脑卒中静息态下脑活动异常的比率低频振幅fMRI研究

目的运用静息态功能磁共振成像(resting-state functional magnetic resonance imaging,rs-f MRI)的比率低频振幅(fractional amplitude of low frequency fluctuation,f ALFF)方法探究慢性期脑卒中患者基线脑活动异常变化。材料与方法16例慢性期左侧皮层下病变脑卒中患者和16例年龄性别相匹配的健康志愿者均接受静息态功能磁共振扫描,在0.01~0.08 Hz频段内计算f ALFF值,运用双样本t检验(P0.05,Alpha Sim矫正)比较两组间的f ALFF差异。结果与健康对照组比较,脑卒中患者组f ALFF值显著降低区域主要位于病灶同侧丘脑和基底节区,其中丘脑的f ALFF值与患者临床手功能评分呈正相关(r=0.54,P=0.030.05)。结论脑卒中自发神经活动异常与病灶部位和病灶所致的手运动功能障碍密切相关,这些发现有助于进一步阐释脑卒中运动功能障碍的病理生理学机制。

A fractional amplitude of low frequency fluctuation study of resting-state fMRI in stroke

Objective:To investigate the abnormal changes in baseline brain activity of the chronic stroke patients by using fractional amplitude of low frequency fluctuation(fALFF)ofresting-statefMRI.Materials and Methods:Sixteenchronic stroke patients with left subcortical lesions and sixteen age and sex-matched healthy volunteers were performed resting-state fMRI scans. Values of fALFF were calculated in the frequency ranging from 0.01–0.08 Hz. Two-sample t-test was performed to compare the differences in fALFF between the two groups (P<0.05, corrected by AlphaSim). Results:Compared with the healthy controls, the areas where the fALFF values decreased in stroke patients mainly located in the ipsilesional thalamus and basal ganglia, of which, the fALFF values of the ipsilesional thalamus showed significantly positive correlation with the Fugl-Meyer Assessment (FMA) scores in stroke patients (r=0.54, P=0.03<0.05). Conclusion:The abnormal spontaneous neural activity of the stroke is closely related to lesions site and hand motor dysfunction. These findings help us to further understand the pathophysiological mechanisms of the motor dysfunction in stroke.