胶质瘤的^(18)F-FDG PET影像分析

Analysis of ^(18)F-FDG PET imaging of patients with gliomas

目的分析不同病理类型胶质瘤18FFDGPET影像特征,提高其对胶质瘤术前诊断和术后复发与放射坏死鉴别诊断准确率。方法经病理证实的胶质瘤84例,包括星形细胞瘤为56例,少突胶质细胞瘤15例,WHOⅡ混合性胶质瘤8例,WHOⅡ室管膜瘤5例。采用SiemensECAT47PET扫描仪行术前18FFDGPET脑显像。目视法观察胶质瘤肿瘤灶18FFDG分布,采用ROI,与对侧对应正常部位比较,判断病灶的代谢程度。结果56例星形细胞瘤中,WHOⅠ级6例18FFDG分布低于对侧相应部位的分布。Ⅱ级21例、Ⅲ级13例和Ⅵ级16例呈不同程度的18FFDG摄取增高。15例少突胶质细胞瘤中,WHOⅡ级11例呈18FFDG摄取减低。Ⅲ级4例呈18FFDG摄取明显增高。WHOⅡ级混合性胶质瘤8例和室管膜瘤5例,都呈18FFDG摄取增高。根据胶质瘤对18FFDG摄取程度,可将病灶分为代谢减低灶和增高灶两类。Ⅰ级星形细胞瘤和Ⅱ级少突胶质瘤为18FFDG摄取减低灶。星形细胞瘤Ⅱ、Ⅲ、Ⅳ级,Ⅱ级混合性胶质瘤,Ⅱ级室管膜瘤,Ⅲ级少突胶质细胞瘤为18FFDG摄取增高灶。不同级别星形细胞瘤和不同级别的少突胶质瘤的T/C,T/WM有明显差异,两两比较,P值都<0.01。结论胶质瘤对18FFDG摄取程度与肿瘤病理类型和肿瘤恶性程度有关,18FFDGPET可用于胶质瘤分级。根据对18FFDG的摄取程度,胶质瘤可分为高代谢灶和低代谢灶两类,18FFDGPET可用于高代谢胶质瘤的诊断与术后复发与放射坏死的鉴别,不能用于低代谢灶的诊断与鉴别诊断。

Objective Analyzing the characteristics of is F-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 5 with ependymal tumor. All of them had definite postoperative pathology results, ^18F-FDG PET scan was performed before operation. After getting images, distribution of is F-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 of ^18F-FDG in 6 cases with astrocytoma WHO grade Ⅰ. There was an increased accumulation of is F-FDG 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-FDG. Uptake of ^18F-FDG in 4 patients with anaplastic oligodendroglioma WHO grade m was high, while 11 with oligodendroglioma WHO grade Ⅱ presented with hypometabolism in ^18F-FDG 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 ^18F-FDG 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 hypermetabolism according accumulation of ^18F-FDG, ^18F-FDG PET could be used to make a diagnosis and differentiate recurrence from radiation necrosis in gliomas with hypermetabolism, but could not be used to do them in gliomas with hypometabolism.