Comparison Of The Ablation And Hyperechoic Zones In Different Tissues Using Microwave And Radiofrequency Ablation

Objective:To compare the differences of the ablation and hyperechoic zones during microwave versus radiofrequency ablation in porcine muscle and liver tissues with different powers.Methods:Fresh porcine muscle(outer ridge)and liver tissues with similar size were used as the materials of the ablation.The depth of the needle inserted into the specimen was about two thirds of the needle length.WB991029 RF therapy instrument and ECO-100C microwave therapy device were used to perform on porcine muscle and liver tissues respectively.The experimental materials were divided into 3 groups according to ablation power 15 W,30 W,45 W,each group had6 ablation lesions,and each tissue was ablated for 90s.The longitudinal diameter(Dl)and the thickness diameter(Dt)of the hyperechoic zones and the largest section of the lesion were measured,and the volumes were calculated,the experiment was repeated three times,total of 108 lesions of measurements were averaged.The differences between the hyperechoic range of the ablation zone were compared.Results:After ablated for 90s with different powers,the difference between the ablation range and the hyperechoic range D(D=ablation range-hyperechoic zones)was compared in muscle tissue.The D values ablated by microwave and radiofrequency ablation are as follows:15 W:(90.22±165.83)mm~3,(856.48±279.96)mm~3,30 W:(111.75±156.65)mm~3,(2737.10±1059.56)mm~3,45 W(-28.02±392.85)mm~3,(3172.27±1204.18))mm~3.For liver tissue ablation,microwave and radio frequency were used respectively.The D values were:15W:(255.34±102.08)mm~3,(361.20±285.39)mm~3,30W:(286.38±118.44)mm~3,(1847.62±519.11)mm~3,45W:(140.42±323.80)mm~3,(1963.98±945.52)mm~3.With the same power and duration,microwave and radiofrequency ablation were used to ablate porcine muscle tissue and liver tissue.The ablation range of the same tissue was significantly greater than that of hyperechoic zones(p<0.05),and the difference between the ablation range and the hyperechoic zone in microwave ablation was significantly less than radiofrequency ablation(p<0.05).Conclusion:Under the same conditions,when the ablation range is estimated using the hyperechoic zones in the ultrasound image,the hyperechoic zone observed may underestimate the ablation range,and the accuracy of the microwave ablation estimation may be higher than the radiofrequency ablation.