Structural plasticity of the contralesional subfields of hippocampus and amygdala in patients with IDH-mutant astrocytoma and oligodendroglioma.

Purpose: To detect the structural plasticity of the contralesional hippocampus and amygdala in patients with unilateral IDH-mutant astrocytoma and oligodendroglioma, and to compare the differences between these two types of tumors.

Methods: 3D T1-weighted MRI images were collected from 46 patients with left-hemispheric tumors (IDH-mutant astrocytoma, n = 22; oligodendroglioma, n = 24) and 23 healthy controls (HCs). Volumetric differences in the subregional volumes of the hippocampus and amygdala were assessed using FreeSurfer software. The differences were compared across groups.

Results: In comparison to HCs, patients with unilateral IDH-mutant astrocytoma and oligodendroglioma exhibited a significantly larger volume of the hippocampal fissure in the contralesional hippocampus (p = 0.021, p = 0.041). In the astrocytoma group, volumetric increases were also observed in the contralesional amygdala subregions, including the medial-nucleus (p = 0.009), central-nucleus (p = 0.011), and cortical-nucleus (p = 0.039). Compared to the oligodendroglioma group, the astrocytoma group demonstrated significantly larger gray matter volume in the subiculum head (p = 0.008) of the contralesional hippocampus, as well as in the anterior amygdaloid area (AAA) (p = 0.044), central-nucleus (p = 0.025), and cortical-nucleus (p = 0.021) of the contralesional amygdala.

Conclusion: These findings provide robust evidence of macrostructural plasticity in the contralateral hippocampus and amygdala in patients with unilateral IDH-mutant astrocytomas and oligodendrogliomas. Furthermore, the structural differences between tumor types may reflect distinct effects on brain plasticity and variations in tumor invasiveness. These insights could contribute to optimization of clinical management strategies and personalized cognitive rehabilitation strategies for glioma patients.