title: Duplex ultrasonography, magnetic resonance angiography, and computed tomography angiography for diagnosis and assessment of symptomatic, lower limb peripheral arterial disease: systematic review.
abstract: OBJECTIVE
  To determine the diagnostic accuracy of duplex ultrasonography, magnetic resonance angiography, and computed tomography angiography, alone or in combination, for the assessment of lower limb peripheral arterial disease; to evaluate the impact of these assessment methods on management of patients and outcomes; and to evaluate the evidence regarding attitudes of patients to these technologies and summarise available data on adverse events.
  
  
  METHODS
  Systematic review.
  
  
  METHODS
  Searches of 11 electronic databases (to April 2005), six journals, and reference lists of included papers for relevant studies. Two reviewers independently selected studies, extracted data, and assessed quality. Diagnostic accuracy studies were assessed for quality with the QUADAS checklist.
  
  
  RESULTS
  107 studies met the inclusion criteria; 58 studies provided data on diagnostic accuracy, one on outcomes in patients, four on attitudes of patients, and 44 on adverse events. Quality assessment highlighted limitations in the methods and quality of reporting. Most of the included studies reported results by arterial segment, rather than by limb or by patient, which does not account for the clustering of segments within patients, so specificities may be overstated. For the detection of stenosis of 50% or more in a lower limb vessel, contrast enhanced magnetic resonance angiography had the highest diagnostic accuracy with a median sensitivity of 95% (range 92-99.5%) and median specificity of 97% (64-99%). The results were 91% (89-99%) and 91% (83-97%) for computed tomography angiography and 88% (80-98%) and 96% (89-99%) for duplex ultrasonography. A controlled trial reported no significant differences in outcomes in patients after treatment plans based on duplex ultrasonography alone or conventional contrast angiography alone, though in 22% of patients supplementary contrast angiography was needed to form a treatment plan. The limited evidence available suggested that patients preferred magnetic resonance angiography (with or without contrast) to contrast angiography, with half expressing no preference between magnetic resonance angiography or duplex ultrasonography (among patients with no contraindications for magnetic resonance angiography, such as claustrophobia). Where data on adverse events were available, magnetic resonance angiography was associated with the highest proportion of adverse events, but these were mild. The most severe adverse events, although rare, were mainly associated with contrast angiography.
  
  
  CONCLUSIONS
  Contrast enhanced magnetic resonance angiography seems to be more specific than computed tomography angiography (that is, better at ruling out stenosis over 50%) and more sensitive than duplex ultrasonography (that is, better at ruling in stenosis over 50%) and was generally preferred by patients over contrast angiography. Computed tomography angiography was also preferred by patients over contrast angiography; no data on patients' preference between duplex ultrasonography and contrast angiography were available. Where available, contrast enhanced magnetic resonance angiography might be a viable alternative to contrast angiography.
authors.affiliation: Centre for Reviews and Dissemination, University of York, York YO10 5DD. rc14@york.ac.uk
authors.forename: Ros
authors.initials: R
authors.lastname: Collins
authors.forename: Jane
authors.initials: J
authors.lastname: Burch
authors.forename: Gillian
authors.initials: G
authors.lastname: Cranny
authors.forename: Raquel
authors.initials: R
authors.lastname: Aguiar-Ibáñez
authors.forename: Dawn
authors.initials: D
authors.lastname: Craig
authors.forename: Kath
authors.initials: K
authors.lastname: Wright
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Berry
authors.forename: Michael
authors.initials: M
authors.lastname: Gough
authors.forename: Jos
authors.initials: J
authors.lastname: Kleijnen
authors.forename: Marie
authors.initials: M
authors.lastname: Westwood
mesh_terms: D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D003287:Contrast Media; D006801:Humans; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000592:standards; D017060:Patient Satisfaction; D016491:Peripheral Vascular Diseases / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000592:standards; D018608:Ultrasonography, Doppler / Q000592:standards
chemical_list: D003287:Contrast Media