title: Objective characterization of airway dimensions using image processing.
abstract: OBJECTIVE
  With the evolution of medical and surgical management for pediatric airway disorders, the development of easily translated techniques of measuring airway dimensions can improve the quantification of outcomes of these interventions. We have developed a technique that improves the ability to characterize endoscopic airway dimensions using common bronchoscopic equipment and an open-source image-processing platform.
  
  
  METHODS
  We validated our technique of Endoscopic Airway Measurement (EAM) using optical instruments in simulation tracheas. We then evaluated EAM in a large animal model (Ovis aries, n = 5), comparing tracheal dimensions obtained with EAM to measurements obtained via 3-D fluoroscopic reconstruction. The animal then underwent resection of the measured segment, and direct measurement of this segment was performed and compared to radiographic measurements and those obtained using EAM.
  
  
  RESULTS
  The simulation tracheas had a direct measurement of 13.6, 18.5, and 24.2 mm in diameter. The mean difference of diameter in simulation tracheas between direct measurements and measurements obtained using EAM was 0.70 ± 0.57 mm. The excised ovine tracheas had an average diameter of 18.54 ± 0.68 mm. The percent difference in diameter obtained from EAM and from 3-D fluoroscopic reconstruction when compared to measurement of the excised tracheal segment was 4.98 ± 2.43% and 10.74 ± 4.07% respectively. Comparison of these three measurements (EAM, measurement of resected trachea, 3-D fluoroscopic reconstruction) with repeated measures ANOVA demonstrated no statistical significance.
  
  
  CONCLUSIONS
  Endoscopic airway measurement (EAM) provides equivalent measurements of the airway with the improved versatility of measuring non-circular and multi-level dimensions. Using optical bronchoscopic instruments and open-source image-processing software, our data supports preclinical and clinical translation of an accessible technique to provide objective quantification of airway diameter.
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA; Department of Pediatric Surgery, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
authors.forename: Victoria K
authors.initials: VK
authors.lastname: Pepper
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Ohio State University, 915 Olentangy River Rd # 4000, Columbus, OH, 43212, USA; Department of Pediatric Otolaryngology Head and Neck Surgery, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Francom
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA.
authors.forename: Cameron A
authors.initials: CA
authors.lastname: Best
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA; Department of Surgery, The Ohio State University, Wexner Medical Center, 395 W. 12th Ave., Suite 670, Columbus, OH, 43210, USA.
authors.forename: Ekene
authors.initials: E
authors.lastname: Onwuka
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA; Department of Surgery, The Ohio State University, Wexner Medical Center, 395 W. 12th Ave., Suite 670, Columbus, OH, 43210, USA.
authors.forename: Nakesha
authors.initials: N
authors.lastname: King
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Heuer
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Mahler
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Ohio State University, 915 Olentangy River Rd # 4000, Columbus, OH, 43212, USA; Department of Pediatric Otolaryngology Head and Neck Surgery, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Grischkan
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA; Department of Pediatric Surgery, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Breuer
authors.affiliation: Tissue Engineering and Surgical Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Suite WB4154, Columbus, OH, 43205, USA; Department of Otolaryngology Head and Neck Surgery, The Ohio State University, 915 Olentangy River Rd # 4000, Columbus, OH, 43212, USA; Department of Pediatric Otolaryngology Head and Neck Surgery, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA. Electronic address: tendy.chiang@nationwidechildrens.org.
authors.forename: Tendy
authors.initials: T
authors.lastname: Chiang
mesh_terms: D000818:Animals; D004724:Endoscopy; D005471:Fluoroscopy; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D023421:Models, Animal; D008954:Models, Biological; D012756:Sheep; D014132:Trachea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*
keywords: Airway management; Airway reconstruction; Airway stenosis; Image processing; Quantitative endoscopy