Optimal control theory for applications in Magnetic Resonance Imaging

Reeth, Eric van; Ratiney, H.; Lapert, M.; Glaser, Steffen J.; Sugny, Dominique

doi:10.1186/s40736-017-0034-3

Cited by 12 publications

(12 citation statements)

References 56 publications

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“…More recently, the application of optimized RF pulses, designed with an Optimal Control (OC) algorithm, in presence of a constant gradient was investigated 27 , 28 . OC theory was demonstrated to be useful in MRI in the context of image contrast optimization 29 , 30 and robust excitation and refocusing 31 – 33 . Both mentioned applications are based on the NMR signal magnitude whereas in the case of MRE, OC pulses were proposed for phase contrast applications such as MRE 28 .…”

Section: Introductionmentioning

confidence: 99%

Short echo time dual-frequency MR Elastography with Optimal Control RF pulses

Sango-Solanas

Koon

Reeth

et al. 2022

Sci Rep

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Magnetic Resonance Elastography (MRE) quantifies the mechanical properties of tissues, typically applying motion encoding gradients (MEG). Multifrequency results allow better characterizations of tissues using data usually acquired through sequential monofrequency experiments. High frequencies are difficult to reach due to slew rate limitations and low frequencies induce long TEs, yielding magnitude images with low SNR. We propose a novel strategy to perform simultaneous multifrequency MRE in the absence of MEGs: using RF pulses designed via the Optimal Control (OC) theory. Such pulses control the spatial distribution of the MRI magnetization phase so that the resulting transverse magnetization reproduces the phase pattern of an MRE acquisition. The pulse is applied with a constant gradient during the multifrequency mechanical excitation to simultaneously achieve slice selection and motion encoding. The phase offset sampling strategy can be adapted according to the excitation frequencies to reduce the acquisition time. Phantom experiments were run to compare the classical monofrequency MRE to the OC based dual-frequency MRE method and showed excellent agreement between the reconstructed shear storage modulus G′. Our method could be applied to simultaneously acquire low and high frequency components, which are difficult to encode with the classical MEG MRE strategy.

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Section: Introductionmentioning

confidence: 99%

Short echo time dual-frequency MR Elastography with Optimal Control RF pulses

Sango-Solanas

Koon

Reeth

et al. 2022

Sci Rep

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“…In this context, our approach is to investigate the possibilities of enhancing contrast by modeling an arbitrary preparation inside the MP-RAGE. Our work is based on the recent optimal control framework proposed for the design of a preparation to optimize MRI contrast based on the relaxations differences [5][6][7]. This paper presents a novel use of the GRAPE algorithm in order to optimize a complex preparation within the establishment of a longitudinal steady state.…”

Section: Introductionmentioning

confidence: 99%

MRI Contrast Enhancement of Magnetization Prepared Steady State Sequence: An Optimal Control Framework

Vernier

Reeth

Pilleul

et al. 2021

2021 IEEE 18th International Symposium on Biomedical Imaging (ISBI)

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The present work investigates the possibilities of enhancing MRI contrast between two target tissues in a threedimensional Magnetization-Prepared Rapid Gradient-Echo (MP-RAGE) based on relaxation time's differences. The benefit lies in the adaptation of the GRAPE algorithm to the optimization of a magnetization preparation in a cyclic sequence without full recovery between each cycle. This numerical approach allows optimizing a magnetization preparation of an arbitrary number of radio frequency pulses to enhance contrast, taking in account the establishment of a steady state in the longitudinal component of the magnetization. In vivo validation on rat brain is performed at 11.7T and shows the benefit of an optimized T2Prep-IR compared to a simple inversion to enhance contrast between white and gray matter.

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“…Several optimization algorithms [8][9][10][11] have been proposed to design control fields suited to different experimental setups and constraints or robust against experimental uncertainties and modelling imperfections [12][13][14][15][16][17][18][19][20]. QOCT has been first developed in molecular physics to steer chemical reactions [2,6,21,22] and in Nuclear Magnetic Resonance (NMR) or Magnetic Resonance Imaging for controlling spin dynamics [8,[23][24][25][26][27][28][29][30]. OCT is nowadays attracting a lof of effort in the context of quantum information processing [31][32][33][34] and has been recognized as one of the cornerstones for enabling quantum technologies [1].…”

Section: Introductionmentioning

confidence: 99%

Optimal control of an inhomogeneous spin ensemble coupled to a cavity

et al. 2018

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We apply optimal control techniques to an inhomogeneous spin ensemble coupled to a cavity. A general procedure is proposed for designing the control strategies. We numerically show the extent to which optimal control fields robust against system uncertainties help enhancing the sensitivity of the detection process. The parameters of the numerical simulations are taken from recent Electron Spin Resonance experiments. The low and high cooperativity regimes are explored.

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Optimal control theory for applications in Magnetic Resonance Imaging

Cited by 12 publications

References 56 publications

Short echo time dual-frequency MR Elastography with Optimal Control RF pulses

Short echo time dual-frequency MR Elastography with Optimal Control RF pulses

MRI Contrast Enhancement of Magnetization Prepared Steady State Sequence: An Optimal Control Framework

Optimal control of an inhomogeneous spin ensemble coupled to a cavity

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