Figure 3.

Four-quadrant plot illustrating the relationship between the plasma Aβ42/40 ratio and (A) [¹⁸F]-florbetaben SUVR values and (B) [¹⁸F]-florbetapir SUVR values in the ADRC cohort. Horizontal dashed line = optimal plasma Aβ42/40 ratio cutoff (0.160). Vertical dashed lines = optimized SUVR cutoff values for each tracer. Color coding for amyloid positivity and negativity is based SUVR cutoffs or gold-standard visuals reads. Aβ, beta-amyloid; ADRC, Alzheimer’s Disease Research Center; PET, positron emission tomography; SUVR, standardized uptake value ratio.