Reconstructing MR images from undersampled data: Data-weighting considerations

Data which are sampled more densely than the Nyquist limit in k-space are w eighted prior to reconstruction by the inverse of the local sampling densit y. This work considers the effects of weighting data that are sampled less densely than the Nyquist limit. It specifically analyzes azimuthally unders ampled projection reconstruction, variable density spirals, and variable de nsity phase encoding. Effects on resolution, aliasing, and SNR are given. H igher resolution is obtained by weighting under-sampled data according to t he inverse of sampling density, while better SNR and less aliasing artifact are obtained by weighting undersampled data uniformly. Magn Reson Med 43:8 67-875, 2000. (C) 2000 Wiley-Liss, Inc.