18F-FET PET Imaging in Differentiating Glioma Progression from Treatment-Related Changes: A Single-Center Experience: A Single-Center Experience

Gabriele D. Maurer*, Daniel P. Brucker, Gabriele Stoffels, Katharina Filipski, Christian P. Filss, Felix M. Mottaghy, Norbert Galldiks, Joachim P. Steinbach, Elke Hattingen, Karl-Josef Langen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


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 χ 2 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.

Original languageEnglish
Pages (from-to)505-511
Number of pages7
JournalJournal of Nuclear Medicine
Issue number4
Publication statusPublished - 1 Apr 2020


  • F-18-FET PET
  • glioma
  • tumor progression
  • pseudoprogression
  • treatment-related changes
  • MRI

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