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

RESULTS

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