MRI supersedes ictal EEG when other presurgical data are concordant

Area of Science:

• Pediatric Neurology
• Epileptology
• Neurosurgery

Background:

• Epilepsy surgery relies on accurate localization of the epileptogenic zone.
• Discrepancies between electroencephalography (EEG) and magnetic resonance imaging (MRI) findings pose challenges in surgical planning.
• The role of ictal EEG in guiding surgical decisions when discordant with other presurgical data is debated.

Purpose of the Study:

• To compare surgical outcomes in pediatric epilepsy patients with MRI lesions.
• To evaluate the impact of discordant versus concordant ictal EEG findings on seizure-free outcomes.
• To assess the prudence of proceeding with surgery based on MRI when ictal EEG is discordant.

Main Methods:

• Retrospective study of 115 children undergoing epilepsy surgery for MRI-identified lesions.
• Classification of ictal EEG as 'positive' (concordant) or 'negative' (discordant) with MRI and other presurgical data.
• Comparison of seizure-free outcomes at 2 years between the two EEG groups.

Main Results:

• Seizure-free outcomes were similar between positive ictal EEG (73%) and negative ictal EEG (80%) groups.
• Positive ictal EEG did not improve outcomes regardless of surgical site or lesion pathology.
• Ictal EEG, with a 73% positive predictive value, provided no additional benefit in this cohort (77% overall seizure-free rate).

Conclusions:

• In pediatric epilepsy surgery patients with MRI lesions and concordant data, ictal EEG has limited predictive value.
• The additive role of ictal recordings in patients with concordant MRI and presurgical data warrants re-evaluation.
• Surgical decisions may not require ictal EEG concordance when other data strongly support an MRI-identified lesion.