中文摘要：

目的：利用图论方法探索轻度认知功能障碍（MCI）患者大脑各脑区点介性的异常改变。方法：采集13名MCI患者和17名正常老年人（NC）的大脑静息态BOLD-f MRI数据。采用SPM8和DPARSF软件包进行数据预处理;构建大脑功能网络,并计算Sparsity=0.18（网络收益最大）时90个脑区的点介性。采用双样本t检验分别比较两组90个脑区点介性的差异。结果：两组人额上回、岛叶、楔前叶、前扣带和旁扣带回等区域点介性较大;中央扣带回、右海马区、杏仁核、枕下回、左梭状回、豆状核和右颞中回等区域点介性较小。MCI患者右额上回、右岛叶、右梭状回、左缘上回、右角回和左中央旁小叶6个区域点介性显著高于正常老年（P〈0.05）;右额下回鳃盖部、右辅助运动区和右舌回3个区域点介性显著低于正常老年（P〈0.05）。结论：MCI患者大脑多个区域信息传递能力发生了异常改变,提示在MCI的诊断与鉴别诊断中应重点关注这些区域。

英文摘要：

Purpose： To explore the betweenness centrality of brain areas between patients with mild cognitive impairment（MCI） and normal elders（NC） by graph theory.Methods：Resting-state Bold-f MRI data of 13 MCI patients and 17 healthy elders were acquired and preprocessed with SPM8 and DPARSF software. Then brain＇s functional network of each subject was constructed by Matlab software. Betweenness centralities of 90 brain areas were calculated at Sparsity = 0.18, where the network earning was maximal. Two-sample t-test was adopted to test the difference of betweenness centrality of 90 brain areas between MCI patients and NCs. The result was presented by REST software.Results：Betweenness centralities of superior frontal gyrus, insula, precuneus, anterior cingulate and paracingulategyri of both groups were larger.Betweenness centralities of median cingulate and paracingulate gyri, right hippocampus, amygdala, inferior occipital gyrus, left fusiform gyrus, lenticular nucleus, and right middle temporal gyrus of both groups were smaller.The betweenness centralities of right superior frontal gyrus, right insula, right fusiform gyrus, left supramarginal gyrus, right angular gyrus, and left paracentral lobule in MCI patients were significantly larger than that in normal elders（P〈0.05）. The betweenness centralities of right inferior frontal gyrus（opercular part）, right supplementary motor area, and right lingual gyrus in MCI patients were significantly smaller than that in normal elders（P〈0.05）.Conclusion： The information transfer ability of several brain areas in MCI patients were change dabnormally, indicating more attention should be paid on those areas..