This clinical trial studies whether advanced magnetic resonance imaging (MRI) techniques, including diffusion-relaxation correlation spectrum imaging (DR-CSI) and sodium imaging, can be used to identify the difference between brain tumors that come back after a period of improvement (recurrent) and treatment-related tissue damage (radiation necrosis \[RN\]). Radiation therapy is often used in the treatment of brain tumors. Radiation treatment response can be difficult to assess and is usually done using conventional MRI, which uses radio waves and a powerful magnet linked to a computer to create detailed pictures of areas inside the body. Current imaging techniques have a limited ability to identify the difference between recurrent brain tumor and RN due to their similar appearance on conventional MRI and overlapping clinical presentation. This makes it hard for doctors to plan the best way to treat these tumors. DR-CSI is a new MRI technique with the potential to detect microscopic tissue components with different characteristics. Sodium imaging is an MRI technique that estimates the total sodium concentration in the obtained images. It may be able to identify the small structures within the tissue of brain tumors. Advanced MRI techniques like DR-CSI and sodium imaging may be effective in identifying the difference between recurrent brain tumors and RN.