磁共振弥散张量成像对阿尔茨海默病脑白质损害的评估及鉴别价值

The Value of Diffusion Tensor Imaging in Evaluating the Changes of Microstructural Integrity of White Matter in Alzheimer's Disease Patients

目的:应用MR弥散张量成像(DTI)观察阿尔茨海默病(AD)患者脑白质纤维束完整性。方法:健康老年志愿者为对照组(NC)组、遗忘型轻度认知障碍(aMCI)组、AD组和皮质下缺血性血管性痴呆(SIVD)组各20例,行常规MRI和DTI扫描后,测定相同感兴趣区(ROI)的各向异性分数(FA)值和表观扩散系数(ADC)值进行比较。结果:与NC组比较, AD组前额叶、颞叶、海马等部位FA值降低,颞叶、海马等部位ADC值升高(P<0.05);aMCI组仅扣带束FA值降低,与AD组比差异有统计学意义(P<0.05);SIVD组下额枕束等部位FA值下降,ADC值升高,与AD组比较差异有统计学意义(P<0.05)。结论:DTI可以用来评估白质纤维束完整性,AD组白质损害甚于aMCI患者;扣带束FA值可以作为aMCI患者筛查的指标;根据受累部位不同可对SIVD与AD进行鉴别。

Aim：To study the integrity of white matter（WM） fiber tracts in patients with Alzheimer＇s disease （AD）（P0.05） using diffusion tensor imaging（DTI）.Methods：Four groups were identified and compared. They are normal control（NC） group,amnestic mild cognitive impairment（aMCI） group,AD group and subcortical ischemic vascular dementia（SIVD） group,20 cases in each group.After routine MRI and DTI were completed,fractional anisotropy（FA） and apparent diffusion coefficient（ADC） values were measured and compared on regions of interest（ROI）.Results：Compared with NC group,FA values of anterior frontal lobe, temporal lobe,hippocampus,etc.were lower（P0.05）,and ADC values of temporal lobe and hippocampus were higher in AD group.Compared with AD group,FA values of cingulate fasciculus in aMCI group were lower（P0.05）;FA values of inferior-frontooccipital fascicles,etc.were lower and ADC values were higher in SIVD group（P0.05）.Conclusion：DTI can be used to estimate the integrity of white matter（WM）.The degree of WM impairment in AD group is more serious than in aMCI group.The FA values of cingulate fasciculus may be used as a screening test for aMCI patients.It may provide an objective way to differentiate SIVD and AD according to the different regions involved.