The Yield of Pre-operative Breast MRI in Patients According to Breast Tissue Density.

• Preoperative MRI detects many additional lesions not seen on mammography. • Increased breast density correlates with more findings on preoperative breast MRI (p<0.0001). • Extremely dense breasts are more likely to have additional findings on MRI. • Increased breast density is associated with more MRI findings that changed management.