Dynamic Chest Radiography Measured Postretoanterior Total Lung Area Correlates with FEV1 in Healthy Volunteers and COPD Patients

Introduction: Dynamic chest radiography (DCR) is a novel technology that allows real time observation of respiratory kinetics and measurement of lung volumes during different parts of the respiratory cycle. Changes in lung area during respiration have been shown to correlate with vital capacity and total lung capacity.1 Aim: To correlate measurements of lung area during tidal and deep breathing on posteroanterior (PA) DCR images with spirometry measurements made on a group of healthy volunteers and COPD patients. Methods: Data from 21 DCR image sequences obtained during tidal and deep breathing from 13 patients (5 healthy volunteers, 8 COPD patients) were analysed. Standard protocols were used to measure lung area during maximum inspiration during both tidal and deep breathing. Model based partial coefficients, correcting for the effect of the type of breathing (deep or tidal) were evaluated. Pearson’s correlation coefficients were investigated over the average of the type of breathing. Results: On analysis of data averaged over the type of breathing, correlations between total lung area at maximal inspiration and both FEV1 and FEV1 % predicted were significant (p Conclusion: Relatively simple analysis of DCR image sequences offers the opportunity to obtain lung function data at the same time as obtaining the anatomical information provided by a chest x-ray. Reference: 1. Okhura N et al Evaluation of Pulmonary Function Using Dynamic Chest Radiographs: The Change Rate in Lung Area Due to Respiratory Motion Reflects Air Trapping in COPD, American Journal of Respiratory and Critical Care Medicine 2018;197:A3893