Imaging anatomy and clinical significance of the inferior pancreaticoduodenal veins

Objective To investigate the imaging anatomy and clinical significance of the inferior pancreaticoduodenal veins (IPDVs). Methods The retrospective and descriptive study was conducted. The clinicopathological data of 42 patients with pancreatic head ductal adenocarcinoma who were admitted to Peking Union Medical College Hospital from January to June 2018 were collected. There were 24 males and 18 females, aged from 41 to 78 years, with an average age of 61 years. Patients received preoperative contrast-enhanced computed tomography (CT) examination with 1 mm slice thickness, and underwent corresponding surgery according to the preoperative evaluation. Observation indicators: (1) results of preoperative CT examination; (2) surgical situations. Normality of measurement data was analyzed using Shapiro-Wilk test. Measurement data with skewed distribution were described as M (QR) or M (range), and comparison between groups was analyzed by the Mann-Whitney U test. Count data were described as absolute number or percentage, and comparison between groups was analyzed by the chi-square test. Results (1)Results of preoperative CT examination: 42 patients received preoperative contrast-enhanced CT examination with 1 mm slice thickness.① The first jejunal venous trunk was identified in all the 42 patients. The first jejunal venous trunk crossed dorsal to the superior mesenteric artery (SMA) in 34 patients and ventral to the SMA in 8 patients. ② Of 42 patients, 2 showed no IPDV, and 40 showed IPDV including 23 with 1 IPDV, 13 with 2 IPDVs, 3 with 3 IPDVs, and 1 with 4 IPDVs. A total of 62 IPDVs were identified in the 42 patients, with an average IPDV number of 1 (range, 0-4). There were 43 IPDVs drained into first or second jejunal venous trunks and 19 IPDVs drained into superior mesenteric vein (SMV). ③ Of 42 patients, type Ⅰ IPDV was identified in 32 patients including 20 with 1 IPDV drained into jejunal venous trunk at dorsal side of SMA, 7 with 2 IPDVs drained into jejunal venous trunk at dorsal side of SMA, 2 with 3 IPDVs drained into jejunal venous trunk at dorsal side of SMA, and 3 with 1 IPDV drained into jejunal venous trunk at ventral side of SMA, and non-type Ⅰ IPDV was identified in 10 patients; type Ⅱ IPDV was identified in 18 patients including 17 with 1 IPDV drained into SMV and 1 with 2 IPDVs drained into SMV, and non-type Ⅱ IPDV was identified in 24 patients. Some patients can simultaneously had type Ⅰ and type Ⅱ IPDV. (2) Surgical situations: 42 patients underwent pancreatoduodenectomy, 14 of which underwent laparoscopic surgery and 28 underwent open surgery. There were 5 cases with SMV or portal vein reconstruction, and 18 with intraoperative blood transfusion. All the 42 patients were diagnosed as pancreatic ductal adenocarcinoma by postoperative pathological examination, including 30 of R0 resection and 12 of R1 resection. The volume of intraoperative blood loss, cases with intraoperative blood transfusion, cases with R0 and R1 resection (situation of surgical margin), cases with SMV or portal vein reconstruction were 650 mL(853 mL), 15, 20, 12, 4 in the 32 patients with type Ⅰ IPDV, and 475 mL (480 mL), 3, 10, 0, 1 in the 10 patients with non-type Ⅰ IPDV; there were significant differences in the volume of intraoperative blood loss and situation of surgical margin(Z=94.000, χ2=5.250, P 0.05). Conclusions IPDVs can be distinguished on the contrast-enhanced CT with slice thickness, and classified as IPDVs drained into SMV or jejunal venous trunk. It is necessary to carefully deal with IPDVs drained into jejunal venous trunk in the pancreaticoduodenectomy due to its more volume of intraoperative blood loss and lower R0 resection rate. Key words: Pancreatic ductal neoplasms; Pancreatic ductal adenocarcinoma; Inferior pancreaticoduodenal vein; Pancreaticoduodenectomy; Imaging characteristics; Computed tomography, X-ray