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

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。

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

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.