Studies On Application Of Three-dimensional Visualization In Microwave Ablation Of Liver Cancer

Purpose:1. To verify the feasibility of the three-dimensional (3D) visualization softwaresystem for tumor ablation in the treatment planning and the treatment response assessmentof microwave ablation (MWA) for liver cancer.2. According to randomized controlled trialrequirement, the treatment response of MWA for liver cancer guided by3D visualizationtreatment planning was compared with two-dimensional (2D) image treatment planning toassess the efficacy of the3D visualization software system used in the treatment planningof MWA.3. In a controlled clinical study, the accuracy of evaluating the treatmentresponses of MWA used the3D visualization method was compared with the2D imagemethod to assess the efficacy of the3D visualization software system used in evaluatingthe treatment responses of MWA.4. To observe the effect of the3D visualization softwaresystem for tumor ablation based on MRI data in the treatment planning of MWA for livercancer through the experimental research and preliminary clinical study.Materials and methods:1. The study on treatment planning: From July2012toSeptember2013, according to enrollment standard,108cases (145nodules) were enrolledin a randomized control study. All cases were randomly divided into two groups accordingto admission order. In the3D treatment planning group,55cases (74nodules) underwentthe treatment planned by the3D visualization software before MWA. In the2D treatmentplanning group,53cases (71nodules) underwent the treatment planned by the2D medicalimages before MWA. The items of these two groups were compared prospectivelyincluding insertion number, treatment time, success rate of first ablation, techniqueeffectiveness rate and local tumor progression rate.2. The study on evaluating treatmentresponses: From July2012to October2013, according to enrollment standard,71cases (93nodules) treated with ultrasound-guided MWA were enrolled in the study. After MWA, the3D visualization method and the2D image method were used respectively to evaluate thetreatment responses. The relationship of the results of the two evaluation methods with the local tumor progression was analyzed. The relationship of the minimum ablation marginwith the local tumor progression was also analyzed. The CT data (slice thickness,1.25mm)were used in the above two studies for3D visualization software system.3. Thepreliminary study of the3D visualization software system based on MRI data:(1) Thereconstruction precision analysis of the3D model: The actual measured values of modelssize and volume were compared with the automatic measured values of the3Dreconstruction models based on the CT data with different slice thickness (1.25mm or5mm).(2) The preliminary study on treatment planning: From December2012to October2013,21cases (21nodules, tumor size≥3cm) treated with ultrasound-guided MWA wereenrolled in the study. The MRI data with slice thickness of5mm were imported into the3Dvisualization software system for the treatment planning. The treatment responses wereevaluated by follow-up.Results:1. The study on treatment planning: The3D treatment planning of all cases wereperformed successfully. For larger tumors (tumor size≥3cm), the insertion number andtreatment time in the3D treatment planning group were more than those in the2Dtreatment planning group (P<0.05), however, the local tumor progression rate in the3Dtreatment planning group was lower than that in the2D treatment planning group (P<0.05).Tumor size was the influencing factor of the success rate of first session of ablation(P=0.008) and the local tumor progression rate (P=0.007).2. The study on evaluatingtreatment responses: The3D visualization evaluating of the treatment responses wasperformed successfully in93.0%of cases. The percentage of the larger tumors (tumorsize>3cm) that achieved the safe ablation margin was significantly lower than that of thesmaller tumors (tumor size≤3cm). The3D visualization method was better than the2Dimage method on evaluating the ablation margin. The minimum ablation margins of alltumors with local tumor progression were equal or small than3mm.3.The preliminarystudy of the3D visualization software system based on MRI data:(1) The reconstructionprecision based on the CT data with slice thickness of1.25mm was better than the CT datawith slice thickness of5mm. The length measurement error of the3D models (size≥3cm)reconstructed by the CT data with slice thickness of5mm was minor. When performing the treatment planning for MWA of liver cancer using the3D visualization software systembased on the MRI data, the technique effectiveness rate and the local tumor progressionrate were95.2%and9.5%, respectively.Conclusion:1. The3D visualization software system for tumor ablation is feasible andeffective in the treatment planning and the treatment response assessment of MWA for livercancer.2. The3D visualization treatment planning can decrease the local tumorprogression rate of MWA for liver tumor (size≥3cm).3. The3D visualization method forevaluating the treatment responses can achieve the accurately quantitative evaluation ofablation margin.4. The3D visualization software system based on the MRI data has apromising application prospect in the treatment planning of MWA for liver cancer.