**2.2. Segmental volume measurement**

By using the surgical simulation module of Hisense CAS, watershed analysis was performed based on the portal vein arrangement, radius, and supply area. The volumes of liver segments for types A, B, and C were calculated based on the fourthlevel branch of the portal vein. Type D varied greatly and the number of each variant was small.

#### **2.3. Basic principle for Dong's liver segmentation**

Based on statistical analysis, approximately 10% of cases were selected for preverification. Preliminary segmentation was performed and segmentation principles were proposed; these were verified by using the larger sample. The following basic principles for liver segmentation were developed based on the statistical analysis of preexperimental results obtained by the 3D reconstruction of the normal liver and vascular system of 120 humans.


### *2.3.1 I 3D reconstruction and intrahepatic vascular system Based on Artificial Intelligence*

The 3D reconstruction of the liver and intrahepatic vascular system was performed for 759 patients of different ages. The reconstructed digital liver by use of machine learning appeared to have a clear structure (**Figure 1**). The spatial distribution and variation of the portal vein were observed in rotated directions, leading to the observation of the spatial anatomical relationships of the portal vein within the liver from different angles.
