Visual read performance of ¹⁸F-Florbetapir and ¹⁸F-NAV4694 Aβ PET compared against Centiloid reference standard in a paired cohort

INTRODUCTION: Visual assessment remains standard practice to rule out amyloid-β (Aβ) pathology. ¹⁸F-NAV4694 (NAV) has high affinity for Aβ potentially detecting lower levels than other F-18 Aβ tracers. METHODS: One hundred fifty participants in the AIBL study underwent both ¹⁸F-Florbetapir (FBP) and NAV Aβ PET scans. PET scans were assessed by six nuclear medicine physicians against Centiloid (CL) quantification. An optimized reference region was utilized for FBP as it improved CL–visual read correlations. Inter-reader agreement of visual assessment was measured using Fleiss’ Kappa. RESULTS: Mean peak accuracy for visual read exceeded 95% for both NAV and FBP. However, peak accuracy for NAV visual reads was achieved at 14–15CL compared to 38–46CL for FBP. Higher inter-reader agreement was observed for NAV compared to FBP. DISCUSSION: For mild to moderate elevation in Aβ, visual read of NAV is more sensitive and consistent than visual read of FBP by both experienced and novice readers.