Krammer J, et al. - The purpose of this study is to ascertain the accuracy of postoperative MR in predicting residual disease in women with positive margins, emphasizing the size thresholds at which residual disease can be confidently identified. In the light of these outcomes, post-operative breast MR can accurately describe ≥5-mm residual disease at the surgical cavity and unsuspected multifocal/multicentric disease. These outcomes have the potential to lead to the more appropriate selection of second surgical procedures in women with positive margins.