Objective To investigate the application value of three‑dimensional (3D) recons-truction combined with endoscopic ultrasonography (EUS) in preoperative accurate evaluation of biliary tract neoplasms.

Methods The retrospective and descriptive study was conducted. The clinico-pathological data of 19 patients with biliary tract neoplasms who underwent 3D reconstruction combined with EUS in the Shangdong Provincial Third Hospital from January 2019 to October 2022 were collected. There were 13 males and 6 females, aged 64(range, 35-75)years. All patients underwent preoperative abdominal enhanced computer tomography (CT) thin‑slice scan with 3D reconstruction combined with EUS. Some patients further received other endoscopic techniques such as intraductal ultrasonography, endoscopic retrograde cholangiopancreatography or SpyGlass cholangioscopy to obtain tumor tissues for histopathology evaluation. The surgical implementation protocol was developed based on the results of 3D reconstruction and EUS. Observation indicators: (1) results of 3D reconstruction; (2) results of EUS; (3) comparison between preoperative surgical protocol and actual intraoperative conditions. Measurement data with skewed distribution were represented as M(range), and count data were described as absolute numbers and/or percentages.

Results (1) Results of 3D reconstruction. Results of 3D reconstruction in 19 patients with biliary tract neoplasms showed morphology of the liver, bile ducts, pancreas, blood vessels, and duodenum, including 4 cases of hilar cholangiocarcinoma, 14 cases of middle and lower cholangiocarcinoma, and 1 case of intrahepatic cholangiocarcinoma. The accuracy of 3D reconstruction in 19 patients was 18/19. (2) Results of EUS. All 19 patients underwent preoperative EUS, including 7 cases obtained tumor tissue for histopathology evaluation, with the results indicating abnormal hyperplasia or malignant tumor. The rate of histopathology evaluation was 7/19, with the sensitivity as 7/7. Of 19 patients, results of EUS in 2 cases indicated positive of lymph node metastasis, but results of postoperative histopathology evaluation indicated negative of lymph node metastasis in lymph node specimens. Results of EUS in the rest of 17 cases indicated negative of lymph node metastasis, but results of intraoperative laparoscopic exploration on 1 case indicated extensive intra‑abdominal metastasis. (3) Comparison between preoperative surgical protocol and actual intraoperative conditions. Of 19 patients, 18 cases underwent radical resection and 1 case underwent bile duct drainage, with the compliance rate between preoperative surgical protocol and actual intraoperative conditions as 18/19. The volume of intraoperative blood loss in the 18 cases receiving radical resection was 336(range, 50-1500)mL. Two cases had postoperative complications.

Conclusion Results of 3D reconstruction combined with EUS can accurately map the the size, location, extent of bile duct invasion, and adjacent relationships of surrounding tissues of malignant biliary tract neoplasms, for preoperative accurate evaluation and surgical planning.