Bz-SNR-Enhanced Echo-Shifted Incoherent Steady State Imaging for Electrical Conductivity Mapping

Hyunyeol Lee¹, Woo Chul Jeong², Hyung Joong Kim², Eung Je Woo², Jaeseok Park¹

Magnetic resonance electrical impedance tomography (MREIT) was recently introduced to achieve high spatial resolution, wherein the internal magnetic flux density (Bz) induced by current injection results from image phases and electrical conductivity is then calculated using the harmonic Bz algorithm. To achieve accurate conductivity distribution in tissues, a high signal-to-noise ratio (SNR) in Bz is critical, which is proportional to the product of current injection time (TC) and SNR in magnitude image. To effectively enhance the SNR of Bz in MREIT and speed up data acquisition, in this work we develop a Bz-SNR-optimized echo-shifted incoherent steady state imaging pulse sequence for accurate quantification of electrical conductivity, wherein free induction decay (FID) signals experience multiple current injections to form an echo without apparent loss of signals while retaining high imaging efficiency.