孟明　　董春波　　宋清伟　　徐斌　　陈建文　　赵莉

弥散张量成像对阿尔茨海默病脑白质改变的评价

孟明*董春波△宋清伟※徐斌※陈建文△赵莉△

目的 分析阿尔茨海默病（Alzheimer's disease，AD）脑白质结构改变及与认知功能的关系。方法对37例AD组和32例对照组行简易精神状态量表（mini-mental State examinationn，MMSE）评估和DTI扫描。采用基于全脑体素分析法对两组全脑白质各向异性（fractional anisotropy，FA）图进行比较，采用t检验分析FA值差异，并评估AD组MMSE评分与FA值相关性。结果 AD患者出现FA值下降区域广泛分布在右侧额叶、颞叶、枕叶、丘脑及双侧扣带回、胼胝体、楔前叶、顶叶下回、顶下小叶、缘上回及海马旁回（其中P＜0.001，未经校正的P值）；当使用经FWE校正的P＜0.05后，AD患者右侧扣带回、左侧胼胝体、颞叶下回及双侧顶叶下回、额叶下回、楔前叶区域FA值较对照组显著下降。AD患者FA值下降与MMSE量表评分呈正相关，（P＜0.001，未经校正）。结论AD患者存在特定脑区白质结构改变，并与认知功能损害程度呈正相关。

阿尔茨海默病白质弥散张量成像认知功能

【Abstract】Objective To study the microscopic changes of white matter and the relationship between white matter changes and cognitive impairment in Alzheimer's disease（AD）using voxel-based analysis of DTI.Methods Thirty-seven patients with probable AD，and 32 normal controls（NC）were all examined by MMSE scores，and underwent a diffusion tensor imaging.The value of FA changes and the correlations between FA and MMSE scores were investigated.Results FA reduction was detected in the right frontal，temporal and parietal lobes as well as the thalamus，the bilateral cingulum，corpus callosum，precuneus，inferior parietal lobule，inferior patieto gyrus，supramaginal gyrus and hippocampus in AD.FA values in the right cingulum，left corpus callosum，left inferior temporal gyrus and the bilateral inferior parietal lobule，inferior patieto gyrus and precuneus were significantly decreased in AD than in the health control groups（P＜0.05，FWE corrected）.There was a positive correlation between the values of FA and MMSE scores（P＜0.001，uncorrected）.Conclusion AD patients have significant reduction of FA values in the specific regions.There is a positive correlation between white matter changes and impairments of cognitive function.

【Key words】Alzheimer disease Diffusion tensor imaging White matter Cognitive function

近年来，越来越多研究发现阿尔茨海默病（Alzheimer's disease，AD）患者脑白质微细结构的病理性改变［1-2］。部分各向异性值（fractional anisotropy，FA）作为弥散张量成像（diffusion tensor imaging，DTI）的重要评价参数能够对白质完整性进行整体评估［3］。基于DTI定量分析脑白质常见方法有多种，其中ROI法依赖操作者主观性较强、可重复性较差、耗费时间较多［4］；TBSS法易受到容积效应及噪声影响，不适合检测细小纤维束，对纤维交叉部位检测的准确性也有待考察［5］；本研究釆用的VBA法客观性强，对参数敏感且可重复性好，从全脑角度探究脑区间相互联系，可以检测出潜在脑区异常。……