Albert Nathalie L, Winkelmann Isabel, Suchorska Bogdana, Wenter Vera, Schmid-Tannwald Christine, Mille Erik, Todica Andrei, Brendel Matthias, Tonn Jörg-Christian, Bartenstein Peter, la Fougère Christian
Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Marchioninistr. 15, 81377, Munich, Germany.
Department of Neurosurgery, Ludwig-Maximilians-University Munich, Marchioninistr. 15, 81377, Munich, Germany.
Eur J Nucl Med Mol Imaging. 2016 Jun;43(6):1105-14. doi: 10.1007/s00259-015-3276-2. Epub 2015 Dec 15.
Current guidelines for glioma imaging by positron emission tomography (PET) using the amino acid analogue O-(2-[(18)F]fluoroethyl)-L-tyrosine ((18)F-FET) recommend image acquisition from 20-40 min post injection (p.i.). The maximal tumour-to-background evaluation (TBRmax) obtained in these summation images does not enable reliable differentiation between low and high grade glioma (LGG and HGG), which, however, can be achieved by dynamic (18)F-FET-PET. We investigated the accuracy of tumour grading using TBRmax values at different earlier time points after tracer injection.
Three hundred and fourteen patients with histologically proven primary diagnosis of glioma (131 LGG, 183 HGG) who had undergone 40-min dynamic (18)F-FET-PET scans were retrospectively evaluated. TBRmax was assessed in the standard 20-40 min summation images, as well as in summation images from 0-10 min, 5-15 min, 5-20 min, and 15-30 min p.i., and kinetic analysis was performed. TBRmax values and kinetic analysis were correlated with histological classification. ROC analyses were performed for each time frame and sensitivity, specificity, and accuracy were assessed.
TBRmax values in the earlier summation images were significantly better for tumour grading (P < 0.001) when compared to standard 20-40 min scans, with best results for the early 5-15 min scan. This was due to higher TBRmax in the HGG (3.9 vs. 3.3; p < 0.001), while TBRmax remained nearly stable in the LGG (2.2 vs. 2.1). Overall, accuracy increased from 70 % in the 20-40 min analysis to 77 % in the 5-15 min images, but did not reach the accuracy of dynamic analysis (80 %).
Early TBRmax assessment (5-15 min p.i.) is more accurate for the differentiation between LGG and HGG than the standard static scan (20-40 min p.i.) mainly caused by the characteristic high (18)F-FET uptake of HGG in the initial phase. Therefore, when dynamic (18)F-FET-PET cannot be performed, early TBRmax assessment can be considered as an alternative for tumour grading.
目前使用氨基酸类似物O-(2-[(18)F]氟乙基)-L-酪氨酸((18)F-FET)进行正电子发射断层扫描(PET)胶质瘤成像的指南推荐在注射后(p.i.)20 - 40分钟进行图像采集。在这些叠加图像中获得的最大肿瘤与本底评估值(TBRmax)无法可靠区分低级别和高级别胶质瘤(LGG和HGG)，然而，动态(18)F-FET-PET可以实现这一点。我们研究了在示踪剂注射后不同早期时间点使用TBRmax值进行肿瘤分级的准确性。
回顾性评估314例经组织学证实为原发性胶质瘤诊断的患者(131例LGG，183例HGG)，这些患者均接受了40分钟的动态(18)F-FET-PET扫描。在标准的20 - 40分钟叠加图像以及注射后0 - 10分钟、5 - 15分钟、5 - 20分钟和15 - 30分钟的叠加图像中评估TBRmax，并进行动力学分析。TBRmax值和动力学分析与组织学分类相关。对每个时间框架进行ROC分析，并评估敏感性、特异性和准确性。
与标准的20 - 40分钟扫描相比，早期叠加图像中的TBRmax值在肿瘤分级方面显著更好(P < 0.001)，早期5 - 15分钟扫描的结果最佳。这是由于HGG中的TBRmax更高(3.9对3.3；p < 0.001)，而LGG中的TBRmax几乎保持稳定(2.2对2.1)。总体而言，准确性从20 - 40分钟分析中的70%提高到5 - 15分钟图像中的77%，但未达到动态分析的准确性(80%)。
早期TBRmax评估(注射后5 - 15分钟)在区分LGG和HGG方面比标准静态扫描(注射后20 - 40分钟)更准确，这主要是由于HGG在初始阶段对(18)F-FET的特征性高摄取。因此，当无法进行动态(18)F-FET-PET时，早期TBRmax评估可被视为肿瘤分级的一种替代方法。
