轻度和中度阿尔茨海默病海马萎缩的磁共振成像研究

Study of hippocampal atrophy in mild and moderate Alzheimer′s disease by magnetic resonance imaging

目的 探讨轻、中度阿尔茨海默病 (AD)患者海马萎缩特征及其早期诊断的价值。方法对 34例轻、中度AD患者 (AD组 )和 30名正常对照者 (对照组 )的磁共振成像 (MRI)反映的海马结构体积变化进行比较 ,应用受试者特征曲线 (ROC)方法计算海马结构体积 ,作为轻、中度AD临床诊断指标的阈值并评价其价值。结果 AD组的海马结构体积 [(2 .1± 0 .5 )cm3]较对照组 [(3 .2± 0 .4)cm3]减少(P <0 .0 1)。AD组海马结构体积与对照组的重叠率为 12 % ,轻度AD患者的该重叠率为 17% ;以对照组海马结构体积均值和标准差为参照 ,轻度AD患者减少了 1.8个标准差 ,中度AD患者减少了 3.2个标准差。对照组和AD组的海马结构体积均存在增龄减少的现象 ,但AD组的这种特征更为明显(P <0 .0 5 )。以海马结构体积 2 .7cm3 作为诊断阈值最佳 ,敏感度为 88% ,特异度为 93%。结论 MRI的海马萎缩体积测定可作为诊断 (尤其在早期 )

Objective To investigate the features of hippocampal atrophy (HA) by MRI in mild moderate AD (Alzheimer′s disease) patients and its values as an early diagnostic marker for AD. Methods There were 34 mild moderate AD patients and 30 normal controls in the study, and the differences of the hippocampal volume by MRI between the mild moderate patients and the controls were studied. By ROC (receiver operating characteristic curve) method, the cut off point of the hippocampal volume was calculated as an early diagnostic marker for AD and its values were estimated.Results The volume of hippocampus of the AD patients was significantly less than that of the controls ( P <0.01), 17% of the mild AD patients was in the range of the control, and so did 12% of the mild moderate AD; The relative mean hippocampal volume of AD to the control were as follows: in the mild group the mean volume of hippocampus = the mean volume of hippocampus of control -1.8 standard deviation and in the moderate AD group, the volume of hippocampus = the volume of hippocampus of controls -3.2 standard deviations. The hippocampal volume in both of the AD and the control groups decreased with age, but the speed of decreasing of AD was faster ( P <0.05). The best cut off point of hippocampal volume, as a diagnostic marker, was 2.7 cm 3 with the sensitivity of 88% and specificity of 93%.Conclusion MRI based HA could effectively differentiate the mild moderate AD patients from the normal subjects. HA detected by MRI could be regarded as a valuable marker in making clinical diagnosis of AD (especially in its early stage).