Coupled Imaging with [ 18 F]FBB and [ 18 F]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-[18 F]fluoro -D-glucose ([18 F]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-[18 F]fluoroethoxy]ethoxy}ethoxy)phenyl]vinyl}-N-methylaniline (florbetaben; [18 F]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 [18 F]FDG and [18 F]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 [18 F]FDG scans in SPM. Furthermore, 58 control subjects were used as control group for [18 F]FDG PET/CT scans.

RESULTS: SPM analysis in AD patients showed a significant negative correlation between [18 F] FBB and [18 F] 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 [18 F]FBB and [18 FFDG shows that amyloid burden in the brain is related to cortical dysfunction of temporal and parietal lobes in AD.