title: Three-dimensional computed tomography cephalometry of plagiocephaly: asymmetry and shape analysis.
abstract: OBJECTIVE
  To investigate facial asymmetry associated with both deformational and synostotic plagiocephaly and to identify variables based on skeletal landmarks that distinguish the conditions and quantify severity.
  
  
  METHODS
  Retrospective, cross sectional.
  
  
  METHODS
  Australian Craniofacial Unit, Adelaide.
  
  
  METHODS
  Proportional differences between bilateral distances and principal component (PC) analysis of the skeletal landmarks.
  
  
  METHODS
  The three-dimensional positions of 78 osseous landmarks were determined from computed tomography (CT) scans of 21 patients with deformational plagiocephaly (DP), 20 patients with unilateral coronal synostosis (UCS), and 2 patients with unilateral lambdoid synostosis (ULS).
  
  
  RESULTS
  For both DP and UCS, significant asymmetry was found for the orbital depths, mandibular lengths, maxillary depths, zygomatic arch lengths, lateral base of the parietal bone, and the angle between the anterior and the posterior cranial base projected onto the axial plane. The small sample size for ULS precluded definitive statistical statements but allowed some useful comparisons with the other conditions. The first three PC scores were able to distinguish among the three conditions and which side was affected.
  
  
  CONCLUSIONS
  The asymmetry of the cranial base and facial structures, arising from localized abnormality or deformational forces in either the frontal or the occipital regions, can be quantified by a plethora of bilateral features or summarized by PC analysis.
authors.affiliation: Australian Craniofacial Institute, Women's and Children's Hospital, 72 King William Road, North Adelaide, SA 5006, Australia. david.netherway@adelaide.edu.au
authors.forename: D J
authors.initials: DJ
authors.lastname: Netherway
authors.forename: A H
authors.initials: AH
authors.lastname: Abbott
authors.forename: N
authors.initials: N
authors.lastname: Gulamhuseinwala
authors.forename: K L
authors.initials: KL
authors.lastname: McGlaughlin
authors.forename: P J
authors.initials: PJ
authors.lastname: Anderson
authors.forename: G C
authors.initials: GC
authors.lastname: Townsend
authors.forename: D J
authors.initials: DJ
authors.lastname: David
mesh_terms: D002508:Cephalometry / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005145:Face / Q000000981:diagnostic imaging; D005146:Facial Asymmetry / Q000000981:diagnostic imaging*; D006257:Head / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007223:Infant; D049068:Plagiocephaly, Nonsynostotic / Q000000981:diagnostic imaging*; D025341:Principal Component Analysis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed