title: Combined CT coronary angiography and stress myocardial perfusion imaging for hemodynamically significant stenoses in patients with suspected coronary artery disease: a comparison with fractional flow reserve.
abstract: OBJECTIVE
  We sought to determine the accuracy of combined coronary computed tomography angiography (CTA) and computed tomography stress myocardial perfusion imaging (CTP) in the detection of hemodynamically significant stenoses using fractional flow reserve (FFR) as a reference standard in patients with suspected coronary artery disease.
  
  
  BACKGROUND
  CTP can be qualitatively assessed by visual interpretation or quantified by the transmural perfusion ratio determined as the ratio of subendocardial to subepicardial contrast attenuation. The incremental value of each technique in addition to coronary CTA to detect hemodynamically significant stenoses is not known.
  
  
  METHODS
  Forty symptomatic patients underwent FFR and 320-detector computed tomography assessment including coronary CTA and CTP. Myocardial perfusion was assessed using the transmural perfusion ratio and visual perfusion assessment. Computed tomography images were assessed by consensus of 2 observers. Transmural perfusion ratio <0.99 was used as the threshold for abnormal perfusion. FFR ≤0.8 indicated hemodynamically significant stenoses.
  
  
  RESULTS
  Coronary CTA detected FFR-significant stenoses with 95% sensitivity and 78% specificity. The additional use of visual perfusion assessment and the transmural perfusion ratio both increased the specificity to 95%, with sensitivity of 87% and 71%, respectively. The area under the receiver-operating characteristic curve for coronary CTA + visual perfusion assessment was significantly higher than both coronary CTA (0.93 vs. 0.85, p = 0.0003) and coronary CTA + the transmural perfusion ratio (0.93 vs. 0.79, p = 0.0003). Per-vessel and per-patient accuracy for coronary CTA, coronary CTA + the transmural perfusion ratio, and coronary CTA + visual perfusion assessment was 83% and 83%, 87% and 92%, and 92% and 95%, respectively.
  
  
  CONCLUSIONS
  In suspected coronary artery disease, combined coronary CTA + CTP identifies patients with hemodynamically significant stenoses with >90% accuracy compared with FFR. When interpreted with coronary CTA, visual perfusion assessment provided superior incremental value in the detection of FFR-significant stenoses compared with the quantitative transmural perfusion ratio assessment.
authors.affiliation: Monash Cardiovascular Research Centre, MonashHeart, Department of Medicine, Monash Medical Centre, Southern Health and Monash University, Melbourne, Victoria, Australia.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Ko
authors.forename: James D
authors.initials: JD
authors.lastname: Cameron
authors.forename: Michael
authors.initials: M
authors.lastname: Leung
authors.forename: Ian T
authors.initials: IT
authors.lastname: Meredith
authors.forename: Darryl P
authors.initials: DP
authors.lastname: Leong
authors.forename: Paul R
authors.initials: PR
authors.lastname: Antonis
authors.forename: Marcus
authors.initials: M
authors.lastname: Crossett
authors.forename: John
authors.initials: J
authors.lastname: Troupis
authors.forename: Richard
authors.initials: R
authors.lastname: Harper
authors.forename: Yuvaraj
authors.initials: Y
authors.lastname: Malaiapan
authors.forename: Sujith K
authors.initials: SK
authors.lastname: Seneviratne
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity