Coupled Imaging with [18F]FBB and [18F]FDG in AD Subjects Show a Selective Association Between Amyloid Burden and Cortical Dysfunction in the Brain

Purpose: The present study was aimed to investigate the relationships between dysfunction of cortical glucose metabolism as detectable by means of 2-deoxy-2-[18F]fluoro -D-glucose ([18F]FDG) positron emission tomography/x-ray computed tomography (PET/CT) and amyloid burden as detectable by means of 4-{(E)-2-[4-(2-{2-[2-[18F]fluoroethoxy]ethoxy}ethoxy)phenyl]vinyl}-N-methylaniline (florbetaben; [18F]FBB) in a group of patients affected by Alzheimer’s disease (AD). Procedures: We examined 38 patients newly diagnosed with AD according to the NINCDS-ADRDA criteria. All the subjects underwent a PET/CT scan using both [18F]FDG and [18F]FBB with an average interval of 1 month. We used statistical parametric mapping (SPM8) implemented in Matlab R2012b and WFU pickatlas for the definition of a region of interest (ROI) mask including the whole cortex. These data were then normalized on the counts of the cerebellum and then used for a regression analysis on [18F]FDG scans in SPM. Furthermore, 58 control subjects were used as control group for [18F]FDG PET/CT scans. Results: SPM analysis in AD patients showed a significant negative correlation between [18F] FBB and [18F] FDG uptake in temporal and parietal lobes bilaterally. Of note, these areas in AD patients displayed a marked glucose hypometabolism compared to control group. Conclusions: Combined imaging with [18F]FBB and [18FFDG shows that amyloid burden in the brain is related to cortical dysfunction of temporal and parietal lobes in AD.