title: Automatic determination of left- and right-hand bone age in the First Zurich Longitudinal Study.
abstract: OBJECTIVE
  A more advanced bone age (BA) has been reported for the left hand relative to the right hand, while another study has found no such effect. The aim was to study the average difference of automated BoneXpert BA determination (left- vs. right-hand) for normal children, examine the precision of automatic BA and provide a BA reference for normal Caucasian children.
  
  
  METHODS
  Radiographs of both hands (age range: 2-20 years) were digitised and analysed automatically to determine Greulich-Pyle BA, producing analysis results for 3,374 left-hand and 2,752 right-hand images.
  
  
  RESULTS
  Comparison of left- and right-hand BA showed no average difference (<0.07 years, 95% confidence). The SD of the differences between left and right sides was 0.25 years for boys as well as girls, implying the precision of automated Greulich-Pyle BA determination was 0.18 years or better. Greulich-Pyle BA for boys and girls were on average 0.10 and 0.21 years below the chronological age.
  
  
  CONCLUSIONS
  The left and right hand give the same BA on average and the SD between the sides is 0.25 years, indicating an excellent precision of the automated method.
authors.affiliation: University Children's Hospital, Tübingen, Germany.
authors.forename: David D
authors.initials: DD
authors.lastname: Martin
authors.forename: Julia
authors.initials: J
authors.lastname: Neuhof
authors.forename: Oskar G
authors.initials: OG
authors.lastname: Jenni
authors.forename: Michael B
authors.initials: MB
authors.lastname: Ranke
authors.forename: Hans Henrik
authors.initials: HH
authors.lastname: Thodberg
mesh_terms: D000293:Adolescent; D000365:Age Determination by Skeleton / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006225:Hand / Q000000981:diagnostic imaging / Q000502:physiology; D050276:Hand Bones / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008137:Longitudinal Studies; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D013557:Switzerland; D055815:Young Adult