Prediction of Pharmacoresponsiveness in Focal Cortical Dysplasia with Magnetic Resonance Imaging

Abstract

Background: Focal cortical dysplasia (FCD) is a common cause of intractable epilepsy in children and adolescents. Clinical features vary broadly, including treatment response. The aim of this study was to identify specific magnetic resonance imaging (MRI) features that could be used to predict pharmacoresponsiveness in FCD patients. Methods: We retrospectively reviewed brain MRI scans of 76 children and adolescents who had a lesion consistent with FCD, which correlated with focal onset epilepsy. Pharmacoresponsiveness was defined as a 2-year seizure-free period while receiving antiepileptic drugs. MRI features were compared between a pharmacoresponsive and pharmacoresistant group. Patients were categorized into 4 groups according to their MRI features, such as the severity of gray-white matter boarder blurring, lesion location, and signal changes on T2-weighted images. Clinical outcomes, including responses to the antiepileptic drugs were compared between these groups. Results: Twenty-four patients (31.6%) responded well to the antiepileptic drugs, while 52 patients showed resistance. Localized signal changes were more frequently found in the pharmacoresponsive group in comparison to the pharmacoresistant group (70.8% vs. 38.5%, respectively, p = 0.013). In contrast, diffuse signal changes were more common among the patients with pharmacoresistance (25% vs. 8.3%, respectively, p = 0.028). When FCD were categorized into 4 subtypes according to their MRI features, diffuse type with low/iso cortical signal intensities had an earlier age-of-onset and a lower full-scale IQ compared to other subtypes. Conclusions: This study suggests that FCD patients may respond variously to antiepileptic medication. The extent of the lesion, distinguishable by signal changes, may be related to the pharmacoresponsiveness.