A Computer Assistant System For Liver Transplantation Preoperative Planning Based On CT Images

Liver surgeries such as liver transplantation, liver cancer resection or ablation are considered as important treatments of liver diseases such as primary liver cancer in many countries. In traditional surgical planning, a series of medical images are first captured. Then, based on these scans, surgeons need to manually segment and analyze liver structures, and to mentally imagine a 3D model of patient's liver, which are hard tasks for surgeons. Moreover, the information extracted is often not so complete. In recent years, computer assistant systems show great impact on preoperative planning, treatment implementation and postoperative evaluation. To date, several commercial systems have been developed to assist pre-operative planning for liver surgeries in foreign countries. Although some groups have been paying attention to the research of such systems in our country, no such commercialized systems have been released.Thus this thesis study and implement key algorithms in computer assistant liver transplantation preoperative planning system, and develop a demo of such a system to facilitating further clinical exploration and evaluation. The system consists of five parts: liver segmentation, vessel segmentation, vessel classification and analysis, liver segment analysis and virtual surgery. Based on CT images, the system segments liver and vessels automatically, performs quantitative analysis of these structures, displays 3D models and virtual surgery's effect. All of these functions will assist surgeons in achieving accurate quantitative and visual information and making optimal surgical plans.The work and contributions of this thesis include: it studies and implements key algorithms of liver segmentation, vessel recognition and their structure analysis, and liver segment analysis; develops a demo of computer assistant liver transplantation preoperative planning system; automatically segments liver by implementing GVF-Snake algorithm, setting surgeons free from manual segmentation task; performs quantitative analysis of liver and vessels; identifies hepatic vein and portal vein; builds individualized liver segment model of patients; it also provides user interactive tools enabling surgeons to perform virtual resection. The computer assistant liver transplantation preoperative planning system in this paper explores usage of computer techniques in liver surgical planning, and performs meaningful and effective study to elevate automation degree in surgical planning process, to accelerate the process, to release surgeons'burdens, and to enhance accuracy and effectiveness of making pre-surgical planning.