MR imaging: breast cancer staging and screening.

This review describes the current knowledge and challenges of breast cancer staging and screening with MRI of the breast. Assessment of local disease extent, including tumor size, multicentricity, and chest wall invasion, can be obtained more accurately with MRI than with mammography. Moreover, international experts have established standardized reporting of MRI staging results, taking into account tumor size measurements and the number of breast quadrants involved. Results from MRI assessment of the axilla and skin are promising, but need further refinement. Preliminary results of the use of breast MRI in patients at high risk for breast cancer demonstrated a superiority of breast MRI over the combined use of mammography and high-frequency ultrasound. The role of MRI in this subset of patients may be confirmed by ongoing larger multicenter trials. Strict protocol conditions are mandatory to maintain a high standard of quality. Confirming the nature of "MRI-only" lesions with MRI-guided biopsy systems will allow changes in treatment planning. More accurate tumor diagnosis and tumor volume evaluation may allow minimally invasive treatment strategies.