Abstract
A realistically shaped model of the head, consisting of tetrahedral elements, is used to investigate the influence of inhomogeneities in the volume conductor (e.g., ventricles and holes) on EEG and MEG. The potential is computed using the finite-element method. The magnetic field is calculated from this potential distribution, applying the law of Biot-Savart.
In order to study the influence of the ventricles, computations are carried out using two models: one in which the elements within the ventricles are given the same conductivity as the brain and one in which these elements have a higher conductivity. The influence of holes in the skull layer is examined by giving some elements in the skull layer the same conductivity as that of the brain.
The geometry of compartments is obtained semiautomatically from Magnetic Resonance Imaging (MRI) scans. The surface of the ventricles is obtained by manually selecting points on the interface between ventricle and brain. The computation time depends on the total number of tetrahedrons. Therefore, the vertices are distributed in, such a way that a sufficiently high accuracy is obtained with as few tetrahedrons as possible.
In order to study the influence of the ventricles, computations are carried out using two models: one in which the elements within the ventricles are given the same conductivity as the brain and one in which these elements have a higher conductivity. The influence of holes in the skull layer is examined by giving some elements in the skull layer the same conductivity as that of the brain.
The geometry of compartments is obtained semiautomatically from Magnetic Resonance Imaging (MRI) scans. The surface of the ventricles is obtained by manually selecting points on the interface between ventricle and brain. The computation time depends on the total number of tetrahedrons. Therefore, the vertices are distributed in, such a way that a sufficiently high accuracy is obtained with as few tetrahedrons as possible.
| Original language | English |
|---|---|
| Pages (from-to) | 233-233 |
| Journal | Brain topography |
| Volume | 9 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 8 Mar 1997 |
| Event | 7th International ISBET Congress 1996 - Rio de Janeiro, Brazil Duration: 14 Oct 1996 → 17 Oct 1996 Conference number: 7 |