| Objective By dynamic contrast enhanced magnetic resonance imaging and pathological study of experimental study,we investigate the correlation between DCE-MRI quantitative parameters and microvessel density change before and after rabbit VX2 malignant bone tumor chemotherapy to provide a diagnostic basis for the early treatment of malignant bone tumor after chemotherapy.Methods The establishment of rabbit VX2 malignant bone tumor models were randomly divided into control group and experimental group with 15 rats in each group(In the experimental group,the chemotherapy drug was cisplatin,and the dosage was 7mg/kg.The control group was injected with 0.9% saline,the same dose as the experimental group).DCE-MR scanning was performed before treatment and after three days of treatment.Then,we quantitatively analyze the obtained images through the hemodynamic two-compartment model.The hemodynamic parameters of tumor solid components and tumor center necrotic region were obtained: volume transfer coefficient(Ktrans),rate constant(kep),extravascular extracellular space volume(Ve),and volume fraction of intravascular contrast agent(Vp).Compared with routine pathology and immunohistochemistry,the distribution of MVD in different regions of tumor was investigated.Finally,the SPSS22.0 statistical software was used to analyze the correlation between the parameters of DCE-MRI and the results of immunohistochemistry.Results(1)Comparison of DCE-MRI quantitative analysis parameters before and after treatment in different regions of the experimental group and control group.The Ktrans value,Kep value,Ve value and Vp value of tumor solid components in the experimental group before and after chemotherapy were respectively:(0.5017±0.60)and(0.0549±0.03)min-1(P=0.011),(1.3723±0.63)and(0.6398±0.38)min-1(P=0.000),(0.1098±0.08)and(0.2463±0.17)min-1(P=0.007),(0.1371±0.05)and(0.1276±0.05)min-1(P=0.062).The Ktrans value,Kep value,Ve value and Vp value of tumor solid components in the control group before and after the treatment were respectively:(0.3260±0.21)and(0.6596±0.11)min-1(P=0.000),(0.6862±0.51)and(1.0617±0.45)min-1(P=0.001),(0.1699±0.06)and(0.0892±0.06)min-1(P=0.000),(0.1182±0.05)and(0.1310±0.06)min-1(P=0.090).The Ktrans value,Kep value,Ve value and Vp value of the tumor center necrotic region in the experimental group before and after chemotherapy were respectively:(0.1403±0.17)and(0.0071±0.01)min-1(P=0.007),(0.7469±0.29)and(0.1046±0.09)min-1(P=0.000),(0.0396±0.01)and(0.0576±0.01)min-1(P=0.000),(0.0821±0.03)and(0.0743±0.04)min-1(P=0.314).The Ktrans value,Kep value,Ve value and Vp value of the tumor center necrotic region in the control group before and after treatment in the control group were respectively:(0.0341±0.05)and(0.2478±0.25)min-1(P=0.002),(0.1447±0.12)and(0.5404±0.32)min-1(P=0.000),(0.0404±0.01)and(0.0315±0.01)min-1(P=0.000),(0.0702±0.04)and(0.0782±0.04)min-1(P=0.096).The difference of Ktrans value,Kep value and Ve value between the control group and the experimental group was statistically significant(P < 0.05),and the Vp value was not statistically significant(P > 0.05).(2)The contrast results of MVD in the experimental group and the control group after the treatment in different regions: in experimental group and control group,the MVD of solid tumor and necrotic area in the two groups after treatment were(28.89+ 3.11)and(45.16+6.52)(P=0.000),(16.83+1.71)and(23.27+2.67)(P=0.000),respectively,and the difference between them was statistically significant(P < 0.05).(3)The correlation analysis between the quantitative analysis parameters of DCE-MRI and the correlation of MVD in the experimental group and the control group after the treatment of different regions: the MVD value of tumor solid region in the experimental group and the control group was positively correlated with the value of Ktrans and the value of Kep(experimental group rktrans=0.946,rkep=0.875;control group rktrans=0.942,rkep=0.894.P < 0.05),and had no significant correlation with the value of Ve and the value of Vp(experimental group r Ve=0.122,r Vp=0.479;control group r Ve=0.201,r Vp=0.375.P > 0.05).The MVD value of the tumor center necrotic region in the experimental group and the control group was positively correlated with the value of Ktrans and the value of Kep(experimental group rktrans= 0.926,rkep=0.869,rktrans=0.963,rkep=0.810 control group,P < 0.05),and had no significant correlation with the value of Ve and the value of Vp(experimental group r Ve=0.380,r Vp=0.348;control group r Ve=0.333,r Vp=0.367.P > 0.05).Conclusion DCE-MRI quantitative analysis parameters Ktrans value and kep value have a significant positive correlation with tumor microvessel density.It can be used to predict the changes of microvessel in tumor timely and accurately after chemotherapy,so as to evaluate the early efficacy of chemotherapy after chemotherapy. |
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