Objective To investigate the diagnostic value of dualsource computed tomography (CT) for the lymphatic metastasis of the pancreatic head cancer. Methods The clinical data of 52 patients with pancreatic head cancer who were admitted to the Southwest Hospital from December 2007 to December 2009 were retrospectively analyzed. All patients received plain and enhanced scan by dualsource CT, and the distributions, number, short and long axis diameters and ratio of short to longaxis diameter, enhancement modality and enhancement degree of lymph nodes were recorded by comparing the CT images and the pathological results. Different diagnostic thresholds including shortaxis diameter greater than or equal to 5 mm, 8 mm or 10 mm were used as the criteria for judging lymph node metastasis. The sensitivities, specificities, positive and negativepredictive values and the accuracies of the 3 criteria were calculated respectively. All data were analyzed using the t test or chisquare test. Results The positive rate of lymph node metastasis of the 52 patients was 67.3%(35/52). Lymph node metastases were found in 118 out of 163 lymoh nodes. The metastatic rates of No.13 and 17, 12, 14, 16 lymph nodes were 80.0%(28/35), 85.7%(30/35), 97.1%(34/35), 20.0%(7/35), respectively. The increased CT value of metastatic lymph nodes was (25.0±3.3)HU, which was significantly higher than (14.0±2.0)HU of patients with negative metastatic lymph nodes (t=22.732, P<0.05). The short and longaxis diameters and the ratio of short to longaxis diameter showed significant difference between metastatic and negative lymph nodes (t=3.732, 3.354, 3.430, P<0.05). The positive rate of lymphatic metastasis with rimlike enhancement was 100.0%(56/56), which was significantly higher than 71.0%(76/107) of lymphatic metastasis with homogeneous enhancement (χ2=18.198, P<0.05). Using the short axis diameters≥5 mm, 8 mm and 10 mm as the standards for diagnosing lymph node metastasis, the sensitivities of the dualsource CT were 99.2%, 43.2% and 18.6%, the specificities were 22.2%, 77.7% and 88.9%, the positive predictive values were 77.0%, 83.6% and 81.5%, and the negative predictive values were 10/11, 34.3% and 29.4%, respectively. Conclusions Dualsource CT could detect lymph node metastasis of the cancer of the head of pancreas without causing trauma. When the rimlike enhancement and increased value after enhancement>20 HU, short axis diameter of the lymph nodes≥8 mm, high sensitivity of dualsource CT for the diagnosis of lymph node metastasis of cancer of the head of pancreas could be achieved.