剪切波弹性成像对比准静态弹性成像评价射频消融效果的离体实验研究

Comparison of shear wave elastography and quasi-static elastography in the evaluation of radiofrequencyablation：ex vivo experiment

目的探讨剪切波弹性成像对比准静态弹性成像在评价离体猪肉组织射频消融效果中的应用价值。方法选取12块新鲜的离体猪肉组织，进行不同靶温度的射频消融，剪切波弹性成像（SWE）监测消融过程。消融结束后，分别应用普通超声、SWE和准静态弹性成像观察消融灶的大小，以大体标本的测量值为标准，并测量消融前后猪肉组织的杨氏模量值及应变率比值的变化。结果除1个靶温度为70℃的消融灶外，11个消融灶的边界能被SWE及准静态弹性成像清晰显示，所测量的消融灶大小与大体标本有很好的相关性；而普通超声不能显示消融灶的边界。消融前后猪肉组织的杨氏模量平均值、最小值和最大值分别为（24．2±3．8）kPa对（97．6±29．1）kPa、（9．2±0．7）kPa对（44．5±7．7）kPa和（29．9±3．8）kPa对（181．5±36．7）kPa，差异均有统计学意义（均P〈0．001）。随着消融靶温度的增加，消融灶的杨氏模量和应变率比值均增加（均P〈0．01）。结论SWE和准静态弹性成像均为评价射频消融效果的有效方法，优于普通超声；SWE还能应用于消融过程的监测。

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.