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k ‐ t 2 BLAST: Exploiting spatiotemporal structure in simultaneously cardiac and respiratory time‐resolved volumetric imaging
Author(s) -
Sigfridsson Andreas,
Wigström Lars,
Kvitting JohnPeder Escobar,
Knutsson Hans
Publication year - 2007
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.21295
Subject(s) - temporal resolution , image resolution , k space , computer science , sampling (signal processing) , interpolation (computer graphics) , nonuniform sampling , cardiac imaging , time domain , cardiac cycle , algorithm , physics , artificial intelligence , mathematics , computer vision , fourier transform , medicine , optics , mathematical analysis , filter (signal processing) , motion (physics) , quantization (signal processing) , cardiology
Multidimensional imaging resolving both the cardiac and respiratory cycles simultaneously has the potential to describe important physiological interdependences between the heart and pulmonary processes. A fully five‐dimensional acquisition with three spatial and two temporal dimensions is hampered, however, by the long acquisition time and low spatial resolution. A technique is proposed to reduce the scan time substantially by extending the k ‐ t BLAST framework to two temporal dimensions. By sampling the k ‐ t space sparsely in a lattice grid, the signal in the transform domain, x ‐ f space, can be densely packed, exploiting the fact that large regions in the field of view have low temporal bandwidth. A volumetric online prospective triggering approach with full cardiac and respiratory cycle coverage was implemented. Retrospective temporal interpolation was used to refine the timing estimates for the center of k ‐space, which is sampled for all cardiac and respiratory time frames. This resulted in reduced reconstruction error compared with conventional k ‐ t BLAST reconstruction. The k ‐ t 2 BLAST technique was evaluated by decimating a fully sampled five‐dimensional data set, and feasibility was further demonstrated by performing sparsely sampled acquisitions. Compared to the fully sampled data, a fourfold improvement in spatial resolution was accomplished in approximately half the scan time. Magn Reson Med 58:922–930, 2007. © 2007 Wiley‐Liss, Inc.