The objective of the current study is to investigate the changes that occur in tumor related magnetic resonance (MR) spectra over the course of radical radiotherapy for malignant glioma. The primary endpoint for the study will be to identify characteristic evolving metabolite patterns on MRSI, before, during, and after radiotherapy that correlate with overall survival, and progression-free survival in high grade gliomas. Secondary endpoints will involve correlation of MRSI metabolite patterns with time to progression and Karnofsky performance status.