PET/CT及超声造影对兔VX2肉瘤射频疗效评估的实验研究

Evaluating therapeutic effects of radiofrequency ablation on rabbit VX2 tumors using PET/ CT and contrast-enhanced ultrasound.

目的本研究采用PET/CT成像及增强超声(CEUS)观察兔VX2肉瘤射频消融术后表现,明确其敏感性、特异性等。方法新西兰大白兔载瘤兔9只,随机分为射频消融治疗组(n=7)和对照组(n=2)。动物肿瘤模型制作后14 d行射频治疗,治疗前、治疗后2 d和14 d进行PET/CT和CEUS检查。治疗后1个月处死行病理、免疫组化染色及电镜观察。结果动物模型的成功率为100﹪,消融均获成功,PET/CT和CEUS的显像成功率均为100﹪。免疫组化结果、HE染色结果及电镜结果相符合。PET/CT+CEUS敏感性为92.2﹪,高于CEUS(87.3﹪,P<0.05)及PET/CT(84.2﹪,P<0.05),特异性90.7﹪,高于CEUS(76.5﹪,P<0.05)及PET/CT(86.6﹪,P<0.05)。PET/CT敏感性与CEUS无显著差异(P>0.05),PET/CT特异性高于CEUS(P<0.05)。结论 PET/CT及CEUS监测射频消融疗效安全有效,PET/CT及CEUS互有优势,二者联合可显著增加残瘤检出率。

Objective This study combined fluorine-18-deoxyglucose （FDG） PET/CT and contrast- enhanced ultrasound （CEUS） to acquire images and data prior and subsequem to radiofrequency ablation （RFA） to observe representation in rabbit VX2 tumors. In this study, we acquire images and data prior and subsequent to radiofrequency ablation （RFA） using PET/CT combined with CEUS so as to evaluate sensitivity and specifity of the combination of PET/CT and CEUS in assessing the response to RFA. Methods Nine New Zealand rabbits with VX2 tumors in hind limbs were randomly divided into two groups. A treatment group （n = 7） underwent RF ablation while rabbits that did not receive RFA constituted a control group （n = 2）. RFA was performed 14 days after VX2 implantation. 18F-FDG PET/CT and CEUS examinations were performed in each groups 2 days before and after RF ablation, and 14 days after RF ablation.Tissue samples were observed using transmission electron microcopy and pathologic examination. Expression of CD31, MMP-9, VEGF in tumor tissues were also inspected. Results The immune-histochemieal results were consistent with gross pathological and transmission electron microscopy observation.The sensitivity of CEUS is 87.3 % and specificity is 76.5 % .The sensitivity of PET/CT is 84.2 % and specificity is 86.3 % .The sensitivity （92.2 % ） and specificity （90.7 % ） of combination CEUS ＋ PET/CTis significantly higher than both PET/CT and CEUS group （P 〈 0.05）. Conclusion ISF-FDG PET/CT and CEUS is useful in the assessment of RFA therapeutic response and completeness, PET/CT and CEUS possess their own advantages,and the combination of them can increase the detection rate of residual tumor.