背景：假性进展（PSP）的及时检测对于高级别神经胶质瘤（HGG）患者的治疗至关重要，但仍然很困难。O-（2-[18F]氟乙基）-L-酪氨酸正电子发射断层扫描（FET-PET）的结构特征反映了肿瘤的摄取异质性；其中一些可能与肿瘤进展有关。
方法：14例疑似PSP的HGG患者接受了FET-PET显像。对一组19个常规和纹理FET-PET特征进行了评估，并进行了无监督的共识聚类。真正进展的最终诊断与PSP基于使用RANO标准的随访MRI。
结果:已经基于10个主要的纹理FET-PET特征确定了三个稳健的簇。PSP患者均未落入第2组，这与摄取异质性的纹理FET-PET标志物的高值相关。4名PSP患者中有3名被分配到第3组，这在很大程度上与纹理FET-PET特征的低值相关。相比之下,在最佳截止值2.1时，肿瘤与正常脑比率（TNRmax）对PSP的预测较低（检测真实进展的阴性预测值为57％，p=0.07vs.75%，簇3，p=0.04)。
结论：基于结构O-（2-[18F]氟乙基）-L-酪氨酸PET特征的聚类可能为评估伪进展的难以捉摸的现象提供有价值的信息。
BACKGROUND: Timely detection of pseudoprogression (PSP) is crucial for the management of patients with high-grade glioma (HGG) but remains difficult. Textural features of O-(2-[18F]fluoroethyl)-L-tyrosine positron emission tomography (FET-PET) mirror tumor uptake heterogeneity; some of them may be associated with tumor progression.
METHODS: Fourteen patients with HGG and suspected of PSP underwent FET-PET imaging. A set of 19 conventional and textural FET-PET features were evaluated and subjected to unsupervised
consensus clustering. The final diagnosis of true progression vs. PSP was based on follow-up MRI using RANO criteria.
RESULTS: Three robust clusters have been identified based on 10 predominantly textural FET-PET features. None of the patients with PSP fell into cluster 2, which was associated with high values for textural FET-PET markers of uptake heterogeneity. Three out of 4 patients with PSP were assigned to cluster 3 that was largely associated with low values of textural FET-PET features. By comparison, tumor-to-normal brain ratio (TNRmax) at the optimal cutoff 2.1 was less predictive of PSP (negative predictive value 57% for detecting true progression, p=0.07 vs. 75% with cluster 3, p=0.04).
CONCLUSIONS: Clustering based on textural O-(2-[18F]fluoroethyl)-L-tyrosine PET features may provide valuable information in assessing the elusive phenomenon of pseudoprogression.
