## Abstract

A new class of spiral trajectories called variable slew-rate spirals is proposed. The governing differential equations for a variable slew-rate spiral are derived, and both numeric and analytic solutions to the equations are given. The primary application of variable slew-rate spirals is peak B_{1} amplitude reduction in 2D RF pulse design. The reduction of peak B_{1} amplitude is achieved by changing the gradient slew-rate profile, and gradient amplitude and slew-rate constraints are inherently satisfied by the design of variable slew-rate spiral gradient waveforms. A design example of 2D RF pulses is given, which shows that under the same hardware constraints the RF pulse using a properly chosen variable slew-rate spiral trajectory can be much shorter than that using a conventional constant slew-rate spiral trajectory, thus having greater immunity to resonance frequency offsets.

Original language | English (US) |
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Pages (from-to) | 835-842 |

Number of pages | 8 |

Journal | Magnetic Resonance in Medicine |

Volume | 58 |

Issue number | 4 |

DOIs | |

State | Published - Oct 2007 |

## Keywords

- RF pulse design
- Slew rate
- Spiral
- VERSE

## ASJC Scopus subject areas

- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology

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