Ultrasound modulated electrical impedance tomography by contrast libraries of measurements variation

摘要

Electrical impedance tomography (EIT) is a relatively new imaging technique developed in the recent years. However, due to the ill-poseness of the inverse problem, spatial resolution of the reconstructed image is not high. Acousto-electric effect depicts that focused ultrasound alters the conductivity in the focal region. Based on the acousto-electric effect, ultrasound modulated electrical impedance tomography (UMEIT) is proposed. Using location information related to the original conductivity in the focused ultrasound area, contrast libraries of the measurements variation from background to object have been established, then the point-wise data of the boundary measurement are compared with the contrast libraries, and image of conductivity distribution is reconstructed with binarization directly without resorting to inverse algorithm. Finally the simulation results validate the effectiveness of the proposed method by the contrast libraries of the measurements variation. This method can reduce the effect of electrode location on sensitivity to improve the resolution, especially in the center of the imaging object, and avoid the ill-poseness of inverse problem.