World Health Organization Grade II/III Glioma Molecular Status: Prediction by MRI Morphologic Features and Apparent Diffusion Coefficient

Background: A readily implemented MRI biomarker for glioma genotyping is currently lacking. Purpose: To evaluate clinically available MRI parameters for predicting isocitrate dehydrogenase (IDH) status in patients with glioma. Materials and Methods: In this retrospective study of patients studied from July 2008 to February 2019, untreated World Health Organization (WHO) grade II/III gliomas were analyzed by three neuroradiologists blinded to tissue results. Apparent diffusion coefficient (ADC) minimum (ADC(min)) and mean (ADC(mean)) regions of interest were defined in tumor and normal appearing white matter (ADC(NAWM)). A visual rating of anatomic features (T1 weighted, T1 weighted with contrast enhancement, T2 weighted, and fluid-attenuated inversion recovery) was performed. Inter observer comparison (intraclass correlation coefficient and Cohen kappa) was followed by nonparametric (Kruskal-Wallis analysis of variance) testing of associations between ADC metrics and glioma genotypes,including Bonferroni correction for multiple testing. Descriptors with sufficient concordance (intraclass correlation coefficient >0.8; kappa > 0.6) underwent univariable analysis. Predictive variables (P