Lymph nodes metastases of biliary tract carcinoma:evaluation with spiral CT / 重庆医科大学学报

ABSTRACT

Objective:To evaluate the distribution of lymph nodes metastases(LNM) in upper and middle abdomen from primarybiliary tract carcinoma and the imaging features of metastatic lymph nodes on contrast spiral CT scanning.Methods:A retrospective study was performed,consisting of 41 cases of biliary tract carcinoma(24 cases of extrahepatic cholangiocarcinoma and 17 cases of gallbladder cancer),with upper and middle abdominal LNM identified by surgically and pathological procedure.All patients underwent CT scanning with intravenous contrast-enhancement on single-slice or 16-slice spiral CT.According to the LN location,upper and middle abdominal LN was classified as eight sites in this study as followsporta hepatis,hepatoduodenal ligament,gastrohepatic ligament,gastrocolic ligament,gastrosplenic ligament,celiac,superior mesenteric and paraaortic area.Anatomic distribution and CT appearances of metastatic LN were observed.Results:(1)The incidence of LNM in each site from biliary tract carcinoma was19.5%(8/41)in porta hepatis,90.2%(37/41)in hepatoduodenal ligament,22%(9/41)in gastrohepatic ligament,63.4%(26/41)in celiac,39%(16/41)in superior mesenteric and 48.8%(20/41) in paraaortic area respectively.Hepatoduodenal ligament lymphonode was the most common site of LNM from primary biliary tract carcinoma.The patients with gallbladder carcinoma had more LN sites involved than extrahepatic cholangiocarcinoma.(2)The MSAD(Maximum Short Axis Diameter)of metastatic LN varied from 1.4 to 4.8 cm.The density of most of metastatic nodes was hypoattenuation or iso-attenuation,and necrosis of metastatic LN was found in 69% sites and occurred more frequently in metastatic LN with MSAD ≥2.5 cm.Necrosis of metastatic LN could be categorized as 3 typesno obvious necrosis was found(type 1,31%);the volume of necrosis region was less than 1/2 in metastatic LN(type 2,24.1%);the volume of necrosis region was more than 1/2 in metastatic LN(type 3,44.8%).Conclusion:Distribution of LNM is determined by the lymphatic drainage route of biliary tract.The patients with gallbladder carcinoma have more LN sites involved than extrahepatic cholangiocarcinoma.Hypoattenuation or iso-attenuation compared with crura of diaphragm,heterogeneous enhancement,incomplete patterns of necrosis,is the image feature of upper and middle abdominal metastatic lymph nodes from biliary tract carcinoma on spiral CT scanning with bolus intravenous contrast-enhancement.