Purpose
The aim of this study was to investigate the longitudinal positron emission tomography (PET) metabolic changes in the elderly.
Procedures
Nineteen nondemented subjects (mean Mini-Mental Status Examination 29.4 ± 0.7 SD) underwent two detailed neuropsychological
evaluations and resting 2-deoxy-2-[F-18]fluoro-d-glucose (FDG)-PET scan (interval 21.7 ± 3.7 months), baseline structural 3T magnetic resonance (MR) imaging, and apolipoprotein
E4 genotyping. Cortical PET metabolic changes were analyzed in 3-D using the cortical pattern matching technique.
Results
Baseline vs. follow-up whole-group comparison revealed significant metabolic decline bilaterally in the posterior temporal,
parietal, and occipital lobes and the left lateral frontal cortex. The declining group demonstrated 10–15% decline in bilateral
posterior cingulate/precuneus, posterior temporal, parietal, and occipital cortices. The cognitively stable group showed 2.5–5%
similarly distributed decline. ApoE4-positive individuals underwent 5–15% metabolic decline in the posterior association cortices.
Conclusions
Using 3-D surface-based MR-guided FDG-PET mapping, significant metabolic changes were seen in five posterior and the left
lateral frontal regions. The changes were more pronounced for the declining relative to the cognitively stable group.
Key words Positron emission tomography (PET) - Alzheimer's disease (AD) - Mild cognitive impairment (MCI) - Cognitive decline
This original article introduces a new powerful technique for analysis of FDG-PET data, representing the first application
of PET surface feature-guided analysis to cognitive aging and dementia.