To clarify in vivo hypoxia and glucose metabolism in relation to IDH mutation and 1p/19q codeletion status, we retrospectively analyzed the hypoxia as assessed by positron emission tomography (PET) with [18F]-fluoromisonidazole (FMISO) and glucose metabolism as assessed by PET with [18F]-fluoro-2-deoxy-d-glucose (FDG) in newly diagnosed malignant (WHO grade III and IV) gliomas. The gene discussed is IDH1; the disease is central nervous system cancer.