Advanced diffusion-weighted MRI (ADW-MRI) offer the opportunity of higher sensitivity towards subtle tissue changes associated with increased specificity relating to damage of different tissue components of the central nervous system (CNS). Within the framework of this study, conventional follow up MRI will be complemented by ADW-MRI in case of suspected tumor recurrence and possible surgical resection of the suspicious tissue. In the case of surgical resection, the histopathological findings will be correlated to the findings of the ADW-MRI. In the depicted pilot phase, the feasibility of the described protocol will be examined and the data concerning correlations between standard histopathologic and genetic workup of the resected tissue and the results concerning tissue features from ADW-MRI will be analyzed.