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GdM+03b

S. I. Goncalves, J. C. de Munck, J. P. Verbunt, F. Bijma, R. M. Heethaar, F. Lopes da Silva. In vivo measurement of the brain and skull resistivities using an EIT-based method and realistic models for the head. IEEE Trans Biomed Eng, 50(6):754-767, 2003.

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Abstract

In vivo measurements of equivalent resistivities of skull (rho(skull)) and brain (rho(brain)) are performed for six subjects using an electric impedance tomography (EIT)-based method and realistic models for the head. The classical boundary element method (BEM) formulation for EIT is very time consuming. However, the application of the Sherman-Morrison formula reduces the computation time by a factor of 5. Using an optimal point distribution in the BEM model to optimize its accuracy, decreasing systematic errors of numerical origin, is important because cost functions are shallow. Results demonstrate that rho(skull)/rho(brain) is more likely to be within 20 and 50 rather than equal to the commonly accepted value of 80. The variation in rho(brain)(average = 301 omega x cm, SD = 13\%) and rho(skull)(average = 12230 omega x cm, SD = 18\%) is decreased by half, when compared with the results using the sphere model, showing that the correction for geometry errors is essential to obtain realistic estimations. However, a factor of 2.4 may still exist between values of rho(skull)/rho(brain) corresponding to different subjects. Earlier results show the necessity of calibrating rho(brain) and rho(skull) by measuring them in vivo for each subject, in order to decrease errors associated with the electroencephalogram inverse problem. We show that the proposed method is suited to this goal

Keywords

[ Adult ] [ Brain/*physiology ] [ Brain mapping/methods ] [ Comparative study ] [ Computer simulation ] [ Electric impedance/*diagnostic use ] [ Electroencephalography/methods ] [ Female ] [ Head/*physiology ] [ Human ] [ Male ] [ *models ] [ Biological ] [ Reproducibility of results ] [ Sensitivity and specificity ] [ Skull/*physiology ] [ Support ] [ Non-u.s. gov't ] [ Tomography/methods ]

Contact

S.I. Goncalves
J.C. de Munck
J. P. Verbunt
F. Bijma
R.M. Heethaar
F.H. Lopes da Silva

BibTex Reference

@article{GdM+03b,
   Author = {Goncalves, S. I. and de Munck, J. C. and Verbunt, J. P. and Bijma, F. and Heethaar, R. M. and Lopes da Silva, F.},
   Title = {In vivo measurement of the brain and skull resistivities using an {EIT}-based method and realistic models for the head},
   Journal = {IEEE Trans Biomed Eng},
   Volume = {50},
   Number = {6},
   Pages = {754--767},
   Year = {2003}
}

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