To investigate the 64-slice spiral CT imaging characteristics of solitary pulmonary nodules (SPNs) and improve the diagnostic accuracy for benign and malignant SPN.

A total of 170 patients who were pathologically diagnosed with SPNs were eligible for the enrollment between August 2015 and December 2018 at the Second People's Hospital of Lianyungang, including 116 with lung adenocarcinomas (LACs) and 54 with benign nodules (BNs). The χ² test was used to compare the differences of CT findings (such as nodule position, morphology, and composition, tumor-lung interface, burr sign at the edge of the tumor, pleural violation, and bronchial amputation) and the patterns of enhancement, while the t test was applied for comparing the differences of the size of the lesions and the distance to pleura.

There were significant differences in the solid and sub-solid nodules (42.2% vs 22.2%, 44.8% vs 29.6%), irregular pattern (88.7% vs 35.2%), rough tumor-lung interface (77.6% vs 22.2%), lobulated morphology (62.9% vs 14.8%) , burrs at the edge of the tumor (56.9% vs 3.7%), and pleural invasion (45.7% vs 3.7%) between LACs and BNs (χ²=25.17, 52.24, 47.03, 23.54, 43.43 and 29.66, respectively; P＜0.05). There was no statistically significant difference in the size of the lesions or the distance to pleura between the two groups (P＞0.05). In the arterial period, the proportion of lesions with mild to moderate uneven enhancement was significantly higher in LACs than in BNs (57.4% vs 28.6%), whereas the proportion of lesions with pronounced enhancement was significantly lower in the BNs group (35.2% vs 53.5%; χ²=4.68, P＜0.05). In the venous period, the proportion of lesions with delayed enhancement was significantly higher in LACs than in BNs (83.3% vs 53.5%), while the proportion of lesions with hypoenhancement was significantly lower in the BNs group (9.2% vs 46.5%; χ²=64.23, P＜0.05).

CT is the main method for detection of pulmonary nodules, and the combination of CT characteristics and enhancement features can improve the diagnostic accuracy, thus improving the clinical management of malignant nodules.