P4‐186: Kinetic evaluation of three newly developed radioligands for human tau imaging

voxel-wise. Results: Peak SUV values were approximately 3, 1.5 and 3.5 for [C]RO6924963, [C]RO6931643, and [F] RO6958948, respectively. The retention of [C]RO6931643 and [F]RO6958948 in HS was much lower than that of [C] RO6924963. For [C]RO6931643 and [F]RO6958948 (in AD), highest uptake was seen in the frontal (Fr), temporal (Tp), parietal (Pa), occipital (Oc), and fusiform (Fs) cortices, and the entorhinal area (ER). SUVR60-90 values ranged from 1.22 (L. Fr) to 1.55 (L. Oc) for [C]RO6931643, and 1.39 (R.Fr) to 2.25 (L. Fs) for [F]RO6958948, and VT ranged from 2.28 (R. ER) to 3.14 (L. Tp), and 3.98 (R. ER) to 5.62 (L. Tp), respectively. Regional analysis of SUVR and VT for [ C]RO6931643 and [F]RO6958948 clearly allowed AD and HS to be distinguished. When compared to HS, the two tracers showed robust group effects (F>90; p1⁄4<10; two-way ANOVA) on SUVR and VT, and significant group differences (p<0.05 with Bonferroni correction; without overlap) in 6 of 12 regions for [C]RO6931643 and 4 of 12 for [F]RO6958948 (using SUVR). Voxel-wise analysis of SUVR revealed clusters of significantly higher uptake in AD compared to HS in Fs for [C]RO6931643 (7 AD vs. 5 HS), and [F] RO6958948 (5 AD vs. 5 HS). There were no radiolabelled metabolites nor defluorination of [F]RO6958948. Conclusions: Our data supports further evaluation of [F]RO6958948. Kinetic analysis is reported in detail in Kuwabara, AAIC 2015.