%0 Journal Article
%T Noninvasive Approach to Focal Cortical Dysplasias: Clinical, EEG, and Neuroimaging Features
%A Gustavo Seifer
%A Alejandro Blenkmann
%A Juan Pablo Princich
%A Dami¨¢n Consalvo
%A Cristina Papayannis
%A Carlos Muravchik
%A Silvia Kochen
%J Epilepsy Research and Treatment
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/736784
%X Purpose. The main purpose is to define more accurately the epileptogenic zone (EZ) with noninvasive methods in those patients with MRI diagnosis of focal cortical dysplasia (FCD) and epilepsy who are candidates of epilepsy surgery. Methods. Twenty patients were evaluated prospectively between 2007 and 2010 with comprehensive clinical evaluation, video-electroencephalography, diffusion tensor imaging (DTI), and high-resolution EEG to localize the equivalent current dipole (ECD). Key Findings. In 11 cases with white matter asymmetries in DTI the ECDs were located next to lesion on MRI with mean distance of 14.63£¿millimeters with topographical correlation with the EZ. Significance. We could establish a hypothesis of EZ based on Video-EEG, high-resolution EEG, ECD method, MRI, and DTI. These results are consistent with the hypothesis that the EZ in the FCD is complex and is often larger than visible lesion in MRI. 1. Introduction Drug-resistant epilepsy is associated with malformations of cortical development (MCD) in 15¨C20% of adult cases and in more than 50% of pediatric patients [1¨C3]. MCD are a heterogeneous group of focal and diffuse anatomical derangements whose pathological features depend largely on the timing of the defect in the developmental process and to a lesser extent on its cause [4, 5]. Focal cortical dysplasia (FCD) is the most frequent type of MCD. Taylor et al. (1971) were the first to describe them as focal anomalies of cortical structure [6]. Numerous classifications of FCD have been proposed; a consensus clinic-pathological classification has been recently published [7]. However, it is widely recognized that existing classifications are unsatisfactory to define a prognosis [8, 9]. Furthermore, the etiology of these abnormalities is often uncertain and the mechanisms generating epilepsy are also unclear [10]. Several studies reported that FCD are intrinsically epileptogenic and most patients often present drug resistant epilepsy [11¨C16]. Some authors described the epileptogenic zone (EZ) as focal [17], while others suggest a more complex network extending beyond the lesion, an ¡°epileptogenic network¡± [18]. Resective surgery is frequently a promising therapy in this population. However, the outcome following surgical treatment of these patients has been less successful than in other pathologies such as hippocampal sclerosis, even if the entire magnetic resonance images (MRIs) visible lesion is removed [19]. The surgical failure in these patients may be due to the difficulty in defining the epileptogenic zone, which can be more extensive
%U http://www.hindawi.com/journals/ert/2012/736784/