脑白质疏松症患者早期认知功能损害与弥散张量成像的相关性研究

Early cognitive impairment in patients with leukoaraiosis and its relation with diffusion tensor imaging

目的分析脑白质疏松症（LA）患者早期认知功能损害的特点和各感兴趣区磁共振弥散张量成像（DTI）的各向异性分数ffA）值变化．并探讨LA患者FA值与认知功能损害的相关性。方法选取山西省人民医院神经内科自2015年8月至2016年10月收治的慢性缺血性LA患者38例（病例组）和健康老年人20例（健康对照组），均进行全面的认知功能测评及MRI、DTI检查，比较2组受试者认知功能、脑内感兴趣区FA值及轻度、中度、重度缺血性LA患者感兴趣区FA值的不同，分析病例组患者各感兴趣区FA值与认知功能的相关性。结果与健康对照组比较，病例组患者简易智能精神状态量表（MMSE）、蒙特利尔认知评估量表（MoCA）评分较低，Stroop色词干扰测验C部分（StroopC）用时较长、词语流畅性测验（VFT）、数字广度（DS）倒序、韦氏儿童智力量表（WISC-CR）词语相似性测验、听觉词语学习测验（AVLT）、画钟试验、积木测试得分较低，连线测验A部分（TMTA）、Stroop色词干扰测验B部分（StroopB）m时较长，差异有统计学意义（P〈O．05）。与健康对照组比较，病例组患者双侧侧脑室前角、左侧额上回、左侧额下回、双侧额叶眶回、右侧颞叶深部白质、右侧扣带回、胼胝体膝部的FA值下降，差异有统计学意义（P〈O．05）；且轻度、中度、重度LA患者上述感兴趣区FA值依次降低，差异均有统计学意义（P〈0．05）。相关性分析显示，病例组患者AVLT得分与左侧侧脑室前角、左侧额叶眶回、右侧额叶眶回、右侧颢叶深部白质、右侧扣带回、胼胝体膝部FA值呈正相关关系（P〈O．05），与左侧额下回FA值呈负相关关系（P〈O．05）；TMTA用时与右侧侧脑室前角FA值呈负相关关系（P〈0．05），StroopB用时与右侧颞叶深部白质FA值呈负相关关系（P〈0．05），StroopC用时与左侧额叶眶回、右侧颞叶深部白质、右侧扣带回、胼胝体膝部FA值呈负相关关系（P〈0．05），积木测试得分与左侧额叶眶回、右侧颞叶深部白质、胼胝体膝部FA值呈正相关关系（P〈0．05）。结论LA患者早期认知功能损害、FA值下降，FA值与认知功能损害程度相关。DTI有助于诊断LA患者早期认知功能损害。

Objective To analyze the characteristics of early cognitive impairment in leukoaraiosis （LA） patients and fractional anisotropy （FA） changes by diffusion tensor imaging （DT/） in various regions of interest （ROIs）, and explore the relationship between FA values and cognitive impairment. Methods A total of 38 chronic ischemic LA patients, admitted to our hospital from August 2015 to August 2016, and 20 healthy elderly controls were chosen in our study. Comprehensive assessment of cognitive functions, and MRI and DTI examinations were performed in subjects from these two groups. The cognitive functions, and FA values in ROIs were compared between the two groups; the FA values in ROIs of mild, moderate, and severe ischemic LA patients were compared. The correlations between FA values in ROIs and cognitive functions in LA patients were analyzed. Results As compared with the healthy control group, the patient group had significantly lower Mimi Mental State Examination （MMSE） and Montreal Cognitive Assessment （MoCA） scores, statistically longer time of Stroop test C, lower scores of verbal fluency test （VFT）, digit span （DS）-inverted sequence, word similarity test in Chinese Revision of Wechsler Intelligence Scale for Children （WISC-CR）, auditory verbal learning test （AVLT）, clock drawing test and block testing, and significantly longer time of Trail Marking Test A （TMTA） and Stroop test B （P〈0.05）, suggesting that the overall cognitive function, executive function, memory, visual-spatial ability, information processing capability of LA patients decreased greatly. Significantly decreased FA values in bilateral anterior horn of lateral ventricle, left superior frontal gyrus, left inferior frontal gyrus, bilateral frontal orbital gyrus, right deep temporal lobe, right cingulate gyrus, and genu of corpus callosum in the LA patient group were noted as compared with those in the control group （P〈0.05）. In mild, moderate and severe LA patients, the FA values of these ROIs decreased in turn, with statistically significant differences （P〈0.05）. In the LA patient group, correlation analysis showed that the scores of auditory verbal learning test were positively correlated with FA values in the brain regions of left anterior horn of lateral ventricle, bilateral frontal orbital gyrus, deep white of right temporal lobe, fight cingulate gyrus, and genu of corpus callosum （P〈0.05）, and negatively correlated with FA values in left inferior frontal gyrus （P〈0.05）; the scores of trail making test A were negatively related with FA values in right anterior horn of lateral ventricle （P〈0.05）; the Stroop test B scores were negatively correlated with FA values in deep white matter of the right temporal lobe （P〈0.05）; the Stroop test C scores were negatively related with FA values in left orbital frontal cortex, deep white of right temporal lobe, right cingnlate gyrus, and genu of corpus callosu （P〈0.05）; and the block testing scores were positively related with FA values in left frontal orbital gyrus, right temporal lobe deep, and genu of corpus callosu （P〈0.05）. Conclusions The early cognitive impairment and decreased FA values are noted in LA patients. FA values are related to cognitive impairment. DTI contributes to diagnose early cognitive impairment in LA patients.