Evaluation of computed tomography in the detection of pulmonary metastases: a prospective study.

Conventional linear x-ray tomography is often used to search for pulmonary metastases but tends to underestimate extent of disease when compared with operative findings. In a prospective study, operative findings were correlated with computed axial tomography and conventional linear tomography performed on 25 patients with a history of extrathoracic malignancy and pulmonary nodules. Computed tomography detected 69 nodules of which 31 proved to be metastases. Conventional linear tomography detected 38 nodules of which 25 were metastases. Of the 54 resected nodules measuring greater than 3 mm, computed tomography detected 42; whereas conventional tomography detected 32. Only six of the 31 additional nodules (20%) detected by computed tomography and not by conventional tomography proved to be metastases. These results suggest that computed tomography is more sensitive than conventional tomography in detecting small pulmonary nodules; however, there is diminished specificity in identifying metastatic nodules.