A novel minimization technique was developed. The proposed method is based on a Gaussian random search in the parameter space and it can handle a wide range of problems, including bi-exponential curve fitting, in a reasonable time. It uses only function values, and does not require gradients.
{"title":"Adaptive Gaussian Search : A Novel Non-linear Minimization Technique [Presidential Award Proceedings]","authors":"Koichi OSHIO","doi":"10.2463/jjmrm.2022-1775","DOIUrl":"https://doi.org/10.2463/jjmrm.2022-1775","url":null,"abstract":"A novel minimization technique was developed. The proposed method is based on a Gaussian random search in the parameter space and it can handle a wide range of problems, including bi-exponential curve fitting, in a reasonable time. It uses only function values, and does not require gradients.","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we combined TI dependent optimized reconstruction (TIDOR) with Variable TI UTE 4D-MRA and demonstrated the clinical usefulness of this combined method. Previously, we reported that the late phase vessel visibility of ASL based UTE 4D-MRA was improved by the Variable TI method, which has the extended TI in a manner of progression of difference to keep labeled magnetization away from saturation in late phases5). For further improvement of peripheral vessel visibility, we developed the TIDOR, which takes into account the signal and noise level of each phase. Combining Variable TI UTE 4D-MRA with TIDOR improved the peripheral vessel visibility, especially in the late phases. We demonstrated that this method is effective for clinical applications.
{"title":"Variable TI UTE 4D-MRAへのTIDOR（TI依存型画像再構成最適化法）の適応による脳末梢血管描出能の改善［大会長賞記録］","authors":"Haruyuki FUKUCHI, Toshiya AKATSU, Hiroshi KUSAHARA, Nao TAKANO, Yutaka IKENOUCHI, Michimasa SUZUKI, Koji KAMAGATA, Osamu ABE, Shigeki AOKI","doi":"10.2463/jjmrm.2023-1786","DOIUrl":"https://doi.org/10.2463/jjmrm.2023-1786","url":null,"abstract":"In this study, we combined TI dependent optimized reconstruction (TIDOR) with Variable TI UTE 4D-MRA and demonstrated the clinical usefulness of this combined method. Previously, we reported that the late phase vessel visibility of ASL based UTE 4D-MRA was improved by the Variable TI method, which has the extended TI in a manner of progression of difference to keep labeled magnetization away from saturation in late phases5). For further improvement of peripheral vessel visibility, we developed the TIDOR, which takes into account the signal and noise level of each phase. Combining Variable TI UTE 4D-MRA with TIDOR improved the peripheral vessel visibility, especially in the late phases. We demonstrated that this method is effective for clinical applications.","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transcranial MR-guided focused ultrasound surgery (TcMRgFUS) is recognized as a minimally invasive treatment method for essential tremor (ET), a condition characterized by involuntary motor disturbances. The target region for treating ET is the ventral intermediate (Vim) nucleus of the thalamus, which is surrounded by the ventral caudal nuclei (Vc) and the pyramidal tract (PT).
{"title":"経頭蓋MRガイド下集束超音波治療（transcranial MR-guided focused ultrasound surgery：TcMRgFUS）へのfiber tractography解析の応用","authors":"Hiroki HORI, Tomokatsu HORI, Takaomi TAIRA","doi":"10.2463/jjmrm.2023-1798","DOIUrl":"https://doi.org/10.2463/jjmrm.2023-1798","url":null,"abstract":"Transcranial MR-guided focused ultrasound surgery (TcMRgFUS) is recognized as a minimally invasive treatment method for essential tremor (ET), a condition characterized by involuntary motor disturbances. The target region for treating ET is the ventral intermediate (Vim) nucleus of the thalamus, which is surrounded by the ventral caudal nuclei (Vc) and the pyramidal tract (PT).","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"238 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135402372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent studies have reported an increase in the incidence of lower extremity arterial disease in Japan secondary to rapid population aging and an increase in the numbers of diabetes and dialysis cases. Although widely used, the long-term outcomes of endovascular therapy (EVT) remain unclear. Regular evaluation to monitor restenosis is extremely important. Magnetic resonance angiography is a non-invasive approach to evaluate lower extremity arteries without contrast enhancement or radiation exposure. However, stent lumens present challenges for evaluation in some cases secondary to magnetic susceptibility artifacts. Previous studies have reported the usefulness of the volume isotropic turbo spin-echo (T1 VISTA) method, which is based on three-dimensional variable refocusing flip angle turbo spin echo images for in-stent evaluation after carotid artery stenting. In this study, we describe our findings in two patients in whom the T1 VISTA method was useful to evaluate leg artery stent patency following EVT.
{"title":"Assessment of Lower Limb Artery Stent Placement with 3D Variable Refocusing Flip Angle Turbo Spin Echo : A Report on Two Cases","authors":"Yuki SHIMADA, Michiaki HIGASHITANI, Junichi HASHIMOTO, Akio TSUMURAYA","doi":"10.2463/jjmrm.2023-1785","DOIUrl":"https://doi.org/10.2463/jjmrm.2023-1785","url":null,"abstract":"Recent studies have reported an increase in the incidence of lower extremity arterial disease in Japan secondary to rapid population aging and an increase in the numbers of diabetes and dialysis cases. Although widely used, the long-term outcomes of endovascular therapy (EVT) remain unclear. Regular evaluation to monitor restenosis is extremely important. Magnetic resonance angiography is a non-invasive approach to evaluate lower extremity arteries without contrast enhancement or radiation exposure. However, stent lumens present challenges for evaluation in some cases secondary to magnetic susceptibility artifacts. Previous studies have reported the usefulness of the volume isotropic turbo spin-echo (T1 VISTA) method, which is based on three-dimensional variable refocusing flip angle turbo spin echo images for in-stent evaluation after carotid artery stenting. In this study, we describe our findings in two patients in whom the T1 VISTA method was useful to evaluate leg artery stent patency following EVT.","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135600393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In 2022, a follow-up survey was conducted to the National Survey on Safety Management of MRI Examinations carried out in 2018. This study aimed to compare the two surveys to determine how the “Guidelines for the Safe Operation of Clinical MRI” affect the safe management of MRI examinations in clinical practice, and to identify factors associated with incidents affecting patient health. Automated machine learning was used to identify factors associated with major incidents. Of the 5,816 medical facilities we approached, 2,668 (45.9%) provided full or partial responses, with 2,582 (44.4%) valid responses. Although the number of facilities that participated in the survey and provided valid responses had increased by 567 from the previous survey, the response to safety management varied again in this survey. On the other hand, improvement was seen on most items related to safety management and MRI exam operations. Between October 2020 and September 2021, 242 major incidents occurred at 166 facilities (6%), a 1% increase from 2018. Most of these were related to contrast administration. Minor incidents also increased by 5% (2,068 incidents) at 833 facilities (32%). The largest contributor to the increase in major incidents was the number of examinations per month. Although there was wide variation in the safety standards applied by Japanese facilities performing clinical MRI examinations, facility responses improved for most items related to the safe management and operation of MRI scans.
{"title":"MRI検査の安全管理に対する全国多施設フォローアップ調査研究","authors":"Minako AZUMA, Tsukasa DOI, Mitsuyuki TAKAHASHI, Hirofumi HATA, Tsuyoshi UEYAMA, Junji TAKAHASHI, Kazuyuki SAKAI, Noriko OYAMA-MANABE, Junichi HATA, Masako KATAOKA, Kagayaki KURODA, Shinpei IJICHI, Shigeki AOKI, Toshinori HIRAI","doi":"10.2463/jjmrm.2023-1792","DOIUrl":"https://doi.org/10.2463/jjmrm.2023-1792","url":null,"abstract":"In 2022, a follow-up survey was conducted to the National Survey on Safety Management of MRI Examinations carried out in 2018. This study aimed to compare the two surveys to determine how the “Guidelines for the Safe Operation of Clinical MRI” affect the safe management of MRI examinations in clinical practice, and to identify factors associated with incidents affecting patient health. Automated machine learning was used to identify factors associated with major incidents. Of the 5,816 medical facilities we approached, 2,668 (45.9%) provided full or partial responses, with 2,582 (44.4%) valid responses. Although the number of facilities that participated in the survey and provided valid responses had increased by 567 from the previous survey, the response to safety management varied again in this survey. On the other hand, improvement was seen on most items related to safety management and MRI exam operations. Between October 2020 and September 2021, 242 major incidents occurred at 166 facilities (6%), a 1% increase from 2018. Most of these were related to contrast administration. Minor incidents also increased by 5% (2,068 incidents) at 833 facilities (32%). The largest contributor to the increase in major incidents was the number of examinations per month. Although there was wide variation in the safety standards applied by Japanese facilities performing clinical MRI examinations, facility responses improved for most items related to the safe management and operation of MRI scans.","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"233 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135560584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Golden Angle Radial Sparse Parallel-Volumetric Interpolated Breath hold Examination (GRASP-VIBE) using compressed sensing and golden-angle radial sampling is a gradient echo (GRE) sequence that provides an inflow effect. The purpose of this study was to investigate parameters for non-contrast visualization of the renal artery using GRASP-VIBE with respiratory synchronization by the liver gate. We used a flow phantom and a self-made phantom to determine effective fat suppression methods and appropriate settings for repetition time (TR) and flip angle (FA). We also performed imaging on five healthy volunteers and compared the ability to visualize the renal artery. In the phantom study, water excitation showed the highest fat suppression effect ; the flow phantom was well visualized at TR 7.2 ms～9.0 ms and FA 9°～13°. In the volunteer study, the renal artery was best visualized at TR 7.2 ms and FA 13°. The results suggest that GRASP-VIBE can be used to visualize the renal artery without contrast enhancement by using the parameter settings examined in this study.
{"title":"GRASP-VIBEを用いた非造影腎動脈MRAの試み 至適撮像条件の検討","authors":"Kazuyuki ITO, Nozomi HAMASAKI, Kazuhiko DORYO, Yutaka OZAKI","doi":"10.2463/jjmrm.2023-1793","DOIUrl":"https://doi.org/10.2463/jjmrm.2023-1793","url":null,"abstract":"Golden Angle Radial Sparse Parallel-Volumetric Interpolated Breath hold Examination (GRASP-VIBE) using compressed sensing and golden-angle radial sampling is a gradient echo (GRE) sequence that provides an inflow effect. The purpose of this study was to investigate parameters for non-contrast visualization of the renal artery using GRASP-VIBE with respiratory synchronization by the liver gate. We used a flow phantom and a self-made phantom to determine effective fat suppression methods and appropriate settings for repetition time (TR) and flip angle (FA). We also performed imaging on five healthy volunteers and compared the ability to visualize the renal artery. In the phantom study, water excitation showed the highest fat suppression effect ; the flow phantom was well visualized at TR 7.2 ms～9.0 ms and FA 9°～13°. In the volunteer study, the renal artery was best visualized at TR 7.2 ms and FA 13°. The results suggest that GRASP-VIBE can be used to visualize the renal artery without contrast enhancement by using the parameter settings examined in this study.","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135159910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kumi OZAKI, Satoshi FUNAYAMA, Yukichi TANAHASHI, Shintaro ICHIKAWA, Satoshi GOSHIMA
Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid is a hepatobiliary-specific contrast agent used for enhanced magnetic resonance imaging (EOB-MRI). It can provide specific information on hepatobiliary phase images. In addition to dynamic contrast studies, it is excellent for the detection and characterization of liver lesions.
{"title":"The Impact of Gd-EOB-DTPA Contrast-enhanced MR Imaging on the Diagnosis of Benign Neoplastic and Non-neoplastic Liver Lesions","authors":"Kumi OZAKI, Satoshi FUNAYAMA, Yukichi TANAHASHI, Shintaro ICHIKAWA, Satoshi GOSHIMA","doi":"10.2463/jjmrm.2023-1801","DOIUrl":"https://doi.org/10.2463/jjmrm.2023-1801","url":null,"abstract":"Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid is a hepatobiliary-specific contrast agent used for enhanced magnetic resonance imaging (EOB-MRI). It can provide specific information on hepatobiliary phase images. In addition to dynamic contrast studies, it is excellent for the detection and characterization of liver lesions.","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"180 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135705460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New techniques for high-resolution diffusion-weighted imaging (DWI) have emerged, including reduced field-of-view DWI (rFOV-DWI) and multiplexed sensitivity encoding DWI (MUSE-DWI). These advanced technologies address the limitations of conventional DWI by reducing distortion and providing higher spatial resolution. Particularly, DWI is now a crucial imaging tool in gynecology for diagnosing endometrial and cervical cancer. This article offers an overview of the principles and clinical applications of rFOV-DWI and MUSE-DWI for endometrial and cervical cancer in gynecology.
{"title":"High-resolution Diffusion-weighted Imaging for the Diagnosis of Endometrial and Cervical Cancer","authors":"Takashi OTA, Takahiro TSUBOYAMA, Hiromitsu ONISHI, Atsushi NAKAMOTO, Tetsuya WAKAYAMA, Hideyuki FUKUI, Keigo YANO, Toru HONDA, Kengo KISO, Mitsuaki TATSUMI, Noriyuki TOMIYAMA","doi":"10.2463/jjmrm.2023-1799","DOIUrl":"https://doi.org/10.2463/jjmrm.2023-1799","url":null,"abstract":"New techniques for high-resolution diffusion-weighted imaging (DWI) have emerged, including reduced field-of-view DWI (rFOV-DWI) and multiplexed sensitivity encoding DWI (MUSE-DWI). These advanced technologies address the limitations of conventional DWI by reducing distortion and providing higher spatial resolution. Particularly, DWI is now a crucial imaging tool in gynecology for diagnosing endometrial and cervical cancer. This article offers an overview of the principles and clinical applications of rFOV-DWI and MUSE-DWI for endometrial and cervical cancer in gynecology.","PeriodicalId":471579,"journal":{"name":"Nihon Jiki Kyōmei Igakkai zasshi","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135549471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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