摘要
目的了解被检体、线圈间的耦合与线圈信噪比(sNR)的关系。方法 MR 扫描时,在头、体线圈中使用不同形状的水模及不同放置,做 SNR 测量序列扫描,检测 SNR。结果扁圆柱体W100水模在头线圈中轴向放置时 SNR(55.47±0.69)比径向放置时(46.59±1.36)高(t=16.48,P<0.01),也比水平向放置时(46.32±0.88)高(t=23.15,P<0.01),差异有统计学意义;扁圆柱体W100水模在体线圈中轴向放置时 SNR(20.35±0.29)比径向放置时(19.52±0.42)高(t=4.60,P<0.01),也比水平向放置时(19.68±0.46)高(t=3.52,P<0.01),差异有统计学意义。直径较小的长圆柱体自制水模,中央轴对称放置于头线圈时 SNR(27.64±0.83)比侧移或倾斜时(26.32±0.85)高(t=3.30,P<0.01),差异有统计学意义。结论以线圈中心轴为对称轴放置被检体,可提高线圈SNR。
Objective To study the relationship between object-coil coupling and coil signal to noise ratio （SNR）. Methods The SNR of the coil was measured and calculated using different shapes of the phantom and different positions in head or body coils. Results When oblate cylinder was placed axially in head coil, it＇s SNR （55.47 ±0. 69） was better than that at sagittal position（46. 59 ± 1.36） （ t = 16.48, P 〈 0. 01 ） and that at coronal position （ 46. 32 ± 0. 88 ） （ t = 23.15, P 〈 0.01 ）, the differences were statistically significant. When oblate cylinder was placed axially in body coil, it＇s SNR （20. 35 ±0. 29）was better than its sagittal position （ 19. 52 ± 0.42 ） （ t = 4.60, P 〈 0.01 ） and its coronal position （ 19.68 ± 0.46） （ t = 3.52, P 〈 0. 01 ）, the differences were statistically significant. When a tall cylinder centered symmetrically in head coil, the SNR was better （ 27.64 ± 0. 83 ） than that at lateral or oblique positions （26. 32 ± 0. 85 ） （ t = 3.30,P 〈 0. 01 ） and the difference was statistically significant. Conclusion Center-symmetrical position of the examined object could improve the SNR of the coils.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2007年第10期1107-1108,共2页
Chinese Journal of Radiology
关键词
磁共振成像
体模
显象术
研究技术
Magnetic resonance imaging
Phantoms,imaging
Investigative techniques
