Comparison of shear wave elastography and quasi-static elastography in the evaluation of radiofrequency ablation:ex vivo experiment / 中华超声影像学杂志

ABSTRACT

Objective To investigate the value of shear wave elastography (SWE) and quasi-static elastography in the evaluation of radiofrequency ablation of pork.Methods Twelve pieces of fresh pork were underwent radiofrequency ablation (RFA) with different target temperatures.Before and after RFA,conventional ultrasound (US),SWE and quasi-static elastography were conducted to visualize the boundaries of RFA zones.The size of ablation zones obtained from conventional ultrasound,SWE and quasi-static elastography measurement were observed and detected the correlativity with pathology findings.Moreover,the Young's modulus and stain ratio of ablated zone were recorded.Results Most ablated boundaries were clearly delineated by both elastography techniques,except one with a low target temperature of 70 ℃.The sizes of ablated zones measured by SWE and quasi-static elastography were closely correlated with pathological findings.However,no ablated zones could be visualized by conventional US.Before and after RFA,the mean,minimum and maximum values of Young's modulus were (24.2 ± 3.8) kPa vs (97.6 ± 29.1) kPa,(9.2 ± 0.7)kPa vs (44.5 ± 7.7)kPa and (29.9 ± 3.8)kPa vs (181.5 ± 36.7)kPa,respectively (all P ＜0.001).With the increase of target temperature of RFA,the Young's modulus values and the mean strain ratio were significantly increased (all P ＜ 0.01).Conclusions Both SWE and quasi-static elastography are useful tools for evaluating the ablation,which are superior to conventional US.Moreover,SWE can be used to monitor the procedure of ablation.