CT of pulmonary metastases with pathological correlation.

CT, including high-resolution CT, has become an essential means of imaging to evaluate pulmonary metastases. The underlying pathological processes of pulmonary metastases can be observed well on CT images, but they are not always specific. Several important CT features correlate with histopathological findings: (1) margin of nodule; (2) hemorrhage accompanying a metastatic nodule; (3) calcification; (4) cavitation; (5) sterilized metastasis; (6) small metastatic nodules in the lobules; (7) lymphangitic carcinomatosis; (8) tumor emboli; and (9) pleural metastases. For reasonable use of CT in pulmonary metastases, these various CT manifestations and their limitations must be understood.