Multiple Positron Emission Tomography Tracers for Use in the Classification of Gliomas According to the 2016 World Health Organization Criteria

Background. The molecular diagnosis of gliomas such as isocitrate dehydrogenase (IDH) status (wild-type [wt] or mutation [mut]) is especially important in the 2016 World Health Organization (WHO) classification. Positron emission tomography (PET) has afforded molecular and metabolic diagnostic imaging. The present study aimed to define the interrelationship between the 2016 WHO classification of gliomas and the integrated data from PET images using multiple tracers, including F-18-fluorodeoxyglucose (F-18-FDG), C-11-methionine (C-11-MET), F-18-fluorothymidine (F-18-FLT), and F-18-fluoromisonidazole (F-18-FMISO). Methods. This retrospective, single-center study comprised 113 patients with newly diagnosed glioma based on the 2016 WHO criteria. Patients were divided into 4 glioma subtypes (Mut, Codel, Wt, and glioblastoma multiforme [GBM]). Tumor standardized uptake value (SUV) divided by mean normal cortical SUV (tumor-normal tissue ratio [TNR]) was calculated for F-18-FDG, C-11-MET, and F-18-FLT. Tumor-blood SUV ratio (TBR) was calculated for F-18-FMISO. To assess the diagnostic accuracy of PET tracers in distinguishing glioma subtypes, a comparative analysis ofTNRs andTBR as well as the metabolic tumor volume (MTV) were calculated by Scheffe's multiple comparison procedure for each PET tracer following the Kruskal-Wallis test. Results. The differences in mean F-18-FLT TNR and F-18-FMISO TBR were significant between GBM and other glioma subtypes (P <.001). Regarding the comparison between Gd-T1WI volumes and F-18-FLT MTVs or F-18-FMISO MTVs, we identified significant differences between Wt and Mut or Codel (P <.01). Conclusion. Combined administration of 4 PET tracers might aid in the preoperative differential diagnosis of gliomas according to the 2016 WHO criteria.