基于图论分析的血管性认知障碍患者的脑结构网络拓扑属性研究

Study of structural network topological properties of vascular cognitive impairment based on graph theory anlysis

目的:采用DTI及图论分析方法,探讨血管性认知障碍(VCI)患者脑结构网络全局拓扑属性改变,及其与认知功能的相关性。方法:纳入20例VCI患者(VCI组)和20例健康志愿者(对照组)分别行DTI扫描和认知能力评估。基于图论的方法构建全脑结构网络,计算全局网络拓扑属性,2组脑结构网络拓扑属性差异行两独立样本t检验,将VCI组中与对照组差异有统计学意义的指标与蒙特利尔认知评估量表(MoCA)评分行相关性分析。结果:2组均具有小世界属性,相比对照组,VCI组的Eg和局部效率(Eloc)均下降,而最短路径(Lp)增加(均P<0.05)。VCI组Eg和Eloc均与MoCA评分呈正相关(r=0.544,0.516;均P<0.001),Lp与MoCA评分呈负相关(r=-0.576,P<0.001)。结论:VCI患者脑结构网络受到破坏,表现为网络的全局和局部传输能力下降,以及网络信息传输速度变慢,并与认知能力下降存在显著的相关性;结构网络拓扑属性的改变可能是VCI患者认知受损的原因之一。

Objective:To investigate the changes in global topological properties of structural brain networks and their correlation with cognitive function in patients with vascular cognitive impairment(VCI)using diffusion tensor imaging(DTI)and graph theory analysis.Methods:Twenty patients with VCI and 20 healthy controls underwent DTI scan and cognitive ability assessment.The graph theory was used to construct a whole-brain structural network and calculate global network topological attributes.Two independent sample t test was used to obtain differences in global indicators between the two groups and to correlate them with MoCA scores.Results:All subjects in two groups had small-world attributes.Compared with the subjects in the control group,global efficiency(Eg)and local efficiency(Eloc)decreased in the VCI group,while characteristic path length(Lp)increased(all P<0.05).Correlation analysis showed that Eg and Eloc in the VCI group were positively correlated with MoCA scores(r=0.544,0.516,both P<0.001),and Lp was negatively correlated with MoCA scores(r=-0.576,P<0.001).Conclusions:The structural network of VCI patients is damaged,which is manifested by the decline in the global and local transmission capacity of the network and the slow transmission speed of network information,and has a significant correlation with the decline in cognitive ability.The changes in the topological properties of the structural network may be responsible for the cognitive impairment of VCI patients.