Solitary pulmonary opacities: plain tomography

New or enlarging solitary pulmonary opacities in 502 patients were evaluated with a plain tomographic procedure. Repeat chest radiographs in 64 patients and tomograms in 115 patients showed that the opacities were not nodules but were due to pneumonitis, rib lesions, thickened pleura, or another benign finding. Tomography demonstrated 85 of the 323 nodules to be calcified granulomas. The shape of the 238 uncalcified nodules was classified as benign, malignant, or indeterminate. None of the 38 nodules classified as benign proved to be malignant during 2 years of follow-up. Of the 33 nodules with a malignant shape, 31 proved to be malignant at operation or clinical follow-up. Among the 167 nodules characterized as indeterminate, 128 were benign and 39 were malignant on follow-up. In this series, the plain tomographic procedure, including fluoroscopy and repeat chest radiography, allowed an accurate diagnosis in 67% of solitary pulmonary opacities.