Computed tomographic measurements of airway dimensions and emphysema in smokers - Correlation with lung function

Chronic obstructive pulmonary disease (COPD) is characterized by the presen ce of airflow obstruction caused by emphysema or airway narrowing, or both. Low attenuation areas (LAA) on computed tomography (CT) have been shown to represent macroscopic or microscopic emphysema, or both. However CT has no t been used to quantify the airway abnormalities in smokers with or without airflow obstruction. In this study, we used CT to evaluate both emphysema and airway wall thickening in 114 smokers. The CT measurements revealed tha t a decreased FEV1 (%predicted) is associated with an increase of airway wa ll area and an increase of emphysema. Although both airway wall thickening and emphysema (LAA) correlated with measurements of lung function, stepwise multiple regression analysis showed that the combination of airway and emp hysema measurements improved the estimate of pulmonary function test abnorm alities. We conclude that both CT measurements of airway dimensions and emp hysema are useful and complementary in the evaluation of the lung of smoker s.