| Abstrakt: |
Positron emission tomography combined with computed tomography (PET/CT) is currently the standard imaging method in neuro-oncology for gliomas and metastatic lesions. There is much less experience with the use of PET/CT in meningioma, the most common primary tumor of the central nervous system, and there are some differences in how results are interpreted. The aim of the present work was to assess the potential for and features of the use of PET/CT to determine the degree of malignancy of meningioma, its prevalence, responses to radiotherapy, and diagnosis of relapse and/or post-radiation changes based on our own clinical experience and review of the literature. The study included 70 patients with 77 meningiomas who underwent 11C-methionine PET/CT. Mean age at investigation was 57.4 years (range 19–86 years). The main parameter evaluated, the tumor/normal ratio (T/N) of 11C-methionine (11C-MET) in tumors, averaged 3.13 (1.00–10.66). Meningiomas had high 11C-MET T/N, with values of >1.5 in 89.6% of cases. In histologically verified malignancy grade 1, 2, and 3 meningiomas (WHO scale), median T/N values were 4.06 [3.04; 4.57], 2.32 [2.12; 3.69], and 4.29 [2.60; 5.10] respectively, with no significant between-group differences. At the same time, non-growing or slowly growing histologically unverified meningiomas, i.e., incidentally discovered, had significantly lower 11C-MET T/N than grade 1 and 3 meningiomas. There was no significant difference in T/N between irradiated meningiomas with controls for tumor growth (3.81 [2.97, 3.98]) and relapse (3.62 [2.60, 4.30]). Comparison of irradiated and non-irradiated grade 1, 2, and 3 meningiomas, as well as the combined group of grade 1–3 tumors, revealed no significant differences in 11C-MET T/N. The use of PET/CT for meningiomas has a number of important characteristics. Meningiomas had high 11C-MET T/N. Our data indicate that 11C-MET PET/CT does not distinguish between meningiomas with different degrees of malignancy, i.e., WHO grades 1, 2, and 3. 11C-MET T/N in meningiomas remains stably high or shows a slight decrease in cases with effective radiotherapy and long-term local control. Comparison of growing and non-growing meningiomas revealed no significant differences in 11C-MET T/N between irradiated and non-irradiated tumors. [ABSTRACT FROM AUTHOR] |
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