Chebyshev series for designing RF pulses employing an optimal control approach

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dc.contributor.authorUlloa Allendes, José Luis
dc.contributor.authorGuarini Hermann, Marcelo Walter
dc.contributor.authorGuesalaga Meissner, Andrés
dc.contributor.authorIrarrazaval Barros, Pablo
dc.date.accessioned2022-05-18T14:39:50Z
dc.date.available2022-05-18T14:39:50Z
dc.date.issued2004
dc.description.abstractMagnetic resonance imaging (MRI) provides bidimensional images with high definition and selectivity. Selective excitations are achieved applying a gradient and a radio frequency (RF) pulse simultaneously. They are modeled by the Bloch differential equation, which has no closed-form solution. Most methods for designing RF pulses are derived from approximation of this equation or are based on iterative optimization methods. The approximation methods are only valid for small tip angles and the optimization-based algorithms yield better results, but they are computationally intensive. To improve the solutions and to reduce processing time, a method for designing RF pulses using a pseudospectral approach is presented. The Bloch equation is expanded in Chebyshev series, which can be solved using a sparse linear algebraic system. The method permits three different formulations derived from the optimal control theory, minimum distance, minimum energy, or minimum time, which are solved as algebraic constrained minimization problems. The results were validated through simulated and real experiments of 90/spl deg/ and 180/spl deg/ RF pulses. They show improvements compared to the corresponding solutions obtained using the Shinnar-Le Roux method. The minimum time formulation produces the best performance for 180/spl deg/ pulses, reducing the excitation length in 4% and the RF pulse energy in 3%.
dc.fuente.origenIEEE
dc.identifier.doi10.1109/TMI.2004.835602
dc.identifier.issn1558-254X
dc.identifier.urihttps://doi.org/10.1109/TMI.2004.835602
dc.identifier.urihttps://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1350901
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/64177
dc.information.autorucEscuela de ingeniería ; Ulloa Allendes, José Luis ; S/I ; 9150
dc.information.autorucEscuela de ingeniería ; Guarini Hermann, Marcelo Walter ; S/I ; 99643
dc.information.autorucEscuela de ingeniería ; Guesalaga Meissner, Andrés ; S/I ; 6387
dc.information.autorucEscuela de ingeniería ; Irarrazabal Barros, Pablo ; S/I ; 102769
dc.issue.numero11
dc.language.isoen
dc.nota.accesoContenido parcial
dc.pagina.final1452
dc.pagina.inicio1445
dc.revistaIEEE Transactions on Medical Imaging
dc.rightsacceso restringido
dc.subjectChebyshev approximation
dc.subjectRadio frequency
dc.subjectOptimal control
dc.subjectMagnetic resonance imaging
dc.subjectDesign methodology
dc.subjectOptimization methods
dc.subjectDifferential equations
dc.subjectClosed-form solution
dc.subjectIterative methods
dc.subjectApproximation methods
dc.titleChebyshev series for designing RF pulses employing an optimal control approaches_ES
dc.typeartículo
dc.volumen23
sipa.codpersvinculados9150
sipa.codpersvinculados99643
sipa.codpersvinculados6387
sipa.codpersvinculados102769
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