胶质瘤的18F-FDC PET影像分析

Objective Analyzing the characteristics of 18F-FDG PET imaging to improve accuracy in preoperative diagnosis and differentiation of postoperative recurrence from radiation necrosis in gliomas. Methods 84 were composed of 56 cases with astrocytic tumor, 15 with oligodendroglial tumor, 8 with mixed glioma and S with ependymal tumor. All of them had definite postoperative pathology results. 18F-FDG PET scan was performed before operation. After getting images, distribution of 5F-FDG was visually viewed. Meanwhile, ratios of T/WM(Tumor/white matter) and T/C(Tumor/Cortex) were measured, respectively. Results Compared with normal contralateral corresponding region, there was a decrease of uptake 18F-FDG in 6 cases with astrocytoma WHO grade 1. There was an increased accumulation of 18F-FOG in other 50 cases with astrocytomas. Lesions in 8 mixed gliomas WHO grade Ⅱ and 5 ependymomas WHO grade Ⅱ also presented with high uptake of 18F-PDG. Uptake of 18F-FDG in 4 patients with anaplastic oligodendroglioma WHO grade Ⅲ was high, while 11 with oligodendroglioma WHO grade Ⅱ presented with hypometabolism in 18F-FOG PET. According to different uptake of 18F-FDG, it was reasonable to classify all lesions into two groups. Lesions with oligodendroglioma WHO grade II and astrocytoma WHO grade I belonged to low uptake of 18F-FDG group, other lesions belonged to high uptake of 18F-FDG group. Meanwhile, there was a significant difference in uptake of 18F-FDG; between different grade astrocytomas and oligodendrogliomas (P＜0.01). The more malignant gliomas were, the more uptake of was. Conclusion Uptake degree of 18F-FDG varied with pathology and malignancy in gliomas. 18F-FDG PET could be used to grade gliomas. All lesions could be classified into hypometabolism and hypermetaholism according accumulation of 18F-FDG. 18F-FDG PET could he used to make a diagnosis and differentiate recurrence from radiation necrosis in gliomas with hypermetabolism, but could not he used to do them in gliomas with hypometabolism.