Improved Magneto-Acousto-Electrical Computed Tomography (MAE-CT) With Multi-Angle Plane Wave Excitation.

Abstract

As a tissue conductivity imaging method, magneto-acousto-electric tomography (MAET) has the advantage of high axial spatial resolution compared with traditional electrical impedance imaging methods. However, it has the problems of difficulty in imaging targets with irregular conductivity distribution and poor lateral spatial resolution. Although the rotation-based MAET method can partly solve the irregular target problem, there is still a poor imaging signal-to-noise ratio (SNR) problem. Our previous study established a framework of an innovative MAET method, which has a very similar imaging theory and reconstruction algorithm to those of computed tomography (CT). Therefore, we name the method magneto-acoustic-electric computed tomography (MAE-CT). This paper proposes an improved implementation of MAE-CT based on multi-angle plane wave excitation. This method combines the electronic steering of the linear array transducer with the mechanical rotation to increase the number of projection angles while keeping the imaging complexity. In this study, we first established a finite element simulation model to verify the method's feasibility. Then phantom experiments were conducted to systematically investigate the performance of the proposed method. Finally, in vitro liver tissue experiment was conducted to further explore the feasibility of the method. The experimental results show that our method improves both the SNR and spatial resolution of the reconstructed image. For the phantom results, this method can detect conductivity of 0.67 S/m in an area with a size of 2 mm. To the best of our knowledge, this is the best result of spatial resolution available for MAET.