Relationship between emphysema quantification and COPD severity

Abstract

© 2014, Medical Association of Thailand. All rights reserved. Objective: To determine the association between emphysema extent from high-resolution computed tomography (HRCT) and the physiological derangement in patients with chronic obstructive pulmonary disease (COPD). Material and Method: A cross-sectional study was undertaken to quantify the emphysema severity in 23 COPD patients by automated HRCT scoring techniques. Correlation with phenotypic characters in term of exercise capacity [Modified Medical Research Council (mMRC) dyspnea scale, and 6-minute walk distance (6MWD)], pulmonary function testing [spirometry (forced expiratory volume in 1 second, FEV<inf>1</inf> and forced vital capacity, FVC), and diffusing capacity (DLCO)], were then assessed. Results: Nineteen patients were male and four were female, the mean age was 73±8 years, with the mean FEV<inf>1</inf>%predicted of 67.8±25.4. Percentage of inspiratory emphysematous lung volume (%ELVi) had significant negative correlation with %FEV<inf>1</inf>/FVC (r = -0.50, p = 0.016) and DLCO (r = 0.58, p = 0.011). Percentage of expiratory emphysematous lung volumes (%ELVe) also had the same correlation with %FEV<inf>1</inf>/FVC (r = -0.58, p = 0.004) and DLCO (r = 0.48, p = 0.042). In addition, %ELVe also had significant negative correlation with 6MWD (r = 0.50, p = 0.016), but had significant positive correlation with mMRC scale (r = 0.53, p = 0.01). Conclusion: Severity of emphysema assessed by HRCT was well correlated with pulmonary function test results and exercise capacity. It can be used as one aspect of phenotypic characters in patients with COPD, for designing personalize management plan.