A review of current evidence-based clinical applications for breast magnetic resonance imaging.

Magnetic resonance imaging (MRI) is an important new tool for imaging of the breast. MRI has now been demonstrated to be the most sensitive imaging method for detecting breast carcinoma, allowing depiction of cancers that are occult on mammography, ultrasound, and clinical breast examination. This is tempered by imperfect specificity due to overlap in the features of benign and malignant lesions, and by higher examination cost and more limited availability compared to other breast imaging tests. This article describes the current evidence-based clinical indications for use of breast MRI. Specifically, MRI has been shown to be advantageous for cancer assessment for screening patients at high risk, evaluating patients with a new breast cancer diagnosis, monitoring patients undergoing neoadjuvant chemotherapy, and evaluating patients with metastatic axillary adenocarcinoma and unknown primary site. This tool has also been shown to be useful for the evaluation of silicone breast implant integrity. Employment of breast MRI as a problem solving technique for equivocal mammographic or clinical findings is controversial. For each of these clinical applications, the evidence regarding the diagnostic accuracy of breast MRI will be reviewed. An understanding of the current evidence will facilitate the most appropriate utilization of this important medical resource.