皮层下缺血性脑血管病患者弥散张量成像中脑微结构变化与整体认知功能及执行功能的独立相关性研究

Independent correlations of cerebral microstructural changes on DTI to general cognitive function and executive function in patients with subcortical ischemic vascular disease

目的探讨皮层下缺血性脑血管病(sIVD)患者弥散张量成像(DTI)皮层下灰白质微结构变化与整体认知功能和执行功能的独立相关性。方法 66例SIVD患者(其中认知障碍非痴呆组30例,认知功能正常组36例)行常规核磁共振成像(MRI)和DTI检查,采用简易精神状态量表(mini-mental state examination,MMSE)和画钟试验(cDT)分别评价其整体认知功能和执行功能。比较两组患者常规MRI上脑形态学指标及皮层下灰白质的DTI参数,分析与SIVD患者认知功能相关的影像学独立相关因素。结果与认知功能正常(NCI)组相比较,认知障碍非痴呆(VCIND)组侧脑室周围白质病变(PVLs)分级显著增加(P<0.01),半卵圆中心看似正常白质(NAWM)区和白质病变(WMLs)区、壳核及丘脑的表观弥散系数(ADC,值显著增加(P<0.01),侧脑室前角NAWM、尾状核、壳核及丘脑的部分各向异性(FA)值显著降低(P<0.05)。控制年龄和受教育程度后,PVLs、半卵圆中心NAWM区和WMLs区ADC值、壳核ADC值与MMSE呈显著负相关(P<0.01);壳核及侧脑室前角NAWM区FA值与MMSE呈显著正相关。脑腔梗数目、侧脑室后角NAWM区及尾状核头部ADC值与CDT呈显著负相关;侧脑室前角NAWM区和丘脑FA值与CDT呈显著正相关。多元逐步回归分析显示半卵圆中心NAWM和WMLs区ADC值与MMSE呈独立负相关;尾状核头ADC值和腔梗数目与CDT呈独立负相关。结论在非痴呆SIVD患者中,半卵圆中心白质结构的完整性是影响SIVD患者整体认知功能的主要因素,且独立于常规MRI上的脑结构改变;尾状核微结构的改变和腔梗的数目是影响SIVD患者执行功能主要因素。

Objective To investigate whether DTI abnormalities in patients with nondemented subcortical ischemic vascular disease（SIVD） are correlated to general cognitive function and executive function independent of conventional MRI parameters.Methods Sixty-six SIVD patients including 30 with cognitive impairment without dementia（VCIND） and 36 with normal cognition（NCI） underwent DTI and cognitive assessment of the general cognitive function and executive function. Conventional MRI parameters and DTI parameters were measured within the white matter lesions（WMLs）,normal-appearing white matter（NAWM） and normal-appearing gray matter（NAGM）.The independent predictors of general cognitive function and executive function in SIVD patients was analyzed.Results NCI and VCIND patients showed significant differences in the periventricular WMLs,ADC valus in NAWM and WMLs of the centrum semiovale,and FA values in NAWM of the anterior periventricular.Except for ADC values of the caudate nucleus,ADC and FA values in the subcortical NAGM showed significant difference between the two groups.After controlling for age and education,PVLs and ADC values in the WMLs and NAWM of the centrum semiovale and putamen,and FA values in the anterior periventricular NAWM,WMLs and putamen showed significant correlations to MMSE;the number of lacunar infarcts,ADC values in posterior periventricular NAWM and caudate nucleus,and FA values in anterior periventricular NAWM and thalamus showed significant correlations to CDT.Multivariate analysis showed independent correlations of the ADC values in WMLs and NAWM of the centrum semiovale to MMSE,and demonstarted correlations of the ADC values of the caudate nucleus and number of lacunar infarcts to CDT.Conclusion In nondemented SIVD subjects,the integrity of the white matter in the centrum semiovale strongly correlates to the general cognition,and the microstructural damage of the caudate nucleus head predicts executive function impairment independent of other MRI variables.