title: Airway distensibility by HRCT in asthmatics and COPD with comparable airway obstruction.
abstract: BACKGROUND
  Decreased airway distensibility (AD) in response to deep inspirations, as assessed by HRCT, has been associated with the severity of asthma and COPD.
  
  
  OBJECTIVE
  The current study was designed to compare the magnitude of AD by HRCT in individuals with asthma and COPD with comparable degrees of bronchial obstruction, and to explore factors that may influence it.
  
  
  RESULTS
  We enrolled a total of 12 asthmatics (M/F:7/5) and 8 COPD (7/1) with comparable degree of bronchial obstruction (FEV1% predicted mean ± SEM: 69.1 ± 5.2% and 61.2 ± 5.0%, respectively; p = 0.31). Each subject underwent chest HRCT at FRC and at TLC. A total of 701 airways (range 20 to 38 airway per subject; 2.0 to 23.1 mm in diameter) were analyzed. AD did not differ between asthmatics and COPD (mean ± SEM: 14 ± 3.5% and 17 ± 4.3%, respectively; p = 0.58). In asthmatics, AD was significantly associated with FEV1% predicted (r(2) = 0.45, p = 0.018). We found a significant correlation between the change in lung volume and the change in AD by HRCT (r(2) = 0.64, p = 0.002). In COPD, we found significant correlations between AD and the RV% predicted (r(2) = 0.51, p = 0.046) and the RV/TLC (r(2) = 0.68, p = 0.01).
  
  
  CONCLUSIONS
  AD was primarily affected by the dynamic ability to change lung volumes in asthmatics, and by static lung volumes in COPD.
authors.affiliation: 1Dipartimento di Biomedicina e Medicina Specialistica, Sezione di Pneumologia, University of Palermo , Palermo , Italy.
authors.forename: Alida
authors.initials: A
authors.lastname: Benfante
authors.forename: Maria
authors.initials: M
authors.lastname: Bellia
authors.forename: Nicola
authors.initials: N
authors.lastname: Scichilone
authors.forename: Fabio
authors.initials: F
authors.lastname: Cannizzaro
authors.forename: Massimo
authors.initials: M
authors.lastname: Midiri
authors.forename: Robert
authors.initials: R
authors.lastname: Brown
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Bellia
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000000981:diagnostic imaging*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging*; D013147:Spirometry; D014797:Vital Capacity