• Written informed consent will be obtained from each participants including healthy volunteers.

• Healthy volunteers will not have contra-indications to MR scanning, but will otherwise not be subject to other selection criteria.

• All patients will be enrolled in study # 2011-0370, the Stereotactic RadPath trial

• Patient is \>18 years old, agrees to participate in the clinical study and to complete all required visits and evaluations. The pediatric population has a different disease profile from the glioma patients we hope to recruit. To reduce heterogeneity in the patient population we will not consider patients younger than 18 for this study.

• Patient is a candidate for cerebral tumor resection with lesion suspected to be or previously biopsy proven to be a primary brain tumor.

• Patient is able to understand and give consent to participation in the study.

• Patient agrees to undergo, prior to the procedure, magnetic resonance imaging (MRI, within 14 days and preferably with 3 days of the planned procedure) with perfusion, diffusion and spectroscopic imaging.

• Patient has a GFR \> 60. In patients with moderate renal failure (GFR 30-60), an alternate injection with 2 times half-dose multihance (gadobenate dimeglumine) or gadovist (gadobutrol) will be considered, if a contrast exam is deemed clinically necessary.

• Specifically for this Study: Patient is willing to give signed informed consent for C13-Pyruvate MR Spectroscopy.