弥散张量成像技术预测遗忘型轻度认知障碍患者向老年性痴呆转化的随访研究

目的:探讨弥散张量成像技术(diffusion tensor imaging,DTI)对遗忘型轻度认知功能障碍(aMCI)向老年性痴呆(AD)转化的预测作用。方法:41例aMCI患者(aMCI组)常规予核磁共振(MRI)和DTI扫描,测定感兴趣区的各向异性分数(fractional anisotropy,FA)和表观扩散系数(apparent diffusion coefficient,ADC),以20名老年健康志愿者作为对照(正常对照组)并随访1~3年。结果:与正常对照组比较,aMCI组41例患者中有22例扣带束FA基线值偏低(P0.05),随访1~3年后,其中有19例转化为AD;另外19例扣带束FA值正常的aMCI患者只有2例转化为AD。与非转化AD者比较,AD转化者前额叶、颞叶、海马、下额枕束、胼胝体膝部和扣带束等部位FA值降低(P均0.01),颞叶、海马等部位ADC值升高(P均0.05)。结论:DTI技术具有预测aMCI向AD转化的作用,aMCI患者扣带束FA值低可能是aMCI向AD转化的敏感指标。

A follow-up study using diffusion tension imaging to predict the conversion to Alzheimer disease in patients with amnesic type mild cognitive impairment

Objective：To evaluate the predictive role of diffusion tensor imaging（DTI）in patients with amnesic type mild cognitive impairment（aMCI）converting to Alzheimer′s disease（AD）. Method：Forty-one aMCI patients（aMCI group）and 20 healthy volunteers（normal control group）as controls were recruited in this study. After routine magnetic resonance and DTI scans were completed,fractional anisotropy（FA）and apparent diffusion coefficient（ADC）values were measured and compared on different regions of interest（ROI）. All of the participants were follow-up for 1-3 years. Results：Compared to controls,22 subjects in the aMCI group had low-er FA values in the cingulate fasciculus at baseline（P ﹤ 0. 05）. 19 cases of them converted to AD the follow-up. Only 2 of the other 19 aMCI patients with normal FA values converted to AD. Compared to non-AD converters, AD converters showed lower FA values in the anterior frontal lobe,temporal lobe,hippocampus,inferior fronto-occipital fascicles,corpus callosum genu and cingulate fasciculus（all P ﹤ 0. 01）,and higher apparent diffusion coefficient values in the temporal lobe and hippocampus（all P ﹤0. 05）. Conclusion：DTI scans provide a pre-dictive effect on the clinical conversion from aMCI to AD. For aMCI patients,lower FA value in the cingulate fasciculus may be a sensitive indicator of aMCI conversion to AD.