脑β-淀粉样蛋白PET显像模型分析对AD与MCI的诊断价值

目的 探讨脑β-淀粉样蛋白（Aβ）PET显像模型分析对阿尔茨海默病（AD）与轻度认知功能障碍（MCI）的鉴别诊断价值。方法 纳入32例认知功能障碍受试者,经临床检查明确AD或MCI诊断,对其静脉注射显像剂¹⁸F-AV-45 2.96~4.44 MBq/kg,行心脏和头部PET/CT扫描。测得患者左心室及脑部感兴趣区域（ROI）不同时间点的比活度拟合曲线,通过Logan模型计算¹⁸F-AV-45代谢率K值。采用Mann-Whitney U检验比较AD与MCI患者代谢率K值的差异,使用受试者工作特征（ROC）曲线评估Logan模型的诊断效能。结果 AD、MCI患者大脑皮质Aβ沉积程度不同,应用Logan模型代谢率K值可鉴别两者,AD患者代谢率K值为3.96（2.66,4.26）,高于MCI患者代谢率K值2.62（1.41,2.96）（P < 0.05）。代谢率K值ROC曲线分析获得最佳诊断阈值为3.23,其诊断灵敏度为100%、特异度为58.33%,ROC曲线下面积为0.781（Z = -2.350、P < 0.05）。结论 脑AβPET显像Logan模型分析对AD与MCI具有较佳的鉴别诊断效能。

Diagnostic efficiency of Aß protein PET brain imaging model in patients with AD and MCI

Objective To evaluate the diagnostic value of Aβ protein PET brain imaging model in distinguishing patients with Alzheimer's disease （AD） from mild cognitive impairment （MCI）. Methods Thirty-two subjects with cognitive impairment were enrolled in this study. All participants were diagnosed with AD or MCI by clinical examination and underwent ¹⁸F-AV-45 （2.96~4.44 MBq/kg）PET/CT scan（heart and head）. The fitting curves of specific activity of left ventricle and region of interest （ROI） at different time points were delineated, and then the metabolic rate K was calculated by Logan model. The difference in metabolic rate K value was compared between AD and MCI groups by using Mann-Whitney U test. The diagnostic efficiency of Logan model was evaluated by the receiver operator characteristic （ROC） curve. Results The degree of Aβ protein deposition in the cerebral cortex of AD and MCI patients was different. AD and MCI patients could be distinguished with the K value of Logan model. The K value in the AD group was 3.96（2.66, 4.26）, significantly higher than 2.62（1.41, 2.96） in the MCI group （P < 0.05）. According to ROC curve analysis, the optimal diagnostic threshold of K value was 3.23, the diagnostic sensitivity was 100%, the specificity was 58.33%, and the area under ROC curve （AUC） was 0.781 （Z = -2.350, P < 0.05）, respectively. Conclusion Aβ protein PET imaging with Logan model has high diagnostic efficacy in distinguishing AD from MCI.