title: Reproducibility of electron-beam CT measures of aortic valve calcification.
abstract: OBJECTIVE
  The authors performed this study to establish the interscan, interobserver, and intraobserver reproducibility of aortic valve calcification (AVC) measurements obtained with electron-beam computed tomography (CT).
  
  
  METHODS
  The authors evaluated electron-beam CT scans from all patients who had undergone two serial examinations on the same day as part of a study of coronary artery calcification reproducibility. In patients in whom aortic valve calcium was identified at electron-beam CT, AVC scores were measured with both the Agatston and the volumetric methods, which were developed previously to quantify coronary calcium.
  
  
  RESULTS
  Forty-four asymptomatic patients (mean age, 66 years +/- 9) with AVC at electron-beam CT were included in the analyses. AVC score reproducibility was excellent with both the Agatston and the volumetric methods (R2 = 0.99, P = .0001 for both), with median interscan variabilities of 7% and 6.2%, respectively. Interscan reproducibility was similar, whether the analysis included all scans or was restricted to those with scores greater than 10 or greater than 30. For the volumetric method, the median interobserver variability was 5% and the median intraobserver variability was 1%.
  
  
  CONCLUSIONS
  The low interscan, interobserver, and intraobserver variabilities at electron-beam CT suggest that this method should be useful for the noninvasive monitoring of AVC changes over time and for assessing the efficacy of therapies aimed at slowing AVC accumulation.
authors.affiliation: Harbor-UCLA Research and Education Institute, Torrance, Calif, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Budoff
authors.forename: Songshou
authors.initials: S
authors.lastname: Mao
authors.forename: Junichiro
authors.initials: J
authors.lastname: Takasu
authors.forename: David M
authors.initials: DM
authors.lastname: Shavelle
authors.forename: Xue-Qiao
authors.initials: XQ
authors.lastname: Zhao
authors.forename: Kevin D
authors.initials: KD
authors.lastname: O'Brien
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000473:pathology*; D002114:Calcinosis / Q000175:diagnosis* / Q000453:epidemiology; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006349:Heart Valve Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed