Abstracts

Rationale: Pharmacoresistant epilepsy has a significant impact on the medical, neuro-psychological and psychosocial wellbeing of affected children. The impact of repetitive seizures in children may be more severe than in that experienced by the adult population because motor, sensorineural and cognitive functions are still developing in children. Still, the potential for recovery in children is greater than in that of adults because of increased cerebral plasticity in children. It has been recommended that surgical intervention be explored after the trial of two appropriately chosen anti-epileptic medications are utilized unsuccessfully.The potential for functional impairment may be a major limiting factor in proceeding with surgery for some children. Minimizing this potential risk while concurrently destroying the epileptogenic foci through minimally invasive means is optimal. This could be achieved in some individuals by utilizing ablation techniques such as Laser Ablation. Specifically, Thermal Ablation uses laser-induced heat to ablate neural tissue with limited surrounding damage. This study set out to evaluate the efficacy of SPECT and MEG in localizing a seizure focus in pediatric pharmacoresistant epilepsy and provide a direction comparison to the site of Laser Ablation.   Methods: The SPECT scans, MEG data, and clinical data of patients admitted to the EMU at Dell Children’s Hospital between the dates of:  July 2010 and January 2015 were retrospectively reviewed. This information was gathered in order to further delineate the patients who had undergone laser ablation surgery. The laser ablation data was cross-referenced with SPECT/SISCOM and MEG data in order to determine the efficacy in lateralizing and localizing the epileptogenic zone. In addition, the median level of concordance obtained for each of the modalities to compare the specificity of each modality. The levels of concordance were hemispheric, lobar, sub-lobar, and gyral.  Results: There were 6 cases of laser ablation that underwent both MEG and SPECT.  Laterality was concordant in most patients. 3/6 patients showed direct concordance of the SISCOM site while MEG showed direct concordant with 2/6. The median level of concordance for both MEG and SPECT when compared against each other 1.5 for MEG and 2 for SPECT.  A T-Test was conducted between SPECT and MEG but the test did not reveal a 90% confidence interval of difference between MEG and SPECT localization and lateralization of the focal onset zone. This was likely due to the small sample size. There was a trend observed that demonstrated SPECT having higher localization values of these deep-seated foci. Conclusions: This study revealed that when correlating the data between neuroimaging modalities, SPECT demonstrated a trend of having better localization value but results are not statistically significant. For deep regions of ictal onset, where ablation may negate damage of overlying normal cortex, both SISCOM and MEG may be helpful in identifying the region of seizure onset. Further studies are required for a more robust comparison. Funding: None