Magnetic resonance spectroscopy (MRS) can detect IDH mutations in gliomas with high specificity by identifying the presence of 2-hydroxyglutarate (2HG).39, 40, 41This may be particularly useful in areas with limited access to next-generation testing for full IDH profiling or for tumors in difficult-to-access locations such as the brainstem. This evidence concerns the gene IDH2 and central nervous system cancer.