Local grid refinement for low-frequency current computations in 3-D human anatomy models

The calculation of current densities in voxel-based high-resolution anatomy models allows insight in the current distribution inside the human body. The geometric complexity of the human body requires a very high resolution in order to properly resolve small organs. We present a local grid refinement scheme for low-frequency current calculations, allowing to finely resolve areas of particular interest. Using a Lagrange-multiplier approach, the whole model including the fine and coarse grid domains can be computed with only one solution of an algebraic system of equations. The presented approach is validated and tested on numerical examples.