title: MR-guided angioplasty of renal artery stenosis in a pig model: a feasibility study.
abstract: OBJECTIVE
  To test the hypothesis that magnetic resonance (MR) imaging can guide the percutaneous treatment of renal artery stenosis in a pig model.
  
  
  METHODS
  Ameroid constrictors were surgically placed around six renal arteries in four pigs. After 30-36 days, all stenoses were documented by conventional x-ray aortograms. MR-guided renal angioplasty was attempted for three stenoses. For these pigs, MR angiography was performed with use of contrast-enhanced three-dimensional (3D) techniques. The authors visualized catheters by filling them with dilute 4% gadolinium and imaging with two-dimensional (2D) and 3D MR fast spoiled gradient recalled echo techniques. Under MR guidance, the authors advanced a selective catheter into the affected renal artery and crossed the stenosis with a nitinol guide wire. Angioplasty was performed with a balloon catheter filled with dilute gadolinium. Stenosis and luminal diameter measurements were compared before and after angioplasty.
  
  
  RESULTS
  After ameroid constrictor placement, four significant stenoses, one mild stenosis, and one occlusion developed. Under MR guidance, the authors achieved technical success in performing three of three (100%) attempted dilations. After MR-guided angioplasty, the mean reduction in stenosis was 35% and the mean increase in luminal diameter was 1.6 mm.
  
  
  CONCLUSIONS
  Use of MR guidance for the angioplasty of renal artery stenosis in pigs is feasible.
authors.affiliation: Department of Radiology, Medical Physics, and Pathology, University of Wisconsin-Madison Medical School, USA. raomary@facstaff.wisc.edu
authors.forename: R A
authors.initials: RA
authors.lastname: Omary
authors.forename: R
authors.initials: R
authors.lastname: Frayne
authors.forename: O
authors.initials: O
authors.lastname: Unal
authors.forename: T
authors.initials: T
authors.lastname: Warner
authors.forename: F R
authors.initials: FR
authors.lastname: Korosec
authors.forename: C A
authors.initials: CA
authors.lastname: Mistretta
authors.forename: C M
authors.initials: CM
authors.lastname: Strother
authors.forename: T M
authors.initials: TM
authors.lastname: Grist
mesh_terms: D000800:Angioplasty, Balloon / Q000379:methods*; D000818:Animals; D004195:Disease Models, Animal; D005240:Feasibility Studies; D018810:Magnetic Resonance Angiography; D012077:Renal Artery / Q000473:pathology*; D012078:Renal Artery Obstruction / Q000175:diagnosis / Q000628:therapy*; D013552:Swine