Combined Planar Magnetic Induction Tomography for Local Detection of Intracranial Hemorrhage

Abstract

Magnetic induction tomography (MIT) is a contactless and harmless technique for intracranial hemorrhage detection. Due to the low electrical conductivity of biological tissues, the phase shift signals are very weak. To improve the sensitivity of the phase shift signals and achieve the local detection of intracranial hemorrhage, a planar MIT method is proposed. The coil parameters were optimized based on the sensitivity analysis. The performance of single planar and combined planar MITs was investigated with a 3-D anatomical head model. Two evaluation indexes, correlation coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text {cc}_{\text {ima}}$ </tex-math></inline-formula> and localization error <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L_{e}$ </tex-math></inline-formula> , were introduced to evaluate the imaging quality. Finally, experimental tests were carried out to verify the ability of combined planar MIT for hemorrhage detection. The simulation results indicate that the combined planar MIT has better imaging quality and distinguishing ability for the hemorrhage with different deviation positions, depths, and volumes. For the 8-mL hemorrhage, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text {cc}_{\text {ima}}$ </tex-math></inline-formula> of combined planar MIT is increased by 40.2%, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L_{e}$ </tex-math></inline-formula> is reduced by 77.8% compared with single planar MIT. The experimental results indicate that a 16-mL hemorrhage can be reconstructed, and the change in position can be distinguished by combined planar MIT. The study demonstrates that combined planar MIT is a feasible method for hemorrhage detection. The proposed method provides a portable solution for local detection of intracranial hemorrhage and promotes the practical application of MIT in biomedical imaging.