Simplified methods of acquisition and quantification would facilitate the use of synaptic density imaging in multicenter and longitudinal studies of Alzheimer disease (AD). We validated a simplified tissue-to-reference ratio method using SUV ratios (SUVRs) for estimating synaptic density with [¹¹C]UCB-J PET. Methods: Participants included 31 older adults with AD and 16 with normal cognition. The distribution volume ratio (DVR) using simplified reference tissue model 2 was compared with SUVR at short scan windows using a whole-cerebellum reference region. Results: Synaptic density was reduced in AD participants using DVR or SUVR. SUVR using later scan windows (60–90 or 70–90 min) was minimally biased, with the strongest correlation with DVR. Effect sizes using SUVR at these late time windows were minimally reduced compared with effect sizes with DVR. Conclusion: A simplified tissue-to-reference method may be useful for multicenter and longitudinal studies seeking to measure synaptic density in AD.

简化的采集和定量方法将有助于突触密度成像在阿尔茨海默病 （AD） 的多中心和纵向研究中的应用。我们验证了一种使用 SUV 比率 （SUVR） 的简化组织参考比值方法，用于估计 [¹¹C]UCB-J PET 的突触密度。方法：参与者包括 31 名患有 AD 的老年人和 16 名认知正常的老年人。使用全小脑参考区域，将使用简化参考组织模型 2 的分布体积比 （DVR） 与短扫描窗口下的 SUVR 进行比较。结果：使用 DVR 或 SUVR 的 AD 参与者的突触密度降低。使用较晚扫描窗口 （60-90 或 70-90 分钟） 的 SUVR 偏倚最小，与 DVR 的相关性最强。与使用 DVR 的效应大小相比，在这些较晚的时间窗口使用 SUVR 的效果大小最小。结论：简化的组织到参考方法可能有助于寻求测量 AD 突触密度的多中心和纵向研究。