Correlations across regional inflammation, cortical thickness, amyloid-β and tau. (A) Scatter plots showing the pairwise relationships between inflammation, amyloid-β (Aβ) and tau PETs (top), as well as each PET tracer’s relationships with volume (bottom) across all three TSPO affinity groups. Data are standardized so that regression slopes equal correlation coefficients. Inflammation and tau exhibit the strongest of all pairwise correlations within each affinity. (B) Box plots display Pearson correlation values for each pairwise PET correlation as well as each PET tracer’s correlation with volume on an individual subject basis. P-values for comparisons are family-wise error (FWE)-corrected. (C) The matrix indicates the average, denoted as r_avg, of all single Pearson intra-individual correlation values in Mild Cognitive Impairment caused by early-onset Alzheimer’s disease (MCI-EOAD) subjects. Among individual FWE-corrected correlations, inflammation and tau were significant in 16/21 subjects, Aβ and tau in 15/21, inflammation and Aβ in 11/22, tau and volume in 13/21, inflammation and volume in 7/25 and Aβ and volume in 2/22. ER176 = ¹¹C-ER176 inflammation PET; SUVR = standardized uptake value ratio.