title: A prospective comparison of duplex ultrasonography, captopril renography, MRA, and CTA in assessing renal artery stenosis.
abstract: OBJECTIVE
  To prospectively compare the diagnostic accuracy of duplex ultrasonography, captopril renography, computed tomography angiography (CTA), and 3D Gd magnetic resonance angiography (MRA) in diagnosing hemodynamically significant renal artery stenosis (RAS).
  
  
  METHODS
  The standard of reference was measurement of transstenotic pressure gradient. Fifty-eight hypertensive patients with suspicion of RAS were evaluated, when possible, by all five techniques. Sensitivity and specificity to detect RAS were compared for each technique on both a patient and kidney basis. Discrepancies were evaluated separately and classified as borderline, method dependent, or operator dependent.
  
  
  RESULTS
  The prevalence of RAS was 77%. The sensitivity/specificity of ultrasonography, captopril renography, CTA, and MRA in detecting kidneys with RAS was 73/71%, 52/63%, 94/62%, and 93/91%, respectively. Ultrasonography had a significantly lower sensitivity than CTA and MRA (P<0.001) but higher than captopril renography (P = 0.013). Borderline RAS was the main cause for discrepancies.
  
  
  CONCLUSIONS
  MRA and CTA were significantly better than duplex ultrasonography and captopril renography in detecting hemodynamically significant RAS. The ultrasonography criteria for RAS based on the evaluation of renal peak systolic velocity and renal/aortic ratio are questionable. Captopril renography cannot be recommended for assessing RAS.
authors.affiliation: Department of Radiology, Uppsala University Hospital, Uppsala, Sweden. hampus.eklof@radiol.uu.se
authors.forename: H
authors.initials: H
authors.lastname: Eklöf
authors.forename: H
authors.initials: H
authors.lastname: Ahlström
authors.forename: A
authors.initials: A
authors.lastname: Magnusson
authors.forename: L-G
authors.initials: LG
authors.lastname: Andersson
authors.forename: B
authors.initials: B
authors.lastname: Andrén
authors.forename: A
authors.initials: A
authors.lastname: Hägg
authors.forename: D
authors.initials: D
authors.lastname: Bergqvist
authors.forename: R
authors.initials: R
authors.lastname: Nyman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D002216:Captopril; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011866:Radioisotope Renography; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D018616:Ultrasonography, Doppler, Duplex
chemical_list: D002216:Captopril