磁振造影線性脊椎表面線圈之自製經驗

The Experience of Making a Lumbar Surface Coil for MRI

江志明(Chih-Ming Chiang) ； 李三剛(San-Kan Lee) ； 廖泰杉(Tai-Shan Liao) ； 謝彩堂(Tsae-Tang Shieh) ； 陳中和(Jeon-Hor Chen)

《中華放射線醫學雜誌》 19卷3期 (1994/09) Pp. 241-247

摘要

Better quality of magnetic resonance imaging (MRI) can be obtained by increasing the signal intensity and decreasing the noise. The application of surface coil can reduce the distance between the imaging object and receiver, and hence not only increases the receiving signals but also improves the image resolution and at the same time magnifies the visual field. The surface coils supplied by the manufactures are expensive and in certain cases inadequate for examination in some special locations. Therefore, it is important to design a coil that is adequate for some special clinical applications. This study, described our experience in designing an extended planar lumbar surface coil having a Q value of 21.875 which was lower than the value from the manufacture's (99.647) due to a poorer quality of the materials. In the aspect of the signal-to-noise ratio (SNR) of phantom, the manufacture's coil was better (73.79 vs. 47.69), possibly due to the increasing size of the home-made surface coil. The SNR of our coil measured from 10 patients were lower as well (66.03 vs. 76.93). However, close correlation was noted between these two surface coils (r=0.985 p＜0.0001). Although both type of coil showed no significant difference in image resolution and diagnostic value, our home-made coil seemed to have better results judged from background noise and image homogeneity. This surface coil definitely extended the field of view, especially at the thoracolumbar junction, and decreased the misdiagnosed cases. This experience extended our knowledge in making the coils for other purposes.

關鍵字

磁振造影 ； 射頻 ； 訊噪比 ； 表面線圈

並列摘要

Better quality of magnetic resonance imaging (MRI) can be obtained by increasing the signal intensity and decreasing the noise. The application of surface coil can reduce the distance between the imaging object and receiver, and hence not only increases the receiving signals but also improves the image resolution and at the same time magnifies the visual field. The surface coils supplied by the manufactures are expensive and in certain cases inadequate for examination in some special locations. Therefore, it is important to design a coil that is adequate for some special clinical applications. This study, described our experience in designing an extended planar lumbar surface coil having a Q value of 21.875 which was lower than the value from the manufacture's (99.647) due to a poorer quality of the materials. In the aspect of the signal-to-noise ratio (SNR) of phantom, the manufacture's coil was better (73.79 vs. 47.69), possibly due to the increasing size of the home-made surface coil. The SNR of our coil measured from 10 patients were lower as well (66.03 vs. 76.93). However, close correlation was noted between these two surface coils (r=0.985 p＜0.0001). Although both type of coil showed no significant difference in image resolution and diagnostic value, our home-made coil seemed to have better results judged from background noise and image homogeneity. This surface coil definitely extended the field of view, especially at the thoracolumbar junction, and decreased the misdiagnosed cases. This experience extended our knowledge in making the coils for other purposes.

並列關鍵字

Magnetic resonance MR, surface coil ； magnetic resonance MR, technology ； spin, MR