Preliminary Study on Antiangiogenic Treatment Effect in Rat Liver Metastasis Using Quantitative Parameters of Two-dimensional Shear Wave Elastography
Objective:To study value of two-dimensional shear wave elastography(SWE)in the evaluation of antiangiogenic treat-ment effect of single colon cancer metastasis in liver of nude rat.Methods:Sixteen nude rats with colon cancer liver single metastasis were divided randomly into treatment group and control group.The treatment group was treated with Ramucirumab(8 mg/kg,tail vein injection)on Day 0,Day 4,Day 7 and Day 11 respectively,while the control group was injected with the same dose of saline.The tumor size and volume were measured before treatment(Day 0)and after 14 days of treatment(Day 14).On Day 14,to evaluate the stiffness of tumor and surrounding liver tissue,the liver tumor and surrounding liver tissue SWE examination were performed and the elastic parame-ters(including Vs-tumor,Vs-liver,E-tumor and E-liver)were measured and then the R-Vs(=Vs-tumor/Vs-liver)and R-E(=E-tu-mor/E-liver)were calculated respectively.Finally,expression of matrix metalloproteinase 2(MMP2)and transforming growth factor β2(TGF β2)in tumors were detected by immunofluorescence staining.Results:There was no significant difference in the tumor size be-tween the treatment group and the control group both on Day 0 and Day 14(P>0.05).Vs-liver and E-liver had no significant difference between the treatment group and the control group(P>0.05).Both Vs-tumor and E-tumor in treatment group were mildly higher than those in the control group,however,these differences were not statistically significant(P>0.05).In the treatment group,both R-Vs and R-E were significantly higher than those in the control group(P<0.05).The expression levels of MMP2 and TGFβ2 were significantly higher than those in control group respectively(P<0.05).Conclusions:The quantitative parameters of SWE may have the potential as an image biomarker indicating tumor stiffness for evaluating the anti-angiogenic therapy efficacy.