A key clinical application of MRSI has emerged in neuro-oncology and neuro-surgery by imaging the oncometabolite D-2-hydroxyglutarate (2HG)35 in mutant isocitrate dehydrogenase (IDH-1,2) gliomas36, that hence may be used for glioma sub-typing37. The gene discussed is IDH1; the disease is central nervous system cancer.