Identifying the epileptogenic zone by four non-invasive imaging techniques versus stereo-EEG in MRI-negative pre-surgery epilepsy patients

Sebastiano, Davide Rossi; Tassi, Laura; Duran, Dunja; Visani, Elisa; Gozzo, Francesca; Cardinale, Francesco; Nobili, Lino; Sole, Angelo Del; Rubino, Annalisa; Dotta, Sara; Schiaffi, Elena; Garbelli, Rita; Franceschetti, Silvana; Spreafico, Roberto; Panzica, Ferruccio

doi:10.1016/j.clinph.2020.05.015

Cited by 34 publications

(25 citation statements)

References 36 publications

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“…True positive was defined as concordance between the FLAWS/MAP findings and resection with good surgical outcome, false positive as concordance between the FLAWS/MAP findings and resection with poor surgical outcome, true negative as non-concordance between the FLAWS/MAP findings and resection with poor surgical outcome, and false negative as non-concordance between FLAWS/MAP findings and resection with good surgical outcome. These definitions were based on those of previous reports in the literature ( 18 , 30 ).…”

Section: Methodsmentioning

confidence: 99%

Fluid and White Matter Suppression Imaging and Voxel-Based Morphometric Analysis in Conventional Magnetic Resonance Imaging-Negative Epilepsy

Sun

Yang

et al. 2021

Front. Neurol.

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Purpose: Delineation of subtle lesions in magnetic resonance imaging (MRI)-negative patients is of great importance in preoperative epilepsy evaluation. The aim of our study was to explore the diagnostic value of the novel fluid and white matter suppression (FLAWS) sequence in comparison with a voxel-based MRI postprocessing morphometric analysis program (MAP) in a consecutive cohort of non-lesional patients.Methods: Surgical candidates with a negative finding on an official neuroradiology report were enrolled. High-resolution FLAWS image and MAP maps generated based on high-resolution three-dimensional (3D) T1 image were visually inspected for each patient. The findings of FLAWS or MAP-positive (FLAWS/MAP+) regions were compared with the surgical resection cavity in correlation with surgical outcome and pathology.Results: Forty-five patients were enrolled; the pathological examination revealed focal cortical dysplasia (FCD) in 32 patients and other findings in 13 patients. The positive rate, sensitivity, and specificity were 48.9%, 0.43, and 0.87, respectively, for FLAWS and 64.4%, 0.57, and 0.8, respectively, for MAP. Concordance between surgical resection and FLAWS+ or MAP+ regions was significantly associated with a seizure-free outcome (FLAWS: p = 0.002; MAP: p = 0.0003). A positive finding in FLAWS and MAP together with abnormalities in the same gyrus (FLAWS–MAP gyral+) was detected in 31.1% of patients. FLAWS+ only and MAP+ only were found in 7 (15.5%) and 14 (31.1%) patients, respectively.Conclusions: FLAWS showed a promising value for identifying subtle epileptogenic lesions and can be used as a complement to current MAP in patients with MRI-negative epilepsy.

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Section: Methodsmentioning

confidence: 99%

Fluid and White Matter Suppression Imaging and Voxel-Based Morphometric Analysis in Conventional Magnetic Resonance Imaging-Negative Epilepsy

Sun

Yang

et al. 2021

Front. Neurol.

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“…This development has the potential to lead to important progress in epilepsy evaluations. More importantly, estimation of the seizure onset zone from scalp EEG can be inaccurate because of limits in EEG sensitivity and accuracy, requiring complementary intracranial recordings (Rossi Sebastiano et al, 2020). While optimally placed intracranial EEG electrodes can pinpoint the sources of epileptic activity accurately, only limited number of subregions of the brain can be mapped.…”

Section: Introductionmentioning

confidence: 99%

On the clinical benefit of on-scalp MEG: A modeling study of on-scalp MEG epileptic activity source estimation ability

Westin

Beniczky

Hämäläinen

2022

Preprint

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Objective: Whole-head on scalp magnetoencephalography (osMEG) is a novel, cutting-edge functional neuroimaging technique that positions MEG sensors closer to the cortical sources. OsMEG allows both for free head movements and improved spatial resolution compared to conventional MEG. OsMEG thus might improve clinical epilepsy evaluations. However, it remains largely unknown how osMEG characterizes epileptic activity. Here, we aimed to compare epileptic activity source estimation accuracy of osMEG, high-density EEG (hd-EEG), conventional MEG (convMEG) and subdural EEG (sbdEEG). Method: IED and seizure onset zone source estimations of osMEG, hdEEG, convMEG and sbdEEG were evaluated using equivalent current dipoles. Cancellation index of all non-invasive modalities were calculated and compared statistically. To further investigate any similarity between osMEG and sbdEEG, representational similarity analysis was used to compare IED source estimations of these two modalities. Results: We found that osMEG IED source estimations were significantly (p<0.05) better than both convMEG and hdEEG. Furthermore, osMEG mesial temporal lobe SOZ source estimations were superior to those of convMEG and hdEEG. OsMEG cancellation index did not differ significantly from convMEG. Interestingly, comparing osMEG and sbdEEG IED source estimation demonstrated that osMEG might be less sensitive to source directions than convMEG. Conclusion: We demonstrated that whole-head osMEG exhibited very accurate non-invasive IED and SOZ source estimations, better than both hd-EEG and convMEG. Significance: OsMEG has a promising potential to become a safe, highly sensitive neuroimaging modality for whole head epilepsy evaluations.

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“…EEG-fMRI had also been successfully used for localizing the EZ in patients with cortical and subcortical malformations such as focal cortical dysplasia (24), cortical tubers (25) and polymicrogyria [PMG; (26)]. Notwithstanding, the efficacy of this method is still under investigation and its sensitivity to epileptic sources is reportedly equal to or lower than other diagnostic methods (27). Recent work suggests the sensitivity of EEG-fMRI may be enhanced by taking into account the temporal dynamics of epileptic activity (28).…”

Section: Introductionmentioning

confidence: 99%

Interictal Epileptiform Discharge Dynamics in Peri-sylvian Polymicrogyria Using EEG-fMRI

et al. 2021

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Polymicrogyria (PMG) is a common malformation of cortical development associated with a higher susceptibility to epileptic seizures. Seizures secondary to PMG are characterized by difficult-to-localize cerebral sources due to the complex and widespread lesion structure. Tracing the dynamics of interictal epileptiform discharges (IEDs) in patients with epilepsy has been shown to reveal the location of epileptic activity sources, crucial for successful treatment in cases of focal drug-resistant epilepsy. In this case series IED dynamics were evaluated with simultaneous EEG-fMRI recordings in four patients with unilateral peri-sylvian polymicrogyria (PSPMG) by tracking BOLD activations over time: before, during and following IED appearance on scalp EEG. In all cases, focal BOLD activations within the lesion itself preceded the activity associated with the time of IED appearance on EEG, which showed stronger and more widespread activations. We therefore propose that early hemodynamic activity corresponding to IEDs may hold important localizing information potentially leading to the cerebral sources of epileptic activity. IEDs are suggested to develop within a small area in the PSPMG lesion with structural properties obscuring the appearance of their electric field on the scalp and only later engage widespread structures which allow the production of large currents which are recognized as IEDs on EEG.

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Identifying the epileptogenic zone by four non-invasive imaging techniques versus stereo-EEG in MRI-negative pre-surgery epilepsy patients

Cited by 34 publications

References 36 publications

Fluid and White Matter Suppression Imaging and Voxel-Based Morphometric Analysis in Conventional Magnetic Resonance Imaging-Negative Epilepsy

Fluid and White Matter Suppression Imaging and Voxel-Based Morphometric Analysis in Conventional Magnetic Resonance Imaging-Negative Epilepsy

On the clinical benefit of on-scalp MEG: A modeling study of on-scalp MEG epileptic activity source estimation ability

Interictal Epileptiform Discharge Dynamics in Peri-sylvian Polymicrogyria Using EEG-fMRI

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