Airway morphology and inspiratory flow features in the early stages of Chronic Obstructive Pulmonary Disease. (June 2019)

• Record Type: Journal Article
• Authors: Van de Moortele, Tristan; Goerke, Ute; Wendt, Chris H.; Coletti, Filippo
• Is Part Of: Clinical biomechanics. Volume 66(2019)
• Page Start: 60
• Page End: 65
• Publication Date: 2019-06
• Subjects: Chronic Obstructive Pulmonary Disease -- Computed tomography -- Magnetic resonance imaging -- Airway morphology -- Respiratory fluid dynamics; Biomechanics -- Periodicals; Osteopathic medicine -- Periodicals; Biomechanics -- Periodicals; Osteopathic Medicine -- Periodicals; 612.76
• DOI: 10.1016/j.clinbiomech.2017.11.005
• Languages: English
• ISSNs: 0268-0033

Abstract

Abstract: Background: Chronic Obstructive Pulmonary Disease (COPD) is among the leading causes of death worldwide. Inhaled pollutants are the prime risk factor, but the pathogenesis and progression of the diseased is poorly understood. Most studies on the disease onset and trajectory have focused on genetic and molecular biomarkers. Here we investigate the role of the airway anatomy and the consequent respiratory fluid mechanics on the development of COPD. Methods: We segmented CT scans from a five-year longitudinal study in three groups of smokers (18 subjects each) having: (i) minimal/mild obstruction at baseline with declining lung function at year five; (ii) minimal/mild obstruction at baseline with stable function, and (iii) normal and stable lung function over the five year period. We reconstructed the bronchial trees up to the 7th generation, and for one subject in each group we performed MRI velocimetry in 3D printed models. Findings: The subjects with airflow obstruction at baseline have smaller airway diameters, smaller child-to-parent diameter ratios, larger length-to-diameter ratios, and smaller fractal dimensions. The differences are more significant for subjects that develop severe decline in pulmonary function. The secondary flows that characterize lateral dispersion along the airways are found to be less intense in the subjects with airflow obstruction. Interpretation: These results indicate that morphology of the conducting airways and inspiratory flow features are correlated with the status and progression of COPD already at an early stage of the disease. This suggests that imaging-based biomarkers may allow a pre-symptomatic diagnosis of disease progression. Highlights: We investigate structure and function in Chronic Obstructive Pulmonary Disease. We study airway morphology by segmenting and analyzing high-resolution CT scans. We perform in vitro inhalation experiments in 3D printed models of subject airways. We measure detailed inspiratory flow field by MRI velocimetry. Airway morphology and inspiratory flow appear correlated with disease progression.