title: Sparsity-enforced slice-selective MRI RF excitation pulse design.
abstract: We introduce a novel algorithm for the design of fast slice-selective spatially-tailored magnetic resonance imaging (MRI) excitation pulses. This method, based on sparse approximation theory, uses a second-order cone optimization to place and modulate a small number of slice-selective sinc-like radio-frequency (RF) pulse segments ("spokes") in excitation k-space, enforcing sparsity on the number of spokes allowed while simultaneously encouraging those that remain to be placed and modulated in a way that best forms a user-defined in-plane target magnetization. Pulses are designed to mitigate B(1) inhomogeneity in a water phantom at 7 T and to produce highly-structured excitations in an oil phantom on an eight-channel parallel excitation system at 3 T. In each experiment, pulses generated by the sparsity-enforced method outperform those created via conventional Fourier-based techniques, e.g., when attempting to produce a uniform magnetization in the presence of severe B(1) inhomogeneity, a 5.7-ms 15-spoke pulse generated by the sparsity-enforced method produces an excitation with 1.28 times lower root mean square error than conventionally-designed 15-spoke pulses. To achieve this same level of uniformity, the conventional methods need to use 29-spoke pulses that are 7.8 ms long.
authors.affiliation: Research Laboratory of Electronics, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA zelinski@MIT.edu
authors.forename: Adam C
authors.initials: AC
authors.lastname: Zelinski
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Wald
authors.forename: Kawin
authors.initials: K
authors.lastname: Setsompop
authors.forename: Vivek K
authors.initials: VK
authors.lastname: Goyal
authors.forename: Elfar
authors.initials: E
authors.lastname: Adalsteinsson
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012815:Signal Processing, Computer-Assisted
references.citation: Magn Reson Med. 1998 Dec;40(6):847-56
references.pmid: 9840829
references.citation: Magn Reson Med. 1994 Jun;31(6):691-4
references.pmid: 8057824
references.citation: Magn Reson Med. 1997 Oct;38(4):591-603
references.pmid: 9324327
references.citation: Magn Reson Med. 2006 Apr;55(4):719-24
references.pmid: 16526012
references.citation: Magn Reson Med. 2001 Jul;46(1):24-30
references.pmid: 11443707
references.citation: Magn Reson Med. 1999 Nov;42(5):952-62
references.pmid: 10542355
references.citation: Radiology. 1986 Dec;161(3):717-20
references.pmid: 3786721
references.citation: Magn Reson Med. 2006 Nov;56(5):1163-71
references.pmid: 17036289
references.citation: Magn Reson Med. 2007 Sep;58(3):598-604
references.pmid: 17763362
references.citation: Magn Reson Med. 2006 Nov;56(5):1050-9
references.pmid: 17041911
references.citation: Phys Med Biol. 2001 Feb;46(2):609-19
references.pmid: 11229737
references.citation: Magn Reson Med. 2005 Feb;53(2):408-17
references.pmid: 15678526
references.citation: Magn Reson Med. 2006 Sep;56(3):620-9
references.pmid: 16894579
references.citation: Magn Reson Med. 2005 Oct;54(4):908-17
references.pmid: 16155881
references.citation: J Magn Reson. 2011 Dec;213(2):544-57
references.pmid: 22152370
references.citation: J Magn Reson Imaging. 2005 Feb;21(2):192-6
references.pmid: 15666397
references.citation: Magn Reson Med. 2003 Jan;49(1):144-50
references.pmid: 12509830
references.citation: NMR Biomed. 1988 Jun;1(3):151-8
references.pmid: 3275125
references.citation: Phys Med Biol. 1978 Jul;23(4):630-43
references.pmid: 704667
references.citation: Magn Reson Med. 2000 Feb;43(2):284-9
references.pmid: 10680693
references.citation: IEEE Trans Med Imaging. 2004 Apr;23(4):520-5
references.pmid: 15084077
references.citation: Magn Reson Med. 1997 Dec;38(6):953-63
references.pmid: 9402197
references.citation: Magn Reson Med. 2005 Oct;54(4):994-1001
references.pmid: 16155886
references.citation: Magn Reson Med. 2004 Apr;51(4):775-84
references.pmid: 15065251
references.citation: Magn Reson Med. 2005 Dec;54(6):1503-18
references.pmid: 16270333