| Project/Area Number |
03670948
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
外科・放射線系歯学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
YONETSU Koichi Kyushu University,Faculty of Dentistry,Instructor, 歯学部, 助手 (70167039)
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| Co-Investigator(Kenkyū-buntansha) |
FUKAI Toyofuku Kyushu University,School of Health Sciences,Associate professor, 医療短大, 助教授 (10117179)
YUASA Kenji Kyushu University,Faculty of Dentistry,Instructor, 歯学部, 助手 (40136510)
TABATA Osamu Kyushu University,Faculty of Dentistry,Instructor, 歯学部, 助手 (50150470)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1992: ¥400,000 (Direct Cost: ¥400,000)
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| Keywords | MRI / Artifact / Dental metals / Spin-echo / Gradient-echo / ア-チファクト / 歯科用合金 / 永久磁石型 / 超電導型 |
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| Research Abstract |
Magnetic Resonance Imaging(MRI)is becoming an important method in evaluating various pathologic conditions of oral and maxillofacial region.Unfortunately,certain dental materials cause variable artifacts on MR images that can obscure the relation between the normal surrounding tissues and the pathologic conditions.The purpose of this study is to evaluate the potential producing artifacts from various dental metallic materials in vitro.The results obtained by each material in vitro were compared with the artifacts usually observed in vivo.Thirteen rectangle-shaped metals (1.2x10x20mm)and two types of surgical plate commonly used in the dentistry were tested in this study.MRI were obtained with a 1.0-T superconducting magnet(SMT-100,Shimadzu)and 0.2-T permanent magnet(MRP-20-2,Hitachi Medico).The images were acquired with a spin-echo and a gradient-echo pulse sequences.
The following results were obtained: (1)Three types of MR artifacts could be identified;1)Focal loss of signal intensity,2)High signal intensity surrounding the focal loss signal area,3)Distortion of image. (2)All dental materials were seen to cause artifacts.The biggest artifact was due to a surgical stainless steel plate composed of ferromagnetic(high permeability). (3)The artifacts obtained with the 1.0-T MR system were bigger than that obtained with a 0.2-T one. (4)According to in vivo studies,it is suggested that thickness and shape of metal is one of the factors that cause artifacts.Such studies are now being carried out in vitro.
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