Title: Diffusion MRI measurements in challenging head and brain regions via cross-term spatiotemporally encoding,
Abstract: Cross-term spatiotemporal encoding (xSPEN) is a recently introduced imaging
approach delivering single-scan 2D NMR images with unprecedented resilience to
field inhomogeneities. The method relies on performing a pre-acquisition
encoding and a subsequent image read out while using the disturbing frequency
inhomogeneities as part of the image formation processes, rather than as
artifacts to be overwhelmed by the application of external gradients. This
study introduces the use of this new single-shot MRI technique as a
diffusion-monitoring tool, for accessing regions that have hitherto been
unapproachable by diffusion-weighted imaging (DWI) methods. In order to achieve
this, xSPEN MRIs intrinsic diffusion weighting effects are formulated using a
customized, spatially-localized b-matrix analysis; with this, we devise a novel
diffusion-weighting scheme that both exploits and overcomes xSPENs strong
intrinsic weighting effects. The ability to provide reliable and robust
diffusion maps in challenging head and brain regions, including the eyes and
the optic nerves, is thus demonstrated in humans at 3T; new avenues for imaging
other body regions are also briefly discussed.