Metabolic alteration of D-2-hydroxyglutarate (D-2HG) production is a hallmark for IDH mutation in gliomas.67 Recently, a number of groups have demonstrated reliable detection of D-2HG using in vivo 1H MRS.68–70 Andronesi et al.68 reported apparent in vivo detection of D-2HG using 2D correlation spectroscopy (COSY) and J-difference spectroscopy in IDH1-mutated gliomas. The gene discussed is IDH1; the disease is glioma.