Fig 2. Left top, Contrast-enhanced, T1-weighted image. Right top, MET PET is superimposed on MR imaging. Left bottom, CHO PET is superimposed on MR imaging. Right bottom, FDG PET is superimposed on MR imaging. A, A 32-year-old woman presented with diffuse astrocytoma. MET T/N ratio = 1.72, CHO T/N ratio = 1.38, and FDG T/N ratio = 0.66. B, A 23-year-old woman presented with oligoastrocytoma. MET T/N ratio = 2.76, CHO T/N ratio = 1.82, and FDG T/N ratio = 0.92. C, A 44-year-old man presented with oligodendroglioma. MET T/N ratio = 3.71, CHO T/N ratio = 2.74, and FDG T/N ratio = 1.07. D, A 62-year-old woman presented with anaplastic astrocytoma. MET T/N ratio = 4.26, CHO T/N ratio = 10.17, and FDG T/N ratio = 1.24. E, A 68-year-old man presented with glioblastoma multiforme. MET T/N ratio = 6.85, CHO T/N ratio = 33.38, and FDG T/N ratio = 2.55.