Time optimal control-based RF pulse design under gradient imperfections

Christoph S Aigner, Armin Rund, Samy Abo Seada, Anthony N Price, Joseph V Hajnal, Shaihan J Malik, Karl Kunisch, Rudolf Stollberger

Publikation: Beitrag in einer FachzeitschriftArtikelForschungBegutachtung

Abstract

PURPOSE: This study incorporates a gradient system imperfection model into an optimal control framework for radio frequency (RF) pulse design.

THEORY AND METHODS: The joint design of minimum-time RF and slice selective gradient shapes is posed as an optimal control problem. Hardware limitations such as maximal amplitudes for RF and slice selective gradient or its slew rate are included as hard constraints to assure practical applicability of the optimized waveforms. In order to guarantee the performance of the optimized waveform with possible gradient system disturbances such as limited system bandwidth and eddy currents, a measured gradient impulse response function (GIRF) for a specific system is integrated into the optimization.

RESULTS: The method generates optimized RF and pre-distorted slice selective gradient shapes for refocusing that are able to fully compensate the modeled imperfections of the gradient system under investigation. The results nearly regenerate the optimal results of an idealized gradient system. The numerical Bloch simulations are validated by phantom and in-vivo experiments on 2 3T scanners.

CONCLUSIONS: The presented design approach demonstrates the successful correction of gradient system imperfections within an optimal control framework for RF pulse design.

Originalspracheenglisch
Seiten (von - bis)561-574
Seitenumfang14
FachzeitschriftMagnetic Resonance in Medicine
Jahrgang83
Ausgabenummer2
DOIs
PublikationsstatusVeröffentlicht - Feb 2020

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Time optimal control-based RF pulse design under gradient imperfections. / Aigner, Christoph S; Rund, Armin; Abo Seada, Samy; Price, Anthony N; Hajnal, Joseph V; Malik, Shaihan J; Kunisch, Karl; Stollberger, Rudolf.

in: Magnetic Resonance in Medicine, Jahrgang 83, Nr. 2, 02.2020, S. 561-574.

Publikation: Beitrag in einer FachzeitschriftArtikelForschungBegutachtung

Aigner, Christoph S ; Rund, Armin ; Abo Seada, Samy ; Price, Anthony N ; Hajnal, Joseph V ; Malik, Shaihan J ; Kunisch, Karl ; Stollberger, Rudolf. / Time optimal control-based RF pulse design under gradient imperfections. in: Magnetic Resonance in Medicine. 2020 ; Jahrgang 83, Nr. 2. S. 561-574.
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title = "Time optimal control-based RF pulse design under gradient imperfections",
abstract = "PURPOSE: This study incorporates a gradient system imperfection model into an optimal control framework for radio frequency (RF) pulse design.THEORY AND METHODS: The joint design of minimum-time RF and slice selective gradient shapes is posed as an optimal control problem. Hardware limitations such as maximal amplitudes for RF and slice selective gradient or its slew rate are included as hard constraints to assure practical applicability of the optimized waveforms. In order to guarantee the performance of the optimized waveform with possible gradient system disturbances such as limited system bandwidth and eddy currents, a measured gradient impulse response function (GIRF) for a specific system is integrated into the optimization.RESULTS: The method generates optimized RF and pre-distorted slice selective gradient shapes for refocusing that are able to fully compensate the modeled imperfections of the gradient system under investigation. The results nearly regenerate the optimal results of an idealized gradient system. The numerical Bloch simulations are validated by phantom and in-vivo experiments on 2 3T scanners.CONCLUSIONS: The presented design approach demonstrates the successful correction of gradient system imperfections within an optimal control framework for RF pulse design.",
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AU - Aigner, Christoph S

AU - Rund, Armin

AU - Abo Seada, Samy

AU - Price, Anthony N

AU - Hajnal, Joseph V

AU - Malik, Shaihan J

AU - Kunisch, Karl

AU - Stollberger, Rudolf

N1 - © 2019 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

PY - 2020/2

Y1 - 2020/2

N2 - PURPOSE: This study incorporates a gradient system imperfection model into an optimal control framework for radio frequency (RF) pulse design.THEORY AND METHODS: The joint design of minimum-time RF and slice selective gradient shapes is posed as an optimal control problem. Hardware limitations such as maximal amplitudes for RF and slice selective gradient or its slew rate are included as hard constraints to assure practical applicability of the optimized waveforms. In order to guarantee the performance of the optimized waveform with possible gradient system disturbances such as limited system bandwidth and eddy currents, a measured gradient impulse response function (GIRF) for a specific system is integrated into the optimization.RESULTS: The method generates optimized RF and pre-distorted slice selective gradient shapes for refocusing that are able to fully compensate the modeled imperfections of the gradient system under investigation. The results nearly regenerate the optimal results of an idealized gradient system. The numerical Bloch simulations are validated by phantom and in-vivo experiments on 2 3T scanners.CONCLUSIONS: The presented design approach demonstrates the successful correction of gradient system imperfections within an optimal control framework for RF pulse design.

AB - PURPOSE: This study incorporates a gradient system imperfection model into an optimal control framework for radio frequency (RF) pulse design.THEORY AND METHODS: The joint design of minimum-time RF and slice selective gradient shapes is posed as an optimal control problem. Hardware limitations such as maximal amplitudes for RF and slice selective gradient or its slew rate are included as hard constraints to assure practical applicability of the optimized waveforms. In order to guarantee the performance of the optimized waveform with possible gradient system disturbances such as limited system bandwidth and eddy currents, a measured gradient impulse response function (GIRF) for a specific system is integrated into the optimization.RESULTS: The method generates optimized RF and pre-distorted slice selective gradient shapes for refocusing that are able to fully compensate the modeled imperfections of the gradient system under investigation. The results nearly regenerate the optimal results of an idealized gradient system. The numerical Bloch simulations are validated by phantom and in-vivo experiments on 2 3T scanners.CONCLUSIONS: The presented design approach demonstrates the successful correction of gradient system imperfections within an optimal control framework for RF pulse design.

U2 - 10.1002/mrm.27955

DO - 10.1002/mrm.27955

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JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

SN - 0740-3194

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