Concordance Between Amyloid-PET Quantification and Real-World Visual Reads

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Amyloid positron emission tomography (PET) is increasingly used for diagnosing cognitive impairment.
• Clinical use is rising due to expanded payer coverage and new antiamyloid therapies.
• Real-world clinical settings present challenges like non-standardized acquisition and comorbidities, potentially affecting accuracy.

Purpose of the Study:

• To compare visual interpretation of amyloid-PET scans in clinical practice with central quantification.
• To assess the accuracy of visual reads in real-world settings.

Main Methods:

• Cross-sectional quality improvement study using data from the Imaging Dementia-Evidence for Amyloid Scanning study.
• Included 10,774 Medicare beneficiaries aged 65+ with cognitive decline across 294 US imaging facilities.
• Compared local visual reads with central quantification using the Centiloid (CL) scale (threshold: 24.4 CL).

Main Results:

• High agreement between visual reads and central quantification (86.3% concordance, Cohen κ=0.72).
• 61% of scans were visually positive, and 59% were quantitatively positive.
• Higher concordance observed in female patients, White race, and with specific radiotracers ([18F]flutemetamol, [18F]florbetaben).

Conclusions:

• High concordance supports the validity of visual interpretation of amyloid-PET scans in clinical practice.
• Visual reads are a reliable method for assessing amyloid status in patients with cognitive decline.
• Findings reinforce the utility of amyloid-PET in guiding diagnosis and treatment decisions.