Pulmonary metastatic nodules: CT-pathologic correlation.

To elucidate the characteristics of pulmonary metastatic nodules on high-resolution computed tomographic (HRCT) scans, a correlative computed tomographic (CT)-pathologic study was performed with five human lungs after autopsy. The relationship of metastatic nodules to pulmonary vessels was studied with HRCT scans, radiographs of the specimen, and stereomicroscopic study in 264 nodules 0.6-9.0 mm in diameter. On radiographs and stereomicroscopic images, 190 small nodules (less than 3 mm in diameter) were in contact with the pulmonary lobule on the central bronchovascular bundles (n = 33 [17.4%]), located between the central bronchovascular bundle and the perilobular structure (n = 127 [66.8%]), or attached to perilobular structures (n = 30 [15.8%]). On HRCT scans, 21 small nodules (11.1%) were located on the central bronchovascular bundle; 130 small nodules (68.4%), between the central bronchovascular bundle and the perilobular structure; and 39 small nodules (20.5%), on the perilobular structure. On radiographs and stereomicroscopic images, 43 of 74 large nodules (greater than 3 mm in diameter) (58%) compressed both bronchovascular bundles and perilobular structures. The central bronchovascular bundle was invaded in only 13 large nodules (18%).