Laparoscopic surgery in a 0.5-t interventional magnetic resonance unit

Background: Intraoperative imaging using magnetic resonance imaging (MRI) i s now possible in interventional MR (IMR) units. Magnetic resonance imaging has potential advantages over other methods used to guide surgery. These a dvantages include visualization of structures deep to the two-dimensional e ndoscopic image and clarification of surgical anatomy. This study investiga tes the feasibility of laparoscopic surgery with intraoperative imaging wit hin an IMR unit. Methods: The procedures were performed in a 0.5-T General Electric IMR scan ner. Surgical ergonomics and intraoperative imaging were investigated by pe rforming 10 laparoscopic cholecystectomies on porcine livers in a simulator using magnet-safe laparoscopic instruments and an ultrasonic scalpel for d issection. Intraoperative MR cholangiography (MRC) was performed using T2-w eighted fast-spin-echo (FSE) and single-shot fast-spin-echo (ssFSE) techniq ues with maximal intensity projection (MIP) reconstruction. Two laparoscopi c cholecystectomies then were performed on human patients with intraoperati ve MRC using similar techniques. Results: The simulated procedures allowed the development of surgical techn iques appropriate to this environment. Both FSE and ssFSE produced reasonab le quality intraoperative images, Both patient procedures were performed wi thout complication, The FSE imaging was of poor quality. However, ssFSE pro duced intraoperative images of the gallbladder with partial visualization o f the extrahepatic biliary tree. Conclusions: Laparoscopic surgery in an IMR unit is technically possible. C urrently, intraoperative MRC is difficult, and FSE imaging is very subject to movement artifact. However, the faster ssFSE, with further development, may be a useful technique for intraoperative imaging of the biliary tree du ring MR-guided surgery.