Ten radiograph signs were assessed by two experts for their usefulness in the diagnosis of small solitary peripheral pulmonary nodules less than 3 cm. The ten categories included notching, spicula formation, pleural indentation, vascular convergence, contour, paleness, homogeneity, cavitation, air bronchogram, and calcification. The cases included 134 lung cancers and 44 benign lung lesions resected between 1972 and 1988 at the Second Department of Surgery, Okayama University Medical School. Notching, spicula formation, pleural indentation, vascular convergence, contour, and air bronchogram were useful signs in differentiating lung cancer from benign lung lesions. However, since the radiograph signs exhibited great variation in both lung cancer and benign lung lesions, a diagnostic operation is sometimes inevitable.</p
