中文摘要：

目的利用Meta分析评价和比较氟脱氧葡萄糖-正电子发射断层显像（nuomdeoxyglucose—positron-emission tomography，FDG—PET）、单光子发射计算机断层显像（single—photon emission tomography，SPECT）及结构性磁共振成像（magnetic resonance imaging，MRI）这三种临床常用的神经显像方法对轻度认知障碍（mild cognitive impairment，MCI）预后的预测价值。方法在MEDLINE数据库中检索1990年1月至2009年4月发表的英文文献。制定纳入标准对文献进行筛选以保证纳入研究的同质性。对符合标准的所有研究结果进行Meta分析和Meta回归分析。估计和比较三种显像方法的加权灵敏度、特异性、似然比（1ikelihood ratios，LR）和接受者工作特征（receiver operating characteristic，ROC）曲线。利用Meta回归和亚组分析方法探讨纳入研究间异质性的来源。结果20篇文献符合全部纳入标准，含794例MCI患者。三种方法的比值比（oddsratio，OR）和阳性LR值的比较结果提示，FDG—PET对MCI预后的预测能力显著高于其他两种显像方法；然而，三种预测方法的灵敏度、特异性和阴性LR值并无显著性差异。FDG—PET、SPECT和MRI的Q^＊值分别是0．89、0．79和0．80。Meta回归分析发现，logOR只与显像方法的选择存在回归关系。结论FDG—PET对MCI患者预后的预测能力略优于SPECT和MRI，而后两者的预测能力没有显著差异。

英文摘要：

Objective To evaluate the values of different brain imaging including FDG-PET, SPECT and MRI in predicting the conversion from mild cognitive impairment （ MCI ） to Alzheimer disease in patients with MCI. Methods Relevant studies were identified through MEDLINE search from January 1990 to April 2009. Meta-analysis and meta-regression were conducted on brain image data from eligible studies. The weighted summary sensitivities, specificities, likelihood ratios （LRs） , and summary receiver operating characteristic curves of each imaging technique were calculated and then compared. Results Twenty eligible studies were included, with a total of 794 patients. FDG-PET performed statistically better than either SPECT or MRI in terms of LR ＋ and odds ratio （OR）. However, there were no significant differences in sensitivity, specificity, and LR among those three brain images. The Q ＊ indexes for FDG-PET, SPECT, and structural MR were 0. 89, 0. 79, and 0. 80, respectively. Meta-regression only revealed that log OR was associated with selection of brain imaging. Conclusions The present recta-analysis suggest that FDG-PET performs slightly better than SPECT and structural MR imaging in the prediction of conversion of MCI to AD in patients with MCI.