Gross tumor volume imaging: comparison of MRI, FET-PET and perfusion MRI in patients with recurrent glioblastoma

Abstract: GBM is the most common and aggressive histologic type of glial tumors. The standard treatment is surgery, radiation therapy and chemotherapy. The gross target volume (GTV) for radiotherapy may be determined with FET-PET or contrast enhanced MRI. Generally, diagnosis, treatment planning and follow-up of GBM are based on MRI, however conventional MRI has a limitation, the inability to differentiate tumor progression from treatment related changes, while FET-PET has been proven capable to non-invasively differentiate treatment-related changes from tumor progression. Similarly, an increased rCBV with leakage correction in DSC perfusion, as an additional parameter to conventional MRI, can indicate a real tumor, while rCBV is not increased in case of pseudoprogression. The primary objective of this retrospective study is comparison of spatial differences of the GTV between contrast enhanced T1-MP-RAGE, FET-PET and corrected rCBV for radiotherapy. At the same time we have evaluated, if leakage corrected rCBV in addition to contrast enhanced MRI can improve the diagnostic performance of recurrent GBM. This work is a sub-study of the GLIAA study that addresses evaluation of radiotherapy target volume delineation by amino acid PET and its effects on prolonged survival in comparison with contrast-enhanced MRI in patients with recurrent GBM. We have evaluated retrospectively the data of 36 patients from GLIAA with recurrent GBM, who had undergone radio-chemotherapy, and we have compared spatial differences of GTV between contrast enhanced MRI, perfusion MRI and FET-PET. DSC perfusion images were processed using the leakage correction algorithm implemented in syngo.via. GTV were semiautomatically segmented and co-registered in the imaging software NORA. Our results indicated that median GTV were significantly larger in FET-PET compared to contrast enhanced MP-RAGE and DSC MRI sequences. Median recurrent GTV were 12.2, 6.1, and 4.4 ml, respectively. Delta-GTV between FET-PET and MP-RAGE were 4.8 ± 3.8 ml, between MP-RAGE and DSC perfusion 3.6 ± 8.1 ml and between FET-PET and DSC perfusion 8.4 ± 7.9 ml. Many other studies obtained very similar results. In our study more than 94% patients with glioblastoma recurrence show increased rCBV in case of a contrast-enhanced real tumor. Additionally, we could demonstrate in two of the 36 patients very small parts of tumor first detectable in contrast enhanced MRI and DSC perfusion, and a few months later FET-PET shows also increased accumulation in the sense of a tumor recurrence. Due to some limitations for evaluating the perfusion MRI and heterogeneity, among other studies in post-processing of DSC perfusion, additional studies would be required to obtain more robust results. Standardized FET-PET evaluations (using a SUV of 1.8) display larger GTV than contrast-enhanced MP-RAGE scans. Different GTV and thus irradiation volumes may affects the clinical outcome. Even with leakage correction DSC images are not suited for GTV evaluation

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Universität Freiburg, Dissertation, 2024

Classification and Topics

• Keyword: Kernspintomografie ; Hirntumor ; Computertomografie ; Hirnkrankheit ; Tumor ; Glioblastom ; Rezidiv

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2024
• Creator: Wendeberg, Maryam
• Contributor: Urbach, Horst ; Grosu, Anca-Ligia ; Coenen, Volker Arnd ; Klinik für Neuroradiologie ; Albert-Ludwigs-Universität Freiburg. Medizinische Fakultät

Further information

• DOI: 10.6094/UNIFR/256880
• URN: urn:nbn:de:bsz:25-freidok-2568804
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:23 AM CEST