著者

高木 祐一 橋田 昌弘 小味 昌憲 羽手村 昌宏

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.77, no.10, pp.1186-1195, 2021 (Released:2021-10-20)

参考文献数

16

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When the fat-suppression technique was used in the MRI examinations of neck and extremities, incomplete regions of fat suppression were depicted frequently. These incomplete regions were caused by the non-uniform static magnetic field (B0). On the other hand, a non-uniform B0 caused banding artifacts using a balanced steady-state free precession (bSSFP) sequence. We investigated the prediction of incomplete regions of fat suppression using the banding artifacts of the bSSFP sequence. The fat-suppression techniques used in this study were the chemical shift selective and spectral adiabatic inversion recovery methods for turbo spin echo imaging. Using an oil bottle attached to a staple, the scan parameters of the bSSFP sequence were adjusted to overlap with the banding artifacts in the incomplete regions of fat suppression. The neck, ankle joint and femur of healthy volunteers were scanned using the obtained scan parameters, and a visual assessment was performed. As a result, the incomplete region of fat suppression matched the region of the banding artifact. We were able to predict the incomplete region of fat suppression using the banding artifacts of the bSSFP sequence. If the optimized bSSFP sequence is used as the localizer, we can assess the situation of incomplete fat suppression before the main scanning and reduce rescanning due to incomplete fat suppression.

著者

土井 康寛 松山 倫延 池田 龍二 橋田 昌弘

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.72, no.7, pp.581-588, 2016 (Released:2016-07-20)

参考文献数

25

被引用文献数

1

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This study was conducted to measure the recognition time of the test pattern and to investigate the effects of the maximum luminance in a medical-grade liquid-crystal display (LCD) on the recognition time. Landolt rings as signals of the test pattern were used with four random orientations, one on each of the eight gray-scale steps. Ten observers input the orientation of the gap on the Landolt rings using cursor keys on the keyboard. The recognition times were automatically measured from the display of the test pattern on the medical-grade LCD to the input of the orientation of the gap in the Landolt rings. The maximum luminance in this study was set to one of four values (100, 170, 250, and 400 cd/m2), for which the corresponding recognition times were measured. As a result, the average recognition times for each observer with maximum luminances of 100, 170, 250, and 400 cd/m2 were found to be 3.96 to 7.12 s, 3.72 to 6.35 s, 3.53 to 5.97 s, and 3.37 to 5.98 s, respectively. The results indicate that the observer’s recognition time is directly proportional to the luminance of the medical-grade LCD. Therefore, it is evident that the maximum luminance of the medical-grade LCD affects the test pattern recognition time.