Quantification of global gray matter amyloid-β plaque from 18F-Florbetaben PET/MRI and correlation to BAPL score in patients with cognitive impairment.

INTRODUCTION: Multiple standardized uptake value ratio (SUVR) and Centiloid (CL) thresholds exist for amyloid‑β (Aβ) positron emission tomography (PET) to classify scans as negative or positive, yet none reliably stratify brain amyloid plaque load (BAPL). This study proposes a global gray matter-based SUVR/CL model to determine amyloid status and quantitatively differentiate BAPL scores. METHODS: Two 18F-Florbetaben (FBB) PET datasets were analyzed to derive SUVRs and CL values from global gray and white matter. SUVR/CL were integrated with visual assessment and BAPL scoring, resulting in CL thresholds to distinguish amyloid status and cognitive stage. The CL thresholds were validated in an independent local cohort. RESULTS: Global gray-to-white matter CL best stratified amyloid status and BAPL scores, yielding CL thresholds of < 21 and > 38 and high diagnostic accuracy. DISCUSSION: The integrated global CL-BAPL model reliably stratified amyloid positivity and BAPL level, suggesting that it could serve as a complementary tool to visual assessment.