High field MR-technologies are expected to boost metabolic spectroscopic imaging (MRSI), but also CEST-MRI. This is due to the fact that increased SNR is available which can be used to increase the spatial resolution of all sequences, or reduction of measurement times. Recent findings has shown that MRSI can be used to evaluate the isocitrate dehydrogenase (IDH) status of gliomas, a brain tumor type which is most often diagnosed in humans. Patients with IDH-mutated gliomas have a much longer survival time that IDH-wildtype. In IDH-mutated gliomas the substance 2-hydroxy-glutarate (2HG) is found, whereas in IDH-wildtype gliomas it is not. The underlying trial aims to measure 2HG directly with different MRSI sequences at 3 Tesla (3T) and 7 Tesla (7T) magnetic field strength. Apart from MRSI-techniques for IDH-typing it has been shown that CEST-imaging can also be performed to determine the IDH-status of gliomas. A total of 75 patients and 50 healthy controls will be examined in this study to evaluate the most accurate method for pre-operative IDH-status determination.