Conventional MRI/CT for differentiation of IDH-mutant adult-type diffuse gliomas: revisited with a new imaging feature “scFLAIR-D”

A refined T2FM definition improves sensitivity for AST while preserving high specificity. scFLAIR-D serves as a simple, specific marker of ODG; in combination, these routine features yield high rule-in specificity to support presurgical planning and early therapeutic counseling. Refining T2FM to include partial but exclude subcortical-only mismatch increased sensitivity for astrocytoma, IDH-mutant (87.5%) while preserving specificity (80.0%). Newly defined scFLAIR-D was highly specific for oligodendroglioma, IDH-mutant and 1p/19q-codeleted (93.8%). Combining these qualitative MRI/CT features yielded high rule-in specificities for lineage discrimination.