Differential diagnosis of rat C6 glioma and inflammation with 18F-FDG, 11C-MET and 11C-CHO PET/CT imaging and their correlations with HIF-1α and VEGF

Abstract

Objective To compare 18F-FDG、11C-MET and 11C-CHO PET/CT in rat C6 glioma and inflammation models and observe their correlations with HIF-1α and VEGF expressions. Methods Thirty-two male Wistar rats were included to bear both C6 glioma and turpentine oil-induced acute inflammation (AI). 18F-FDG, 11C-MET and 11C-CHO PET/CT were performed on rats. The SUVmax ratios of tumor-to-muscle (T/M), AI-to-muscle (AI/M) and tumor selectivity index (SI) were calculated. One-way analysis of variance and two-sample t test were used for statistical analyses. HIF-1α and VEGF expression was detected by immunohistochemical staining. Spearman correlation analysis was performed to evaluate the relationship between T/M ratios and the expressions of HIF-1α or VEGF. Results T/M ratios of 18F-FDG, 11C-MET and 11C-CHO in C6 glioma were 6.89±2.53, 2.75±0.87, 2.73±1.01, and the AI/M were 4.77±2.21, 1.75±0.66, 2.23±0.90 respectively. The 18F-FDG and 11C-MET uptake between C6 glioma and AI were significantly different(tFDG=2.133, tMET=3.267, both P 0.05). T/M ratios of 18F-FDG and 11C-MET were positively related to HIF-1α and VEGF expressions(rs=0.725, 0.637, 0.621, 0.764, all P<0.05). The T/M ratio of 11C-CHO related only to VEGF (rs=0.682, P<0.05). Conclusions 18F-FDG and 11C-MET PET/CT may differentiate C6 glioma from AI, and 11C-MET PET/CT seems more tumor-selective. 11C-CHO PET is less valuable for the differential diagnosis. The 18F-FDG and 11C-MET uptake of C6 glioma may be related to tumor hypoxia. All the three tracers could reflect tumor angiogenesis, but with different sensitiveness. Key words: Glioma; Inflammation; Deoxyglucose; Methionine; Choline; Tomography, emission-computed; Tomography, X-ray computed; Rats