2 0 0 0 OA 対向アレイコイルによる手部MRIの感度領域の拡張
- 著者
- 高津 安男 山村 憲一郎 宮地 利明 木村 哲哉 上山 毅 石黒 秋弘
- 出版者
- 公益社団法人 日本放射線技術学会
- 雑誌
- 日本放射線技術学会雑誌 (ISSN:03694305)
- 巻号頁・発行日
- vol.68, no.10, pp.1346-1353, 2012-10-20 (Released:2012-10-22)
- 参考文献数
- 8
It is difficult for Rheumatoid Arthritis (RA) patients to remain in a strenuous position for a long time during examinations. The field of view (FOV): 250 mm is needed for hand examinations from the wrist to the finger. Two channel phased array coils are effective to use when examinations of the ‘off center’ are taken for the upper and lower extremities. The area of the array coils’ sensitivity can be expanded by shifting both coil elements 40–60% in the opposite direction of the element’s diameter. This method is given credibility due to the increased signal-to-noise ratio (SNR) in the peripheral regions (shifted directions), but loses value in the central area, as indicated by the decrease in SNR. This was confirmed in the image of the hand using visual assessment including the fat suppression technique. It was verified that the sensitivity area was expanded using Scheffe’s method of paired comparison (Ura’s modified method). An application at the other regions of the body can be expected to be used in the case of using parallel positioned coils during clinical situation.
1 0 0 0 OA MRI装置におけるdB/dt値の実測について
- 著者
- 本郷 隆治 小倉 明夫 井上 博志 林 浩二 石黒 秋弘
- 出版者
- 公益社団法人 日本放射線技術学会
- 雑誌
- 日本放射線技術学会雑誌 (ISSN:03694305)
- 巻号頁・発行日
- vol.57, no.5, pp.573-580, 2001-05-20 (Released:2017-06-30)
- 参考文献数
- 8
In recent years, as gradient magnetic resonance imaging (MRI)systems have become larger and faster, the influence of low-frequency alternating magnetic fields on the human body during rapid scanning have become significant in terms of patient health. It has become more important to monitor time-variant magnetic fields (dB/dt). From this point of view, we measured the maximum dB/dt for clinical scanning using a self-made search coil and storage oscilloscope that conformed to international standard IEC 60601-2-33(1995). The results were almost the same as the calculated values. In this brief report, we introduce to clinical operators the method of measuring maximum dB/dt.