title: Automatic determination of Greulich and Pyle bone age in healthy Dutch children.
abstract: BACKGROUND
  Bone age (BA) assessment is a routine procedure in paediatric radiology, for which the Greulich and Pyle (GP) atlas is mostly used. There is rater variability, but the advent of automatic BA determination eliminates this.
  
  
  OBJECTIVE
  To validate the BoneXpert method for automatic determination of skeletal maturity of healthy children against manual GP BA ratings.
  
  
  METHODS
  Two observers determined GP BA with knowledge of the chronological age (CA). A total of 226 boys with a BA of 3-17 years and 179 girls with a BA of 3-15 years were included in the study. BoneXpert's estimate of GP BA was calibrated to agree on average with the manual ratings based on several studies, including the present study.
  
  
  RESULTS
  Seven subjects showed a deviation between manual and automatic BA in excess of 1.9 years. They were re-rated blindly by two raters. After correcting these seven ratings, the root mean square error between manual and automatic rating in the 405 subjects was 0.71 years (range 0.66-0.76 years, 95% CI). BoneXpert's GP BA is on average 0.28 and 0.20 years behind the CA for boys and girls, respectively.
  
  
  CONCLUSIONS
  BoneXpert is a robust method for automatic determination of BA.
authors.affiliation: Department of Radiology, Academic Medical Center Amsterdam, Amsterdam Zuid-Oost, The Netherlands. r.r.vanrijn@amc.uva.nl
authors.forename: Rick R
authors.initials: RR
authors.lastname: van Rijn
authors.forename: Maarten H
authors.initials: MH
authors.lastname: Lequin
authors.forename: Hans Henrik
authors.initials: HH
authors.lastname: Thodberg
mesh_terms: D000293:Adolescent; D000365:Age Determination by Skeleton / Q000295:instrumentation* / Q000379:methods*; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity