The role of second-look ultrasound of BIRADS-3 mammary lesions detected by breast MR imaging.

OBJECTIVE To asses the value of second-look ultrasound (US) for identifying BIRADS 3 (Breast Imaging Reporting Data System) mammary lesions detected by breast Magnetic Resonance imaging (MRI). MATERIALS AND METHODS From April 2008 to May 2009 330 breast MRI were performed of which 60 patients are classified as BIRADS 3. 84 lesions underwent second-look US and percutaneous vacuum biopsy Vacora system US-guided. STATISTICAL ANALYSIS lesions were stratified into two groups: visible on US (Group 1) and not visible on US (Group 2). The clinical impact of second-look US was studied in terms of negative predictive value (NPV). RESULTS The positive predictive value (PPV) of category 3 BIRADS MRI was found to be 89%. Second look-US results detected lesions in 51% of the MRI enhancing lesions. The second look-US showed a NPV of 97%. The NPV of second look-US was significantly greater than the NPV of MRI BIRADS 3 (97% vs 89%, p<0.05). The logistic regression analysis showed a higher number of malignant lesions in group 1 than in group 2 (7vs 2, OR 3.7, p<0.05). CONCLUSIONS The second-look US permitted the correct management of subcentimetric MRI BIRADS 3 lesions not visible with conventional imaging tecniques.