Minimisation of slab-selective radiofrequency excitation pulse durations constrained by an acceptable aliasing coefficient

• Published in: Magnetic resonance imaging 2021-09, Vol.81, p.94-100
• Main Authors: Fair, Merlin J., Gatehouse, Peter D., Firmin, David N.
• Format: Article
• Language: English
• Subjects: Minimised duration; RF excitation; Slab-aliasing; Slab-selective
• ISSN: 0730-725X; 1873-5894
• DOI: 10.1016/j.mri.2021.06.019

A technical note is presented on the slab-direction aliasing of 3D imaging, introducing a simple methodology for determining the minimised duration of low flip-angle sinc radiofrequency (RF) excitation pulses, with respect to a required slab profile accuracy. The various interdependent factors affected in modifying an RF pulse duration are considered and analysed in the context of a new metric for quantifying the levels of permitted slab-aliasing. A general framework is presented for the selection of standard sinc RF excitation pulses with system-minimised durations, as well as their analysis and validation, and a demonstration of this methodology is performed for an example requirement and scanner. This methodology enables implementation of standard (vendor-generated) RF pulses with minimised duration for a required application, with high confidence in their operational reliability. Parts of such a methodology may also in theory be extended to more advanced RF pulse designs.