Prospective detection of cortical dysplasia on clinical MRI in pediatric intractable epilepsy

Predictive factors for seizure freedom after epilepsy surgery for pediatric low-grade tumors and focal cortical dysplasia

Epilepsy may be drug-resistant in a third of patients necessitating alternative treatments, such as surgery. Among refractory epilepsy patients, the most common etiologies are tumors and focal cortical dysplasia (FCD). Surgical management of tumor-related epilepsy has one of the highest rates of seizure freedom, whereas FCD represents some of the lowest success rates in epilepsy treatment. This study investigates the pre-operative characteristics associated with differences in postsurgical seizure outcomes in patients with FCD and tumors. We completed a retrospective cross-sectional review of epilepsy surgery patients with tumors (n = 29) or FCD (n = 44). Participants had a minimum medical follow-up at least 6 months after surgery (FCD M = 2.1 years; Tumors M = 2.0 years). Patients with FCD trended toward an earlier age of onset (t = -4.19, p = 0.058) and longer epilepsy duration (t = 3.75, p < 0.001). Epilepsy surgery is highly effective in reducing seizures in patients with FCD or tumors with over 70 % of all patients achieving seizure freedom. We found a higher rate of seizure freedom in patients with tumors than FCD, but this difference did not reach significance (79 vs. 66 %). Predictive factors of outcomes for FCD and tumors differ. Findings indicate that diagnostic tests may be differentially sensitive to patients with tumors, and future research is needed.

Presurgical Evaluation Strategies for Intractable Epilepsy of Childhood

For children who continue to experience seizures despite treatment with antiseizure medications, epilepsy surgery can be considered. The goals of the presurgical evaluation are to determine the best surgical approach to render a good outcome. In patients with drug resistant focal epilepsy, the epileptogenic zone defines the minimal brain volume which must be resected for surgical success and to delineate the relationship of this region with functional cortex. A number of noninvasive tools for these tasks have emerged over the past decade, and existing technologies have been revised and improved. In this review, we examine the recent published evidence for these techniques, specifically as applied to the pediatric population. Discussed herein are the diagnostic value of methods such as video electroencephalography, magnetic resonance imaging, and supportive neuroimaging techniques including single photon emission tomography, photon emission tomography, and magnetoencephalography. Functional testing including functional magnetic resonance imaging, electrical stimulation mapping, and transcranial magnetic stimulation are considered in the context of pediatric epilepsy. The application of emerging techniques to preoperative testing such as source localization, image post-processing, and artificial intelligence is covered. We summarize the relative value of presurgical testing based on patient characteristics, including lesional or nonlesional MRI, temporal or extratemporal epilepsy, and other factors relevant in pediatric epilepsy such as pathological substrate and age.

Morphometric analysis program: Detection of epileptic foci in young children using an adult normative database: Initial experience

Objective

To report our initial experience using an adult-template MAP in drug-resistant focal epilepsy in five children with apparently normal MRI.

Methods

Patients selected were highly suspicious of harboring focal structural lesions and had negative brain MRI studies. MAP was performed using a locally obtained adult database as a template. Results were reviewed by two neuroradiologists. Pertinence of MAP-positive areas was confirmed by the focal epileptic hypothesis or by pathology when possible (J Neuroradiol, 39, 2012, 87). Visual analysis was performed using Mango Software. MRI studies were reanalyzed at the workstation with knowledge of the clinical suspicion to confirm or discard the possibility of FCD.

Results

Five patients aged 19-48 months were studied, all with initial 3T MRI studies interpreted as normal. All had focal epileptic hypothesis with coherence of clinical seizure characterization and electroencephalographic findings. In two patients, histology showed type 1 FCD. Due to the age of our subjects, the junction map always highlighted the subcortical white matter in relationship to maturity differences. FCD was identified as asymmetric U-shaped highlighted regions in the junction map.

Significance

FCD is the most frequent pathology reported in pediatric epilepsy surgery series (Epileptic Disord, 18, 2016, 240). Significant number of FCDs may be overlooked on MRIs, reducing the odds of seizure freedom after surgery (Epilepsy Res, 89, 2010, 310). MAP is an image postprocessing method for enhanced visualization of FCD; however, when using an adult template in developing brains, normal subcortical regions may be highlighted as pathological. Creating a pediatric template is difficult, due to the need for general anesthesia to acquire the MRI database. Here, we were able to show that MAP identified FCDs as asymmetric "U-" shaped highlighted regions in the junction maps of all five patients, which may indicate that obtaining childhood databases for this purpose may not be necessary and that adult ones suffice for diagnosis of FCD.

WITHDRAWN: Analysis of Risk Factors for Prognosis and Infection of Child with Refractory Epilepsy Via Artificial Intelligence Neural Network Image Information

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Patient management conference: Correlating pre-surgical data

The epilepsy surgery patient management conference is a fundamental part of the presurgical evaluation. This article reviews the literature and describes a single center's approach. Case examples highlight how patient management conferences may influence clinical care.

Epilepsy prevalence and severity predictors in MRI-identified focal cortical dysplasia

OBJECTIVES

To determine the prevalence of epilepsy and drug-resistant epilepsy in pediatric patients with focal cortical dysplasia (FCD) identified by magnetic resonance imaging (MRI). To determine clinical and imaging differences between those with drug-resistant epilepsy, drug-responsive epilepsy, and no epilepsy among children with MRI-identified FCD.

METHODS

A keyword search of a hospital radiology database identified 97 study participants for inclusion in this retrospective study. Participants were included if they were under 18 years of age at time of database query and had an MRI between 2004 and 2013 showing FCD. Exclusion was based on imaging and clinical characteristics. Data was gathered using a chart review and supplemental questionnaire.

RESULTS

In this cohort of patients with imaging findings compatible with FCD, 29% had not developed epilepsy. The prevalence of epilepsy and drug-resistant epilepsy was 71.13% (95% C.I.=61.05-79.89%) and 32.99% (95% C.I.=23.78-43.27%), respectively. Patients with epilepsy were more likely to have temporal (p=0.029) or frontal (p=0.044) lobe lesions and a family history of seizures (p=0.003) than those without epilepsy. Age of seizure onset was later in those with drug-responsive epilepsy than those with drug-resistant epilepsy (p=0.0002). A later age of seizure onset (OR=1.22, p=0.0441, 95% C.I.=1.00-1.486) and absence of developmental delay (OR=3.624, p=0.0497, 95% C.I.=1.002-13.110) predicted a less severe epilepsy phenotype.

CONCLUSIONS

Previous studies have only assessed patient cohorts with FCD and epilepsy, limiting the data on "asymptomatic" or "atypically presenting" FCD. Identifying a surprisingly large, novel cohort of children with FCD that had not developed epilepsy helps define prognosis and inform clinical management of children with FCD on imaging.