Breast MRI has paved the way for new thinking regarding the workup of women recently diagnosed with breast cancer and the screening of high-risk women. The routine use of MRI preoperatively is advocated, particularly in young patients and women with dense breasts where mammography is significantly less sensitive for the detection of malignancy. Additionally, MRI is particularly helpful in those women who have core biopsy results showing extensive intraductal component (>25%) or invasive lobular carcinoma, and in those women with increased risk of positive margins. However, as with any imaging modality, breast magnetic resonance has limitations. Because breast magnetic resonance has lower specificity than some modalities, clinicians must be selective in identifying those women most likely to benefit from this additional imaging. Many recent publications show that MRI does not unduly raise the false-positive biopsy rate while providing specificity similar to that of mammography and higher than that of ultrasound. Positive margin rates for breast conservation therapy range from 30% to 50% and the achievement of negative margins is directly related to low recurrence rates. Magnetic resonance provides improved preoperative staging, which in turn may reduce recurrence rates and improve patient outcome. Breast MRI should be used in concert with other modalities, such as mammography and ultrasound, for the highest sensitivity for detecting malignancy. Long-term studies are needed to validate the impact of screening and diagnostic breast MRI on patient outcomes.
ASJC Scopus subject areas