Experimental study on multiple tracers PET/CT in the differentiation of C6 glioma from different inflammation

Abstract

Objective To investigate the value of 18F-FDG, 11C-MET and 11C-CHO PET/CT in the differentiation of C6 glioma from different kinds of inflammation in experimental rat models. Methods (1) A total of 48 male SD rats were randomly divided into 6 groups by the random number table: group 1 and 2 consisted of 8 rats bearing both C6 glioma and turpentine oil-induced acute inflammation; group 3 and 4 consisted of 8 rats bearing both C6 glioma and turpentine oil-induced chronic inflammation; group 5 and 6 consisted of 8 rats bearing both C6 glioma and BCG-induced granuloma. (2) 18F-FDG and 11C-MET PET/CT were performed on rats of group 1, 3 and 5; 18F-FDG and 11C-CHO PET/CT were performed on rats of group 2, 4 and 6. The lesion-to-muscle ratios and tumor selectivity index (SI) were calculated. (3)After the PET/CT imaging, the lesions were excised. Immunohistochemical staining was used to demonstrate the situation of Glut-1, HIF-1α and CD98. (4)Two-sample t test, Nemenyi test and nonparametric Kruskal-Wallis H test were used for statistical analyses. Results (1) 18F-FDG and 11C-MET uptake in C6 glioma were higher than those in different inflammatory tissues(t=1.425-3.901, all P 0.05). In group 1 and 5 models, SIMET (4.22±2.96 and 4.89±2.08) was significantly higher than SIFDG (1.77±0.86 and 1.72±0.77; t=2.717 and 2.490, both P 0.05). (2) Immunohistochemical study showed that there were significant differences in the expression of HIF-1α, CD98 among different lesions (H=17.810, 26.540, both P 0.05). Nemenyi test showed that there was significant difference for CD98 expression between C6 glioma and acute inflammation, C6 glioma and granuloma (χ2=5.504, 9.345, both P<0.05), and for HIF-1α and CD98 expression between C6 glioma and chronic inflammation (χ2=-5.938, 2.128, both P<0.05). Conclusions Compared with 18F-FDG and 11C-CHO, 11C-MET has better tumor specificity. 11C-CHO PET/CT is not suitable for the differentiation of tumor and inflammation because of its lowest specificity. Key words: Glioma; Inflammation; Tomography, emisssion-computed; Deoxyglucose; Methionine; Choline; Rats