Diffusion MRI Based on SPatio-temporal ENcoding: Analytical Description and Validation

Eddy Solomon¹, Noam Shemesh¹, Lucio Frydman¹

Single-scan SPatio-temporal ENcoding (SPEN) MRI is explored as an alternative for acquiring diffusion-weighted images. As these experiments involve the combined application of frequency-swept pulses and magnetic field gradients, the Stejskal-Tanner derivation of the b-values is no longer valid; in addition to diffusion-sensitizing gradients, SPEN’s gradients and swept RF fields impose additional spatially-dependent diffusion weightings over the sample. These effects, as well as potential cross-talk terms between the diffusion-sensitizing and SPEN gradients, are calculated in this study. Excellent agreement is then found between the analytical predictions and SPEN diffusion experiments in isotropic phantoms and anisotropic systems including spinal-cords.