Brain [F-18]Fddnp Binding And Glucose Metabolism In Advanced Elderly Healthy Subjects And Alzheimer'S Disease Patients

Background: Positron emission tomography (PET) imaging of brain amyloid (A beta) and neurofibrillary tangle (NFT) load is a candidate biomarker of Alzheimer's disease (AD).Objectives: To compare brain A beta and NFT load and glucose metabolism in advanced elderly (70 years and older) patients with AD and healthy controls (HCs) by PET with [F-18]FDDNP and [F-18]FDG.Methods: Seven AD patients (mean +/- SD age 79.3 +/- 3.6 y, Mini-Mental State Examination (MMSE) score 22.1 +/- 2.5) and eight HCs (mean age +/- SD, 75.7 +/- 3.9 y; MMSE score 29.0 +/- 1.2) underwent PET with [F-18]FDDNP and [F-18]FDG.Results: Global [F-18]FDDNP uptake was significantly higher (p < 0.05) in AD patients (1.15 +/- 0.04) than in HCs (1.10 +/- 0.06), while global brain metabolism was lower in AD patients than in HCs (AD patients 0.96 +/- 0.09; HCs 1.13 +/- 0.11; p < 0.05). In HCs, brain glucose metabolism was correlated with age for both the global [F-18]FDG SUVr and in the parietal and posterior cingulate regions, while no correlation was found between age and [F-18]FDDNP uptake. In AD patients, global [F-18]FDDNP uptake and uptake in the frontal and anterior cingulate regions of interest were correlated with MMSE score, while no correlation was observed with brain glucose metabolism.Conclusion: Imaging A beta load and NFT with [F-18]FDDNP can distinguish AD patients from HCs in an advanced elderly population. It seems to be less sensitive than [F-18]FDG to the brain changes observed with normal aging, but more sensitive to cognitive decline in advanced elderly AD patients.