To explore the diagnostic value of computed tomography (CT) value for perihepatic lymph node metastasis of primary liver cancer (PLC).

Clinical data of 14 patients undergoing PLC resection + lymph node dissection in Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine between October 2001 and January 2015 were retrospectively analyzed. The informed consents of all patients were obtained and the local ethical committee approval was received. Among the patients, 8 were males and 6 were females with the age ranging from 36 to 73 years old and the median of 51 years old. Fifteen groups of suspicious positive lymph nodes of the 14 patients were detected by enhanced CT scan before operation, and were divided into the positive group (n=8) and the negative group (n=7) according to the postoperative pathological examination. The differences in plain CT value, arterial phase CT value and coefficient of variation (CV) of arterial phase CT value of the lymph nodes between two groups were compared. And the diagnostic accuracy of the lymph node metastasis by these indexes was analyzed. The observation indexes of two groups were compared using t test and the analysis on the diagnostic accuracy of lymph node metastasis was conducted using receiver operating characteristic (ROC) curve.

The plain CT value, arterial phase CT value and CV of arterial phase CT value were respectively (30±4) HU, (45±10) HU and (30±10)% in the positive group, and were respectively (43±5) HU, (65±18) HU and (17±6)% in the negative group, and significant differences were observed between two groups (t=-5.400, -2.660, 2.990; P<0.05). ROC curve analysis showed that the cut-off value of plain CT value, arterial phase CT value and CV of arterial phase CT value was respectively 38 HU, 54 HU and 22%, and the diagnostic accuracy was respectively 100%, 80% and 80%.

CT value has certain diagnostic value for perihepatic lymph node metastasis of PLC. Perihepatic lymph node metastasis is likely to occur when plain CT value<38 HU, arterial phase CT value<54 HU and CV of arterial phase CT value>22%.