In Vivo Imaging of Amyloid Deposition in Alzheimer Disease Using the Radioligand 18 F-AV-45 (Flobetapir F 18)

An open-label, multicenter brain imaging, metabolism, and safety study of (18)F-AV-45 was performed on 16 patients with AD (Mini-Mental State Examination score, 19.3 +/- 3.1; mean age +/- SD, 75.8 +/- 9.2 y) and 16 cognitively healthy controls (HCs) (Mini-Mental State Examination score, 29.8 +/- 0.45; mean age +/- SD, 72.5 +/- 11.6 y). Dynamic PET was performed over a period of approximately 90 min after injection of the tracer (370 MBq [10 mCi]). Standardized uptake values and cortical-to-cerebellum standardized uptake value ratios (SUVRs) were calculated. A simplified reference tissue method was used to generate distribution volume ratio (DVR) parametric maps for a subset of subjects.

Valid PET data were available for 11 AD patients and 15 HCs. (18)F-AV-45 accumulated in cortical regions expected to be high in Abeta deposition (e.g., precuneus and frontal and temporal cortices) in AD patients; minimal accumulation of the tracer was seen in cortical regions of HCs. The cortical-to-cerebellar SUVRs in AD patients showed continual substantial increases through 30 min after administration, reaching a plateau within 50 min. The 10-min period from 50 to 60 min after administration was taken as a representative sample for further analysis. The cortical average SUVR for this period was 1.67 +/- 0.175 for patients with AD versus 1.25 +/- 0.177 for HCs. Spatially normalized DVRs generated from PET dynamic scans were highly correlated with SUVR (r = 0.58-0.88, P