title: Reproducibility, accuracy, and predictors of accuracy for the detection of coronary atherosclerotic plaque composition by computed tomography: an ex vivo comparison to intravascular ultrasound.
abstract: OBJECTIVE
  To determine the reproducibility, accuracy, and predictors of accuracy of computed tomography (CT) angiography to detect and characterize coronary atherosclerotic plaque as compared with intravascular ultrasound.
  
  
  METHODS
  Ten ex vivo human coronary arteries were imaged in a moving phantom by dual-source CT (collimation: 0.6 mm, reconstructed slice thickness: 0.4 mm) and intravascular ultrasound (IVUS). Coregistered cross-sections were assessed at 0.4 mm intervals for the presence and composition of atherosclerotic plaque (noncalcified, mixed, and calcified) on CT and IVUS by independent readers to determine reader agreement and diagnostic accuracy. Quantitative measurements of lumen and plaque area, plaque eccentricity, and intimal thickness on IVUS were used to determine predictors for the detection of noncalcified plaque by CT.
  
  
  RESULTS
  Within 1002 coregistered cross-sections, the interobserver agreement to detect plaque on CT was K = 0.48, K = 0.42, and K = 1.00 for noncalcified, mixed, and calcified plaque; respectively. The sensitivity and specificity of CT was 57% out of 84% for noncalcified, 32% of 92% for mixed, and 56% of 93% for calcified plaque when compared with IVUS; respectively. Misclassification occurred in 68% of mixed and 43% of noncalcified plaques. The odds of detecting noncalcified plaque in CT independently increased by 56% (95% CI: 47%-77%, P < 0.0001) with every 0.1 mm increase in maximum intimal thickness as measured by IVUS. Detection rate for noncalcified plaques was poor for plaques <1 mm (36%) but excellent for plaques >1 mm maximal intimal thickness (90%).
  
  
  CONCLUSIONS
  Reader agreement and diagnostic accuracy for the detection of coronary atherosclerotic plaque vary with plaque composition. Intimal thickness independently predicts detection of noncalcified plaque by CT with excellent sensitivity for >1 mm thick plaques.
authors.affiliation: Cardiac MRI PET CT Program, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02144, USA.
authors.forename: Alina G
authors.initials: AG
authors.lastname: van der Giessen
authors.forename: Michael H
authors.initials: MH
authors.lastname: Toepker
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Donelly
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Schlett
authors.forename: Christopher
authors.initials: C
authors.lastname: Raffle
authors.forename: Thomas
authors.initials: T
authors.lastname: Irlbeck
authors.forename: Hang
authors.initials: H
authors.lastname: Lee
authors.forename: Theo
authors.initials: T
authors.lastname: van Walsum
authors.forename: Pal
authors.initials: P
authors.lastname: Maurovich-Horvat
authors.forename: Frank J H
authors.initials: FJ
authors.lastname: Gijsen
authors.forename: Jolanda J
authors.initials: JJ
authors.lastname: Wentzel
authors.forename: Udo
authors.initials: U
authors.lastname: Hoffmann
mesh_terms: D000368:Aged; D019540:Area Under Curve; D016001:Confidence Intervals; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods; D018084:Ultrasonography, Interventional / Q000295:instrumentation*