MR imaging-guided localization and biopsy of breast lesions: initial experience.

PURPOSE: To evaluate the usefulness of a magnetic resonance (MR) imaging-guided system for localization and biopsy of mammographically and clinically occult breast lesions.

MATERIALS AND METHODS: The 11 needle localizations and one cyst aspiration were performed with MR imaging guidance in 11 patients with breast lesions. Two MR systems were tested; both required the patient to lie prone with the breast compressed between medial and lateral plates. One system used a grid with 18-gauge holes placed at 5-mm intervals and two reference markers to position the needle; the other, a stereotaxic external needle guide and a software system to calculate coordinates.

RESULTS: Fibroadenoma, ductal carcinoma in situ, invasive ductal carcinoma, atypical ductal hyperplasia, fat necrosis, and sclerosing adenosis were found at histologic examination. In two cases, biopsies revealed multi-focal breast cancer where mammographic and clinical findings had indicated a single lesion.

CONCLUSION: MR imaging-guided needle localizations may be performed in a clinical setting with the systems described. Accurate localization of mammographically and clinically occult lesions will allow MR imaging to achieve a clinically significant role.