In a clinical trial, it may be necessary to incorporate multiple centers to get a sufficiently large sample size. Trials that use imaging may suffer from heterogeneity among centers in terms of scanner platform. In the SPRINT-MS trial, diffusion tensor imaging (DTI) measures indicated a larger treatment effect than brain parenchymal fraction (BPF). However, the effect measured by DTI was not statistically significant. In this study, we examine the hypothesis that heterogeneity in scanner type contributed to variance in DTI measures, reducing the statistical power of the measurement.