Application Study Of 3.0T Multimodal Magnetic Resonance Imaging In The Grading Of IDH Mutant And 1p/19q Co-deleted Oligodendroglial Tumors

Objective: The aim of this study was to investigate whether 3.0T multimodal functional magnetic resonance imaging techniques including diffusion-weighted imaging(DWI),susceptibility weighted imaging(SWI)and dynamic susceptibility contrast perfusion-weighted imaging(DSC-PWI)are able to stratify WHO grades of IDH mutant and 1p/19 q co-deleted oligodendrogliomas preoperatively according to the 2016 World Health Organization(WHO)classification of tumors of the central nervous system.This study was also designed to investigate the optimal diagnostic parameter and protocol for grading this novel entity as a clinical guide to noninvasive integrated diagnosis,individualized treatment,and prognosis evaluation.Materials and Methods: Thirty-three patients were retrospectively reviewed with their conventional MRI(unenhanced and enhanced),DWI,SWI and DSC-PWI obtained on pathologically confirmed oligodendrogliomas with IDH mutation and 1p/19 q co-deletion.All patients were enrolled into two groups based on the WHO grades: IDH mutant and 1p/19 q co-deleted oligodendrogliomas(WHO grade II,low-grade),IDH mutant and 1p/19 q co-deleted anaplastic oligodendrogliomas(WHO grade III,high-grade).Features of c MRI(location,signal,border,edema and enhancement),minimum ADC(ADCmin),normalized ADC(n ADC),intratumoral susceptibility signals(ITSSs),normalized maximum CBV(n CBV),normalized maximum CBF(n CBF),normalized MTT(n MTT),normalized peak high(n PH),and percentage of signal recovery(PSR)were compared between grades.Non-parametric Mann-Whitney U tests were applied for analyzing measurement data between groups.Either Pearson's Chi-square test or Fisher's exact test was applied to analyze the enumeration data and ranked data across groups.Receiver operating characteristic(ROC)curve and logistic regression analysis were applied to determine the diagnostic performances of multiple parameters derived from multimodal MRI,and to investigate the optimal grading protocol.Results: Genetically defined(IDH mutant and 1p/19 q co-deleted)anaplastic oligodendrogliomas(high-grade tumors)had a tendency to present with more prominent enhancement and edema when compared to their counterpart(low-grade tumors).ADCmin,n ADC,ITSSs,n CBV and n CBF were significantly different between groups(all P values < 0.05).Optimal cut-off values of n ADC(a quantitative parameter derived from DWI)and n CBV(a quantitative parameter derived from DSC-PWI)in the differentiation of high-grade from low-grade tumors were determined as ?1.11 and?2.90,respectively.The sensitivity/specificity of n ADC and n CBV were100.00%/77.78% and 92.31%/80.00%,respectively.With a threshold value of ? 1 for ITSS(a semi-quantitative parameter derived from SWI),the sensitivity and specificity in the diagnosis of anaplastic tumors were 60.00% and 83.33%,respectively.The combination of SWI and DSC-PWI for grading resulted in the best sensitivity,specificity,and area under the curve of 100.00%,93.33%,and 0.99,respectively.Conclusion: IDH mutant and 1p/19 q co-deleted ODs can be stratified by grades using conventional MRI and multimodal MRI techniques(including DWI,SWI,and DSC-PWI).n ADC,ITSS,and n CBV could be used to provide physiological information(including cellularity,angiogenesis,and micro-hemorrhage)of neoplastic histology and predict tumor grade in such tumors.Combined ITSSs with n CBV appear to be the most promising option for grading genetically defined ODs based on the modern WHO standard in clinical practice.