Search Results 1-20 of 41

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  • Evaluation of head motion effects in the processing of multi-echo magnetic resonance imaging data

    SUNG Yul-Wan , KAWACHI Yousuke , OGAWA Seiji

    … Multi-echo planar imaging is an magnetic resonance imaging (MRI) sequence with which MRI images can be acquired at different echo-times after excitation. … This sequences is applied to functional MRI (fMRI) for the removal of non-functional signal artifacts. … Multi-echo planar imaging can be problematic due to artifacts caused by magnetic susceptibility in the boundary regions between the brain tissues and other brain compartments. …

    感性福祉研究所年報 = Report of Kansei Fukushi Research Institute (21), 65-69, 2020-03


  • Influence of magnetic susceptibility and volume on MRI artifacts produced by low magnetic susceptibility Zr-14Nb alloy and dental alloys

    KAJIMA Yuka , TAKAICHI Atsushi , TSUTSUMI Yusuke , HANAWA Takao , WAKABAYASHI Noriyuki , KAWASAKI Akira

    … <p>The artifact volume generated in magnetic resonance (MR) images was quantitatively evaluated to investigate how artifact behavior correlates to the magnetic susceptibility and volume of an implanted metal device. … For this, a new low-magnetic-susceptibility Zr-14Nb alloy was compared with two conventional dental alloys, Ti-6Al-7Nb alloy and Co-Cr-Mo alloy, using spherical specimens of each alloy prepared with four different diameters. …

    Dental Materials Journal 39(2), 256-261, 2020


  • Vacuum Phenomenon of the Knee Joint: Its Prevalence and Diagnostic Pitfall [Presidential Award Proceedings]  [in Japanese]

    AKIYAMA Shimpei , NITTSU Mamoru , MATSUO Shuya , NOZAKI Taiki , YAMADA Kei

    … Gradient-echo imaging facilitated the delineation of minute VP within the joint space with susceptibility artifacts.</p> …

    Japanese Journal of Magnetic Resonance in Medicine 40(1), 30-32, 2020


  • Comparison of Influence of Susceptibility Artifact due to Metallic Embolic Material in MRA Image  [in Japanese]

    Ayabe Yusuke , Hamamoto Kohei , Ikeda Yoshimasa , Koyama Yoshimasa

    … <p><i>Purpose</i>: To identify the influence of susceptibility artifact caused by commonly used trans-catheter embolic devices for vascular lesions in the body on the images of various magnetic resonance angiography (MRA) techniques as an aid to patient screening after endovascular embolization. …

    Japanese Journal of Radiological Technology 75(5), 460-467, 2019

    J-STAGE  Ichushi Web 

  • Imaging Parameter Optimization of 3D Phase Contrast-MRA to Reduce Susceptibility-artifact and Radiofrequency-shielding around the Intracranial Stent  [in Japanese]

    Kiriki Masato , Jomoto Wataru , Ikeda Takashi , Kotoura Noriko

    … <p>The purpose of this study was to evaluate the degree of signal attenuation generated around the stent by the susceptibility artifacts and radiofrequency (RF) shielding in phase contrast-magnetic resonance angiography (PCA) images and construct optimal PCA imaging parameters for intracranial stent lumen images. …

    Japanese Journal of Radiological Technology 74(11), 1293-1301, 2018

    J-STAGE  Ichushi Web 

  • Reducing MRI artifacts induced by SPIONs

    Liu Shuang , Qiu Wenqi , Kuwahata Akihiro , Chikaki Shinichi , Lane Laura , Montalba Cristian , Kusakabe Moriaki , Irarrazaval Pablo , Sekino Masaki

    … However, due to too much SPIONs accumulated in the injection position, a large susceptibility artifact arises in the Magnetic Resonance Imaging(MRI), causing information around the injection position cannot be acquired. …

    Transactions of Japanese Society for Medical and Biological Engineering Annual56(Abstract), S382-S382, 2018


  • Recent advances in magnetic resonance neuroimaging of lumbar nerve to clinical applications: A review of clinical studies utilizing Dffusion Tensor Imaging and Diffusion-weighted magnetic resonance neurography

    Eguchi Yawara , Suzuki Miyako , Inage Kazuhide , Aoki Yasuchika , Watanabe Atsuya , Furuya Takeo , Koda Masao , Takahashi Kazuhisa , Ohtori Seiji , Kanamoto Hirohito , Oikawa Yasuhiro , Suzuki Munetaka , Yamanaka Hajime , Tamai Hiroshi , Kobayashi Tatsuya , Orita Sumihisa , Yamauchi Kazuyo

    … <p>Much progress has been made in neuroimaging with Magnetic Resonance neurography and Diffusion Tensor Imaging (DTI) owing to higher magnetic fields and improvements in pulse sequence technology. … However, increased motion artifacts in the magnetic susceptibility effect lead to signal irregularities and image distortion. …

    Spine Surgery and Related Research 1(2), 61-71, 2017

    J-STAGE  Ichushi Web 

  • Quantitative Susceptibility Mapping Using the Multiple Dipole-inversion Combination with k-space Segmentation Method

    Sato Ryota , Shirai Toru , Taniguchi Yo , Murase Takenori , Bito Yoshitaka , Ochi Hisaaki

    … <p>Quantitative susceptibility mapping (QSM) is a new magnetic resonance imaging (MRI) technique for noninvasively estimating the magnetic susceptibility of biological tissue. … One of these methods can estimate susceptibility with high accuracy in tissues whose contrast is consistent between magnitude images and susceptibility maps, such as deep gray-matter nuclei. …

    Magnetic Resonance in Medical Sciences 16(4), 340-350, 2017

    J-STAGE  Ichushi Web 

  • A-22 The evaluation of artifact from Zr-14Nb alloy with low magnetic susceptibility and traditional dental alloy in magnetic resonance images  [in Japanese]

    Kajima Y , Takaichi A , Ashida M , Doi H , Tsutsumi Y , Hanawa T , Wakabayashi N

    … Susceptible artifacts generated in magnetic resonance images (MRI) were quantitatively evaluated for Zr-14Nb, Ti-6Al-7Nb, and Co-29Cr-6Mo alloy sphere specimens with different diameter to demonstrate the correlation among magnetic susceptibility, specimen volume, and artifact volume. …

    The journal of the Japanese Society for Dental Materials and Devices 34(5), 377, 2015-09-15

    Ichushi Web 

  • A Simple Method for MR Elastography: A Gradient-Echo Type Multi-Echo Sequence

    Numano Tomokazu , Mizuhara Kazuyuki , Hata Junichi , Washio Toshikatsu , Homma Kazuhiro

    … To demonstrate the feasibility of a novel MR elastography (MRE) technique based on a conventional gradient-echo type multi-echo MR sequence which does not need additional bipolar magnetic field gradients (motion encoding gradient: MEG), yet is sensitive to vibration. … The magnitude image of later generated echo suffered the T2 decay and the susceptibility artifacts, but the wave image and elastogram of later generated echo were unaffected by these effects. …

    Magnetic resonance imaging 33(1), 31-37, 2015-01


  • Optimal Imaging Parameters for Readout-segmented EPI of the Temporal Bone

    AZUMA Toshiya , KODAMA Takao , YANO Takanori , ENZAKI Masahiro , NAKAMURA Masato , MURATA Katsutoshi

    … rs-EPI is affected less by susceptibility artifacts than single-shot EPI (ss-EPI), which is widely used for diffusion-weighted imaging, so rs-EPI is expected to produce less image distortion. … In this study, we compared rs-EPI and conventional ss-EPI of the temporal bone region, which contains abundant amounts of air and frequently exhibits changes in magnetic susceptibility. …

    Magnetic Resonance in Medical Sciences 14(2), 145-152, 2015

    J-STAGE  Ichushi Web 

  • Research & Development of MRI Compatible Au Based Alloys for Biomedical Applications  [in Japanese]

    濵田 賢一

    … Metal-artifact due to volume-magnetic-susceptibility (χ) mismatch between alloy and human-tissue is one of the serious magnetic-resonance-imaging (MRI) artifacts. … Alloys of susceptibility close to that of human-tissue (approximately -9 ppm) are thus required for MRI-artifact-free metal-biomedical-devices. …

    四国歯学会雑誌 26(2), 29-34, 2014-02-14

    IR  Ichushi Web 

  • Visualization of Ovarian Tumors using 3T MR Imaging : Diagnostic Effectiveness and Difficulties

    UEHARA Tomoko , TAKAHAMA Junko , MARUGAMI Nagaaki , TAKAHASHI Aki , TAKEWA Megumi , ITOH Takahiro , KITANO Satoru , NAKAGAWA Hiroyuki , KICHIKAWA Kimihiko

    … Purpose: We evaluated the diagnostic effectiveness of magnetic resonance (MR) imaging at 3 tesla to visualize ovarian tumors and problems associated with its use.<br> … We evaluated visualization of these tumors for image quality and artifacts using 5-point scales. …

    Magnetic Resonance in Medical Sciences 11(3), 171-178, 2012-09-01

    J-STAGE  Ichushi Web  References (23)

  • Microstructure and magnetic susceptibility of dental Zr-Sn alloys to prevent artifacts in MRI  [in Japanese]


    … Microstructure and magnetic susceptibility of Zr-Sn alloys were investigated to develop a novel Zr alloys with a low magnetic susceptibility for magnetic resonance imaging (MRI). … The magnetic susceptibility of Zr-(0-17)Sn alloys decreased with the increase of Sn concentration. …

    The journal of the Japanese Society for Dental Materials and Devices 31(2), 157, 2012-03-25

    Ichushi Web  References (2)

  • Fabrication of Zr/Ag composites to prevent artifacts in MRI for dental applications  [in Japanese]


    … The Zr/Ag composites were fabricated through swaging process, and their magnetic susceptibilities were evaluated using an magnetic balance. … The magnetic susceptibilities of the composites decreased with increasing vol.% of Ag. … In particular, the magnetic susceptibility of the composite containing 81 vol.% of Ag (1.88 x 10^<-5>) was about one-tenth as low as that of Ti (18.0 x 10^<-5>). …

    The journal of the Japanese Society for Dental Materials and Devices 31(2), 65, 2012-03-25

    Ichushi Web  References (1) Cited by (1)

  • The orientation of orthopaedic metallic devices relative to the frequency-encoding gradient affects susceptibility artifacts: an experiment using open MR imaging

    竹内 直英 , 光安 廣倫 , 仲西 知憲 [他] , 西村 須磨子 , 下戸 健 , 日垣 秀彦 , 橋爪 誠 , 岩本 幸英

    整形外科骨接合術材料(以下, インプラント)の周囲に発生するMRI の磁化率アーチファクトを定量化し, 周波数エンコード傾斜磁場の方向の違いによる磁化率アーチファクトの発生について検討することである. 対象と方法 : 2種類の大腿骨近位部骨折用の髄内釘(ステンレス製, チタン製)をゲルファントム内に固定した後に, 0.4 Tesla open MRI(APERTO : 日立メディコ社製)を用いて撮 …

    Fukuoka acta medica 102(5), 185-194, 2011-05-25

    IR  DOI 

  • Mechanical properties of dental Zr-Nb alloys to prevent artifacts in MRI  [in Japanese]


    … Microstructure and mechanical properties of Zr-Nb alloys were investigated to develop novel Zr alloys with a low magnetic susceptibility for magnetic resonance imaging (MRI). … The Zr-Nb alloys consisting of ω phase show low tensile strength brittle fracture, while the magnetic susceptibility is lowest in the alloy. …

    The journal of the Japanese Society for Dental Materials and Devices 29(2), 128, 2010-03-25

    Ichushi Web  References (1)

  • Evaluation of the Susceptibility Artifacts and Tissue Injury Caused by Implanted Microchips in Dogs on 1.5T Magnetic Resonance Imaging

    SAITO Miyoko , ONO Shin , KAYANUMA Hideki , HONNAMI Muneki , MUTO Makoto , UNE Yumi

    … Performing magnetic resonance imaging (MRI) in patients with a metallic implant raises concern over the potential complications, including susceptibility artifacts, implant migration, and heat injury. … This change was consistent with susceptibility artifacts, which rendered the affected area including the spinal cord undiagnostic. …

    Journal of Veterinary Medical Science 72(5), 575-581, 2010


  • The Impact of 3T-MRI on Neurosurgery(<SPECIAL ISSUE>Progress in Neuroimaging)  [in Japanese]

    Fujii Yukihiko , Matsuzawa Hitoshi , Igarashi Hironaka , Nakada Tsutomu

    驚異的に進化し続けてきた磁気共鳴画像(MRI)の歴史に,新たに「臨床機3T-MRI」の頁が加わった.神経科学のための「研究機器」として開発された3T-MRIの臨床での有用性が広く認知されて以来,その普及の勢いはとどまるところを知らず,今や一般病院・医院で通常に稼働する「一般臨床機」となりつつある.3T-MRIは,SNRに優れ,微細病変や種々の脳機能を描出する能力に優れ,脳神経外科診療にさまざまな影 …

    Japanese Journal of Neurosurgery 19(6), 447-454, 2010

    J-STAGE  Ichushi Web  References (21) Cited by (2)

  • Study of Aliasing ERROR with SENSE in Body Diffusion Image Using Single-shot EPI at 3T  [in Japanese]

    MURO Isao , KANEKO Akari , HONDA Masatoshi , HORIE Tomohiko

    Magnetic field inhomogeneity causes artifacts in MRI. … In diffusion-weighted imaging (DWI) using single-shot EPI with SENSE, non-negligible aliasing artifacts often remain in the reconstructed images. … We suppose that these artifacts result from misregistration between the reference images acquired using GRE sequences and the DWI acquired using EPI. …

    Japanese Journal of Radiological Technology 64(12), 1497-1503, 2008-12-20

    J-STAGE  Ichushi Web  References (5)

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