Interventional MR-guided excisional biopsy of breast lesions

Interventional MR (IMR) machines have produced unique opportunities for ima ge-guided surgery. The open configuration design and fast pulse sequences a llow intraoperative scanning to monitor procedures. This study was undertak en to assess the potential use of IMR for image-guided surgery. Benign brea st lesion excision was chosen as an uncomplicated surgical model. Ten femal e patients with known benign tumors underwent excision biopsy under general anesthesia in a Signs SP10 .5-T IMR machine (General Electric Medical Syst ems, Milwaukee, WI), Lesions were localized with precontrast and postcontra st (intravenous gadolinium-diethylenetriamine pentaacetic acid,.2 mmol/kg) fast multiplanar spoiled gradient-recalled acquisition in the steady state (GRASS) sequences. Preoperative "real-time" fast gradient-recalled sequence s were also obtained using the Flashpoint (General Electric Medical Systems , Milwaukee, WI) tracker device. The maximum dimensions of each lesion were measured from the resulting images. Excision was performed using titanium instruments and an ultrasonically activated scalpel. Intraoperative real-ti me scanning demonstrated the resection margin and confirmed complete excisi on. The maximum dimensions of the macroscopic specimens were compared with those from the MR images. All tumors were visualized with the Signa scanner and real-time imaging and the images were enhanced after intravenous contr ast. Maximum dimensions on histologic examination were not significantly di fferent from those measured from Signs (P > .17) or real-time images (p > . 4). There was no significant difference between lesion size from Signs and real-time images (P > .25). All postprocedure scans demonstrated complete e xcision. There were six fibroadenomas, two foci of sclerosing adenosis, one area of fibrocystic disease, and one schwannoma, Intraoperative MR scannin g reliably identifies palpable breast tumors and can accurately guide surgi cal excision. Further work using MR guidance can now be performed in other general surgical areas.