MR imaging-guided large-core (14-gauge) needle biopsy of small lesions visible at breast MR imaging alone

PURPOSE: To report our experience With magnetic resonance (MR) imaging-guided large-core breast biopsy of lesions visible at breast MR imaging only. MATERIALS AND METHODS: Stereotactic large-core (14-gauge) needle biopsy of 78 lesions visible at MR imaging only was performed with MR imaging guidance in 59 patients. Results were validated with excisional biopsy or mastectomy in 42 lesions and with radiologic-pathologic correlation and/or follow-up MR imaging for at least 2 years in another 17 lesions. The accuracy of MR imaging-guided core biopsy was determined for those 59 lesions with established validation. The effect on patient treatment was evaluated by comparing the prebiopsy treatment plan with the ultimate treatment. RESULTS: Histologic diagnosis from core biopsy was possible in 77 (99%) of 78 lesions. In the 59 lesions with established validation, the diagnostic accuracy of MR imaging-guided core biopsy was 98% (58 of 59). Successful MR imaging-guided core biopsy findings changed treatment in 70% (54 of 77) of lesions. Difficulties were due to the unsatisfactory performance of earlier types of MR imaging-compatible biopsy guns and decreasing target visibility during intervention. CONCLUSION: MR imaging-guided large-core stereotactic breast biopsy is sufficiently accurate for obtaining histologic proof of lesions visible only at MR imaging. It can change patient treatment by reducing unnecessary surgical biopsy and can enable one-step surgery for breast Cancers.