MR-GUIDED CHOLECYSTOSTOMY - ASSESSMENT OF BIPLANAR, REAL-TIME NEEDLE TRACKING IN 3 PIGS

Purpose: To demonstrate the feasibility of magnetic resonance (MR)-gui ded cholecystostomy using active, real-time, biplanar MR tracking in a nimal experiments. Methods: Experiments were performed on three fully anesthetized pigs in an interventional MR system (GE open). The gallbl adder was displayed in two orthogonal planes using a heavily T2-weight ed fast spin-echo sequence. These ''cholangio roadmaps'' were displaye d on LCD monitors positioned in front of the interventionalist. A spec ial coaxial MR-tracking needle, equipped with a small receive-only coi l at its tip, was inserted percutaneously into the gallbladder under c ontinuous, biplanar MR guidance. The MR-tracking sequence allowed samp ling of the coil (needle tip) position every 120 msec. The position of the coil was projected onto the two orthogonal ''cholangio roadmap'' images. Results: Successful insertion of the needle was confirmed by a spiration of bile from the gallbladder. The process of aspiration and subsequent instillation of Gd-DTPA into the gallbladder was documented with fast gradient-recalled echo imaging. Conclusion: Biplanar, activ e, real-time MR tracking in combination with ''cholangio roadmaps'' al lows for cholecystostomies in an interventional MRI environment.