title: Intrathoracic tracheal volume and collapsibility on inspiratory and end-expiratory ct scans correlations with lung volume and pulmonary function in 85 smokers.
abstract: OBJECTIVE
  To evaluate the correlations of tracheal volume and collapsibility on inspiratory and end-expiratory computed tomography (CT) with lung volume and with lung function in smokers.
  
  
  METHODS
  The institutional review board approved this study at each institution. 85 smokers (mean age 68, range 45-87 years; 40 females and 45 males) underwent pulmonary function tests and chest CT at full inspiration and end-expiration. On both scans, intrathoracic tracheal volume and lung volume were measured. Collapsibility of the trachea and the lung was expressed as expiratory/inspiratory (E/I) ratios of these volumes. Correlations of the tracheal measurements with the lung measurements and with lung function were evaluated by the linear regression analysis.
  
  
  RESULTS
  Tracheal volume showed moderate or strong, positive correlations with lung volume on both inspiratory (r = 0.661, P < .0001) and end-expiratory (r = 0.749, P < .0001) scans. The E/I ratio of tracheal volume showed a strong, positive correlation with the E/I ratio of lung volume (r = 0.711, P < .0001). A weak, negative correlation was found between the E/I ratio of tracheal volume and the ratio of forced expiratory volume in the first second to forced vital capacity (r = -0.436, P < .0001). Also, a weak, positive correlation was observed between the E/I ratio of tracheal volume and the ratio of residual volume to total lung capacity (r = 0.253, P = .02).
  
  
  CONCLUSIONS
  Tracheal volume and collapsibility, measured by inspiratory and end-expiratory CT scans, is related to lung volume and collapsibility. The highly collapsed trachea on end-expiratory CT does not indicate more severe airflow limitation or air-trapping in smokers.
authors.affiliation: Center for Pulmonary Functional Imaging, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Yamashiro
authors.forename: Raúl
authors.initials: R
authors.lastname: San José Estépar
authors.forename: Shin
authors.initials: S
authors.lastname: Matsuoka
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Bartholmai
authors.forename: James C
authors.initials: JC
authors.lastname: Ross
authors.forename: Alejandro
authors.initials: A
authors.lastname: Diaz
authors.forename: Sadayuki
authors.initials: S
authors.lastname: Murayama
authors.forename: Edwin K
authors.initials: EK
authors.lastname: Silverman
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatabu
authors.forename: George R
authors.initials: GR
authors.lastname: Washko
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D015656:Respiratory Mechanics; D012907:Smoking / Q000503:physiopathology*; D013223:Statistics as Topic; D013990:Tidal Volume; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000000981:diagnostic imaging* / Q000503:physiopathology*