Electric Field Mapping in ex vivo Anisotropic Muscle Tissue Using DT-MREIT

Abstract

Accurate coverage of tissue with a sufficiently large electric field is one of the key conditions for successful electroporation. Magnetic resonance electrical impedance tomography (MREIT) provides a means to map the electric filed distribution during electroporation. To estimate the electric field strength, the magnetic flux density data induced by the electroporation pulses are measured from MREIT scans during electroporation. Since biological tissues such as skeletal muscle are anisotropic, we propose a novel MREIT technique to map the electric field in anisotropic as well as isotropic regions. We utilize the anisotropic conductivity estimation method based on the lately developed DT-MREIT technique where diffusion tensor imaging is combined with MREIT. To estimate the current density in an optimal way, we adopted the projected current density estimation algorithm. From ex vivo experiments using bovine muscle tissues, we found that the new method produces electric field maps with a wider coverage of electroporation than the previous method. The results suggest that it is important to properly handle the effects of the tissue anisotropy for more accurate mapping of electric field during electroporation.