MRI Hypoxia Study for Glioblastoma Multiforme (GBM) Radiation Therapy

Inclusion Criteria: * Suspected high-grade glioma (HGG) / glioblastoma multiforme (WHO grade IV) at initial radiological examination * Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2 * Available for scanning on two separate days Exclusion Criteria: * Women lactating, pregnant or of childbearing potential who are not willing to avoid pregnancy during the study * Patients with a history of severe renal disease(s) (eGFR \<20) that cannot tolerate gadolinium chelate contrast agents. * Geographically remote patients unable to agree to imaging schedule * Patients who have received anti - vascular endothelial growth factor (anti-VEGF) monoclonal antibody therapy the 3 months prior to recruitment * Patients with a history of psychological illness or condition such as to interfere with the patient's ability to understand the requirements of the study. * Patients with significant cardiac or pulmonary disease including cardiac arrythmias or Chronic Obstructive Pulmonary Disease (COPD) that are unable to tolerate high flow O2 for oxygen contrast. * Patients taking carbonic anhydrase inhibitors (Acetazolamide) * History of glaucoma * Any implant, foreign body, 3 Tesla (3T) MRI incompatible device, or other contraindication to MRI imaging.