Mapping Epileptogenic Tissues in MRI-Negative Focal Epilepsy

In patients with drug-resistant focal epilepsy, pathologies such as focal cortical dysplasia (FCD), hippocampal sclerosis, polymicrogyria, or ganglioglioma typically appear as structural lesions on MRI. Mapping these structural lesions is fundamental to planning epilepsy surgery for controlling seizures. These lesions are part of the epileptogenic zone, and their incomplete removal is associated with seizure recurrence. A major diagnostic challenge occurs when patients with focal epilepsy do not have demonstrable lesions on MRI.1 The surgical outcomes in these patients are considerably less favorable if their pathology is missed by traditional visual inspection.