Researcher basic information

• 医学博士, 北海道大学, Mar. 2018

• https://researchmap.jp/hkameda?lang=en

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201801008950465513

• 70829887

• 201801008950465513

• 生化学
• 分子生物学
• 分子イメージング
• 画像
• 神経放射線
• MRI

• Life Science, Radiological sciences

• Bachelor's degree program, School of Dental Medicine
• Doctoral (PhD) degree program, Graduate school of Dental Medicine

Research activity information

• Feb. 2026, 第55回日本神経放射線学会, 優秀展示賞
• Dec. 2025, 北海道大学医学部同窓会, 令和７年度フラテ研究奨励賞
• Apr. 2025, 日本磁気共鳴医学会, ISMRM Travel Award 2024
• Sep. 2024, 第52回日本磁気共鳴医学会大会 大会長賞（最優秀賞）
  17O標識水のくも膜下腔直接注入とプロトンMRIによるラット大脳表面の水動態の可視化
• Feb. 2024, 日本神経放射線学会, 令和5 (2023)年度 日本神経放射線学会研究助成金制度
  「17O標識水を用いた髄液動態の可視化」
• May 2020, 第79回日本医学放射線学会総会イメージインタープリテーションセッション 成績優秀賞（第1位）
• 2015, アジア・オセアニア神経放射線学会, Magna Cum Laude
• Mar. 2012, 第31回 高桑奨学金基金
• Sep. 2009, 第5回 音羽博次奨学基金

• Image Quality Assessment of the External Carotid Artery and Its Branches on Ultra-High-Resolution Head and Neck Computed Tomography Angiography Using a High-Resolution 0.25-mm Detector and Deep Learning Reconstruction.
  Motoma Kanaya; Noriyuki Fujima; Koji Yamasaki; Yuki Takano; Yohei Ikebe; Taisuke Harada; Yukie Shimizu; Hiroyuki Kameda; Yuya Hirano; Aogu Yamaguchi; Satoshi Kano; Akihiro Homma; Kohsuke Kudo
  AJNR. American journal of neuroradiology, 25 Apr. 2026, [International Magazine]
  English, Scientific journal, BACKGROUND AND PURPOSE: Deep learning reconstruction can improve image quality of CTA, but its benefit for visualizing small-caliber external carotid artery branches on ultra-high-resolution CTA remains unclear. We evaluated the image quality of ultra-high-resolution CTA of the external carotid artery using filtered back projection, hybrid iterative reconstruction, and deep learning reconstruction, and assessed its added value for visualizing small-caliber external carotid artery branches and tumor-feeding vessels. MATERIALS AND METHODS: In this single-center study, we retrospectively analyzed 24 patients who underwent ultra-high-resolution CTA for evaluation of head/neck tumors or an elongated styloid process. Axial images (0.25-mm slice thickness) were reconstructed with each method. The quantitative analyses included attenuation, image noise, SNR, contrast-to-noise ratio, edge rise distance, and edge rise slope for the external carotid artery trunk and 11 branches. Two radiologists (each with 8 years of experience) independently assessed overall image quality, peripheral vessel sharpness, artifact severity, and clarity of the tumor-margin and intratumoral vessels, using a four-point Likert scale. Objective and subjective metrics were compared using nonparametric repeated-measures tests. Interobserver agreement was assessed using quadratic-weighted κ-value. RESULTS: Deep learning reconstruction provided the lowest image noise, highest SNR, and highest contrast-to-noise ratio for the external carotid artery trunk (all P <.001). For the 11 branches, deep learning reconstruction demonstrated the shortest edge rise distance (0.795 [0.751-0.824] mm vs. 0.982 [0.942-1.017] for hybrid iterative reconstruction and 1.044 [1.002-1.157] for filtered back projection), the highest edge rise slope(613.4 [586.1-686.5] vs. 393.1 [366.7-442.6] and 477.4 [446.9-524.7]), and the highest contrast-to-noise ratio (40.6 [36.0-43.2] vs. 16.7 [14.9-20.2] and 9.8 [8.3-11.0]) (all P <.001). Subjective scores were highest for deep learning reconstruction across all categories (median overall image quality: 4 for deep learning reconstruction, 3 for hybrid iterative reconstruction, and 2 for filtered back projection). Deep learning reconstruction also provided significantly superior visualization of tumor-margin and intratumoral vessels (P <.001). Interobserver agreement was substantial for all qualitative metrics (κ = 0.67-0.76). CONCLUSIONS: Deep learning reconstruction markedly improves the quality of ultra-high-resolution CTA images of the external carotid artery system by enhancing vessel sharpness, contrast resolution, and tumor-feeding vessel conspicuity, although further validation in larger cohorts is needed to confirm these findings.
• Improved visualization of perivascular spaces on T2-weighted imaging with deep learning-based denoising and super-resolution reconstruction.
  Yuya Hirano; Noriyuki Fujima; Hiroyuki Kameda; Hiroyuki Hamaguchi; Kinya Ishizaka; Jihun Kwon; Masami Yoneyama; Kohsuke Kudo
  Scientific reports, 18 Apr. 2026, [International Magazine]
  English, Scientific journal, This prospective study evaluated the ability of a deep learning-based denoising followed by super-resolution function (SR-DL) to improve the visualization of perivascular spaces (PVSs) on T2-weighted imaging (T2WI). Ten healthy volunteers underwent brain MRI using T2WI with three acquisition voxel sizes (1.0 × 1.0 mm, 0.8 × 0.8 mm, and 0.5 × 0.5 mm), each reconstructed to half-size in-plane resolution. For each acquisition, image sets were generated using compressed-sensing sensitivity-encoding (CS-SENSE) and SR-DL, and a fully sampled high-resolution dataset with a reduction factor of 1 was obtained as a reference. Quantitative evaluation consisted of counting PVSs in the centrum semiovale and basal ganglia by two radiologists. In addition, contrast ratio (CR) between PVSs and adjacent brain parenchyma was measured using region-of-interest analysis. The utility of SR-DL T2WIs for PVS segmentation was also assessed using an existing automated method on both CS-SENSE and DL-SR images. Qualitative visibility was evaluated on a four-point scale. SR-DL significantly increased the number of detectable PVSs compared with CS-SENSE at medium- and high-resolution voxel sizes for both readers in both regions (P < 0.05 to < 0.001). SR-DL demonstrated significantly higher CRs between PVSs and adjacent white matter than CS-SENSE across all assessments (all P < 0.05). Automated PVS segmentation also showed significantly more detected PVSs with SR-DL than with CS-SENSE at all voxel sizes (all P < 0.05). Qualitative assessment also demonstrated consistently higher visibility scores with SR-DL across all voxel sizes (P < 0.05). These findings indicate that SR-DL reconstruction markedly improves both quantitative detectability and qualitative visibility of PVSs on T2WI without prolonging acquisition time, potentially facilitating more reliable PVS assessment and enhancing the utility of PVS-based imaging biomarkers.
• A case of pseudoaneurysm of the descending palatine artery after orthognathic surgery.
  Yuta Kanno; Shigeru Yamano; Tomoka Shima; Akiko Takeuchi; Hiroyuki Kameda; Masaaki Suzuka; Nanami Iwai; Daisuke Yoshida; Kazuyuki Minowa
  Oral radiology, 13 Apr. 2026, [Domestic magazines]
  English, Scientific journal, Orthognathic surgery is widely performed to correct dentofacial deformities and is generally associated with a low risk of vascular complications. This report describes a case of pseudoaneurysm of the descending palatine artery following orthognathic surgery. The patient was a woman in her 50s who was diagnosed with dentofacial deformity and underwent orthognathic surgery involving both the maxilla and mandible. Postoperatively, she developed recurrent epistaxis that was difficult to control. Dynamic contrast-enhanced computed tomography and angiography were performed to identify the source of bleeding and revealed a pseudoaneurysm that was treated successfully by endovascular embolization. The etiology of bleeding after orthognathic surgery, including pseudoaneurysm formation, remains incompletely understood. In this case, substantial posterior repositioning of the maxilla was performed. Although there is a suggestion of a correlation between the extent of repositioning of bone fragments and vascular injury, this association has yet to be confirmed by large-scale studies. Preoperative computed tomography in this case also demonstrated calcification in the carotid arteries, suggesting underlying arteriosclerosis. In orthopedic surgery involving the lower limbs, iatrogenic arterial injury occurs more often in patients with atherosclerosis, implicating arterial fragility as a contributing factor. Decreased arterial elasticity as a result of atherosclerosis may increase the risk of vascular injury during orthognathic procedures. Although no definitive association has been established between atherosclerosis and vascular complications such as pseudoaneurysm, preoperative imaging findings may provide valuable information when assessing risk factors for postoperative complications.
• χ-separation Insights into Whole-brain Characterization of Age-related Patterns of Susceptibility in Healthy Aging.
  Simi Zhou; Yoshitaka Bito; Hiroyuki Kameda; Yohei Ikebe; Yukie Shimizu; Noriyuki Fujima; Taisuke Harada; Naoya Kinota; Daisuke Kato; Takaaki Fujii; Xiawei Bai; Byeongpil Moon; Jongho Lee; Kohsuke Kudo
  NeuroImage, 121599, 121599, 19 Nov. 2025, [International Magazine]
  English, Scientific journal, Quantitative Susceptibility Mapping (QSM) enables noninvasive assessment of brain tissue composition, but conventional approaches provide only a composite measure that merges paramagnetic and diamagnetic contributions, limiting biological specificity. Recent advances in χ-separation overcome this limitation by separating χ-paramagnetic (χ-para) and χ-diamagnetic (χ-dia) components within a single voxel. This study aimed to comprehensively characterize age-related trajectories of paramagnetic and diamagnetic susceptibility changes across the adult lifespan, thereby establishing normative reference patterns for interpreting neuropathological alterations. A total of 131 healthy adults (62 males, 69 females; age 21-89 years) underwent multi-echo gradient echo. χ-separation was applied to generate χ-para, χ-dia, and total susceptibility (χ-tot) maps. Median susceptibility was extracted using a customized 69-region parcellation (cortical, subcortical, and white matter regions). Age effects were assessed with linear and non-linear regression analyses. χ-para exhibited positive linear, quadratic, or exponential associations with aging in caudate, putamen, substantia nigra (SN), red nucleus (RN), subthalamic nucleus (STN), thalamic subdivisions, superior frontal areas around the primary motor cortex, parietal, temporal, occipital, limbic, and insular cortices, splenium of corpus callosum (CC), posterior limb of internal capsule (PLIC,) and anterior of corona radiata (CR). |χ-dia| showed negative linear or quadratic declines in genu, body, and splenium of CC, PLIC, anterior and posterior of CR, posterior thalamic radiation, SN, RN, STN, ventral pallidum, pulvinar, and superior frontal regions. By explicitly separating paramagnetic and diamagnetic components, χ-separation provided novel insights into microstructural age-dependent trajectories, offering biologically specific normative references for iron accumulation and myelin decline, with implications for studying neurodegenerative disorders.
• Ultra-fast whole-brain T2-weighted imaging in 7 seconds using dual-type deep learning reconstruction with single-shot acquisition: clinical feasibility and comparison with conventional methods.
  Yohei Ikebe; Noriyuki Fujima; Hiroyuki Kameda; Taisuke Harada; Yukie Shimizu; Jihun Kwon; Masami Yoneyama; Kohsuke Kudo
  Japanese journal of radiology, 26 Sep. 2025, [Domestic magazines]
  English, Scientific journal, PURPOSE: To evaluate the image quality and clinical utility of ultra-fast T2-weighted imaging (UF-T2WI), which acquires all slice data in 7 s using a single-shot turbo spin-echo technique combined with dual-type deep learning (DL) reconstruction, incorporating DL-based image denoising and super-resolution processing, by comparing UF-T2WI with conventional T2WI. MATERIAL AND METHODS: We analyzed data from 38 patients who underwent both conventional T2WI and UF-T2WI with the dual-type DL-based image reconstruction. Two board-certified radiologists independently performed blinded qualitative assessments of the patients' images obtained with UF-T2WI with DL and conventional T2WI, evaluating the overall image quality, anatomical structure visibility, and levels of noise and artifacts. In cases that included central nervous system diseases, the lesions' delineation was also assessed. The quantitative analysis included measurements of signal-to-noise ratios in white and gray matter and the contrast-to-noise ratio between gray and white matter. RESULTS: Compared to conventional T2WI, UF-T2WI with DL received significantly higher ratings for overall image quality and lower noise and artifact levels (p < 0.001 for both readers). The anatomical visibility was significantly better in UF-T2WI for one reader, with no significant difference for the other reader. The lesion visibility in UF-T2WI was comparable to that in conventional T2WI. Quantitatively, the SNRs and CNRs were all significantly higher in UF-T2WI than conventional T2WI (p < 0.001). CONCLUSION: The combination of SSTSE with dual-type DL reconstruction allows for the acquisition of clinically acceptable T2WI images in just 7 s. This technique shows strong potential to reduce MRI scan times and improve clinical workflow efficiency.
• ビーグル犬OAモデルを用いた17-O標識水造影MRIによる早期軟骨病変の定量評価
  松ヶ崎 圭純; 小野寺 智洋; 宝満 健太郎; 亀田 浩之; 工藤 與亮; 細川 吉暁; 松岡 正剛; 福田 龍一; 坂井 裕子; 劉 越; 岩崎 倫政
  日本整形外科学会雑誌, 99, 8, S1641, S1641, (公社)日本整形外科学会, Sep. 2025
  Japanese
• Dual-type deep learning-based image reconstruction for advanced denoising and super-resolution processing in head and neck T2-weighted imaging.
  Noriyuki Fujima; Yukie Shimizu; Yohei Ikebe; Hiroyuki Kameda; Taisuke Harada; Nayuta Tsushima; Satoshi Kano; Akihiro Homma; Jihun Kwon; Masami Yoneyama; Kohsuke Kudo
  Japanese journal of radiology, 05 Mar. 2025, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, PURPOSE: To assess the utility of dual-type deep learning (DL)-based image reconstruction with DL-based image denoising and super-resolution processing by comparing images reconstructed with the conventional method in head and neck fat-suppressed (Fs) T2-weighted imaging (T2WI). MATERIALS AND METHODS: We retrospectively analyzed the cases of 43 patients who underwent head/neck Fs-T2WI for the assessment of their head and neck lesions. All patients underwent two sets of Fs-T2WI scans with conventional- and DL-based reconstruction. The Fs-T2WI with DL-based reconstruction was acquired based on a 30% reduction of its spatial resolution in both the x- and y-axes with a shortened scan time. Qualitative and quantitative assessments were performed with both the conventional method- and DL-based reconstructions. For the qualitative assessment, we visually evaluated the overall image quality, visibility of anatomical structures, degree of artifact(s), lesion conspicuity, and lesion edge sharpness based on five-point grading. In the quantitative assessment, we measured the signal-to-noise ratio (SNR) of the lesion and the contrast-to-noise ratio (CNR) between the lesion and the adjacent or nearest muscle. RESULTS: In the qualitative analysis, significant differences were observed between the Fs-T2WI with the conventional- and DL-based reconstruction in all of the evaluation items except the degree of the artifact(s) (p < 0.001). In the quantitative analysis, significant differences were observed in the SNR between the Fs-T2WI with conventional- (21.4 ± 14.7) and DL-based reconstructions (26.2 ± 13.5) (p < 0.001). In the CNR assessment, the CNR between the lesion and adjacent or nearest muscle in the DL-based Fs-T2WI (16.8 ± 11.6) was significantly higher than that in the conventional Fs-T2WI (14.2 ± 12.9) (p < 0.001). CONCLUSION: Dual-type DL-based image reconstruction by an effective denoising and super-resolution process successfully provided high image quality in head and neck Fs-T2WI with a shortened scan time compared to the conventional imaging method.
• 小児感音性難聴を来す疾患のピクトリアル・レビュー
  小市 裕太; 清水 幸衣; 原田 太以佑; 中川 純一; 池辺 洋平; 亀田 浩之; 藤間 憲幸; 工藤 與亮
  北海道放射線医学雑誌, 5, 1, 8, (NPO)メディカルイメージラボ, Mar. 2025
  Japanese
• Imaging of 17O-labeled Water Using Fast T2 Mapping with T2-preparation: A Phantom Study
  Hiroyuki Kameda; Yumi Nakada; Yuta Urushibata; Hiroyuki Sugimori; Takaaki Fujii; Naoya Kinota; Daisuke Kato; Minghui Tang; Keita Sakamoto; Kohsuke Kudo
  Magnetic Resonance in Medical Sciences, 24, 2, 269, 275, Japanese Society for Magnetic Resonance in Medicine, 2025, [Peer-reviewed], [Lead author], [Domestic magazines]
  English, Scientific journal, 17O-labeled water is a T2-shortening contrast agent used in proton MRI and is a promising method for visualizing cerebrospinal fluid (CSF) dynamics because it provides long-term tracking of water molecules. However, various external factors reduce the accuracy of 17O-concentration measurements using conventional signal-intensity-based methods. In addition, T2 mapping, which is expected to provide a stable assessment, is generally limited to temporal-spatial resolution. We developed the T2-prepared based on T2 mapping used in cardiac imaging to adapt to long T2 values and tested whether it could accurately measure 17O-concentration in the CSF using a phantom. The results showed that 17O-concentration in a fluid mimicking CSF could be evaluated with an accuracy comparable to conventional T2-mapping (Carr-Purcell-Meiboom-Gill multi-echo spin-echo method). This method allows 17O-imaging with a high temporal resolution and stability in proton MRI. This imaging technique may be promising for visualizing CSF dynamics using 17O-labeled water.
• Loss of aquaporin-4 impairs cerebrospinal fluid solute clearance through cerebrospinal fluid drainage pathways.
  Daisuke Kato; Hiroyuki Kameda; Naoya Kinota; Takaaki Fujii; Bai Xiawei; Zhou Simi; Yoshiki Takai; Simon Chau; Yoshiki Miyasaka; Tomoji Mashimo; Yoichiro Abe; Masato Yasui; Kazuyuki Minowa; Kohsuke Kudo
  Scientific reports, 14, 1, 27982, 27982, 14 Nov. 2024, [Peer-reviewed], [Corresponding author], [International Magazine]
  English, Scientific journal, The aquaporin-4 (AQP4) water channel is essential in neurofluid dynamics. AQP4 loss impairs solute exchange between the cerebrospinal fluid (CSF) and interstitial fluid (ISF). However, whether AQP4 expression affects solute clearance from the CSF space to the extracranial space remains unclear. This study aimed to investigate this using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) following the intrathecal administration of gadolinium-based contrast agents (GBCAs) to AQP4 knockout (KO) rats. AQP4 KO rats showed reduced efflux of intrathecal GBCAs to the extracranial spaces through CSF drainage pathways and increased retention of intrathecal GBCAs in the CSF space compared with the controls. These results suggest that AQP4 loss impairs solute clearance from the CSF space to the extracranial spaces via the CSF drainage pathways. This study revealed a close relationship between AQP4 expression and CSF solute clearance, contributing to a better understanding of the function of AQP4 in neurofluid dynamics.
• Deep learning reconstructionを用いた全脳3DT1強調画像の画質に関する検討
  堀江 達則; 神島 保; 藤間 憲幸; 亀田 浩之; 工藤 與亮
  JART: 日本診療放射線技師会誌, 71, 10, 1134, 1134, (公社)日本診療放射線技師会, Oct. 2024
  Japanese
• Accelerating FLAIR imaging via deep learning reconstruction: potential for evaluating white matter hyperintensities.
  Noriko Nishioka; Yukie Shimizu; Yukio Kaneko; Toru Shirai; Atsuro Suzuki; Tomoki Amemiya; Hisaaki Ochi; Yoshitaka Bito; Masahiro Takizawa; Yohei Ikebe; Hiroyuki Kameda; Taisuke Harada; Noriyuki Fujima; Kohsuke Kudo
  Japanese journal of radiology, 24 Sep. 2024, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, PURPOSE: To evaluate deep learning-reconstructed (DLR)-fluid-attenuated inversion recovery (FLAIR) images generated from undersampled data, compare them with fully sampled and rapidly acquired FLAIR images, and assess their potential for white matter hyperintensity evaluation. MATERIALS AND METHODS: We examined 30 patients with white matter hyperintensities, obtaining fully sampled FLAIR images (standard FLAIR, std-FLAIR). We created accelerated FLAIR (acc-FLAIR) images using one-third of the fully sampled data and applied deep learning to generate DLR-FLAIR images. Three neuroradiologists assessed the quality (amount of noise and gray/white matter contrast) in all three image types. The reproducibility of hyperintensities was evaluated by comparing a subset of 100 hyperintensities in acc-FLAIR and DLR-FLAIR images with those in the std-FLAIR images. Quantitatively, similarities and errors of the entire image and the focused regions on white matter hyperintensities in acc-FLAIR and DLR-FLAIR images were measured against std-FLAIR images using structural similarity index measure (SSIM), regional SSIM, normalized root mean square error (NRMSE), and regional NRMSE values. RESULTS: All three neuroradiologists evaluated DLR-FLAIR as having significantly less noise and higher image quality scores compared with std-FLAIR and acc-FLAIR (p < 0.001). All three neuroradiologists assigned significantly higher frontal lobe gray/white matter visibility scores for DLR-FLAIR than for acc-FLAIR (p < 0.001); two neuroradiologists attributed significantly higher scores for DLR-FLAIR than for std-FLAIR (p < 0.05). Regarding white matter hyperintensities, all three neuroradiologists significantly preferred DLR-FLAIR (p < 0.0001). DLR-FLAIR exhibited higher similarity to std-FLAIR in terms of visibility of the hyperintensities, with 97% of the hyperintensities rated as nearly identical or equivalent. Quantitatively, DLR-FLAIR demonstrated significantly higher SSIM and regional SSIM values than acc-FLAIR, with significantly lower NRMSE and regional NRMSE values (p < 0.0001). CONCLUSIONS: DLR-FLAIR can reduce scan time and generate images of similar quality to std-FLAIR in patients with white matter hyperintensities. Therefore, DLR-FLAIR may serve as an effective method in traditional magnetic resonance imaging protocols.
• High Resolution TOF-MRA Using Compressed Sensing-based Deep Learning Image Reconstruction for the Visualization of Lenticulostriate Arteries: A Preliminary Study.
  Yuya Hirano; Noriyuki Fujima; Hiroyuki Kameda; Kinya Ishizaka; Jihun Kwon; Masami Yoneyama; Kohsuke Kudo
  Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 20 Jul. 2024, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, PURPOSE: To investigate the visibility of the lenticulostriate arteries (LSAs) in time-of-flight (TOF)-MR angiography (MRA) using compressed sensing (CS)-based deep learning (DL) image reconstruction by comparing its image quality with that obtained by the conventional CS algorithm. METHODS: Five healthy volunteers were included. High-resolution TOF-MRA images with the reduction (R)-factor of 1 were acquired as full-sampling data. Images with R-factors of 2, 4, and 6 were then reconstructed using CS-DL and conventional CS (the combination of CS and sensitivity conceding; CS-SENSE) reconstruction, respectively. In the quantitative assessment, the number of visible LSAs (identified by two radiologists), length of each depicted LSA (evaluated by one radiological technologist), and normalized mean squared error (NMSE) value were assessed. In the qualitative assessment, the overall image quality and the visibility of the peripheral LSA were visually evaluated by two radiologists. RESULTS: In the quantitative assessment of the DL-CS images, the number of visible LSAs was significantly higher than those obtained with CS-SENSE in the R-factors of 4 and 6 (Reader 1) and in the R-factor of 6 (Reader 2). The length of the depicted LSAs in the DL-CS images was significantly longer in the R-factor 6 compared to the CS-SENSE result. The NMSE value in CS-DL was significantly lower than in CS-SENSE for R-factors of 4 and 6. In the qualitative assessment of DL-CS images, the overall image quality was significantly higher than that obtained with CS-SENSE in the R-factors 4 and 6 (Reader 1) and in the R-factor 4 (Reader 2). The visibility of the peripheral LSA was significantly higher than that shown by CS-SENSE in all R-factors (Reader 1) and in the R-factors 2 and 4 (Reader 2). CONCLUSION: CS-DL reconstruction demonstrated preserved image quality for the depiction of LSAs compared to the conventional CS-SENSE when the R-factor is elevated.
• 動注モデルラットを用いた17O標識水による脳血管水透過性の評価 初期検討
  亀田 浩之; 小牧 裕司; 安井 正人; 工藤 與亮
  北海道放射線医学雑誌, 4, 1, 6, (NPO)メディカルイメージラボ, Mar. 2024, [Peer-reviewed], [Lead author]
  Japanese
• MELASに類似した脳卒中様発作を生じた神経核内封入体病の1例
  亀田 浩之; 原田 太以佑; 藤間 憲幸; 清水 幸衣; 池辺 洋平; 平田 健司; 矢部 一郎; 工藤 與亮
  北海道放射線医学雑誌, 4, 20, 24, (NPO)メディカルイメージラボ, Mar. 2024, [Peer-reviewed], [Lead author]
  Japanese
• Improved image quality in contrast-enhanced 3D-T1 weighted sequence by compressed sensing-based deep-learning reconstruction for the evaluation of head and neck.
  Noriyuki Fujima; Junichi Nakagawa; Yohei Ikebe; Hiroyuki Kameda; Taisuke Harada; Yukie Shimizu; Nayuta Tsushima; Satoshi Kano; Akihiro Homma; Jihun Kwon; Masami Yoneyama; Kohsuke Kudo
  Magnetic resonance imaging, 108, 111, 115, 09 Feb. 2024, [Peer-reviewed], [International Magazine]
  English, Scientific journal, PURPOSE: To assess the utility of deep learning (DL)-based image reconstruction with the combination of compressed sensing (CS) denoising cycle by comparing images reconstructed by conventional CS-based method without DL in fat-suppressed (Fs)-contrast enhanced (CE) three-dimensional (3D) T1-weighted images (T1WIs) of the head and neck. MATERIALS AND METHODS: We retrospectively analyzed the cases of 39 patients who had undergone head and neck Fs-CE 3D T1WI applying reconstructions based on conventional CS and CS augmented by DL, respectively. In the qualitative assessment, we evaluated overall image quality, visualization of anatomical structures, degree of artifacts, lesion conspicuity, and lesion edge sharpness based on a five-point system. In the quantitative assessment, we calculated the signal-to-noise ratios (SNRs) of the lesion and the posterior neck muscle and the contrast-to-noise ratio (CNR) between the lesion and the adjacent muscle. RESULTS: For all items of the qualitative analysis, significantly higher scores were awarded to images with DL-based reconstruction (p < 0.001). In the quantitative analysis, DL-based reconstruction resulted in significantly higher values for both the SNR of lesions (p < 0.001) and posterior neck muscles (p < 0.001). Significantly higher CNRs were also observed in images with DL-based reconstruction (p < 0.001). CONCLUSION: DL-based image reconstruction integrating into the CS-based denoising cycle offered superior image quality compared to the conventional CS method. This technique will be useful for the assessment of patients with head and neck disease.
• 内耳に造影効果を認めたCogan症候群の1例
  小市 裕太; 池辺 洋平; 藤間 憲幸; 亀田 浩之; 原田 太以佑; 清水 幸衣; 工藤 與亮; 竹崎 俊一郎; 藤原 圭志
  Japanese Journal of Radiology, 42, Suppl., 4, 4, (公社)日本医学放射線学会, Feb. 2024, [Peer-reviewed]
  Japanese
• Automated Detection of Cerebral Microbleeds on Two-dimensional Gradient-recalled Echo T2* Weighted Images Using a Morphology Filter Bank and Convolutional Neural Network
  Noriko Nishioka; Yukie Shimizu; Toru Shirai; Hisaaki Ochi; Yoshitaka Bito; Kiichi Watanabe; Hiroyuki Kameda; Taisuke Harada; Kohsuke Kudo
  Magnetic Resonance in Medical Sciences, Japanese Society for Magnetic Resonance in Medicine, 2024, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, PURPOSE: We present a novel algorithm for the automated detection of cerebral microbleeds (CMBs) on 2D gradient-recalled echo T2* weighted images (T2*WIs). This approach combines a morphology filter bank with a convolutional neural network (CNN) to improve the efficiency of CMB detection. A technical evaluation was performed to ascertain the algorithm's accuracy. METHODS: In this retrospective study, 60 patients with CMBs on T2*WIs were included. The gold standard was set by three neuroradiologists based on the Microbleed Anatomic Rating Scale guidelines. Images with CMBs were extracted from the training dataset comprising 30 cases using a morphology filter bank, and false positives (FPs) were removed based on the threshold of size and signal intensity. The extracted images were used to train the CNN (Vgg16). To determine the effectiveness of the morphology filter bank, the outcomes of the following two methods for detecting CMBs from the 30-case test dataset were compared: (a) employing the morphology filter bank and additional FP removal and (b) comprehensive detection without filters. The trained CNN processed both sets of initial CMB candidates, and the final CMB candidates were compared with the gold standard. The sensitivity and FPs per patient of both methods were compared. RESULTS: After CNN processing, the morphology-filter-bank-based method had a 95.0% sensitivity with 4.37 FPs per patient. In contrast, the comprehensive method had a 97.5% sensitivity with 25.87 FPs per patient. CONCLUSION: Through effective CMB candidate refinement with a morphology filter bank and FP removal with a CNN, we achieved a high CMB detection rate and low FP count. Combining a CNN and morphology filter bank may facilitate the accurate automated detection of CMBs on T2*WIs.
• Magnetic Resonance Water Tracer Imaging Using 17 O-Labeled Water.
  Hiroyuki Kameda; Naoya Kinota; Daisuke Kato; Takaaki Fujii; Taisuke Harada; Yuji Komaki; Hiroyuki Sugimori; Tomohiro Onodera; Moyoko Tomiyasu; Takayuki Obata; Kohsuke Kudo
  Investigative radiology, 59, 1, 92, 103, 01 Jan. 2024, [Peer-reviewed], [Lead author], [International Magazine]
  English, Scientific journal, Magnetic resonance imaging (MRI) is a crucial imaging technique for visualizing water in living organisms. Besides proton MRI, which is widely available and enables direct visualization of intrinsic water distribution and dynamics in various environments, MR-WTI (MR water tracer imaging) using 17 O-labeled water has been developed, benefiting from the many advancements in MRI software and hardware that have substantially improved the signal-to-noise ratio and made possible faster imaging. This cutting-edge technique allows the generation of novel and valuable images for clinical use. This review elucidates the studies related to MRI water tracer techniques centered around 17 O-labeled water, explaining the fundamental principles of imaging and providing clinical application examples. Anticipating continued progress in studies involving isotope-labeled water, this review is expected to contribute to elucidating the pathophysiology of various diseases related to water dynamics abnormalities and establishing novel imaging diagnostic methods for associated diseases.
• Blockage of CSF Outflow in Rats after Deep Cervical Lymph Node Ligation Observed Using Gd-based MR Imaging
  Naoya Kinota; Hiroyuki Kameda; Bai Xiawei; Takaaki Fujii; Daisuke Kato; Bunya Takahashi; Ryo Morita; Daisuke Abo; Ryusei Majima; Hiroshi Ishii; Kazuyuki Minowa; Kohsuke Kudo
  Magnetic Resonance in Medical Sciences, 23, 4, 449, 459, Japanese Society for Magnetic Resonance in Medicine, 2024, [Peer-reviewed], [Corresponding author]
  Scientific journal
• Improvement of image quality in diffusion-weighted imaging with model-based deep learning reconstruction for evaluations of the head and neck.
  Noriyuki Fujima; Junichi Nakagawa; Hiroyuki Kameda; Yohei Ikebe; Taisuke Harada; Yukie Shimizu; Nayuta Tsushima; Satoshi Kano; Akihiro Homma; Jihun Kwon; Masami Yoneyama; Kohsuke Kudo
  Magma (New York, N.Y.), 21 Nov. 2023, [Peer-reviewed], [International Magazine]
  English, Scientific journal, OBJECTIVES: To investigate the utility of deep learning (DL)-based image reconstruction using a model-based approach in head and neck diffusion-weighted imaging (DWI). MATERIALS AND METHODS: We retrospectively analyzed the cases of 41 patients who underwent head/neck DWI. The DWI in 25 patients demonstrated an untreated lesion. We performed qualitative and quantitative assessments in the DWI analyses with both deep learning (DL)- and conventional parallel imaging (PI)-based reconstructions. For the qualitative assessment, we visually evaluated the overall image quality, soft tissue conspicuity, degree of artifact(s), and lesion conspicuity based on a five-point system. In the quantitative assessment, we measured the signal-to-noise ratio (SNR) of the bilateral parotid glands, submandibular gland, the posterior muscle, and the lesion. We then calculated the contrast-to-noise ratio (CNR) between the lesion and the adjacent muscle. RESULTS: Significant differences were observed in the qualitative analysis between the DWI with PI-based and DL-based reconstructions for all of the evaluation items (p < 0.001). In the quantitative analysis, significant differences in the SNR and CNR between the DWI with PI-based and DL-based reconstructions were observed for all of the evaluation items (p = 0.002 ~ p < 0.001). DISCUSSION: DL-based image reconstruction with the model-based technique effectively provided sufficient image quality in head/neck DWI.
• Rapid and Reliable Steatosis Rat Model Shrsp5-Dmcr for Cold Storage Experiment.
  Moto Fukai; Hiroyuki Sugimori; Sodai Sakamoto; Kengo Shibata; Hiroyuki Kameda; Takahisa Ishikawa; Norio Kawamura; Masato Fujiyoshi; Sunao Fujiyoshi; Kohsuke Kudo; Tsuyoshi Shimamura; Akinobu Taketomi
  Transplantation proceedings, 55, 4, 1032, 1035, 10 Apr. 2023, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Interventions for liver grafts with moderate macrovesicular steatosis have been important in enlarging donor pools. Here, we tested a high-fat and cholesterol (HFC) diet to create a steatosis model for cold hepatic preservation and reperfusion experiments. The aim of the present study was to assess the steatosis model's reliability and to show the resulting graft's quality for cold preservation and reperfusion experiment. Male SHRSP5-Dmcr rats were raised with an HFC diet for up to 2 weeks. The fat content was evaluated using magnetic resonance imaging (MRI) proton density fat fraction (PDFF). The nonalcoholic fatty liver disease activity score (NAS) was evaluated after excision. Steatosis created by 2 weeks of HFC diet was subjected to 24-hour cold storage in the University of Wisconsin and the original test solution (new sol.). Grafts were applied to isolated perfused rat livers for simulating reperfusion. The NAS were 2.2 (HFC 5 days), 3.3 (HFC 1 week), and 5.0 (HFC 2 weeks). Ballooning and fibrosis were not observed in any group. An MRI-PDFF showed 0.2 (HFC 0 days), 12.0 (HFC 1 week), and 18.9 (HFC 2 weeks). The NAS and MRI-PDFF values correlated. Many indices in the isolated perfused rat liver experiment tended to improve in the new sol. group but were insufficient. Although the new sol. failed to be effective, it acted at multiple sites under difficult conditions. In conclusion, the HFC diet for 2 weeks in SHRSP5-Dmcr rats, together with MRI-PDFF evaluation, is a reliable method for creating simple steatosis and provides good-quality cold preservation and reperfusion experiments.
• Non-Gaussian model-based diffusion-weighted imaging of oral squamous cell carcinoma: associations with Ki-67 proliferation status.
  Tomoka Shima; Noriyuki Fujima; Shigeru Yamano; Hiroyuki Kameda; Masaaki Suzuka; Akiko Takeuchi; Yurika Kinoshita; Nanami Iwai; Kohsuke Kudo; Kazuyuki Minowa
  Oral radiology, 39, 4, 661, 667, 27 Mar. 2023, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, OBJECTIVES: To investigate possible associations between diffusion-weighted imaging (DWI) parameters derived from a non-Gaussian model fitting and Ki-67 status in patients with oral squamous cell carcinoma (OSCC). METHODS: Twenty-four patients with newly diagnosed OSCC were prospectively recruited. DWI was performed using six b-values (0-2500). The diffusion-related parameters of kurtosis value (K), kurtosis-corrected diffusion coefficient (DK), diffusion heterogeneity (α), distributed diffusion coefficient (DDC), slow diffusion coefficient (Dslow), and apparent diffusion coefficient (ADC) were calculated from four diffusion fitting models. Ki-67 status was categorized as low (Ki-67 percentage score < 20%), middle (20-50%), or high (> 50%). Kruskal-Wallis tests were performed between each non-Gaussian diffusion model parameters and Ki-67 grade. RESULTS: The Kruskal-Wallis tests revealed that multiple parameters (K, ADC, Dk, DDC and Dslow) showed statistically significant differences between the three levels of Ki-67 status (K: p = 0.020, ADC: p = 0.012, Dk: p = 0.027, DDC: p = 0.007 and Dslow: p = 0.026). CONCLUSIONS: Several non-Gaussian diffusion model parameters and ADC values were significantly associated with Ki-67 status and have potential as promising prognostic biomarkers in patients with OSCC.
• The utility of diffusion-weighted T2 mapping for the prediction of histological tumor grade in patients with head and neck squamous cell carcinoma.
  Noriyuki Fujima; Yukie Shimizu; Masami Yoneyama; Junichi Nakagawa; Hiroyuki Kameda; Taisuke Harada; Seijiro Hamada; Takayoshi Suzuki; Nayuta Tsushima; Satoshi Kano; Akihiro Homma; Kohsuke Kudo
  Quantitative imaging in medicine and surgery, 12, 8, 4024, 4032, Aug. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Background: In head and neck cancers, histopathological information is important for the determination of the tumor characteristics and for predicting the prognosis. The aim of this study was to assess the utility of diffusion-weighted T2 (DW-T2) mapping for the evaluation of tumor histological grade in patients with head and neck squamous cell carcinoma (SCC). Methods: The cases of 41 patients with head and neck SCC (21 well/moderately and 17 poorly differentiated SCC) were retrospectively analyzed. All patients received MR scanning using a 3-Tesla MR unit. The conventional T2 value, DW-T2 value, ratio of DW-T2 value to conventional T2 value, and apparent diffusion coefficient (ADC) were calculated using signal information from the DW-T2 mapping sequence with a manually placed region of interest (ROI). Results: ADC values in the poorly differentiated SCC group were significantly lower than those in the moderately/well differentiated SCC group (P<0.05). The ratio of DW-T2 value to conventional T2 value was also significantly different between poorly and moderately/well differentiated SCC groups (P<0.01). Receiver operating characteristic (ROC) curve analysis of ADC values showed a sensitivity of 0.76, specificity of 0.67, positive predictive value (PPV) of 0.62, negative predictive value (NPV) of 0.8, accuracy of 0.71 and area under the curve (AUC) of 0.73, whereas the ROC curve analysis of the ratio of DW-T2 value to conventional T2 value showed a sensitivity of 0.76, specificity of 0.83, PPV of 0.76, NPV of 0.83, accuracy of 0.8 and AUC of 0.82. Conclusions: DW-T2 mapping might be useful as supportive information for the determination of tumor histological grade in patients with head and neck SCC.
• Amide proton transfer imaging for the determination of human papillomavirus status in patients with oropharyngeal squamous cell carcinoma.
  Noriyuki Fujima; Yukie Shimizu; Masami Yoneyama; Junichi Nakagawa; Hiroyuki Kameda; Taisuke Harada; Seijiro Hamada; Takayoshi Suzuki; Nayuta Tsushima; Satoshi Kano; Akihiro Homma; Kohsuke Kudo
  Medicine, 101, 28, e29457, 15 Jul. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal, The aim of this study was to investigate the utility of amide proton transfer (APT) imaging for the determination of human papillomavirus (HPV) status in patients with oropharyngeal squamous cell carcinoma (SCC). Thirty-one patients with oropharyngeal SCC were retrospectively evaluated. All patients underwent amide proton transfer imaging using a 3T magnetic resonance (MR) unit. Patients were divided into HPV-positive and -negative groups depending on the pathological findings in their primary tumor. In APT imaging, the primary tumor was delineated with a polygonal region of interest (ROI). Signal information in the ROI was used to calculate the mean, standard deviation (SD) and coefficient of variant (CV) of the APT signals (APT mean, APT SD, and APT CV, respectively). The value of APT CV in the HPV-positive group (0.43 ± 0.04) was significantly lower than that in the HPV-negative group (0.48 ± 0.04) (P = .01). There was no significant difference in APT mean (P = .82) or APT SD (P = .13) between the HPV-positive and -negative groups. Receiver operating characteristic (ROC) curve analysis of APT CV had a sensitivity of 0.75, specificity of 0.8, positive predictive value of 0.75, negative predictive value of 0.8, accuracy of 0.77 and area under the curve (AUC) of 0.8. The APT signal in the HPV-negative group was considered heterogeneous compared to the HPV-positive group. This information might be useful for the determination of HPV status in patients with oropharyngeal SCC.
• Establishment of a New Qualitative Evaluation Method for Articular Cartilage by Dynamic T2w MRI Using a Novel Contrast Medium as a Water Tracer
  Yoshiaki Hosokawa; Tomohiro Onodera; Kentaro Homan; Jun Yamaguchi; Kohsuke Kudo; Hiroyuki Kameda; Hiroyuki Sugimori; Norimasa Iwasaki
  CARTILAGE, 13, 3, 194760352211115, 194760352211115, Jul. 2022, [Peer-reviewed]
  Scientific journal
• Phase I Randomized Trial of ¹⁷ O ‐Labeled Water: Safety and Feasibility Study of Indirect Proton MRI for the Evaluation of Cerebral Water Dynamics
  Taisuke Harada; Kohsuke Kudo; Hiroyuki Kameda; Ryota Sato; Toru Shirai; Yoshitaka Bito; Noriyuki Fujima; Satonori Tsuneta; Toshifumi Nogawa; Kenichiro Maeda; Hiroshi Hayashi; Makoto Sasaki
  Journal of Magnetic Resonance Imaging, 56, 6, 1874, 1882, Wiley, 30 Apr. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal, BACKGROUND: 17 O-labeled water (PSO17) is a contrast agent developed to measure brain water dynamics and cerebral blood flow. PURPOSE: To evaluate the safety and feasibility of PSO17. STUDY TYPE: Prospective study. SUBJECTS: A total of 12 male healthy volunteers (23.1 ± 1.9 years) were assigned to three groups of four subjects: placebo (normal saline), PSO17 10%, and PSO17 20%. FIELD STRENGTH/SEQUENCE: Dynamic 3D fluid attenuated inversion recovery (FLAIR, fast spin echo with variable refocusing flip angle) scans of the brain were performed with 3-T MRI. ASSESSMENT: Contrast agents were injected 5 minutes after the start of a 10-minute scan. Any symptoms, vital signs, and blood and urine tests were evaluated at five timepoints from preinjection to 4 days after. Blood samples for pharmacokinetic analysis, including half-life (T1/2), maximum fraction (Cmax ), time-to-maximum fraction (Tmax ), and area under the curve (AUC), were collected at 13 timepoints from preinjection to 168 hours after. Regions of interest were set in the cerebral cortex (CC), basal ganglia/thalamus (BG/TM), and white matter (WM), and 17 O concentrations were calculated from signal changes and evaluated using Cmax . STATISTICAL TESTS: All items were compared among the three groups using Tukey-Kramer's honestly significant difference test. Statistical significance was defined as P < 0.5. RESULTS: No safety issues were noted with the intravenous administration of PSO17. The T1/2 was approximately 160 hours, and the AUCs were 1.77 ± 0.10 and 3.75 ± 0.36 in the PSO17 10% and 20% groups, respectively. 17 O fractions calculated from MRI signals were higher in the PSO17 20% group than in the 10% and placebo groups. Significant differences were noted between all pairs of groups in the CC and BG/TM, and between PSO17 20% and both placebo and 10% groups in the WM. DATA CONCLUSION: PSO17 might be considered safe as a contrast medium. Dynamic 3D-FLAIR might detect dose-dependent signal changes and estimate 17 O. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1.
• Quantitative magnetic resonance imaging for evaluating of the cerebrospinal fluid kinetics with 17O-labeled water tracer: A preliminary report.
  Hiroyuki Sugimori; Hiroyuki Kameda; Taisuke Harada; Kinya Ishizaka; Masayoshi Kajiyama; Tasuku Kimura; Niki Udo; Masaaki Matsushima; Azusa Nagai; Masahiro Wakita; Ichiro Kusumi; Ichiro Yabe; Kohsuke Kudo
  Magnetic resonance imaging, 87, 77, 85, Apr. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal, The aim of this study was to evaluate the feasibility of kinetic analysis of cerebrospinal fluid (CSF) using 17O-labeled water tracer. Four subjects (two idiopathic normal pressure hydrocephalus (iNPH) and two possible AD dementia patients) were prospectively included. Injectable formulation of 17O-labeled water containing 10 mol% of H217O (PSO17), was intrathecally administered to the subjects with the lateral decubitus position between the 3rd and 4th lumbar vertebrae. MRI acquisitions were performed in four-time points, before PSO17 administration, 1, 8, and 24 h after PSO17 administration. The 3-dimensional fast spin echo sequence was used. After image registration for all four-time points data, polygonal regions of interest (ROIs) were set in the 14 regions to obtain the signal intensity of CSF. Each signal intensity within the ROI was converted to 17O concentration [%]. The peak concentration at one hour after administration, the slope of concentration changes after PSO17 administration [%/s], and the root mean square error (RMSE) for evaluating the performance of a fitting were calculated. There was no significant difference in peak concentration between the iNPH and AD group. The slope in the AD group (-2.25 ± 1.62 × 10-3 [%/h]) was significantly smaller than in the iNPH group (-1.21 ± 2.31 × 10-3 [%/h]), which suggests the speed of CSF clearance in the iNPH group was slower than AD group. The RMSE indicating the fit to the concentration change in the AD group (4.86 ± 4.74 × 10-3) was also significantly smaller than in the iNPH group (8.64 ± 7.56 × 10-3). The kinetic evaluation of CSF using 17O-labeled water was feasible, and this preliminary study suggests that the differentiation of iNPH and possible AD dementia can be achieved using this method.
• Variations and natural history of primary intraparenchymal lesions associated with neurofibromatosis type 2.
  Yukitomo Ishi; Taisuke Harada; Hiroyuki Kameda; Hiromi Okada; Isao Yokota; Michinari Okamoto; Ryosuke Sawaya; Hiroaki Motegi; Shigeru Yamaguchi; Shunsuke Terasaka; Kohsuke Kudo; Miki Fujimura
  Neuroradiology, 64, 2, 393, 396, 23 Nov. 2021, [Peer-reviewed], [International Magazine]
  English, Scientific journal, The study aimed to investigate the clinical implications and natural history of primary intraparenchymal lesions in patients with neurofibromatosis type 2. Radiological findings of 15 neurofibromatosis type 2 cases were retrospectively collected. Twenty-seven primary intraparenchymal lesions were observed in 7 out of 15 patients (47%). Cortical/subcortical T2 hyperintense lesions and enlarged Virchow-Robin spaces were the most common findings in five and four patients, respectively. During the follow-up period (median 84 months), one new primary intraparenchymal lesion was identified and increased lesions were observed in two cases on contrast-enhanced MRI. Surgical resection was performed in one case pathologically diagnosed with atypical meningioma. Twenty-five other lesions without contrast enhancement presented no apparent growth during follow-up. Although most primary intraparenchymal lesions are benign, a subset of cases would present newly developed or increased lesions on contrast-enhanced MRI. Careful monitoring is necessary for such cases, and pathological confirmation should be considered.
• Extramedullary hematopoiesis of the cranial dura.
  Keito Suto; Junichi Sugita; Daigo Hashimoto; Hiroyuki Kameda; Tomoko Mitsuhashi; Takanori Teshima
  International journal of hematology, 113, 3, 315, 317, Mar. 2021, [Peer-reviewed], [Domestic magazines]
  English
• Detection of impaired cerebrovascular reactivity in patients with chronic cerebral ischemia using whole-brain 7T MRA.
  Ikuko Uwano; Hiroyuki Kameda; Taisuke Harada; Masakazu Kobayashi; Wataru Yanagihara; Kengo Setta; Kuniaki Ogasawara; Kunihiro Yoshioka; Fumio Yamashita; Futoshi Mori; Tsuyoshi Matsuda; Makoto Sasaki
  Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, 29, 9, 105081, 105081, Sep. 2020, [Peer-reviewed], [International Magazine]
  English, Scientific journal, BACKGROUND: Cerebrovascular reactivity (CVR) to acetazolamide (ACZ) on single-photon emission computed tomography (SPECT) can be used to assess the severity of chronic cerebral ischemia; however, this is an invasive method. We examined whether whole-brain magnetic resonance angiography (MRA) at 7T could non-invasively detect impaired CVR in patients with chronic cerebral ischemia by demonstrating the leptomeningeal collaterals (LMCs). METHODS: Fifty-seven patients with symptomatic unilateral cervical stenosis underwent whole-brain time-of-flight MRA at 7T and cerebral perfusion SPECT before/after the ACZ challenge. MRA images were visually assessed based on 6-point grading systems to evaluate the development of LMCs toward the middle cerebral artery (MCA) and antegrade flow of MCA. CVR of the affected side was calculated from the SPECT data. Subsequently, we compared the LMC grades on MRA with CVR on SPECT. RESULTS: CVR was significantly lower in grades ≥ 2 of LMCs than in grades 0-1 (P < 0.05) when applying LMCs from the anterior cerebral artery (ACA) and/or posterior cerebral artery (PCA). These differences were more evident than those in the grading of the antegrade MCA flow. The LMC grades from ACA/PCA readily detected reduced CVR (< 18.4%) with a sensitivity/specificity of 0.79/0.82. CONCLUSION: The development of LMCs on whole-brain MRA at 7T can non-invasively detect reduced CVR with a high sensitivity/specificity in patients with unilateral cervical stenosis.
• Improvement of image quality on low-dose dynamic myocardial perfusion computed tomography with a novel 4-dimensional similarity filter.
  Satonori Tsuneta; Noriko Oyama-Manabe; Hiroyuki Kameda; Taisuke Harada; Fumi Kato; Ewoud J Smit; Mathias Prokop; Kohsuke Kudo
  Medicine, 99, 26, e20804, 26 Jun. 2020, [Peer-reviewed], [International Magazine]
  English, Scientific journal, The aim of this study was to evaluate the effect of a novel 4-dimensional similarity filter (4DSF) on quantitative and qualitative parameters of low-dose dynamic myocardial computed tomography perfusion (CTP) images.In this retrospective study, medical records of 32 patients with suspected or known coronary artery disease who underwent dynamic myocardial CTP at 80 kV were included. The 4DSF reduces noise by averaging voxels that have similar dynamic behavior after adaptive iterative dose reduction 3D (AIDR3D) and deformable image registration were applied. Qualitative (artefact, contour sharpness, and myocardial homogeneity [1 = poor; 2 = intermediate; 3 = good]) and quantitative measurement (standard deviation [SD] and signal-to-noise ratio [SNR]) were compared between the 4DSF and AIDR3D. Contrast-to-noise ratio (CNR) between ischemic and normal remote myocardium was also assessed using myocardial perfusion magnetic resonance imaging as the reference standard in seven patients.The 4DSF was successfully applied to all the images. Improvement in subjective image quality yielded by 4DSF was higher than that yielded by AIDR3D (homogeneity, 1.0 [3 vs 2]; artefact, 1.5 [3 vs 1.5]; P < .001) in all patients. The 4DSF significantly decreased the SD by 59% (AIDR3D vs 4DSF: 33.5 ± 0.4 vs 13.8 ± 0.4, P < .001), increased the SNR by 134% (AIDR3D vs 4DSF: 4.4 ± 0.2 vs 10.3 ± 0.2, P < .001), and increased the CNR by 131% (AIDR3D vs 4DSF: 1.6 ± 0.2 vs 3.7 ± 0.2, P < .001).The 4DSF improved the qualitative and quantitative parameters of low-dose dynamic myocardial CTP images.
• Utility of a diffusion-weighted arterial spin labeling (DW-ASL) technique for evaluating the progression of brain white matter lesions.
  Noriyuki Fujima; Hiroyuki Kameda; Yukie Shimizu; Taisuke Harada; Khin Khin Tha; Masami Yoneyama; Kohsuke Kudo
  Magnetic resonance imaging, 69, 81, 87, Jun. 2020, [Peer-reviewed], [International Magazine]
  English, Scientific journal, PURPOSE: To investigate the utility of diffusion-weighted arterial spin labeling (DW-ASL) for detecting the progression of brain white matter lesions. MATERIALS AND METHODS: A total of 492 regions of interest (ROIs) in 41 patients were prospectively analyzed. DW-ASL was performed using the diffusion gradient prepulse of five b-values (0, 25, 60, 102, and 189) before the ASL readout. We calculated the water exchange rate (Kw) with post-processing using the ASL signal information for each b-value. The cerebral blood flow (CBF) was also calculated using b0 images. Using the signal information in FLAIR (fluid-attenuated inversion recovery) images, we classified the severity of white matter lesions into three grades: non-lesion, moderate, and severe. In addition, the normal Kw level was measured from DW-ASL data of 60 ROIs in five control subjects. The degree of variance of the Kw values (Kw-var) was calculated by squaring the value of the difference between each Kw value and the normal Kw level. All patient's ROIs were divided into non-progressive and progressive white matter lesions by comparing the present FLAIR images with those obtained 2 years before this acquisition. RESULTS: Compared to the non-progressive group, the progressive group had significantly lower CBF, significantly higher severity grades in FLAIR, and significantly greater Kw-var values. In a receiver operator characteristic curve analysis, a high area under the curve (AUC) of 0.89 was obtained with the use of Kw-var. In contrast, the AUCs of 0.59 for CBF and 0.72 for severity grades in FLAIR were obtained. CONCLUSIONS: The DW-ASL technique can be useful to detect the progression of brain white matter lesions. This technique will become a clinical tool for patients with various degrees of white matter lesions.
• Computational Fluid Dynamics Analysis of Lateral Striate Arteries in Acute Ischemic Stroke Using 7T High-resolution Magnetic Resonance Angiography.
  Futoshi Mori; Fujimaro Ishida; Tatsunori Natori; Haruna Miyazawa; Hiroyuki Kameda; Taisuke Harada; Kunihiro Yoshioka; Fumio Yamashita; Ikuko Uwano; Kenji Ito; Makoto Sasaki
  Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, 28, 11, 104339, 104339, Nov. 2019, [Peer-reviewed], [International Magazine]
  English, Scientific journal, BACKGROUND: Infarcts in the lateral striate artery (LSA) territory can be caused by several pathological changes, including lipohyalinosis and microatheroma. However, fluid dynamic effects on these changes remain unknown. Thus, we investigated whether the fluid dynamic metrics of the LSAs were altered in patients with acute ischemic stroke using computational fluid dynamics (CFD) analysis. METHODS: Fifty-one patients with acute ischemic stroke confined in the basal ganglia and/or corona radiata underwent high-resolution magnetic resonance angiography (HR-MRA) at 7T. We performed CFD analyses to obtain indices including the wall shear stress (WSS), WSS gradient (WSSG), and flow velocity (FV) and compared these values between the ipsilesional and contralesional sides in the patients with infarcts in the LSA or non-LSA territories. RESULTS: In patients with LSA-territory infarcts, the WSS, WSSG, and FV values were significantly lower in the ipsilesional LSAs than in the contralesional LSAs (P = .01-.03), while these values in the proximal middle cerebral arteries showed no significant lateralities. In contrast, in patients with non-LSA-territory infarcts, there were no significant lateralities in the metrics between the ipsilesional and contralesional sides. CONCLUSIONS: The CFD analyses using HR-MRA revealed significantly low WSS and WSSG values of the ipsilesional LSAs compared with that of the contralesional side in patients with LSA-territory infarcts, suggesting that fluid dynamic factors of LSAs can be one of the risk factors for LSA-territory infarctions.
• Prediction of Hypoxia in Brain Tumors Using a Multivariate Model Built from MR Imaging and 18F-Fluorodeoxyglucose Accumulation Data.
  Yukie Shimizu; Kohsuke Kudo; Hiroyuki Kameda; Taisuke Harada; Noriyuki Fujima; Takuya Toyonaga; Khin Khin Tha; Hiroki Shirato
  Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 19, 3, 227, 234, 15 Oct. 2019, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, PURPOSE: The aim of this study was to generate a multivariate model using various MRI markers of blood flow and vascular permeability and accumulation of 18F-fluorodeoxyglucose (FDG) to predict the extent of hypoxia in an 18F-fluoromisonidazole (FMISO)-positive region. METHODS: Fifteen patients aged 27-74 years with brain tumors (glioma, n = 13; lymphoma, n = 1; germinoma, n = 1) were included. MRI scans were performed using a 3T scanner, and dynamic contrast-enhanced (DCE) perfusion and arterial spin labeling images were obtained. Ktrans and Vp maps were generated using the DCE images. FDG and FMISO positron emission tomography scans were also obtained. A model for predicting FMISO positivity was generated on a voxel-by-voxel basis by a multivariate logistic regression model using all the MRI parameters with and without FDG. Receiver-operating characteristic curve analysis was used to detect FMISO positivity with multivariate and univariate analysis of each parameter. Cross-validation was performed using the leave-one-out method. RESULTS: The area under the curve (AUC) was highest for the multivariate prediction model with FDG (0.892) followed by the multivariate model without FDG and univariate analysis with FDG and Ktrans (0.844 for all). In cross-validation, the multivariate model with FDG had the highest AUC (0.857 ± 0.08) followed by the multivariate model without FDG (0.834 ± 0.119). CONCLUSION: A multivariate prediction model created using blood flow, vascular permeability, and glycometabolism parameters can predict the extent of hypoxia in FMISO-positive areas in patients with brain tumors.
• Detecting lenticulostriate artery lesions in patients with acute ischemic stroke using high-resolution MRA at 7 T.
  Haruna Miyazawa; Tatsunori Natori; Hiroyuki Kameda; Makoto Sasaki; Hideki Ohba; Shinsuke Narumi; Kohei Ito; Mitsunobu Sato; Takafumi Suzuki; Keisuke Tsuda; Kunihiro Yoshioka; Yasuo Terayama
  International journal of stroke : official journal of the International Stroke Society, 14, 3, 290, 297, Apr. 2019, [Peer-reviewed], [International Magazine]
  English, Scientific journal, BACKGROUND: Recent advances in high-resolution (HR) magnetic resonance angiography (MRA) using ultrahigh-field systems enable direct visualization of the lenticulostriate arteries (LSAs), which had been hardly achieved by conventional MRA. Hence, by using HR-MRA at 7 T, we attempted to assess occlusive changes in the LSAs in patients with LSA territorial infarcts. METHODS: We prospectively examined 34 consecutive patients with acute ischemic stroke in the LSA territory using a 7 T scanner. We measured the lengths of the relevant LSAs on HR-MRA and the diameters/volume of the infarcts and compared these between the patients with/without occlusive changes in the LSAs. RESULTS: On HR-MRA, occlusion of the LSAs was observed in 19 (59%) of 32 patients who were eligible for the analyses. The curved/straight lengths of the LSAs in the patients with LSA occlusion (23.1-31.1/17.8-24.3 mm) were significantly shorter than in those without apparent LSA occlusion (25.8-39.5/24.0-30.4 mm) ( P = 0.027/0.003). The anteroposterior/superoinferior diameters of the infarcts were significantly larger in the occluded-LSA group (14.5-21.4/14.9-22.2 mm) than in the intact-LSA group (10.9-16.8/10.8-16.2 mm) ( P = 0.041/0.011). In addition, the curved lengths of the relevant LSAs showed significant correlations with the superoinferior diameters of the infarcts ( r = 0.38, P = 0.034). CONCLUSION: Occlusive changes in the LSAs were frequently found in patients with acute ischemic stroke within the LSA territory when using HR-MRA at 7 T and were substantially related to superoinferior extension of the infarcts.
• Evaluation of Lenticulostriate Arteries Changes by 7 T Magnetic Resonance Angiography in Type 2 Diabetes.
  Satoshi Yashiro; Hiroyuki Kameda; Ai Chida; Yusuke Todate; Yutaka Hasegawa; Kan Nagasawa; Ikuko Uwano; Makoto Sasaki; Kuniaki Ogasawara; Yasushi Ishigaki
  Journal of atherosclerosis and thrombosis, 25, 10, 1067, 1075, 01 Oct. 2018, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, AIM: Progress in neuroimaging techniques allows us to investigate the microvasculature characteristics including lenticulostriate arteries (LSA), which are closely associated with lacunar infarction. Because ischemic stroke is a more critical health problem in East Asian than in other populations, in order to clarify pathological changes underlying cerebral small vessel disease (SVD), we projected an imaging analysis of LSA using high-resolution brain magnetic resonance imaging (MRI) in middle-aged Japanese subjects with type 2 diabetes. METHODS: Twenty-five subjects with type 2 diabetes and 25 non-diabetic control subjects underwent 7 Tesla (7 T) brain MRI. The prevalences of SVD and LSA structural changes were determined in each group. RESULTS: SVD prevalence did not differ significantly between the type 2 diabetes and control groups. The average numbers of stems, as well as numbers of branches, of LSA were significantly smaller in diabetic subjects than non-diabetic control subjects. The signal intensity of LSA was markedly decreased, indicating reduced blood flow in type 2 diabetes. CONCLUSION: In spite of the prevalence of SVD being similar, structural changes and decreased signal intensity of LSA were highly detected in diabetic subjects compared with non-diabetic controls, suggesting that 7 T MRA enables us to determine LSA impairment prior to the development of SVD. Early detection of LSA impairment allows us earlier interventions aimed at the prevention of atherosclerotic events.
• Indirect Proton MR Imaging and Kinetic Analysis of ¹⁷O-Labeled Water Tracer in the Brain
  Kohsuke Kudo; Taisuke Harada; Hiroyuki Kameda; Ikuko Uwano; Fumio Yamashita; Satomi Higuchi; Kunihiro Yoshioka; Makoto Sasaki
  Magnetic Resonance in Medical Sciences, 17, 3, 223, 230, Japanese Society for Magnetic Resonance in Medicine, 2018, [Peer-reviewed]
  Scientific journal
• Improvement of the repeatability of parallel transmission at 7T using interleaved acquisition in the calibration scan
  Hiroyuki Kameda; Kohsuke Kudo; Tsuyoshi Matsuda; Taisuke Harada; Yuji Iwadate; Ikuko Uwano; Fumio Yamashita; Kunihiro Yoshioka; Makoto Sasaki; Hiroki Shirato
  Journal of Magnetic Resonance Imaging, 48, 1, 94, 101, Wiley, 04 Dec. 2017, [Peer-reviewed], [Lead author]
  Scientific journal, Background
  
  Respiration‐induced phase shift affects B₀/B₁⁺ mapping repeatability in parallel transmission (pTx) calibration for 7T brain MRI, but is improved by breath‐holding (BH). However, BH cannot be applied during long scans.
  
  Purpose
  
  To examine whether interleaved acquisition during calibration scanning could improve pTx repeatability and image homogeneity.
  
  Study Type
  
  Prospective.
  
  Subjects
  
  Nine healthy subjects.
  
  Field Strength/Sequence
  
  7T MRI with a two‐channel RF transmission system was used.
  
  Assessment
  
  Calibration scanning for B₀/B₁⁺ mapping was performed under sequential acquisition/free‐breathing (Seq‐FB), Seq‐BH, and interleaved acquisition/FB (Int‐FB) conditions. The B₀ map was calculated with two echo times, and the B₁⁺ map was obtained using the Bloch‐Siegert method. Actual flip‐angle imaging (AFI) and gradient echo (GRE) imaging were performed using pTx and quadrature‐Tx (qTx). All scans were acquired in five sessions. Repeatability was evaluated using intersession standard deviation (SD) or coefficient of variance (CV), and in‐plane homogeneity was evaluated using in‐plane CV.
  
  Statistical Tests
  
  A paired t‐test with Bonferroni correction for multiple comparisons was used.
  
  Results
  
  The intersession CV/SDs for the B₀/B₁⁺ maps were significantly smaller in Int‐FB than in Seq‐FB (Bonferroni‐corrected P < 0.05 for all). The intersession CVs for the AFI and GRE images were also significantly smaller in Int‐FB, Seq‐BH, and qTx than in Seq‐FB (Bonferroni‐corrected P < 0.05 for all). The in‐plane CVs for the AFI and GRE images in Seq‐FB, Int‐FB, and Seq‐BH were significantly smaller than in qTx (Bonferroni‐corrected P < 0.01 for all).
  
  Data Conclusion
  
  Using interleaved acquisition during calibration scans of pTx for 7T brain MRI improved the repeatability of B₀/B₁⁺ mapping, AFI, and GRE images, without BH.
  
  Level of Evidence: 1
  
  Technical Efficacy Stage 1
  
  J. Magn. Reson. Imaging 2017.
• Indirect MRI of ¹⁷o‐labeled water using steady‐state sequences: Signal simulation and preclinical experiment
  Kohsuke Kudo; Taisuke Harada; Hiroyuki Kameda; Ikuko Uwano; Fumio Yamashita; Satomi Higuchi; Kunihiro Yoshioka; Makoto Sasaki
  Journal of Magnetic Resonance Imaging, 47, 5, 1373, 1379, Wiley, 31 Aug. 2017, [Peer-reviewed]
  Scientific journal, BACKGROUND
  
  Few studies have been reported for T₂‐weighted indirect ¹⁷O imaging.
  
  PURPOSE/HYPOTHESIS
  
  To evaluate the feasibility of steady‐state sequences for indirect ¹⁷O brain imaging.
  
  STUDY TYPE
  
  Signal simulation, phantom measurements, and prospective animal experiments were performed in accordance with the institutional guidelines for animal experiments.
  
  POPULATION/SUBJECTS/PHANTOM/SPECIMEN/ANIMAL MODEL
  
  Signal simulations of balanced steady‐state free precession (bSSFP) were performed for concentrations of ¹⁷O ranging from 0.037–1.600%. Phantom measurements with concentrations of ¹⁷O water ranging from 0.037–1.566% were also conducted. Six healthy beagle dogs were scanned with intravenous administration of 20% ¹⁷O‐labeled water (1 mL/kg).
  
  FIELD STRENGTH/SEQUENCE
  
  Dynamic 3D‐bSSFP scans were performed at 3T MRI. ¹⁷O‐labeled water was injected 60 seconds after the scan start, and the total scan duration was 5 minutes.
  
  ASSESSMENT
  
  Based on the result of signal simulation and phantom measurement, signal changes in the beagle dogs were measured and converted into ¹⁷O concentrations.
  
  STATISTICAL TESTS
  
  The ¹⁷O concentrations were averaged for every 15 seconds, and compared to the baseline (30–45 sec) with Dunnett's multiple comparison tests.
  
  RESULTS
  
  Signal simulation revealed that the relationships between ¹⁷O concentration and the natural logarithm of relative signals were linear. The intraclass correlation coefficient between relative signals in phantom measurement and signal simulations was 0.974. In the animal experiments, significant increases in ¹⁷O concentration (P < 0.05) were observed 60 seconds after the injection of ¹⁷O. At the end of scanning, mean respective ¹⁷O concentrations of 0.084 ± 0.026%, 0.117 ± 0.038, 0.082 ± 0.037%, and 0.049 ± 0.004% were noted for the cerebral cortex, cerebellar cortex, cerebral white matter, and ventricle.
  
  DATA CONCLUSION
  
  Dynamic steady‐state sequences were feasible for indirect ¹⁷O imaging, and absolute quantification was possible. This method can be applied for the measurement of permeability and blood flow in the brain, and for kinetic analysis of cerebrospinal fluid.
  
  Level of Evidence: 2
  
  Technical Efficacy: Stage 1
  
  J. Magn. Reson. Imaging 2018;47:1373–1379.
• Differential diagnosis of parkinsonism by a combined use of diffusion kurtosis imaging and quantitative susceptibility mapping
  Kenji Ito; Chigumi Ohtsuka; Kunihiro Yoshioka; Hiroyuki Kameda; Suguru Yokosawa; Ryota Sato; Yasuo Terayama; Makoto Sasaki
  NEURORADIOLOGY, 59, 8, 759, 769, Aug. 2017, [Peer-reviewed]
  English, Scientific journal
• Noninvasive Assessment of Oxygen Extraction Fraction in Chronic Ischemia Using Quantitative Susceptibility Mapping at 7 Tesla
  Ikuko Uwano; Kohsuke Kudo; Ryota Sato; Kuniaki Ogasawara; Hiroyuki Kameda; Jun-ichi Nomura; Futoshi Mori; Fumio Yamashita; Kenji Ito; Kunihiro Yoshioka; Makoto Sasaki
  STROKE, 48, 8, 2136, 2141, Aug. 2017, [Peer-reviewed]
  English, Scientific journal
• Tmax Determined Using a Bayesian Estimation Deconvolution Algorithm Applied to Bolus Tracking Perfusion Imaging: A Digital Phantom Validation Study
  Ikuko Uwano; Makoto Sasaki; Kohsuke Kudo; Timothe Boutelier; Hiroyuki Kameda; Futoshi Mori; Fumio Yamashita
  MAGNETIC RESONANCE IN MEDICAL SCIENCES, 16, 1, 32, 37, 2017, [Peer-reviewed]
  English, Scientific journal
• Breath-holding during the Calibration Scan Improves the Reproducibility of Parallel Transmission at 7T for Human Brain
  Taisuke Harada; Kohsuke Kudo; Ikuko Uwano; Fumio Yamashita; Hiroyuki Kameda; Tsuyoshi Matsuda; Makoto Sasaki; Hiroki Shirato
  MAGNETIC RESONANCE IN MEDICAL SCIENCES, 16, 1, 23, 31, 2017, [Peer-reviewed]
  English, Scientific journal
• Detection of changes in the ventral tegmental area of patients with schizophrenia using neuromelanin-sensitive MRI.
  Fumio Yamashita; Makoto Sasaki; Kentaro Fukumoto; Kotaro Otsuka; Ikuko Uwano; Hiroyuki Kameda; Jin Endoh; Akio Sakai
  Neuroreport, 27, 5, 289, 94, 23 Mar. 2016, [Peer-reviewed], [International Magazine]
  English, Scientific journal, The ventral tegmental area (VTA), one of the neuromelanin-containing dopaminergic nuclei in the midbrain, is closely related to the pathogenesis of schizophrenia, but its imaging findings remain unclear. Here, we investigated whether neuromelanin-sensitive MRI can detect alterations in the signals of the VTA of patients with schizophrenia. Neuromelanin-sensitive T1-weighted images at 3 T were obtained in 14 patients with schizophrenia and 22 healthy individuals. After signal inhomogeneity correction, brain signal rescaling of the images, and spatial normalization, signal intensity of the VTA and substantia nigra pars compacta (SNc) was automatically measured using the regions-of-interest constructed from the images of the healthy individuals. The normalized signal intensity of the VTA in patients with schizophrenia (median ± quartile deviation, 998 ± 10) was significantly decreased compared with that in healthy controls (1018 ± 15) (P=0.010), whereas that of the SNc was not significantly different between the groups (1093 ± 6 and 1098 ± 10, respectively, P=0.84). The VTA/SNc ratio was also significantly lower in patients with schizophrenia (0.916 ± 0.007) than in the control participants (0.934 ± 0.010) (P=0.010). In addition, the scores of the Scale for the Assessment of Positive Symptoms showed an independent negative correlation with VTA signaling (r=-0.69, P=0.012). Neuromelanin-sensitive MRI enables direct visualization of the selective signal attenuation in the VTA, which was correlated with positive symptoms, in patients with schizophrenia.
• Detection of changes in the periaqueductal gray matter of patients with episodic migraine using quantitative diffusion kurtosis imaging: preliminary findings
  Kenji Ito; Masako Kudo; Makoto Sasaki; Ayumi Saito; Fumio Yamashita; Taisuke Harada; Suguru Yokosawa; Ikuko Uwano; Hiroyuki Kameda; Yasuo Terayama
  NEURORADIOLOGY, 58, 2, 115, 120, Feb. 2016, [Peer-reviewed]
  English, Scientific journal
• Diagnostic value of tumor blood flow and its histogram analysis obtained with pCASL to differentiate sinonasal malignant lymphoma from squamous cell carcinoma
  Noriyuki Fujima; Hiroyuki Kameda; Akiko Tsukahara; Daisuke Yoshida; Tomohiro Sakashita; Akihiro Homma; Khin Khin Tha; Kohsuke Kudo; Hiroki Shirato
  EUROPEAN JOURNAL OF RADIOLOGY, 84, 11, 2187, 2193, Nov. 2015, [Peer-reviewed]
  English, Scientific journal
• TRIM67 Protein Negatively Regulates Ras Activity through Degradation of 80K-H and Induces Neuritogenesis
  Hiroaki Yaguchi; Fumihiko Okumura; Hidehisa Takahashi; Takahiro Kano; Hiroyuki Kameda; Motokazu Uchigashima; Shinya Tanaka; Masahiko Watanabe; Hidenao Sasaki; Shigetsugu Hatakeyama
  JOURNAL OF BIOLOGICAL CHEMISTRY, 287, 15, 12050, 12059, Apr. 2012, [Peer-reviewed]
  English, Scientific journal
• Expression of recombinant sea urchin cellulase SnEG54 using mammalian cell lines
  Fumihiko Okumura; Hiroyuki Kameda; Takao Ojima; Shigetsugu Hatakeyama
  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 395, 3, 352, 355, May 2010, [Peer-reviewed]
  English, Scientific journal
• Inhibition of NF-kappa B signaling via tyrosine phosphorylation of Ymer
  Hiroyuki Kameda; Masashi Watanabe; Miyuki Bohgaki; Tadasuke Tsukiyama; Shigetsugu Hatakeyama
  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 378, 4, 744, 749, Jan. 2009, [Peer-reviewed], [Lead author]
  English, Scientific journal

• 同位体標識水を用いた関節軟骨の水分子動態解析
  松ヶ崎圭純; 小野寺智洋; 宝満健太郎; 亀田浩之; 亀田浩之; 工藤與亮; 坂本直哉; 細川吉暁; 松岡正剛; 福田龍一; 坂井裕子; 岩崎倫政, 日本整形外科学会雑誌(CD-ROM), 99, 3, 2025
• Evaluation of Osteoarthritis in Large Animals Using 17-O Labeled Water MRI: Toward Clinical Application
  松ヶ崎圭純; 小野寺智洋; 宝満健太郎; 亀田浩之; 亀田浩之; 工藤與亮; 細川吉暁; 松岡正剛; 福田龍一; 坂井裕子; LIU Yue; 池翔太; 岩崎倫政, 日本軟骨代謝学会プログラム・抄録集, 37th, 2025
• 同位体顕微鏡による関節軟骨内水動態の組織学的評価
  松ヶ崎 圭純; 小野寺 智洋; 宝満 健太郎; 亀田 浩之; 工藤 與亮; 坂本 直哉; 細川 吉暁; 松岡 正剛; 福田 龍一; 坂井 裕子; 劉 越; 岩崎 倫政, 日本関節病学会誌, 43, 2, 176, 176, Jun. 2024
  (一社)日本関節病学会, Japanese
• 同位体標識水による関節軟骨内水動態の可視化
  松ヶ崎圭純; 小野寺智洋; 宝満健太郎; 細川吉暁; 松岡正剛; 福田龍一; 坂井裕子; 劉越; 岩崎倫政; 亀田浩之; 工藤與亮; 坂本直哉, 北海道整形災害外科学会, 143rd, 2024
• Histological Observation of Water Dynamics in Articular Cartilage Using Isotope Microscopy
  松ヶ崎圭純; 小野寺智洋; 宝満健太郎; 亀田浩之; 亀田浩之; 工藤與亮; 坂本直哉; 細川吉暁; 松岡正剛; 福田龍一; 坂井裕子; 劉越; 岩崎倫政, 日本関節病学会誌(Web), 43, 2, 2024
• 無症候性で診断しえたCarotid webの1例
  池辺洋平; 原田太以佑; 藤間憲幸; 清水幸衣; 亀田浩之; 杉山拓; 工藤與亮, 日本脳神経CI学会総会プログラム・抄録集, 47th, 2024
• ¹⁷O標識水を水トレーサーとして用いたMRIによる関節軟骨の質的評価法の確立
  細川吉暁; 小野寺智洋; 亀田浩之; 宝満健太郎; 工藤與亮; 杉森博行; 岩崎倫政, JOSKAS-JOSSM (Web), 2022, 2022
• 酸素-17安定同位体標識水を水トレーサーとして用いたMRIによる関節軟骨病変評価法の確立
  細川吉暁; 小野寺智洋; 亀田浩之; 宝満健太郎; 山口純; 工藤與亮; 杉森博之; 岩崎倫政, 日本整形外科学会雑誌, 96, 8, 2022
• ¹⁷O標識水を水トレーサーとして用いたMRIによる関節軟骨病変評価法の確立
  細川吉暁; 小野寺智洋; 宝満健太郎; 工藤與亮; 亀田浩之; 杉森博行, 北海道整形災害外科学会, 141st, 2022
• 乳房専用超音波CTにおける高精細音速像の有用性(第2報)
  加藤 扶美; 佐藤 恵美; 西田 睦; 山下 啓子; 竹下 卓志; 萩尾 加奈子; 押野 智博; 亀田 浩之; 常田 慧徳; 堀江 達則; 寺田 崇秀; 坪田 悠史; 川畑 健一; 田中 宏樹; 工藤 與亮, 日本乳癌学会総会プログラム抄録集, 29回, 72, 72, Jul. 2021
  (一社)日本乳癌学会, Japanese
• 乳房専用超音波CTの初期使用経験 高精細音速像の有用性
  加藤 扶美; 山下 啓子; 佐藤 恵美; 西田 睦; 竹下 卓志; 萩尾 加奈子; 押野 智博; 亀田 浩之; 常田 慧徳; 堀江 達則; 寺田 崇秀; 坪田 悠史; 川畑 健一; 工藤 與亮, 日本乳癌学会総会プログラム抄録集, 28回, 144, 144, Oct. 2020
  (一社)日本乳癌学会, Japanese
• Dynamic心筋CT perfusionに対するfour-dimensional similarity filterの画質改善効果の検討
  常田慧徳; 常田慧徳; 真鍋徳子; 亀田浩之; 原田太以佑; 加藤扶美; 工藤與亮, 日本心血管画像動態学会プログラム・抄録集, 30th, 2020
• Dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease)
  星野豊; 亀田浩之; 原田太以佑; 工藤與亮; 伊師雪友; 三橋智子; 杉野弘和, 画像診断, 40, 13, 2020
• 17O標識水の第1相臨床試験 安全性および脳血流MRIの実現可能性に関する検討
  原田 太以佑; 工藤 與亮; 亀田 浩之; 佐藤 良太; 白猪 亨; 尾藤 良孝; 藤間 憲幸; 常田 慧徳; 野川 敏史; 前田 憲一郎; 林 宏至; 佐々木 真理, 日本磁気共鳴医学会雑誌, 39, 2, 66, 66, May 2019
  (一社)日本磁気共鳴医学会, Japanese
• 肝腫瘍術後の肝部下大静脈狭窄に対してステント留置を施行した1例
  亀田 浩之; 阿保 大介; 曽山 武士; 森田 亮; 作原 祐介; 工藤 與亮; 若山 顕治; 蒲池 浩文; 神山 俊哉, IVR: Interventional Radiology, 32, 4, 326, 326, Jan. 2018
  (一社)日本インターベンショナルラジオロジー学会, Japanese
• 超高磁場7-テスラMRIを用いた2型糖尿病患者のレンズ核線条体動脈(LSA)の評価
  八代諭; 亀田浩之; 千田愛; 外舘祐介; 長谷川豊; 長澤幹; 高橋義彦; 武部典子; 小田知靖; 冨樫弘文; 村井智美; 上野育子; 佐々木真理; 小笠原邦昭; 石垣泰, 日本動脈硬化学会総会・学術集会プログラム・抄録集(Web), 49th, 2017
• Amplatzer vascular plug 4(AVP4)を用いた腹腔動脈瘤に対する塞栓術の経験
  木村 輔; 阿保 大介; 亀田 浩之; 高橋 文也; 曽山 武士; 作原 祐介; 工藤 與亮, IVR: Interventional Radiology, 31, 2, 175, 175, Jun. 2016
  (一社)日本インターベンショナルラジオロジー学会, Japanese
• CTが診断に有用であった繰り返す消化管出血症例
  亀田 浩之; 真鍋 徳子; 菊池 穏香; 坂本 圭太; 三村 理恵; 加藤 扶美; 工藤 與亮; 藪崎 哲史; 宮本 憲幸; 西田 睦; 畑中 佳奈子; 大野 正芳; 高橋 典彦, Japanese Journal of Radiology, 34, Suppl., 3, 3, Feb. 2016
  (公社)日本医学放射線学会, Japanese
• MDCTによる膵神経内分泌腫瘍(PNET)の組織学的grade、肝転移に関する検討
  宮本 憲幸; 坂本 圭太; 藪崎 哲史; 亀田 浩之; 豊永 拓哉; 吉野 裕紀; 木村 輔; 菊池 穏香; 三村 理恵; 加藤 扶美; 真鍋 徳子; 工藤 與亮; 土川 貴裕; 中村 透; 岡村 圭祐; 平野 聡, Japanese Journal of Radiology, 34, Suppl., 13, 13, Feb. 2016
  (公社)日本医学放射線学会, Japanese
• 術前MRIによる膵頭部切除後膵液漏発生の検討
  宮本 憲幸; 坂本 圭太; 薮崎 哲史; 高橋 文也; 木村 輔; 亀田 浩之; 菊池 穏香; 三村 理恵; 加藤 扶美; 真鍋 徳子; 工藤 與亮; 白土 博樹; 中村 透; 松本 譲; 岡村 圭祐; 平野 聡, IVR: Interventional Radiology, 30, 3, 271, 271, Sep. 2015
  (一社)日本インターベンショナルラジオロジー学会, Japanese
• 頭頸部における扁平上皮癌と悪性リンパ腫の腫瘍血流の違い
  亀田 浩之; 藤間 憲幸; 吉川 仁人; 吉田 篤司; 清水 幸衣; 吉田 大介; 塚原 亜希子; 工藤 與亮; Tha Khin Khin; 白土 博樹, Japanese Journal of Radiology, 33, Suppl., 1, 1, Feb. 2015
  (公社)日本医学放射線学会, Japanese

• 歯科放射線学
  岡野, 友宏; 全国歯科衛生士教育協議会, 第8章MRI（亀田浩之・箕輪和行）
  医歯薬出版, Jan. 2024, 9784263426357, xi, 117p, Japanese, [Contributor]
• Annual Review神経
  亀田浩之; 工藤 與亮, Basic Neuroscience 画像 酸素の安定同位体17Oによる脳水動態イメージング(解説)
  中外医学社, May 2022, 9784498328822, xi, 331p, Japanese, [Contributor]

• Dynamic Visualization and Quantitative Modeling of Glymphatic Transport Using Intrathecal 17O-Labeled Water MRI in Rats
  Hiroyuki Kameda
  ISMRM Workshop on Fluids, Flows, and Clearance in the Brain: What Can We Image and How Should It Be Interpreted?, 18 Mar. 2026, English, Poster presentation
• 17O標識水髄注とT2prepared併用3D T2マッピングによるヒト髄液動態の可視化の試み
  亀田浩之
  第55回神経放射線学会, 21 Feb. 2026, Poster presentation
• Exploring the Glymphatic Hypothesis with 17O-Labeled Water MRI
  Hiroyuki Kameda
  第55回神経放射線学会, 20 Feb. 2026, English, Nominated symposium
  [Invited]
• 17O標識水の前臨床・臨床研究における開発の歩みと今後の展望
  亀田浩之
  第52回日本磁気共鳴医学会 2024年9月21日, 30 Aug. 2025, Public symposium
  [Invited]
• Imaging of neurofluid dynamics using isotope-labeled water MRI
  Hiroyuki Kameda
  第48回日本神経科学大会, 26 Jul. 2025, English, Public symposium
  24 Jul. 2025 - 27 Jul. 2025, [Invited]
• Visualization of Glymphatic Route on the Rat Cerebral Surface Using Direct Injection of 17O-Labeled Water and Proton MRI
  Hiroyuki Kameda
  Joint Annual Meeting ISMRM-ESMRMB & ISMRT Annual Meeting, 12 May 2025, English
• Visualization of Human CSF Dynamics Using 17O-Labeled Water and Proton MRI
  亀田 浩之
  第84回日本医学放射線学会総会, 10 Apr. 2025
• Neurofluid MR Imaging Using Stable Isotope-Labeled Water
  亀田浩之
  第27回日本ヒト脳マッピング学会, 07 Mar. 2025, English, Nominated symposium
  07 Mar. 2025 - 08 Mar. 2025, [Invited]
• 17O標識水のくも膜下腔直接注入とプロトンＭＲＩによるラット大脳表面の水動態観察
  亀田浩之; 藤井宝顕; 木野田直也; 加藤大祐; 尾藤良孝; 唐明輝; 工藤與亮
  第16回日本水頭症脳脊髄液学会, 10 Nov. 2024
• Visualizing water dynamics on the rat cerebral surface using direct injection of 17O-labeled water into the subarachnoid space and proton MRI
  亀田浩之; 藤井宝顕; 木野田直也; 加藤大祐; 尾藤良孝; 唐明輝; 工藤與亮
  第52回日本磁気共鳴医学会, 21 Sep. 2024
  20 Sep. 2024 - 22 Sep. 2024
• 17O標識水とMRIを用いたneurofluidsの可視化
  第51日本磁気共鳴医学会大会, Nominated symposium
  22 Sep. 2023 - 24 Sep. 2023, [Invited]
• 17O標識水とMRIを用いた髄液循環の可視化
  第53日本神経精神薬理学会年会, Nominated symposium
  07 Sep. 2023 - 09 Sep. 2023, [Invited]
• Neurofluids dynamics by MR imaging
  Hiroyuki Kameda
  the 10th GCB Biomedical Science and Engineering Symposium, 20 Aug. 2023, English, Nominated symposium
  [Invited]
• Visualization of Human Neurofluids Using Intrathecal 17O-Labelled Water and MRI:A Preliminary Study
  Hiroyuki Kameda
  Joint Annual Meeting ISMRM-ESMRMB & ISMRT Annual Meeting, Poster presentation
  03 Jun. 2023 - 08 Jun. 2023
• Increased Vascular Permeability of 17O-labeled Water in the Amyotrophic Lateral Sclerosis Model Mice using Indirect Proton MRI
  Hiroyuki Kameda
  Joint Annual Meeting ISMRM-ESMRMB & ISMRT Annual Meeting, Poster presentation
  07 May 2022 - 12 May 2022
• 17O-Proton MRIによる中枢神経系の水動態イメージングの試み
  亀田浩之
  第44日本脳神経CI学会総会, Nominated symposium
  09 Apr. 2021 - 10 Apr. 2021, [Invited]
• Challenges of glymphatic imaging with 17O-Proton MRI
  Hiroyuki Kameda
  AIMS Neuro Imaging 2020, 24 Oct. 2020, English, Nominated symposium
  [Invited]
• 17O-Proton MR Imaging of Aqua Dynamics in Central Nerve System
  亀田浩之
  第48回日本磁気共鳴医学会大会, Nominated symposium
  11 Sep. 2020 - 13 Sep. 2020, [Invited]
• Detection of Metabolic Water Generated from 17O2 and 17O-Labeled Glucose in Cultured Cells by Indirect Proton MRI
  Hiroyuki Kameda
  ISMRM JPC 2019, Poster presentation
  13 Dec. 2019 - 14 Dec. 2019
• Indirect Proton MRI with 17O-labeled Water Can Detect Blood-Spinal Cord Barrier Abnormalities in the Amyotrophic Lateral Sclerosis Mouse Model
  Hiroyuki Kameda
  ISMRM JPC 2019, Poster presentation
  13 Dec. 2019 - 14 Dec. 2019

• 医学総論, 2024年, 博士後期課程, 医学研究科
• 基本医学総論, 2024年, 修士課程, 医学院
• 基本医学研究, 2024年, 修士課程, 医学院
• 医学総論, 2024年, 博士後期課程, 医学院
• 基盤医学研究, 2024年, 博士後期課程, 医学院
• 発表・論文執筆法演習Ⅰ, 2024年, 博士後期課程, 歯学院
• 発表・論文執筆法演習Ⅱ, 2024年, 博士後期課程, 歯学院
• 発表・論文執筆法演習Ⅲ, 2024年, 博士後期課程, 歯学院
• 口腔画像診断学, 2024年, 博士後期課程, 歯学院
• 口腔病態学実習Ⅰ, 2024年, 博士後期課程, 歯学院
• 口腔病態学実習Ⅱ, 2024年, 博士後期課程, 歯学院
• 口腔病態学実習Ⅲ, 2024年, 博士後期課程, 歯学院
• 口腔病態学実習Ⅳ, 2024年, 博士後期課程, 歯学院
• 口腔病態学実習Ⅴ, 2024年, 博士後期課程, 歯学院
• 放射線治療学研究Ⅰ, 2024年, 博士後期課程, 歯学院
• 放射線治療学研究Ⅱ, 2024年, 博士後期課程, 歯学院
• 放射線生物学研究Ⅰ, 2024年, 博士後期課程, 歯学院
• 放射線生物学研究Ⅱ, 2024年, 博士後期課程, 歯学院
• 歯科放射線学, 2024年, 博士後期課程, 歯学院
• 画像診断学研究Ⅰ, 2024年, 博士後期課程, 歯学院
• 画像診断学研究Ⅱ, 2024年, 博士後期課程, 歯学院
• 歯学研究概論, 2024年, 博士後期課程, 歯学院
• 歯科学概論Ⅱ, 2024年, 学士課程, 歯学部
• 歯科放射線学, 2024年, 学士課程, 歯学部
• 歯科放射線学基礎実習, 2024年, 学士課程, 歯学部
• 歯科放射線学臨床実習Ⅰ, 2024年, 学士課程, 歯学部
• 歯科放射線学臨床実習Ⅱ, 2024年, 学士課程, 歯学部

• 日本インターベンショナルラジオロジー学会
• THE NUCLEAR MAGNETIC RESONANCE SOCIETY OF JAPAN
• JAPANESE SOCIETY FOR MAGNETIC RESONANCE IN MEDICINE
• 日本神経放射線学会
• JAPAN RADIOLOGICAL SOCIETY

• 安定同位体と多核種MRIによる分子イメージング基盤の創出
  革新的医療技術研究開発推進事業（産学官共同型）
  Jan. 2025 - Dec. 2028
  工藤與亮; 亀田浩之; 尾藤良孝; 小川美香子; 小畠隆行; 椛沢宏之; 五島聡; 舟山慧; 久保均
  国立研究開発法人日本医療研究開発機構, 北海道大学, Coinvestigator, 24036104
• ひと・AI/DX・しくみの三位一体的整備による次世代AI活用・データ駆動・情報循環型医学研究の戦略的推進プロジェクト
  医学系研究支援プログラム
  Oct. 2025 - Mar. 2028
  国立研究開発法人日本医療研究開発機構, Coinvestigator
• successful aging-口腔内細菌攻略より
  科学研究費助成事業
  Apr. 2025 - Mar. 2028
  箕輪 和行; 亀田 浩之; 長谷部 晃
  日本学術振興会, 基盤研究(C), 北海道大学, 25K13282
• 脳内水動態解明のためのMRIを用いた移流拡散同時解析法の理論構築と開発
  科学研究費助成事業
  Apr. 2025 - Mar. 2028
  尾藤 良孝; 亀田浩之; 大谷智仁; 工藤與亮
  日本学術振興会, 基盤研究(C), 北海道大学, 25K15857
• 同位体標識水MRIと数理で解き明かす大脳表面の水分子生理・病理
  科学研究費助成事業
  Apr. 2025 - Mar. 2028
  亀田 浩之
  日本学術振興会, 基盤研究(C), 北海道大学, 25K10878
• O-17標識水を水トレーサーとして用いたMRIによる関節軟骨病変の早期診断を可能とする革新的評価法の確立と治験に向けた実用化研究
  橋渡し研究プログラム
  Apr. 2024 - Mar. 2028
  小野寺智洋; 工藤與亮; 亀田浩之; 松岡正剛
  国立研究開発法人日本医療研究開発機構, シーズC(a)（臨床試験に向けた準備・臨床試験を行う課題）, Coinvestigator
• Elucidation of Water Dynamics in the Glymphatic System by Stable Isotope Water Molecule Imaging
  Grants-in-Aid for Scientific Research
  Apr. 2024 - Mar. 2027
  工藤 與亮; 小畠 隆行; 小牧 裕司; 杉森 博行; 亀田 浩之; 安井 正人
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 24K02388
• Proton isotope effect as the method to repair marginal liver graft by extracorporeal perfusion
  Grants-in-Aid for Scientific Research
  01 Apr. 2023 - 31 Mar. 2026
  嶋村 剛; 深井 原; 暮地本 宙己; 亀田 浩之; 西川 祐司; 惠 淑萍
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23K28467
• Proton isotope effect as the method to repair marginal liver graft by extracorporeal perfusion
  Grants-in-Aid for Scientific Research
  01 Apr. 2023 - 31 Mar. 2026
  嶋村 剛; 深井 原; 惠 淑萍; 暮地本 宙己; 亀田 浩之; 西川 祐司
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23H03779
• Exploration of the optimal pH for the graft during cold storage and machine perfusion
  Grants-in-Aid for Scientific Research
  01 Apr. 2023 - 31 Mar. 2026
  深井 原; 暮地本 宙己; 亀田 浩之
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 23K08022
• 歯周病細菌の脳への移行トレース
  科学研究費助成事業
  01 Apr. 2022 - 31 Mar. 2025
  箕輪 和行; 亀田 浩之; 長谷部 晃
  令和4年度は、in vitroで使用する細菌の種類、造影剤の種類や濃度、細菌への造影剤標識方法、MRI撮像用のサンプル作製方法、MRIの撮像方法を検討した。
  使用する細菌の種類としてはPorphyromonas gingivalis（ATCC 33277）、Aggregatibacter actinomycetemcomitans(ATCC 29522)、Streptcoccs mitis(ATCC 9811)を使用した。造影剤の種類および濃度の検討ではGd系としてプリモビスト、マグネビスト、Mn系としてボースデル、Fe系としてリゾビストを使用し、各造影剤を7.7μmol/L、0.77μmol/L、0.077μmol/L、0.0077μmol/Lの濃度で各細菌に使用した。また、細菌への造影剤標識方法の検討では上記の造影剤の条件下で、造影剤と液体培地の混合液での培養、あるいは、ヒートショックを行った。処理後の各サンプルの菌体はホルマリンにて失活・固定した後、複数回洗浄を行い、加温したアガロース溶液で可及的速やかに均一に懸濁した後、プラスチックサンプル管内で硬化させた。各固形サンプルを配列し、その周囲をさらに寒天で充填させ、MRI撮像用のサンプルとした。作製したサンプルを研究用3T-MRI装置で撮像した。撮像シークエンスは、T2 map、T2*map、マルチエコー3D-T1強調像を用いた。Matlab上で、定量的磁化率マッピング画像（QSM画像）を計算し、各条件において定量値に有意な変化があるかどうかを検討した。
  以上の結果より、使用する細菌としてはPorphyromonas gingivalis（ATCC 33277）およびStreptcoccs mitis(ATCC 9811)が妥当であり、使用する造影剤としてはFe系であるリゾビストが妥当であると考えられた。
  日本学術振興会, 基盤研究(C), 北海道大学, 22K10333
• 水と溶質の同位体イメージングによる脳間質の恒常性維持機構の解明
  科学研究費助成事業
  01 Apr. 2022 - 31 Mar. 2025
  亀田 浩之
  T2-preparationパルスを利用した高速T2 mapping法の17O濃度計測における精度を既知のT2 mapping法（CPMG法）と比較したところ、短時間でほぼ同等の精度で17O濃度計測ができることを確認した。野生型ラットに対する17O水髄注モデルでの少数の検討では、有意なT2値変化を検出することができず、脳実質に併せた適切なTEポイントでの計測が必要であり、追加の条件検討が必要であると考えられた。その他、複数の17O水投与経路として、ラットの外頚動脈経由で片側の内頚動脈内に17O水動注を行いながらMRI撮像ができるモデルを確立した。また、脳内水動態異常を簡便に検証するモデルとして、片側頚部リンパ節結紮モデルラットを確立し、Gd髄注MRIを用いた検討で、同モデルは野生型ラットと比較して、鼻腔からの頭蓋内CSFの排泄が遅延することを明らかにした。今後、17O-MRIでの検討を予定している。
  組織レベルでの脳内17O分布をクライオ同位体顕微鏡でみるために、サンプル処理も含めたいくつかの条件検討を行った。脳サンプルは本検討で扱いが難しかったため、18O標識水をラットの肝臓内に注入し、血管内や細胞間隙、細胞内の18O分布のミクロの可視化を試みたところ、肝血管内に一致した18O分布を可視化することができた。しかし、脳サンプルでは肝臓サンプルよりも組織構築が複雑なためか、やや複雑な18O水の分布がどのような組織分布に対応しているのかの推定が難しく、組織情報をもつ対比画像が必要であると考えられた。
  日本学術振興会, 若手研究, 北海道大学, 22K15856
• Multi-scale Imaging of Water Molecules using MRI and Isotope Microscope
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  01 Apr. 2021 - 31 Mar. 2024
  工藤 與亮; 亀田 浩之; 杉森 博行; 村上 正晃; 坂本 直哉; 小牧 裕司; 小畠 隆行; 安井 正人
  ①MRI撮像法開発：O-17標識水の存在によるT2値の短縮を定量的に計測してO-17濃度を定量解析するため、プリパルスを利用した高速T2 mapping法の最適化を行い、精度検証を行った。った。異なる濃度のO-17標識水を含有した濃度ファントムを作成し、高速T2 mapping法と従来のFSE法によるT2 mapping法の精度を比較した。従来法と比較して高精度のT2値測定が可能となったが、低濃度域での精度が十分ではなく、安定性なども改善が必要と考えられた。
  ②正常動物・疾患モデル動物でのMRI撮像：正常マウスやラットにてO-17標識水の静脈内投与や髄腔内投与、頸動脈内投与などを行い、脳脊髄液腔や脳実質のMRI信号変化を確認し、O-17濃度に変換することも可能になった。ALSモデルマウス・ラットにてO-17標識水を静脈内投与、髄腔内投与してMRI撮像を行った。野生型と比較して小脳でのO-17濃度上昇が認められ、臨床研究に応用することが可能になった。
  ③同位体顕微鏡による水分子イメージング：多機能コーティング装置を用いて凍結下での標本作成から同位体顕微鏡によるイメージングまでの解析手順の確認や最適化を行った。
  ④ヒトでのMRI撮像：認知症患者を対象にしたO-17標識水の髄腔内投与研究にて、特発性正常圧水頭症患者とアルツハイマー型認知症患者で研究を継続しており、間接法によるR2変化からの濃度計測に加えて、R2直接計測法も追加して検討を行った。安定性には改善が必要であるが、脳内のO-17濃度変化を捉えることに成功した。
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 21H02857
• 全身主要血管壁内における歯周病原性菌の存在分布ー脳血管障害による死亡例をもとに
  科学研究費助成事業 基盤研究(C)
  01 Apr. 2020 - 31 Mar. 2023
  竹内 明子; 的場 光太郎; 箕輪 和行; 兵頭 秀樹; 亀田 浩之; 長谷部 晃
  ご遺体（法医解剖体）における死後画像取得（CTおよびMRI）により、大血管壁の肥厚・狭窄部の画像的検索を行い、血管プラークを含む主要大血管の血管壁を検体として採取した。これらの検体数は前年よりも5例追加され23例となった。
  採取した検体から血管内皮を剥離し、DNA抽出・リアルタイムPCRにて菌体量を測定した。採取した血管壁のうち、頸動脈、胸部大動脈、腹部大動脈では、血管内皮の剥離は比較的容易であるのに対し、脳血管においては、血管内皮の剥離が困難な場合が多く、またDNA抽出時に十分な組織重量を確保するため、血管内皮を剥離せずに用いることとした。
  胸部大動脈・腹部大動脈では特に血管内皮に石灰化プラークがみられることが多く、血管壁の石灰化部分では、DNA採取（抽出）が困難となる場合があった。このため、判別可能な範囲で石灰化を含まない血管プラークを検体として採取したが、採取した検体に目視困難な微細石灰化が存在することがあり、DNA採取（抽出）の精度が下がる事例があるため、工夫が必要である。個人差があるが、一般には高齢であるほど血管壁の石灰化傾向がみられるため、死後画像（CT画像）にて血管壁の石灰化が認められる症例では、石灰化部を画像ワークステーション上で抽出し、検索・計測を行い、スコア化を検討している。
  また、法医解剖時にご遺体（法医解剖体）の歯科所見を採取し、残存歯数や歯科治療痕等のデータ取得をさらに進めている。さらに、症例増加により調整が必要となっていた残存歯における歯周病進行度のスコアを修正した。さらに、口腔内（歯周ポケット含む）細菌の採取とこれら細菌叢に対してPCRを行い、死後の口腔内細菌叢についての分析・検証を進めている。
  日本学術振興会, 基盤研究(C), 北海道大学, 20K10287
• 酸素の安定同位体O-17標識水による筋萎縮性側索硬化症の早期診断MRI
  難治性疾患等実用化研究事業
  Apr. 2020 - Mar. 2023
  国立研究開発法人日本医療研究開発機構, B.希少難治性疾患に対する画期的な医薬品の実用化に関する研究分野／B-2.医薬品の治験準備（医薬品ステップ１）, 北海道大学 歯学研究院, Coinvestigator, 20314745
• O-17標識水を用いたMRIと同位体顕微鏡による中枢神経系の水動態の解明
  科学研究費助成事業, 若手研究
  Apr. 2019 - Mar. 2021
  亀田 浩之
  17O-MRI間接法による脳脊髄液動態の画像解析法を確立する上で、MRI装置の高い信号感度が必要なことが分かり、特注の小動物用8chコイル(高島製作所)で撮影条件を最適化し、ラットの髄液中に投与した17O水（10mol%, 90mol%）によると考えられる信号変化を脳実質に検出することができた。筋萎縮性側索硬化症（Amyotrophic Lateral Sclerosis, ALS）モデルラットを用いた検討では、ALSラット群で17O水の脳内への移行が速い傾向にあることが分かった。同様の検討を研究協力施設の実験動物中央研究所の小動物用7T-MRIでも行い、同様の結果を確認した。
  組織レベルでの脳内17O分布をクライオ同位体顕微鏡でみるために、18O標識水をラットの脳内に直接注入し分析したところ、常温条件よりも高感度な18O分布を可視化することができた。これには分析面の処理のさらなる工夫が必要であり、本分析における脳の取り扱いがやや難しかったため、肝臓をターゲットとした。ラットのグラフト肝の門脈から18O標識水を注入し、クライオ同位体顕微鏡で観察を行ったところ、肝血管内に一致した18O分布を可視化することができた。ただし、脳においては、17O水や18O水のミクロ分布がどのようなミクロの構造に一致して分布しているのか確認する手段がなく、モデル動物での検証には至らなかった。内因性同位体イメージングによる組織イメージの同時取得や、その他の装置（クライオ電子顕微鏡など）とも連携した解析系の開発が必要であると考えられた。
  日本学術振興会, 若手研究, 北海道大学, Principal investigator, Competitive research funding, 19K17256

• 軟骨の損傷を検出するための造影剤、並びに当該造影剤を利用した軟骨の損傷を検査する方法及びプログラム
  Patent right, 小野寺智洋; 工藤興亮; 細川吉暁; 岩崎倫政; 亀田浩之
  特願2020-180918