阿尔茨海默病及轻度认知障碍所致脑灰质体积及脑功能改变

目的基于体素形态学分析(VBM)及静息态功能MRI(rs-fMRI)技术观察阿尔茨海默病(AD)及轻度认知障碍(MCI)患者全脑灰质体积及功能改变。方法对AD(AD组)、MCI患者(MCI组)各30例及正常老年人30名(HC组)采集rs-fMRI和三维磁化强度预备梯度回波序列T1加权像,比较3组全脑灰质体积、脑区分数低频振幅(fALFF)和功能连接(FC)差异。结果3组间左侧颞上回、双侧颞中回及海马旁回灰质体积差异有统计学意义;左侧距状皮层、左侧尾状核、左侧中央后回、右侧颞上回、右侧顶上回、左侧中央前回、右侧楔前叶、右侧额中回及右侧中央后回fALFF值差异有统计学意义(P均<0.05)。以左侧颞上回为种子点,AD及MCI患者同侧颞下回与对侧枕下回FC增强。结论联合运用VBM及rs-fMRI技术可为早期诊断MCI及AD提供参考依据。AD及MCI可致全脑广泛fALFF减低及同侧颞叶与对侧枕叶FC增强,AD可伴有颞叶体积减小,MCI脑灰质体积无显著改变。

Alterations in gray matter volume and brain function in Alzheimer disease and mild cognitive impairment

Objective To investigate the changes of whole brain gray matter volume and brain function of Alzheimer disease (AD) and mild cognitive impairment (MCI) using voxel-based morphometry (VBM) and resting-state fMRI (rs-fMRI). Methods Thirty AD patients (AD group), 30 MCI patients (MCI group) and 30 age, sex and education level matched healthy old individuals (HC group) were enrolled and underwent rs-fMRI and three-dimensional magnetization prepared rapid acquisition gradient echo sequence scanning. The gray matter volume, fractional amplitude of low-frequency fluctuation (fALFF) and seed-based functional connectivity (FC) were compared among 3 groups. Results The gray matter volume of left superior temporal gyrus, bilateral middle temporal gyrus and parahippocampal gyrus were significant different among 3 groups, aso as values of the left calcarine, left caudate nucleus, left postcentral gyrus, right superior temporal gyrus, right superior parietal gyrus, left precentral gyrus, right precuneus gyrus, right middle frontal gyrus and postcentral gyrus (all P<0.05). Taken the left superior temporal gyrus as the seed point, increased FC in ipsilateral inferior temporal gyrus and contralateral inferior occipital gyrus were found in MCI and AD patients. Conclusion Combination of VBM and rs-fMRI technology was helpful to early diagnosis of MCI and AD. AD and MCI patients showed extensive reduction of fALFF values in the whole brain and increased FC in the ipsilateral temporal lobe and contralateral occipital lobe, AD patients were accompanied by a decrease in temporal lobe volume, while MCI patients showed no significant changes of gray matter volumes.