The purpose of the research study is to test new methods that could improve diagnosis and assessment of brain tumors. One of these methods is a new MR (magnetic resonance) imaging technique called magnetic resonance fingerprinting (MRF), which allows for rapidly scanning the patient and provides quantitative information on tumor tissue. The investigators will compare the data gathered from MR Fingerprinting with other imaging tests, clinical information, treatment details and biopsy results to evaluate the accuracy of this new technique.