Breast magnetic resonance imaging: an overview for nonradiologists

Magnetic resonance imaging is a major component of breast imaging. Many studies have shown that magnetic resonance imaging is the most sensitive imaging method for detecting invasive breast cancer in comparison with mammography, ultrasound, and clinical breast examinations. Evidence-based clinical indications for breast magnetic resonance imaging include screening patients at high risk for breast cancer, including those with breast/ovarian cancer genes (BRCA1 and BRCA2), those who are untested first-degree relatives of carriers of these genes, those whose lifetime risk of developing breast cancer is 20% to 25% or greater, those who had chest radiation when they were 10 to 30 years old, and those who have or are first-degree relatives of people with Li-Fraumeni syndrome, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome. Breast magnetic resonance imaging is performed in conjunction with mammography and does not replace mammography. Outside of the screening population, utilization of breast magnetic resonance imaging for newly diagnosed breast cancer patients and its use as a problem-solving technique for equivocal mammographic or clinical findings remain controversial. An understanding of the current evidence facilitates appropriate utilization of this important medical resource. This article discusses indications for ordering breast magnetic resonance imaging and how to read the breast magnetic resonance imaging report and understand the lexicon used.