Effects of apolipoprotein E ε4 on amyloid deposition and relative cerebral perfusion in cognitively normal individuals: a dual-phase 18 F-florbetaben PET study.

OBJECTIVES

Apolipoprotein E (APOE) genotypes, amyloid burden, and relative cerebral perfusion surrogate provide crucial insights into Alzheimer's disease pathophysiology. This study aimed to investigate the effects of APOE ε4 on relative perfusion and amyloid deposition in cognitively normal individuals using dual-phase 18 F-florbetaben PET.

METHODS

Cognitively normal subjects who underwent dual-phase 18 F-FBB PET and APOE genotyping were included. Participants carrying at least one ε4 allele were classified as carriers. Standardized uptake value ratios (SUVRs) were analyzed for relative perfusion and amyloid deposition using early phase 18 F-florbetaben (eFBB) and delayed-phase FBB (dFBB), respectively, in the composite region, including the frontal, parietal, temporal, and occipital cortices, as well as the precuneus, cingulate, and striatum. Target subregions comprised the frontal, parietal, temporal, and occipital cortices along with the precuneus. Correlations between eFBB and dFBB SUVRs were also examined.

RESULTS

APOE ε4 carriers exhibited significantly higher relative perfusion in the composite region ( P  = 0.0042), frontal cortex ( P  = 0.0054), and parietal cortex ( P  = 0.0056). Increased amyloid burden was observed in the composite region ( P  = 0.0065), frontal cortex ( P  = 0.0028) and precuneus ( P  = 0.0071). Moreover, eFBB and dFBB SUVRs were significantly positively correlated in the temporal cortex ( P  = 0.0007) and precuneus ( P  = 0.0080).

CONCLUSION

APOE ε4 may be associated with distinct patterns of increased amyloid deposition and relative perfusion in specific brain regions in cognitively normal individuals. Dual-phase 18 F-FBB PET may provide complementary information on Alzheimer's disease-related changes in APOE ε4 carriers during the preclinical stage.