MRI线性测量局部脑萎缩对早期阿尔兹海默病的诊断意义

目的评价ＭＲＩ线性测量脑萎缩程度对阿尔兹海默病（Ａｌｚｈｅｉｍｅｒｄｉｓｅａｓｅ，ＡＤ）患者的早期诊断价值。方法应用ＭＲＩ线性定量测量对３０例轻度痴呆的ＡＤ患者、２０例多发脑梗塞性痴呆（ＭＩＤ）和２０名正常老年人进行局部额叶（双额指数、额叶半球间宽度）、中颞叶（海马钩回间距、中颞叶最小厚度）及海马结构（海马高度、脉络膜裂宽度、海马脑干间距及颞角宽度）等指标测量。结果颞角宽度指标是区别ＡＤ患者与ＭＩＤ患者及正常老年人的最敏感的指标；其敏感性达９０％，特异性达８５％。如结合脉络膜裂宽度、海马高度、海马与脑干间距及海马钩回间距，其敏感性达９３％，特异性达９５％。结论ＭＲＩ线性定量测量局部海马萎缩能够作为早期诊断ＡＤ的准确可靠性指标之一。

MRI linear measures of brain regional atrophy in mild Alzheimer disease

Objective To assess the sensitivity and specificity of linear measures of brain atrophy in the diagnosis of Alzheimer disease (AD) in the early stages. Methods Linear measures of regional frontal lobe (bifrontal index, interhemispheric fissure width), medial temporal lobe (interuncal distance, minimal thickness of the medial temporal lobe), and hippocampus (hippocampal height, width of the choroid fissure, width of the temporal horn and distance between the hippocampus and brain stem), indicating the indeces of brain atrophy were made on the magnified MRI obtained in 30 patients with mild AD, 20 patients with multi infarct dementia (MID) and 20 control subjects. Results The measure with the best sensitivity in discriminating AD patients from MID and control subjects was the width of the temporal horn, the sensitivity being 90% and the specificity being 85%. A compound measure of the width of the temporal horn, the width of the choroid fissure, the interuncal distance, the hippocampal height and the distance between the hippocampus and brain stem could discriminate the patients with mild AD from MID and the control subjects with 93% sensitvity and 95% specificity. Conclusion Linear measures of hippocampal atrophy can be of use in the routine diagnosis of AD, even in its early stages.