Coil-by-coil image reconstruction with SMASH

The SiMultaneous Acquisition of Spatial Harmonics (SMASH) technique uses li near combinations of undersampled datasets from the component coils of an R F coil array to reconstruct fully sampled composite datasets in reduced ima ging times. In previously reported implementations, SMASH reconstructions w ere designed to reproduce the images that would otherwise be obtained by si mple sums of fully gradient encoded component coil images. This strategy ha s left SMASH images vulnerable to phase cancellation artifacts when the sen sitivities of RF coil array elements are not suitably phase-aligned. In ful ly gradient encoded imaging schemes these artifacts can be eliminated using a variety of methods for combining the individual coil images, including m atched filter combinations as well as sum of squares combinations. Until no w, these reconstruction schemes have been unavailable to SMASH reconstructi ons as SMASH produced a final composite image directly from the raw compone nt coil k-space datasets. This article demonstrates a modification to SMASH that allows reconstruction of a full set of accelerated individual compone nt coil images by fitting component coil sensitivity functions to a complet e set of spatial harmonics tailored for each coil in the array. Standard co mponent coil combinations applied to the individual reconstructed images pr oduce final composite images free of phase cancellation artifacts. (C) 2001 Wiley-Liss, Inc.