Dynamic Field Mapping and Motion Correction Using Interleaved Double Spin-Echo Diffusion MRI

Abstract

Diffusion MRI (dMRI) analysis requires combining data from many images and this generally requires corrections for image distortion and for subject motion during what may be a prolonged acquisition. Particularly in non-brain applications, changes in pose such as respiration can cause image distortion to be time varying, impeding static field map-based correction. In addition, motion and distortion correction is challenging at high b-values due to the low signal-to-noise ratio (SNR). In this work we develop a new approach that breaks the traditional “one-volume, one-weighting” paradigm by interleaving low-b and high-b slices, and combine this with a reverse phase-encoded double-spin echo sequence. Interspersing low and high b-value slices ensures that the low-b, high-SNR data is in close spatial and temporal proximity to support dynamic field map estimation from the double spin-echo acquisition and image-based motion correction. This information is propagated to high-b slices with interpolation across space and time. The method is tested in the challenging environment of fetal dMRI and it is demonstrated using data from 8 pregnant volunteers that combining dynamic distortion correction with slice-by-slice motion correction increases data consistency to facilitate advanced analyses where conventional methods fail.