Reconstruction strategy for echo planar spectroscopy and its application to partially undersampled imaging

The most commonly encountered form of echo planar spectroscopy involves osc illating gradients in one spatial dimension during readout, Data are conseq uently not sampled on a Cartesian grid. A fast gridding algorithm applicabl e to this particular situation is presented. The method is optimal, i.e., i t performs as well as the full discrete Fourier transform for band limited signals while allowing for use of the fast Fourier transform. The method is demonstrated for reconstruction of data that are partially undersampled in the time domain. The advantages of undersampling are lower hardware requir ements or fewer interleaves per acquisition. The method is of particular in terest when large bandwidths are needed (e.g., for high field scanning) and for scanners with limited gradient performance. The unavoidable artifacts resulting from undersampling are demonstrated to be acceptable for spectros copy with long echo times. (C) 2000 Wiley-Liss, Inc.