The Reliability Research In Ultrasound Temperature Imaging And Elastography In Radiofrequency Ablation

Radiofrequency ablation (RFA) which is induced by heat tissue coagulationnecrosis achieves the goal of treatment of tumors. It has been considered to be a safeand effective minimally invasive treatment method. Successful ablation depends onthe temperature change of radiofrequency ablation zone. Ultrasonic imaging iscurrently the most commonly used in medical monitoring. The purpose of this study isto explore the applicability about the temperature and elasticity imaging method underdifferent power, which gives some reference to future clinical research.In this study, prepare some liver samples for ablation under different power (10w,50w).The heating time was3minutes. The RF ablation process was monitored by adiagnostic ultrasound imager and the information was postoperatively captured forfurther temperature and elasticity image analysis. The infrared thermometry wasconcurrently applied to provide temperature change calibration during the RFA.Results from this study demonstrated that the echo shift imaging is valid under10W RF exposure, but the ablation zone is no longer consistent with the referenceunder the high RF exposure. The elasticity change could well reflect the ablation zoneunder50W exposure; in the contrary, under low exposure, the thermal lesion cannotbe well detected due to the limited range of temperature elevation and incompletetissue necrosis. The temperature imaging based on the changes in the backscatteredenergy showed good consistency no matter what the power was. It has better stabilitythan echo-shift image and has no limits as the elasticity imaging which is only suitedunder high power. It can be a reliable tool to describe the temperature profile duringradiofrequency ablation.This is the first time to discuss the reliability among the three methods. We havedemonstrated that the diagnostic-ultrasound based temperature and elastography isvalid for the monitoring of RF ablation process. The temperature estimation based onthe echo shifts can well reflect mild-power RF ablation dynamics, the other algorithmbased on the CBE has good applicability in high and low power. Whereas theelastic-change estimation can well predict the tissue necrosis. This study providesadvances towards using diagnostic ultrasound to monitor RFA or other thermal-basedinterventions through the three methods.