Combined impact of grey and superficial white matter abnormalities: implications for epilepsy surgery
Journal:
arXiv
Published Date:
Mar 17, 2025
Abstract
Drug-resistant focal epilepsy is associated with abnormalities in the brain
in both grey matter (GM) and superficial white matter (SWM). However, it is
unknown if both types of abnormalities are important in supporting seizures.
Here, we test if surgical removal of GM and/or SWM abnormalities relates to
post-surgical seizure outcome in people with temporal lobe epilepsy (TLE).
We analyzed structural imaging data from 143 TLE patients (pre-op dMRI and
pre-op T1-weighted MRI) and 97 healthy controls. We calculated GM volume
abnormalities and SWM mean diffusivity abnormalities and evaluated if their
surgical removal distinguished seizure outcome groups post-surgically.
At a group level, GM and SWM abnormalities were most common in the
ipsilateral temporal lobe and hippocampus in people with TLE. Analyzing both
modalities together, compared to in isolation, improved surgical outcome
discrimination (GM AUC = 0.68, p < 0.01, WM AUC = 0.65, p < 0.01; Union AUC =
0.72, p < 0.01, Concordance AUC = 0.64, p = 0.04). Additionally, 100% of people
who had all concordant abnormal regions resected had ILAE$_{1,2}$ outcomes.
These findings suggest that regions identified as abnormal from both
diffusion-weighted and T1-weighted MRIs are involved in the epileptogenic
network and that resection of both types of abnormalities may enhance the
chances of living without disabling seizures.
