Experience with a Multi-Function Stereotactic MRI-guided Breast Imaging Apparatus

Evaluate the accuracy and effectiveness of MRI-guided procedures developed at our institution for wire localization, vacuum-assisted biopsy and US probe delivery (MRI/US image co-registration) for breast lesions. Procedures were facilitated using a common software platform and dedicated breast intervention stretcher developed at our institution. Stereotactic technique required imaging fixed position MR markers and dynamic contrast enhanced scans to locate breast lesions. Fiducial and lesion information were entered into custom software to calculate optimal approach. Verification scans were performed through 2 planes to validate needle position and detect tissue shift. A similar approach was used for US probe positioning. The System was used for 66 procedures ; 38 wire localizations, 6 core biopsies, 2 vacuum-assisted biopsies, and 20 MR/US co-registration procedures. Ail needle positions were verified within the bounds of the lesion on first attempt with depth modification (due to tissue shift) required 14/38 times. Mean positioning error in depth direction was 4,8mm. Average procedure time (with setup) was 62 minutes. Average imaging time from first to scan to verification was 33 minutes. The average time from lesion visualization to wire verification was 9 minutes. The use of MRI intervention guidance software to facilitate needle and US probe positioning has demonstrated to be fast and effective and may lead to improved patient care.