Objective To investigate the anatomy of middle hepatic vein and its tributaries in liver based on three-dimensional visualization technology.

Methods The retrospective and descriptive study was conducted. The clinical and imaging data of 100 healthy adults who under-went liver enhanced computed tomography (CT) examination in the First Affiliated Hospital of Nanjing Medical University from November 2018 to September 2019 were collected. There were 47 males and 53 females, aged from 20 to 83 years, with an average age of 52 years. The three-dimensional reconstruction and data measurement of thin-layer liver CT images of 100 healthy adults were performed using Hisense computer-aided operation system. The three-dimensional reconstruction of liver, portal vein and hepatic vein was conducted on every healthy adult to detect the anatomical situations. Observation indicators: (1) liver volume; (2) the location relationship between middle hepatic vein and Rex-Cantlie's line; (3) the location relationship between middle hepatic vein and dividing line of the left and right liver located in the portal vein drainage area; (4) simulation of anatomical hepatectomy; (5) tributaries of middle hepatic vein. Measurement data with normal distribution were represented as Mean±SD, and measurement data with skewed distribution were represented as M (range). Count data were described as absolute numbers.

Results (1) Liver volume: the liver volume of 100 healthy adults was 1 248.8 mL (range, 785.5-3 745.6 mL). (2) The location relationship between middle hepatic vein and Rex-Cantlie's line: of 100 healthy adults, middle hepatic vein overlapped with Rex-Cantlie's line in 75 cases and middle hepatic vein deviated to the right of Rex-Cantlie's line in 25 cases. (3) The location relationship between middle hepatic vein and dividing line of the left and right liver located in the portal vein drainage area: of 100 healthy adults, middle hepatic vein overlapped with the inferface of the left and right liver guided by portal vein drainage area in 76 cases, the starting segment of middle hepatic vein deviated to the right of the dividing line and the proximal inferior vena cave segment overlapped with the dividing line in 24 cases, no middle hepatic vein deviated to the left of interface of the left and right liver guided by portal vein drainage area. (4) Simulation of anatomical hepatectomy: the length of liver parenchyma separated in the simulated anatomical hepatectomy of 100 healthy adults was 121.7 mm (range, 91.3-177.2 mm), and the distance between gallbladder fossa and middle hepatic vein was 17.8 mm (range, 6.5-35.8 mm). (5) Tributaries of middle hepatic vein: a total of 507 tributaries of the middle hepatic vein were reconstructed in 100 healthy adults. There were 61 tributaries in the segment 4a of liver, 147 tributaries in the segment 4b of liver, 190 tributaries in the segment 5 of liver and 109 tributaries in the segment 8 of liver, respectively. The numbers of tributaries of middle hepatic vein in segment 4a, 4b, 5 and 8 of liver of 100 healthy adults were 1 (range, 0-1), 1 (range, 0-3), 2 (range, 0-4), and 1 (range, 0-2), respectively. The root diameters of tributaries of middle hepatic veins in segment 4a, 4b, 5 and 8 of liver of 100 healthy adults were 3.6 mm (range, 2.2-8.1 mm), 3.7 mm (range, 2.0-6.6 mm), 3.6 mm (range, 2.2-6.8 mm) and 3.5 mm (range, 2.3-7.9 mm), respectively. The distances between gallbladder fossa and middle hepatic vein were 103.9 mm (range, 76.9-130.0 mm), 59.1 mm (range, 12.0-115.3 mm), 54.2 mm (range, 22.8-95.9 mm), 103.9 mm (range, 66.5-144.2 mm), respectively. Using the data of location and diameter of tributary roots of middle hepatic vein, it could draw location map of the root of tributaries of middle hepatic vein in the simulation of anatomical hepatectomy.

Conclusion Reconstruction of hepatic vascular system by three-dimensional visualization technology can display the anatomy and location map of the root of tributaries of middle hepatic vein.