T1-dynamic Contrast Enhanced MR Imaging:Glioma Grading And Prediction Of Proliferation

Objective: To assess the permeability parameters,semiquantitative parameters and perfusion parameters of T1-dynamic contrast enhanced MR imaging in glioma grading,and the correlation of those parameters with Ki-67 expression.Methods: Totally 59 patients with gliomas were enrolled(18 with grade II,including 17 astrocytomas and 1 oligodendrogliomas;17 with grade III,including 11 astrocytomas and 7 oligodendrogliomas;24 with grade IV,including 23 glioblastomas and 1 gliosarcoma).Both conventional MRI and DCE dynamic perfusion scan were performed in all cases.The postprocessing procedure were implemented by omni kinetics software in workstation to obtain DCE permeability parameter maps(Ktrans,Kep,Ve and Vp),semiquantitative parameter maps(AUC,MAXConc,MAXSlope,TTP)and perfusion parameter maps(BV,BF and MTT).The manually delineated ROIs on every slice of MR were merged to cover entire parenchyma of tumor,and then the parameter values of the merged ROI,including mean,75 th and 90 th percentile values,were obtained.The parameters between high/lowgrade gliomas,II/III-grade and III/IV-grade were compared by Mann-Whitney U test,and the Receiver operating characteristic curve of the parameters was evaluated.Their correlation with Ki-67 LI were assessed by Spearman correlation analysis.Results: DCE permeability parameters(Ktrans,Ve and Vp),semi quantitative parameters(AUC,MAXConc)and perfusion parameters(BV,BF)can be well differentiated into different grades of gliomas.For high and low-grade gliomas,the corresponding Az value to Ktrans(0.911),Vp90th(0.913),AUC90th(0.905),BV90th(0.908)is preferred;for II/III grade gliomas,the corresponding Az value Ktrans(0.840),MAXslope(0.859),BV75th(0.843),Vp90th(0.846),AUC90th(0.853).For III/IV grade glioma,some parameters of DCE(Ktrans,Ve,AUC,MAXConc,BV)have the ability of differentiation,with corresponding value of Az to Ktrans(0.757),Ve(0.779),AUC75th(0.752),MAXCONc75th(0.777),BV75th(0.757).In the condition of excluding oligodendrocytes glioma,grading diagnosis ability of the above parameters of III/IV grade gliomas increased significantly,and corresponding parameters Az values as follows: Ve(0.860),AUC(0.826),Ktrans75th(0.856),MAXCONc75th(0.867),BV90th(0.845).Spearman analysis showed that the significant correlations were found between certain parameters and the Ki-67 LI: Ktrans(r=0.649),Vp(r=0.659),MAXConc(r=0.643),AUC(r=0.638),BF(r=0.696),BV(r=0.688);and under the circumstance of exclusion of oligodendrogliomas: Ktrans(r=0.725),Vp(r=0.729),MAXConc(r=0.722),AUC(r=0.725),BF(r=0.766),BV(r=0.763).Conclusion: T1-dynamic contrast enhanced MR can be used to differentiate high and lowgrade,II/III,III/IV grade gliomas and to predic the proliferation of gliomas with certain parameters;parameter values of 75 th and 90 th percentile is helpful to improve the diagnostic efficiency of differentiation.Therefore,DCE dynamic contrast MR imaging is an effective imaging technique for grading glioma and predicting its proliferation activity.