CT metrics of airway disease and emphysema in severe COPD

Chest. 2009 Aug;136(2):396-404. doi: 10.1378/chest.08-2858. Epub 2009 May 1.


Background: CT scan measures of emphysema and airway disease have been correlated with lung function in cohorts of subjects with a range of COPD severity. The contribution of CT scan-assessed airway disease to objective measures of lung function and respiratory symptoms such as dyspnea in severe emphysema is less clear.

Methods: Using data from 338 subjects in the National Emphysema Treatment Trial (NETT) Genetics Ancillary Study, densitometric measures of emphysema using a threshold of -950 Hounsfield units (%LAA-950) and airway wall phenotypes of the wall thickness (WT) and the square root of wall area (SRWA) of a 10-mm luminal perimeter airway were calculated for each subject. Linear regression analysis was performed for outcome variables FEV(1) and percent predicted value of FEV(1) with CT scan measures of emphysema and airway disease.

Results: In univariate analysis, there were significant negative correlations between %LAA-950 and both the WT (r = -0.28, p = 0.0001) and SRWA (r = -0.19, p = 0.0008). Airway wall thickness was weakly but significantly correlated with postbronchodilator FEV(1)% predicted (R = -0.12, p = 0.02). Multivariate analysis showed significant associations between either WT or SRWA (beta = -5.2, p = 0.009; beta = -2.6, p = 0.008, respectively) and %LAA-950 (beta = -10.6, p = 0.03) with the postbronchodilator FEV(1)% predicted. Male subjects exhibited significantly thicker airway wall phenotypes (p = 0.007 for WT and p = 0.0006 for SRWA).

Conclusions: Airway disease and emphysema detected by CT scanning are inversely related in patients with severe COPD. Airway wall phenotypes were influenced by gender and associated with lung function in subjects with severe emphysema.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Airway Obstruction / diagnostic imaging
  • Airway Obstruction / physiopathology
  • Analysis of Variance
  • Cohort Studies
  • Dyspnea / diagnostic imaging*
  • Dyspnea / physiopathology
  • Female
  • Forced Expiratory Volume
  • Humans
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Predictive Value of Tests
  • Probability
  • Pulmonary Disease, Chronic Obstructive / diagnostic imaging*
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Pulmonary Emphysema / diagnostic imaging*
  • Pulmonary Emphysema / physiopathology
  • Pulmonary Ventilation / physiology*
  • Respiratory Function Tests
  • Risk Assessment
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Tomography, X-Ray Computed*
  • Total Lung Capacity / physiology