title: Concordance of coronary artery calcium estimates between MDCT and electron beam tomography.
abstract: OBJECTIVE
  The objective of our study was to compare MDCT with electron beam tomography (EBT) for the quantification of coronary artery calcification (CAC).
  
  
  METHODS
  Sixty-eight patients underwent both MDCT and EBT within 2 months for the quantification of CAC. The images were scored in a blinded fashion and independently by two observers with a minimum of 7 days between the interpretations of images obtained from one scanner type to the other.
  
  
  RESULTS
  Presence versus absence of CAC was discordant by EBT versus MDCT in 6% (n = 4) of the cases by observer 1, with one of these cases also discordant by observer 2. All cases except one (aortic calcium misidentified as CAC) were among those with a mean Agatston score of less than 5 present on EBT but absent on MDCT. EBT and MDCT scores correlated well (r = 0.98-0.99). The relative median variability between EBT and MDCT for the Agatston score was 24% for observer 1 and 27% for observer 2 and was 18% and 14%, respectively, for volume score (average for both observers: 27% for Agatston score and 16% for volume score). Scores were higher for EBT than MDCT in approximately half of the cases, with little systematic difference between the two (median EBT-MDCT difference: Agatston score, -0.55; volume score, 3.4 mm3). The absolute median difference averaged for the two observers was 28.75 for the Agatston score and 15.4 mm3 for the volume score.
  
  
  CONCLUSIONS
  Differences in CAC measurements using EBT and MDCT are similar to interscan differences in CAC measurements previously reported for EBT or for other MDCT scanners individually.
authors.affiliation: Department of Imaging, Division of Nuclear Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Daniell
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Wong
authors.forename: John D
authors.initials: JD
authors.lastname: Friedman
authors.forename: Nachum
authors.initials: N
authors.lastname: Ben-Yosef
authors.forename: Romalisa
authors.initials: R
authors.lastname: Miranda-Peats
authors.forename: Sean W
authors.initials: SW
authors.lastname: Hayes
authors.forename: Xingping
authors.initials: X
authors.lastname: Kang
authors.forename: Maria G
authors.initials: MG
authors.lastname: Sciammarella
authors.forename: Ling
authors.initials: L
authors.lastname: de Yang
authors.forename: Guido
authors.initials: G
authors.lastname: Germano
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Berman
mesh_terms: D000368:Aged; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000473:pathology; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*