摘要
目的 应用fMRI探讨正常受试者不同刺激模式下运动皮质区的活动特征。方法 34例正常受试者采用Block方式分别以左右手简单运动(SM)和复杂运动(CM)模式刺激采集图像,经工作站处理获得功能图像。分析活动区的分布及显示率;测量双侧感觉运动皮质(SMC)区的大小及同侧活动指数(I/C指数);描绘时间-信号强度曲线,测定SMC信号上升百分率(SIRP)。结果 简单运动与复杂运动均可引起SMC、辅助运动区(SMA)、运动前区(PMA)等区域的活动,CM比SM显示率高,但无明显差异。两种模式下对侧SMC区均较同侧SMC区大,P<0.05。右利手者激发的SMC区比左利手者大,同时左右利手者的优势手比非优势手激活SMC区大,但P>0.05。CM比SM引起的同侧活动区大,右利手者非优势手的I/C指数与优势手相比,P<0.05,而左利手者非优势手的I/C指数与优势手相比,P>0.05。SMC区的SIRP在SM和CM下分别为4.05±0.87%和3.43±0.58%,两种模式下相比P<0.05。结论 复杂运动(CM)比简单运动(SM)所激发的对侧和同侧SMC活动区大;对侧SMC活动区大小与有利手无明显相关性,而同侧SMC活动区的大小与有利手呈相关性,左利手者比右利手者明显。
Purpose To test the correlation between time of echo(TE) with signal-to-noise(SNR) andactivation of the motor areas with 1.5T functional MRI.Methods 34 healthy volunteers were scannedduring the alternative simple motor task of the left and right hand.The original data were acquired withdifferent TE(30ms、60ms、90ms) using GRE-EPI sequence.The SNR was measured in both sides of the handrepresentation area(HRA) and supraparietal area(SPA) regions. The relative signal rising ratio(ΔS/S)of the activation in the sensorimotor cortex(SMC) was calculated. Meanwhile, the distribution and extentof the activation were observed. Results The SNRs of both of the HRA and SPA were decreased while theTE increased, q-test showed statistically significant. The SNR in HRA was significantly larger than thatin SPA.ΔS/S of the SMC region increased with the TE increasing and P value of the neighbouring groupswas less than 0.05. The activation areas were scattered and the extent was expanded.Conclusion In BOLDfunctional MR imaging, TE is a key factor and 60ms is the optimal choice so as to achieve the best imagingquality.
出处
《国际医药卫生导报》
2003年第18期4-7,共4页
International Medicine and Health Guidance News
关键词
功能MRI
简单运动
复杂运动
有利手
活动区
functional magnetic resonance imaging(fMRI) TE SNR Susceptibility Artifact
