The CT manifestations of emphysema are as follows: 1) hyperinflation of emphysema with CT manifestation of hypointense shadow; 2) decreased CT value with thinning and sparse surrounding vessels; 3) thickening and enlargement of pulmonary hilar vessels. There are four types of emphysema according to their manifestations, including lobar-centered, central, paralobular septal, and scar emphysema. Total lobar emphysema CT shows a large range of 5B hypointense areas with irregular morphology, thinning and deformation of surrounding blood vessels, mostly in the middle and lower lobes; central lobar emphysema CT shows scattered patches and masses of 5B hypointense areas with a size of about 2-10 mm; parafollicular septal emphysema CT shows a limited distribution and visible pulmonary blisters; scar emphysema is distributed around scars. Such as around tuberculosis foci as well as pneumoconiosis fibrosis foci, alveolar dilatation as well as fibrosis destruction, branched expansion destruction, and honeycomb foci next to the rupture; pulmonary emphysema with pulmonary blister diameter >1cm or more, prone to spontaneous pneumothorax.