Quantitative computed tomography imaging in asthma and chronic obstructive pulmonary disease.

Abstract

Background: Severe refractory asthma (SRA) and chronic obstructive pulmonary disease (COPD) are characterized by persistent airflow limitation and irreversible changes in morphology of the bronchial tree. Objectives: The primary aim of this study was to evaluate the intensity of remodelling of bronchi in patients with SRA and COPD using quantitative computed tomography (QCT). The secondary aim was to establish the relationship between the remodelling and airflow limitation. Methods and Materials: Enrollment of patients into the study: 10 patients with SRA, 12 patients with COPD and 11 healthy subjects (HS) with no respiratory disease and no history of smoking. All subjects had chest computed tomography performed at full inspiration and breath-holds (128-slice non-contrast CT, with low dose reconstruction algorithm) and subsequently pulmonary function test. Quantitative reconstructions of the CT-data was performed on dedicated workstation with syngo.via Pulmo3D software. The measurements of wall thickness (WT) and lumen area (LA) were performed from third to ninth generation of the bronchi in right lower lobe. Results of QCT were intercorrelated with FEV1, FVC and FEV1/FVC%. Results: There was significant difference in the wall thickness between SRA, COPD and HS patients. WT in 3rd to 8th generations was significantly intensified in SRA group compared to COPD and HS groups (p<0,05). There was significant correlation between WT (5th to 9th generation) and FEV1 (r=0,13-0,24, p<0,05). Conclusion: Airway remodelling is more pronounced in patients with SRA. There is close relationship between airflow limitation and airway remodelling.