| Objective: To quantitate the parameters of DCE-MRI in rabbit VX2 malignant bone tumors before radiotherapy and 3,5,8 days after radiotherapy respectively,and the pathological index counting MVD and VEGF expression,and analyze their correlation to explore the value of DCE-MRI in reflecting the malignant bone tumor microvascular changes and the value of monitoring early radiotherapy effect.Methods: VX2 malignant bone tumor was implanted into the rabbit,and were randomly divided into 3 days,5 days,8 days radiotherapy group and 3 days,5 days,8 days control group.There are ten rabbits in each group.The radiotherapy group was treated with a single dose of 10 Gy radiation after 14 days.In 3-day radiotherapy group,DCE-MRI scans were performed on 1 day before radiotherapy and 3 days after radiotherapy.DCE-MRI scans were performed on 1 day before radiotherapy and 5 days after radiotherapy in 5-day radiotherapy group.DCE-MRI scans were performed on 1 day before radiotherapy and 8 days after radiotherapy in 8-day radiotherapy group.DCE-MRI scans were performed at the same time without radiotherapy in the control group.The tumor was taken out after completing the second examination,and the expression of MVD and VEGF were obtained.The quantitative parameters of tumor solid area and necrotic area were measured.According to the variations of quantitative parameters,the correlation between quantitative parameters and pathological indicators were analyzed.Results:(1)In the radiotherapy group,the Ktrans and Ve values of tumor solid area and necrotic area all decreased compared with before radiotherapy,and the difference was statistically significant.In the control group,the Ktrans values of tumor solid area increased compared with before radiotherapy,while the Ktrans values of tumor necrotic area decreased compared with before radiotherapy,and the difference was statistically significant.There was no statistically difference in Kep and Vp values in the radiotherapy group,and the statistically difference in Kep,Ve and Vp values in the control group was not significant at the same time before and after radiotherapy.(2)The Ktrans values of the tumor solid area and the necrotic area were gradually decreased in 3,5 and 8 days after the radiotherapy,respectively,and the Ktrans values of the tumor solid area were 0.1860±0.07,0.1154±0.07,0.0627±0.04,and the Ktrans values of the tumor necrotic area were 0.0463±0.07,0.0351±0.05,0.0283±0.03.All the difference above was statistically significant.The Kep,Ve and Vp values of the tumor solid area and the necrotic area in 3,5 and 8 days respectively after radiotherapy showed no statistical significance in the radiotherapy group.In the control group,the Ktrans,Ve values of the tumor solid area in 3,5 and 8 days respectively were statistically significant,while the Kep,Vp values of the tumor solid area and Kep,Ve and Vp values of the tumor necrotic area in 3,5 and 8 days respectively were not statistically significant.(3)In the radiotherapy group,the MVD values in the tumor solid area and the necrotic area decreased gradually in 3,5 and 8 days respectively after radiotherapy,the MVD values in the tumor solid areas were 27.00±5.33,22.42±6.42,15.04±7.58,in the tumor necrotic areas were 11.28±5.46,8.94±5.10,5.58±3.43,and the difference was statistically significant.The MVD values in the tumor solid areas and the necrotic areas changed without apparent pattern after 3,5 and 8 days respectively in the control group,and the difference was meaningless.In the radiotherapy group,the expression of VEGF in the tumor solid areas decreased gradually in 3,5 and 8 days after radiotherapy,the expression of VEGF values were 3.90±1.79,2.70±1.23,1.70±1.16 and the difference was statistically significant.The difference of tumor necrotic area was not statistically significant.In the control group,the expression of VEGF values in the tumor solid and necrotic areas showed no obvious pattern after 3,5 and 8 days,and the difference was not statistically significant.(4)After radiotherapy,Ktrans values of the tumor solid and necrotic areas was positively correlated with MVD count(r=0.816,r=0.742,r=0.746,r=0.803)and VEGF expression(r=0.694,r=0.705,r=0.816,r=0.803)in the radiotherapy group and the control group.After radiotherapy,there was no significant linear correlation between Kep,Ve,Vp and MVD,VEGF expression in each region of interest in the radiotherapy group and the control group.Conclusion: MVD and VEGF of the VX2 malignant bone tumor radiotherapy group 3,5,8 days gradually decreased,the control group's MVD and VEGF has no obvious regularity.As an important quantitative parameter of DCE-MRI scanning,Ktrans value was positively correlated with the MVD count and VEGF expression of VX2 malignant bone tumor,which can indicate the tumor microangiogenesis.Ve value can be used to evaluate the early efficacy after radiotherapy.It provides a theoretical basis for non-invasive examination method for clinical real-time evaluation of tumor status and therapeutic effect. |
PDF Full Text Request