轻度阿尔茨海默病患者脑功能网络度中心度改变的初步研究

Investigation of functional networks changes using degree centrality in patients with mild Alzheimer’s disease

目的:利用度中心度(degree centrality,DC)的方法探讨轻度阿尔茨海默病(Alzheimer's disease,AD)患者及遗忘型轻度认知功能障碍(amnestic mild cognitive impairment,aMCI)患者在静息态下脑功能网络连接属性的改变。方法:收集12例轻度AD患者、12例aMCI患者和15名健康老年志愿者(normal control,NC组)参加试验。所有受试者均行简易精神状态检查量表(mini-mental state examination,MMSE)及其他系列量表测试,评估其认知水平,并采集静息态功能MRI数据,经预处理和后处理计算出全脑DC值图,采用双样本t检验进行组间比较,分别检测轻度AD组与NC组、aMCI组与NC组间DC分布图间的统计学差异。结果:与NC组相比,轻度AD患者DC值减低的脑区主要分布在左侧眶部额下回、左侧额中回、左侧额下回、左侧后扣带回及右侧后扣带回;aMCI患者则分布于右侧楔前叶、左侧楔叶、右侧楔叶、右侧枕上回、右侧枕中回、左侧颞上回及右侧角回脑区DC值较NC组减低,而右侧前扣带回、左侧海马、左侧胼胝体压部的DC值较NC组升高。结论:基于静息态功能MRI数据的DC分析观察到轻度AD患者及aMCI患者在一些脑区发生了功能连接改变,DC作为一种新的基于体素水平描述脑网络属性的方法,可能对理解AD病理机制及观察其脑网络属性的改变提供了一个新视角。

Objective： To investigate the value of degree centrality （DC）, a novel resting-state fMRI parameter, in voxel-wise whole-brain functional networks analysis in mild Alzheimer＇s disease （AD） patients and amnestic mild cognitive impairment （aMCI） patients as compared with that in normal controls. Methods： Twelve patients with mild AD, 12 patients with aMCI, and 15 healthy aging volunteers served as normal controls were recruited. Their cognitive functions were evaluated by the mini mental state examination （MMSE） and other clinical scales. The resting-state BOLD-fMRI data were acquired and preprocessed. Analysis of DC map changes between the two patient groups and the control group were performed by two sample t test. （threshold at/〉〈0.05）. Results： Compared with the control group, patients with mild AD showed significantly reduced DC value in left orbital frontal gyrus, left middle frontal gyms, left inferior frontal gyms, left posterior cingulate and right posterior cingulate. In aMCI patients, significantly reduced DC value was found in right precuneus, left cuneus, right cuneus, right superior occipital gyms, right middle occipital gyms, left superior temporal gyrus and right angular gyms;interestingly, increased DC value was observed in right anterior cingulate gyms, left hippocampus, left side of the corpus callosum. Conclusions： Changes of DC value occurred in some region of brain in the two patient groups when compared with the control group. It was indicated that DC, as a novel resting-state fMRI parameter in the voxel-wise whole-brain functional networks, might be an appealing alternative approach for further study on pathologic and neuropsychological states of AD.