Dedicated Magnetic Resonance Imaging Sequences:Contribution in the Diagnosis of Focal Epilepsy in the Lebanese Population

There have been many advances in the diagnosis and management of focal epilepsies particularly with neuroimaging techniques and magnetic resonance imaging(MRI).Special MRI sequences can be employed to localize and resect the epileptogenic lesions responsible for focal epilepsy.This study aims to show the benefit of dedicated epilepsy MRI sequences in the diagnosis of focal epilepsies.A general electric 1.5 Tesla MRI machine was used with standard and special sequences.Also,a Nihon Kohden electroencephalography(EEG)machine was used.This is a prospective observational study that included 51 patients with focal epilepsies who had an initial negative brain imaging.They underwent epilepsy MRI sequences along with a prolonged video EEG monitoring to localize the lesion,and then results were analyzed statistically using SPSS 22 program.The majority of patients were males(62.75%)with a mean age of 30 years.The grand majority of patients(74.5%,p value of 0.001)had their lesion localized by the epilepsy MRI.The most commonly found pathology was mesial temporal sclerosis.A significant number of patients(23.5%)were sent for an epilepsy surgery(p value 0.002).This study shows the significant impact of dedicated epilepsy MRI sequences on the diagnosis and management of focal epilepsy in the Lebanese population.

Clinical Application of SPECT to the Localization of Corticoepileptogenic Focus of Intractable Epilepsy

This paper presented 51 cases of intractable epilepsy, of which 36 were males, and 15 females,with a mean age of 21. They were all verified through CT/MRI, among which 17 were proved to have lesions on the brain, and 34 to bave no lesion. Before operation all the patients were identified by SPECT and cerebral blood flow imaging (CBF). During the operation they were monitored under subdural strip electrode ECoG for the localization of corticoepileptogenic focus. The results showed that the sensitivity rate of localization with SPECT for corticoepileptogenic focus location was 97.87 %.

Interictal Electrophysiological Source Imaging Based on Realistic Epilepsy Head Model in Presurgical Evaluation:A Prospective Study

Invasive techniques are becoming increasingly important in the presurgical evaluation of epilepsy.Adopting the electrophysiological source imaging(ESI)of interictal scalp electroencephalography(EEG)to localize the epileptogenic zone remains a challenge.The accuracy of the preoperative localization of the epileptogenic zone is key to curing epilepsy.The T1 MRI and the boundary element method were used to build the realistic head model.To solve the inverse problem,the distributed inverse solution and equivalent current dipole(ECD)methods were employed to locate the epileptogenic zone.Furthermore,a combination of inverse solution algorithms and Granger causality connectivity measures was evaluated.The ECD method exhibited excellent focalization in lateralization and localization,achieving a coincidence rate of 99.02%(p<0.05)with the stereo electroencephalogram.The combination of ECD and the directed transfer function led to excellent matching between the information flow obtained from intracranial and scalp EEG recordings.The ECD inverse solution method showed the highest performance and could extract the discharge information at the cortex level from noninvasive low-density EEG data.Thus,the accurate preoperative localization of the epileptogenic zone could reduce the number of intracranial electrode implantations required.

Adult‑onset hypothalamic hamartoma:origin of epilepsy?

Background Hypothalamic hamartoma(HH)is a congenital non-progressive lesion of hypothalamus during fetal development.Mass-like lesions in different anatomical locations often develop a variously disabling course presenting with cognitive decline,psychiatric symptoms,as well as multiple seizure types.As a rare disease,HH is relatively common in infants and children,but it is extremely rare in adults.Case presentation We reported a case of adult-onset hypothalamic hamartoma,and summarized and analyzed relevant reports and studies of HH worldwide.The patient had clinical manifestations characterized by multiple seizure forms.After stereotactic radiofrequency thermocoagulation and drug treatment,the condition was effectively controlled.The patient was followed up till October 2022,with no recurrence of seizures.Conclusions Epilepsy caused by HH can resemble that of temporal lobe seizures,as HH forms a complex epileptogenic network with other regions of the brain through anatomical and functional connections.Early treatment of HH can provide better control of the symptoms of epilepsy,and patients with longer disease courses may have more complications.

Emerging personalized virtual brain models: next-generation resection neurosurgery for drug-resistant epilepsy?

Recently,a novel workflow known as the virtual epileptic patient(VEP)has been proposed by a research team from Aix Marseille Universitéin their papers published in Lancet Neurology,Science Translational Medicine and Epilepsia.This method involves creating an individualized virtual brain model based on computational modelling,which can facilitate clinical decision-making by estimating the epileptogenic zone and performing the virtual surgery.Here,we summarize brief workflow,strengths,and limitations of VEP,as well as its performance in a retrospective study of 53 patients with drug-resistant focal epilepsy who underwent stereoelectroencephalography.A large-scale clinical trial(NCT03643016)is underway to further assess VEP,which is expected to enroll 356 patients prospectively.As supporting evidence accumulates,the clinical application of VEP has the potential to improve clinical practice,leading to better outcomes and qualities of life of patients.

Ganglioglioma surgery associated with postoperative status epilepticus:a case report

Background Gangliogliomas are brain tumors associated with drug-resistant focal epilepsy.In most cases,seizures improve after surgical treatment.It is still not concluded to what extent the lesion itself or the perilesional area contributes to the epileptogenicity.Case presentation In the case presented in this report,the patient,a 24-year-old Caucasian male,developed a refractory status epilepticus after a surgical attempt to remove a cerebral ganglioglioma.The postoperative magnetic resonance imaging revealed that the lesion was intact,and that inadvertently only the perilesional area and adjacent cortex had been resected.The patient underwent a new surgical procedure where the ganglioglioma was removed,and the status epilepticus cessated.Conclusions This clinical case suggests that the lesion itself plays an important role in seizure generation and propagation,and notably,that the surrounding cortex by an inhibitory action can act as a gate to seizure spread.

Advances of Intracranial Electroencephalography in Localizing the Epileptogenic Zone

Intracranial electroencephalography（i EEG）provides the best precision in estimating the location and boundary of an epileptogenic zone. Analysis of i EEG in the routine EEG frequency range（0.5-70 Hz） remains the basis in clinical practice. Low-voltage fast activity is the most commonly reported ictal onset pattern in neocortical epilepsy, and low-frequency high-amplitude repetitive spiking is the most commonly reported ictal onset pattern in mesial temporal lobe epilepsy. Recent studies using wideband EEG recording have demonstrated that examining higher（80-1000 Hz） and lower（0.016-0.5 Hz） EEG frequencies can provide additional diagnostic information and help to improve the surgical outcome. In addition,novel computational techniques of i EEG signal analysis have provided new insights into the epileptic network.Here, we review some of these recent advances. Although these sophisticated and advanced techniques of i EEG analysis show promise in localizing the epileptogenic zone,their utility needs to be further validated in larger studies.

Prognostic value of high-frequency oscillations combined with multimodal imaging methods for epilepsy surgery

Background:The combination of high-frequency oscillations(HFOs)with single-mode imaging methods has been proved useful in identifying epileptogenic zones,whereas few studies have examined HFOs combined with multimodal imaging methods.The aim of this study was to evaluate the prognostic value of ripples,an HFO subtype with a frequency of 80 to 200 Hz is combined with multimodal imaging methods in predicting epilepsy surgery outcome.Methods:HFOs were analyzed in 21 consecutive medically refractory epilepsy patients who underwent epilepsy surgery.All patients underwent positron emission tomography(PET)and deep electrode implantation for stereo-electroencephalography(SEEG);11 patients underwent magnetoencephalography(MEG).Sensitivity,specificity,positive predictive value,negative predictive value,and accuracy in predicting surgical outcome were calculated for ripples combined with PET,MEG,both PET and MEG,and PET combined with MEG.Kaplan-Meier survival analyses were conducted in each group to estimate prognostic value.Results:The study included 13 men and 8 women.Accuracy for ripples,PET,and MEG alone in predicting surgical outcome was 42.9%,42.9%,and 81.8%,respectively.Accuracy for ripples combined with PET and MEG was the highest.Resection of regions identified by ripples,MEG dipoles,and combined PET findings was significantly associated with better surgical outcome(P<0.05).Conclusions:Intracranial electrodes are essential to detect regions which generate ripples and to remove these areas which indicate good surgical outcome for medically intractable epilepsy.With the assistance of presurgical noninvasive imaging examinations,PET and MEG,for example,the SEEG electrodes would identify epileptogenic regions more effectively.