**Abstract**

A good understanding of liver anatomy is required for performing precise liver resection. However, the currently described methods of liver segmentation based on portal and hepatic veins are inconclusive. We proposed a system of liver segmentation based on previous reports and our data. Three-dimensional computed tomography software based on artificial intelligence was used to analyze the portal vein branching pattern in 759 patients. We analyzed four different types of liver segmentation and measured their respective segmental liver volumes. We classified four types of liver segmentation based on the right portal vein. Median segmental liver volumes were variable for the different types of segmentation. Our system of liver segmentation enables a better classification of individual patients into one of the different types, thus assisting in preoperative surgical planning. Segmental liver volume is useful for the preoperative evaluation of remnant liver volume.

**Keywords:** liver anatomy, portal vein, segmentation, liver volume, computer-assisted surgery
