Methodology Of Percutaneous Microwave Ablation Of Thyroid Adenomas Under Ultrasound Guidance And Its Appraisal System Establishment And Application

Part 1 Methodology of percutaneous microwave ablation of thyroid adenomas under ultrasound guidance and monitoringObjective This study aims to establish a treatment proposal of thyroid adenomas by using percutaneous microwave ablation and investigate its techniques, means and steps, safety and efficacy. Methods From June 2006 to March 2010, we conducted contrast-enhanced ultrasound-guided percutaneous MWA of thyroid nodules on 103 patients by using a mircrowave antenna( KY-2100 2450MHz).Investigated and analyzed were the indications of thyroid MWA, the optimal puncture route, the ways of anesthesia administration, protection of vital neck vessels and recurrent laryngeal nerve(RLN) and reduction of bleeding from core biopsy, indicators of ending ablation procedure following a complete ablation. Results A nodule bigger than 20mm in maximal diameter was the best candidate for MWA. Either of two puncture routes could be selected upon the target lesion's location. Areas surrounding to the thyroid capsule needed adequate local anesthesia to kill pain. Liquid-isolating maneuver could effectively protect carotid artery(CCA)and RLN from needle cutting and electrode heating injury. Advanced block of supplying arteries with heating markedly reduced bleeding involved with biopsy. Multipoint and multicenter ablation was essential to a complete coagulation. Filling-defect in the ablated nodules on CEUS was the key sign to terminate ablation procedure. Conclusions Percutaneous MWA was proved feasible, effective, safe and supermicroinvasive for treating thyroid nodules under the way stated here of puncture and technical points and use of CEUS for monitoring.Part 2 Establishment and application of the appraisal system for percutaneous microwave ablation of thyroid adenomas under ultrasound guidanceObjective This study aims to establish an appraisal system for assessing the effectiveness of percutaneous microwave ablation(MWA) of thyroid noduels. Methods Investigated and analyzed were the changes of volume and elasticity about thyroid nodules by using new technologies such as elastosonography and three-Dimensional(3D) volume reconstruction; the indicators of ending ablation procedure following a complete ablation and defining recurrence or not by using contrast enhanced ultrasound(CEUS); clinical follow up, thyroid hormone determination and pathologic diagnosis simultaneously.Results The volume of thyroid nodules (vs pre- MWA) increased at the 1st,2nd week and 1m after MWA, but decreased from the third month(P<0.05) with a significant shrinkage at the sixth month(P<0.001)during follow up. The SR value of ablated area to surrounding nomal thyroid elevated significantly shortly post MWA(P<0.001)but dropped down from the third month. Filling-defect within the ablated region on CEUS was a key sign to terminate ablation procedure, and persistent absence of tumor reccurence as well. The 1st week determination found a transitory increase in the level of FT4, while the repeated assessment revealed a level back to normal. TSH level was accordingly found to lower beyond normal range and recover 1 month later. Pathologic findings showed swollen cells, necrosis and carbonation over the ablated area. Conclusions It is necessary to build an appraisal system for percutaneous microwave ablation of thyroid adneomas. The present system is comprehensive in that it is comprised of clinical observation, laboratory testing, focal ultrasonography and imaging guided biopsy. All these methods and modalities confirm the effectiveness and minor side-effect related to this percutaneous thermal therapy. We can conclude that this appraisal system is indispensable.