  Purpose: Cross-term spatiotemporal encoding-xSPEN-is a single-shot imaging
approach with exceptional resilience to field heterogeneities: its images do
not require a priori information nor use post-acquisition corrections, to
deliver faithfully the spatial distribution. xSPEN, however, suffers from SNR
penalties due to its non-Fourier nature and due to diffusion losses- specially
when desiring high resolution. This study explores partial Fourier transform
approaches that acting along either the readout or the spatiotemporally-encoded
dimensions, reduce these penalties.
  Methods: xSPEN uses an orthogonal gradient to read, in direct space, the
lowbandwidth dimension. This changes substantially the nature of partial
Fourier acquisitions vis-a-vis conventional imaging counterparts. A suitable
theoretical analysis, however, allows one to implement these procedures along
either the low-bandwidth or readout axes.
  Results: Partial Fourier single-shot xSPEN methods are illustrated on
preclinical and human scanners. Owing to their reduction in the experimental
acquisition times, these methods provide substantial sensitivity gains
vis-a-vis previous implementations for a given targeted in-plane resolution.
The magnitude of these gains is as expected.
  Conclusion: Partial Fourier approaches, particularly when implemented along
the xSPEN axis, can provide substantial sensitivity advantages at minimal costs
in the operation of the single-shot experiments.
