Qualitative And Quantitative Study On Hepatocellular Residual Carcinoma Of Retrofit Model After RFA Therapy

ObjectiveTo establish an animal model like human' s remnant carcinoma of hepato-celluar carcinoma ( HCC) after RFA therapy, to evaluate the feasibility and the dependability of perfusion imaging for remnant carcinoma diagnosis by perfusion imaging of multisection CT (MSCT) , analysing perfusion parameters, comparing differences between remnant carcinoma and inflammatory reaction, dynamic observing hemodynamic changes of remnant carcinoma. To assess the practical significance of perfusion imaging on remnant carcinoma by comparing the mir-crovessel density ( MVD) and the cell proliferation parameters. To further investigate the clinical value of the quantitative assessment of MSCT about the remnant carcinoma of HCG after RFA therapy.Material and Method1. Set up 24 rabbits with VX2 carcinoma by injecting carcinoma tissues percutaneous and inoculating carcinoma tissues open - abdomen respectively. 12 rabbits each group, within 14 days after inoculation, all rabbits underwent CT plain scan,contrast scan and pathohistology to evaluate achievement ratio of inoculation and the growth status.2. To set up 48 rabbits with VX2 carcinoma successfully by ultrasonic guidance percutaneous puncture injecting carcinoma tissues,underwent RFA therapy and reserve part of the carcinoma after RFA, then the animal models of remnant carcinoma were estalished. Rabbits were divided 6 groups, 8 in each. Each group will be evaluated by CT scan and perfusion CT during the course of pre -RFA and the post -RFA (ld^3d^lwA2wA3w) respectively. After imaging evaluation, they will be killed and observed in pathology.3. To acquire the imaging of CT plain scan and contrast scan of remnant carcinoma and inflammatory reaction, comparing the differences in CT value, i-dentifying the remnant carcinoma at different time by single blind method.4. To get the perfusion parameters that calculated by perfusion 3 liver perfusion software of GE company: BF^BV^MTT^PSAHAF. Comparing the differences of perfusion parameters between remnant and inflammatory reaction, dynamic observing hemodynamic changes of remnant carcinomas.5. All the 48 rabbit - models were killed after RFA and their tissues (including remnant carcinomas and inflammatory tissues) were embedded in paraffin, fixed in 10% Formalinand spitted constantly with 5jxm - section. The enhanced border of tumors were examed pathologically with HE dying and determinated CDSl^VEGF^PCNA with immunohistochemistry. Then the results of im-munohistochemistry and perfusion parameters were compared.6. Statistical analysis: All the data were analysed by SPSS software. Quantitative data were showed by x ± s, P < 0.05 was defined as threshold for statistical significance and P <0.01 was very statistical significance.Result1. The survive rate of the rabbits inoculated VX2 tumor cells were 91.7% , there were no differences betweeen percutaneous and open - abdomen. There were 5/11 cases infected in open - abdomen group, but none in percutaneous group. The carcinomas showed sublobiform 9/11 in percutaneous group, but 3/ 11 in the other group (P <0.05). There was necrosis appearing in the carcinomas 8/11 in open - abdomen group, but 3/11 in percutaneous group ( P < 0.05 ). But there was no significant differences in diameters of carcinomas ( P > 0.05).2. The achievement ratio of remnant carcinoma after RFA was 100%. The inflammatory band existed in all the cases(8 cases) lw after RFA, rare(2 cases) in 2w and all disappeared in 3w. The inflammatory reaction reached itspeak at 3 days after RFA, the pathology showed acute inflammatory reaction and effusion in most, the inflammatory gradually disappeared during 3d — 2w and fi-brosis in most, there was no significant differences in CT value between inflammatory and remnant carcinoma in lw, but significant differences in 2w. Hie accuracy and specificity of CT diagnosis were all 25% in lw after RFA , and the accuracy and specificity of CT diagnosis were all 100% in 2w after RFA.3. The BF?PS were more sensitive than others in CT perfusion parameters. At different time, BF of remnant carcinoma was bigger than that of inflammatory ( P < 0.05 );PS of remnant carcinoma was bigger than that of inflammatory ( P < 0.01). Hie change tendence of PS in remnant carcinoma and inflammatorywere the same to BF.4. The change of CT perfusion parameters with time: BF^BV and PS all increased in 3d after RFA, gradually decreased in 3d -2w, and increased again in 2w - 3w. But the parameters in different group were not completely the same. There were significant differences in BF between each two groups except pre -RFA and lw^3w group, Id and lw group, lw and 3w group(P<0.05). There were significant differences in BV only between pre — RFA and 3d group, 2w and ld^d^lw^w group(P <0.05). There were significant differences in MTT only between 2w and pre - RFANld^3dNlw group,3w and ld^3d group(P < 0.05 ). There were significant differences in PS between each two groups except 3w and pre - RFAN2w group, Id and 3d^lw^2w group, lw and 3dN2w group(P<0.05).5. The express of MVD.VEGF and PCNA decreased after RFA and lasted low level until 2w after RFA, then increased again in 2w — 3w after RFA.6. The CT perfusion parameters were positive correlated to the express of MVD^VEGF and PCNA in 3w after RFA group. The express of MVD^VEGF and PCNA were all positive correlation at different times.Conclusion1. The animal models of VX2 tumors by percutaneous puncture injecting carcinoma tissues were easily copied, high achievement ratio, little damaged toanimal and low rate of tumor necrosis, which were suitable for the study of HCC s therapy.2. The remnant carcinomas after RFA were alike the humans'and easily copied, so it provided ideal animal models for the study of imageology, remnant carcinomas' quantitation and qualitation, therapeutic effect assessment and post- continue therapy of HCC.3. Pathology study after RFA: the CT band of post - RFA was inflammatory reaction band, This band appeared immediately after RFA and reached its peak in 3d, existed rare in 2w and disappeared completely in 3w. To diagnosis the exist of coagulation necrosis by HE dying was difficult, but immunohistochemis-try was easy and exact.4. It was hard to identify remnant carcinoma and inflammatory reaction in lw after RFA by CT constrast scan, but could be identified after 2w.5. CT perfusion scan provided several parameters that including BF and PS, which were helpful to identify remnant carcinomas and inflammatory reactions.6. There was significant correlation between carcinoma angiogenesis and MVD^VEGF. PCNA showed the express of carcinomas proliferation. PCNA was positive correlated to MVD and VEGF, the carcinoma angiogenesis interacted with carcinoma cells.7. Perfusion parameters - time curve dynamic showed the blood supply of carcinoma which had great significances to post - continue therapy of HCC.8. The remnant tissues of the rabbit liver VX2 carcinomas showed inhibitory status in 2 weeks. At this time, the proliferation rate of carcinoma angiogenesis and carcinoma proliferation were all low. In the 3rd week the proliferation rate of carcinoma angiogenesis and carcinoma cells all became high, which indicated that the growth of carcinoma could be inhibited by RFA in short term but developed again and needed further therapy during the following time.