Research On The New Ultrasound Real-time Quantitative Monitoring Methods Of Microwave Ablation For Liver Tumor

The ablation needle is inserted directly into the tumor tissue during liver tumor microwave ablation,and continuously releases microwave energy to heat the tumor tissue to above 60°C.The tissue undergoes thermal coagulation,dehydration,and necrosis,thus killing cancer cells.Microwave ablation has advantages of minimal invasion,short operation time,and easy operation.However,lack of a quantitative and real-time monitoring method limits the wider use of microwave ablation in the clinic.At present,the microwave ablation monitoring techniques in the clinic include: ultrasound imaging(USI),computed tomography(CT),magnetic resonance imaging(MRI),and nuclear medicine imaging(NMI).CT has ionizing radiation,so it is not suitable for long-term monitoring;MRI is not good in temporal resolution;NMI equipment are not widely used in the clinic because of its high price.USI has attracted widespread attention due to its good real-time performance and low cost.In this study,several methods for monitoring microwave thermal ablation based on quantitative ultrasound were explored,mainly including:1.The method of detecting microwave thermal coagulation based on ultrasound echo decorrelation imaging.An algorithm of the ultrasound echo decorrelation coefficient extraction was implemented,and the ultrasound echo decorrelation coefficient was proved to be useful for detecting microwave thermal coagulation.Fifteen cases of ex vitro pig liver microwave ablation experiments(P=80w?t=60s)were performed,and the actual coagulation zone of the pig liver tissue gross pathology was considered to be the gold standard.Statistical analysis showed that the average accuracy of the microwave thermal coagulation detection based on ultrasound echo decorrelation imaging was 88.60%.2.The method of detecting microwave thermal coagulation based on scatterer characteristic parameter imaging.Two ultrasound parameters were extracted: mean scatterer spacing and effective acoustic concentration.it was proved that the effective acoustic concentration was capable for detecting microwave thermal coagulation.Fifteen cases of ex vitro pig liver microwave ablation experiments(5 cases of P=50w?t=120s,10 cases of P=80w?t=60s)were performed,and the actual coagulation zone of the pig liver tissue gross pathology was considered to be the gold standard.Statistical analysis showed that the average accuracy of the microwave thermal coagulation detection based on effective acoustic concentration imaging was 92.48%(P =50w?t=120s)and 81.37%(P =80w?t=60s).The total average accuracy was 84.84%.3.The method of detecting microwave thermal coagulation based on ultrasound attenuation imaging.An algorithm of ultrasound attenuation coefficient extraction was implemented,and the ultrasound attenuation coefficient was proved to be useful for detecting microwave thermal coagulation.Fifteen cases of ex vitro pig liver microwave ablation experiments(P=80w?t=60s)were performed,and the actual coagulation zone of the pig liver tissue gross pathology was considered to be the gold standard.Statistical analysis showed that the average accuracy of the microwave thermal coagulation detection based on ultrasound attenuation coefficient imaging was 90.09%.