Targeted Ultrasound of the Breast in Women With Abnormal MRI Findings for Whom Biopsy Has Been Recommended

OBJECTIVE. This study was performed to identify characteristics of suspicious lesions seen on breast MRI that are most likely to have an ultrasound correlate and to determine how often the presumed ultrasound correlate actually corresponds to the MRI finding. MATERIALS AND METHODS. From September 2005 through December 2007, targeted ultrasound was performed for 519 suspicious MRI-detected lesions in 361 women. Retrospective review was performed to determine lesion type (mass vs nonmass), lesion descriptors, lesion size, BI-RADS category, indication for MR examination, patient age, and biopsy outcome. The results of 80 follow-up MRI examinations among 154 cases with concordant benign results on ultrasound-guided biopsy were noted. RESULTS. A presumed ultrasound correlate was found in 290 (56%) of the 519 lesions with masses more likely than nonmass lesions to be seen with ultrasound (62% of masses and 31% of nonmass lesions). Increasing lesion size, assessment of BI-RADS category 5 versus BI-RADS category 4, rim enhancement in masses, and clumped enhancement in nonmass lesions were also significantly more likely to have an ultrasound correlate. On follow-up imaging in 80 benign, concordant ultrasound-guided biopsies, the sonographic lesion did not correspond to the MRI finding in 10. Nine of these 10 lesions underwent subsequent MRI-guided biopsy and five cancers were diagnosed. CONCLUSION. The MR characteristics of lesions most likely to be seen with an ultrasound correlate were mass versus nonmass, increasing size, and increased level of suspicion of the lesion. Clip placement and follow-up imaging after ultrasound-guided biopsy that yields benign concordant results should be performed to detect cases in which the presumed ultrasound correlate is inaccurate to detect unsuspected false-negative biopsies.