The Diagnostic Application Of ADC Value And Parameters Of Dynamic Contrast-enhanced Mri In The Pathological Grading Of Children’s Subtentorial Brain Tumors

Objective:To explore the diagnostic value of apparent diffusion coefficient（ADC）in the pathological grading of children’s subtentorial brain tumors.Methods:The apparent diffusion coefficient images of 70 cases were retrospectively analyzed,with subtentorial brain tumors confirmed by surgery and pathology in our hospital.According to the classification of tumors in the central vervous system of2016 World Health Organization（WHO）,13 cases were grade I,6 cases were grade II,6 cases were grade III and 45 cases were grade IV.The minimum ADC were measured in parenchyma of tumors with different pathological grades,the differences among the groups were statistically analyzed,receiver operating characteristic（ROC）curve were delineated,and the cutoff of ADC was predicted.Results:The mean minimum ADC values of subtentorial brain tumors in low-grade（I～II）were（1.08±0.33）×10^-3mm ²/s,and high-grade（III～IV）were（0.48±0.15）×10^-3mm ²/s,the difference between the two groups was statistically significant（P<0.001）,when the ADC value was less than 0.849×10^-3mm ²/s,the high-grade was possibility considered,with a sensitivity of 90.2%and a specificity of 94.7%.The mean minimum ADC values of grade I～IV were（1.17±0.31）×10^-3mm ²/s,（0.86±0.29）×10^-3mm ²/s,（0.65±0.16）×10^-3mm ²/s and（0.46±0.13）×10^-3mm ²/s,the difference between the grade III and IV is statistically significant（P<0.05）,when the ADC value was less than 0.578×10^-3mm ²/s,the grade IV was possibility considered,with a sensitivity of66.7%and a specificity of 91.1%.There is no statistically significant difference between grade I and II,so do grade II and III.Conclusions:The minimum ADC value is helpful for the grade diagnosis of children’s subtentorial brain tumors.Objective: To explore the application value of dynamic contrast-enhanced MRI perfusion parameters in the pathological grading of children’s subtentorial brain tumors,including volume transfer constant（Ktrans）,exchange rate constant（Kep）,volume of extra vascular extracellular space per unit volume of tissue（Ve）and i AUC.Methods: The Dynamic contrast-enhanced MRI（DCE-MRI）data of 70 cases with subtentorial brain tumors confirmed by surgery and pathology in our hospital were retrospectively analyzed.Among them,19 cases were low-grade（grade I to II）and 51 cases were high-grade（grade III to IV）.The perfusion parameters of DCE-MRI in parenchyma of tumors with different pathological grades were measured.MannWhitney U test and Spearman correlation analysis were performed,and ROC curve was drawn,to predict the cutoff of perfusion parameters.Results: The difference in Ktrans and Kep values between high and low grade of subtentorial brain tumors is statistically significant（P<0.001）.There is a positive correlation between Ktrans value and pathological grade,so does Kep.When the Ktrans value is more than 0.705min-1,the high-grade was possibility considered,with a sensitivity of 86.3% and a specificity of 84.2%（P<0.001）,when the Kep value is more than 0.612min-1,the high-grade was possibility considered,with a sensitivity of98% and a specificity of 63.2%（P<0.001）.The difference in Ve and i AUC values between high and low grade subtentorial brain tumors is no statistically significant（P>0.05）.Conclusions: The perfusion parameters of DCE-MRI（Ktrans,Kep）have important clinical significance in the pathological grading of children’s subtentorial brain tumors.