MR imaging-guided 9-gauge vacuum-assisted core-needle breast biopsy: initial experience.

PURPOSE: To perform magnetic resonance (MR) imaging-compatible vacuum-assisted 9-gauge core-needle biopsy of suspicious enhancing breast lesions identified at MR imaging.

MATERIALS AND METHODS: The institutional review board granted exempt status for this HIPAA-compliant study and waived the requirement for informed consent. The MR imaging-guided 9-gauge vacuum-assisted core-needle biopsy findings of 85 lesions in 75 patients aged 31-89 years were retrospectively reviewed. The biopsies were performed as part of the patients' clinical care with a Food and Drug Administration-approved biopsy system and not within a research protocol. All included patients had received a diagnosis of malignant, benign, or high-risk (for cancer) breast tissue at core-needle biopsy and had undergone subsequent surgery or follow-up imaging. MR imaging-guided biopsy results were compared with final histopathologic or follow-up imaging findings.

RESULTS: At MR imaging-guided core-needle biopsy, malignancy was identified in 52 (61%) lesions: 35 invasive cancers and 17 ductal carcinoma in situ (DCIS) lesions. Four (24%) of the 17 DCIS lesions were upgraded to invasive cancer at excisional biopsy or mastectomy. A high-risk lesion (ie, atypical ductal hyperplasia, atypical lobular hyperplasia, lobular carcinoma in situ, or radial scar) was identified in 18 (21%) cases. Two (25%) of eight atypical ductal hyperplasia lesions were upgraded to DCIS at excision. No malignancy was found in the atypical lobular hyperplasia (n = 2), lobular carcinoma in situ (n = 5), or radial scar (n = 3) lesions. Fifteen (18%) lesions were found to be benign lesions of unknown type at excision or mastectomy. For 13 of these 15 lesions, the benign results were concordant with the imaging findings. Both (two of 86, 2%) discordant cases represented false-negative lesions. The remaining 13 benign lesions were validated at excisional biopsy (n = 9) or follow-up imaging (n = 4).

CONCLUSION: Initial experience revealed MR imaging-guided 9-gauge vacuum-assisted core-needle breast biopsy to be a reasonable alternative to MR imaging-guided wire localization of suspicious lesions identified at MR imaging only, on the basis of published information regarding the latter.