title: Ontario multidetector computed tomographic coronary angiography study: field evaluation of diagnostic accuracy.
abstract: BACKGROUND
  Computed tomographic coronary angiography (CTCA) has gained clinical acceptance for the detection of obstructive coronary artery disease. Although single-center studies have demonstrated excellent accuracy, multicenter studies have yielded variable results. The true diagnostic accuracy of CTCA in the "real world" remains uncertain. We conducted a field evaluation comparing multidetector CTCA with invasive CA (ICA) to understand CTCA's diagnostic accuracy in a real-world setting.
  
  
  METHODS
  A multicenter cohort study of patients awaiting ICA was conducted between September 2006 and June 2009. All patients had either a low or an intermediate pretest probability for coronary artery disease and underwent CTCA and ICA within 10 days. The results of CTCA and ICA were interpreted visually by local expert observers who were blinded to all clinical data and imaging results.
  
  
  RESULTS
  Using a patient-based analysis (diameter stenosis ≥50%) of 169 patients, the sensitivity, specificity, positive predictive value, and negative predictive value were 81.3% (95% confidence interval [CI], 71.0%-89.1%), 93.3% (95% CI, 85.9%-97.5%), 91.6% (95% CI, 82.5%-96.8%), and 84.7% (95% CI, 76.0%-91.2%), respectively; the area under receiver operating characteristic curve was 0.873. The diagnostic accuracy varied across centers (P < .001), with a sensitivity, specificity, positive predictive value, and negative predictive value ranging from 50.0% to 93.2%, 92.0% to 100%, 84.6% to 100%, and 42.9% to 94.7%, respectively.
  
  
  CONCLUSIONS
  Compared with ICA, CTCA appears to have good accuracy; however, there was variability in diagnostic accuracy across centers. Factors affecting institutional variability need to be better understood before CTCA is universally adopted. Additional real-world evaluations are needed to fully understand the impact of CTCA on clinical care.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00371891.
authors.affiliation: Department of Radiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Benjamin J W
authors.initials: BJ
authors.lastname: Chow
authors.forename: Michael R
authors.initials: MR
authors.lastname: Freeman
authors.forename: James M
authors.initials: JM
authors.lastname: Bowen
authors.forename: Leslie
authors.initials: L
authors.lastname: Levin
authors.forename: Robert B
authors.initials: RB
authors.lastname: Hopkins
authors.forename: Yves
authors.initials: Y
authors.lastname: Provost
authors.forename: Jean-Eric
authors.initials: JE
authors.lastname: Tarride
authors.forename: Carole
authors.initials: C
authors.lastname: Dennie
authors.forename: Eric A
authors.initials: EA
authors.lastname: Cohen
authors.forename: Dan
authors.initials: D
authors.lastname: Marcuzzi
authors.forename: Robert
authors.initials: R
authors.lastname: Iwanochko
authors.forename: Alan R
authors.initials: AR
authors.lastname: Moody
authors.forename: Narinder
authors.initials: N
authors.lastname: Paul
authors.forename: John D
authors.initials: JD
authors.lastname: Parker
authors.forename: Daria J
authors.initials: DJ
authors.lastname: O'Reilly
authors.forename: Feng
authors.initials: F
authors.lastname: Xie
authors.forename: Ron
authors.initials: R
authors.lastname: Goeree
mesh_terms: D019540:Area Under Curve; D017023:Coronary Angiography / Q000592:standards*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000592:standards*