To improve the conditioning of GRAPPA enabled in-plane
acceleration by using phase encoding shifts of spatially neighbouring slices.
Parallel imaging offers the possibility to reduce
acquisition time or echo train lengths needed to fully encode a given object. New
k-space trajectories and reconstruction techniques offer the possibility of
large acceleration factors in the slice direction (in the case of SMS) or in either of the two phase
encoding directions in volumetric imaging. While 2D and 3D
reconstructions can be seen on a common framework, it is not straightforward to, in conventional multi-slice
imaging, have more than 3-4 fold inplane acceleration.
