Amyloid PET Quantitation and Centiloid Thresholds in the Diagnosis of Alzheimer Disease: An Individual Participant Data Meta-Analysis.
JAMAOct 6, 2026
Ganna Blazhenets, David N Soleimani-Meigooni, Konstantinos Chiotis et al.
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In 30 seconds
This individual participant data meta-analysis examined amyloid PET scans from 49,227 participants across 53 studies to establish Centiloid positivity cutoffs for Alzheimer disease diagnosis. The analysis identified a single cutoff of 18 Centiloids for positivity and a double-cutoff approach indicating high confidence for negative scans below 11 Centiloids and positive scans above 26 Centiloids.
Key findings
- A single cutoff for positivity was established at 18 Centiloids (95% CI, 16-19).
- Negative scans were confidently interpreted below 11 Centiloids (95% CI, 9-13).
- Positive scans were confidently interpreted above 26 Centiloids (95% CI, 24-28).
- Centiloids showed high predictive value for visual positivity with a Cohen κ of 0.86 (95% CI, 0.83-0.89).
Why it matters
Establishing standardized Centiloid cutoffs enhances the accuracy of amyloid PET interpretations, which is crucial for diagnosing Alzheimer disease and determining eligibility for amyloid-targeting therapies.