Feasibility study of amyloid PET-only quantification; a comparison with visual interpretation.

Abstract 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, objective quantitative evaluation is expected to be 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 A total of 166 individuals, including 58 cognitively normal controls, 62 individuals with mild cognitive impairment, and 46 individuals with early Alzheimer’s disease, were retrospectively investigated. 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, the sensitivity, specificity, and accuracy were 78%, 76%, and 77%, respectively. Meanwhile, for quantitative evaluation, the sensitivity, specificity, and accuracy were 78%, 76%, and 77%, in mean cortical SUVR (mcSUVR) and 79%, 79%, and 79% in maximum SUVR (maxSUVR), respectively. Conclusion The PET-only quantification method resulted in a concordant result with visual evaluation and was considered to be useful for amyloid PET.