The application of breast MRI in staging and screening for breast cancer.

Contrast-enhanced breast magnetic resonance imaging (MRI) is a relatively new but increasingly used modality for the detection of breast cancer. MRI has demonstrated utility in identifying additional tumor foci and extent of disease in patients with known breast cancer. This is especially useful with invasive lobular carcinoma, which is difficult to evaluate on mammography. MRI has been found to identify the primary tumor in 70% to 86% of cases of occult breast cancer. Contrast-enhanced breast MRI has shown some usefulness in the detection of residual cancer following surgery but is limited by postoperative changes. In patients who have undergone neoadjuvant chemotherapy, breast MRI is most accurate in those patients in whom there is little or no response to chemotherapy. The use of contrast-enhanced breast MRlfor breast cancer screening is controversial. It has only been used in afew small studies of high-risk patients. The limitations of breast MRI include uptake in benign lesions and normal tissue, sensitivity for ductal carcinoma in situ, cost, and availability. This paper will discuss the uses, benefits, and limitations of contrast-enhanced breast MRI in the staging and screening of breast cancer.