Fig. 4

A 65-year-old male, COPD patient with FEV₁% 38.5 and %FEV₁ 16.3, which meets the criteria of GOLD 4, COPD Severe group. Blue rectangles in Fig. 3 (d) represent bilateral ROIs. VF-DXR images in (a) tidal inspiratory, (b) tidal expiratory, (c) forced inspiratory, and d forced expiratory phase. Blue rectangles represent bilateral ROIs. (e) The graph shows the temporal change between LMV in the right lung and the number of frames. The frame rate is set to 5 frames/s (Video 2 in the Supplemental material). COPD Chronic obstructive pulmonary disease, FEV₁% Forced expiratory volume percent in one second divided by forced vital capacity, %FEV₁ Percent predicted forced expiratory volume in one second, GOLD Global initiative for chronic obstructive lung disease, LMV Lung motion velocity, ROI region of interest, VF-DXR Vector-field dynamic x-ray