title: Quantification of plagiocephaly and brachycephaly in infants using a digital photographic technique.
abstract: OBJECTIVE
  The aims of the study were: (1) to develop a technique to quantify plagiocephaly that is safe, accurate, objective, easy to use, well tolerated, and inexpensive; and (2) to compare this method with tracings from a flexicurve ruler.
  
  
  METHODS
  A case-control study of 31 case infants recruited from outpatient plagiocephaly clinics and 29 control infants recruited from other pediatric outpatient clinics.
  
  
  METHODS
  Infants in the study had been diagnosed with nonsynostotic plagiocephaly or brachycephaly and were between 2 and 12 months old.
  
  
  METHODS
  Infants' head shapes were measured using (a) digital photographs of a head circumference band and (b) a flexicurve ruler. Flexicurve tracings were scanned, and both the digital photos and the scanned flexicurve tracings were analyzed using a custom-written computer program.
  
  
  METHODS
  The oblique cranial length ratio was used to quantify cranial asymmetry, and the cephalic index was used to quantify the degree of brachycephaly.
  
  
  RESULTS
  The infants tolerated the photo technique better than the flexicurve. Also, mothers preferred the photo technique. There was less within-subject variance for the photos than for the flexicurve measurements. The results suggested that an oblique cranial length ratio of >or= 106% can define plagiocephaly and that a cephalic index of >or= 93% can define brachycephaly.
  
  
  CONCLUSIONS
  The photographic technique was better accepted and more repeatable than the flexicurve measuring system. We propose that "normal" head shape is indicated in infants with both an oblique cranial length ratio of less than 106% and a cephalic index of less than 93%.
authors.affiliation: Department of Pediatrics, University of Auckland, New Zealand. bl.hutchison@auckland.ac.nz
authors.forename: B Lynne
authors.initials: BL
authors.lastname: Hutchison
authors.forename: Luke A D
authors.initials: LA
authors.lastname: Hutchison
authors.forename: John M D
authors.initials: JM
authors.lastname: Thompson
authors.forename: Ed A
authors.initials: EA
authors.lastname: Mitchell
mesh_terms: D016022:Case-Control Studies; D002508:Cephalometry / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005006:Ethnicity; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D008297:Male; D010781:Photography / Q000379:methods* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012886:Skull / Q000002:abnormalities* / Q000473:pathology; D012984:Software; D013997:Time Factors