An inhomogeneous soft tissue model for measurement of electric fields induced by pulsed magnetic fields

Calculation of the electric field induced into an inhomogeneous medium by time-varying magnetic fields is very complicated. Therefore results of magnetic nerve stimulation are not always predictable. Previously proposed inhomogeneous models composed of a nonconducting medium and an electrolyte solution are appropriate only for nerves adjacent to bony structures. In this report, the authors propose a new inhomogeneous model which is appropriate for nerves far from bone. The model consists of double troughs. The outside and inside troughs are filled with saline solutions of 0.1% and 0.9%, respectively. The electric fields induced into this model by a figure-eight coil are measured, and its first spatial derivatives are calculated. Unlike those induced into a homogeneous model, they shift towards a 0.9% solution