title: Magnetic resonance angiography for the diagnosis of renal artery stenosis: a meta-analysis.
abstract: OBJECTIVE
  To review the published literature comparing the diagnostic accuracy of magnetic resonance angiography (MRA) with and without gadolinium in diagnosing renal artery stenosis, using catheter angiography as reference.
  
  
  METHODS
  A meta-analysis was performed of English language articles identified by computer search using PubMed/MEDLINE, followed by extensive bibliography review from 1985 to May 2001. Inclusion criteria were: (1) blinded comparison with catheter angiography; (2)indication for MRA stated; (3) clear descriptions of imaging techniques; and (4) interval between MRA and catheter angiography < 3 months and only the largest of all studies from one centre was selected in the analysis.
  
  
  RESULTS
  A total of 39 studies were identified, of which 25 met the inclusion criteria. The number of patients included in the meta-analysis was 998: 499 with non-enhanced MRA and 499 with gadolinium-enhanced MRA. The sensitivity and specificity of non-enhanced MRA were 94% (95% CI: 90-97%) and 85% (95% CI: 82-87%), respectively. For gadolinium-enhanced MRA sensitivity was 97% (95% CI: 93-98%) and specificity was 93% (95% CI: 91-95%). Thus, specificity and positive predictive value were significantly better for gadolinium-enhanced MRA (P < 0.001). Accessory renal arteries were depicted better by gadolinium-enhanced MRA (82%; 95% CI: 75-87%) than non-gadolinium MRA (49%; 95% CI: 42-60%) (P < 0.001).
  
  
  CONCLUSIONS
  Gadolinium-enhanced MRA may replace arteriography in most patients with suspected renal artery stenosis, and has major advantages in that it is non-invasive, avoids ionizing radiation and uses a non-nephrotoxic contrast agent.
authors.affiliation: Section of Academic Radiology, University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK.
authors.forename: K T
authors.initials: KT
authors.lastname: Tan
authors.forename: E J R
authors.initials: EJ
authors.lastname: van Beek
authors.forename: P W G
authors.initials: PW
authors.lastname: Brown
authors.forename: O M
authors.initials: OM
authors.lastname: van Delden
authors.forename: J
authors.initials: J
authors.lastname: Tijssen
authors.forename: L E
authors.initials: LE
authors.lastname: Ramsay
mesh_terms: D003287:Contrast Media; D005682:Gadolinium; D006801:Humans; D018810:Magnetic Resonance Angiography; D011859:Radiography; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D005682:Gadolinium