Abstract:

Objective To study the changes of corpus callosum network connectivity in leukoaraiosis (LA) patients by diffusion tensor imaging (DTI), and investigate the association between this change and cognitive impairment. Methods This study is a single-center prospective cohort study. The subjects were divided into two groups: (1) LA group (n =30) who had extensive LA according to Fazekas scale, including two subgroups with normal cognition and mild cognitive impairment; (2) Control group (n =20) who had normal brain magnetic resonance images (MRI). All subjects underwent baseline examinations, including a questionnaire about the risk factors of cerebrovascular disease, blood tests, cognitive assessments and 3.0T brain MRI scan, including fluid attenuated inversion recovery (FLAIR) and DTI sequences. DTI datum were processed by PANDA software and the quantitative values about fractional anisotropy (FA) and mean diffusivity (MD) in corpus callosum were extracted. The relationship between cognitive impairment and the changes of FA & MD was analyzed by Pearson’s correlation analysis. Results There were no significant differences of the baseline levels in two group, including sex, age, education, risk factors of cerebrovascular disease and some blood biochemical indexes, P >0.05.

The scores about Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were significantly lower in LA group than in control’s, P values were 0.002 and 0.008 respectively. The FA values in the genu (P =0.000), body (P =0.000) and splenium (P =0.026) of corpus callosum were significantly lower in LA group than in control’s, but the MD’s were just to the contrary, P values were 0.013, 0.006 and 0.007 respectively. There was positive relation between cognitive impairment and lower FA value of corpus callosum, and the correlation coefficients declined gradually from the genu (r =0.78) to splenium (r =0.41) of corpus callosum. Conclusion The changes of network connectivity in corpus callosum exist in LA patients, and FA decline in corpus callosum is positively related to cognitive impairment.

Key words: Leukoaraiosis; Diffusion tensor imaging; Corpus callosum; Network connectivity; Cognitive impairment

摘要：

目的 通过弥散张量成像（diffusion tensor imaging，DTI）研究脑白质疏松（leukoaraiosis，LA）患者胼 胝体网络连接性改变，并探讨其与认知功能损害的关系。 方法 本研究为前瞻性单中心研究。纳入30例法泽卡斯量表（Fazekas scale）评分为2～3级的LA患 者及20例头部磁共振成像正常的对照组。依据是否存在认知功能损害将LA组再分为认知正常与轻 度认知功能损害2个亚组。所有被研究对象均进行脑血管危险因素登记、血液生化检查、认知功能 评估筛查及3.0T头部磁共振成像检查及DTI检查。认知评估采用中文版蒙特利尔认知评估（Montreal Cognitive Assessment，MoCA）量表及简易智力状况检查（Mini-mental State Examination，MMSE）量表。使 用PANDA软件处理DTI数据，提取胼胝体膝部、体部及压部的部分各向异性（fractional anisotropy，FA） 和平均扩散系数（mean diffusivity，MD）数值。采用Pearson相关分析研究DTI数据变化与认知功能损害 的关系。 结果 LA组与对照组的性别、年龄、受教育情况、脑血管病常规危险因素及血生化之间差异无 显著性，P >0.05。LA组的MMSE及MoCA分值低于对照组，P值分别为0.002和0.008。LA组胝体膝部 （P =0.000）、体部（P =0.000）、压部（P =0.026）3个部位的FA值均低于对照组，而MD值高于对照组，P 值分别为0.013、0.006及0.007。LA组MMSE及MoCA分值降低与胼胝体膝部、体部、压部的FA下降均成 正相关，但相关系数从膝部（r =0.78）到压部（r =0.41）呈现逐渐递减趋势。 结论 LA存在胼胝体网络连接性改变，胼胝体FA下降与认知功能损害密切相关。

关键词: 脑白质疏松; 弥散张量成像; 胼胝体; 网络连接性; 认知功能损害