Subcortical Brain Regions Associated With Seizure Risk in Patients With IDH Mutated Diffuse Gliomas

Seizure incidence in diffuse glioma ranges between 60% and 90%. This study aimed to investigate the association between seizures and diffuse glioma in subcortical and cortical brain regions, including white matter tracts.

Adult patients with diffuse glioma at Uppsala University Hospital from 2005 to 2021 were analysed retrospectively. The relationship between tumour location in specific brain voxels and preoperative seizures was examined concerning white matter tract involvement. Tumour volumes were segmented based on T2-weighted or FLAIR MRI after spatial normalisation to standard space (MNI) and combined to create a location-specific frequency map.

Of the 93 patients meeting the inclusion criteria, 70 (75%) experienced seizures. A significant decreased risk was found in tumours present within the left fronto-mesial and dorsal voxel (A3C1S1). Increased seizure risk was found in tumours located in the left supramarginal and posterior insular voxel (A4C2S3). The voxels differed in terms of type and extent of white matter networks. Additionally, there was a difference in seizure risk and voxel associations between oligodendrogliomas and astrocytoma, with specific voxels associated with seizures identified in both groups.

The study provides new insights into the epileptogenic potential of diffuse gliomas in relation to their spatial distribution, highlighting the need to analyse both cortical and subcortical localisation of tumours. The observed differences in seizure risks across brain regions underscore the need for personalised post-surgery treatment strategies and further research to understand the pathophysiology of brain tumour-related epilepsy, BTRE.