title: The relationship between lung function impairment and quantitative computed tomography in chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  To determine the relationship between lung function impairment and quantitative computed tomography (CT) measurements of air trapping and emphysema in a population of current and former heavy smokers with and without airflow limitation.
  
  
  METHODS
  In 248 subjects (50 normal smokers; 50 mild obstruction; 50 moderate obstruction; 50 severe obstruction; 48 very severe obstruction) CT emphysema and CT air trapping were quantified on paired inspiratory and end-expiratory CT examinations using several available quantification methods. CT measurements were related to lung function (FEV(1), FEV(1)/FVC, RV/TLC, Kco) by univariate and multivariate linear regression analysis.
  
  
  RESULTS
  Quantitative CT measurements of emphysema and air trapping were strongly correlated to airflow limitation (univariate r-squared up to 0.72, p < 0.001). In multivariate analysis, the combination of CT emphysema and CT air trapping explained 68-83% of the variability in airflow limitation in subjects covering the total range of airflow limitation (p < 0.001).
  
  
  CONCLUSIONS
  The combination of quantitative CT air trapping and emphysema measurements is strongly associated with lung function impairment in current and former heavy smokers with a wide range of airflow limitation.
authors.affiliation: Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3508GA, Postbus 85500, Utrecht, The Netherlands. o.m.mets@umcutrecht.nl
authors.forename: O M
authors.initials: OM
authors.lastname: Mets
authors.forename: K
authors.initials: K
authors.lastname: Murphy
authors.forename: P
authors.initials: P
authors.lastname: Zanen
authors.forename: H A
authors.initials: HA
authors.lastname: Gietema
authors.forename: J W
authors.initials: JW
authors.lastname: Lammers
authors.forename: B
authors.initials: B
authors.lastname: van Ginneken
authors.forename: M
authors.initials: M
authors.lastname: Prokop
authors.forename: P A
authors.initials: PA
authors.lastname: de Jong
mesh_terms: D000704:Analysis of Variance; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D033162:Incidental Findings; D016014:Linear Models; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008448:Maximal Expiratory Flow Rate; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects / Q000503:physiopathology; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity