Skull Modeling Effects in Conductivity Estimates Using Parametric Electrical Impedance Tomography

Fernandez-Corazza, Mariano; Turovets, Sergei; Luu, Phan; Price, Nick; Muravchik, Carlos H.; Tucker, Don M.

doi:10.1109/tbme.2017.2777143

Cited by 33 publications

(37 citation statements)

References 97 publications

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“…Similar conductivity sensitivity effects have been found previously using either the FEM or the finite difference method (FDM; Gençer & Acar, 2004;Ramon et al, 2004;Wendel et al, 2008;Vallaghé & Clerc, 2009;Vorwerk et al, 2014Vorwerk et al, , 2019Azizollahi et al, 2016;Cuartas et al, 2019). Our results, therefore, support the importance of more realistic modeling of these inner brain tissue compartments that also strongly influence than the estimated individual conductivity parameters for the skull layer, as also shown by (Aydin et al, 2014;Fernández-Corazza et al, 2017). In the current study, we demonstrated this skull conductivity variability by a noninvasive estimation procedure using EMEG source analysis and highly detailed FEM head models in healthy participants.…”

Section: Effects Of Head Modeling and Modality On The P20/n20 Reconsupporting

confidence: 90%

“…Let us now discuss the quality of source reconstruction with regard to the source orientation and strength components, that is, the in target orientation have an even stronger impact on the optimized montages than slight changes in target location (Antonakakis et al, 2019;Dmochowski, Koessler, Norcia, Bikson, & Parra, 2017;Fernández-Corazza et al, 2017;Schmidt, Wagner, Burger, Rienen, & Wolters, 2015;Wagner et al, 2016). Concerning the impact of head model differences to the reconstructed source moments for the EW stimulation type, EMEG was overall more stable, also with regard to inter-subject variability, than EEG and MEG alone, as shown for 6CA_Cal versus 3CI_Cal in Figure 4b (middle and right columns) and for 6CA_Cal versus 3CI_41 or 6CA_41 in Figure 6 (left panel in middle and right columns).…”

Section: Effects Of Head Modeling and Modality On The P20/n20 Reconmentioning

confidence: 99%

“…As shown in Figure 4b (right column), the homogenized 3CI_Cal head model resulted for the majority of subjects in a higher source strength, especially for the EEG and to a lesser extent also for the MEG and EMEG modalities. Especially for the EEG and to a lesser degree for EMEG, this is caused by the lower values for calibrated skull conductivity for the 3CI_Cal when compared to the 6CA_Cal head models and by the current channeling due to the additional CSF compartment (Table 1 and Figure 3; see also Vorwerk et al, 2014Vorwerk et al, , 2019Rice et al, 2012;Güllmar et al, 2006Güllmar et al, , 2010Azizollahi et al, 2016;Fernández-Corazza et al, 2017;Cuartas et al, 2019). Furthermore, in Figure 6 (right column), an increase or decrease of source strength is related to whether the calibrated skull conductivity in Table I is lower or higher than the standard one, resp., further supporting the crucial role of skull conductivity.…”

Section: Effects Of Head Modeling and Modality On The P20/n20 Reconmentioning

confidence: 99%

“…As one of the important parameters of the head model, skull conductivity is known to vary inter-individually and to influence EEG, but not MEG reconstructions (Akalin Acar, Acar, & Makeig, 2016;Azizollahi, Darbas, Diallo, El Badia, & Lohrengel, 2018;Vorwerk et al, 2014Vorwerk et al, , 2019. The importance of individual skull conductivity on EEG and EMEG was emphasized in various studies (Akalin Acar et al, 2016;Aydin et al, 2014;Fernández-Corazza et al, 2017;Fuchs et al, 1998;Haueisen et al, 1997;Huang et al, 2007;Lew, Wolters, Anwander, et al, 2009;Montes-Restrepo et al, 2014;Roche-Labarbe et al, 2008;Vorwerk et al, 2019;Wolters, Lew, MacLeod, & Hämäläinen, 2010). Therefore, in our study and following the recommendations of (Aydin et al, 2014), individual skull conductivity will be estimated in a calibration procedure based on the SEP/SEF data.…”

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confidence: 99%

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The effect of stimulation type, head modeling, and combined EEG and MEG on the source reconstruction of the somatosensory P20/N20 component

Antonakakis

Schrader

Wollbrink

et al. 2019

Human Brain Mapping

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Modeling and experimental parameters influence the Electro‐ (EEG) and Magnetoencephalography (MEG) source analysis of the somatosensory P20/N20 component. In a sensitivity group study, we compare P20/N20 source analysis due to different stimulation type (Electric‐Wrist [EW], Braille‐Tactile [BT], or Pneumato‐Tactile [PT]), measurement modality (combined EEG/MEG – EMEG, EEG, or MEG) and head model (standard or individually skull‐conductivity calibrated including brain anisotropic conductivity). Considerable differences between pairs of stimulation types occurred (EW‐BT: 8.7 ± 3.3 mm/27.1° ± 16.4°, BT‐PT: 9 ± 5 mm/29.9° ± 17.3°, and EW‐PT: 9.8 ± 7.4 mm/15.9° ± 16.5° and 75% strength reduction of BT or PT when compared to EW) regardless of the head model used. EMEG has nearly no localization differences to MEG, but large ones to EEG (16.1 ± 4.9 mm), while source orientation differences are non‐negligible to both EEG (14° ± 3.7°) and MEG (12.5° ± 10.9°). Our calibration results show a considerable inter‐subject variability (3.1–14 mS/m) for skull conductivity. The comparison due to different head model show localization differences smaller for EMEG (EW: 3.4 ± 2.4 mm, BT: 3.7 ± 3.4 mm, and PT: 5.9 ± 6.8 mm) than for EEG (EW: 8.6 ± 8.3 mm, BT: 11.8 ± 6.2 mm, and PT: 10.5 ± 5.3 mm), while source orientation differences for EMEG (EW: 15.4° ± 6.3°, BT: 25.7° ± 15.2° and PT: 14° ± 11.5°) and EEG (EW: 14.6° ± 9.5°, BT: 16.3° ± 11.1° and PT: 12.9° ± 8.9°) are in the same range. Our results show that stimulation type, modality and head modeling all have a non‐negligible influence on the source reconstruction of the P20/N20 component. The complementary information of both modalities in EMEG can be exploited on the basis of detailed and individualized head models.

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Section: Effects Of Head Modeling and Modality On The P20/n20 Reconsupporting

confidence: 90%

Section: Effects Of Head Modeling and Modality On The P20/n20 Reconmentioning

confidence: 99%

Section: Effects Of Head Modeling and Modality On The P20/n20 Reconmentioning

confidence: 99%

mentioning

confidence: 99%

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The effect of stimulation type, head modeling, and combined EEG and MEG on the source reconstruction of the somatosensory P20/N20 component

Antonakakis

Schrader

Wollbrink

et al. 2019

Human Brain Mapping

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“…Electrical impedance tomography (EIT) is a relatively new technique that has emerged as a potential solution to provide better spatial resolution within 3D tissue cultures. However, most recent efforts in EIT have been focused on its use in vivo and as a medical diagnostic, where electrodes are placed on the body to obtain an image and health status of an organ of interest (Fernandez-Corazza et al, 2018;Schwartz, Chauhan, & Sadleir, 2018;Sun, Yue, Hao, Cui, & Wang, 2019).…”

Section: D Impedance Tomographymentioning

confidence: 99%

Three‐Dimensional (3D) cell culture monitoring: Opportunities and challenges for impedance spectroscopy

León

Pupovac

McArthur

2020

Biotech & Bioengineering

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Three‐dimensional (3D) cell culture has developed rapidly over the past 5–10 years with the goal of better replicating human physiology and tissue complexity in the laboratory. Quantifying cellular responses is fundamental in understanding how cells and tissues respond during their growth cycle and in response to external stimuli. There is a need to develop and validate tools that can give insight into cell number, viability, and distribution in real‐time, nondestructively and without the use of stains or other labelling processes. Impedance spectroscopy can address all of these challenges and is currently used both commercially and in academic laboratories to measure cellular processes in 2D cell culture systems. However, its use in 3D cultures is not straight forward due to the complexity of the electrical circuit model of 3D tissues. In addition, there are challenges in the design and integration of electrodes within 3D cell culture systems. Researchers have used a range of strategies to implement impedance spectroscopy in 3D systems. This review examines electrode design, integration, and outcomes of a range of impedance spectroscopy studies and multiparametric systems relevant to 3D cell cultures. While these systems provide whole culture data, impedance tomography approaches have shown how this technique can be used to achieve spatial resolution. This review demonstrates how impedance spectroscopy and tomography can be used to provide real‐time sensing in 3D cell cultures, but challenges remain in integrating electrodes without affecting cell culture functionality. If these challenges can be addressed and more realistic electrical models for 3D tissues developed, the implementation of impedance‐based systems will be able to provide real‐time, quantitative tracking of 3D cell culture systems.

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Safety of slow‐pulsed transcranial electrical stimulation in acute spike suppression

Holmes

Feng

Wise

et al. 2019

Ann Clin Transl Neurol

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We examined the effects of slow‐pulsed transcranial electrical stimulation (TES) in suppressing epileptiform discharges in seven adults with refractory epilepsy. An MRI‐based realistic head model was constructed for each subject and co‐registered with 256‐channel dense EEG (dEEG). Interictal spikes were localized, and TES targeted the cortical source of each subject's principal spike population. Targeted spikes were suppressed in five subject's (29/35 treatment days overall), and nontargeted spikes were suppressed in four subjects. Epileptiform activity did not worsen. This study suggests that this protocol, designed to induce long‐term depression (LTD), is safe and effective in acute suppression of interictal epileptiform discharges.

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Skull Modeling Effects in Conductivity Estimates Using Parametric Electrical Impedance Tomography

Cited by 33 publications

References 97 publications

The effect of stimulation type, head modeling, and combined EEG and MEG on the source reconstruction of the somatosensory P20/N20 component

The effect of stimulation type, head modeling, and combined EEG and MEG on the source reconstruction of the somatosensory P20/N20 component

Three‐Dimensional (3D) cell culture monitoring: Opportunities and challenges for impedance spectroscopy

Safety of slow‐pulsed transcranial electrical stimulation in acute spike suppression

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