The negative predictive value of breast Magnetic Resonance Imaging in noncalcified BIRADS 3 lesions.

PURPOSE The purpose of this study is to determine whether breast MRI can provide a sufficient NPV to safely rule out malignancy in mammographic BIRADS 3 lesions. MATERIALS AND METHODS In a 3-year consecutive mammographic examination study 176 out of 4391 patients had a lesion classified as BIRADS 3. 76 out of 176 patients underwent breast MRI as diagnostic work-up. Lesions which MRI classified as BIRADS 1 or 2 were considered negative for malignancy. Sensitivity, specificity, PPV and NPV were calculated. RESULTS In 27 out of 76 (35.5%) patients MRI showed no enhancement and was classified as BIRADS 1. In 25 (32.9%) patients MRI showed focal or mass enhancement classified as BIRADS 2. In these 52 (68.4%) patients no malignancy was found during at least 2 years study follow-up. The other 24 (31.6%) patients had a lesion classified as BIRADS ≥ 3. Thirteen of these 24 lesions were malignant by pathology. MRI had a sensitivity of 100% (95% CI: 75-100%), specificity of 82.5% (95% CI: 71-91%), PPV of 54.2% (95% CI: 33-74%) and NPV of 100% (95% CI: 93-100%). CONCLUSION Breast MRI should be used in a diagnostic strategy for the work-up of noncalcified BIRADS 3 lesions. Malignancy is ruled out with a very high level of confidence in the majority of patients (68%), herewith avoiding invasive diagnostic procedures.