Baseline Amyloid PET Centiloid Score and Risk of Amyloid-Related Imaging Abnormalities in Patients Treated With Lecanemab

BACKGROUND AND PURPOSE: Amyloid-related imaging abnormalities (ARIA) are a known complication of anti-amyloid monoclonal antibody therapy for Alzheimer's disease. Centiloid score, derived from amyloid PET/CT, provides a quantitative assessment of baseline amyloid burden; however, its relationship with ARIA risk remains uncertain. This study evaluated whether baseline Centiloid score was associated with ARIA in patients treated with lecanemab and included a secondary exploratory analysis of regional amyloid uptake. MATERIALS AND METHODS: We retrospectively identified patients treated with lecanemab within a single academic health system who underwent pretreatment florbetaben amyloid PET/CT. Centiloid scores were generated using a standardized processing pipeline. Multivariable logistic regression evaluated the association between baseline Centiloid and ARIA, adjusting for age, sex, APOE ε4 carrier status, and baseline cerebral microbleed presence. ARIA-H and ARIA-E subgroups were evaluated separately using Firth penalized logistic regression. A secondary Cox proportional hazards analysis accounted for unequal follow up durations. Exploratory regional analysis compared baseline amyloid uptake in regions that subsequently developed ARIA-E with that in mirrored contralateral regions. RESULTS: = .01). CONCLUSIONS: Baseline global Centiloid was not independently associated with ARIA in patients treated with lecanemab. Exploratory regional analysis demonstrated modest differences in baseline amyloid uptake in regions that subsequently developed ARIA-E, warranting confirmation in larger prospective studies.