Update on neuroimaging in epilepsy

Differentiation of Epileptic Brain Abnormalities among Neurological Patients at Taif Region Using MRI

This study was conducted to assess the prevalence of epilepsy among different age groups and gender of neurological patients in the Taif region and define the most common brain lesion, affecting epileptic patients living in the Taif city using MRI. Data from 150 patients who were clinically diagnosed with epilepsy and had brain MRIs were analyzed using SPSS. Statistical significance was considered when the p value is 0.05. The percentage of epilepsy was generally higher in males than in females in the Taif city, and seizures were different between the studied age groups. However, epilepsy was more pronounced in females than in males at certain age groups. Moreover, white matter lesions were most commonly found in the studied group (27.7%), followed by focal lesions, edema, and stroke with equal percentages (16.9%) and less commonly with congenital diseases (12%) and atrophic changes (9.6%). Epilepsy was more pronounced in females than in males at certain age groups. White matter lesions were identified as the most common lesion, presenting in epilepsy patients in the Taif city.

Neuroproteomics in Epilepsy: What Do We Know so Far?

Epilepsies are chronic neurological diseases that affect approximately 2% of the world population. In addition to being one of the most frequent neurological disorders, treatment for patients with epilepsy remains a challenge, because a proportion of patients do not respond to the antiseizure medications that are currently available. This results in a severe economic and social burden for patients, families, and the healthcare system. A characteristic common to all forms of epilepsy is the occurrence of epileptic seizures that are caused by abnormal neuronal discharges, leading to a clinical manifestation that is dependent on the affected brain region. It is generally accepted that an imbalance between neuronal excitation and inhibition generates the synchronic electrical activity leading to seizures. However, it is still unclear how a normal neural circuit becomes susceptible to the generation of seizures or how epileptogenesis is induced. Herein, we review the results of recent proteomic studies applied to investigate the underlying mechanisms leading to epilepsies and how these findings may impact research and treatment for these disorders.

Blood DNA methylation pattern is altered in mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy (MTLE) is a common epileptic disorder; little is known whether it is associated with peripheral epigenetic changes. Here we compared blood whole genomic DNA methylation pattern in MTLE patients (n = 30) relative to controls (n = 30) with the Human Methylation 450 K BeadChip assay, and explored genes and pathways that were differentially methylated using bioinformatics profiling. The MTLE and control groups showed significantly different (P < 1.03e-07) DNA methylation at 216 sites, with 164 sites involved hyper- and 52 sites hypo- methylation. Two hyper- and 32 hypo-methylated sites were associated with promoters, while 87 hyper- and 43 hypo-methylated sites corresponded to coding regions. The differentially methylated genes were largely related to pathways predicted to participate in anion binding, oxidoreductant activity, growth regulation, skeletal development and drug metabolism, with the most distinct ones included SLC34A2, CLCN6, CLCA4, CYP3A43, CYP3A4 and CYP2C9. Among the MTLE patients, panels of genes also appeared to be differentially methylated relative to disease duration, resistance to anti-epileptics and MRI alterations of hippocampal sclerosis. The peripheral epigenetic changes observed in MTLE could be involved in certain disease-related modulations and warrant further translational investigations.

Do neuroimaging results impact prognosis of epilepsy surgery? A meta-analysis

The neuroimaging results of drug-resistant epilepsy patients play an important role in the surgery decision and prognosis. The aim of this study was to evaluate the impact of these results on the efficacy of epilepay surgery, and then to explore surgical benefit for epilepsy patients with negative magnetic resonance (MR) images. Twenty-four subgroups describing the outcomes of 1475 epilepsy patients with positive-neuroimaging results and 696 patients with negative-neuroimaging results were involved in the meta-analysis. Overall, the odds of postoperational seizure-free rate were 2.03 times higher in magnetic resonance imaging-positive (MRI-positive) patients than in MRI-negative patients [odds ratio (OR)=2.03, 95% CI (1.67, 2.47), P<0.00001]. For patients with temporal lobe epilepsy (TLE), the odds were 1.76 times higher in those with MRI-positive results than in those with MRI-negative results [OR=1.76, 95% CI (1.34, 2.32), P<0.0001]. For patients with extra-temporal lobe epilepsy (extra-TLE), the odds were 2.88 times higher in MRI-positive patients than in MRI-negative patients [OR=2.88, 95% CI (1.53, 5.43), P=0.001]. It was concluded that the seizure-free rate of MRI-positive patients after surgery was higher than that of MRI-negative patients. For patients with negative results, an appropriate surgery should be concerned for TLE.

PET of serotonin 1A receptors and cerebral glucose metabolism for temporal lobectomy

The objective of this study was to compare 5-hydroxytryptamine receptor 1A (5-HT(1A)) PET with cerebral metabolic rate of glucose (CMRglc) PET for temporal lobectomy planning.

METHODS

We estimated 5-HT(1A) receptor binding preoperatively with (18)F-trans-4-fluoro-N-2-[4-(2-methoxyphenyl) piperazin-1-yl]ethyl-N-(2-pyridyl) cyclohexane carboxamide ((18)F-FCWAY) PET and CMRglc measurement with (18)F-FDG in regions drawn on coregistered MRI after partial-volume correction in 41 patients who had anterior temporal lobectomy with at least a 1-y follow-up. Surgery was tailored to individual preresection evaluations and intraoperative electrocorticography. Mean regional asymmetry values and the number of regions with asymmetry exceeding 2 SDs in 16 healthy volunteers were compared between seizure-free and non-seizure-free patients. (18)F-FCWAY but not (18)F-FDG and MRI data were masked for surgical decisions and outcome assessment.

RESULTS

Twenty-six of 41 (63%) patients seizure-free since surgery had significantly different mesial temporal asymmetries, compared with 15 non-seizure-free patients for both (18)F-FCWAY (F(1,39) = 5.87; P = 0.02) and (18)F-FDG PET (F(1,38) = 5.79; P = 0.021). The probability of being seizure-free was explained by both (18)F-FDG and (18)F-FCWAY PET, but not MRI, with a significant additional (18)F-FCWAY effect (chi(2)(2) = 9.8796; P = 0.0072) after the probability of being seizure-free was explained by (18)F-FDG. Although MRI alone was not predictive, any combination of 2 lateralizing imaging studies was highly predictive of seizure freedom.

CONCLUSION

Our study provides class III evidence that both 5-HT(1A) receptor PET and CMRglc PET can contribute to temporal lobectomy planning. Additional studies should explore the potential for temporal lobectomy based on interictal electroencephalography and minimally invasive imaging studies.