Research On Hepatic Vascular System Segmentation And Visualization In CT Images

The liver tumor thermal ablation technology refers to insert the needle into the liver tumor lesion area,ablating the tumor by the heat generated from microware or radio frequency.Due to the complex intrahepatic vascular system,including hepatic vein,portal vein,hepatic artery,common bile duct,lymph vessels,etc.complicated the surgery path planning of tumor thermal ablation.Furthermore,the blood flow will affect temperature field of thermal ablation,then affect the solidification area.Thus gained the accurate position of the hepatic vasculature is the present clinical problems need to be addressed.In this paper we studied on automatic segmentation hepatic vascular based on liver contrast enhancement CT image,obtaining the accurate position of liver vessels.We realized the segmentation of hepatic vasculature with two steps,enhanced the hepatic vascular and extracted them.The content of this paper included:1.Accomplished two kinds of classic vascular enhancement filter algorithm called vesselness filter and diffusion filter.Specifically incorporated three kinds of vesselness algorithm proposed by Frangi 、 Sato and Erdt,RPM(Regularized Perona–Malik),Vessel Enhancing Diffusion and Hybrid Diffusion with Continuous Switch.We contrast the algorithm,contrast to noise ratio of enhancement and accuracy,sensitivity,and specificity of the final segmentation results using 20 cases of abdominal enhanced CT data in 3Dircadb public data set.Result showed that vesselness algorithm efficiency better than diffusion filter algorithm on average,thereinto vessel enhancing diffusion and hybrid diffusion with continuous switch running time is more than 1.5 times of vesselness algorithm.Contrast to noise ratio of vesselness were higher 2dB than that of diffusion filter,loaded to subsequent algorithm of diffusion computational complexity is high and lower accuracy.2.Implement a kind of automatic hepatic vascular segmentation based on Threshold Level Set algorithm.First of all,made Sigmoid filter to reduce error detection of liver edge,enhance image contrast.Then attempted vascular enhancement algorithm inhibiting rest of organization except the hepatic vascular.Finally,used Threshold Level Set to segment the hepatic vasculature.Experiments conducted on 20 cases of CT images using this algorithm.The result showed that the accuracy of segmentation vessel compared with the manual gold standard higher than 0.74.Compared with other segmentation algorithms,ours algorithm has obvious advantages in accuracy,especially,to relieve the target boundary low contrast under-segmentation phenomenon,in addition to the segmentation results were more complete.This study combined with vascular enhancement algorithm and the Threshold Level Set,implemented the automatic segmentation of hepatic vasculature.Provided more scientific and intuitionistic image positioning for the doctor,to offer the technical support for accurate liver tumor thermal ablation technology.