Correlation of VTs of 11C-tariquidar (A, n = 5) and 11C-elacridar (B, n = 4, subject 10 not included) (using 2T4K model and plasma input function uncorrected for radiolabeled metabolites) with VTs of (R)-11 C-verapamil in hippocampus, cerebellum, caudate nucleus, putamen, thalamus and gyrus precentralis. Solid lines represent linear regression fits (r = Pearson correlation coefficient).