A Study On The Measurement Method Of Quasi-static Three-dimensional Knee Joint Movement Based On The Image Registration Of CT And Ultrasound Images

The measurement method of quasi-static three-dimensional knee joint movement is an important basis for studying the mechanism of knee joint injury.It is of great significance for establishing safe and accurate knee joint motion evaluation system,early diagnosis and standardized medical rehabilitation.The existing measurement methods have the disadvantages of invasion,radiation,low accuracy and high cost.With the development of medical ultrasound imaging technology,ultrasonic detection has been widely used in clinical.Compared with computer tomography and nuclear magnetic resonance imaging technology,ultrasonic imaging has the advantages of low cost and no ionizing radiation.Therefore,through the introduction of ultrasonic images,this paper innovatively proposes a three-dimensional motion measurement system of knee joint based on CT images and ultrasonic images registration technique without invasive,ionizing radiation and high precision.This paper mainly discusses the realization principle of the measurement method of three-dimensional knee joint movement based on the image registration of CT and Ultrasound,including the system composition,data acquisition,the selection and construction of the image structure for registration,the construction of the registration framework,the reconstruction of the three dimensional model of the knee joint and the visual simulation of the motion.The construction of registration framework is the core of the whole system.Firstly,because the CT image and B-mode image are medical images under different modes,the difference of the resolution and gray attribute is great.In view of this,we need to use the ultrasonic imaging simulation algorithm to simulate the CT images into ultrasonic images for image registration.Secondly,in the selection of the image structure,in order to obtain more accurate registration results,this paper introduces a cross graph,a H-shaped graph and an image structure like Chinese character ‘wang' for the image registration algorithm;and finally,The maximum normalized mutual information is used to describe the correlation between two images.The parallel particle swarm optimization algorithm based on GPU acceleration isapplied to search for the optimum solution.In order to verify the feasibility of the cross graph,H-shaped graph and the image structure like Chinese character ‘wang' as the image structure in the registration algorithm,the related experiments were carried out in this paper.The results show that,considering the balance of time and the the measurement precision,the H-shaped graph is finally selected.Furthermore in vitro and in vivo experiments were completed.The experimental results show that the measurement method of three-dimensional knee joint movement can accurately measure the three-dimensional motion of the knee joint and meet the needs of the three dimensional motion analysis of the knee joint.