OBJECTIVETo assess the value of dynamic enhanced CT scanning in diagnosis of pulmonary nodules.

METHODSSixty-nine patients with pulmonary nodules underwent examination with dynamic enhanced CT scanning. Of these patients, 53 with definite diagnoses confirmed by histological or clinical data were divided into three groups according to the nature of the nodules, namely the malignant group (n=34), benign group (n=13) and active inflammatory group (n=6). The time-density curve (T-DC) and the corresponding parameters of these patients were compared.

RESULTSSignificant differences in the net enhancement and S/A ratio were found among the 3 groups (P<0.001). The active inflammatory nodules showed the highest enhancement, followed by malignant nodules and then by benign nodules, with significant differences between any of the two groups (P<0.05). At the diagnostic threshold of net enhancement by 25 Hu or S/A ratio by 10% for malignant nodules, a higher negative predictive value and accuracy were obtained. The difference in the wash-out value among the 3 groups was statistically significant (P<0.05). When diagnostic criteria for malignancy was defined by a wash-in value of 25 Hu or higher and wash-out value of 0-35 Hu, the false-positive rate was decreased from 57.89% to 47.37%.

CONCLUSIONThe application of 16-slice spiral CT and its CT perfusion software allows convenient dynamic enhancement study of pulmonary nodules and can be helpful in their differential diagnosis.