[Creation of 3D Stereo and MPR Color Anatomical Charts in the Hepatic Segments]

We used the Voronoi diagram of a computed tomography (CT) application (i.e., CT liver volume measurement) to depict the liver area, and we obtained depictions of the hepatic segments as a three-dimensional (3D) image based on clinical data; this information can be used for the patient's education and for surgical planning. The hepatic segments use the inter-relationships among the eight subsegments illustrated by Couinaud, those indicated by the portal veins and those provided by hepatic veins. The liver has dual portal and arterial innervation, with the thick portal vein intertwined with thin arteries similar to the intertwining of ivy plants. Couinaud divided the liver into eight segments (S1 to S8) based on portal vein casts. The Voronoi diagram estimates the dominant region of the portal vein, divides the liver into segments, and produces 3D images and multiplanar reconstruction (MPR) images in color. To support understanding of Couinaud's eight hepatic segments (which are explained only in the illustration of the frontal view of the liver), using 3D images created by the Voronoi diagram, we created 3D stereo color anatomical charts of the liver that Couinaud's eight hepatic segments can be confirmed from multiple directions. In addition, we created the MPR color anatomical charts of the liver (S1 to S8) that can be confirmed by color from three directions: axial images, coronal images, and sagittal images in the same way. We converted the data of this anatomical chart into an electronic file that provides a tool that can be easily used in radiological examinations, and we were able to make improvements based on requests from users.