18F-FDG Is a Superior Indicator of Cognitive Performance Compared to 18F-Florbetapir in Alzheimer's Disease and Mild Cognitive Impairment Evaluation: A Global Quantitative Analysis.

Background: F-18-Fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET) and F-18-florbetapir PET are approved neuroimaging biomarkers for the Alzheimer's disease (AD) and mild cognitive impairment (MCI). Objectives: This study aims to compare the efficacy of F-18-FDG and F-18-florbetapir PET at evaluating the cognitive performance of patients with AD, MCI, and normal controls (NC). Methods: 63 subjects (36 male/27 female, mean age = 68.3) including 19 AD, 23 MCI, and 21 NC underwent F-18-FDG and F-18-florbetapir PET imaging. A global quantification approach was applied on supratentorial, frontal, parietooccipital, temporal, and cerebellar brain regions by calculating the global SUV mean ratios (GSUVr) as the weighted average of all regional SUV mean. F-18-FDG and F-18-florbetapir GSUVr of each region were subsequently correlated with the Mini-Mental State Examination (MMSE). Results: Subjects were studied in five categories as NC, MCI patients, AD patients, MCI and AD patients grouped together (MCI/AD), and a group including all the subjects (NC/MCI/AD). Both F-18-FDG and F-18-florbetapir could successfully detect subjects with dementia (p < 0.001). Studied in all regions and groups, the correlation analysis of F-18-FDG GSUVr with MMSE scores was significant in more regions and groups compared to that of F-18-florbetapir. We also demonstrated that the correlation of F-18-FDG GSUVr with MMSE is stronger than that of F-18-florbetapir in the supra-tentorial and temporal regions. Conclusions: This study reveals how F-18-FDG-PET global quantification is a superior indicator of cognitive performance in AD and MCI patients compared to F-18-florbetapir PET. Accordingly, we still recommend F-18-FDG-PET over amyloid imaging in the evaluation for AD and MCI.