Feasibility of Evaluating the Histologic and Genetic Subtypes of WHO Grade II-IV Gliomas by Diffusion-Weighted Imaging
Abstract Background: To explore the feasibility of diffusion-weighted imaging (DWI) metrics in order to predict the histologic subtypes and genetic status (e.g., IDH, MGMT, and TERT) of glioma noninvasively.Methods: One hundred and eleven patients with pathologically confirmed WHO grade II-IV gliomas were recruited retrospectively. Apparent diffusion coefficient (ADC) values were measured in solid parts of gliomas on co-registered T2-weighted images and were compared with each other in terms of WHO grading and genotypes using t tests. Receiver operating characteristic analysis was performed to assess the diagnostic performances of ADC. Subsequently, multiple linear regression was used to find independent variables, which can affect ADC values.Results: The values of overall mean ADC (omADC) and normalized ADC (nADC) of glioblastoma and IDH wildtype gliomas were lower than lower grade gliomas and IDH mutated gliomas (P<0.05). nADC values showed better diagnostic performance than omADC in identifying tumor grade (AUC: 0.749 vs. 0.716) and IDH status (AUC: 0.836 vs. 0.777). ADC values had limited abilities in distinguishing TERT status (AUC=0.607 for nADC and 0.617 for omADC) and MGMT status (AUC=0.651 for nADC). Only tumor grade and IDH status were tightly associated with ADC values.Conclusion: DWI metrics can predict glioma grading and IDH mutation noninvasively, but has limited use in the detection of TERT mutation and MGMT methylation.