Fig. 3.

Representative PET and MRI images of radiation necrosis (RN), anaplastic astrocytoma (AA), anaplastic oligodendroglioma (AO), and glioblastoma (GBM) are shown. RN: A 45-year-old man. ¹¹C-methionine (MET)-PET/Gd volume ratio = 57.0%, MET-PET/Gd overlap ratio = 57.0%, ¹¹C-choline (CHO)-PET/Gd volume ratio = 81.5%, CHO-PET/Gd overlap ratio = 81.5%, ¹⁸F-fluorodeoxyglucose (FDG)-PET/Gd volume ratio = 0%, FDG-PET/Gd overlap ratio = 0%, MET lesion/normal brain uptake ratio (L/N ratio) = 3.34, CHO L/N ratio = 2.03, and FDG L/N ratio = 1.57. AA: A 67-year-old man. MET-PET/Gd volume ratio = 189.4%, MET-PET/Gd overlap ratio = 100%, CHO-PET/Gd volume ratio = 121.3%, CHO-PET/Gd overlap ratio = 100%, FDG-PET/Gd volume ratio = 0%, FDG-PET/Gd overlap ratio = 0%, MET L/N ratio = 3.39, CHO L/N ratio = 7.7, and FDG L/N ratio = 1.65. AO: A 51-year-old man. MET-PET/Gd volume ratio = 172.7%, MET-PET/Gd overlap ratio = 100%, CHO-PET/Gd volume ratio = 107.8%, CHO-PET/Gd overlap ratio = 95.3%, FDG-PET/Gd volume ratio = 0%, FDG-PET/Gd overlap ratio = 0%, MET L/N ratio = 5.03, CHO L/N ratio = 14.41, and FDG L/N ratio = 1.31. GBM: A 35-year-old man. MET-PET/Gd volume ratio = 164.9%, MET-PET/Gd overlap ratio = 100%, CHO-PET/Gd volume ratio = 109.2%, CHO-PET/Gd overlap ratio = 98.7%, FDG-PET/Gd volume ratio = 74.3%, FDG-PET/Gd overlap ratio = 67.5%, MET L/N ratio = 5.21, CHO L/N ratio = 17.94, and FDG L/N ratio = 2.33. MRI: magnetic resonance imaging, PET: positron emission tomography.