title: Cardiac valve calcifications on low-dose unenhanced ungated chest computed tomography: inter-observer and inter-examination reliability, agreement and variability.
abstract: OBJECTIVE
  To determine inter-observer and inter-examination variability for aortic valve calcification (AVC) and mitral valve and annulus calcification (MC) in low-dose unenhanced ungated lung cancer screening chest computed tomography (CT).
  
  
  METHODS
  We included 578 lung cancer screening trial participants who were examined by CT twice within 3 months to follow indeterminate pulmonary nodules. On these CTs, AVC and MC were measured in cubic millimetres. One hundred CTs were examined by five observers to determine the inter-observer variability. Reliability was assessed by kappa statistics (κ) and intra-class correlation coefficients (ICCs). Variability was expressed as the mean difference ± standard deviation (SD).
  
  
  RESULTS
  Inter-examination reliability was excellent for AVC (κ = 0.94, ICC = 0.96) and MC (κ = 0.95, ICC = 0.90). Inter-examination variability was 12.7 ± 118.2 mm(3) for AVC and 31.5 ± 219.2 mm(3) for MC. Inter-observer reliability ranged from κ = 0.68 to κ = 0.92 for AVC and from κ = 0.20 to κ = 0.66 for MC. Inter-observer ICC was 0.94 for AVC and ranged from 0.56 to 0.97 for MC. Inter-observer variability ranged from -30.5 ± 252.0 mm(3) to 84.0 ± 240.5 mm(3) for AVC and from -95.2 ± 210.0 mm(3) to 303.7 ± 501.6 mm(3) for MC.
  
  
  CONCLUSIONS
  AVC can be quantified with excellent reliability on ungated unenhanced low-dose chest CT, but manual detection of MC can be subject to substantial inter-observer variability. Lung cancer screening CT may be used for detection and quantification of cardiac valve calcifications.
  
  
  CONCLUSIONS
  • Low-dose unenhanced ungated chest computed tomography can detect cardiac valve calcifications. • However, calcified cardiac valves are not reported by most radiologists. • Inter-observer and inter-examination variability of aortic valve calcifications is sufficient for longitudinal studies. • Volumetric measurement variability of mitral valve and annulus calcifications is substantial.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, E01.132, 3508 GA, Utrecht, The Netherlands.
authors.forename: Robbert W
authors.initials: RW
authors.lastname: van Hamersvelt
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Willemink
authors.forename: Richard A P
authors.initials: RA
authors.lastname: Takx
authors.forename: Anouk L M
authors.initials: AL
authors.lastname: Eikendal
authors.forename: Ricardo P J
authors.initials: RP
authors.lastname: Budde
authors.forename: Tim
authors.initials: T
authors.lastname: Leiner
authors.forename: Christian P
authors.initials: CP
authors.lastname: Mol
authors.forename: Ivana
authors.initials: I
authors.lastname: Isgum
authors.forename: Pim A
authors.initials: PA
authors.lastname: de Jong
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000473:pathology*; D001024:Aortic Valve Stenosis / Q000150:complications / Q000000981:diagnostic imaging*; D002114:Calcinosis / Q000150:complications / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D004307:Dose-Response Relationship, Radiation; D055088:Early Detection of Cancer; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed