Experimental study on early effects of bevacizumab evaluated by dynamic enhanced magnetic resonance imaging / 中华消化杂志

ABSTRACT

Objective To explore the feasibility and value of dynamic contrast-enhanced (DCE-MRI) parameters in assessing early effects of anti-angiogenesis medicine in targeted therapy for tumors.Methods Twenty BALB/C-nu nude mice were injected subcutaneously with human colon cancer cells HT-29 to the right hind leg.The nude mice were evenly divided into the experimental group and control group with 10 mice in each group.The mice of experimental group were intraperitoneally injected with bevacizumab,and the control group were injected with the same volume of saline.DCE-MRI was performed before medication and one hour,24 h and 48 h after medication.The Ktrans,Kep,Ve and initial area under enhancement curve (iAUC) of DCE-MRI were analyzed.The animals were sacrificed 48 hours after medication.Microvessel density (MVD) of the tumors was detected by immunohistochemistry.One way analysis of variance was performed to analyze parameters of DCE-MRI.The Pearson correlation coefficient was used to analyze the correlation between parameters of DCE-MRI and MVD.Results Under DCE-MRI,the edge of subcutaneous colon cancer xenografts was obviously gradually enhanced,pseudo color indicated high perfusion,the strength degree of the central region was low and which meant low perfusion.The differences in Kep of different time point of experimental group were statistically significant (F=3.752,P=0.016) ; there as no significant difference in other parameters of DCE MRI (all P＞0.05).There was no significant difference in Ktrans and Kep before medication and one hour after medication (all P＞0.05).There were significant difference in Ktrans and Kep 24 hour and 48 hour after medication between experimental group (24 hour∶ (0.095 ± 0.039) min-1 and (0.297 ± 0.141) min-1,48 hour∶ (0.090±0.033) min 1 and (0.314±0.148) min-1) and control group (24 hour∶ (0.150±0.074) nin-1 and (0.494±0.126) min-1,48 hour∶ (0.171±0.045) min-1 and (0.441± 0.092) min-1) (F24h =4.824 and 11.386,F48h =22.605 and 5.455,all P＜0.05).There was no significant difference in Ve and iAUC between two groups at different time points (all P＜0.05).MVD of experimental group was lower than that of control group.Ktrans and Kep were positively correlated with MVD (r=0.745 and 0.400,both P＜0.05).Conclusion Ktrans and Kep parameters of DCE-MRI may be used in monitoring the earlier effects of anti-angiogenesis medicine in targeted therapy for colon cancer.