Critical sampling in ROSE scanning.

The acquisition of unaliased ROSE (Radially Oriented Sinusoidal Excursions in k-space) data requires the appropriate selection of a gradient frequency, number of interleaves, and number of data samples per acquisition. When the data samples are uniformly distributed in time, they fall on irregularly spaced circles in k-space. Aliasing due to radial undersampling will be eliminated when the number of sample circles equals the number of pixels in one dimension of the desired reconstructed image. Azimuthal aliasing will be completely eliminated when the total number of ROSE petals is four times the number of pixels in one dimension, but acceptable reconstructions may be had with fewer petals. Magn Reson Med 44:129-136, 2000.
(Copyright 2000 Wiley-Liss, Inc.)