الفهرس 
Review of literatureOnly 14 pages are availabe for public view
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Abstract
Epilepsy is the considered the most common neurological pediatric disease.1 In children, uncontrolled ongoing seizures has been shown to be associated with developmental delay and cognitive decline. Improvement in the developmental outcome may be noted with early cessation of seizures.2 Approximately, 25% percent of patients are refractory to medical therapy, many of them may get benefit from neurosurgeries.3
Patients suffering from epilepsy are frequently evaluated with neuroimaging aiming to detect the cause of seizures which may lead to proper management. The decision to perform neuroimaging depends on some factors such as the age at the seizure onset, type of seizure, result of neurologic exam and electroencephalogram (EEG) findings.4
The most common causes of drug-resistant epilepsy in childhood are focal malformations of cortical development (MCD) and low-grade tumors. These two diagnoses make up 90% of the cases of intractable epilepsy in infants, 70% in preadolescent children, and 57% in adolescents. 5-7
Other causes include hippocampal sclerosis, which is sometimes associated with such extrahippocampal diseases, such as low-grade tumors or focal cortical dysplasia (FCD) “FCD type IIIa”.8 Cerebral cavernous malformatio0ns (CCM) are estimated to represent around 30% of pediatric causes of drug-resistant epilepsy.9,10. Furthermore, seizures are a common symptom of supratentorial arteriovenous malformations (AVM).11
Advances in neuroimaging helped in choosing an increasing number of children with drug-resistant epilepsy into the pediatric epilepsy surgery programs. Surgical resection of the so-called epileptogenic zone (EZ) as a treatment for epilepsy is a well-established and rapidly evolving technique for treating pediatric drug-resistant epilepsy.12-14 Epilepsy surgery in children who have been carefully chosen can markedly improve the postoperative seizure outcome in nearly 60% of the children with drug-resistant seizures.5,6
Despite recent technological advances, delineation of the EZ remains challenging for epilepsy surgeons, especially in poorly-defined pathologies where the lesion is thought to extend beyond the visible margins on the MRI, or does not have distinct borders, such as in FCD or tuberous sclerosis (TS). Efforts are focused on better visualizing and achieving complete resection of the EZ toward improving the outcomes of epilepsy surgeries.15
Intraoperative MRI (ioMRI) has been integrated into the neurosurgical practice with good results. Indeed, wider and more accurate tumor resections can be achieved using ioMRI in tumor surgeries, and its usage is associated with higher survival rates.16,17 Previous reports have also suggested that ioMRI led to increased rates of GTR and postoperative seizure freedom in MCD surgeries and fewer neurological complications.18,19
Despite this background knowledge, questions may remain about the efficacy of ioMRI for the pediatric epilepsy surgery, as there are only few reports in literature were done on the pediatric population. The current follow-up study aims to determine how ioMRI affects the percentage of postoperative residual volumes, and if the residual lesion volume affects seizure outcomes in children undergoing epilepsy surgeries.