title: Comparison of endoscopic versus 3D CT derived airway measurements.
abstract: OBJECTIVE
  To understand: 1) how endoscopic airway measurements compare to three-dimensional (3D) CT derived measurements; 2) where each technique is potentially useful; and 3) where each has limitations.
  
  
  METHODS
  Compare airway diameters and cross-sectional areas from endoscopic images and CT derived 3D reconstructions.
  
  
  METHODS
  Videobronchoscopy was performed and recorded on an adult-sized commercially available airway mannequin. At various levels, cross-sectional areas were measured from still video frames using a referent placed via the biopsy port. A 3D reconstruction was generated from a high resolution CT of the mannequin; planar sections were cut at similar cross-sectional levels; and cross-sectional areas were obtained.
  
  
  RESULTS
  At three levels of mechanically generated tracheal stricture, the differences between the endoscopic measurement and CT-derived cross-sectional area were 1%, 0%, and 7% (1.8, 0.8, and 14 mm²). At the vocal folds, the difference was 9% (7.8 mm²). The tip of the epiglottis and width of the epiglottis differed by 27% and 10% (18.73 mm², 0.40 mm). The airway measurements at the base of tongue, minimal cross-sectional area of the pharynx, and choana differed by 26%, 36%, and 30% (101.40 mm², 36.67 mm², 122.71 mm²).
  
  
  CONCLUSIONS
  Endoscopy is an effective tool for obtaining airway measurements compared with 3D reconstructions derived from CT. Concordance is best in geometrically simple areas where the entire cross-section measured is visible within one field of view (trachea, round; vocal folds, triangular) versus geometrically complex areas that encompass more than one field of view (i.e. pharynx, choana).
authors.forename: Hollin E
authors.initials: HE
authors.lastname: Calloway
authors.forename: Julia S
authors.initials: JS
authors.lastname: Kimbell
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Davis
authors.forename: George Z
authors.initials: GZ
authors.lastname: Retsch-Bogart
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Pitkin
authors.forename: Kathleen
authors.initials: K
authors.lastname: Abode
authors.forename: Richard
authors.initials: R
authors.lastname: Superfine
authors.forename: Carlton J
authors.initials: CJ
authors.lastname: Zdanski
mesh_terms: D000328:Adult; D058109:Airway Management; D000403:Airway Resistance; D001999:Bronchoscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008348:Manikins; D008953:Models, Anatomic; D012119:Respiration; D012137:Respiratory System / Q000000981:diagnostic imaging* / Q000473:pathology; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods; D014135:Tracheal Stenosis / Q000000981:diagnostic imaging* / Q000473:pathology; D014741:Video Recording