[CT diagnosis of pulmonary solitary nodule--a correlative study of CT, X-ray and pathology]

A correlative study of CT, X-ray and pathology was done on 41 cases with pulmonary solitary nodule, including peripheral lung cancer 30 cases, benign lesion 10 and metastatic tumor 1. Results showed that CT was more sensitive than conventional X-ray in depicting the characteristic signs such as spiculate protuberance, minute calcifications, small vacuole sign and retraction of pleura. 2 mm thin slice CT scanning is helpful in differential diagnosis of lesions less than 2 cm in diameter. Correlation of CT findings with pathology indicated that spiculate protuberance was caused by infiltrative growth of tumor, whereas the small vacuole sign represented remnant of air containing cavity or slit. The shaggy border of inflammatory nodule was the result of extension of inflammatory process. A correct diagnosis of pulmonary solitary nodule lies in comprehensive analysis of CT manifestations. There is greater possibility of malignancy with mass greater than 4 cm in diameter, lobulation and spiculation are frequently present. Lung cancer less than 3 cm in diameter often presents as lobulated mass with spicules, small vacuole sign and pleural retraction.