MGMT and central nervous system cancer: Limitations of our study include the still relatively low number of patients, especially with dynamic FET-PET and low-grade gliomas, which reduces the validity particularly for the discrimination of low-grade gliomas by dynamic imaging; the retrospective study design, and, consequently, the lack of a consistent molecular pathologic evaluation e.g., with respect to IDH, MGMT, and 1p19q status, all of which could be addressed in future prospective studies, preferably performed in a hybrid PET/MRI setting.