title: Prospective validation of standardized, 3-dimensional, quantitative coronary computed tomographic plaque measurements using radiofrequency backscatter intravascular ultrasound as reference standard in intermediate coronary arterial lesions: results from the ATLANTA (assessment of tissue characteristics, lesion morphology, and hemodynamics by angiography with fractional flow reserve, intravascular ultrasound and virtual histology, and noninvasive computed tomography in atherosclerotic plaques) I study.
abstract: OBJECTIVE
  This study sought to determine the accuracy of 3-dimensional, quantitative measurements of coronary plaque by computed tomography angiography (CTA) against intravascular ultrasound with radiofrequency backscatter analysis (IVUS/VH).
  
  
  BACKGROUND
  Quantitative, 3-dimensional coronary CTA plaque measurements have not been validated against IVUS/VH.
  
  
  METHODS
  Sixty patients in a prospective study underwent coronary X-ray angiography, IVUS/VH, and coronary CTA. Plaque geometry and composition was quantified after spatial coregistration on segmental and slice-by-slice bases. Correlation, mean difference, and limits of agreement were determined.
  
  
  RESULTS
  There was significant correlation for all pre-specified parameters by segmental and slice-by-slice analyses (r = 0.41 to 0.84; all p < 0.001). On a segmental basis, CTA underestimated minimal lumen diameter by 21% and overestimated diameter stenosis by 39%. Minimal lumen area was overestimated on CTA by 27% but area stenosis was only underestimated by 5%. Mean difference in noncalcified plaque volume and percent and calcified plaque volume and percent were 38%, -22%, 104%, and 64%. On a slice-by-slice basis, lumen, vessel, noncalcified-, and calcified-plaque areas were overestimated on CTA by 22%, 19%, 44%, and 88%. There was significant correlation for percentage of atheroma volume (0.52 vs. 0.54; r = 0.51; p < 0.001). Compositional analysis suggested that high-density noncalcified plaque on CTA best correlated with fibrous tissue and low-density noncalcified plaque correlated with necrotic core plus fibrofatty tissue by IVUS/VH.
  
  
  CONCLUSIONS
  This is the first validation that standardized, 3-dimensional, quantitative measurements of coronary plaque correlate with IVUS/VH. Mean differences are small, whereas limits of agreement are wide. Low-density noncalcified plaque correlates with necrotic core plus fibrofatty tissue on IVUS/VH.
authors.affiliation: Piedmont Heart Institute, Atlanta, Georgia 30309, USA. szilard.voros@piedmont.org
authors.forename: Szilard
authors.initials: S
authors.lastname: Voros
authors.forename: Sarah
authors.initials: S
authors.lastname: Rinehart
authors.forename: Zhen
authors.initials: Z
authors.lastname: Qian
authors.forename: Gustavo
authors.initials: G
authors.lastname: Vazquez
authors.forename: Hunt
authors.initials: H
authors.lastname: Anderson
authors.forename: Laura
authors.initials: L
authors.lastname: Murrieta
authors.forename: Charles
authors.initials: C
authors.lastname: Wilmer
authors.forename: Harold
authors.initials: H
authors.lastname: Carlson
authors.forename: Kenneth
authors.initials: K
authors.lastname: Taylor
authors.forename: William
authors.initials: W
authors.lastname: Ballard
authors.forename: Dimitri
authors.initials: D
authors.lastname: Karmpaliotis
authors.forename: Anna
authors.initials: A
authors.lastname: Kalynych
authors.forename: Charles
authors.initials: C
authors.lastname: Brown
mesh_terms: D002114:Calcinosis / Q000000981:diagnostic imaging; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D005355:Fibrosis; D005845:Georgia; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D012015:Reference Standards; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D014057:Tomography, X-Ray Computed; D018084:Ultrasonography, Interventional