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(P【0.01).There was a positive correlation between MVD and VEGF in the border(P【0.05).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(P【0.05),HPP was negatively correlated with MVD and VEGF(P【0.01),and HBV and MTT values were not correlated with MVD and VEGF(P】0.05).CONCLUSIONS:Significant correlations were found between perfusion parameters and MVD and VEGF.Therefore,MSCTP can be used to evaluate tumor angiogenesis in vivo.

Functional CT for assessment of early vascular physiology in liver tumors

BACKGROUND: CT perfusion has been reported to have great advantages in detecting hepatic diseases. However, currently there are no studies showing the potential value of multi-slice CT perfusion with the deconvolution model method in diagnosing early hemodynamic changes caused by liver tumors. This study was undertaken to determine if early hemodynamic changes caused by liver tumors can be depicted with the perfusion imaging of multi-slice CT. METHODS: Ten New Zealand white rabbits before and after VX2 liver tumor inoculation served as the experimental animals. Ten normal rabbits served as controls. All underwent multi-slice CT perfusion for the measurement of hepatic blood flow (HBF), hepatic blood volume (HBV), mean transit time (MTT), permeability of capillary vessel surface (PS) and hepatic artery index (HAI). RESULTS: With the exception of MTT, which decreased significantly at the tumor periphery, HBF, HBV,. PS and HAI increased significantly compared with the surrounding normal tissue. All these changes occurred at days 5-9 after tumor inoculation. Statistically significant changes in these values were detected with tumor growth. CONCLUSIONS: The hemodynamic changes in the liver caused by rabbit VX2 liver tumor can be detected after tumor inoculation, and functional CT can evaluate the physiological characteristics of early tumor angiogenesis.