RESUMO
PURPOSE: This study was undertaken to evaluate whether magnetic resonance (MR) imaging is able to rule out malignancy in the case of BI-RADS 3 microcalcifications, providing a sufficient negative predictive value (NPV) for early work-up, and to reduce unnecessary stereotactically guided vacuum-assisted biopsy (SVAB) procedures. MATERIALS AND METHODS: We prospectively enrolled consecutive women with BI-RADS 3 microcalcifications, who subsequently underwent MR imaging and SVAB. The MR studies were reviewed according to the MR-BI-RADS classification system; lesions assessed as MR-BI-RADS 1 and 2 were considered negative for malignancy, categories MR-BI-RADS 3, 4 and 5 indicated malignant lesions. The presence of additional findings was recorded. Histologic analysis and follow-up were the reference standard. MR sensitivity, specificity, positive predictive value (PPV) and NPV were calculated. RESULTS: The final population consisted of 71 lesions. Histologic analysis showed malignancy in six cases (malignancy rate 8%). At MR analysis, 60 (85%) lesions were considered negative for malignancy and 11 (15%) malignant. Additional MR imaging findings were identified in 19 (27%) patients, all corresponding to nonmalignant lesions. MR sensitivity was 33%, specificity 86%, PPV 18% and NPV 93%. CONCLUSIONS: Because of its relatively low NPV, MR imaging is not able to safely exclude malignancy in the case of BI-RADS 3 microcalcifications. The relatively high malignancy rate found in this study might support SVAB in the case of BI-RADS 3 microcalcifications.
