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Adapted random sampling patterns for accelerated MRI

  • Florian KnollEmail author
  • Christian Clason
  • Clemens Diwoky
  • Rudolf Stollberger
Original Article

Abstract

Objective

Variable density random sampling patterns have recently become increasingly popular for accelerated imaging strategies, as they lead to incoherent aliasing artifacts. However, the design of these sampling patterns is still an open problem. Current strategies use model assumptions like polynomials of different order to generate a probability density function that is then used to generate the sampling pattern. This approach relies on the optimization of design parameters which is very time consuming and therefore impractical for daily clinical use.

Materials and methods

This work presents a new approach that generates sampling patterns by making use of power spectra of existing reference data sets and hence requires neither parameter tuning nor an a priori mathematical model of the density of sampling points.

Results

The approach is validated with downsampling experiments, as well as with accelerated in vivo measurements. The proposed approach is compared with established sampling patterns, and the generalization potential is tested by using a range of reference images. Quantitative evaluation is performed for the downsampling experiments using RMS differences to the original, fully sampled data set.

Conclusion

Our results demonstrate that the image quality of the method presented in this paper is comparable to that of an established model-based strategy when optimization of the model parameter is carried out and yields superior results to non-optimized model parameters. However, no random sampling pattern showed superior performance when compared to conventional Cartesian subsampling for the considered reconstruction strategy.

Keywords

Accelerated imaging Parallel imaging Variable density sampling Random sampling 

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Copyright information

© ESMRMB 2010

Authors and Affiliations

  • Florian Knoll
    • 1
    Email author
  • Christian Clason
    • 2
  • Clemens Diwoky
    • 1
  • Rudolf Stollberger
    • 1
  1. 1.Institute of Medical EngineeringGraz University of TechnologyGrazAustria
  2. 2.Institute for Mathematics and Scientific ComputingUniversity of GrazGrazAustria

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