 MRS and 11C-MET PETCT are commonly used as supplementary imaging techniques for the differential diagnosis of non-enhancing supratentorial gliomas. However, both techniques have limitations leading to misdiagnosis; therefore, the investigators attempted to combine these two metabolic imaging tools to evaluate whether the combination of MRS and 11C-MET PETCT can increase the sensitivity of the radiological diagnosis of non-enhancing supratentorial gliomas. 