Prediction of Amyloid Positivity in Lewy Body Disease Using Early-Phase 18F-FP-CIT PET Images

Purpose: To explore whether alterations in regional cerebral perfusion observed on early-phase 18 F-FP-CIT PET imaging could predict β-amyloid positivity in patients with Lewy body disease (LBD). Methods: We enrolled 132 patients with LBD (78 dementia with Lewy bodies and 54 Parkinson disease) who underwent dual-phase 18 F-FP-CIT PET and 18 F-FBB PET scans at initial assessment. Patients were divided into the amyloid-positive (n=69) and amyloid-negative (n=63) groups. We compared regional uptake on early-phase 18 F-FP-CIT PET images between the 2 groups, whereas a linear discriminant analysis (LDA) was performed to predict β-amyloid positivity based on the standard uptake value ratios (SUVRs) of each region of interest. Mediation analyses were performed to evaluate whether regional cerebral perfusion mediated the association between β-amyloid load and longitudinal changes in the Mini-Mental State Examination (MMSE) scores. Results: There were no significant differences in age, sex, educational attainment, MMSE scores, motor deficits, or striatal dopamine depletion between the amyloid-positive and amyloid-negative groups. The amyloid-positive group exhibited decreased uptake in the parietal, precuneus, middle/inferior temporal, and isthmus cingulate cortices, as well as increased uptake in the caudate, compared with the amyloid-negative group on early-phase 18 F-FP-CIT PET images. LDA prediction model demonstrated that SUVRs of the inferior parietal cortex and caudate optimally distinguished the 2 groups. Greater β-amyloid burden was associated with a more rapid decline in MMSE scores, which was partially mediated by inferior parietal hypoperfusion. Conclusions: Alterations in regional cerebral perfusion on early-phase 18 F-FP-CIT PET imaging may serve as a useful biomarker for predicting β-amyloid deposition in LBD.