Quantitative computed tomography analysis of emphysema severity and distribution in chronic obstructive lung disease, correlation with clinical findings

Abstract

Introduction: This study aimed to evaluate the correlation between different densitometric parameters on chest computed tomography (CT) and pulmonary function tests (PFT) of patients with emphysema-predominant chronic obstructive pulmonary disease (COPD). Materials and Methods: A retrospective evaluation was made of 56 patients with COPD. The lungs were segmented into nine sections. Normal and emphysematous parenchyma were measured using low attenuation area percentage (%LAA), percentile density (PD), and mean lung density (MLD) parameters. The effects of emphysema distribution on PFT were evaluated using %LAA, PD, MLD, kurtosis and skewness methods. Results: Fifty-six patients, all diagnosed with COPD, were evaluated. The %LAA-910 method showed significant correlation with forced expiratory volume in one second (FEV1) compared to other densitometric parameters (p=<0.001, r=-0.556). Other densitometric parameters differed between segments in terms of sensitivity for FEV1. It was determined that right lung mid-zone segment involvement affected FEV1 more than other segments when the %LAA -910 method was used (p=<0.001, r=-0.569). %LAA -950 had the largest area under the curve in ROC curve analysis and was determined to have 2.2% diagnostic property for predicting Global Initiative for Obstructive Lung Disease (GOLD) AB-CD staging (sensitivity 81%, specificity 74%). Conclusion: Quantitative analysis is an objective method for determining the distribution and severity of emphysema. There was a significant correlation between densitometry and PFT values. Quantitative analysis may be considered suitable for use in evaluating the severity of emphysema and predicting the clinical findings of patients.