@article{GoksuSEHT2017,
  title = {{Sensitivity analysis of magnetic field measurements for magnetic resonance electrical impedance tomography (MREIT)}},
  journal = {{Magnetic Resonance in Medicine}},
  abstract = {{Purpose Clinical use of magnetic resonance electrical impedance tomography (MREIT) still requires significant sensitivity improvements. Here, the measurement of the current-induced magnetic field ($\Delta$Bz,c) is improved using systematic efficiency analyses and optimization of multi-echo spin echo (MESE) and steady-state free precession free induction decay (SSFP-FID) sequences. Theory and Methods Considering T1, T2, and math formula relaxation in the signal-to-noise ratios (SNRs) of the MR magnitude images, the efficiency of MESE and SSFP-FID MREIT experiments, and its dependence on the sequence parameters, are analytically analyzed and simulated. The theoretical results are experimentally validated in a saline-filled homogenous spherical phantom with relaxation parameters similar to brain tissue. Measurement of $\Delta$Bz,c is also performed in a cylindrical phantom with saline and chicken meat. Results The efficiency simulations and experimental results are in good agreement. When using optimal parameters, $\Delta$Bz,c can be reliably measured in the phantom even at injected current strengths of 1 mA or lower for both sequence types. The importance of using proper crusher gradient selection on the phase evolution in a MESE experiment is also demonstrated. Conclusion The efficiencies observed with the optimized sequence parameters will likely render in-vivo human brain MREIT feasible.}},
  volume = {79},
  number = {2},
  pages = {748--760},
  year = {2018},
  slug = {goksuseht2017},
  author = {G\"oksu, C and Scheffler, K and Ehses, P and Hanson, LG and Thielscher, A}
}