2型糖尿病患者大脑默认模式网络功能及灰质体积改变的功能MRI研究

Aberrant function connectivity and grey matter volume within default mode network in patients with type 2 diabetes mellitus by functional MRI

目的采用独立成分分析法（ICA）和基于体素的形态测量学（VBM）方法，研究2型糖尿病（T2DM）患者大脑默认模式网络（DMN）功能及其灰质体积的改变。方法2014年5月至2015年1月收集29例T2DM患者（T2DM组）及年龄、性别相匹配的33名继康志愿者（对照组），利用蒙特利尔认知评估（MoCA）及简易精神状态检查量表（MMSE）进行认知评分，然后行脑部静息态fMRI及3DT．WI结构像扫描。利用ICA法处理静息态功能成像数据，分离提取DMN，并利用VBM法得到DMN各脑区的灰质体积。采用双样本t检验对两组DMN的功能网络及灰质体积进行比较，并将差异区的功能连接值（FC）与灰质体积、病程进行Pearson相关分析。结果T2DM组患者较对照组DMN的功能连接减低脑区主要为右侧前扣带回和内侧前额叶皮层（体素数目为121，t=3．81，P〈0．05），两组灰质体积差异无统计学意义，并且差异区的功能网络参与度值与灰质体积无相关性，与糖尿病病程也无相关性。结论T2DM患者大脑DMN的功能连接先于其灰质体积发生变化，提示19MN可能成为一种监测T2DM患者认知损害相关脑部改变的方法。

Objective To explore early aberrant change of the function and grey matter volume within default-mode network in patients with type 2 diabetes mellitus （T2DM） by Independent component analysis and voxel-based morphometry. Methods Twenty-nine T2DM patients and thirty-three healthy control subjects were reeruited in this study between May 2014 and January 2015, and the demographic and clinical data （fasting plasma glucose and HbAle level） were obtained. General cognition was assessed by MMSE and MoCA in all subjects. Resting-state fMRI and T1-weighted imaging were performed in all subjects. Then the z-maps of default-mode network were obtained from Resting-state fMRI by independent component analysis, and the grey matter volumes were extracted by VBM. Finally, two-sample t-test was performed in the function and grey matter volume of DMN between two groups, and pearson correlation coefficients among zFC values extracted from significantly different brain regions, grey matter volumes and durations of T2DM patients were calculated. Results Patients with T2DM showed decreased Z value around the right anterior eingulated cortex and the right medial pre-frontal cortex（eluster=121, t= - 3.81, P〈 0.05）. There was no significant difference in grey matter volume between the two groups, and no correlation between Z value or duration and grey matter volmne was found. Conclusions It suggests the abnormality of connectivity of default-mode network may precede the abnormality of grey matter volume in type 2 diabetes mellitus patients. The DMN might be a new potential tool in monitoring the ehange of cognition in patients with type 2 diabetes mellitus.