兔肝VX2瘤模型MR灌注成像与MVD及VEGF的相关性研究

Correlation of MR Perfusion Weighted Imaging with MVD and VEGF Expression in Rabbit Hepatic VX2 Carcinoma

目的研究肝脏肿瘤MR灌注成像(PWI)表现与微血管密度(MVD)、血管内皮生长因子(VEGF)的相关性,并优选灌注评价指标。材料与方法建立15只新西兰兔肝VX2瘤模型,随机分为A、B、C3组,每组5只,分别在肿瘤种植成功后的16、28、45天进行T2*WI的PWI和MVD、VEGF检测,PWI采用信号强度-时间曲线中的几个指标包括达峰时间(TTP)、最大信号下降百分率(SRRmax)、最大信号下降斜率(SRSmax)、平均通过时间(MTT)作为参数用于肿瘤灌注的定量研究,并分别与肿瘤的MVD计数、VEGF表达强度作直线相关分析。结果SRRmax、SRSmax与MVD呈正相关(r=0.584,P=0.022;r=0.731,P=0.002),其中SRSmax与MVD的相关性更高;3组之间SRSmax和MVD的总体差异均有统计学意义(F=6.352,P=0.013;χ2=9.260,P=0.010),A组的SRSmax、MVD明显高于C组(P<0.05);各项灌注指标与VEGF表达强度不相关。结论MR-PWI与MVD密切相关,SRSmax可作为优化的灌注评价指标。

Objective To investigate the correlation between MR perfusion weighted imaging （PWI） findings and mierovessel density （MVD） and vascular endothelial growth factor （VEGF） in hepatic neoplasm, and to optimize the parameter for evaluating PWI. Materials and Methods 15 New Zealand White rabbits with VX2 carcinoma were divided randomly into 3 groups （5 animals per group）. PWI using T2 ^＊ weighting and immunohistoehemieal staining of MVD and VEGF were performed on 16, 28, 45 days after tumor implantation in group A, B and C respectively, then the linear correlation analysis was used to determine the association between the PWI parameters, including time to peak （TTP）, maximal signal reduction ratio （SRRmax）, maximal signal reduction slope （SRSmax） and mean transit time （MTT） with the intensity of MVD and VEGF expression. Results SRRmax and SRSmax correlated positively with MVD （ r = 0. 584, P = 0. 022 ; r = 0.731, P = 0. 002）, and the correlation between SRSm~ and MVD was higher than that between SRRmax and MVD. The differences were significant in SRSmax （ F = 6. 352, P = 0. 013 ） and MVD （χ^2= 9.260, P = 0.010） of tumor boater in 3 groups of tumors, and there were significant differences between group A and group C （ P 〈 0.05 ）. There was no correlation between PWI parameters and VEGF expression. Conclusion The PWI findings correlate closely with MVD, and SRSmax may serve as the optimization parameter for evaluating PWI.