RT Journal Article SR Electronic T1 Diagnostic and Prognostic Value of 11C-Methionine PET for Nonenhancing Gliomas JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 44 OP 50 DO 10.3174/ajnr.A4460 VO 37 IS 1 A1 Takano, K. A1 Kinoshita, M. A1 Arita, H. A1 Okita, Y. A1 Chiba, Y. A1 Kagawa, N. A1 Fujimoto, Y. A1 Kishima, H. A1 Kanemura, Y. A1 Nonaka, M. A1 Nakajima, S. A1 Shimosegawa, E. A1 Hatazawa, J. A1 Hashimoto, N. A1 Yoshimine, T. YR 2016 UL http://www.ajnr.org/content/37/1/44.abstract AB BACKGROUND AND PURPOSE: Noninvasive radiologic evaluation of glioma can facilitate correct diagnosis and detection of malignant transformation. Although positron-emission tomography is considered valuable in the care of patients with gliomas, 18F-fluorodeoxyglucose and 11C-methionine have reportedly shown ambiguous results in terms of grading and prognostication. The present study compared the diagnostic and prognostic capabilities of diffusion tensor imaging, FDG, and 11C-methionine PET in nonenhancing gliomas.MATERIALS AND METHODS: Thirty-five consecutive newly diagnosed, histologically confirmed nonenhancing gliomas that underwent both FDG and 11C-methionine PET were retrospectively investigated (23 grade II and 12 grade III gliomas). Apparent diffusion coefficient, fractional anisotropy, and tumor-to-normal tissue ratios of both FDG and 11C-methionine PET were compared between grade II and III gliomas. Prognostic values of these parameters were also tested by using progression-free survival.RESULTS: Grade III gliomas showed significantly higher average tumor-to-normal tissue and maximum tumor2-to-normal tissue than grade II gliomas in 11C-methionine (P = .013, P = .0017, respectively), but not in FDG-PET imaging. There was no significant difference in average ADC, minimum ADC, average fractional anisotropy, and maximum fractional anisotropy. 11C-methionine PET maximum tumor-to-normal tissue ratio of 2.0 was most suitable for detecting grade III gliomas among nonenhancing gliomas (sensitivity, 83.3%; specificity, 73.9%). Among patients not receiving any adjuvant therapy, median progression-free survival was 64.2 ± 7.2 months in patients with maximum tumor-to-normal tissue ratio of <2.0 for 11C-methionine PET and 18.6 ± 6.9 months in patients with maximum tumor-to-normal tissue ratio of >2.0 (P = .0044).CONCLUSIONS: 11C-methionine PET holds promise for World Health Organization grading and could offer a prognostic imaging biomarker for nonenhancing gliomas.MET11C-methioninePFSprogression-free survivalT/Ntumor-to-normal tissueT/Naveaverage tumor-to-normal tissueT/Nmaxmaximum tumor-to-normal tissue