Epileptogenic Zone with Focal Cortical Dysplasia in the Frontoparietal Lobe: A Voxel-Based Morphometry Analysis

Abstract Objective: The abnormal zone of the epileptogenic zone may explain the impact of focal epilepsy on more widespread brain networks involved in typical cognition and development. In some patients, seizures continue after surgery, interfering with accurate detection of potential preoperative zone. This study unraveled zone changes and mechanisms in the frontoparietal cortex of patients with focal cortical dysplasia (FCD) type IIb using voxel-based morphometric analysis before surgery. Methods : Three-dimensional magnetic resonance images were captured from 22 patients with histologically verified FCD type IIb in the frontoparietal lobe. Twenty-two healthy subjects constituted the control group. Voxel-based morphometry (VBM), xjView, and automated anatomical labeling atlas were used to calculate the volume alteration of the whole-brain gray matter by measuring the increment and decrement of gray matter cluster abnormalities. Results : A significant increase in gray matter clusters distributed mainly in the bilateral frontal gyrus, temporal gyrus, fusiform, several brain nuclei, and right cerebellum was observed in patients with FCD. Subtle changes were observed in the occipital gyrus, inferior parietal gyrus, paracentral and insular regions in the left hemisphere, hippocampus, parahippocampus, thalamic nuclei, and basal ganglia in the right hemisphere. The VBM results were concordant with the clinical findings. Conclusions : The VBM analysis established pre-evaluation and surgical strategies. The significant brain regions investigated using VBM potentially improve the prognosis of epilepsy surgeries after complete resection of the epileptogenic zone.