RT Journal Article SR Electronic T1 Analysis of 11C-methionine Uptake in Low-Grade Gliomas and Correlation with Proliferative Activity JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 1867 OP 1871 DO 10.3174/ajnr.A1242 VO 29 IS 10 A1 Kato, T. A1 Shinoda, J. A1 Oka, N. A1 Miwa, K. A1 Nakayama, N. A1 Yano, H. A1 Maruyama, T. A1 Muragaki, Y. A1 Iwama, T. YR 2008 UL http://www.ajnr.org/content/29/10/1867.abstract AB BACKGROUND AND PURPOSE: The relationship of 11C-methionine (MET) uptake and tumor activity in low-grade gliomas (those meeting the criteria for World Health Organization [WHO] grade II gliomas) remains uncertain. The aim of this study was to compare MET uptake in low-grade gliomas and to analyze whether MET positron-emission tomography (PET) can estimate tumor viability and provide evidence of malignant transformation.MATERIALS AND METHODS: We studied glioma metabolic activity in 49 consecutive patients with newly diagnosed grade II gliomas by using MET PET before surgical resection. On MET PET, we measured tumor/normal brain uptake ratio (T/N ratio) in 21 diffuse astrocytomas (DAs), 12 oligodendrogliomas (ODs), and 16 oligoastrocytomas (OAs). We compared MET T/N ratio among these 3 tumors and investigated possible correlation with proliferative activity, as measured by Mib-1 labeling index (LI).RESULTS: MET T/N ratios of DA, OD, and OA were 2.11 ± 0.87, 3.75 ± 1.43, and 2.76 ± 1.27, respectively. The MET T/N ratio of OD was significantly higher than that of DA (P < .005). In comparison of MET T/N ratios with the Mib-1 LI, a significant correlation was shown in DA (r = 0.63; P < .005) but not in OD and OA.CONCLUSION: MET uptake in DAs may be closely associated with tumor viability, which depends on increased amino acid transport by an activated carrier-mediated system. DAs with lower MET uptake were considered more quiescent lesions, whereas DA with higher MET uptake may act more aggressively.