Clinical usefulness of MR imaging of the breast in the evaluation of the problematic mammogram

OBJECTIVE. This study was undertaken to determine the usefulness of MR imag ing of the breast as an adjunct to mammography in problematic cases in whic h the significance, presence, or location of an abnormality could not be de termined. MATERIALS AND METHODS. From January 1993 through February 1998, 86 lesions for which histologic or mammographic follow-up was available were evaluated by breast MR imaging because of equivocal findings on mammography. MR stud ies were performed with a dedicated breast multicoil on a 1.5-T scanner. Ea rly studies were done using a T1-weighted two-dimensional spin-echo sequenc e before and after the administration of contrast material. Later studies w ere performed using a three-dimensional fast spoiled gradient sequence with fat suppression. Studies were considered to be positive for an abnormality if a focal area of enhancement was seen after contrast administration. RESULTS. MR imaging had positive findings in 38 sites. Twenty-six of these sites corresponded in location to the mammographic abnormality that had pro mpted the recommendation for MR imaging. The remaining 12 sites occurred in areas not suspected mammographically. At biopsy, 10 (26%) of the 38 positi ve sites were malignant. MR imaging had negative findings at 60 other sites that had been suspected mammographically. Of these 60 sites, six were trea ted with excision, all with benign results; the remaining 54 sites showed m ammographic stability on follow-up that ranged from 5 to 66 months (mean, 1 9 months). CONCLUSION MR imaging of the breast can be a valuable adjunct to mammograph y for selected problematic cases.