摘要目的 探讨脑白质疏松(leukoaraiosis,LA)对大脑功能网络效率的影响,分析其小世界特性的变化.方法 研究对象来源于北京天坛医院2014年1月～2015年9月门诊的34例脑白质疏松患者和23名年龄、性别、受教育程度相匹配的正常老年人(NC组),运用简易精神状态检查量表(MMSE)、蒙特利尔认知评估量表(MoCA)、临床痴呆评定量表(CDR)进行评定,将脑白质疏松组分为LA认知正常(CN,cognitive normal)组[LA(CN)组,n=11]、LA非痴呆型血管性认知功能障碍(VCIND,vascular cognitive impairment-non dementia)组[LA(VCIND)组,n=23].采集大脑静息态功能核磁共振(BOLD-fMRI)图像,进行功能网络建立和小世界属性分析.结果 以连接矩阵的稀疏度(sparsity)为阈值,在0.05～0.5范围内,三组受试者的δ值均＞1,均具有小世界属性.LA(CN)组及LA (VCIND)组的λ均低于正常老年人,即越接近于1.LA(CN)组γ均高于正常人;LA (VCIND)组γ均低于正常人.LA(CN)组δ均高于正常人;LA(VCIND)组δ均低于正常人.结论 LA患者大脑功能网络的小世界特性受损,与正常人相比,LA认知正常组小世界属性增强,而LA认知功能障碍组的小世界网络特性减低,表明LA患者的脑网络拓扑组织结构受损可能与认知障碍相关.

abstractsObjective To explore the effect of leukoaraiosis (LA) on the efficiency of the brain function network and to analyze the features of the "small world" network with graph theory method.Methods This study involved 34 LA patients from the Department of Neurology,Beijing Tiantan hospital,Capital Medical University from January 2014 to September 2015 and 23 age-and sex-matched healthy controls(NC group).All participants underwent the neurocognitive tests including M MSE,MoCA and clinical dementia rating(CDR).The subjects were divided into LA with cognitive normal group (CN) (n=11) and LA patients with vascular cognitive impairment-non dementia group(VCIND) (n=23).Functional MRI (fMRI) was employed at resting state.And then,the functional network establishment and small-world network metrics (characteristic clustering coefficient and path length) were computed using graph analytical methods.Results In the range of 0.05 ≤ Kcost ≤ 0.5,the functional networks fitted the definition of small-worldness in LA (CN),LA(VCIND) and NC groups(δ＞1).The Lambda of group LA(CN) and LA (VCIND) were smaller than that of NC group at each threshold,and more closing to 1.The gamma of group LA(CN) were higher than that of NC group at each threshold.While the gamma of group LA(VCIND)were lower than that of NC group at each threshold.The sigma of group LA(CN) were higher than that of NC group at each threshold.Conclusion The LA patients exhibit abnormal small-world network properties.And compared with HCs,small world properties in LA (CN) patients have been increased,while that in LA (VCIND) patients have been reduced,which manifested that the altered topological properties may be responsible for cognitive dysfunction in LA patients.