{'fraction_non_alphanumeric': 0.011432654519471239, 'fraction_numerical': 0.0010718113612004287, 'mean_word_length': 5.306306306306307, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A system for the virtual planning of liver surgery

ABSTRACT Because of the enormous individual anatomical variability oncological liver surgery is an important field for using computeraided methods during the operation planning phase. The preoperative analysis of the image data provides an individualimpression regarding the location of the tumor and the exact structure of the vessel system. This has a great significancebecause surgical planning in this field is based on the location of the liver sub-segments. The detection of these surfaces andthe position of the tumor inside the segmental structure provides an estimation about the operability of a patient. This paperpresents a system for the virtual planning of liver surgery that was implemented on the base of an object oriented white boxframework.Keywords: Computer assisted surgery, computer tomography, liver resection, operation planning. 1. INTRODUCTION The aims of a software which provides operation planning for oncological liver surgery have to be an objective selection ofthe patients with respect to an estimated postoperative liver function and operation planning which is as precise as possible.These two properties belong together because an estimation of postoperative liver function is based on an individualplanning procedure for the resection of a tumor [1]. The planning procedure results in a proposal which areas of the livertissue have to be removed and what will be the size of the remaining liver volume. This value may be interpreted as anapproximated value for liver functionality and may be used for patient selection.For the virtual planning of liver surgery is the determination of the anatomical liver-segments and sub-segments animportant step. The approaches to calculate the different parts of the liver are based on the individual anatomy, which isdefined by the structure of the intrahepatic vessel system. Couinaud proposed an anatomical model to subdivide the liverinto eight segments with the aid of artificial planes [2]. Another approach calculates the segmental classification by meansof an analysis of the portal veins structure. It defines partial volumes of the liver tissue which are assigned to the differentbranches of the vessel tree. The location of the interfaces between these segments is a significant surgical informationadditional to the position of the tumor and its relation to the vessel system. Additionally those tissue areas which aredependent on branches located inside the safety margin are detected. These volumes probably have to be resected as well.The integration of computer aided operation planning in this field requires that all steps of the analysis process have to beembedded in a system which enables the reception of image data and the forwarding of the results.