中文摘要：

目的探讨遗忘型轻度认知障碍（aMCI）患者的静息态全脑功能连接强度（FCS）特征，以寻找新的可用于反映阿尔茨海默病（AD）高风险人群脑功能网络拓扑属性特征的指标。方法2009年9月至2011年4月纳入aMCI患者31例（aMCI组）以及年龄、性别和受教育程度相匹配的健康志愿者42名（对照组）。采集所有被试的静息态fMRI（rs-fMRI）数据，对rs-fMRI数据进行常规预处理并进行全脑的FCS分析，探索aMCI患者全脑功能网络的核心脑区（hub），即FCS值较高脑区的分布特征。采用双样本t检验比较两组被试间年龄、受教育年限、各项神经心理学测评的差异，采用卡方检验比较两组间性别的差异，组间FCS的差异采用一般线性模型分析。最后，在aMCI患者组中采用相关分析评估具有组间差异脑区的FCS值与行为学评分的相关性。结果aMCI组脑功能网络的核心脑区主要分布在大脑的联络皮层区域，如楔前叶、扣带回后部、内侧前额叶、角回、枕上回、梭状回、舌回等，与对照组的分布模式大体一致，但FCS值普遍降低。进一步组间比较显示，aMCI组较对照组在双侧梭状回、舌回、枕上回、左侧枕中回、中央后回等区域的FCS值显著下降（簇大小分别为389、230、187、107个体素，P值均〈0．05），在双侧扣带回后部、右侧岛叶FCS值有下降的趋势。相关性分析显示，在未经校正的条件下，左侧中央后回的FCS值与画钟试验（CDT）评分具有相关性（r=0．436，P=0．026）。结论aMCI主要破坏脑功能网络中的核心脑区，这种功能连接的变化可能反映了早期AD的病理生理变化。

英文摘要：

Objective To explore a new index for reflecting the topological information of brain functional networks in patients at high risk of Alzheimer disease using characteristics of resting-state functional connectivity strengths（FCS） in patients with amnestic mild cognitive impairment（aMCl）. Methods Thirty-one aMCI patients and 42 age, gender and years of education matched normal controls were enrolled between September 2009 and April 2011 in this study. The resting-state functional MRI （rs-fMRI） data of all participants were acquired and preprocessed. Then the whole-brain functional connectivities were constructed for exploring the distribution characteristics of hub regions which had higher FCS values. Using two-sample t test to compare group differences in age, years of education and each neuropsychological assessment. In addition, using Chi-squared test to compare group differences in gender. Group differences in FCS values were analyzed by general linear model. Finally, correlation analyses were used to evaluate the relationships between the FCS values of the brain regions with group differences and behavioral scores in aMCI patients. Results The hub regions of the functional networks in the aMCI patients were mainly located in the association cortices such as the precuneuses, posterior cingulate cortices, medial prefrontal cortices, angular gyri, superior occipital gyri, fusiform gyri and lingual gyri. The distribution models in the aMCI patients were consistent with those in the normal controls. However, the FCS values of these brain regions were significantly lower in the aMCI patients than those in the normal controls. In comparison to the normal controls, the aMCI patients had significantly decreased FCS values in the bilateral fusiform gyri, lingual gyri, superior occipital gyri, left middle occipital gyms and postcentral gyms （the cluster was 389, 230, 187 and 107 voxels, respectively; P〈0.05, respectively）, and they had decreased trends of FCS values in the bilateral posterior cingulate