scholarly journals Epileptogenic zone localization using intraoperative gamma oscillation regularity analysis in epilepsy surgery for cavernomas: patient series

2021 ◽  
Vol 1 (4) ◽  
Author(s):  
Yosuke Sato ◽  
Yoshihito Tsuji ◽  
Yuta Kawauchi ◽  
Kazuki Iizuka ◽  
Yusuke Kobayashi ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Focal Epilepsy ◽  
Sample Entropy ◽  
Gamma Oscillation ◽  
Epileptogenic Zone ◽  
Hemosiderin Deposition ◽  
Patient Series

BACKGROUNDIn epilepsy surgery for cavernoma with intractable focal epilepsy, removal of the cavernoma with its surrounding hemosiderin deposition and other extended epileptogenic zone has been shown to improve postsurgical seizures. However, there has been no significant association between such an epileptogenic zone and intraoperative electrocorticography (ECoG) findings. The authors recently demonstrated that high regular gamma oscillation (30–70 Hz) regularity (GOR) significantly correlates with epileptogenicity.OBSERVATIONSThe authors evaluated the utility of intraoperative GOR analysis in epilepsy surgery for cavernomas. The authors also analyzed intraoperative ECoG data from 6 patients with cavernomas. The GOR was calculated using a sample entropy algorithm. In 4 patients, the GOR was significantly high in the area with the pathological hemosiderin deposition. In 2 patients with temporal cavernoma, the GOR was significantly high in both the hippocampus and the area with the pathological hemosiderin deposition. ECoG showed no obvious epileptic waveforms in 3 patients, whereas extensive spikes were observed in 3 patients. All patients underwent cavernoma removal plus resection of the area with significantly high GOR. The 2 patients with temporal cavernomas underwent additional hippocampal transection. All patients were seizure free after surgery.LESSONSThe high GOR may be a novel intraoperative marker of the epileptogenic zone in epilepsy surgery for cavernomas.

Epilepsy surgery

2019 ◽  
pp. practneurol-2019-002192 ◽  
Author(s):  
Fergus Rugg-Gunn ◽  
Anna Miserocchi ◽  
Andrew McEvoy
Keyword(s):  
Epilepsy Surgery ◽  
Focal Epilepsy ◽  
Seizure Freedom ◽  
Epileptogenic Zone ◽  
Nuclear Medicine Imaging ◽  
Co Morbidity ◽  
Surgical Evaluation ◽  
Clonic Seizures ◽  
Eeg Recordings ◽  
Electroencephalogram Eeg

Epilepsy surgery offers the chance of seizure remission for the 30%–40% of patients with focal epilepsy whose seizures continue despite anti-epileptic medications. Epilepsy surgery encompasses curative resective procedures, palliative techniques such as corpus callosotomy and implantation of stimulation devices. Pre-surgical evaluation aims to identify the epileptogenic zone and to prevent post-operative neurological and cognitive deficits. This entails optimal imaging, prolonged video-electroencephalogram (EEG) recordings, and neuropsychological and psychiatric assessments; some patients may then require nuclear medicine imaging and intracranial EEG recording. The best outcomes are in those with an electro-clinically concordant structural lesion on MRI (60%–70% seizure freedom). Lower rates of seizure freedom are expected in people with extra-temporal lobe foci, focal-to-bilateral tonic-clonic seizures, normal structural imaging, psychiatric co-morbidity and learning disability. Nevertheless, surgery for epilepsy is under-used and should be considered for all patients with refractory focal epilepsy in whom two or three anti-epileptic medications have been ineffective.

scholarly journals Multimodal localization and surgery for epileptic spasms of focal origin: a review

2018 ◽  
Vol 45 (3) ◽  
pp. E4 ◽  
Author(s):  
Taylor J. Abel ◽  
Emma Losito ◽  
George M. Ibrahim ◽  
Eishi Asano ◽  
James T. Rutka
Keyword(s):  
Epilepsy Surgery ◽  
Focal Epilepsy ◽  
Intractable Epilepsy ◽  
Epileptogenic Zone ◽  
Invasive Monitoring ◽  
Current State ◽  
Epileptic Spasms ◽  
Clinical Series ◽  
Postoperative Seizure ◽  
Monitoring Technologies

Epileptic spasms (ES) are a common manifestation of intractable epilepsy in early life and can lead to devastating neurodevelopmental consequences. Epilepsy surgery for ES is challenging because of inherent difficulties in localizing the epileptogenic zone in affected infants and children. However, recent clinical series of resective neurosurgery for ES suggest that not only is surgery a viable option for appropriately selected patients, but postoperative seizure outcomes can be similar to those achieved in other types of focal epilepsy. Increased awareness of ES as a potentially focal epilepsy, along with advances in neuroimaging and invasive monitoring technologies, have led to the ability to surgically treat many patients with ES who were previously not considered surgical candidates. In this study, the authors review the current state of epilepsy surgery for ES. Specifically, they address how advances in neuroimaging and invasive monitoring have facilitated patient selection, presurgical evaluation, and ultimately, resection planning.

scholarly journals Clinical evaluation of neuroinflammation in child-onset focal epilepsy: a translocator protein PET study

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Kuriko Kagitani-Shimono ◽  
Hiroki Kato ◽  
Ryoko Kuwayama ◽  
Koji Tominaga ◽  
Shin Nabatame ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Focal Epilepsy ◽  
Focal Cortical Dysplasia ◽  
Neurological Diseases ◽  
Hippocampal Sclerosis ◽  
Standardized Uptake Value ◽  
Translocator Protein ◽  
Diagnostic Tools ◽  
Epileptogenic Zone ◽  
Positron Emission

Abstract Background Neuroinflammation is associated with various chronic neurological diseases, including epilepsy; however, neuroimaging approaches for visualizing neuroinflammation have not been used in the clinical routine yet. In this study, we used the translocator protein positron emission tomography (PET) with [11C] DPA713 to investigate neuroinflammation in the epileptogenic zone in patients with child-onset focal epilepsy. Methods Patients with intractable focal epilepsy were recruited at the Epilepsy Center of Osaka University; those who were taking any immunosuppressants or steroids were excluded. PET images were acquired for 60 min after intravenous administration of [11C] DPA713. The PET image of [11C] DPA713 was co-registered to individual’s magnetic resonance imaging (MRI), and the standardized uptake value ratio (SUVr) in regions of interest, which were created in non-lesions and lesions, was calculated using the cerebellum as a pseudo-reference region. In the case of epilepsy surgery, the correlation between SUVr in lesions and pathological findings was analyzed. Results Twenty-seven patients (mean age: 11.3 ± 6.2 years, male/female: 17/10) were included in this study. Of these, 85.1% showed increased uptake of [11C] DPA713 in the focal epileptic lesion. Three patients showed epileptic spasms, suggesting partial seizure onset, and all 18 patients with abnormal lesions on MRI were similarly highlighted by significant uptake of [11C] DPA713. DPA713-positive patients had a broad range of etiologies, including focal cortical dysplasia, tumors, infarction, and hippocampal sclerosis. Five out of nine MRI-negative patients showed abnormal [11C] DPA713 uptake. The SUVr of [11C] DPA713 in lesions was significantly higher than that in non-lesions. In seven patients who underwent epilepsy surgery, increased [11C] DPA713 uptake was associated with microglial activation. Conclusions This study indicates that [11C] DPA713 uptake has valuable sensitivity in the identification of epileptic foci in child-onset focal epilepsy, and inflammation is implicated in the pathophysiology in the epileptic foci caused by various etiologies. Further research is required to establish diagnostic tools for identifying focal epileptogenic zones.

Lost in Transition: The Long and Winding Road Toward Epilepsy Surgery—An Analysis of Obstacles Prior to Surgery and Call for Orchestrated Health Care Efforts in Epilepsy

2020 ◽  
Vol 18 (06) ◽  
pp. 286-291
Author(s):  
Wolfgang Graf ◽  
Burkhard S. Kasper ◽  
Sunjay Sharma ◽  
Ekkehard M. Kasper
Keyword(s):  
Epilepsy Surgery ◽  
Focal Epilepsy ◽  
Average Duration ◽  
Seizure Freedom ◽  
Epileptogenic Zone ◽  
Careful Patient ◽  
Successful Approach ◽  
Structural Lesion ◽  
The Moment ◽  
Cerebral Convolutions

AbstractDifficult-to-treat epilepsy is defined as ongoing seizures despite adequate pharmacological treatment. This condition is affecting a significant percentage of epilepsy patients and is estimated to be as high as one-third of all patients. Epilepsy surgery, targeting the removal of the key parts of cerebral convolutions responsible for seizure generation and often including a structural lesion, can be a very successful approach. However, this necessitates careful patient selection by comprehensive investigations, proving the localization of the epileptogenic zone as well as measures to make such surgeries safe. With careful selection as a prerequisite, the percentage of patients achieving seizure freedom by neurosurgical intervention is high, approximating two-thirds of all epilepsy surgeries performed. In contrast, the average duration of a patient's pharmacoresistant focal epilepsy prior to surgery anywhere around the globe is around 20 years. Given that typical patients are ∼30 to 40 years of age at the time of surgery, many patients have been living with chronic seizures since childhood or adolescence. This means that most of these patients have been going through several stages of medical care for years or even decades, both as children and adults, without ever being fully investigated and/or selected for surgery which is concerning. Yet, there is no set standard for a timeline leading toward successful surgery in epilepsy. It is obvious that the average transit period from the moment of first seizure manifestation until the day of successful surgery takes much too long. This is the reason why we see these patients lost in transition.

scholarly journals Utility of magnetic source imaging in nonlesional focal epilepsy: a prospective study

2020 ◽  
Vol 48 (4) ◽  
pp. E16
Author(s):  
Ismail Sidky Mohamed ◽  
Dènahin Hinnoutondji Toffa ◽  
Manon Robert ◽  
Patrick Cossette ◽  
Arline-Aude Bérubé ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Surgical Outcome ◽  
Focal Epilepsy ◽  
Added Value ◽  
Epileptogenic Zone ◽  
Presurgical Evaluation ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Magnetic Source ◽  
Blinded Study

OBJECTIVEFor patients with nonlesional refractory focal epilepsy (NLRFE), localization of the epileptogenic zone may be more arduous than for other types of epilepsy and frequently requires information from multiple noninvasive presurgical modalities and intracranial EEG (icEEG). In this prospective, blinded study, the authors assessed the clinical added value of magnetic source imaging (MSI) in the presurgical evaluation of patients with NLRFE.METHODSThis study prospectively included 57 consecutive patients with NLRFE who were considered for epilepsy surgery. All patients underwent noninvasive presurgical evaluation and then MSI. To determine the surgical plan, discussion of the results of the presurgical evaluation was first undertaken while discussion participants were blinded to the MSI results. MSI results were then presented. MSI influence on the initial management plan was assessed.RESULTSMSI results influenced patient management in 32 patients. MSI results led to the following changes in surgical strategy in 14 patients (25%): allowing direct surgery in 6 patients through facilitating the detection of subtle cortical dysplasia in 4 patients and providing additional concordant diagnostic information to other presurgical workup in another 2 patients; rejection of surgery in 3 patients originally deemed surgical candidates; change of plan from direct surgery to icEEG in 2 patients; and allowing icEEG in 3 patients deemed not surgical candidates. MSI results led to changed electrode locations and contact numbers in another 18 patients. Epilepsy surgery was performed in 26 patients influenced by MSI results and good surgical outcome was achieved in 21 patients.CONCLUSIONSThis prospective, blinded study showed that information provided by MSI allows more informed icEEG planning and surgical outcome in a significant percentage of patients with NLRFE and should be included in the presurgical workup in those patients.

scholarly journals Synaptic Reshaping and Neuronal Outcomes in the Temporal Lobe Epilepsy

2021 ◽  
Vol 22 (8) ◽  
pp. 3860
Author(s):  
Elisa Ren ◽  
Giulia Curia
Keyword(s):  
Animal Models ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Current Knowledge ◽  
Focal Epilepsy ◽  
Ex Vivo ◽  
Hippocampal Sclerosis ◽  
Control Group ◽  
Epileptogenic Zone ◽  
Epileptiform Discharges

Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, characterized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.

scholarly journals Efficient automated localization of ECoG electrodes in CT images via shape analysis

2021 ◽  
Vol 16 (4) ◽  
pp. 543-554
Author(s):  
Jessica Centracchio ◽  
Antonio Sarno ◽  
Daniele Esposito ◽  
Emilio Andreozzi ◽  
Luigi Pavone ◽  
...  
Keyword(s):  
Shape Analysis ◽  
Focal Epilepsy ◽  
Support Vector ◽  
Epileptogenic Zone ◽  
Platinum Electrodes ◽  
Public Repository ◽  
Automated Method ◽  
Depth Electrodes ◽  
Ethical Approval ◽  
Cortical Regions

Abstract Purpose People with drug-refractory epilepsy are potential candidates for surgery. In many cases, epileptogenic zone localization requires intracranial investigations, e.g., via ElectroCorticoGraphy (ECoG), which uses subdural electrodes to map eloquent areas of large cortical regions. Precise electrodes localization on cortical surface is mandatory to delineate the seizure onset zone. Simple thresholding operations performed on patients’ computed tomography (CT) volumes recognize electrodes but also other metal objects (e.g., wires, stitches), which need to be manually removed. A new automated method based on shape analysis is proposed, which provides substantially improved performances in ECoG electrodes recognition. Methods The proposed method was retrospectively tested on 24 CT volumes of subjects with drug-refractory focal epilepsy, presenting a large number (> 1700) of round platinum electrodes. After CT volume thresholding, six geometric features of voxel clusters (volume, symmetry axes lengths, circularity and cylinder similarity) were used to recognize the actual electrodes among all metal objects via a Gaussian support vector machine (G-SVM). The proposed method was further tested on seven CT volumes from a public repository. Simultaneous recognition of depth and ECoG electrodes was also investigated on three additional CT volumes, containing penetrating depth electrodes. Results The G-SVM provided a 99.74% mean classification accuracy across all 24 single-patient datasets, as well as on the combined dataset. High accuracies were obtained also on the CT volumes from public repository (98.27% across all patients, 99.68% on combined dataset). An overall accuracy of 99.34% was achieved for the recognition of depth and ECoG electrodes. Conclusions The proposed method accomplishes automated ECoG electrodes localization with unprecedented accuracy and can be easily implemented into existing software for preoperative analysis process. The preliminary yet surprisingly good results achieved for the simultaneous depth and ECoG electrodes recognition are encouraging. Ethical approval n°NCT04479410 by “IRCCS Neuromed” (Pozzilli, Italy), 30th July 2020.

EEG Source Imaging (ESI) utility in clinical practice

2020 ◽  
Vol 65 (6) ◽  
pp. 673-682
Author(s):  
Pegah Khosropanah ◽  
Eric Tatt-Wei Ho ◽  
Kheng-Seang Lim ◽  
Si-Lei Fong ◽  
Minh-An Thuy Le ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Cost Effective ◽  
Head Model ◽  
Computational Technique ◽  
Epileptogenic Zone ◽  
Clinical Tool ◽  
Source Imaging ◽  
Localization Accuracy ◽  
Eeg Source Imaging ◽  
Surgical Evaluation

AbstractEpilepsy surgery is an important treatment modality for medically refractory focal epilepsy. The outcome of surgery usually depends on the localization accuracy of the epileptogenic zone (EZ) during pre-surgical evaluation. Good localization can be achieved with various electrophysiological and neuroimaging approaches. However, each approach has its own merits and limitations. Electroencephalography (EEG) Source Imaging (ESI) is an emerging model-based computational technique to localize cortical sources of electrical activity within the brain volume, three-dimensionally. ESI based pre-surgical evaluation gives an overall clinical yield of 73–91%, depending on choice of head model, inverse solution and EEG electrode density. It is a cost effective, non-invasive method which provides valuable additional information in presurgical evaluation due to its high localizing value specifically in MRI-negative cases, extra or basal temporal lobe epilepsy, multifocal lesions such as tuberous sclerosis or cases with multiple hypotheses. Unfortunately, less than 1% of surgical centers in developing countries use this method as a part of pre-surgical evaluation. This review promotes ESI as a useful clinical tool especially for patients with lesion-negative MRI to determine EZ cost-effectively with high accuracy under the optimized conditions.

Multimodal approach in the pre-surgical evaluation of focal epilepsy surgery candidates: how far are we from a non-invasive ESI-based “sourcectomy”?

2021 ◽  
Vol 23 (4) ◽  
pp. 661-666
Author(s):  
Giulia Nobile ◽  
Alessandro Consales ◽  
Domenico Tortora ◽  
Mattia Pacetti ◽  
Francesca Gianno ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Focal Epilepsy ◽  
Multimodal Approach ◽  
Non Invasive ◽  
Surgical Evaluation
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