title: Hemodynamically significant atherosclerotic renal artery stenosis: MR angiographic features.
abstract: OBJECTIVE
  To identify magnetic resonance (MR) angiographic features of hemodynamically significant renal artery stenosis.
  
  
  METHODS
  Forty-seven patients underwent MR angiography of the renal arteries, including T1-weighted spin-echo and three-dimensional gadolinium-enhanced spoiled gradient-echo and three-dimensional phase-contrast pulse sequences, followed by renal revascularization. Thirty-five patients (52 arteries) were identified who benefited from renal revascularization, which indicated that they had hemodynamically significant renal artery stenoses. Kidney length, cortical thickness, parenchymal enhancement, and poststenotic dilatation were measured. Arteries were also examined for signal drop-out (dephasing) on phase-contrast angiograms; dephasing was considered severe if the stenotic artery appeared occluded on phase-contrast angiograms.
  
  
  RESULTS
  Poststenotic dilatation of greater than 20% was present in 36 (59%) of 52 hemodynamically significant renal artery stenoses, and severe dephasing was present in 45 (87%) of 52. In patients with unilateral hemodynamically significant stenosis or occlusion, mean ischemic kidney length was reduced to 9.3 cm compared with 10.7 cm for the contralateral normal kidney (P = .009), mean parenchymal thickness was reduced (1.2 vs 1.7 cm; P < .001), and mean parenchymal enhancement was 15% less on the ischemic side (P = .05). Severe dephasing on phase-contrast angiograms was present in nine (75%) of 12 unilateral hemodynamically significant stenoses but in only one contralateral normal renal artery (P < .001).
  
  
  CONCLUSIONS
  MR angiography depicts features of renal artery stenosis that are markers of hemodynamic significance.
authors.affiliation: Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0030, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Prince
authors.forename: S O
authors.initials: SO
authors.lastname: Schoenberg
authors.forename: J S
authors.initials: JS
authors.lastname: Ward
authors.forename: F J
authors.initials: FJ
authors.lastname: Londy
authors.forename: T W
authors.initials: TW
authors.lastname: Wakefield
authors.forename: J C
authors.initials: JC
authors.lastname: Stanley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001161:Arteriosclerosis / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D019786:Gadolinium DTPA; D006439:Hemodynamics; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives; D012077:Renal Artery / Q000473:pathology; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; C064925:gadodiamide; D005682:Gadolinium; D019786:Gadolinium DTPA