Lesion focused radiofrequency thermocoagulation of bottom-of-sulcus focal cortical dysplasia type IIb: Conceptional considerations with regard to the epileptogenic zone

2018 ◽  
Vol 142 ◽  
pp. 143-148 ◽  
Author(s):  
Jörg Wellmer
Keyword(s):  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Epileptogenic Zone ◽  
Radiofrequency Thermocoagulation

scholarly journals Validating EEG, MEG and combined MEG and EEG beamforming for an estimation of the epileptogenic zone in focal cortical dysplasia

2021 ◽  
Author(s):  
Frank Neugebauer ◽  
Marios Antonakakis ◽  
Kanjana Unnwongse ◽  
Yaroslav Parpaley ◽  
Jörg Wellmer ◽  
...  
Keyword(s):  
Regularization Parameter ◽  
Focal Cortical Dysplasia ◽  
Estimation Method ◽  
Cortical Dysplasia ◽  
Source Analysis ◽  
Seizure Freedom ◽  
Epileptogenic Zone ◽  
Scanning Method ◽  
Eeg Source Analysis ◽  
Skull Conductivity

AbstractMEG and EEG source analysis is frequently used for the presurgical evaluation of pharma-coresistant epilepsy patients. The source localization of the epileptogenic zone depends, among other aspects, on the selected inverse and forward approaches and their respective parameter choices. In this validation study, we compare for the inverse problem the standard dipole scanning method with two beamformer approaches and we investigate the influence of the covariance estimation method and the strength of regularization on the localization performance for EEG, MEG and combined EEG and MEG. For forward modeling, we investigate the difference between calibrated six-compartment and standard three-compartment head modeling. In a retrospective study of two patients with focal epilepsy due to focal cortical dysplasia type IIb and seizure-freedom following lesionectomy or radiofrequency-guided thermocoagulation, we used the distance of the localization of interictal epileptic spikes to the resection cavity resp. rediofrequency lesion as reference for good localization. We found that beamformer localization can be sensitive to the choice of the regularization parameter, which has to be individually optimized. Estimation of the covariance matrix with averaged spike data yielded more robust results across the modalities. MEG was the dominant modality and provided a good localization in one case, while it was EEG for the other. When combining the modalities, the good results of the dominant modality were mostly not spoiled by the weaker modality. For appropriate regularization parameter choices, the beamformer localized better than the standard dipole scan. Compared to the importance of an appropriate regularization, the sensitivity of the localization to the head modeling was smaller, due to similar skull conductivity modeling and the fixed source space without orientation constraint.

scholarly journals Contralateral insular epileptogenic hub causing seizure relapse after opercular focal cortical dysplasia surgery and response to radiofrequency thermocoagulation: illustrative case

2021 ◽  
Vol 2 (5) ◽  
Author(s):  
Pushkaran Jayapaul ◽  
Shameer Aslam ◽  
Bindhu Mangalath Rajamma ◽  
Siby Gopinath ◽  
Ashok Pillai
Keyword(s):  
Focal Cortical Dysplasia ◽  
Positron Emission Tomography Imaging ◽  
Cortical Dysplasia ◽  
Illustrative Case ◽  
Epileptogenic Zone ◽  
Pharmacoresistant Epilepsy ◽  
Novel Technique ◽  
Positron Emission ◽  
Seizure Relapse ◽  
The Right

BACKGROUND The reevaluation and management of seizure relapse following resective surgery in magnetic resonance imaging (MRI)-negative pharmacoresistant epilepsy remains a significant challenge. OBSERVATIONS A 25-year-old right-handed male with medically refractory epilepsy presented with nonlocalizing electroencephalography (EEG) and MRI. Stereo-EEG (SEEG) implantation based on semiology and positron emission tomography imaging revealed a left frontal opercular focus with rapid bilateral insular ictal synchrony. The initial epileptogenic zone was resected and pathologically proven to be type 2A focal cortical dysplasia (FCD). Seizure relapse after 9 months was eventually reinvestigated, and repeat SEEG revealed a secondary epileptogenic focus in the contralateral insula. A novel technique of volumetric stereotactic radiofrequency ablation (vRFA) was utilized for the right insular focus, following which, the patient remains seizure-free for 20 months. He suffered a transient bilateral opercular syndrome following the second intervention that eventually resolved. LESSONS The authors present clinical evidence to suggest epileptogenic nodes distant from the primary focus as a mechanism for seizure relapse following FCD surgery and the importance of bilateral insular SEEG coverage. The authors also describe a novel technique of minimally invasive vRFA that allows ablation of a larger volume of cerebral cortex when compared to conventional bedside SEEG electrode thermocoagulation.

scholarly journals On The Use of Machine Learning Algorithms to Classify Focal Cortical Dysplasia on MRI

2021 ◽  
Author(s):  
João Guilherme Pereira ◽  
Matheus de Freitas Oliveira Baffa ◽  
Fabrício Henrique Simozo ◽  
Luiz Otavio Murta Junior ◽  
Joaquim Cezar Felipe
Keyword(s):  
Deep Neural Network ◽  
Surgical Intervention ◽  
Refractory Epilepsy ◽  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Machine Learning Algorithms ◽  
Textural Features ◽  
Epileptogenic Zone ◽  
Neural Network Classifier ◽  
Multiple Classifiers

Refractory epilepsy is a condition characterized by epileptic seizure occurrence which cannot be controlled with antiepileptic drugs. This condition is associated with an excessive neuronal discharge produced by a group of neurons in a certain epileptogenic zone. Focal Cortical Dysplasia (FCD), usually found in these zones, was detected as one of the main causes of refractory epilepsy. In these cases, surgical intervention is necessary to minimize or eliminate the seizure occurrences. However, surgical treatment is only indicated in cases where there is complete certainty of the FCD. In order to assist neurosurgeons to detect precisely these regions, this paper aims to develop a classification method to detect FCD on MRI based on morphological and textural features from a voxel-level perspective. Multiple classifiers were tested throughout the extracted features, the best results achieved an accuracy of 91.76% using a Deep Neural Network classifier and 96.15% with J48 Decision Tree. The set of evaluating metrics showed that the results are promising.

Can Magnetoencephalography Identify the Epileptogenic Pathology in Children?

2020 ◽  
pp. 182-190
Author(s):  
Won Seok Chang ◽  
Hiroshi Otsubo
Keyword(s):  
Magnetic Resonance Imaging ◽  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Emission Tomography ◽  
Metabolic Imaging ◽  
Epileptogenic Zone ◽  
Structural Imaging ◽  
Medical Treatments ◽  
Positron Emission ◽  
Other Information

Because epilepsy in children can result in cognitive decline and psychomotor disabilities in later periods of life, controlling the seizures early and aggressively is recommended. Approximately 30 to 35% of children with epilepsy continue to have seizures despite optimized medical treatments. For these children, epilepsy surgery to resect the focal epileptogenic zone is the best remaining option. Presurgical evaluation, including video electroencephalography and magnetoencephalography (MEG) for physiological information, magnetic resonance imaging for structural imaging, positron emission tomography for metabolic imaging, and neuropsychological examinations are essential for assessment of the laterality and focality of the epileptogenic zone. In this chapter, specific characteristics of MEG findings are correlated with the histopathology of epilepsy (i.e., focal cortical dysplasia, oligodendrogliosis consisting of increase in oligodendroglia-like cells in the subcortical areas, and filaminopathy with astrocytic inclusions). In addition to MEG findings, the integration of other information is used to inform the surgical strategy for children with pharmaco-resistant epilepsy.

Surgical strategy for focal cortical dysplasia based on the analysis of the spike onset and peak zones on magnetoencephalography

2020 ◽  
Vol 133 (6) ◽  
pp. 1850-1862 ◽  
Author(s):  
Hiroshi Shirozu ◽  
Akira Hashizume ◽  
Hiroshi Masuda ◽  
Akiyoshi Kakita ◽  
Hiroshi Otsubo ◽  
...  
Keyword(s):  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Complete Resection ◽  
Surgical Strategy ◽  
Class I ◽  
Type I ◽  
Incomplete Resection ◽  
Epileptogenic Zone ◽  
Current Dipole ◽  
Significant Difference

OBJECTIVEThe aim of this study was to elucidate the surgical strategy for focal cortical dysplasia (FCD) based on the interictal analysis on magnetoencephalography (MEG). For this purpose, the correlation between the spike onset zone (Sp-OZ) and the spike peak zone (Sp-PZ) on MEG was evaluated to clarify the differences in the Sp-OZ and its correlation with Sp-PZ in FCD subtypes to develop an appropriate surgical strategy.METHODSForty-one FCD patients (n = 17 type I, n = 13 type IIa, and n = 11 type IIb) were included. The Sp-OZ was identified by the summation of gradient magnetic-field topography (GMFT) magnitudes at interictal MEG spike onset, and Sp-PZ was defined as the distribution of the equivalent current dipole (ECD) at spike peak. Correlations between Sp-OZ and Sp-PZ distributions were evaluated and compared with clinical factors and seizure outcomes retrospectively.RESULTSGood seizure outcomes (Engel class I) were obtained significantly more often in patients with FCD type IIb (10/11, 90.9%) than those with type IIa (4/13, 30.8%; p = 0.003) and type I (6/17, 35.3%; p = 0.004). The Sp-OZ was significantly smaller (1 or 2 gyri) in type IIb (10, 90.9%) than in type IIa (4, 30.8%; p = 0.003) or type I (9, 53.0%; p = 0.036). Concordant correlations between the Sp-OZ and Sp-PZ were significantly more frequent in type IIb (7, 63.6%) than in type IIa (1, 7.7%; p = 0.015) or type I (1, 5.8%; p = 0.004). Complete resection of the Sp-OZ achieved significantly better seizure outcomes (Engel class I: 9/10, 90%) than incomplete resection (11/31, 35.5%) (p = 0.003). In contrast, complete resection of the Sp-PZ showed no significant difference in good seizure outcomes (9/13, 69.2%) compared with incomplete resection (11/28, 39.3%).CONCLUSIONSThe Sp-OZ detected by MEG using GMFT and its correlation with Sp-PZ were related to FCD subtypes. A discordant distribution between Sp-OZ and Sp-PZ in type I and IIa FCD indicated an extensive epileptogenic zone and a complex epileptic network. Type IIb showed a restricted epileptogenic zone with the smaller Sp-OZ and concordance between Sp-OZ and Sp-PZ. Complete resection of the Sp-OZ provided significantly better seizure outcomes than incomplete resection. Complete resection of the Sp-PZ was not related to seizure outcomes. There was a definite difference in the epileptogenic zone among FCD subtypes; hence, an individual surgical strategy taking into account the correlation between the Sp-OZ and Sp-PZ should be considered.

Surgery for Nontumoral Insular Epilepsy Explored by Stereoelectroencephalography

Neurosurgery ◽  
2016 ◽  
Vol 79 (4) ◽  
pp. 578-588 ◽  
Author(s):  
Guillaume Gras-Combe ◽  
Lorella Minotti ◽  
Dominique Hoffmann ◽  
Alexandre Krainik ◽  
Philippe Kahane ◽  
...  
Keyword(s):  
Focal Cortical Dysplasia ◽  
Intractable Epilepsy ◽  
Insular Cortex ◽  
Cavernous Angioma ◽  
Cortical Dysplasia ◽  
Electrode Placement ◽  
Seizure Freedom ◽  
Epileptogenic Zone ◽  
Pharmacoresistant Epilepsy ◽  
The Right

Abstract BACKGROUND Hidden by the perisylvian operculi, insular cortex has long been underexplored in the context of epilepsy surgery. Recent studies advocated stereoelectroencephalography (SEEG) as a reliable tool to explore insular cortex and its involvement in intractable epilepsy and suggested that insular seizures could be an underestimated entity. However, the results of insular resection to treat pharmacoresistant epilepsy are rarely reported. OBJECTIVE We report 6 consecutive cases of right insular resection performed based on anatomoelectroclinical correlations provided by SEEG. METHODS Six right-handed patients (3 male, 3 female) with drug-resistant epilepsy underwent comprehensive presurgical evaluation. Based on video electroencephalographic recordings, they all underwent SEEG evaluation with bilateral (n = 4) or unilateral right (n = 2) insular depth electrode placement. All patients had both orthogonal and oblique (1 anterior, 1 posterior) insular electrodes (n = 4-6 electrodes). Preoperative magnetic resonance imaging findings were normal in 4 patients, 1 patient had right insular focal cortical dysplasia, and 1 patient had a right opercular postoperative scar (cavernous angioma). All patients underwent right partial insular corticectomy via the subpial transopercular approach. RESULTS Intracerebral recordings demonstrated an epileptogenic zone confined to the right insula in all patients. After selective insular resection, 5 of 6 patients were seizure free (Engel class I) with a mean follow-up of 36.2 months (range, 18-68 months). Histological findings revealed focal cortical dysplasia in 5 patients and a gliosis scar in 1 patient. All patients had minor transient neurological deficit (eg, facial paresis, dysarthria). CONCLUSION Insular resection based on SEEG findings can be performed safely with a significant chance of seizure freedom.

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