Aggressive WHO grades III and IV and IDH-wildtype gliomas were dominated by a high proportion of voxels with an early peak, negative slope, and high TBR, whereby the PVHs with TTP < 20 min p.i., Slope15–40 < 0 SUV/h, and TBR5–15 and TBR20–40 > 2 yielded the most significant differences between glioma grades. This evidence concerns the gene IDH1 and central nervous system cancer.