缺血性脑血管病患者皮层下灰白质微结构变化及其与认知功能的相关性

Diffusion characteristics of subcortical structures in patients with subcortical ischemic vascular disease and its correlation to cognitive function

目的探讨皮层下缺血性脑血管病(SIVD)患者常规MRI上看似正常的白质(NAWM)和灰质(NAGM)水分子弥散特征及其与认知功能的关系。方法对46例SIVD患者和34例健康自愿者行常规MRI和DTI检查,比较两组间皮层下NAWM区和NAGM区表观弥散系数(ADC)和部分各向异性(FA)的差异,分析SIVD患者皮层下灰白质微结构变化与整体认知功能的相关关系。结果④SIVD组NAGM区、侧脑室前角和半卵圆中心NAWM区ADC值显著大于对照组(P<0.05),半卵圆中心NAWM区FA值则显著低于对照组(P<0.05);④SIVD组侧脑室前角NAWM区的ADC值随脑白质病分级的增加而增加,而FA值随之降低;④控制年龄后,侧脑室后角NAWM区、半卵圆中心(NAWM和脑白质病区)、尾状核头及丘脑的ADC值与简易精神状态检查量表呈显著负相关;侧脑室前角NAWM区和半卵圆中心脑白质病内FA值与简易精神状态检查量表呈显著正相关。结论在SIVD患者中,常规MRI上看似正常的皮层下灰质和白质水分子弥散已发生异常,而且与SIVD患者的整体认知功能有关。

Objective To explore the diffusion-tensor imaging（DTI） characteristics of normal-appearing white matter（NAWM） and normal-appearing gray matter（NAGM） on conventional magnetic resonance imaging（MRI） in patients with subcortical ischemic vascular disease（SIVD） and examine the relation of such features with the general cognitive function of the patients.Methods DTI was performed in 46 SIVD patients and 34 age-matched control subjects with normal MRI findings.The apprarent diffusion coeeficient（ADC） and fractional anisotropy（FA） were measured within the regions of white matter lesions（WMLs）,NAWM and NAGM.All the subjects were examined by neurologists with MMSE and clinical neurologic examination.Results Compared with normal controls,SIVD subjects showed increased ADC values in the subcortical NAGM and NAWM in anterior periventricular and centrum semiovale,with decreased FA values in the caudate nucleus,thalamus and centrum semiovale.An increased severity of the WMLs was associated with increased ADC and decreased FA in the NAWM of SIVD patients.After controlling for age,the ADC in the NAWM of the posterior periventricular,NAWM and WMLs in the centrum semiovale,caudate nucleus and thalamus showed significant inverse correlations to MMSE;FA values in NAWM of the anterior periventricular and WMLs of the centrum semiovale were positively correlated to MMSE.Conclusion In SIVD patients,the NAWM and NAGM regions shown by MRI contain diffusion abnormalities,and these abnormalities shown by DTI are significantly correlated to the general cognitive function of the patients.