Brain regions associated with frequent occurrences of seizures related to low-grade gliomas: a voxel-level evidence

Background Tumor location has been demonstrated to influence the risk of epilepsy in patients with low-grade gliomas (LGGs). However, existing evidence is mainly based on dichotomized analyses, without adequately accounting for seizure frequency. We present a voxel-wise lesion analysis to investigate the potential correlations between the location of tumor and the frequency of seizure occurrence in patients with LGGs. Methods We retrospectively reviewed the clinical information and magnetic resonance images of 352 patients pathologically confirmed with LGGs. Preoperative seizure frequency during the 3 months prior to the primary surgery was classified as daily (≥1/day), weekly (≥1/week), monthly (≥1/month) and rare (<1/month). A voxel-based lesion-symptom mapping analysis was performed to identify the association between tumor location and preoperative seizure frequency. Results LGGs involving the left primary motor area or right insular and basal ganglia were associated with an increased risk of frequent seizures (≥1/month). A focal aware seizure was more likely to frequently occur compared with a focal to bilateral tonic–clonic seizure caused by LGGs ( p < 0.001). Tumors that caused a high seizure frequency were less likely to be completely removed ( p = 0.008). Furthermore, preoperative seizure frequency was a significant predictor of seizure outcomes at 6 months after surgery as determined by a univariate analysis ( p = 0.002). Conclusion This study utilized voxel-level neuroimaging analyses to identify the anatomical correlations of seizure frequency in patients with LGGs, providing further insight into seizure risk stratification and potential implications for surgical management.