Summary: Evaluation of MR/Fluoroscopyguided
Portosystemic Shunt Creation in a Swine Model
Aravind Arepally, MD, Parag V. Karmarkar, MS, Di Qian, MS, Brad Barnett, BS, and Ergin Atalar, PhD
PURPOSE: To evaluate three different percutaneous portosystemic shunts created with magnetic resonance (MR)
imaging and fluoroscopy guidance in a swine model.
MATERIALS AND METHODS: In stage 1 of the experiment, an active MR intravascular needle system was created
for needle tracking and extracaval punctures. Twenty inferior vena cava (IVC)/superior mesenteric vein (SMV)/portal
vein (PV) punctures were performed in 10 swine (weight, 4045 kg) in a 1.5-T short-bore interventional MR imager.
With use of a real-time MR imaging sequence, the needle was guided through the IVC and into the SMV or PV (N
20 punctures). After confirmation, a wire was advanced into the portal venous system under MR imaging guidance
(N 20). In stage 2, animals were transferred to the radiographic fluoroscopy suite for deployment of shunts. Three
different shunts were evaluated in this study: (i) a commercial stent-graft, (ii) a prototype bridging stent, and (iii) a
prototype nitinol vascular anastomotic device. Postprocedural necropsy was performed in all animals.
RESULTS: Successful MR-guided IVC/SMV punctures were performed in all 20 procedures (100%). All three shunts
were deployed. Stent-grafts had the poorest mechanism for securing a shunt. The vascular anastomotic device and the
bridging stent had more secure anchoring mechanisms but also had higher technical failure rates (50% and 40%,
respectively). When deployed successfully, the vascular anastomotic device resulted in no bleeding at the sites of
punctures at necropsy.
CONCLUSION: Percutaneous shunts and vascular anastomoses between the portal mesenteric venous system and
IVC were successfully created with use of a combination of MR imaging and conventional fluoroscopy for guidance.