Magnetic resonance imaging-guided biopsy of mammographically and clinically occult breast lesions

Background: Breast magnetic resonance imaging (MRI) is a very sensitive technique for detection of breast cancer. We report on MRI-guided needle localization for biopsy of abnormalities seen only on MRI. Methods: A retrospective review was performed of 231 patients with invasive breast cancer or ductal carcinoma-in-situ who had MRI as part of their evaluation and treatment at the University of Pennsylvania between 1992 and 1998. Clinical, radiological, and pathologic data were examined. Results: MRI needle localization was performed in 41 (18%) patients. MRI needle localization was required for a finding of a mammographically or clinically occult lesion in 31 patients, better MRI definition of tumor in 5 patients, and surgeon's choice in 5 patients. In all cases, MRI localization and excisional biopsy were successfully completed. Nineteen of 31 patients were found to have additional mammographically and clinically occult tumors. There were 12 (29%) false-positive MRI scans. Conclusions: MRI has a high sensitivity for detection of breast cancer; additional mammographically and clinically occult sites of tumor are detected in approximately 1 (15%) of 7 breast cancer patients. These otherwise occult sites of disease can be appropriately biopsied with MRI needle-localization techniques.