Electrical Shocked Mouse Model

Overview

Significant injuries can be caused by high voltage electrical shocks, which can result in cutaneous burns, irreversible tissue damage and even death. Finite Element (FE) modelling based on CT and cryosection images of a mouse has allowed researchers to virtually investigate tissue damage and its relation to Joule heating amounts and electric shocks. Simpleware software was used to segment scan images for export as robust FE meshes to COMSOL Multiphysics®, where thermal analysis of tissue damage was carried out. This study demonstrates the benefits of image-based modelling for accurately reconstructing experimental tests involving anatomical data.

Characteristics:

  • Data acquired from Digimouse: 3D Mouse Atlas - based on a set of co-registered CT & cryosection images of a male mouse
  • Simpleware ScanIP used to segment 9 regions of interest including hard and soft tissue
  • Extra parts added in ScanIP using 3D editing tools
  • Volume mesh with material properties generated in Simpleware +FE
  • Direct export to COMSOL Multiphysics® for simulation

Thanks to

The Catholic University of America: T. T. A. Nguyen • J. C. Ramella-Roman
Burn Center, Washington Medical Center: L. Moffat • J. Shupp

Image Processing

A male mouse body, including skin and several organs, was visualized in ScanIP from free online co-registered CT and cryosection images.

Semi-automated segmentation tools were used to obtain nine structures, including the heart, lungs, stomach, liver, kidneys, bladder, and testes. Boolean operations were also applied in ScanIP to aid segmentation, while filters were used to smooth surface structures. 3D editing tools were used to add four parts, including fat and muscle layers, aorta branches and electrodes to the model, with the aim of simulating preferential pathways and electrical damage.

Mesh Generation

The segmented data was volume meshed in Simpleware ScanIP +FE using the +FE Free meshing algorithm. A compound coarseness of minus 40 was selected to ensure a sufficient quality mesh, which was generated with conforming interfaces. The mesh contained 3,198,443 elements for all domains, with homogeneous material properties assigned to each organ.

Meshes were then exported to COMSOL Multiphysics® for voltage application and the simulation of bio-heat transfer.

FE Simulation

Thermal and electrical properties, including thermal and electrical conductivity, mass density and heat capacity were assigned to the mouse model in COMSOL. Physical functions of high voltage and Joule heating were then applied for simulation of heat energy distribution. The Bio-heat equation was used, and consideration was made of the cooling-down effect of blood flow on the skin. Results for electrical distribution and temperature were collected, and tissue damage temperature levels compared to experimental results and published data. A thermal camera was also used to confirm the model’s accuracy compared to experiments, with the FE simulation demonstrating the rich potential for future modelling.