RecruitingProcedureMRE Scan for the Assessment of Differences in Tissue Stiffness Between Radiation Necrosis and Recurrent Glioma in Patients With Previously Treated GliomasThis trial uses magnetic resonance elastography (MRE) to estimate tissue stiffness (hardness or softness of the tissue) in tissue that is affected by radiation treatment (radiation necrosis) and tumor tissue that has come back (recurrent) after treatment in patients with gliomas. Diagnostic procedures, such as MRE, may estimate the differences in tissue stiffness between radiation necrosis and recurrent glioma post treatment and ultimately lead to a more accurate diagnosis and/or surgery, and/or a better assessment of the disease's response to treatment.