IDH1 and glioblastoma: No specific neuroimaging features have been identified that reliably distinguish H3 G34-mutant diffuse hemispheric gliomas from adult types of high-grade diffuse gliomas, notably IDH-wildtype glioblastoma.15–18 As H3 G34-mutant diffuse hemispheric gliomas are rare tumors, data on patient outcomes are limited to small patient cohorts.