Background
[18F]MK-6240 is a novel tau PET tracer developed to minimize off-target binding and improve the image quality. However, studies are riddled by motion due to the long acquisition time and the subjects’ dementia. Limiting motion effect leads to a lower variability in PET quantitation which translates to smaller sample sizes in clinical trials.
We apply a list-mode based motion correction (MC) method to longitudinal studies in 51 subjects and evaluate its effect on estimated standardized uptake value ratio changes (ΔSUVR) in key brain regions. We evaluate the impact of MC on the statistical power of a hypothetical clinical trial.
Individually, 26% of the scans exhibited notable motion, affecting 39% of the longitudinal datasets. MC reduced the standard deviation of ΔSUVR across subjects by -44%, -17%, -13%, and -19% in the entorhinal, inferior temporal, precuneus, and amygdala regions, respectively. In a hypothetical clinical trial, assuming an annualized increase of 10% in the entorhinal region, the sample size needed to detect a 30% reduction in tau accumulation rate after administrating a candidate drug is reduced from 1510 to 398 with MC.
Motion correction helps achieve a smaller sample size required to evaluate the effect of a candidate drug against Alzheimer’s disease.
