The results reveal that an optimized semi-LASER MRS sequence offers high sensitivity and localization for in vivo detection of 2-HG, characteristic of IDH-mutated brain tumors, at 3 T. The use of a long TE (110 milliseconds) not only enables direct detection of the H3/H3′ multiplet of 2-HG at 1.9 ppm in the in vivo spectra but also generates reduced fitting correlations with overlapping Glu and Gln resonances and improved fitting of Lac compared with an existing long-TE PRESS sequence (16). This evidence concerns the gene IDH2 and brain neoplasm.