title: Additive angle method for fast large-tip-angle RF pulse design in parallel excitation.
abstract: Current methods for parallel excitation RF pulse design are based on the small-tip-angle approximation, which provides a computationally efficient means of pulse calculation. In general, pulses designed with those methods are inaccurate when scaled to produce large-tip angles, and methods for large-tip-angle pulse design are more computationally demanding. This paper introduces a fast iterative method for large-tip-angle parallel pulse design that is formulated as a small number of Bloch equation simulations and fast small-tip-angle pulse designs, the results of which add to produce large-tip-angle pulses. Simulations and a phantom experiment demonstrate that the method is effective in designing multidimensional large-tip-angle pulses of high excitation accuracy, compared to pulses designed with small-tip-angle methods.
authors.affiliation: Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA. wgrissom@umich.edu
authors.forename: William A
authors.initials: WA
authors.lastname: Grissom
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Yip
authors.forename: Steven M
authors.initials: SM
authors.lastname: Wright
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Fessler
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Noll
mesh_terms: D000465:Algorithms; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D011846:Radio Waves; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014159:Transducers