Segmental bronchi collapsibility: computed tomography-based quantification in patients with chronic obstructive pulmonary disease and correlation with emphysema phenotype, corresponding lung volume changes and clinical parameters

Abstract

Background: Global pulmonary function tests lack region specific differentiation that might influence therapy in severe chronic obstructive pulmonary disease (COPD) patients. Therefore, the aim of this work was to assess the degree of expiratory 3 rd generation bronchial lumen collapsibility in patients with severe COPD using chest-computed tomography (CT), to evaluate emphysema-phenotype, lobar volumes and correlate results with pulmonary function tests.Methods: Thin-slice chest-CTs acquired at end-inspiration & end-expiration in 42 COPD GOLD IV patients (19 females, median-age: 65.9 y) from November 2011 to July 2014 were re-evaluated. The crosssectional area of all segmental bronchi was measured 5 mm below the bronchial origin in both examinations.Lung lobes were semi-automatically segmented, volumes calculated at end-inspiratory and end-expiratory phase and visually defined emphysema-phenotypes defined. Results of CT densitometry were compared with lung functional tests including forced expiratory volume at 1 s (FEV 1 ), total lung capacity (TLC), vital capacity (VC), residual volume (RV), diffusion capacity parameters and the maximal expiratory flow rates (MEFs).Results: Mean expiratory bronchial collapse was 31%, stronger in lobes with homogenous (38.5%) vs.heterogeneous emphysema-phenotype (27.8%, P=0.014). The mean lobar expiratory volume reduction was comparable in both emphysema-phenotypes (volume reduction 18.6%±8.3% in homogenous vs.17.6%±16.5% in heterogeneous phenotype). The degree of bronchial lumen collapsibility, did not correlate with expiratory volume reduction. MEF 25 correlated weakly with 3 rd generation airway collapsibility (r=0.339, P=0.03). All patients showed a concentric expiratory reduction of bronchial cross-sectional area.Conclusions: Changes in collapsibility of 3 rd generation bronchi in COPD grade IV patients is significantly lower than that in the trachea and the main bronchi. Collapsibility did not correlate with the reduction in lung volume but was significantly higher in lobes with homogeneous vs. heterogeneous emphysema phenotype. Changes in the 3 rd generation bronchial calibres between inspiration and expiration are not predictive for the degree of small airway collapsibility and related airflow limitation.

Identification of COPD From Multi-View Snapshots of 3D Lung Airway Tree via Deep CNN

“…McDonough et al [44] found that small conducting airways (<2.0 mm) in COPD become narrow and disappear before the onset of emphysema. Previous reports have asserted that these abnormalities in small airways will be reflected in large-and intermediate-sized airways [45]- [47]. A reduced tracheal section, total airway count on CT and airway branch variation have been proposed as the independent and innate risk factor of COPD [17], [19], [20], [43].…”

Long-term observational study on the impact of GLP-1R agonists on lung function in diabetic patients

“…The treatment with GLP-1R agonists was also effective on secondary outcomes, as it significantly improved FVC, MEF 75 and MEF 50 , but not MEF 25 . The lack of effectiveness on MEF 25 , a variable that measures the flow rates at low lung volume providing the physiological assessment of small airways function [31,32], can be explained by considering that in humans the GLP-1R is expressed on the ASM of medium airways (segmental bronchi) but not in small airways (bronchioles) [30]. Interestingly, in the control cohort, the treatment with metformin alone not only elicited a numerical improvement of FEV 1 , but also significantly improved FVC.…”

Prediction of response to endobronchial coiling based on morphologic emphysema characterization of the lung lobe to be treated and the ipsilateral non-treated lobe as well as on functional computed tomography-data: correlation with clinical and pulmonary function

“…For this purpose, different morphologic and functional methods have been proposed, which are mostly based on the differentiation of homogeneous and heterogeneous emphysema phenotypes (16,18,19). While this differentiation can be performed visually on high-resolution CT images of the chest, quantification of lung parenchymal density may be more accurate, and calculation of the distribution of emphysema equivalent areas has become practicable based on the so-called "cluster analysis" (20). In order to understand which impact the interplay of different lobar phenotypes could potentially have in a patient, we performed lobar-based phenotype analysis of the targeted lobe, and also of the nontargeted ipsilateral and contralateral lung lobes.…”