PT - JOURNAL ARTICLE AU - Kato, T. AU - Shinoda, J. AU - Oka, N. AU - Miwa, K. AU - Nakayama, N. AU - Yano, H. AU - Maruyama, T. AU - Muragaki, Y. AU - Iwama, T. TI - Analysis of <sup>11</sup>C-methionine Uptake in Low-Grade Gliomas and Correlation with Proliferative Activity AID - 10.3174/ajnr.A1242 DP - 2008 Nov 01 TA - American Journal of Neuroradiology PG - 1867--1871 VI - 29 IP - 10 4099 - http://www.ajnr.org/content/29/10/1867.short 4100 - http://www.ajnr.org/content/29/10/1867.full SO - Am. J. Neuroradiol.2008 Nov 01; 29 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 &lt; .005). In comparison of MET T/N ratios with the Mib-1 LI, a significant correlation was shown in DA (r = 0.63; P &lt; .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.