title: Real-time magnetic resonance-guided endovascular repair of experimental abdominal aortic aneurysm in swine.
abstract: OBJECTIVE
  This study tested the hypotheses that endografts can be visualized and navigated in vivo solely under real-time magnetic resonance imaging (rtMRI) guidance to repair experimental abdominal aortic aneurysms (AAA) in swine, and that MRI can provide immediate assessment of endograft apposition and aneurysm exclusion.
  
  
  BACKGROUND
  Endovascular repair for AAA is limited by endoleak caused by inflow or outflow malapposition. The ability of rtMRI to image soft tissue and flow may improve on X-ray guidance of this procedure.
  
  
  METHODS
  Infrarenal AAA was created in swine by balloon overstretch. We used one passive commercial endograft, imaged based on metal-induced MRI artifacts, and several types of homemade active endografts, incorporating MRI receiver coils (antennae). Custom interactive rtMRI features included color coding the catheter-antenna signals individually, simultaneous multislice imaging, and real-time three-dimensional rendering.
  
  
  RESULTS
  Eleven repairs were performed solely using rtMRI, simultaneously depicting the device and soft-tissue pathology during endograft deployment. Active devices proved most useful. Intraprocedural MRI provided anatomic confirmation of stent strut apposition and functional corroboration of aneurysm exclusion and restoration of laminar flow in successful cases. In two cases, there was clear evidence of contrast accumulation in the aneurysm sac, denoting endoleak.
  
  
  CONCLUSIONS
  Endovascular AAA repair is feasible under rtMRI guidance. Active endografts facilitate device visualization and complement the soft tissue contrast afforded by MRI for precise positioning and deployment. Magnetic resonance imaging also permits immediate post-procedural anatomic and functional evaluation of successful aneurysm exclusion.
authors.affiliation: Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute/NIH, Building 10, Rm 2C713, Bethesda, MD 20892-1538, USA.
authors.forename: Venkatesh K
authors.initials: VK
authors.lastname: Raman
authors.forename: Parag V
authors.initials: PV
authors.lastname: Karmarkar
authors.forename: Michael A
authors.initials: MA
authors.lastname: Guttman
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Dick
authors.forename: Dana C
authors.initials: DC
authors.lastname: Peters
authors.forename: Cengizhan
authors.initials: C
authors.lastname: Ozturk
authors.forename: Breno S S
authors.initials: BS
authors.lastname: Pessanha
authors.forename: Richard B
authors.initials: RB
authors.lastname: Thompson
authors.forename: Amish N
authors.initials: AN
authors.lastname: Raval
authors.forename: Ranil
authors.initials: R
authors.lastname: DeSilva
authors.forename: Ronnier J
authors.initials: RJ
authors.lastname: Aviles
authors.forename: Ergin
authors.initials: E
authors.lastname: Atalar
authors.forename: Elliot R
authors.initials: ER
authors.lastname: McVeigh
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lederman
mesh_terms: D017130:Angioplasty / Q000379:methods*; D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D004195:Disease Models, Animal; D005240:Feasibility Studies; D008279:Magnetic Resonance Imaging; D011474:Prosthesis Design; D011859:Radiography; D015607:Stents; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013552:Swine