title: Proposal of new upper airway margins in children assessed by CBCT.
abstract: OBJECTIVE
  Recently, studies have performed three-dimensional analyses of upper airways in children. However, there was a lack of airway delineation according to anatomical boundaries and/or easily mobile soft-tissue landmarks were used. The aim of the present study was to define new upper airway margins in children on CBCT according to anatomical bony landmarks and to validate the method.
  
  
  METHODS
  25 scans were randomly selected from a larger database containing CBCT scans of children prior to orthodontic treatment (14 girls and 11 boys; mean age, 10.9 ± 2.5 years). Scans were evaluated by two observers. Specific head positioning and virtual orientation protocols were adopted and greyscale thresholding was established for each patient. Volume and minimum cross-sectional area of the oropharynx were calculated. Intra- and interobserver reliability were assessed by reassessment of the CBCTs 2 weeks later.
  
  
  RESULTS
  The new airway margins were defined superiorly by a line passing through the palatal plane (anterior nasal spine to posterior nasal spine) extending to the posterior wall of the pharynx, inferiorly by a line passing from the anterosuperior edge of C4 to menton, anteriorly by a line passing from the soft palate to menton, posteriorly and laterally by the respective pharyngeal walls. Method error for airway volume and minimal cross-sectional area was ≤2.00%, and intra- and interobserver reliability ranged from 0.99 to 1.00.
  
  
  CONCLUSIONS
  The proposed protocol utilizes easily identifiable bony landmarks to delineate the upper airway on cone beam scans of children and was found to be reliable and reproducible.
authors: 1 James Cook University, Cairns, QLD, Australia.
authors: S
authors: S
authors: Anandarajah
authors: 1 James Cook University, Cairns, QLD, Australia.
authors: Y
authors: Y
authors: Abdalla
authors: 2 Department of Dental Radiology, Queensland X-ray, Brisbane, Australia.
authors: R
authors: R
authors: Dudhia
authors: 3 Section of Orthodontics, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors: L
authors: L
authors: Sonnesen
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002648:Child; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D009960:Oropharynx / Q000000981:diagnostic imaging*; D009971:Orthodontics, Corrective; D056888:Patient Positioning; D015203:Reproducibility of Results
keywords: children; cone beam computed tomography; upper airway; validation