轻度认知障碍进展为阿尔茨海默病过程中脑灰质体积特征改变的MRI研究

Voxel-based MRI study on brain gray matter of patients with mild cognitive impairment converting to Alzheimer disease

目的探讨轻度认知障碍(MCI)患者进展为阿尔茨海默病(AD)过程中,脑灰质(包括皮层和灰质核团)萎缩发生的部位及其进展趋势。方法自ADNI数据网站下载15例2年内进展为AD的MCI患者和14名健康老年人的MR结构图像和MMSE评分结果。15例进展为AD的MCI患者基线时间(随访开始时间)为MCI组,进展为AD时作为AD组。14名健康老年人为对照组(基线时间为NC0组,2年后为NC1组)。利用SPM 8对MCI组、AD组和对照组的全脑灰质体积进行基于体素的统计学比较。结果与NC0组比较,MCI组和AD组双侧内侧颞叶灰质体积萎缩,且AD组左侧尾状核头部、左侧丘脑前部体积萎缩;NC1组左侧海马头部、左侧中央后回灰质体积萎缩。结论 MCI进展为AD过程中,脑灰质萎缩主要发生在与记忆相关的内侧颞叶,全脑灰质萎缩存在左侧半球严重于右侧半球的发展趋势,在边缘系统内部呈现自海马向杏仁核、丘脑的蔓延趋势。

Objective To evaluate the distribution and development trend of brain gray matter atrophy in the process of conversion from mild cognitive impairment（MCI）to Alzheimer disease（AD）.Methods Fifteen patients with MCI converting to AD among 2years and 14 normal elderly subjects were recruited from the ADNI（Alzheimer disease Neuroimaging Initiative）.All subjects were examined with structural MRI.Their change in cognitive funciton was evaluated by the minimental state examination（MMSE）.Fifteen patients with MCI at baseline were selected as MCI group,and the 15 patients when converting to AD were observed as AD group.Fourteen normal subjects were selected as normal controls.The normal subjects at baseline were named as NC0 group,24months later named as NC1 group.The atrophy of gray matter was assessed by means of statistical parametric mapping（SPM）.Results Compared with NC0 group,MCI group and AD group showed significant atrophy of bilateral medial temporal lobe（left hippocampus＇ head and body,bilateral parahippocampal gyrus and left amygdala）.In AD group,significant atrophy of gray matter was found in left caudate head and left anterior thalamus too.Compared with NC0 group,significant atrophy of gray matter in NC1 group was found in left hippocampus＇ head,bilateral parahippocampal gyrus and left posterior central gyrus.Conclusion Gray matter atrophy occurs mainly in the memory-related medial temporal lobe（hippocampus,parahippocampal gyrus and amygdala）in the progression of MCI converting to AD.The appearance for marked gray matter loss in the left hemisphere is observed.The trend of spreading from hippocampus to other regions（amygdala and thalamus）within the limbic system is found in the progression.