Quantification of angiogenesis by CT perfusion imaging in liver tumor of rabbit

BACKGROUND:Tumor angiogenesis is essential for primary and metastatic tumor growth.Computed tomography perfusion(CTP)is a new imaging method,made possible by the recent development of fast CT scanners and improved data analysis techniques,which allows measurement of the physiologic and hemodynamic properties of tissue vasculature.This study aimed to evaluate CTP in the quantification of angiogenesis and to assess the relationship between tissue perfusion parameters and microvascular density(MVD)and vascular endothelial growth factor(VEGF),attempting to detect the physiologic properties of angiogenesis.METHODS:Sixteen rabbits with VX2 liver tumors underwent multi-slice CT perfusion(MSCTP)on day 14 after tumor inoculation.CTP parameters included hepatic blood flow(HBF),hepatic blood volume(HBV),mean transit time(MTT),permeability of capillary vessel surface(PS),hepatic artery index(HAI),hepatic artery perfusion(HAP),and hepatic portal perfusion(HPP).The border of the tumor was stained with CD34 and VEGF immunohistochemical stains,and MVD was measured by anti-CD34.Then,CTP parameters were determined whether they were correlated with MVD and VEGF using Pearson's correlation coefficient.RESULTS:The positive expression of MVD was different in the center and border of the tumor(P0.01).There was a positive correlation between MVD and VEGF in the border(P0.05).As more VEGF was expressed,the number of microvessels increased.Correlation analyses were also made between the perfusion parameters and MVD and VEGF in the border of the tumor.HBF,PS,HAI,and HAP values were positively correlated with MVD and VEGF(P0.05),HPP was negatively correlated with MVD and VEGF(P0.01),and HBV and MTT values were not correlated with MVD and VEGF(P0.05).CONCLUSIONS:Significant correlations were found between perfusion parameters and MVD and VEGF.Therefore,MSCTP can be used to evaluate tumor angiogenesis in vivo.