A new protocol for the rapid generation of accurate anatomically realistic Finite Element Meshes of the head from T1 MRI scans

Reconstruction of images in Electrical Impedance Tomography (EIT) of brain function in the adult head benefits from the use of accurate numerical models, which may utilize meshes created by the Finite Element Method (FEM). Previously, these have been produced by manual segmentation and parametric representation of surfaces which were later meshed, but this was time consuming and required CAD specialist expertise; as a result a single standard mesh was used for all subjects and this may have introduced errors. We demonstrate a new mesh generation procedure, which employed the freely available BrainSuite segmentation and Cubit meshing software. By this procedure, anatomically accurate finite element meshes of the head can be produced from T1 MRI scans in less than an hour. Acceptable images of test objects in the human head could be obtained with image reconstruction with the new meshes using experimental tank and simulated data. For uniform mesh density, the optimum element size was 7 mm, or 7mm for scalp, 5mm for skull and CSF and a bias factor 1.4 for brain for variable sizing. This appears to provide a practicable and rapid new method which could be used to provide individual subject FEM meshes without special expertise for EIT imaging in the head or elsewhere in the body if accurate individual meshes are required.