Evaluation of isocitrate dehydrogenase mutation in 2021 world health organization classification grade 3 and 4 glioma adult-type diffuse gliomas with 18F-fluoromisonidazole PET

Purpose: This study aimed to investigate the uptake characteristics of ¹⁸F-fluoromisonidazole (FMISO), in mutant-type isocitrate dehydrogenase (IDH-mutant, grade 3 and 4) and wild-type IDH (IDH-wildtype, grade 4) 2021 WHO classification adult-type diffuse gliomas.

Materials and methods: Patients with grade 3 and 4 adult-type diffuse gliomas (n = 35) were included in this prospective study. After registering ¹⁸F-FMISO PET and MR images, standardized uptake value (SUV) and apparent diffusion coefficient (ADC) were evaluated in hyperintense areas on fluid-attenuated inversion recovery (FLAIR) imaging (HIA), and in contrast-enhanced tumors (CET) by manually placing 3D volumes of interest. Relative SUV_max (rSUV_max) and SUV_mean (rSUV_mean), 10th percentile of ADC (ADC_10pct), mean ADC (ADC_mean) were measured in HIA and CET, respectively.

Results: rSUV_mean in HIA and rSUV_mean in CET were significantly higher in IDH-wildtype than in IDH-mutant (P = 0.0496 and 0.03, respectively). The combination of FMISO rSUV_mean in HIA and ADC_10pct in CET, that of rSUV_max and ADC_10pct in CET, that of rSUV_mean in HIA and ADC_mean in CET, were able to differentiate IDH-mutant from IDH-wildtype (AUC 0.80). When confined to astrocytic tumors except for oligodendroglioma, rSUV_max, rSUV_mean in HIA and rSUV_mean in CET were higher for IDH-wildtype than for IDH-mutant, but not significantly (P = 0.23, 0.13 and 0.14, respectively). The combination of FMISO rSUV_mean in HIA and ADC_10pct in CET was able to differentiate IDH-mutant (AUC 0.81).

Conclusion: PET using ¹⁸F-FMISO and ADC might provide a valuable tool for differentiating between IDH mutation status of 2021 WHO classification grade 3 and 4 adult-type diffuse gliomas.