Intravoxel Incoherent Motion Diffusion Weighted Imaging Of High-grade Gliomas And Brain Metastases: Efficacy In Preoperative Differentiation In The Parenchyma And Peritumoral Edema Regions

Objective To investigate the value of intravoxel incoherent motion diffusion weighted imaging(IVIM-DWI)in the parenchyma and peritumoral edema regions of high-grade gliomas and brain metastases,and the differential diagnosis of the two tumors.Methods The conventional MRI,contrast-enhanced MRI and IVIM-DWI were performed before any treatment in 24 patients with high-grade gliomas and 28 cases with brain metastases who were confirmed by pathological examination.There were 13 b values between 20-1500s/mm2 of IVIM-DWI for scanning.The regions of interest(ROI)according to the conventional MRI images were selected and the diffusion constant D values,the pseudodiffusion coefficient of perfusion D* values and the perfusion fraction f in the parenchyma and peritumoral edema region within 1cm and the normal centrum semiovale in the opposite side were measured,and then the relative values of all parameters in each region were calculated.Independent sample t test was used to statistical analysis of the parameters in the three selected regions between the two tumors.Receive operating characteristic(ROC)curve analysis of the parameters which were different with statistically significant between the high-grade gliomas and brain metastases,and the best threshold was determined and the sensitivity,specificity and the area under the curve were calculated,and the diagnostic efficacy was evaluated.Paired t tests were used to analyze the differences of the parameters between the three selected regions in every tumor groups.Results The D* and rD* value of high-grade gliomas in tumor parenchyma and in peritumoral edema within 1 cm were higher than those of brain metastases(all P<0.05).The f and rf value of high-grade gliomas in tumor parenchyma and in peritumoral edema within 1 cm were lower than those of brain metastases(all P<0.05).ROC curves showed the parameters with statistical significance were valuable to a certain extent in the clinical diagnoses because they were all larger than 0.7,and the D* values in the peritumoral edema(AUC=0.910,P<0.001,sensitivity 100%,uniqueness 100%)was highest,but there was not statistically different between them except the r D* value of peritumoral edema within 1 cm.There was not statistically different of D and r D values in the tumor parenchyma and peritumoral edema(within 1 cm)and D,D*,f values of the normal centrum semiovale in the opposite side of high-grade gliomas and metastatic tumors(all P>0.05).There were significant differences in D *,D and f value of the tumor parenchyma,peritumoral edema(within 1 cm)and the normal centrum semiovale in the opposite side of every tumor group respectively(all P <0.05).Statistical analysis showed that statistical differences in D,D*,f,and r D*,r D,rf values were consistent between the two types of tumors.Conclusion IVIM-DWI can distinguish the differences of diffusion and perfusion information in parenchyma and regions of peritumoral edema between high-grade gliomas and brain metastases,which provides the basis for the differential diagnosis of the two tumor.