Figure 1

Axial inspiratory CT scans at the level of right inferior pulmonary vein, from three 54 year old females, representing typical patterns; Left panel: healthy never-smoker; Middle panel: smoker (note subtle uniform diffuse increased opacity which makes vessels more visible and mild interlobular septal thickening, especially in middle lobe; Right panel: COPD (note diffusely distributed centrilobular emphysema, more in central part of scans, with radiolucency and irregular vascular pattern).