Structural plasticity of the contralesional hippocampus and its subfields in patients with glioma

ObjectivesTo characterize the structural plasticity of the contralesional hippocampus and its subfields in patients with unilateral glioma.Methods3D T1-weighted MRI images were collected from 55 patients with tumors infiltrating the left (HipL, n = 27) or right (HipR, n = 28) hippocampus, along with 30 age- and sex-matched healthy controls (HC). Gray matter volume differences of the contralesional hippocampal regions and three control regions (superior frontal gyrus, caudate nucleus, and superior occipital gyrus) were evaluated using voxel-based morphometry (VBM) analyses. Volumetric differences in the hippocampus and its subregional volume were measured using the FreeSurfer software.ResultsCompared with HC, patients with unilateral hippocampal glioma exhibited significantly larger gray matter volume in the contralesional hippocampus and parahippocampal regions (cluster = 571 voxels for HipL; cluster 1 = 538 voxels and cluster 2 = 88 voxels for HipR; family-wise error corrected p < 0.05). No significant alterations were found in control regions. Volumetric analyses showed the same trend in the contralesional hippocampal subregions for both patient groups, including the CA1 head, CA3 head, hippocampus amygdala transition area (HATA), fimbria, and the granule cell molecular layer of the dentate gyrus head (GC-ML-DG head). Notably, the differences of the contralesional HATA (HipL: eta(2) = 0.418, corrected p = 0.002; HipR: eta(2) = 0.313, corrected p = 0.052) and fimbria (HipL: eta(2) = 0.450, corrected p < 0.001; HipR: eta(2) = 0.358, corrected p = 0.012) still held after the Bonferroni correction.ConclusionsOur findings provide evidence for macrostructural plasticity of the contralateral hippocampus in patients with unilateral hippocampal glioma. Specifically, HATA and fimbria exhibit great potential in this process.

Automated summary

The study aims to characterize the structural plasticity of the contralesional hippocampus and its subfields in patients with unilateral glioma. The results showed significantly larger gray matter volume in the contralesional hippocampus and parahippocampal regions, while no significant alterations were found in control regions. The volumetric analyses also revealed similar trends in the contralesional hippocampal subregions for both patient groups.