The investigators plan to accrue 30 patients for the present study. They are confident 30 patients will be sufficient to generate statistically significant results. In a study of the effects of brain tumor radiotherapy on normal brain as imaged by NMR spectroscopy, Urtasun et al were able to find statistically significant metabolite changes on proton MRS images with only 10 patients. In addition, the data to be utilized in the retrospective aspect of the study contains information on approximately 30 patients and their MRS scans. The trends found in this data will be used to guide data analysis for the prospective study. Finally, given the relative distribution and frequency of histologies seen in the new patient CNS clinic at the CCI, the investigators feel the target accrual of 30 patients is feasible within the time restraints of the project.