Open Access 01-01-2012 | Computed Tomography
The relationship between lung function impairment and quantitative computed tomography in chronic obstructive pulmonary disease
Published in: European Radiology | Issue 1/2012
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Objectives
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 (FEV1, FEV1/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.
Key Points
• CT helps to automatically assess lung disease in heavy smokers
• CT quantitatively measures emphysema and small airways disease in heavy smokers
• CT air trapping and CT emphysema are associated with lung function impairment