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Variable density randomized stack of spirals (VDR‐SoS) for compressive sensing MRI
Author(s) -
Valvano Giuseppe,
Martini Nicola,
Landini Luigi,
Santarelli Maria Filomena
Publication year - 2016
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25847
Subject(s) - undersampling , compressed sensing , imaging phantom , computer science , sampling (signal processing) , coherence (philosophical gambling strategy) , spiral (railway) , acceleration , variable (mathematics) , algorithm , pattern recognition (psychology) , artificial intelligence , mathematics , computer vision , physics , statistics , optics , mathematical analysis , filter (signal processing) , classical mechanics
Purpose To develop a 3D sampling strategy based on a stack of variable density spirals for compressive sensing MRI. Methods A random sampling pattern was obtained by rotating each spiral by a random angle and by delaying for few time steps the gradient waveforms of the different interleaves. A three‐dimensional (3D) variable sampling density was obtained by designing different variable density spirals for each slice encoding. The proposed approach was tested with phantom simulations up to a five‐fold undersampling factor. Fully sampled 3D dataset of a human knee, and of a human brain, were obtained from a healthy volunteer. The proposed approach was tested with off‐line reconstructions of the knee dataset up to a four‐fold acceleration and compared with other noncoherent trajectories. Results The proposed approach outperformed the standard stack of spirals for various undersampling factors. The level of coherence and the reconstruction quality of the proposed approach were similar to those of other trajectories that, however, require 3D gridding for the reconstruction. Conclusion The variable density randomized stack of spirals (VDR‐SoS) is an easily implementable trajectory that could represent a valid sampling strategy for 3D compressive sensing MRI. It guarantees low levels of coherence without requiring 3D gridding. Magn Reson Med 76:59–69, 2016. © 2015 Wiley Periodicals, Inc.