Development of MRF for Characterization of Brain Tumors After Radiotherapy

The purpose of this study is to discover the potential convenience and ease of using a Magnetic Resonance Imaging (MRI) technique, named Magnetic Resonance Fingerprinting (or MRF), to achieve high-quality images within a short scan time of 5 min for viewing the entire brain. This is an advanced quantitative assessment of brain tissues. This method is being applied with IVIM MRI to be able to tell the difference between a brain with radiation necrosis and a brain with tumor recurrence. Participants will consist of individuals who have received radiation therapy in the past and were diagnosed with radiation necrosis, individuals with recurrent tumors, individuals with previously untreated tumors, and healthy individuals who have no brain diseases and have not had radiation treatment to the brain. Participants will undergo an MRI scan at a one-time research study visit; no extra tests or procedures will be required for this research study. The primary objectives of this study are: * To demonstrate the clinical feasibility of combining MRF with state-of-the-art parallel imaging techniques to achieve high-resolution quantitative imaging within a reasonable scan time of 5 min for whole brain coverage. * To apply the developed quantitative approach in combination with IVIM MRI for differentiation of tumor recurrence and radiation necrosis. * To investigate the effect of radiation dose on the development of radiation necrosis and tumor recurrence.