Research activity information

• 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, 323, 121599, 121599, 01 Dec. 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.
• Diagnosis of thyroid cartilage invasion by laryngeal and hypopharyngeal cancers based on CT with deep learning.
  Yuki Takano; Noriyuki Fujima; Junichi Nakagawa; Hiroki Dobashi; Yukie Shimizu; Motoma Kanaya; Satoshi Kano; Akihiro Homma; Kohsuke Kudo
  European journal of radiology, 189, 112168, 112168, Aug. 2025, [International Magazine]
  English, Scientific journal, OBJECTIVES: To develop a convolutional neural network (CNN) model to diagnose thyroid cartilage invasion by laryngeal and hypopharyngeal cancers observed on computed tomography (CT) images and evaluate the model's diagnostic performance. METHODS: We retrospectively analyzed 91 cases of laryngeal or hypopharyngeal cancer treated surgically at our hospital during the period April 2010 through May 2023, and we divided the cases into datasets for training (n = 61) and testing (n = 30). We reviewed the CT images and pathological diagnoses in all cases to determine the invasion positive- or negative-status as a ground truth. We trained the new CNN model to classify thyroid cartilage invasion-positive or -negative status from the pre-treatment axial CT images by transfer learning from Residual Network 101 (ResNet101), using the training dataset. We then used the test dataset to evaluate the model's performance. Two radiologists, one with extensive head and neck imaging experience (senior reader) and the other with less experience (junior reader) reviewed the CT images of the test dataset to determine whether thyroid cartilage invasion was present. RESULTS: The following were obtained by the CNN model with the test dataset: area under the curve (AUC), 0.82; 90 % accuracy, 80 % sensitivity, and 95 % specificity. The CNN model showed a significant difference in AUCs compared to the junior reader (p = 0.035) but not the senior reader (p = 0.61). CONCLUSIONS: The CNN-based diagnostic model can be a useful supportive tool for the assessment of thyroid cartilage invasion in patients with laryngeal or hypopharyngeal cancer.
• 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, [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
• 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
  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, [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
  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
  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, [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.
• 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, [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, [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.
• Evaluation of whole-body modalities for diagnosis of multifocal osteonecrosis-a pilot study.
  Shunichi Yokota; Keita Sakamoto; Yukie Shimizu; Tsuyoshi Asano; Daisuke Takahashi; Kohsuke Kudo; Norimasa Iwasaki; Tomohiro Shimizu
  Arthritis research & therapy, 23, 1, 83, 83, 11 Mar. 2021, [International Magazine]
  English, Scientific journal, BACKGROUND: This study aimed to investigate the ability of whole-body bone scintigraphy (WB-BS) in the detection of multifocal osteonecrosis (ON) compared to whole-body magnetic resonance imaging (WB-MRI) and to clarify the characteristics of patients with multifocal ON among those with ON of the femoral head (ONFH) using WB-MRI. METHODS: Forty-six patients who had symptomatic ONFH and underwent surgery in our hospital from April 2019 to October 2020 were included in the study. Data on patient demographics, including age, sex, body mass index (BMI), history of corticosteroid intake, alcohol abuse, smoking, and symptomatic joints, were collected from their medical records. All patients underwent WB-MRI and WB-BS before surgery. RESULTS: The agreement in the detection of ON by WB-MRI vs the uptake lesions by WB-BS in the hip joints was moderate (κ = 0.584), while that in other joints was low (κ < 0.40). Among the 152 joints with ON detected by WB-MRI, 92 joints (60.5%) were symptomatic, and 60 joints (39.5%) were asymptomatic. Twelve out of the 46 (26.0%) patients had multifocal (three or more distinct anatomical sites) ON. Nonetheless, while WB-BS detected symptomatic ON detected by WB-MRI as uptake lesions in 82.6% (76/92) of the joints, asymptomatic ON detected by WB-MRI was detected as uptake lesions in 21.7% (13/60) of the joints. All patients with multifocal ON had a history of steroid therapy, which was significantly higher than that in patients with oligofocal ON (P = 0.035). The patients with a hematologic disease had multifocal ON at a higher rate (P = 0.015). CONCLUSIONS: It might be difficult for WB-BS to detect the asymptomatic ON detected by WB-MRI compared to symptomatic ON. Considering the cost, examination time, and radiation exposure, WB-MRI might be useful for evaluating multifocal ON. Larger longitudinal studies evaluating the benefits of WB-MRI for detecting the risk factors for multifocal ON are required.
• Multiparametric Analysis of Tumor Morphological and Functional MR Parameters Potentially Predicts Local Failure in Pharynx Squamous Cell Carcinoma Patients.
  Noriyuki Fujima; Yukie Shimizu; Daisuke Yoshida; Satoshi Kano; Takatsugu Mizumachi; Akihiro Homma; Koichi Yasuda; Rikiya Onimaru; Osamu Sakai; Kohsuke Kudo; Hiroki Shirato
  The journal of medical investigation : JMI, 68, 3.4, 354, 361, 2021, [Domestic magazines]
  English, Scientific journal, Purpose : To predict local control / failure by a multiparametric approach using magnetic resonance (MR)-derived tumor morphological and functional parameters in pharynx squamous cell carcinoma (SCC) patients. Materials and Methods : Twenty-eight patients with oropharyngeal and hypopharyngeal SCCs were included in this study. Quantitative morphological parameters and intratumoral characteristics on T2-weighted images, tumor blood flow from pseudo-continuous arterial spin labeling, and tumor diffusion parameters of three diffusion models from multi-b-value diffusion-weighted imaging as well as patients' characteristics were analyzed. The patients were divided into local control / failure groups. Univariate and multiparametric analysis were performed for the patient group division. Results : The value of morphological parameter of 'sphericity' and intratumoral characteristic of 'homogeneity' was revealed respectively significant for the prediction of the local control status in univariate analysis. Higher diagnostic performance was obtained with the sensitivity of 0.8, specificity of 0.75, positive predictive value of 0.89, negative predictive value of 0.6 and accuracy of 0.79 by multiparametric diagnostic model compared to results in the univariate analysis. Conclusion : A multiparametric analysis with MR-derived quantitative parameters may be useful to predict local control in pharynx SCC patients. J. Med. Invest. 68 : 354-361, August, 2021.
• 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, 19, 3, 227, 234, Japanese Society for Magnetic Resonance in Medicine, Aug. 2020, [Peer-reviewed], [Lead author], [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.
• 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, [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.
• 【MRI再入門-放射線科医のためのマストアイテム-Part1】頭部MRI:脳腫瘍と脱髄・炎症疾患
  藤間 憲幸; 清水 幸衣; 工藤 與亮
  画像診断, 40, 2, 180, 189, (株)学研メディカル秀潤社, Jan. 2020
  Japanese
• Machine-Learning-Based Prediction of Treatment Outcomes Using MR Imaging-Derived Quantitative Tumor Information in Patients with Sinonasal Squamous Cell Carcinomas: A Preliminary Study.
  Noriyuki Fujima; Yukie Shimizu; Daisuke Yoshida; Satoshi Kano; Takatsugu Mizumachi; Akihiro Homma; Koichi Yasuda; Rikiya Onimaru; Osamu Sakai; Kohsuke Kudo; Hiroki Shirato
  Cancers, 11, 6, 10 Jun. 2019, [International Magazine]
  English, Scientific journal, The purpose of this study was to determine the predictive power for treatment outcome of a machine-learning algorithm combining magnetic resonance imaging (MRI)-derived data in patients with sinonasal squamous cell carcinomas (SCCs). Thirty-six primary lesions in 36 patients were evaluated. Quantitative morphological parameters and intratumoral characteristics from T2-weighted images, tumor perfusion parameters from arterial spin labeling (ASL) and tumor diffusion parameters of five diffusion models from multi-b-value diffusion-weighted imaging (DWI) were obtained. Machine learning by a non-linear support vector machine (SVM) was used to construct the best diagnostic algorithm for the prediction of local control and failure. The diagnostic accuracy was evaluated using a 9-fold cross-validation scheme, dividing patients into training and validation sets. Classification criteria for the division of local control and failure in nine training sets could be constructed with a mean sensitivity of 0.98, specificity of 0.91, positive predictive value (PPV) of 0.94, negative predictive value (NPV) of 0.97, and accuracy of 0.96. The nine validation data sets showed a mean sensitivity of 1.0, specificity of 0.82, PPV of 0.86, NPV of 1.0, and accuracy of 0.92. In conclusion, a machine-learning algorithm using various MR imaging-derived data can be helpful for the prediction of treatment outcomes in patients with sinonasal SCCs.
• Three-dimensional Pseudo-continuous Arterial Spin-labeling Using Turbo-spin Echo with Pseudo-steady State Readout: A Comparison with Other Major Readout Methods.
  Suzuko Aoike; Hiroyuki Sugimori; Noriyuki Fujima; Yuriko Suzuki; Yukie Shimizu; Akira Suwa; Kinya Ishizaka; Kohsuke Kudo
  Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 18, 2, 170, 177, 10 Apr. 2019, [Domestic magazines]
  English, Scientific journal, We evaluated 3D pseudo-continuous arterial spin labeling (pCASL) using turbo spin echo with a pseudo-steady-state (PSS) readout in comparison with the other major readout methods of 3D spiral and 2D echo-planar imaging (EPI). 3D-PSS produced cerebral blood flow (CBF) values well correlated to those of the 3D spiral readout. By visual evaluation, the image quality of 3D-PSS pCASL was superior to that of 2D-EPI. The 3D-PSS technique was suggested useful as pCASL readout.
• The utility of MRI histogram and texture analysis for the prediction of histological diagnosis in head and neck malignancies.
  Noriyuki Fujima; Akihiro Homma; Taisuke Harada; Yukie Shimizu; Khin Khin Tha; Satoshi Kano; Takatsugu Mizumachi; Ruijiang Li; Kohsuke Kudo; Hiroki Shirato
  Cancer imaging : the official publication of the International Cancer Imaging Society, 19, 1, 5, 5, 04 Feb. 2019, [International Magazine]
  English, Scientific journal, BACKGROUND: To assess the utility of histogram and texture analysis of magnetic resonance (MR) fat-suppressed T2-weighted imaging (Fs-T2WI) for the prediction of histological diagnosis of head and neck squamous cell carcinoma (SCC) and malignant lymphoma (ML). METHODS: The cases of 57 patients with SCC (45 well/moderately and 12 poorly differentiated SCC) and 10 patients with ML were retrospectively analyzed. Quantitative parameters with histogram features (relative mean signal, coefficient of variation, kurtosis and skewness) and gray-level co-occurrence matrix (GLCM) features (contrast, correlation, energy and homogeneity) were calculated using Fs-T2WI data with a manual tumor region of interest (ROI). RESULTS: The following significantly different values were obtained for the total SCC versus ML groups: relative mean signal (3.65 ± 0.86 vs. 2.61 ± 0.49), contrast (72.9 ± 16.2 vs. 49.3 ± 8.7) and homogeneity (2.22 ± 0.25 × 10- 1 vs. 2.53 ± 0.12 × 10- 1). In the comparison of the SCC histological grades, the relative mean signal and contrast were significantly lower in the poorly differentiated SCC (2.89 ± 0.63, 56.2 ± 12.9) compared to the well/moderately SCC (3.85 ± 0.81, 77.5 ± 13.9). The homogeneity in poorly differentiated SCC (2.56 ± 0.15 × 10- 1) was higher than that of the well/moderately SCC (2.1 ± 0.18 × 10- 1). CONCLUSIONS: Parameters obtained by histogram and texture analysis of Fs-T2WI may be useful for noninvasive prediction of histological type and grade in head and neck malignancy.
• 特徴的な画像所見を呈した鞍上部immature teratomaの1例
  藤井 宝顕; 原田 太以佑; 清水 幸衣; 藤間 憲幸; Tha Khin Khin; 工藤 與亮; 寺坂 俊介; 長 祐子; 白土 博樹
  Japanese Journal of Radiology, 37, Suppl., 4, 4, (公社)日本医学放射線学会, Feb. 2019
  Japanese
• 血管内治療におけるMRAとCTAによるアクセスルートの比較
  小林 聡; 長内 俊也; 中山 若樹; 鐙谷 武雄; 数又 研; 藤間 憲幸; 清水 幸衣; 大野 浩太; 宝金 清博
  脳血管内治療, 3, Suppl., S268, S268, (NPO)日本脳神経血管内治療学会, Nov. 2018
  Japanese
• 30年後の再発が疑われる脊髄Germinomaの1例
  木野田 直也; 原田 太以佑; 吉田 篤司; 清水 幸衣; 藤間 憲幸; 工藤 興亮; Khin Khin Tha; 白土 博樹; 山口 秀; 小林 浩之; 寺坂 俊介; 岡田 宏美; 畑中 佳奈子
  Japanese Journal of Radiology, 36, Suppl., 3, 3, (公社)日本医学放射線学会, Feb. 2018
  Japanese
• 長期間経過を追えたCerebral Amyloid Angiopathyの1例
  常田 慧徳; 原田 太以佑; 吉田 篤司; 清水 幸衣; 藤間 憲幸; 工藤 與亮; 西村 洋昭; 佐々木 秀直; Khin Khin Tha; 白土 博樹
  Japanese Journal of Radiology, 36, Suppl., 13, 13, (公社)日本医学放射線学会, Feb. 2018
  Japanese
• Non-invasive prediction of the tumor growth rate using advanced diffusion models in head and neck squamous cell carcinoma patients.
  Noriyuki Fujima; Tomohiro Sakashita; Akihiro Homma; Taisuke Harada; Yukie Shimizu; Khin Khin Tha; Kohsuke Kudo; Hiroki Shirato
  Oncotarget, 8, 20, 33631, 33643, 16 May 2017, [International Magazine]
  English, Scientific journal, We assessed parameters of advanced diffusion weighted imaging (DWI) models for the prediction of the tumor growth rate in 55 head and neck squamous cell carcinoma (HNSCC) patients. The DWI acquisition used single-shot spin-echo echo-planar imaging with 12 b-values (0-2000). We calculated 14 DWI parameters using mono-exponential, bi-exponential, tri-exponential, stretched exponential and diffusion kurtosis imaging models. We directly measured the tumor growth rate from two sets of different-date imaging data. We divided the patients into a discovery group (n = 40) and validation group (n = 15) based on their MR acquisition dates. In the discovery group, we performed univariate and multivariate regression analyses to establish the multiple regression equation for the prediction of the tumor growth rate using diffusion parameters. The equation obtained with the discovery group was applied to the validation group for the confirmation of the equation's accuracy. After the univariate and multivariate regression analyses in the discovery-group patients, the estimated tumor growth rate equation was established by using the significant parameters of intermediate diffusion coefficient D2 and slow diffusion coefficient D3 obtained by the tri-exponential model. The discovery group's correlation coefficient between the estimated and directly measured tumor growth rates was 0.74. In the validation group, the correlation coefficient (r = 0.66) and intra-class correlation coefficient (0.65) between the estimated and directly measured tumor growth rates were respectively good. In conclusion, advanced DWI model parameters can be a predictor for determining HNSCC patients' tumor growth rate.
• Prediction of the treatment outcome using intravoxel incoherent motion and diffusional kurtosis imaging in nasal or sinonasal squamous cell carcinoma patients.
  Noriyuki Fujima; Daisuke Yoshida; Tomohiro Sakashita; Akihiro Homma; Akiko Tsukahara; Yukie Shimizu; Khin Khin Tha; Kohsuke Kudo; Hiroki Shirato
  European radiology, 27, 3, 956, 965, Mar. 2017, [International Magazine]
  English, Scientific journal, OBJECTIVES: To evaluate the diagnostic value of intravoxel incoherent motion (IVIM) and diffusional kurtosis imaging (DKI) parameters in nasal or sinonasal squamous cell carcinoma (SCC) patients to determine local control/failure. METHODS: Twenty-eight patients were evaluated. MR acquisition used single-shot spin-echo EPI with 12 b-values. Quantitative parameters (mean value, 25th, 50th and 75th percentiles) of IVIM (perfusion fraction f, pseudo-diffusion coefficient D*, and true-diffusion coefficient D), DKI (kurtosis value K, kurtosis corrected diffusion coefficient Dk) and apparent diffusion coefficient (ADC) were calculated. Parameter values at both the pretreatment and early-treatment period, and the percentage change between these two periods were obtained. RESULTS: Multivariate logistic regression analysis: the percentage changes of D (mean, 25th, 50th, 75th), K (mean, 50th, 75th), Dk (mean, 25th, 50th), and ADC (mean, 25th, 50th) were predictors of local control. ROC curve analysis: the parameter with the highest accuracy = the percentage change of D value with the histogram 25th percentile (0.93 diagnostic accuracy). Multivariate Cox regression analyses: the percentage changes of D (mean, 25th, 50th), K (mean, 50th, 75th), Dk (mean, 25th, 50th) and ADC (mean, 25th, 50th) are predictors. CONCLUSIONS: IVIM and DKI parameters, especially the D-value's histogram 25th percentile, are useful for predicting local control. KEY POINTS: • Noninvasive assessment of treatment outcome in SCC patients was achieved using IVIM/DKI. • Several IVIM and DKI parameters can predict the local control. • Especially, the D-value's histogram 25th percentile has high diagnostic accuracy.
• Advanced diffusion models in head and neck squamous cell carcinoma patients: Goodness of fit, relationships among diffusion parameters and comparison with dynamic contrast-enhanced perfusion.
  Noriyuki Fujima; Tomohiro Sakashita; Akihiro Homma; Yukie Shimizu; Atsushi Yoshida; Taisuke Harada; Khin Khin Tha; Kohsuke Kudo; Hiroki Shirato
  Magnetic resonance imaging, 36, 16, 23, Feb. 2017, [International Magazine]
  English, Scientific journal, PURPOSE: We assessed advanced fitting models of diffusion weighted imaging (DWI) in head/neck squamous cell carcinoma (HNSCC) patients to determine the best goodness of fit and correlations among diffusion parameters. We compared these results with those of dynamic contrast-enhanced (DCE) perfusion parameters. MATERIALS AND METHODS: We retrospectively evaluated 32 HNSCC patients (12 sinonasal, 20 pharynx/oral cavity). The DWI acquisition used single-shot spin-echo echo-planar imaging (EPI) with 12 b-values (0-2000). We calculated 14 DWI parameters using mono-exponential, bi-exponential, and tri-exponential models, stretched exponential model (SEM) and diffusion kurtosis imaging (DKI) models. We compared each model's goodness of fit using the residual sum of squares (RSS), Akaike Information Criterion (AIC) and Bayesian information criterion (BIC) value. We determined the correlation between each pair of DWI parameters and between each DWI parameter and DCE perfusion parameter. RESULTS: The tri-exponential fit's RSS, AIC and BIC values were significantly smaller than those for bi-exponential fit. The RSS, AIC and BIC values of the SEM fit and DKI fit were significantly smaller than mono-exponential model. Significant correlations were observed in 30 pairs (sinonasal cavity) and 31 (sinonasal cavity group) among 91 DWI parameter combinations. Significant correlations were also observed in nine pairs (both sinonasal cavity and pharynx/oral cavity group) among 64 DWI/DCE perfusion parameter pairs, in particular, high positive correlations between the tri-exponential model's intermediate diffusion fraction (f2) and the volume of the extracellular extravascular space per unit volume of tissue (ve) were observed in both patient groups. CONCLUSION: We identified several correlations between DWI parameters by advanced fitting models and correlations between DWI and DCE parameters. These will help determine HNSCC patients' detailed tissue structures.
• 【神経放射線診断-最新情報と読影のピットフォール】MRI Perfusion MRI Arterial spin labeling(ASL)とdynamic susceptibility contrast(DSC)を中心に
  清水 幸衣; 工藤 與亮; 藤間 憲幸
  Clinical Neuroscience, 33, 10, 1125, 1128, (株)中外医学社, Oct. 2015
  Japanese
• 孤発性筋萎縮性側索硬化症における上行性感覚路のDTI解析
  清水 幸衣; 藤間 憲幸; 塚原 亜希子; 工藤 與亮; 矢部 一郎; 廣谷 真; 佐々木 秀直; Tha KhinKhin; 白土 博樹
  Japanese Journal of Radiology, 33, Suppl., 9, 9, (公社)日本医学放射線学会, Feb. 2015
  Japanese
• Isolated posterior fossa involvement in posterior reversible encephalopathy syndrome.
  Yukie Shimizu; Khin Khin Tha; Akihiro Iguchi; Yuko Cho; Atsushi Yoshida; Noriyuki Fujima; Akiko Tsukahara; Hiroki Shirato; Satoshi Terae
  The neuroradiology journal, 26, 5, 514, 9, Oct. 2013, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Posterior reversible encephalopathy syndrome (PRES) is characterized by reversible vasogenic edema affecting the subcortical white matter of bilateral occipital and parietal lobes. We describe a case of isolated posterior fossa involvement of PRES which occurred during remission induction chemotherapy for T-cell acute lymphoblastic leukemia. Both the brainstem and cerebellum were extensively involved, but the supratentorial structures were completely spared. The follow-up magnetic resonance images revealed reversibility of most lesions. The knowledge of atypical radiological features of PRES is essential for prompt diagnosis.

• 血管内治療におけるMRAとCTAによるアクセスルートの比較
  小林 聡; 長内 俊也; 中山 若樹; 鐙谷 武雄; 数又 研; 藤間 憲幸; 清水 幸衣; 大野 浩太; 宝金 清博, 脳血管内治療, 3, Suppl., S268, S268, Nov. 2018
  (NPO)日本脳神経血管内治療学会, Japanese

• 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
• 医学総論, 2024年, 博士後期課程, 医学院
• 臨床医学研究, 2024年, 博士後期課程, 医学院

• 脳MRI画像を用いた女性アスリート障害早期診断に向けたバイオマーカー探索
  科学研究費助成事業
  01 Apr. 2022 - 31 Mar. 2025
  清水 幸衣
  日本学術振興会, 若手研究, 北海道大学, 22K15837
• Female athlete triad: elucidation of pathophysiology and search for biomarkers
  Grants-in-Aid for Scientific Research
  11 Sep. 2020 - 31 Mar. 2022
  Shimizu Yukie
  In this study, we've been trying to assess very small area of the hypothalamus-pituitary gland system, which makes it challenging to define the boundery of the area and evaluate its size and propertyies. Therefore, we first needed to arrange the appropriate MRI parameters on healthy controles. We could finally establish the right condition for our study.
  At the end of the last year, two female athlete patients and eight healthy female athletes were included and we obtained their data of brain MRI, bone density, body composition, blood test including hormones and bone metabolism makers, and nutrition.
  Japan Society for the Promotion of Science, Grant-in-Aid for Research Activity Start-up, Hokkaido University, 20K23282