title: Evaluation of MR/fluoroscopy-guided portosystemic shunt creation in a swine model.
abstract: OBJECTIVE
  To evaluate three different percutaneous portosystemic shunts created with magnetic resonance (MR) imaging and fluoroscopy guidance in a swine model.
  
  
  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, 40-45 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins Medical Institutions, Blalock 545, 600 North Wolfe Street, Baltimore, MD 21287, USA. aarepal@jhmi.edu
authors.forename: Aravind
authors.initials: A
authors.lastname: Arepally
authors.forename: Parag V
authors.initials: PV
authors.lastname: Karmarkar
authors.forename: Di
authors.initials: D
authors.lastname: Qian
authors.forename: Brad
authors.initials: B
authors.lastname: Barnett
authors.forename: Ergin
authors.initials: E
authors.lastname: Atalar
mesh_terms: D000497:Alloys; D000818:Animals; D004867:Equipment Design; D005471:Fluoroscopy; D018810:Magnetic Resonance Angiography; D008642:Mesenteric Veins; D011169:Portal Vein; D011170:Portasystemic Shunt, Surgical; D011677:Punctures; D015641:Radiography, Interventional; D013552:Swine; D014654:Vascular Patency; D014682:Vena Cava, Inferior
chemical_list: D000497:Alloys; C013616:nitinol