Abstract
Abstract A variable-density k-space sampling method is proposed to
reduce aliasing artifacts in MR images. Because most of the energy
of an image is concentrated around the k-space center, aliasing artifacts
will contain mostly low-frequency components if the k-space is uniformly
undersampled. On the other hand, because the outer k-space region
contains little energy, undersampling that region will not contribute
severe aliasing artifacts. Therefore, a variable-density trajectory
may sufficiently sample the central k-space region to reduce low-frequency
aliasing artifacts and may undersample the outer k-space region to
reduce scan time and to increase resolution. In this paper, the variable-density
sampling method was implemented for both spiral imaging and two-dimensional
Fourier transform (2DFT) imaging. Simulations, phantom images and
in vivo cardiac images show that this method can significantly reduce
the total energy of aliasing artifacts. In general, this method can
be applied to all types of k-space sampling trajectories. Magn Reson
Med 43:452–458, 2000. © 2000 Wiley-Liss, Inc.
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