A framework for modeling bioimpedance measurements of nonhomogeneous tissues: a theoretical and simulation study

Objective.Bioimpedance technology is experiencing an increased use to assess health in a wide range of new consumer, research and clinical applications. However, the interaction between tissues producing bioimpedance data is often unclear.Methods.This work provides a novel theoretical framework to model bioimpedance measurements of nonhomogeneous tissues. We consider five case studies to validate the usefulness of our approach against finite element model simulations.Results.Theoretical and FEM-simulated apparent resistance and reactance data were in good agreement, with a maximum relative errors <4% and <8%, respectively.Conclusion.The biophysics-driven framework developed provides compact analytical expressions to model nonhomogeneous bioimpedance measurements including multiple tissues with arbitrary shape and electrical properties. This work provides a new perspective to interpret nonhomogeneous bioimpedance measurements usingseries,parallel, andseries-parallelcircuit-like topology equivalents.Significance.Our framework is a new tool to better understand and describe complex nonhomogeneous biological measurements as, for example, cardiac, brain and respiratory applications using (non)invasive electrodes.