Objective: This study aims to evaluate the potential role of ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in detecting high-grade meningiomas and predicting the prognosis of patients after meningioma surgery.
Patients and methods: A total of 124 patients met the final inclusion criterion. Tumor to gray ratio (TGR) was compared with Ki-67 labeling index, and its correlations with pre-operative neurological function and treatment status were also evaluated. Receiver-operating characteristic (ROC) curve was drawn to determine a cut-off value which could discriminate meningioma of different grades. Prognostic factors including TGR were analyzed using Kaplan-Meier survival curve and cox proportional model.
Results: The TGR of higher World Health Organization (WHO) grade meningioma was significantly higher than that in lower grade (p < 0.001), and it was correlated with the Ki-67 labeling index (p < 0.001, r = 0.1545). The TGR of 1.30 was the best cutoff value for the detection of high grade (WHO grade II&III) meningioma from low grade (WHO grade I) according to ROC analysis, with a sensitivity of 61.5%, the specificity of 86.7%, and accuracy of 81.5%. The TGR (p < 0.001), treatment status (p = 0.035), tumor grade (p < 0.001) and Ki-67 labeling index (p < 0.001) were significantly associated with progression-free survival (PFS). Cox proportional hazards model demonstrated that TGR (p = 0.013) was an independent prognostic factor for PFS.
Conclusion: A high uptake of FDG was correlated with a more proliferative biological behavior and is a risk factor for tumor recurrence.
Keywords: meningioma, ¹⁸F-FDG PET, molecular imaging, clinical characteristic, prognosis