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Advanced design of MRI inversion pulses for inhomogeneous field conditions by optimal control

Non‐selective inversion pulses find widespread use in MRI applications, where requirements on them are increasingly demanding. With the use of high and ultra‐high field strength systems, robustness to [Formula: see text] and [Formula: see text] inhomogeneities, while tackling SAR and hardware limita...

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Detalles Bibliográficos
Autores principales: Graf, Christina, Soellradl, Martin, Aigner, Christoph Stefan, Rund, Armin, Stollberger, Rudolf
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9786750/
https://www.ncbi.nlm.nih.gov/pubmed/35731240
http://dx.doi.org/10.1002/nbm.4790
Descripción
Sumario:Non‐selective inversion pulses find widespread use in MRI applications, where requirements on them are increasingly demanding. With the use of high and ultra‐high field strength systems, robustness to [Formula: see text] and [Formula: see text] inhomogeneities, while tackling SAR and hardware limitations, has rapidly become important. In this work, we propose a time‐optimal control framework for the optimization of [Formula: see text] ‐ and [Formula: see text] ‐robust inversion pulses. Robustness is addressed by means of ensemble formulations, while allowing inclusion of hardware and energy limitations. The framework is flexible and performs excellently for various optimization goals. The optimization results are analyzed extensively in numerical experiments. Furthermore, they are validated, and compared with adiabatic RF pulses, in various phantom and in vivo measurements on a 3 T MRI system.