title: Airway wall thickness assessed using computed tomography and optical coherence tomography.
abstract: BACKGROUND
  Computed tomography (CT) has been shown to reliably measure the airway wall dimensions of medium to large airways. Optical coherence tomography (OCT) is a promising new micron-scale resolution imaging technique that can image small airways 2 mm in diameter or less.
  
  
  OBJECTIVE
  To correlate OCT measurements of airway dimensions with measurements assessed using CT scans and lung function.
  
  
  METHODS
  Forty-four current and former smokers received spirometry, CT scans, and OCT imaging at the time of bronchoscopy. Specific bronchial segments were identified and measured using the OCT images and three-dimensional reconstructions of the bronchial tree using CT.
  
  
  RESULTS
  There was a strong correlation between CT and OCT measurements of lumen and wall area (r = 0.84, P < 0.001, and r = 0.89, P < 0.001, respectively). Compared with CT, OCT measurements were lower for both lumen and wall area by 31 and 66%, respectively. The correlation between FEV(1)% predicted and CT and OCT measured wall area (as percentage of the total area) of fifth-generation airways was very strong (r = -0.79, r = -0.75), but the slope of the relationship was much steeper using OCT than using CT (y = -0.33x + 82, y = -0.1x + 78), indicating greater sensitivity of OCT in detecting changes in wall measurements that relate to FEV(1).
  
  
  CONCLUSIONS
  OCT can be used to measure airway wall dimensions. OCT may be more sensitive at detecting small airway wall changes that lead to FEV(1) changes in individuals with obstructive airway disease.
authors.affiliation: Department of Radiology, Vancouver General Hospital, 855 West 12th Avenue, Room 3350 JPN, Vancouver, BC, Canada. harvey.coxson@vch.ca
authors.forename: Harvey O
authors.initials: HO
authors.lastname: Coxson
authors.forename: Brendan
authors.initials: B
authors.lastname: Quiney
authors.forename: Don D
authors.initials: DD
authors.lastname: Sin
authors.forename: Li
authors.initials: L
authors.lastname: Xing
authors.forename: Annette M
authors.initials: AM
authors.lastname: McWilliams
authors.forename: John R
authors.initials: JR
authors.lastname: Mayo
authors.forename: Stephen
authors.initials: S
authors.lastname: Lam
mesh_terms: D000368:Aged; D001980:Bronchi / Q000473:pathology* / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence; D014057:Tomography, X-Ray Computed