MR imaging assessment of the breast after breast conservation therapy: distinguishing benign from malignant lesions.

Dynamic contrast material-enhanced magnetic resonance (MR) imaging has emerged as a valuable tool in evaluation of women who have undergone lumpectomy and whole-breast radiation therapy for breast cancer. Early diagnosis of local recurrence by means of close clinical and imaging follow-up is an important component of a breast-conserving strategy, as it may improve survival. In the post-breast conservation therapy (BCT) breast, resolving edema, fat necrosis, a small focal area of non-masslike enhancement (NMLE), and thin linear NMLE at the lumpectomy site can all be expected findings. In contrast, masslike enhancement or NMLE of ductal or segmental distribution can indicate recurrence. Therefore, at MR imaging of the post-BCT breast, it is important to identify lesions that are benign or appropriate for short-interval imaging surveillance to minimize unnecessary intervention, as well as to discern suspicious lesions and optimize the diagnosis of recurrence.