MRI in High-Grade Glioma Patients Undergoing Chemoradiation

Primary Objective: To determine the feasibility of interim PET-MRI in high-grade glioma patients undergoing chemoradiation by quantifying the proportion of high-grade glioma patients who are alive at 4 months post-radiation treatment and who have completed two PET scans and abbreviated cognitive testing pre-radiation treatment and at 4 months post radiation treatment. Secondary Objectives * To determine by machine learning if early changes on FDG-PET correlate with cognitive decline after radiation treatment. Cognitive impairment will be defined as a 1 standard deviation decline on any test. * To determine if baseline serum or cerebrospinal fluid markers or the change from baseline to 1-month are associated with patients with cognitive decline at 4-months after radiation treatment (defined as a 1 standard deviation decline on any test) compared to those without decline.