Evaluating Reliability of Performance Metrics for Bias Field Correction in MR Brain Images

Introduction. Performance of nonuniformity correction approaches is usually evaluated indirectly, on the basis of remaining tissue intensity variability rather than the actual estimated bias field. Common indirect measures include coefficient of variation of white matter CV(WM) and gray matter CV(GM), and coefficient of joint variation CJV between WM and GM [1]. However, disagreements between indirect measures on what is the best performing method, reported in several recent studies [2,3], suggest that indirect measures might not reliably reflect the true nonuniformity correction performance. Here we examined reliability of several common performance measures using simulated brain data.