Women who have had a questionable mammogram, are considered at elevated risk and require a second screening tool, or have had a positive biopsy and need assessment of the extent of cancer, can benefit from breast magnetic resonance imaging, or breast MRI.

Roughly 1 in 10 women who have a mammogram require further testing to gain more detailed information. Mammography is the first choice for routine screening because it is highly sensitive to the presence of micro calcifications, which can be an early sign of cancer.