Faculty Profiles - NAGANAWA, Shinji

Papers - NAGANAWA, Shinji

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MR Imaging of Endolymphatic Hydrops: Utility of iHYDROPS-Mi2 Combined with Deep Learning Reconstruction Denoising. Reviewed

Shinji Naganawa, Rei Nakamichi, Kazushige Ichikawa, Mariko Kawamura, Hisashi Kawai, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 3 ) page： 272 - 279 2021

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

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

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PubMed

Three Dimensional Ultra-short Echo Time MRI Can Depict Cholesterol Components of Gallstones Bright. Reviewed

Mamoru Takahashi, Yasuo Takehara, Kenji Fujisaki, Tomoyuki Okuaki, Yukiko Fukuma, Norihiro Tooyama, Katsutoshi Ichijo, Tomoyasu Amano, Satoshi Goshima, Shinji Naganawa

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 4 ) page： 359 - 370 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

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

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Relationship between Time-dependent Signal Changes in Parasagittal Perivenous Cysts and Leakage of Gadolinium-based Contrast Agents into the Subarachnoid Space. Reviewed

Shinji Naganawa, Rintaro Ito, Rei Nakamichi, Mariko Kawamura, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 4 ) page： 378 - 384 2021

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

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

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Relationship between Parasagittal Perivenous Cysts and Leakage of Gadolinium-based Contrast Agents into the Subarachnoid Space around the Cortical Veins after Intravenous Administration. Reviewed

Shinji Naganawa, Rintaro Ito, Rei Nakamichi, Mariko Kawamura, Hisashi Kawai, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 3 ) page： 245 - 252 2021

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

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

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Portal Vein Stenosis Following Liver Transplantation Hemodynamically Assessed with 4D-flow MRI before and after Portal Vein Stenting. Reviewed

Ryota Hyodo, Yasuo Takehara, Takashi Mizuno, Kazushige Ichikawa, Yasuhiro Ogura, Shinji Naganawa

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 20 ( 3 ) page： 231 - 235 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

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

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特集「世界の医療・Radiology：海外事情を覗き見よう」ドイツ編 Reviewed

長縄慎二

JCRニュース (日本放射線科専門医会・医会誌) Vol. 238 ( - ) page： 11 - 13 2021

A case of stent-graft implantation for postpancreaticoduodenectomy hemorrhage in a patient with a reconstructed gastric tube

Tomohiro Komada, Yasushi Tachi, Ken Nagasaka, Suguru Yamada, Masaya Matsushima, Yutaro Sakaki, Shinji Naganawa

Radiology Case Reports Vol. 15 ( 12 ) page： 2710 - 2713 2020.12

Evaluation of magnetic resonance angiography as a possible alternative to rotational angiography or computed tomography angiography for assessing cerebrovascular computational fluid dynamics. Reviewed International journal

Yuya Yoneyama, Haruo Isoda, Kenta Ishiguro, Masaki Terada, Masaki Kamiya, Kenichi Otsubo, Roshani Perera, Takashi Mizuno, Atsushi Fukuyama, Kazuya Takiguchi, Tomoya Watanabe, Takafumi Kosugi, Yoshiaki Komori, Shinji Naganawa

Physical and engineering sciences in medicine Vol. 43 ( 4 ) page： 1327 - 1337 2020.12

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

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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【基調論文】CTおよびMRIなどの画像診断装置の今後の展望 Reviewed

長縄慎二

月間新医療データブック・シリーズ　医療機器システム白書 Vol. - ( - ) page： 14 - 18 2020.12

【特集】　マネジメントに苦慮する疾患： Is it benign, malignant or insignificant? 1. 甲状腺病変の診断とマネジメント Invited Reviewed

石垣聡子、佐竹弘子、松本篤子、林　葉子、清水友理、長縄慎二

日獨医報 Vol. 65 ( 1 ) page： 5 - 11 2020.12

Identifying the brain's connector hubs at the voxel level using functional connectivity overlap ratio. Reviewed International journal

Epifanio Bagarinao, Hirohisa Watanabe, Satoshi Maesawa, Daisuke Mori, Kazuhiro Hara, Kazuya Kawabata, Reiko Ohdake, Michihito Masuda, Aya Ogura, Toshiyasu Kato, Shuji Koyama, Masahisa Katsuno, Toshihiko Wakabayashi, Masafumi Kuzuya, Minoru Hoshiyama, Haruo Isoda, Shinji Naganawa, Norio Ozaki, Gen Sobue

NeuroImage Vol. 222 page： 117241 - 117241 2020.11

Language：English Publishing type：Research paper (scientific journal)

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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Neurofluid Dynamics and the Glymphatic System: A Neuroimaging Perspective. Reviewed International journal

Toshiaki Taoka, Shinji Naganawa

Korean journal of radiology Vol. 21 ( 11 ) page： 1199 - 1209 2020.11

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

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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Aging Impacts the Overall Connectivity Strength of Regions Critical for Information Transfer Among Brain Networks Reviewed International journal

Epifanio Bagarinao, Hirohisa Watanabe, Satoshi Maesawa, Daisuke Mori, Kazuhiro Hara, Kazuya Kawabata, Noritaka Yoneyama, Reiko Ohdake, Kazunori Imai, Michihito Masuda, Takamasa Yokoi, Aya Ogura, Toshiaki Taoka, Shuji Koyama, Hiroki C. Tanabe, Masahisa Katsuno, Toshihiko Wakabayashi, Masafumi Kuzuya, Minoru Hoshiyama, Haruo Isoda, Shinji Naganawa, Norio Ozaki, Gen Sobue

Frontiers in Aging Neuroscience Vol. 12 page： 592469 - 592469 2020.10

Language：English Publishing type：Research paper (scientific journal) Publisher：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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Significance of high signal intensity in the endolymphatic duct on magnetic resonance imaging in ears with otological disorders. Reviewed International journal

Kyoko Morimoto, Tadao Yoshida, Masumi Kobayashi, Satofumi Sugimoto, Naoki Nishio, Masaaki Teranishi, Shinji Naganawa, Michihiko Sone

Acta oto-laryngologica Vol. 140 ( 10 ) page： 818 - 822 2020.10

Language：English Publishing type：Research paper (scientific journal)

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

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Change of White Matter Integrity in Children With Hematopoietic Stem Cell Transplantation. Reviewed International journal

Yoko Sakaguchi, Jun Natsume, Hiroyuki Kidokoro, Masaharu Tanaka, Yu Okai, Yuji Ito, Hiroyuki Yamamoto, Atsuko Ohno, Tomohiko Nakata, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka, Hideki Muramatsu, Shinji Naganawa, Yoshiyuki Takahashi

Pediatric neurology Vol. 111 page： 78 - 84 2020.10

Language：English Publishing type：Research paper (scientific journal)

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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A review on the use of artificial intelligence for medical imaging of the lungs of patients with coronavirus disease 2019. Reviewed International journal

Rintaro Ito, Shingo Iwano, Shinji Naganawa

Diagnostic and interventional radiology (Ankara, Turkey) Vol. 26 ( 5 ) page： 443 - 448 2020.9

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

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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第21回山形めまい研究会　特別講演Ⅰ　MR imaging of endolymphatic hydrops; What is right, what is wrong, and what is new Invited Reviewed

長縄慎二

耳鼻咽喉科山形 (日本耳鼻咽喉科学会山形県地方部会誌) Vol. 24 ( - ) page： 54 - 55 2020.9

Changes in white matter fiber density and morphology across the adult lifespan: A cross-sectional fixel-based analysis. Reviewed International journal

Shao Wei Choy, Epifanio Bagarinao, Hirohisa Watanabe, Eric Tatt Wei Ho, Satoshi Maesawa, Daisuke Mori, Kazuhiro Hara, Kazuya Kawabata, Noritaka Yoneyama, Reiko Ohdake, Kazunori Imai, Michihito Masuda, Takamasa Yokoi, Aya Ogura, Toshiaki Taoka, Shuji Koyama, Hiroki C Tanabe, Masahisa Katsuno, Toshihiko Wakabayashi, Masafumi Kuzuya, Minoru Hoshiyama, Haruo Isoda, Shinji Naganawa, Norio Ozaki, Gen Sobue

Human brain mapping Vol. 41 ( 12 ) page： 3198 - 3211 2020.8

Language：English Publishing type：Research paper (scientific journal)

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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Efficacy and safety of accelerated fractionated radiotherapy without elective nodal irradiation for T3N0 glottic cancer without vocal cord fixation. Reviewed International journal

Masayuki Okumura, Atsushi Motegi, Sadamoto Zenda, Naoki Nakamura, Hidehiro Hojo, Masaki Nakamura, Yasuhiro Hirano, Shun-Ichiro Kageyama, Satoko Arahira, Raturi Vijay Parshuram, Hirofumi Kuno, Ryuichi Hayashi, Makoto Tahara, Yoshiyuki Itoh, Shinji Naganawa, Tetsuo Akimoto

Head & neck Vol. 42 ( 8 ) page： 1775 - 1782 2020.8

Language：English Publishing type：Research paper (scientific journal)

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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ロボット支援前立腺全摘除術後の難治性乳び腹水に対してリンパ管塞栓術が奏功した一例 Reviewed

兵藤良太, 山田恵一郎, 堀口瞭太, 伊藤準, 松島正哉, 駒田智大, 大脇貴之, 竹原康雄, 長縄慎二

日本インターベンショナルラジオロジー学会雑誌 Vol. 35 ( Suppl. ) page： 290 - 290 2020.8

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Papers - NAGANAWA, Shinji