Dual-phase F-florbetaben PET provides cerebral perfusion proxy along with beta-amyloid burden in Alzheimer's disease.

BACKGROUND

This study investigated changes in brain perfusion and Aβ burden according to the progression of Alzheimer's disease (AD) by using a dual-phase F-florbetaben (FBB) PET protocol.

METHODS

Sixty subjects, including 12 with Aβ-negative normal cognition (AβNC), 32 with Aβ-positive mild cognitive impairment (AβMCI), and 16 with Aβ-positive AD (AβAD), were enrolled. A dynamic PET scan was obtained in the early phase (0-10 min, eFBB) and delayed phase (90-110 min, dFBB), which were then averaged into a single frame, respectively. In addition to the averaged eFBB, an R1 parametric map was calculated from the eFBB scan based on a simplified reference tissue model (SRTM). Between-group regional and voxel-wise analyses of the images were performed. The associations between cognitive profiles and PET-derived parameters were investigated.

RESULTS

Both the R1 and eFBB perfusion reductions in the cortical regions were not significantly different between the AβNC and AβMCI groups, while they were significantly reduced from the AβMCI to AβAD groups in regional and voxel-wise analyses. However, cortical Aβ depositions on dFBB were not significantly different between the AβMCI and AβAD groups. There were strong positive correlations between the R1 and eFBB images in regional and voxel-wise analyses. Both perfusion components showed significant correlations with general and specific cognitive profiles.

CONCLUSION

The results of this study demonstrated the feasibility of dual-phase F-FBB PET to evaluate different trajectories of dual biomarkers for neurodegeneration and Aβ burden over the course of AD. In addition, both eFBB and SRTM-based R1 can provide robust indices of brain perfusion.