vein blood flow. 4D-flow MRI is an ideal adjunct to Doppler ultrasonography, allowing for objective and visual assessment of morphology and blood flow of the portal venous system, including PSSs, and is useful in determining the indications for, and outcome of, PSS embolization.

DOI： 10.1111/hepr.13616

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：日本語  

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本放射線技術学会  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Meniere's disease (MD) characteristically presents with endolymphatic hydrops (EH), which can be visualized with gadolinium-enhanced inner ear magnetic resonance imaging (MRI). Inner ear membrane rupture has been suspected to cause MD attacks, but this remains controversial. We report a case of MD coincidentally evaluated the EH using 3-Tesla MRI during a vertigo attack. A 78-year-old man with bilateral definite MD visited the hospital outpatient department due to a vertigo attack. To evaluate of endolymphatic hydrops on the attack, inner ear MRI was obtained 4 hours after intravenous injection of gadolinium agent. Vestibular EH in each ear occupied almost all vestibular endolymphatic space in contact with the oval window and herniated into the horizontal semi-circular canal. The endolymphatic space was enlarged, without collapse or mixture of contrast agent. No difference was found between ears. EH on a vertigo attack was associated with significant swelling, without obvious evidence of membranous ruptures on magnetic resonance images.

DOI： 10.18999/nagjms.83.1.209

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PubMed

担当区分：最終著者   記述言語：日本語  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: To investigate the correlation between iodine-related attenuation in contrast-enhanced dual-energy computed tomography (DE-CT) and the postoperative prognosis of surgically resected solid-type small-sized lung cancers. METHODS: We retrospectively reviewed the DE-CT findings and postoperative course of solid-type lung cancers ≤3 cm in diameter. After injection of iodinated contrast media, arterial phases were scanned using 140-kVp and 80-kVp tube voltages. Three-dimensional iodine-related attenuation (3D-IRA) of primary tumors at the arterial phase was computed using the "lung nodule" application software. The corrected 3D-IRA normalized to the patient's body weight and contrast medium concentration was then calculated. RESULTS: A total of 120 resected solid-type lung cancers ≤3 cm in diameter were selected for analysis (82 males and 38 females; mean age, 67 years). During the observation period (median, 47 months), 32 patients showed postoperative recurrence. Recurrent tumors had significantly lower 3D-IRA and corrected 3D-IRA at early phase compared to non-recurrent tumors (p = 0.046 and p = 0.027, respectively). The area under the receiver operating characteristic curve for postoperative recurrence was 0.624 for the corrected 3D-IRA at early phase (p = 0.025), and the cutoff value was 5.88. Kaplan-Meier curves for disease-free survival indicated that patients showing tumors with 3D-IRA > 5.88 had a significantly better prognosis than those with tumors showing 3D-IRA < 5.88 (p = 0.017). CONCLUSIONS: The 3D-IRA of small-sized solid-type lung cancers on contrast-enhanced DE-CT was significantly associated with postoperative prognosis, and low 3D-IRA tumors showed a higher TNM stage and a significantly poorer prognosis.

DOI： 10.1186/s40644-020-00368-1

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: High signals in the inner ear of idiopathic sudden sensorineural hearing loss (ISSNHL) on magnetic resonance imaging (MRI) have been reported, but no quantitative evaluation has yet been done. OBJECTIVES: To evaluate hearing outcomes and cochlear signal intensities on 3-T heavily T2-weighted three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (hT2W-3D-FLAIR) in patients with ISSNHL. MATERIALS AND METHODS: Twenty-nine patients with ISSNHL were included. Patients underwent hT2W-3D-FLAIR with intravenous gadolinium injection and pure tone audiometry (PTA) at initial visits and 3 months later. Signal intensity ratios (SIRs) were measured in the basal or apical-middle turns of the affected cochlea. A statistical analysis of relationships between SIRs and the average hearing levels (HLs) at low (125, 250, and 500 Hz) and high (2, 4, and 8 kHz) tone frequencies was performed. RESULTS: Hearing improvements at high-tone frequencies in ears with HLs ≥60 dB were significantly worse in those with high SIRs at the basal turns on pre-contrast images. Similarly, hearing improvements at low-tone frequencies in ears with HLs ≥60 dB were significantly worse in those with high SIRs at the apical-middle turns on post-contrast images. CONCLUSIONS AND SIGNIFICANCE: High SIRs on hT2W-3D-FLAIR indicate cochlear disturbances with severe ISSNHL and could provide lesion-specific prognostic information.

DOI： 10.1080/00016489.2020.1827159

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1007/s11604-020-01017-0

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Society for Magnetic Resonance in Medicine  

Purpose: Leakage of a small amount of intravenously administered gadolinium-based contrast agents (GBCAs) into the cerebrospinal fluid (CSF) space has been reported, even in healthy subjects without blood-brain barrier disruption. Several candidates including the choroid plexus and cortical veins have been proposed as the source of the leakage. The purpose of this study was to evaluate the distribution of intravenously administered GBCA leakage into the CSF by comparing the contrast enhancement of the cerebral cisterns to the lateral ventricles (LVs). Methods: In 26 patients with a suspicion of endolymphatic hydrops (21-80 years old), a three-dimensional real inversion recovery (3D-real IR) image was obtained at pre-, and at 5 min, and 4 h post-intravenous administration of a single dose of GBCA (IV-SD-GBCA). In the 3D-real IR image, the signal intensities (SIs) in the anterior horn of the LV (LVante), the trigone of the LV (LVtri), the Sylvian fissure (SyF), the ambient cistern (Amb), the prepontine cistern (PPC), the cerebellopontine angle cistern (CPA), and the vitreous (Vit) were measured. The differences in the SI at pre-, and at 5 min and 4 h post-IV-SD-GBCA were evaluated for each region. The change in the SI pre- to post-IV-SD-GBCA (SIchange) were calculated for each region. The differences in the SIchange in each region were evaluated at 5 min and 4 h post-IV-SD-GBCA. A Steel-Dwass’s test was applied to correct for multiple comparisons. Results: The SIs of all regions at 4 h post-IV-SD-GBCA were significantly higher compared with pre-IV-SD-GBCA (P &lt
0.05). The SIchange in the SyF, Amb, PPC, and the CPA were significantly higher compared with those of the LVante, LVtri, and the Vit at 4 h post-IV-SD-GBCA (P &lt
0.05). Conclusion: The contrast enhancement in the cerebral cisterns was greater than that in the LVs.

DOI： 10.2463/mrms.mp.2020-0016

Web of Science

Scopus

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Non-calcified cholesterol stones that are small in size are hard to be depicted on CT or magnetic resonance cholangiopancreatography. This institutional review board (IRB)-approved retrospective in vitro study aims to characterize contrast behaviors of 3 main components of the gallstones, i.e., cholesterol component (CC), bilirubin calcium component (BC) and CaCO3 (CO) on 3D radial scan with ultrashort TE (UTE) MRI, and to test the capability of depicting CC of gallstones as bright signals as compared to background saline. METHODS: Fourteen representative gallstones from 14 patients, including 15 CC, 6 BC and 4 CO, were enrolled. The gallstones underwent MRI including fat-saturated T1-weighted image (fs-T1WI) and UTE MRI with dual echoes. The contrast-to-noise ratio (CNR) and the chemical analysis for the 25 portions of the stones were compared. RESULTS: BC was bright on fs-T1WI, which did not change dramatically on UTE MRI and the signal did not remain on UTE subtraction image between dual echoes. Whereas the CC was negative or faintly positive signal on fs-T1WI, bright signal on UTE MRI and the contrast remained even higher on the UTE subtraction, which reflected their short T2 values. Median CNRs and standard errors of the segments on each imaging were as follows: on fs-T1WI, -10.2 ± 4.2 for CC, 149.7 ± 27.6 for BC and 37.9 ± 14.3 for CO; on UTE MRI first echo, 16.7 ± 3.3 for CC, 74.9 ± 21.3 for BC and 17.7 ± 8.4 for CO; on UTE subtraction image, 30.2 ±2.0 for CC, -11.2 ± 5.4 for BC and 17.8 ± 10.7 for CO. Linear correlations between CNRs and cholesterol concentrations were observed on fs-T1WI with r = -0.885, (P < 0.0001), UTE MRI first echo r = -0.524 (P = 0.0072) and UTE subtraction with r = 0.598 (P = 0.0016). CONCLUSION: UTE MRI and UTE subtraction can depict CC bright.

DOI： 10.2463/mrms.mp.2020-0009

Web of Science

PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2020-0138

Web of Science

PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2020-0062

Web of Science

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

We present a case of a patient who underwent portal vein (PV) stenting for PV stenosis after a living-donor liver transplantation. A pretreatment 3D cine phase-contrast (4D-flow) MRI showed decreased, though hepatopetal, blood flow in the PV. After stenting, 4D-flow MRI confirmed an improvement in PV flow, with a more homogeneous flow distribution to each hepatic segment. 4D-flow MRI are valuable for understanding the hemodynamics of this area, planning for treatments, and evaluating the outcome of the interventions.

DOI： 10.2463/mrms.ici.2020-0057

Web of Science

PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: MRI of endolymphatic hydrops (EH) 4 h after intravenous administration of a single dose of gadolinium-based contrast agent is used for clinical examination in some institutions; however, further improvement in image quality would be valuable for wider clinical utility. Denoising using deep learning reconstruction (Advanced Intelligent Clear-IQ Engine [AiCE]) has been reported for CT and MR. The purpose of this study was to compare the contrast-to-noise ratio of endolymph to perilymph (CNREP) between the improved hybrid of reversed image of the positive endolymph signal and the native image of the perilymph signal multiplied with the heavily T2-weighted MR cisternography (iHYDROPS-Mi2) images, which used AiCE for the three source images (i.e. positive endolymph image [PEI], positive perilymph image [PPI], MR cisternography [MRC]) to those that did not use AiCE. We also examined if there was a difference between iHYDROPS-Mi2 images with and without AiCE for degree of visual grading of EH and in endolymphatic area [EL] ratios. METHODS: Nine patients with suspicion of EH were imaged on a 3T MR scanner. iHYDROPS images were generated by subtraction of PEI images from PPI images. iHYDROPS-Mi2 images were then generated by multiplying MRC with iHYDROPS images. The CNREP and EL ratio were measured on the iHYDROPS-Mi2 images. Degree of radiologist visual grading for EH was evaluated. RESULTS: Mean CNREP ± standard deviation was 1681.8 ± 845.2 without AiCE and 7738.6 ± 5149.2 with AiCE (P = 0.00002). There was no significant difference in EL ratio for images with and without AiCE. Radiologist grading for EH agreed completely between the 2 image types in both the cochlea and vestibule. CONCLUSION: The CNREP of iHYDROPS-Mi2 images with AiCE had more than a fourfold increase compared with that without AiCE. Use of AiCE did not adversely affect radiologist grading of EH.

DOI： 10.2463/mrms.mp.2020-0082

Web of Science

PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2020-0030

Web of Science

PubMed

担当区分：筆頭著者,　責任著者   記述言語：日本語  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.radcr.2020.10.021

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

The aim of this study was to conduct a flow experiment using a cerebrovascular phantom and investigate whether magnetic resonance angiography (MRA) could replace three-dimensional rotational angiography (RA) and computed tomography angiography (CTA) to construct vascular models for computational fluid dynamics (CFD). We performed MRA and 3D cine phase-contrast (PC) MR imaging with a silicone cerebrovascular phantom of an internal carotid artery-posterior communicating artery aneurysm with blood-mimicking fluid, and controlled flow with a flowmeter. We also obtained RA and CTA data for the phantom. Four analysts constructed vascular models based on the three different modalities. These 12 constructed models used flow information based on 3D cine PC MR imaging for CFD. We compared RA-, CTA-, MRA-based CFD results using the micro-CT-based CFD result as the criterion standard to investigate whether MRA-based CFD was not inferior to RA- or CTA-based CFD. We also analyzed the inter-analyst variability. Wall shear stress (WSS) distributions and streamlines of RA- or MRA-based CFD and those of micro-CT-based CFD were similar, but the vascular models and WSS values were different. Accuracy in measurements of blood vessel diameter, cross-sectional maximum velocity, and spatially averaged WSS was the highest for RA-based CFD, followed by MRA-based and CTA-based CFD using micro-CT-based CFD result as the reference. Except maximum velocity from CTA, all other parameters had good inter-analyst agreement using different modalities. The results demonstrated that non-invasive MRA can be used for cerebrovascular CFD models with good inter-analyst agreements.

DOI： 10.1007/s13246-020-00936-6

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：日本語  

担当区分：最終著者   記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Neuroimaging studies have shown that the brain is functionally organized into several large-scale brain networks. Within these networks are regions that are widely connected to several other regions within and/or outside the network. Regions that connect to several other networks, known as connector hubs, are believed to be crucial for information transfer and between-network communication within the brain. To identify regions with high between-network connectivity at the voxel level, we introduced a novel metric called functional connectivity overlap ratio (FCOR), which quantifies the spatial extent of a region's connection to a given network. Using resting state functional magnetic resonance imaging data, FCOR maps were generated for several well-known large-scale resting state networks (RSNs) and used to examine the relevant associations among different RSNs, identify connector hub regions in the cerebral cortex, and elucidate the hierarchical functional organization of the brain. Constructed FCOR maps revealed a strong association among the core neurocognitive networks (default mode, salience, and executive control) as well as among primary processing networks (sensorimotor, auditory, and visual). Prominent connector hubs were identified in the bilateral middle frontal gyrus, posterior cingulate, lateral parietal, middle temporal, dorsal anterior cingulate, and anterior insula, among others, regions mostly associated with the core neurocognitive networks. Finally, clustering the whole brain using FCOR features yielded a topological organization that arranges brain regions into a hierarchy of information processing systems with the primary processing systems at one end and the heteromodal systems comprising connector hubs at the other end.

DOI： 10.1016/j.neuroimage.2020.117241

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.3348/kjr.2020.0042

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

Recent studies have demonstrated that connector hubs, regions considered critical for the flow of information across neural systems, are mostly involved in neurodegenerative dementia. Considering that aging can significantly affect the brain's intrinsic connectivity, identifying aging's impact on these regions' overall connection strength is important to differentiate changes associated with healthy aging from neurodegenerative disorders. Using resting state functional magnetic resonance imaging data from a carefully selected cohort of 175 healthy volunteers aging from 21 to 86 years old, we computed an intrinsic connectivity contrast (ICC) metric, which quantifies a region's overall connectivity strength, for whole brain, short-range, and long-range connections and examined age-related changes of this metric over the adult lifespan. We have identified a limited number of hub regions with ICC values that showed significant negative relationship with age. These include the medial precentral/midcingulate gyri and insula with both their short-range and long-range (and thus whole-brain) ICC values negatively associated with age, and the angular, middle frontal, and posterior cingulate gyri with their long-range ICC values mainly involved. Seed-based connectivity analyses further confirmed that these regions are connector hubs with connectivity profile that strongly overlapped with multiple large-scale brain networks. General cognitive performance was not associated with these hubs' ICC values. These findings suggest that even healthy aging could negatively impact the efficiency of regions critical for facilitating information transfer among different functional brain networks. The extent of the regions involved, however, was limited.

DOI： 10.3389/fnagi.2020.592469

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: High signal intensity in the endolymphatic duct (ED) is occasionally observed on magnetic resonance imaging (MRI) in ears that have otological disorders. OBJECTIVE: The signal intensity (SI) in the ED on post-contrast MRI was investigated in subjects with various otological disorders, and the meaning of high SI in the ED was evaluated. MATERIAL AND METHODS: 392 patients with otological disorders and 21 controls without otological symptoms underwent 3 T MRI. The SIs of the ED and the cerebellum were measured, the SI ratio (SIR) was calculated, and ears with SIR ≥4 were identified. RESULTS: A high SIR was identified in the ED of 3.7% of ears affected by definite Meniere's disease (dMD), 100% of ears affected by large vestibular aqueduct syndrome (LVAS), and 7.1% of ears with no otological symptoms. On the whole, a significant relationship was found between the existence of vestibular or cochlear EH and the SIR in the ED. CONCLUSION: The MRI finding of high SI in the ED may indicate the mechanism of inner ear disturbances in ears with otological disorders, especially in those with LVAS, and it may suggest an underlying disorder in some ears in which otological symptoms are not apparent.

DOI： 10.1080/00016489.2020.1781927

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1016/j.pediatrneurol.2020.06.008

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

The results of research on the use of artificial intelligence (AI) for medical imaging of the lungs of patients with coronavirus disease 2019 (COVID-19) has been published in various forms. In this study, we reviewed the AI for diagnostic imaging of COVID-19 pneumonia. PubMed, arXiv, medRxiv, and Google scholar were used to search for AI studies. There were 15 studies of COVID-19 that used AI for medical imaging. Of these, 11 studies used AI for computed tomography (CT) and 4 used AI for chest radiography. Eight studies presented independent test data, 5 used disclosed data, and 4 disclosed the AI source codes. The number of datasets ranged from 106 to 5941, with sensitivities ranging from 0.67-1.00 and specificities ranging from 0.81-1.00 for prediction of COVID-19 pneumonia. Four studies with independent test datasets showed a breakdown of the data ratio and reported prediction of COVID-19 pneumonia with sensitivity, specificity, and area under the curve (AUC). These 4 studies showed very high sensitivity, specificity, and AUC, in the range of 0.9-0.98, 0.91-0.96, and 0.96-0.99, respectively.

DOI： 10.5152/dir.2019.20294

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1002/hbm.25008

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: The purpose of this study was to evaluate accelerated fractionated radiotherapy (AFRT) without elective nodal irradiation (ENI) for T3N0 glottic cancer (GC) without vocal cord fixation, especially in comparison with chemoradiotherapy (CRT) and hyperfractionated radiotherapy (HFRT) both of which included ENI. METHODS: The medical charts of patients with T3N0GC without cord fixation received definitive radiotherapy between June 2005 and March 2018 were reviewed. RESULTS: A total of 74 patients were analyzed. After a median follow-up time of 46 months (range, 12-141), 3-year local failure in AFRT/CRT/HFRT (n = 41/10/23) was 10%/20%/26%, 3-year regional failure 6%/0%/9%, 3-year progression-free survival 71%/69%/74%, and 3-year overall survival 77%/100%/87%. There were no significant differences among three groups in recurrence or survival. Grade 3 adverse events (AEs) were noted in 5/2/8 patients (12%/20%/35%) in AFRT/CRT/HFRT, respectively. There were no Grade 4/5 AEs. CONCLUSIONS: AFRT without ENI is an effective and feasible treatment for T3N0GC without cord fixation.

DOI： 10.1002/hed.26092

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PubMed

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(一社)日本インターベンショナルラジオロジー学会  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background: The presence of endolymphatic hydrops (EH) may cause hearing loss and affect the transmission of acoustic energy to the inner ear.Objectives: Acoustic energy absorbance on wideband acoustic immittance (WAI) was evaluated, focusing especially on EH in the vestibule.Material and methods: A total of 32 ears from 16 patients who underwent 3-T magnetic resonance imaging (MRI) to evaluate the presence of EH were examined, retrospectively. The degree of EH in the vestibule was classified into three grades (no, mild, and significant), and pure tone audiometry (PTA) and WAI were measured before and after a glycerol drip.Results: Ears with significant EH showed significantly higher hearing levels and air-bone gaps (ABG), and higher absorbance values on WAI at low frequencies (560-600 Hz) than ears with mild or no EH. Changes in absorbance values were observed in some ears without threshold change on PTA.Conclusions and Significance: This study showed significantly higher absorbance values of acoustic energy with significant vestibular EH at low frequencies. Considering ABGs observed in ears with significant EH, the presence of EH in the vestibule might cause an obstacle to the transmission of acoustic energy to the inner ear.

DOI： 10.1080/00016489.2020.1754460

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Although phase III trials have been published comparing whole breast irradiation (WBI) with accelerated partial breast irradiation (APBI) using intraoperative radiotherapy (IORT), long-term follow-up results are lacking. We report the 10-year follow-up results of a prospective phase I/II clinical trial of IORT. The inclusion criteria were as follows: (i) tumor size <2.5 cm, (ii) desire for breast-conserving surgery, (iii) age >50 years, (iv) negative margins after resection and (v) sentinel lymph node-negative disease. A single dose of IORT (19-21 Gy) was delivered to the tumor bed in the operation room just after wide local excision of the primary breast cancer using a 6-12 MeV electron beam. Local recurrence was defined as recurrence or new disease within the treated breast and was evaluated annually using mammography and ultrasonography. A total of 32 patients were eligible for evaluation. The median patient age was 65 years and the median follow-up time was 10 years. Two patients experienced local recurrence just under the nipple, out of the irradiated field, after 8 years of follow-up. Three patients had contralateral breast cancer and one patient experienced bone metastasis after 10 years of follow-up. No patient experienced in-field recurrence nor breast cancer death. Eight patients had hypertrophic scarring at the last follow-up. There were no lung or heart adverse effects. This is the first report of 10-year follow-up results of IORT as APBI. The findings suggest that breast cancer with extended intraductal components should be treated with great caution.

DOI： 10.1093/jrr/rraa029

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Adding segment 4 (S4) portal vein embolization (PVE) to right PVE before right hepatic trisectionectomy is controversial. We retrospectively examined the effect of S4 PVE on segments 2 and 3 (S2+3) hypertrophy. METHODS: We reviewed patients with biliary carcinoma who underwent right PVE with (R3PVE) or without (R2PVE) S4 PVE using gelatin sponge particles and coils (2010-2019). Propensity score matching balanced the cohort for baseline characteristics, including total liver volume and S2+3 volume before PVE. We compared the groups regarding the S2+3 volume changes after PVE. RESULTS: Of 178 enrolled patients, 38 underwent R3PVE for right hepatic trisectionectomy and 140 underwent R2PVE for right hepatectomy. Twenty-eight patients from each group were respectively matched. The median absolute volume increase in (146 cm3 vs 70 cm3 ), hypertrophy rate of (52.4% vs 32.3%), and kinetic growth rate of (3.1 %/week vs 2.0 %/week) S2+3 were significantly higher in the R3PVE group than in the R2PVE group. In the pre-matched cohort, the rate of posthepatectomy liver failure and postoperative hospital stay did not significantly differ between the patients who underwent right hepatic trisectionectomy and right hepatectomy. CONCLUSION: R3PVE increased the S2+3 volume more effectively than R2PVE in patients with biliary carcinoma.

DOI： 10.1002/jhbp.723

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

We retrospectively evaluated the frequency of unexpected accumulation of radioactive iodine on the post-therapy whole-body scan (Rx-WBS) after radioactive iodine (RAI) ablation therapy in patients with differentiated thyroid cancer (DTC). We searched our institutional database for Rx-WBSs of DTC patients who underwent RAI ablation or adjuvant therapy between 2012 and 2019. Patients with distant metastasis diagnosed by CT or PET/CT before therapy, and those had previously received RAI therapy were excluded. In total, 293 patients (201 female and 92 male, median age 54 years) were selected. Two nuclear medicine physicians interpreted the Rx-WBS images by determining the visual intensity of radioiodine uptake by the thyroid bed, cervical and mediastinal lymph nodes, lungs, and bone. Clinical features of the patients with and without the metastatic accumulation were compared by chi-square test and median test. Logistic regression analyses were performed to compare the association between the presence of metastatic accumulation and these clinical factors. Eighty-four of 293 patients (28.7%) showed metastatic accumulation. Patients with metastatic RAI accumulation showed a significantly higher frequency of pathological N1 (pN1) and serum thyroglobulin (Tg) > 1.5 ng/ml under TSH stimulation (p = 0.035 and p = 0.031, respectively). Logistic regression analysis indicated that a serum Tg > 1.5 ng/ml was significantly correlated with the presence of metastatic accumulation (odds ratio = 1.985; p = 0.033). In conclusion, Patients with Tg > 1.5 ng/ml were more likely to show metastatic accumulation. In addition, the presence of lymph node metastasis at the initial thyroid surgery was also associated with this unexpected metastatic accumulation.

DOI： 10.18999/nagjms.82.2.205

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PubMed

担当区分：最終著者   記述言語：日本語  

担当区分：筆頭著者,　責任著者   記述言語：日本語  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: In the previous treatment planning system (TPS) for CyberKnife (CK), multileaf collimator (MLC)-based treatment plans could be created only by using the finite-size pencil beam (FSPB) algorithm. Recently, a new TPS, including the FSPB with lateral scaling option (FSPB+) and Monte Carlo (MC) algorithms, was developed. In this study, we performed basic and clinical end-to-end evaluations for MLC-based CK tumor-tracking radiotherapy using the MC, FSPB+, and FSPB. METHODS: Water- and lung-equivalent slab phantoms were combined to obtain the percentage depth dose (PDD) and off-center ratio (OCR). The CK M6 system and Precision TPS were employed, and PDDs and OCRs calculated by the MC, FSPB+, and FSPB were compared with the measured doses obtained for 30.8 × 30.8 mm2 and 60.0 × 61.6 mm2 fields. A lung motion phantom was used for clinical evaluation and MLC-based treatment plans were created using the MC. The doses were subsequently recalculated using the FSPB+ and FSPB, while maintaining the irradiation parameters. The calculated doses were compared with the doses measured using a microchamber (for target doses) or a radiochromic film (for dose profiles). The dose volume histogram (DVH) indices were compared for all plans. RESULTS: In homogeneous and inhomogeneous phantom geometries, the PDDs calculated by the MC and FSPB+ agreed with the measurements within ±2.0% for the region between the surface and a depth of 250 mm, whereas the doses calculated by the FSPB in the lung-equivalent phantom region were noticeably higher than the measurements, and the maximum dose differences were 6.1% and 4.4% for the 30.8 × 30.8 mm2 and 60.0 × 61.6 mm2 fields, respectively. The maximum distance to agreement values of the MC, FSPB+, and FSPB at the penumbra regions of OCRs were 1.0, 0.6, and 1.1 mm, respectively, but the best agreement was obtained between the MC-calculated curve and measurements at the boundary of the water- and lung-equivalent slabs, compared with those of the FSPB+ and FSPB. For clinical evaluations using the lung motion phantom, under the static motion condition, the dose errors measured by the microchamber were -1.0%, -1.9%, and 8.8% for MC, FSPB+, and FSPB, respectively; their gamma pass rates for the 3%/2 mm criterion comparing to film measurement were 98.4%, 87.6%, and 31.4% respectively. Under respiratory motion conditions, there was no noticeable decline in the gamma pass rates. In the DVH indices, for most of the gross tumor volume and planning target volume, significant differences were observed between the MC and FSPB, and between the FSPB+ and FSPB. Furthermore, significant differences were observed for lung Dmean , V15 Gy , and V20 Gy between the MC, FSPB+, and FSPB. CONCLUSIONS: The results indicate that the doses calculated using the MC and FSPB+ differed remarkably in inhomogeneous regions, compared with the FSPB. Because the MC was the most consistent with the measurements, it is recommended for final dose calculations in inhomogeneous regions such as the lung. Furthermore, the sufficient accuracy of dose delivery using MLC-based tumor-tracking radiotherapy by CK was demonstrated for clinical implementation.

DOI： 10.1002/mp.14013

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BMJ PUBLISHING GROUP  

Introduction Iodinated contrast media are commonly used in medical imaging and can cause hypersensitivity reactions, including rare but severe life-threatening reactions. Although several prophylactic approaches have been proposed for severe reactions, their effects remain unclear. Therefore, we aim to review systematically the preventive effects of pharmacologic and non-pharmacologic interventions and predictors of acute, hypersensitivity reactions.Methods and analysis We will search the PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases from 1 January 1990 through 31 December 2019 and will examine the bibliographies of eligible studies, pertinent review articles and clinical practice guidelines. We will include prospective and retrospective studies of any design that evaluated the effects of pharmacological and non-pharmacological preventive interventions for adverse reactions of non-ionic iodinated contrast media. Two assessors will independently extract the characteristics of the study and intervention and the quantitative results. Two independent reviewers will assess the risk of bias using standard design-specific validity assessment tools. The primary outcome will be reduction in acute contrast media-induced hypersensitivity reactions. The secondary outcomes will include characteristics associated with the development of contrast media-induced acute hypersensitivity reactions, and adverse events associated with specific preventive interventions. Unique premedication regimens (eg, dose, drug and duration) and non-pharmacological strategies will be analysed separately. Average-risk and high-risk patients will be considered separately. A meta-analysis will be performed if appropriate.Ethics and dissemination Ethics approval is not applicable, as this will be a secondary analysis of publicly available data. The results of the analysis will be submitted for publication in a peer reviewed journal.

DOI： 10.1136/bmjopen-2019-033023

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PubMed

担当区分：最終著者   記述言語：日本語  

担当区分：筆頭著者   記述言語：日本語  

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(株)Gakken  

＜文献概要＞肺癌の臨床病期分類(TNM分類)は主に画像診断に基づいて行われる.2017年に改訂されたTNM分類では,T因子(サイズ)の診断が複雑になった.病理学的浸潤径に相当する充実成分径の計測はthinsection CTで行うのが基本であるが,3次元CTやPET/CTを利用することで精度の向上が期待できる.

その他リンク： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2020&ichushi_jid=J00235&link_issn=&doc_id=20200408090014&doc_link_id=10.15105%2FGZ.0000001656&url=https%3A%2F%2Fdoi.org%2F10.15105%2FGZ.0000001656&type=%88%E3%8F%91.jp_%83I%81%5B%83%8B%83A%83N%83Z%83X&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00024_2.gif

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1038/s41598-019-57306-w

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.1002/jmri.26892

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-019-00904-5

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PubMed

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：産業開発機構(株)  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Recently, the use of 3D real inversion recovery (3D-real IR) imaging has been proposed for the evaluation of endolymphatic hydrops (EH). This method shows similar contrast between the endolymphatic and perilymphatic spaces and surrounding bone compared with the hybrid of reversed image of positive endolymph signal and native image of perilymph signal multiplied with heavily T2-weighted MR cisternography (HYDROPS-Mi2) image. We measured the volume of the endolymphatic space using 3D-real IR and HYDROPS-Mi2 images, and compared the measurements obtained with both techniques. METHODS: HYDROPS-Mi2 and 3D-real IR images were obtained for 30 ears from 15 patients with clinical suspicion of EH; imaging was performed 4 h after intravenous administration of a single dose of gadolinium-based contrast agent. We measured the volume of the endolymphatic space in the cochlea and vestibule by manually drawing the regions of interest. The correlation between endolymphatic volume determined from HYDROPS-Mi2 images and 3D-real IR images was calculated. RESULTS: There was a strong positive linear correlation between the cochlear and vestibular endolymphatic volume determined from HYDROPS-Mi2 and 3D-real IR images. The Spearman's rank correlation coefficient (ρ) between the measurements obtained with both images was 0.805 (P < 0.001) for the cochlea and 0.826 (P < 0.001) for the vestibule. CONCLUSION: The endolymphatic volume measured using 3D-real IR images strongly correlated with that measured using HYDROPS-Mi2 images. Thus, 3D-real IR imaging might be a suitable method for the measurement of endolymphatic volume.

DOI： 10.2463/mrms.mp.2019-0013

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.bc.2019-0099

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2019-0048

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2019-0182

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

DOI： 10.2463/mrms.mp.2019-0016

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Evaluate in vivo hemodynamic and morphological biomarkers of intracranial aneurysms, using magnetic resonance fluid dynamics (MRFD) and MR-based patient specific computational fluid dynamics (CFD) in order to assess the risk of rupture. METHODS: Forty-eight intracranial aneurysms (10 ruptured, 38 unruptured) were scrutinized for six morphological and 10 hemodynamic biomarkers. Morphological biomarkers were calculated based on 3D time-of-flight magnetic resonance angiography (3D TOF MRA) in MRFD analysis. Hemodynamic biomarkers were assessed using both MRFD and CFD analyses. MRFD was performed using 3D TOF MRA and 3D cine phase-contrast magnetic resonance imaging (3D cine PC MRI). CFD was performed utilizing patient specific inflow-outflow boundary conditions derived from 3D cine PC MRI. Univariate analysis was carried out to identify statistically significant biomarkers for aneurysm rupture and receiver operating characteristic (ROC) analysis was performed for the significant biomarkers. Binary logistic regression was performed to identify independent predictive biomarkers. RESULTS: Morphological biomarker analysis revealed that aneurysm size [P = 0.021], volume [P = 0.035] and size ratio [P = 0.039] were statistically significantly different between the two groups. In hemodynamic biomarker analysis, MRFD results indicated that ruptured aneurysms had higher oscillatory shear index (OSI) [OSI.max, P = 0.037] and higher relative residence time (RRT) [RRT.ave, P = 0.035] compared with unruptured aneurysms. Correspondingly CFD analysis demonstrated significant differences for both average and maximum OSI [OSI.ave, P = 0.008; OSI.max, P = 0.01] and maximum RRT [RRT.max, P = 0.045]. ROC analysis revealed AUC values greater than 0.7 for all significant biomarkers. Aneurysm volume [AUC, 0.718; 95% CI, 0.491-0.946] and average OSI obtained from CFD [AUC, 0.774; 95% CI, 0.586-0.961] were retained in the respective logistic regression models. CONCLUSION: Both morphological and hemodynamic biomarkers have significant influence on intracranial aneurysm rupture. Aneurysm size, volume, size ratio, OSI and RRT could be potential biomarkers to assess aneurysm rupture risk.

DOI： 10.2463/mrms.mp.2019-0107

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVE: To evaluate the associations between computer-aided diagnosis (CAD)-generated kinetic volume parameters and survival in triple-negative breast cancer (TNBC) patients. METHODS: 40 patients with TNBC who underwent pre-operative MRI between March 2008 and March 2014 were included. We analyzed CAD-generated parameters on dynamic contrast-enhanced MRI, visual MRI assessment, and histopathological data. Cox proportional hazards models were used to determine associations with survival outcomes. RESULTS: 12 of the 40 (30.0%) patients experienced recurrence and 7 died of breast cancer after a median follow-up of 73.6 months. In multivariate analysis, higher percentage volume (%V) with more than 200% initial enhancement rate correlated with worse disease-specific survival (hazard ratio, 1.12; 95% confidence interval, 1.02-1.22; p-value, 0.014) and higher %V with more than 100% initial enhancement rate followed by persistent curve type at 30% threshold correlated with worse disease-specific survival (hazard ratio, 1.33; 95% confidence interval, 1.10-1.61; p-value, 0.004) and disease-free survival (hazard ratio, 1.27; 95% confidence interval, 1.12-1.43; p-value, 0.000). CONCLUSION: CAD-generated kinetic volume parameters may correlate with survival in TNBC patients. Further study would be necessary to validate our results on larger cohorts. ADVANCES IN KNOWLEDGE: CAD generated kinetic volume parameters on breast MRI can predict recurrence and survival outcome of patients in TNBC. Varying the enhancement threshold improved the predictive performance of CAD generated kinetic volume parameter.

DOI： 10.1259/bjr.20190712

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: 2D cine phase contrast (PC)-MRI is a standard velocimetry for the superior mesenteric artery (SMA); however, the optimal localization of the measurement plane has never been fully discussed previously. The purpose of this Institutional Review Board approved prospective and single arm study is to test whether flow velocimetry of the SMA with combined use of 2D cine PC-MRI and meal challenge is dependent on the localizations of the measurement planes and to seek optimal section for velocimetry. METHODS: Seven healthy volunteers underwent cardiac phase resolved ECG gated 2D cine PC-MRI pre- and 30 min post-meal challenge at three measurement planes: proximal, curved mid section and distal straight section of the SMA at 3T. 4D Flow using 3D cine PC-MRI with vastly undersampled isotropic projection imaging (PC VIPR) was also performed right after 2D cine PC-MRI to delineate the flow dynamics within the SMA using streamline analysis. Two radiologists measured flow velocities, and rated the appearances of the abnormal flow in the SMA on streamlines derived from the 4D Flow and the computational fluid dynamics (CFD). RESULTS: 2D cine PC-MRI measured increased temporally averaged flow velocity (mm/s) after the meal challenge only in the proximal (129.3 vs. 97.8, P = 0.0313) and distal section (166.9 vs. 96.2, P = 0.0313), not in the curved mid section (113.1 vs. 85.5, P = 0.0625). The average velocities were highest and their standard errors (8.5-26.5) were smallest at the distal straight section both before and after the meal challenge as compared with other sections. The streamline analysis depicted more frequent appearances of vertical or helical flow in the curved mid section both on 4D Flow and CFD (κ: 0.27-0.68). CONCLUSION: SMA velocimetry with 2D cine PC-MRI was dependent on the localization of the measurement planes. Distal straight section, not in the curved mid section is recommended for MR velocimetry.

DOI： 10.2463/mrms.mp.2019-0089

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PubMed

担当区分：最終著者   掲載種別：研究論文（学術雑誌）  

DOI： 10.1097/RCT.0000000000001052

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: To characterize the non-laminar flow dynamics and resultant decreased wall shear stress (WSS) and high oscillatory shear index (OSI) of the infrarenal abdominal aortic dilatation, cardiac phase-resolved 3D phase-contrast MRI (4D-flow MRI) was performed. METHODS: The prospective single-arm study was approved by the Institutional Review Board and included 18 subjects (median 67.5 years) with the dilated infrarenal aorta (median diameter 35 mm). 4D-flow MRI was conducted on a 1.5T MRI system. On 3D streamline images, laminar and non-laminar (i.e., vortex or helical) flow patterns were visually assessed both for the dilated aorta and for the undilated upstream aorta. Cardiac phase-resolved flow velocities, WSS and OSI, were also measured for the dilated aorta and the upstream undilated aorta. RESULTS: Non-laminar flow represented by vortex or helical flow was more frequent and overt in the dilated aorta than in the undilated upstream aorta (P < 0.0156) with a very good interobserver agreement (weighted kappa: 0.82-1.0). The WSS was lower, and the OSI was higher on the dilated aortic wall compared with the proximal undilated segments. In mid-systole, mean spatially-averaged WSS was 0.20 ± 0.016 Pa for the dilated aorta vs. 0.68 ± 0.071 Pa for undilated upstream aorta (P < 0.0001), and OSI on the dilated aortic wall was 0.093 ± 0.010 vs. 0.041 ± 0.0089 (P = 0.013). The maximum values and the amplitudes of the WSS at the dilated aorta were inversely proportional to the ratio of dilated/undilated aortic diameter (r = -0.694, P = 0.0014). CONCLUSION: 4D-flow can characterize abnormal non-laminar flow dynamics within the dilated aorta in vivo. The wall of the infrarenal aortic dilatation is continuously and increasingly affected by atherogenic stimuli due to the flow disturbances represented by vortex or helical flow, which is reflected by lower WSS and higher OSI.

DOI： 10.2463/mrms.mp.2019-0188

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：日本語  

担当区分：筆頭著者,　責任著者   記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(一社)日本神経学会  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jvir.2019.06.022

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PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：医学図書出版(株)  

担当区分：責任著者   記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本医学放射線学会  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-019-47922-x

Web of Science

PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18999/nagjms.81.3.351

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1186/s13014-019-1333-x

Web of Science

PubMed

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1186/s40644-019-0219-3

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-019-00826-2

Web of Science

PubMed

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(株)インナービジョン  

2006年から始まった第三次AIブームによりAIの研究が加速度的に進み、現在ではスマートフォンのカメラや音声入力など身近なものに活用されている。放射線医学においては古くから人工知能(AI)を用いた研究が行われ、臨床にも応用されていた。最近では、さらに発展したAIを用いたCADの開発が盛んであり、世界中の研究者が開発を競っている。本稿では、加速度的に進歩するAIと放射線医学とのかかわりについて、主に胸部画像診断の観点から現在の状況と問題点についてまとめ、実際の研究例について提示する。(著者抄録)

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-019-00828-0

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18999/nagjms.81.2.233

Web of Science

PubMed

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(株)Gakken  

その他リンク： https://search.jamas.or.jp/default/link?pub_year=2019&ichushi_jid=J00235&link_issn=&doc_id=20190607110004&doc_link_id=10.15105%2FGZ.0000001162&url=https%3A%2F%2Fdoi.org%2F10.15105%2FGZ.0000001162&type=%E5%8C%BB%E6%9B%B8.jp_%E3%82%AA%E3%83%BC%E3%83%AB%E3%82%A2%E3%82%AF%E3%82%BB%E3%82%B9&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00024_2.gif

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1097/RLU.0000000000002591

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00261-019-01925-4

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1097/MAO.0000000000002175

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(NPO)日本肺癌学会  

記述言語：日本語  

記述言語：日本語  

担当区分：責任著者   記述言語：日本語  

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18999/nagjms.81.1.41

Web of Science

PubMed

記述言語：日本語  

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本医学放射線学会  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(公社)日本医学放射線学会  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00016489.2018.1521526

PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：(株)学研メディカル秀潤社  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2463/mrms.mp.2018-0043

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11604-018-0790-8

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）