In glioma patients, differentiation between tumor progression (TP) and treatment-related changes (TRCs) remains challenging. Difficulties in classifying imaging alterations may result in a delay or an unnecessary discontinuation of treatment. PET using O-(2-¹⁸F-fluoroethyl)-l-tyrosine (¹⁸F-FET) has been shown to be a useful tool for detecting TP and TRCs. Methods: We retrospectively evaluated 127 consecutive patients with World Health Organization grade II–IV glioma who underwent ¹⁸F-FET PET imaging to distinguish between TP and TRCs. ¹⁸F-FET PET findings were verified by neuropathology (40 patients) or clinicoradiologic follow-up (87 patients). Maximum tumor-to-brain ratios (TBR_max) of ¹⁸F-FET uptake and the slope of the time–activity curves (20–50 min after injection) were determined. The diagnostic accuracy of ¹⁸F-FET PET parameters was evaluated by receiver-operating-characteristic analysis and χ² testing. The prognostic value of ¹⁸F-FET PET was estimated using the Kaplan–Meier method. Results: TP was diagnosed in 94 patients (74%) and TRCs in 33 (26%). For differentiating TP from TRCs, receiver-operating-characteristic analysis yielded an optimal ¹⁸F-FET TBR_max cutoff of 1.95 (sensitivity, 70%; specificity, 71%; accuracy, 70%; area under the curve, 0.75 ± 0.05). The highest accuracy was achieved by a combination of TBR_max and slope (sensitivity, 86%; specificity, 67%; accuracy, 81%). However, accuracy was poorer when tumors harbored isocitrate dehydrogenase (IDH) mutations (91% in IDH-wild-type tumors, 67% in IDH-mutant tumors, P < 0.001). ¹⁸F-FET PET results correlated with overall survival (P < 0.001). Conclusion: In our neurooncology department, the diagnostic performance of ¹⁸F-FET PET was convincing but slightly inferior to that of previous reports.

在神经胶质瘤患者中，肿瘤进展（TP）和治疗相关变化（TRC）之间的区别仍然具有挑战性。对影像学改变进行分类的困难可能导致治疗延迟或不必要的中止。使用O-（2- ¹⁸ F-氟乙基）-1-酪氨酸（¹⁸ F-FET）的PET已被证明是检测TP和TRC的有用工具。方法：我们回顾性评估了连续的127例世界卫生组织II–IV级神经胶质瘤患者，他们接受了¹⁸ F-FET PET成像以区分TP和TRC。^18岁通过神经病理学（40例）或临床放射学随访（87例）验证了F-FET PET的发现。确定了¹⁸ F-FET摄取的_最大脑肿瘤比（TBR _max）和时间-活动曲线的斜率（注射后20-50分钟）。的诊断准确性¹⁸ F-FET PET参数是由接收器操作特征分析和评价χ ²测试。¹⁸ F-FET PET的预后价值使用Kaplan–Meier方法进行估算。结果： TP诊断为94例（74％），TRC诊断为33例（26％）。为了区分TP和TRC，接收器工作特性分析得出了最佳的¹⁸ F-FET TBR _max临界值为1.95（灵敏度为70％；特异性为71％；准确度为70％；曲线下面积为0.75±0.05）。通过结合TBR _max和斜率获得最高的准确性（灵敏度为86％；特异性为67％；准确性为81％）。但是，准确度为较差当肿瘤窝藏异柠檬酸脱氢酶（IDH）的突变（在91％IDH -wild型肿瘤，在67％的IDH -mutant肿瘤，P <0.001）。¹⁸ F-FET PET结果与总体生存率相关（P <0.001）。结论：在我们的神经肿瘤科，¹⁸ F-FET PET的诊断性能令人信服，但略逊于先前的报道。