Abstract： Objective:The ratio of related metabolites in magnetic resonance spectroscopy(1H-MRS)and the relative apparent diffusion coefficient(rADC),and relative fractional anisotropy(rFA)in diffusion tensor imaging(DTI)were evaluated.And the application value in high-grade gliomas(HGG)and brain metastatic tumors(BMT).Materials and Methods:The MR Data of 43 patients with gliomas and brain metastases confirmed by histopathology and clinical follow-up were collected from October 2016 to February 2023,including 25 cases of high-grade glioma and 18 cases of brain metastases.All patients were examined by routine brain MRI,MRS,DTI and T1WI enhanced scan.Obtaining the choline(Cho)/N-acetyl aspartate(NAA),Cho/creatine(Cr),NAA/Cr ratio of the tumor parenchyma,peritumoral edema(＜3 cm),and the ADC and FA values of the tumor parenchyma,peritumoral edema(＜3 cm),and contralateral white matter in the workstation.Calculating the relative ADC(rADC)values and relative FA(rFA)values to eliminate the influence of individual differences.Comparing the ages,genders and permeability parameters(Cho/NAA,Cho/Cr,NAA/Cr,rADC,rFA)of patients.In addition,the diagnostic values of each parameter were evaluated by the receiver operating characteristic(ROC)curve analysis,and the optimal cut-off values of each parameter as well as the corresponding sensitivity and specificity were calculated.The difference was statistically significant when P＜0.05.Results:There were no statistically significant differences in gender and age between HGG and BMT(P＞0.05).In the area of the tumor parenchyma,the values of Cho/NAA,NAA/Cr,and rFA between the two groups were significantly different(P＜0.05).There were no significant differences in Cho/Cr and rADC(P＞0.05).In the area of peritumoral edema,there were significant differences in quantitative parameters of Cho/NAA and Cho/Cr(P＜0.05).There were no significant differences in NAA/Cr,rFA,and rADC(P＞0.05).ROC curve showed that the quantitative quantitative parameters(Cho/NAA,NAA/Cr,and rFA)of the tumor parenchyma and the quantitative parameters(Cho/NAA,Cho/Cr)of the peritumoral edema were the most effective in the differential diagnosis of HGG and BMT.rFA was more efficient than other quantitative parameters.The diagnostic efficiency of combined quantitative parameters was the most significant with the maximum AUC of 0.934,and the corresponding sensitivity and specificity were 81.3%and 95.0%,respectively.Conclusions:The quantitative parameters(Cho/NAA,NAA/Cr,Cho/Cr,and rFA)measured by 1H-MRS and DTI were all helpful in distinguishing high-grade brain gliomas from brain metastases,and rFA was more efficient than other parameters.The combination of the quantitative parameters can further improve the diagnostic efficiency between high-grade glioma and brain metastatic tumor.