title: Peripheral arterial disease: comparison of color duplex US and contrast-enhanced MR angiography for diagnosis.
abstract: OBJECTIVE
  To prospectively compare the diagnostic accuracies of color duplex ultrasonography (US) and contrast material-enhanced magnetic resonance (MR) angiography and to assess interobserver agreement regarding contrast-enhanced MR angiographic findings in patients suspected of having peripheral arterial disease (PAD).
  
  
  METHODS
  The institutional review board approved the study, and all patients provided signed informed consent. Two hundred ninety-five patients referred for diagnostic and preinterventional work-up of PAD with duplex US also underwent gadolinium-enhanced MR angiography. Data sets were reviewed for presence or absence of 50% or greater luminal reduction, which indicated hemodynamically significant stenosis, and to determine interobserver agreement. At duplex US, a peak systolic velocity ratio of 2.5 or greater indicated significant stenosis. Primary outcome measures were differences between duplex US and contrast-enhanced MR angiography in sensitivity and specificity for detection of significant stenosis, as assessed with the McNemar test, and interobserver agreement between the two contrast-enhanced MR angiogram readings, expressed as quadratic weighted kappa values. Intraarterial digital subtraction angiography (DSA) was the reference standard.
  
  
  RESULTS
  Two hundred forty-nine patients had at least one hemodynamically significant stenotic lesion at contrast-enhanced MR angiography, duplex US, or both examinations. One hundred fifty-two patients underwent intraarterial DSA. The quadratic weighted kappa for agreement regarding the presence of 50% or greater stenosis at contrast-enhanced MR angiography was 0.89 (95% confidence interval [CI]: 0.87, 0.91). Sensitivity of duplex US was 76% (95% CI: 69%, 82%); specificity, 93% (95% CI: 91%, 95%); and accuracy, 89%. Sensitivity and specificity of contrast-enhanced MR angiography were 84% (95% CI: 78%, 89%) and 97% (95% CI: 95%, 98%), respectively; accuracy was 94%. Sensitivity (P = .002) and specificity (P = .03) of contrast-enhanced MR angiography were significantly higher.
  
  
  CONCLUSIONS
  Results of this prospective comparison between contrast-enhanced MR angiography and duplex US provide evidence that contrast-enhanced MR angiography is more sensitive and specific for diagnosis and preinterventional work-up of PAD.
authors.affiliation: Departments of Radiology, Clinical Epidemiology and Medical Technology Assessment, Epidemiology, and Vascular Surgery, Maastricht University Hospital, Peter Debijelaan 25, NL-6229 HX Maastricht, the Netherlands. leiner@rad.unimaas.nl
authors.forename: Tim
authors.initials: T
authors.lastname: Leiner
authors.forename: Alphons G H
authors.initials: AG
authors.lastname: Kessels
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Nelemans
authors.forename: G Boudewijn C
authors.initials: GB
authors.lastname: Vasbinder
authors.forename: Michiel W
authors.initials: MW
authors.lastname: de Haan
authors.forename: Peter E J H M
authors.initials: PE
authors.lastname: Kitslaar
authors.forename: Kai Yiu J A M
authors.initials: KY
authors.lastname: Ho
authors.forename: Jan H M
authors.initials: JH
authors.lastname: Tordoir
authors.forename: Joseph M A
authors.initials: JM
authors.lastname: van Engelshoven
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D003287:Contrast Media / Q000008:administration & dosage; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007383:Intermittent Claudication / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color
chemical_list: D003287:Contrast Media