Simultaneous multi-slice magnetic resonance imaging (MRI) has attracted much research interests recently due to its advantages in increasing signal-to-noise ratio (SNR) and decreasing acquisition time. To achieve simultaneous multi-slice excitation, the existing methods used a composite excitation pulse, yielded from the linear combination of radio frequency (RF) pulses with the same amplitude but different phases. The performance of such composite pulse, however, is limited, due to the square relationship between the peak pulse power and slice number. To solve this problem, we proposed a numerical optimization method for multi-slice excitation RF pulse based on both spin dynamics and optimal control theory. Together with slice selection gradient, the optimized pulse achieved selective excitation with arbitrary thickness, distance and number of slices. The performance of the optimized pulse in simultaneous multi-slice MRI was validated by simulation on multimodal imaging-based detailed anatomical (MIDA) digital phantom.
LU Shan
,
CHANG Yan
,
QIAN Song-song
,
SHI Bo
,
YANG Xiao-dong
. Optimization of Selective Radio Frequency Pulses for Simultaneous Multi-Slice MRI[J]. Chinese Journal of Magnetic Resonance, 2018
, 35(2)
: 141
-149
.
DOI: 10.11938/cjmr20172596
[1] 赵喜平. 磁共振成像系统的原理及其应用[M]. 北京:科学出版社, 2000.
[2] WANG X H, SUN P, ZHANG X, et al. Application of magnetic resonance technique to quality and safety evaluation of food[J]. Chinese J Magn Reson, 2017, 34(2):245-256. 王小花, 孙鹏, 张许, 等. 磁共振技术在食品质量与安全研究中的应用[J]. 波谱学杂志, 2017, 34(2):245-256.
[3] MOELLER S, YACOUB E, OLMAN C A, et al. Multiband Multislice GE-EPI at 7 tesla, with 16-fold acceleration using partial parallel imaging with application to high spatial and temporal whole-brain FMRI[J]. Magn Reson Med, 2010, 63(5):1144-1153.
[4] SOUZA S P, SZUMOWSKI J, DUMOULIN C L, et al. SIMA:simultaneous multislice acquisition of MR images by Hadamard-encoded excitation[J]. J Comput Assist Tomo, 1988, 12(6):1026-1030.
[5] GLOVER G H. Phase-offset multiplanar (POMP) volume imaging:a new technique[J]. J Magn Reson Imaging, 1991, 1(4):457-461.
[6] LARKMAN D J, HAJNAL J V, HERLIHY A H, et al. Use of multicoil arrays for separation of signal from multiple slices simultaneously excited[J]. J Magn Reson Imaging, 2001, 13(2):313-317.
[7] LEE K J, WILD J M, GRIFFITHS P D, et al. Simultaneous multislice imaging with slice-multiplexed RF pulses[J]. Magn Reson Med, 2005, 54(4):755-760.
[8] KHANEJA N, REISS T, KEHLET C, et al. Optimal control of coupled spin dynamics:design of NMR pulse sequences by gradient asce nt algorithms[J]. J Magn Reson, 2005, 172(2):296-305.
[9] SKINNER T E, GERSHENZON N I. Optimal control design of pulse shapes as analytic functions[J]. J Magn Reson, 2010, 204(2):248-255.
[10] MASSIRE A, CLOOS M A, VIGNAUD A, et al. Design of non-selective refocusing pulses with phase-free rotation axis by gradient ascent pulse engineering algorithm in parallel transmission at 7 T[J]. J Magn Reson, 2013, 230:76-83.
[11] ZHANG S L, CHANG Y, YANG X D. Optimization of limited amplitude radiofrequency pulse with variance evaluation[J]. Chinese J Magn Reson. 2015, 32(3):462-469. 张树林, 常严, 杨晓冬. 方差评估在幅值限制脉冲优化中的应用[J]. 波谱学杂志, 2015, 32(3):462-469.
[12] VINDING M S, MAXIMOV I I, TOSNER Z, et al. Fast numerical design of spatial-selective rf pulses in MRI using Krotov and quasi-Newton based optimal control methods[J]. J Chem Phys, 2012, 137(5):054203.
[13] KHANEJA N, BROCKETT R, GLASER S. Time optimal control in spin systems[J]. Phys Rev A, 2000, 63(3):222-224.
[14] ERNST R R, BODENHAUSEN G, WOKAUN A, et al. Principles of nuclear magnetic resonance in one and two dimensions[M]. Oxford:Clarendon Press, 1987.
[15] IACONO M I, NEUFELD E, AKINNAGBE E, et al. MIDA:A multimodal imaging-based detailed anatomical model of the human head and neck[J]. Plos One, 2015, 10(4):e0124126.
[16] STAB D, RITTER C O, BREUER F A, et al. CAIPIRINHA accelerated SSFP imaging[J]. Magn Reson Med, 2011, 65(1):157-64.
[17] STOYAN J S. Variable rate selective excitation RF pulse in MRI[D]. Hamilton:McMaster University, 2004.
