Neuroimaging in identifying focal cortical dysplasia and prognostic factors in pediatric and adolescent epilepsy surgery

Purpose: The purpose of this study is to determine the sensibility of each imaging tool in identifying focal cortical dysplasia (FCD) in children and adolescents with epilepsy and to define the prognostic factors of pediatric and adolescent epilepsy surgery. Methods: We identified 48 children with FCD who underwent resective surgery and analyzed their preoperative data. The results of various anatomic and functional neuroimaging studies were compared for accuracy in locating the lesion. We also investigated clinical factors that affected the outcome of surgical treatment. Key Findings: Brain magnetic resonance imaging (MRI) was able to localize FCD in 30 patients and fluorodeoxyglucose positron emission tomography (FDG-PET) and/or subtraction ictal single photon emission computed tomography (SPECT) coregistered with MRI provided additional information that helped to define the lesion in 13 patients. When comparing the pathologic results between a mild malformation of cortical development (MCD) and FCD type I and II, we noted a strong tendency for patients with FCD to have MRI abnormalities (p = 0.005). In addition, severe pathologic features (Palmini's classification, FCD type II) (p = 0.025) showed significant correlation with a better surgical outcome. To define the primary epileptogenic area, various interictal epileptiform discharges and the results of multimodal neuroimaging studies were helpful, and younger age at the time of operation could aid in more favorable surgical outcomes (p = 0.048). Significance: Our study showed a significant relationship between pathologic grade and the detectability of FCD by brain MRI. In addition, early surgery can be justified by showing that advanced neuroimaging studies in children with FCD and even with extensive epileptiform discharges have a higher rate of success.