Magnetic resonance imaging of the breast in characterizing positive or uncertain mammographic findings.

A total of 38 suspected primary (26) or recurrent (12) breast tumors underwent enhanced magnetic resonance imaging (MRI) of the breast after positive (19) or uncertain (19) mammography. Spin echo T1-weighted images before and after intravenous administration of 0.15 mmol/kg Gd-DTPA, the latter ones at 1, 3, and 5 min, were obtained to characterize the mammographic findings. When contrast enhancement was absent, the same images were also obtained at 10 min. Evident and early focal enhancement was considered as an MRI sign of malignancy. All the lesions were submitted to histological examination (seven by core-biopsy only). Mammography results were 23 true positives and 15 false positives. MRI results were 22 true positives, 13 true negatives, 2 false positives, and 1 false negative. Twelve uncertain-mammography cases became true negatives at MRI; 1 uncertain-mammography case was the only MRI false negative; 1 positive-mammography cases became true negative at MRI. Resting on this limited series of patients, MRI is confirmed as a useful imaging technique after uncertain mammography.