Multi-slice Spiral CT Diagnosis And Differential Diagnosis Of Solitary Pulmonary Nodules

Objective: To analyze the various CT findings of solitary pulmonary nodules and to assess their diagnostic value in distinguishing benign nodules from malignant nodules. Methods: CT (including post-processing data) and clinical data of 105 patients with a solitary pulmonary nodule proved by pathology/clinical follow-up were analyzed retrospectively. Results: There were 58 malignant (lung cancer [n=57], cancer sarcoma [n=1]) and 47 benign nodules (tuberculoma[n=26], inflammatory lesions [n=14], hamartoma [n=4], pulmonary cyst [n=2], sclerosing hemangioma[n=1]). Occurrence rate of lobulation, short spiculation, vascular convergence, pleural indentation and vacuole sign or air bronchogram for malignant nodules (72.4%, 65.5%, 51.7%, 53.4%, 36.2%, respectively) was significantly higher than that for benign nodules(25.5%, 8.5%, 8.5%, 23.4%, 10.6%, respectively, P<0.05). But no statistical significance between the bronchioloalveolar carcinoma and non-bronchioloalveolar carcinoma groups regarding those signs(P>0.05). While the sensitivity,specificity and diagnostic accuracy for malignancy were high up to 81.0%, 80.9%, 81.0%, respectively,with the coexistence of two or more signs mentioned above, the false positive and the false negative rate were as low as 19.2% and 19.0%, respectively. The incidence of smooth, well defined margins (74.5%) and long spikes (29.8%) was higher in benign nodules than that of malignant nodules; Since calcifications were observed in 21.3% of benign nodules, there was statistical significance between malignant and benign nodules(P<0.05). In addition, the patients'age, nodule location and clinical symptoms could serve as important reference for the diagnosis and differential diagnosis. Conclusion: The coexistence of two or more signs among lobulation, short spiculation, vascular convergence, pleural indentation and vacuole sign or air bronchogram with the additional support by contrast enhancement characteristics can improve the diagnostic accuracy for malignant nodules.