IDH1 and oligodendroglioma: Quantitative longitudinal studies of imaging growth patterns in patients with IDH-mutant glioma have confirmed the continuous tumor growth without treatment and established correlations with molecular status.49,62–64 Growth was slower in IDH-mutant and 1p/19q-codeleted oligodendroglioma than in IDHmt astrocytomas, and was also slower in grade 2 IDH-mutant and 1p/19q-oligodendroglioma codeleted than in grade 3 oligodendroglioma, IDH-mutant and 1p/19q-codeleted.49,62 Similarly, TGR correlated with grade in IDH-mutant astrocytoma (grades 4 > 3 > 2).