Feasibility study of a PET-only amyloid quantification method: a comparison with visual interpretation

Objective: Visual evaluation is the standard for amyloid positron emission tomography (PET) examination, though the result depends upon the physician’s subjective review of the images. Therefore, it is expected that objective quantitative evaluation is useful for image interpretation. In this study, we examined the usefulness of the quantitative evaluation of amyloid PET using a PET-only quantification method in comparison with visual evaluation. Methods: In this study we retrospectively investigated a total of 166 individuals, including 58 cognitively normal controls, 62 individuals with mild cognitive impairment, and 46 individuals with early Alzheimer’s disease. They underwent ¹¹C-Pittsburgh compound-B (PiB) PET examination through the Japanese Alzheimer’s Disease Neuroimaging Initiative (J-ADNI). Amyloid accumulation in cerebral cortices was assessed using visual and quantitative methods. The quantitative evaluation was performed using the adaptive template method and empirically PiB-prone region of interest, and the standardized uptake value ratio (SUVR) in each area was obtained. Results: Visual evaluation and SUVR were significantly correlated in the cerebral cortices (ρ = 0.85–0.87; p < 0.05). In visual evaluation, sensitivity, specificity, and accuracy were 78%, 76%, and 77%, respectively. Meanwhile, for quantitative evaluation, sensitivity, specificity, and accuracy were 77%, 79%, and 78% in mean cortical SUVR (mcSUVR) and 79%, 79%, and 79% in maximum SUVR (maxSUVR), respectively. Conclusion: The PET-only quantification method provided a concordant result with visual evaluation and was considered useful for amyloid PET.