实时功能磁共振成像对运动皮层的定位

Localization of motor cortex by real-time imaging process functional MRI during finger movements

目的 :探讨研究RTIP fMRI对“手结节”的功能定位及正常和病理状态下对指运动时运动皮层的功能改变。方法 :采用GE 1 .5TMRI扫描机及具有RTIP功能的工作站 ,成像序列为单次激发梯度回波平面回波成像。 1 0例右手利健康志愿者及 3例额顶叶病例作为研究对象 ,运动激活由大拇指和其它四指的依次对指运动所组成 ,数据分析采用“相关系数”几何算法。结果 :①RTIP fMRI能对“手结节”准确定位 ,并且功能图与解剖图上“手结节”有很好的对应关系 ;②对指运动时运动皮层的激活包括对侧M1 /S1区 (M1区包括大部分“手结节”) ,SMA区及同侧少量M1区 ;③时间过程图呈“城垛样”改变 ,相关系数范围为 0 .51～ 0 .88;④对于额顶叶占位病变 ,RTIP fMRI能准确显示M1区的移位变形及受累。结论 :RTIP fMRI能对运动皮层准确定位 ,具有其它fMRI技术无法比拟的优越性 。

Objective:To study the correspondence between structure and function of the 'hand knob' on the precentral gyrus and functional changes of motor cortex during self paced finger movements by RTIP fMRI in normal and abnormal conditions.Methods:10 right handed healthy volunteers and 3 patients with frontoparietal space occupying lesions were studied. fMRI were performed with a single shot, gradient echo echo planar pulse sequence on 1.5T GE scanner and real time image processing technique on the workstation. The activation tasks consisted of self paced finger movements performed with the right and left hand. Image postprocessing was done on the workstation by 'correlation coefficient' algorithm analysis method.Results:①There was a good correspondence between anatomical landmarks of 'hand knob' and the somatotopical organization of primary motor areas in 10 volunteers.②During finger task, functional changes occurred in the contralateral primary motor somatosensory cortex(M1/S1), most often containing 'hand knob' structure, the supplementary motor area(SMA), and ipsilateral primary motor cortex. ③The time course plot of the 'hand knob' in primary motor cortex matched to 'box car' reference wave form, the correlation coefficient between the experimental and the reference plots is 0.51～0.88.④In the cases of frontoparietal space occupying lesions,a displacement or edema of 'hand knob' was demonstrated clearly by RTIP fMRI. Conclusion: RTIP fMRI,a promising new technique, can localize motor cortex accurately.It is superior to any other fMRI techniques,may be put widely into use of function research of the brain.