[MRI-assisted biopsy and localization of the breast]

If suspicious lesions found with MR imaging cannot be visualized by either mammography or ultrasound, MR imaging--based guidance systems are needed to guide needle biopsy or to allow localization of the lesion before surgery. The authors give an overview of the advantages and disadvantages of biopsy devices presented by different working groups. Furthermore, MR-compatible needle equipment for interventions of the breast is demonstrated. The angulation of the needle and the type of sequence are the most important factors for signal loss due to susceptibility. The strategy in special problem cases (multicentricity, bilateral lesions) is discussed. Control MR imaging within the first week after open biopsy is the best way to document the complete excision of a suspicious hypervascularized lesion after MR-guided wire localization. At our institute, percutaneous biopsy (36 interventions) revealed benign findings in 67% and malignant lesions in 25% of cases. Three biopsies were insufficient. Histology after MR-guided wire localization (136 interventions) showed benign findings in 51% and malignancy in 49% of cases. The suspicious lesion was missed by the surgeon in three cases. We perform MR-guided interventions of the breast routinely in indicated cases.