In Vivo Human Head Regional Conductivity Estimation Using A Three-sphere Model

Eriksen, K. Jeffrey

doi:10.1109/iembs.1990.691856

Cited by 7 publications

(7 citation statements)

References 2 publications

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“…Eriksen conducted a typical in vivo bEIT experiment using 4 subjects, 20 measuring electrodes, one current injection pair, and several frequencies. The best fit for the data in a three layer spherical model produced an average of 4 mS/m for the skull and 0.53S/m for the scalp conductivities [33]. De Munck et al proved the stability of the bEIT problem (in contrast with the ill posed imaging EIT method) through simulations [50].…”

Section: Introductionmentioning

confidence: 99%

“…From these boundary voltage measurements, it is possible to reconstruct the internal volumetric conductivity distribution, either voxel to voxel basis (imaging EIT, [32]), or just a subset of the regional tissue parameters (parametric or bounded EIT [16], [33]- [35]). An advantage of the bounded EIT (bEIT) approach is that it is able to characterize the conductivity of the most resistive (i.e., the skull) that is invisible to MRI Diffusion Tensor Imaging (DTI) [36].…”

Section: Introductionmentioning

confidence: 99%

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Skull Modeling Effects in Conductivity Estimates Using Parametric Electrical Impedance Tomography

Fernandez-Corazza

Turovets

Luu

et al. 2018

IEEE Trans. Biomed. Eng.

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Abstract-Objective: To estimate scalp, skull, compact bone and marrow bone electrical conductivity values based on Electrical Impedance Tomography (EIT) measurements, and to determine the influence of skull modeling details on the estimates. Methods: We collected EIT data with 62 current injection pairs and built five 6-8 million finite element (FE) head models with different grades of skull simplifications for four subjects, including three whose head models serve as Atlas in the scientific literature and in commercial equipment (Colin27 and EGI's Geosource atlases). We estimated electrical conductivity of the scalp, skull, marrow bone and compact bone tissues for each current injection pair, each model, and each subject. We also provide subject specific conductivity estimates for widely used Atlas head models.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Skull Modeling Effects in Conductivity Estimates Using Parametric Electrical Impedance Tomography

Fernandez-Corazza

Turovets

Luu

et al. 2018

IEEE Trans. Biomed. Eng.

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“…Therefore, we varied the skull conductivity only in the male model. The upper limit of the GM-to-skull conductivity ratio is taken to be 290 [44], and the lower limit is taken to be 18.7 [41]. More sophisticated skull models have multi-layer structure and/or anisotropy [45].…”

Section: ) Skull Conductivitymentioning

confidence: 99%

Effect of anatomical variability on neural stimulation strength and focality in electroconvulsive therapy (ECT) and magnetic seizure therapy (MST)

Deng

Lisanby

Peterchev

2009

2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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We present a quantitative comparison of two metrics-neural stimulation strength and focality-in electrocon-vulsive therapy (ECT) and magnetic seizure therapy (MST) using finite-element method (FEM) simulation in a spherical head model. Five stimulation modalities were modeled, including bilateral ECT, unilateral ECT, focal electrically administered seizure therapy (FEAST), and MST with circular and double-cone coils, with stimulation parameters identical to those applied in clinical practice. We further examine the effect on the stimulation metrics of individual-, sex- and age-related variability in tissue layer thickness and conductivity. Neural stimulation by MST is shown to be more focal and superficial than ECT. This result suggests that it may be advantageous to reduce the current used in ECT. The stimulation strength in MST is also less sensitive to variations in head geometry and tissue conductivity than in ECT. Individualization of pulse amplitude in both ECT and MST could compensate for anatomical variability, which could lead to more consistent clinical outcomes.

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“…Previous bEIT estimates used three layer spherical [10] or BEM [2,11,12] models with pointwise or triangular electrodes, and, in [11,12], only one unknown. A bEIT study using FEM and two unknowns was recently reported [13].…”

Section: Introductionmentioning

confidence: 99%

Effects of Head Model Inaccuracies on Regional Scalp and Skull Conductivity Estimation Using Real EIT Measurements

Fernandez-Corazza

Turovets²,

Govyadinov

et al. 2016

IFMBE Proceedings

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Abstract-we estimate the scalp and skull conductivities on two healthy adults, based on bounded (or parametric) Electrical Impedance Tomography (bEIT) measurements, and using 62 current injection pairs of a high dense 128 sensor array. We compare the estimates obtained with three different electrode models: pointwise, volumetric, and the Complete Electrode Model (CEM). We also analyze the influence of the skull details and the cerebrospinal fluid (CSF). The estimated scalp (skull) conductivities for these two subjects were ~0.4 and ~0.3 S/m (~0.0045 and ~0.005 S/m), similar for all three electrode models (within 8%). Volumetric and CEM models resulted in a better fit to real data. A model of nested and closed surfaces (no skull holes) resulted in a significant overestimation (~23%) of the skull conductivity. Moreover, neglecting the CSF resulted in an extra 28% overestimation of the skull conductivity. This clearly shows the need of precise head modeling for bEIT.

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In Vivo Human Head Regional Conductivity Estimation Using A Three-sphere Model

Cited by 7 publications

References 2 publications

Skull Modeling Effects in Conductivity Estimates Using Parametric Electrical Impedance Tomography

Skull Modeling Effects in Conductivity Estimates Using Parametric Electrical Impedance Tomography

Effect of anatomical variability on neural stimulation strength and focality in electroconvulsive therapy (ECT) and magnetic seizure therapy (MST)

Effects of Head Model Inaccuracies on Regional Scalp and Skull Conductivity Estimation Using Real EIT Measurements

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