PT  - JOURNAL ARTICLE
AU  - K. Takano
AU  - M. Kinoshita
AU  - H. Arita
AU  - Y. Okita
AU  - Y. Chiba
AU  - N. Kagawa
AU  - Y. Fujimoto
AU  - H. Kishima
AU  - Y. Kanemura
AU  - M. Nonaka
AU  - S. Nakajima
AU  - E. Shimosegawa
AU  - J. Hatazawa
AU  - N. Hashimoto
AU  - T. Yoshimine
TI  - Diagnostic and Prognostic Value of <sup>11</sup>C-Methionine PET for Nonenhancing Gliomas
AID  - 10.3174/ajnr.A4460
DP  - 2015 Sep 17
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2015/09/17/ajnr.A4460.short
4100  - http://www.ajnr.org/content/early/2015/09/17/ajnr.A4460.full
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 tumor-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.AbbreviationsMET11C-methioninePFSprogression-free survivalT/Ntumor-to-normal tissueT/Naveaverage tumor-to-normal tissueT/Nmaxmaximum tumor-to-normal tissue