title: Serial change in airway lumen and wall thickness at thin-section CT in asymptomatic subjects.
abstract: OBJECTIVE
  To retrospectively analyze serial changes in airway lumen and wall thickness (WT) at multi-detector row computed tomography (CT) in asymptomatic subjects.
  
  
  METHODS
  Institutional review board did not require its approval or informed patient consent. Airway dimensions were analyzed in 52 patients (30 men and 22 women) without known cardiopulmonary disease. Contiguous 2-mm CT sections were obtained after reconstruction, extending from origin of right posterior basal segmental bronchi to posterior subsegmental bronchi. Following parameters were determined with semiautomatic image-processing program: luminal area (LA), total airway area (TA), short axis of lumen (LSD), and short axis of total airway (TSD). In airways in which adjacent vessel or branching of small bronchus abutted boundary of airway, extrapolated line was traced by one radiologist. Airway wall area (WA) was calculated as TA - LA, and WT was calculated as (TSD - LSD)/2. Relative WA (WA% = [WA/TA] . 100) and ratio of airway WT to total diameter (D) (WT/D = WT/TSD) were calculated. Linear regression analysis and Spearman rank correlation were used to evaluate relationship between airway parameters (LA, WA%, and WT/D ratio) and distance from origin of segmental bronchi.
  
  
  RESULTS
  LA decreased as CT proceeded from hilum to periphery (r = -0.765, P < .001). In 308 (32.7%) of 943 bronchi, however, LA increased as CT proceeded from hilum to periphery. LA increased by 10% or more in 101 (10.7%) of 943 bronchi. Mean changes in WA% and WT/D ratio between two contiguous sections were 0.66 +/- 5.05 (standard deviation) and 0.003 +/- 0.024, respectively. WA% changed by more than 5% between two contiguous sections in 274 (29.0%) of 943 bronchi. WT/D ratio changed by more than 0.02 between two contiguous sections in 338 (35.8%) of 943 bronchi.
  
  
  CONCLUSIONS
  Variation of airway lumen and WT is found in asymptomatic subjects without known cardiopulmonary disease.
authors.affiliation: Department of Diagnostic Radiology, Fujisawa City Hospital, Fujisawa City, Kanagawa, Japan. shinma@d9.dion.ne.jp
authors.forename: Shin
authors.initials: S
authors.lastname: Matsuoka
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kurihara
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nakajima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Niimi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ashida
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kaneoya
mesh_terms: D000328:Adult; D001995:Bronchography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*