Alternatively, the use of proton MR spectroscopy for the non-invasive evaluation of signal changes of the oncometabolite 2-hydroxyglutarate related to IDH mutations is an option for response assessment, but this technique is highly prone to susceptibility artefacts due to bone, hemorrhage, calcifications, or surgical material and may even be false-positive in 20% of patients with newly diagnosed IDH-wildtype glioblastoma [79, 80]. This evidence concerns the gene IDH1 and glioblastoma.