Comparison of endobronchial ultrasound and high resolution computed tomography as tools for airway wall imaging in asthma and chronic obstructive pulmonary disease

Abstract

IntroductionAirway remodeling in asthma and chronic obstructive pulmonary disease (COPD) results in bronchial wall thickening. Bronchial wall thickness (BWT) can be assessed in high-resolution computed tomography (HRCT) and endobronchial ultrasound (EBUS). AimsTo compare BWT measured by EBUS and HRCT in patients with mild-to-moderate asthma and COPD, and to evaluate the relationship between the BWT and pulmonary function. MethodsThe study included patients with mild-to-moderate asthma (n = 24), COPD (n = 36) and controls (n = 12). Bronchoscopy with EBUS (radial probe) and HRCT were performed to measure the BWT in the segmental bronchus. ResultsGood overall agreement between EBUS and HRCT measurements of BWT was demonstrated. Median HRCT-BWT did not reveal any significant differences between individuals with asthma and COPD, and control subjects: 1.56 (1.27–1.70) mm, 1.62 (1.45–1.90) mm, and 1.63 (1.41–1.77) mm, respectively (p = 0.315). In contrast, median BWT measured by EBUS was significantly higher in asthma and COPD groups when compared to controls: 1.20 (1.02–1.41) mm, 1.19 (1.10–1.48) mm, and 0.99 (0.90–1.08) mm, respectively (p = 0.006). There were no differences in BWT in mild-to-moderate asthma and COPD or significant correlations between BWT and the results of pulmonary function tests. ConclusionsThe use of EBUS to assess BWT in asthma and COPD is feasible and it shows good compatibility with HRCT. A tendency towards lower BWT values in EBUS when compared to HRCT was observed. The finding that EBUS measurements demonstrated the differences between BWT in patients with obstructive lung diseases and controls, may suggest that EBUS is a more sensitive method to study the BWT than HRCT.