Multimodal MR Imaging Study For Differentiation IDH Mutational Status In WHO Grade ?/? Astrocytoma

Objective: The purpose of this study was to examine whether DWI and DSC-PWI combined with c MRI could non-invasively predict IDH mutational status in WHO grade II/III astrocytomas in order to guide clinical diagnosis,treatment,and prognosis evaluation.Materials and methods: We retrospectively reviewed DWI,DSC-PWI and c MRI(T1WI,T2 WI,contrast enhanced T1WI)of 54 patients of Pathology confirmed WHO grade II/III astrocytomas.c MRI features(location,signal,edema,border,enhancement),minimum ADC(ADCmin),relative ADC(r ADC)and relative maximum CBV(r CBVmax)values were compared between IDH mutant and wild-type tumors.For analyzing data with Gaussian distribution,two independent samples t test was used.Otherwise,non-parametric Mann-Whitney U test was applied.Chi-square test was used to analyze the enumeration data.If the number of the four grid data was less than 5,the Fisher's method was used to analyze the data.Receiver operating characteristic curve(ROC)and Logistic regression was used to assess their diagnostic performances.Results: ADCmin and rADC were significantly higher in IDH mutated grade II/III astrocytomas than in IDH wild-type tumors(p<0.01).The maximum Youden index was chosen to determine the optimum thresholds of all the indicators in ROC analyses.Statistical analysis demonstrated ADCmin with the cut-off value of ? 1.01×10-3 mm2/s could differentiate the mutational status with sensitivity,specificity,PPV and NPV of72.22%,80.00%,93.50% and 41.90%.r ADC with the cut-off value of 1.60 could differentiate the mutational status with sensitivity,specificity,PPV and NPV of 72.22%,80.00%,93.50% and 41.90%.The threshold value <2.53 for r CBVmax in prediction of IDH mutation provided sensitivity,specificity,PPV and NPV of 94.44%,62.07%,90.90% and 73.60%.A combination of DWI,DSC-PWI and c MRI for identification of IDH mutations resulted in sensitivity,specificity,PPV and NPV of 92.3%,91.3%,96.1%and 83.60%.Conclusions: Compared with IDH wild-type tumors,IDH mutant tumors tend to have a higher ADCmin and r ADC,and a lower r CBVmax.Application of c MRI with advanced imaging modalities such as DWI and DSC-PWI is useful to predict IDH mutational status in grade II/III astrocytomas.Multimodal MRI technique may noninvasive predicting IDH mutational status.