The introduction of hybrid PET/MRI systems allows simultaneous multimodality image acquisition of high technical quality. This technique is well suited for the brain, and particularly in dementia and neuro-oncology. In routine use combinations of well-established MRI sequences and PET tracers provide the most optimal and clinically valuable protocols. For dementia the [18F]-fluorodeoxyglucose (FDG) has merit with a simultaneous four sequence MRI protocol of 20 min supported by supplementary statistical reading tools and quantitative measurements of the hippocampal volume. Clinical PET/MRI using [18F]-fluoro-ethyl-tyrosine (FET) also abide to the expectations of the adaptive and versatile diagnostic tool necessary in neuro-oncology covering both simple 20 min protocols for routine treatment surveillance and complicated 90 min brain and spinal cord protocols in pediatric neuro-oncology under general anesthesia. The clinical value of adding advanced MRI sequences in multiparametric imaging setting, however, is still undocumented.