剪切波弹性成像评价离体猪肝组织射频消融灶的实验研究

Shear wave elastography in the evaluation of porcine liver treated with radiofrequency ablation：an in vitro experiment

目的探讨剪切波弹性成像（shearwaveelastography，SWE）评价不同消融条件下离体猪肝组织射频消融（radiofrequencyablation，RFA）灶硬度变化和消融气体对弹性成像的影响。方法新鲜离体猪肝12只共24块，随机分为4组，每组6块。分别予以RFA6mira、12rain、无水酒精15ml注射联合RFA6min、无水酒精15ml注射联合RFA12rain，测定并比较消融前、消融后气体未消除时、消融后气体消除时猪肝消融区杨氏模量。结果SWE图清晰显示消融区域硬度变化范围，且二维声像图中强回声气体后方声衰减部分得到显示。消融前、消融后气体未消除时、消融后气体消除时的杨氏模量分别为（14．90±4．04）kPa、（94．31±23．03）kPa、（89．32±20．77）kPa，消融后气体未消除时、消融后气体消除时杨氏模量分别与消融前杨氏模量比较差异具有统计学意义（P〈0．001、P〈0．001），消融后气体未消除时杨氏模量与消融后气体消除时杨氏模量比较差异无统计学意义（P=0．385）。RFA6min、12min、无水酒精15ml注射联合RFA6min、无水酒精15ml注射联合RFA12min消融前后杨氏模量改变分别为（81．29±9．19）kPa、（84．88±9．89）kPa、（97．27±16．20）kPa、（103．82±22．04）kPa，是否联合元水酒精注射对射频消融前后杨氏模量变化影响差异具有统计学意义（P=0．009），而射频消融持续时间的不同对消融前后杨氏模量变化影响差异无统计学意义（P=0．275）。结论SWE几乎能够不受气体影响定量分析离体猪肝射频消融灶硬度变化，且不同消融条件的杨氏模量变化有所不同。

Objective To evaluate the stiffness of porcine liver in vitro treated with the radiofrequency ablation （RFA） using shear wave elastography （SWE）. Methods A total number of 24 pieces of porcine livers were randomly divided into 4 groups,which were treated with RFA for 6 min or 12 min,and 15 ml ethanol injection combined with RFA for 6 min or 12 rain,respectively. The Young modulus were measured before ablation, after ablation immediately and 30 rain after ablation when the gas disappeared in ablation zone. Results SWE imaging can clearly delineate the boundary of the stiffness changes in the RFA ablation zone, even that part was difficult to display in baseline ultrasound due to the gas hyperechogenicity reflection. The mean Young modulus before ablation, after ablation immediately and 30 min after ablation without gas reflection were （14.90 ± 4.04） kPa, （94.31± 23.03） kPa, （89.32 ± 20.77） kPa,respeetively. Both the mean Young modulus of after ablation immediately and 30 min after ablation were significantly different from that of before ablation （ P 〈0. 001, P 〈 0. 001 ）, but there was no significant difference between the mean Young modulus of after ablation immediately and 30 min after ablation （ P = 0. 385）. The Young modulus changes of ablation zone of RFA 6 min, 12 min, 15 ml ethanol injection combined with RFA 6 min or 12 min were （81.29 ± 9.19） kPa, （84.88 ±9.89） kPa, （97.27± 16.20）kPa, （ 103.82 ± 22.04） kPa, respectively. The ethanol injection combined with RFA could make the ablation zone stiffer than only RFA did （ P = 0. 009） ,whereas prolonging ablation duration would make nochange of stiffness in ablation zone （P = 0. 275 ）. Conclusions SWE can quantitatively monitor the elasticity changes of porcine liver during RFA treatment in vitro, no matter the gas exists in the ablation zone or not. The changes of stiffness in ablation zone were different when ethanol was injected pre-ablation.