Amyloid PET Quantitation and Centiloid Thresholds in the Diagnosis of Alzheimer Disease: An Individual Participant Data Meta-Analysis.

A Centiloid cutoff of 18 reliably indicates amyloid positivity in PET scans, with a high correlation (Cohen κ=0.86) to visual reads across diverse studies.

• Why it matters: Standardized thresholds are essential for consistent diagnosis and treatment decisions in Alzheimer’s disease, but current methods vary, creating uncertainty.
• What they did: The study pooled individual data from 53 studies involving 49,227 participants, applying Gaussian mixture models and meta-analytic techniques to determine robust positivity cutoffs.
• The result: Findings suggest a primary positivity threshold at 18 Centiloids, with a double-cutoff range (11–26) for cautious interpretation, enabling more precise and standardized clinical assessments.