[Imaging of pneumonia].

In patients with suspected pneumonia, chest radiography and CT play an important role in making the differential diagnosis and evaluating disease severity and progress. The radiologic patterns of both community-acquired and opportunistic pneumonias were reviewed and compared with those of non-infectious lung diseases. The important findings in the diagnosis of pneumonias were as follows: 1) the relationship between the extent of consolidation and segment or lobe; 2) homogeneity or heterogeneity of opacity; 3) presence of thickening of bronchi and bronchioli; centrilobular, acinar, lobular, and segmental opacities; air bronchogram; tree-inbud appearance, and mosaic perfusion; and 4) size and distribution of nodules.