MR-guided stereotactic breast biopsy using a mixed ferromagnetic-nonmagnetic coaxial system with 12-to 18-gauge needles: clinical experience and long-term outcome

This study investigated the clinical application of a magnetic-resonance (MR)-guided breast biopsy (MRBB) system consisting of a nonmagnetic coaxial needle and a ferromagnetic core biopsy needle. MRBB was performed on 70 breast lesions. The biopsy device consisted of a nonmagnetic 14- to 16-gauge coaxial needle and a ferromagnetic 16- to 18-gauge biopsy needle. Of the 70 lesions, 29 were malignant and 41 nonmalignant. All 29 malignant lesions underwent surgery and were confirmed as malignant at final histology. Of the 41 nonmalignant lesions, 35 underwent follow-up breast MR imaging (mean, 26 +/- 19 months), which demonstrated no lesions changes; six lesions underwent surgery because of poor radiological-pathological correlation; of these 6 lesions, 3 were nonmalignant, one was borderline (lobular carcinoma in situ) and two were malignant (well-differentiated tubular carcinoma and infiltrating ductal carcinoma). Sensitivity, specificity, positive and negative predictive values and diagnostic accuracy were, respectively, 93.5%, 100%, 100%, 95.1% and 97.1% if the lobular carcinoma in situ was considered a nonmalignant histological result, and 90.6%, 100%, 100%, 92.7% and 95.7% if the lobular carcinoma in situ was considered malignant. MRBB with a ferromagnetic-nonmagnetic coaxial system represented an easy way to perform a biopsy procedure and was easily applicable in the routine clinical setting.