Advantages of magnetic resonance imaging in breast surgery treatment planning.

Preoperative magnetic resonance imaging (MRI) was performed in 40 patients with malignant and benign breast tumors. Images were qualitatively evaluated to determine features of MRI that would benefit breast surgery treatment planning. MRI was found to be exceptional in demonstrating the relationship of tumors with respect to structures such as the chest wall, nipple, and skin. Tumor size was estimated by MRI, mammography, and gross pathological measurement in the 32 patients confirmed to have a malignant tumor of the breast. MRI estimated the tumor size to be larger than mammography in 71% of the cases and larger than pathological measurement in 84% of the cases. Compared with the standard method for determining tumor size (pathological measurement), MRI would have upstaged 22% of the evaluated cases from T1 to T2 and 10% of the cases from T2 to T3. MRI may prove useful in selecting patients for breast conserving therapy.