静息态功能MRI全脑信号对左侧基底节区脑梗死患者低频振幅的影响

Impact of resting-state functional MRI global signal on amplitude of low-frequency fluctuation in patients with left basal ganglia infarction

目的评价静息态功能MRI(rs-fMRI)全脑信号对左侧基底节区脑梗死患者低频振幅(ALFF)及分数ALFF(fALFF)的影响。方法纳入21例左侧基底节区脑梗死患者(梗死组)及26名健康志愿者(对照组),于去除和未去除全脑信号2种预处理条件下,根据rs-fMRI数据计算ALFF及fALFF,分析梗死组发病7天内(急性期)与3个月(恢复期)之间、后者与对照组之间ALFF及fALFF存在差异的脑区。结果未去除全脑信号条件下,梗死组恢复期大脑双侧额上回、后扣带回(PCC)和健侧壳核ALFF均明显低于对照组(P均<0.05),健侧额下回眶部及颞上回颞极ALFF均明显高于对照组(P均<0.05);梗死组患者恢复期健侧楔叶、颞下回、枕中回ALFF明显高于急性期(P均<0.05)。去除全脑信号条件下,梗死组恢复期健侧额上回、PCC及壳核ALFF均明显低于对照组(P均<0.05),健侧额下回眶部及颞上回ALFF均明显高于对照组(P均<0.05);梗死组恢复期健侧颞下回ALFF明显高于急性期(P<0.05)。梗死组恢复期与对照组、梗死组内不同时期之间各脑区fALFF未见显著差异(P均>0.05)。结论左侧基底节区脑梗死患者随运动恢复而发生脑皮质功能代偿;未去除全脑信号条件下可显示更多ALFF存在差异的脑区。

Objective To observe the imapct of resting-state functional MRI(rs-fMRI)global signal on amplitude of low-frequency fluctuation(ALFF)and fractional ALFF(fALFF)in patients with left basal ganglia infarction.Methods A total of 21 patients with left basal ganglia infarction(infarction group)and 26 healthy volunteers(control group)were enrolled.ALFF and fALFF were calculated according to rs-fMRI data under 2 preprocessing conditions,i.e.with or without the removal of global signal.ALFF and fALFF were compared between acute stage(within 7 days of onset)and convalescent stage(3 months)of infarction group,also between the latter and control group.Results Under the condition of global signal non-regression,ALFF of bilateral superior frontal gyrus,posterior cingulate cortex(PCC)and putamen of the healthy side in convalescent stage of infarction group were significantly lower than those of control group(all P<0.05),while of orbital part of inferior frontal gyrus and temporal pole of superior temporal gyrus of the healthy side were significantly higher than those of control group(all P<0.05).ALFF of cuneus,inferior temporal gyrus,middle occipital gyrus of the healthy side in convalescent stage were significantly higher than those of acute stage in infarction group(all P<0.05).Under the condition of global signal regression,ALFF of superior frontal gyrus,PCC and putamen of healthy side in convalescent stage of infarction group were significantly lower than those of control group(all P<0.05),while of orbital part of inferior frontal gyrus and superior temporal gyrus of the healthy side were significantly higher than those of control group(all P<0.05).ALFF of inferior temporal gyrus of the healthy side in convalescent stage were significantly higher than those of acute stage in infarction group(P<0.05).No difference of fALFF was found between convalescent stage of infarction group and control group,nor between different stages in infarct group(all P>0.05).Conclusion During the motion recovery of left basal ganglia region infarction patients,brain function compensation occurred.Global signal could display relative more brain aeras with changes of ALFF.