| Background and purpose Glioma hypoxia increases the risk of malignant progression and recurrence and resists to radiotherapy and chemotherapy.Therefore,the assessment of tumor hypoxia can help determine the degree of malignancy and prognosis of patients.In the past,the methods used to detect tumor hypoxia are invasive,radiative,and can not detect the oxygen status in tumor dynamicly.Therefore,we need a dynamic,repeated,noninvasive method to detect the tumor hypoxia state.Dynamic contrast enhanced MRI(DCE-MRI)quantitative scanning can help obtain tumor blood flow,and vascular permeability,which could be used to evaluate the tumor microenvironment.IVIM-DWI can be used to measure the diffusion and perfusion of water molecules in vivo,and which can also be used to evaluate the microenvironment in the molecular level without the use of contrast agents.The biological marker of hypoxia mainly include hypoxia inducible factor(hypoxia-inducible factor-1 alpha,HIF-1 alpha),vascular endothelial growth factor(vascular endothelial growth,VEGF)and so on.In this study,a correlative study was done between the expression of HIF-1? and quntitaive parameters of DCE-MRI and IVIM-DWI to explore the feasibility of a ombination of DCE-MRI with IVIM-DWI in the evaluation of the status of hypoxia.Materials and methods Fifty two SD rats,male,clean grade,250-300 g were used.C6 glioma cells collected in logarithmic growth period,and C6 brain glioma model was established.IVIM-DWI and DCE-MRI scanning were performed 2W,3W,4W after tumor implantation and postprocessing was used to acquire the pseudocolor maps and quantitative parameters.HE staining and HIF-1? immunohistochemical staining were performed in 14 SD rats after each scan,and the correlation between IVIM-DWI and DCE-MRI quantitative parameters and HIF-1 expression was statistically analyzed.Result In model group at 2W,3W,4W after implantation,Ktrans value were 0.097±0.065,0.194±0.094,0.134±0.069,Ve value were 1.041±0.434,0.759±0.337,0.385±0.245,ADCstandard value were 4.138±0.291,3.075±0.363,2.296±0.366;D value were 5.156±0.457,4.545±0.402,2.620±0.454;D* value were 10.014±0.613,6.708±0.596,4.025±0.504;f value were 9.194±0.441 7.770±0.487,6.389±0.524;HIF-1? score were 2.0±0.961,6.5±3.653,4.071±2.129;At the time of 3W,4W after tumor implantation,Ktrans,Ve and IVIM-DWI quantitative parameters were negatively correlated with HIF-1 expression(the correlation coefficient at 3W,Ktrans: ?=-0.825,Ve: ?=-0.818,ADCstandard:?=-0.954;D:?=-0.965;D*:?=-0.979;f:?=-0.987;and the correlation coefficient at 4W,Ktrans: ?=-0725;Ve: ?=-0.607,;ADCstandard:?=-0.783;D:?=-0.764;D*:?=-0.716;f:?=-0.725;P value were<0.05).there was no significant correlation between Ktrans,Ve and HIF-1 expression at time of 2W glioma model(p>0.05),and there was no significant correlation between Kep and HIF-1 expression in all timepoint.Conclusion It is feasible for DCE-MRI and IVIM-DWI to be used to evaluate the hypoxia status of in experimental C6 glioma dynamicly.The correlation between DCE-MRI,IVIM-DWI quantitative parameters and tumor hypoxia state was different in different growth stages of tumor. |
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