The Studies Of Construction And Clinical Application Of Image-guided Three Dimensional Visualization Thermal Ablation Platform

With the development of image-guided thermal ablation, thermal ablationtechnique has become one of the curative methods for liver cancer. To obtain a goodclinical efficacy, scientific planning in the preoperation, intraoperative precisepositioning, and accurate postoperative assessment are the three key steps in the courseof thermal ablation treatment, these three steps are interrelated, mutual transferred andmutual feedback. However, it is still lack of scientific planning method for tumorthermal ablation during preoperative planning; preoperative planning can not beexecuted accurately during the intraoperative positioning and intraoperative treatmentinformation is difficult to directly apply to the postoperative evaluation. Therefore, athree-dimensional visualization platform which can be applied in the entire process(including preoperative planning, intraoperative positioning, and postoperativeevaluation) was built in this study, based on the preliminary study of the research team,combined medical image processing and analysis technology, navigation technologyand thermal ablation technology. The three-dimensional visualization platformincludes three sub-platform systems: preoperative planning, intraoperative positioningand postoperative evaluation. The three sub-platform systems are independent, so thisarticle was divided into three parts and introduced the building, validation andapplication of the three sub-platform systems respectively.Preoperative planning platform: Focusing on characteristics of image-guidedpercutaneous thermal ablation for liver tumor and clinical needs of practicalapplication, combined with the simulation ultrasound techniques, three-dimensionalimage processing and analysis methods and navigation technology, we put emphasison the simulation of ultrasound algorithm and the ultrasound image generation, thethree-dimensional model of thermal ablation for liver tumor, and the study of puncture path meeting clinical practice needs, in order to establish the three-dimensionalvisualization preoperative planning platform of thermal ablation for liver tumor undersimulate ultrasonic condition. In verification of the platform, we have innovativelyproposed a simulated experiment method based on real clinical data, which reallysimulated the environment of the clinical preoperative planning, objectively evaluatedthe value of preoperative planning platform. On this basis, we conducted a preliminaryclinical application and obtained a better clinical efficacy.Intraoperative positioning platform: We verified the precision of the commercialnavigation system by in vitro experiments, and the precision error was about1.631.06mm, which could meet the requirement of clinical application. Then we studiedmicrowave ablation for liver tumors which was unclear in conventional ultrasoundunder the guidance of the virtual navigation technology, and the technical efficiencywas94.44%. The results proved the virtual navigation technology was feasible andeffective in positioning of thermal ablation for liver tumor. On the basis of this study,we combined with3D visualization and navigation technology, focusing on theresearch of navigation parameters interface and image registration fusion, achieved thefusion of2D ultrasound image and3D visualization graphics and the display ofnavigation parameters interface, finally built a sub-platform of image-guidedintraoperative positioning in thermal ablation. In addition, we also performed asimulated experiment to verify the sub-platform using real clinical data. The resultsconfirmed that this platform could execute the preoperative planning accurately andimprove the positioning capability of beginners by using it.Postoperative evaluation platform: The quantitative efficacy assessment ofthermal ablation has always been a difficulty problem. We encoded different regions incolor by Moore Witte projection (Mollweide projection) visual display, in order toshow the relationship of the tumor and ablation zone intuitively and quantitatively afterablation, and finally established a3D visualization platform for quantitativelyassessing ablation efficacy. The results of simulated experiments showed that theaccuracy rate of estimating tumor ablation efficacy by using this platform was significantly higher than that by using conventional2D imaging method. So theplatform had a high application value and provided a tool for postoperative scientificassessment of thermal ablation efficacy. We also initially applied the platform to theassessment of clinical tumor ablation efficacy and achieved better clinical results.