title: Comparison of intraarterial MR angiography at 3.0 T with X-ray digital subtraction angiography for detection of renal artery stenosis in swine.
abstract: OBJECTIVE
  To compare the accuracy of catheter-directed intraarterial (IA) magnetic resonance (MR) angiography at 3.0 T with that of x-ray digital subtraction angiography (DSA) for the measurement of renal artery stenosis (RAS) in swine.
  
  
  METHODS
  Unilateral hemodynamically significant RAS (>50%) was induced surgically in six pigs with use of reverse cable ties. One to two weeks after surgery, each pig underwent x-ray DSA and MR angiography before and after percutaneous transluminal balloon angioplasty (PTA). X-ray DSA was performed before and after PTA of RAS by injection of iodinated contrast agent through a 5-F multiple-side hole angiographic catheter placed in the abdominal aorta under fluoroscopic guidance. MR angiography of RAS was performed before and after PTA of RAS on a 3.0-T clinical MR imager with use of gadolinium-based contrast agent. MR angiography and DSA images were analyzed with the full width at half maximum method. Percent stenosis measurements between x-ray DSA and MR angiography were compared with a paired t test and were correlated with linear regression and Bland Altman analysis (alpha = 0.05).
  
  
  RESULTS
  Six cases of RAS were induced and imaged successfully with DSA and MR angiography techniques before and after PTA. On x-ray DSA, median stenoses was 64% (95% CI 57%-80%) before PTA and 20% (95% CI 5%-32%) after PTA. Corresponding MR angiography median stenosis measurement was 69% (95% CI 58%-80%) before PTA and 26% (95% CI 16%-36%) after PTA. A paired t test comparison did not show a difference between DSA and MR angiography (P = .16). RAS measurements on MR angiography correlated closely (P < .01) with DSA measurements (r(2) = 0.92).
  
  
  CONCLUSIONS
  In swine, the accuracy of catheter-directed IA MR angiography with use of a clinical 3.0-T MR imaging unit for the measurement of RAS was similar to that of conventional x-ray DSA.
authors.affiliation: Department of Radiology, Northwestern University, 448 East Ontario Street, Suite 700, Chicago, IL 60611, USA.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Rhee
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Park
authors.forename: Ty A
authors.initials: TA
authors.lastname: Cashen
authors.forename: Wanyong
authors.initials: W
authors.lastname: Shin
authors.forename: Brian E
authors.initials: BE
authors.lastname: Schirf
authors.forename: James A
authors.initials: JA
authors.lastname: Gehl
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Larson
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
authors.forename: Debiao
authors.initials: D
authors.lastname: Li
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Carroll
authors.forename: Reed A
authors.initials: RA
authors.lastname: Omary
mesh_terms: D015901:Angiography, Digital Subtraction; D000800:Angioplasty, Balloon; D000818:Animals; D003287:Contrast Media; D007472:Iohexol; D016014:Linear Models; D018810:Magnetic Resonance Angiography / Q000379:methods*; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000000981:diagnostic imaging; D013552:Swine
chemical_list: D003287:Contrast Media; D007472:Iohexol