Childhood temporal lobe epilepsy: correlation between electroencephalography and magnetic resonance spectroscopy: a case-control study

Correlation of magnetic resonance spectroscopy and magnetic resonance imaging with findings of electroencephalography in patients with temporal lobe epilepsy

INTRODUCTION

This research aimed to see how well magnetic resonance spectroscopy (MRS) could identify the lateralization side in individuals with temporal lobe epilepsy (TLE) compared to electroencephalography (EEG) and magnetic resonance imaging (MRI) results.

METHODS

Twenty-three individuals were included in this research and diagnosed with TLE (both clinically and by EEG). Clinical exams, interictal EEG, and MRI were performed on all patients. In addition, the individuals were also subjected to proton MRS.

RESULTS

The age range of 23 participants was 20-55 years (mean = 34.6 ± 8.5); 10 were male (44%), and 13 were female (56%). The right temporal lobe MRI showed a sensitivity and specificity of 60% and 55% for detecting mesial temporal lobe sclerosis (MTS) foci, respectively (positive predictive value (PPV) of 27% and negative predictive value (NPV) of 83%). MRI showed 83% sensitivity and 35% specificity for MTS foci in the left temporal lobe (PPV of 31% and NPV of 86%). MRS showed 61% sensitivity and 100% specificity in the right temporal lobe (PPV 100%) and 80% sensitivity and specificity in the left temporal lobe (PPV 100%) for identifying MTS foci. Overall, MRS (both left and right) results matched EEG findings.

CONCLUSION

MRS is a potential noninvasive neuroradiology technique for assessing epilepsy patients because it is more sensitive than structural MRI in identifying MTS. The results of the study overall appears to be of interest but still need further support from future studies with larger sample sizes.

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.

Diagnostic and prognostic role of proton single-voxel spectroscopy (SVS) in non-lesional epilepsy pediatric patients: prospective controlled study

Background

We aimed to verify the diagnostic and prognostic role of proton single-voxel spectroscopy (SVS) in children with non-lesional epilepsy and its add-on value to conventional MR. The prospective controlled study carried out on the epileptic patients who were regularly following in the pediatric neurology clinic in our university hospital, over the period from July 2017 to July 2018. It compared SVS findings (NAA/Cr, NAA/Cho, and NAA/Cho+Cr ratios) between the case (50 patients) and control group (20 children), between the cases with different seizures semiology and between the patients with intractable and non-intractable epilepsy.

Results

NAA/Cr ratio showed a significant difference between the patients with intractable and non-intractable epilepsy in the basal ganglia (P value 0.005) and white matter (P value 0.043) with cutoff values of 1.5 and 1.9 respectively. A significant difference of NAA/Cho ratio was found between generalized seizures cases and other seizures semiology in basal ganglia (P value 0.012) and cortex (P value <.001). There was no significant difference between the patient and control groups or between generalized seizures cases and the control group.

Conclusion

Proton SVS has limited diagnostic value in non-lesional epilepsy pediatric patients, in differentiation between generalized seizures and other seizure types, but, it has a good prognostic role in predicting patients who will develop intractable epilepsy.

NMR-based metabolomics in pediatric drug resistant epilepsy - preliminary results

Epilepsy in children is the most frequent, heterogeneous and difficult to classify chronic neurologic condition with the etiology found in 35–40% of patients. Our aim is to detect the metabolic differences between the epileptic children and the children with no neurological abnormalities in order to define the metabolic background for therapy monitoring. The studied group included 28 epilepsy patients (median age 12 months) examined with a diagnostic protocol including EEG, videoEEG, 24-hour-EEG, tests for inborn errors of metabolism, chromosomal analysis and molecular study. The reference group consisted of 20 patients (median age 20 months) with no neurological symptoms, no development delay nor chronic diseases. ¹H-NMR serum spectra were acquired on 400 MHz spectrometer and analyzed using multivariate and univariate approach with the application of correction for age variation. The epilepsy group was characterized by increased levels of serum N-acetyl-glycoproteins, lactate, creatine, glycine and lipids, whereas the levels of citrate were decreased as compared to the reference group. Choline, lactate, formate and dimethylsulfone were significantly correlated with age. NMR-based metabolomics could provide information on the dynamic metabolic processes in drug-resistant epilepsy yielding not only disease-specific biomarkers but also profound insights into the disease course, treatment effects or drug toxicity.

Proton MR Spectroscopy in Patients with Nonlesional Insular Cortex Epilepsy Confirmed by Invasive EEG Recordings

BACKGROUND AND PURPOSE

Recent studies suggest that a nonnegligible proportion of drug-resistant epilepsy surgery candidates have an epileptogenic zone that involves the insula. We aimed to examine the value of proton magnetic resonance spectroscopy (¹ H-MRS) in identifying patients with insular cortex epilepsy.

METHODS

Patients with possible nonlesional drug-refractory insular epilepsy underwent a voxel-based ¹ H-MRS study prior to an intracranial electroencephalographic (EEG) study. Patients were then divided into two groups based on invasive EEG findings: the insular group with evidence of insular seizures and the noninsular group with no evidence of insular seizures. Sixteen age-matched healthy controls were also scanned for normative data.

RESULTS

Twenty-two epileptic patients were recruited, 12 with insular seizures and 10 with extra-insular seizures. Ipsilateral and contralateral insular N-acetyl-aspartate concentrations ([NAA]) and NAA/Cr ratios were found to be similar in both patient groups. No significant differences in [NAA] or NAA/Cr ratios were found between the insular group, noninsular group, and healthy controls. [NAA] and NAA/Cr asymmetry indices correctly lateralized the seizure focus in only 16.7% and 0% of patients, respectively.

CONCLUSIONS

Our preliminary findings suggest that ¹ H-MRS fares poorly in identifying patients with nonlesional insular epilepsy.