静息态fMRI观察左侧基底核区脑梗死特定频段低频振幅改变

Resting-state fMRI observation on amplitude of low-frequency fluctuation changes at specific frequencies in patients with left basal ganglia region infarction

目的探讨左侧基底核区梗死患者在特定频段(slow-4:0.027~0.073 Hz,slow-5:0.010~0.027 Hz)下低频振幅(ALFF)改变,追踪其大脑自发活动纵向变化。方法对25例左侧基底核区脑梗死患者(梗死组)和26名正常志愿者(对照组)采集静息态fMRI数据;采用混合效应分析,针对梗死组慢性期与梗死组急性期、梗死组慢性期与对照组,分别计算其ALFF值频率间、组间主效应脑区差异;于2个频段下进行事后检验,获得组间有差异脑区。结果 ALFF结果显示,两个频段间存在差异性脑区,slow-4频段激活脑区位于皮层下脑区,slow-5频段激活脑区多位于默认网络。在slow-4频段上,梗死组慢性期与急性期对比,慢性期患者双侧顶上小叶、楔前叶、枕叶及健侧颞叶ALFF值升高,扣带回和辅助运动区ALFF值降低;梗死组慢性期与对照组对比,慢性期患者健侧后扣带回和患侧中央前回ALFF值降低,健侧侧部额叶脑回和额极ALFF值升高。在slow-5频段未见差异脑区。结论 slow-4频段显示左侧基底核区脑梗死患者脑自发活动更为敏感;患者恢复过程中存在脑皮质功能重构。

Objective To explore the changes of amplitude of low-frequency fluctuation (ALFF) in specific frequency bands (slow-4: 0.027-0.073 Hz,slow-5: 0.010-0.027 Hz),and to investigate the longitudinal spontaneous neuron activity changes in patients with left basal ganglia region infarction.Methods Resting-state fMRI data of 25 patients with left basal ganglia region infarction (infarction group) and 26 normal participants (control group) were obtained.Based on two group contrasts of chronic phase and acute phase,chronic phase and normal control,the method of mixed effect analysis was used to compute the frequency differences and group differences.Then post-hoc test was used to examine the group differences at slow-4 and slow-5 frequency band separately.Results ALFF analysis results showed significant frequency difference between the 2 frequency bands,with activated brain region of slow-4 located in subcortical region,and slow-5 located in default mode network.At slow-4 frequency band,in the contrast of chronic phase and acute phase,patients in chronic phase showed increased ALFF value at bilateral superior parietal lobule,precuneus,occipital cortex and contralateral temporal cortex,while decreased ALFF value at bilateral cingulum gyrus and supplementary motor area.In the contrast of chronic phase and normal control,ALFF values of chronic phase patients decreased at contralateral posterior cingulate (PCC) and ipsilateral precentral gyrus,whereas increased at contralateral lateral frontal lobule and frontal pole.There was no significant difference of two group contrasts at slow-5 frequency band.Conclusion Slow-4 frequency band is sensitive to show spontaneous brain activity in patients with left basal ganglia region infarction,and the cortical function is reconstructed during motor recovery.