BURST excitation pulses

✍ Scribed by Oliver Heid

• Book ID: 102531839
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 448 KB
• Volume: 38
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910380413

✦ Synopsis

Abstract

A theory of optimum burst excitation is developed in the frame‐work of the Shinnar‐LeRoux spinor formalism. An N pulse RF train of constant or linear phase cannot improve on an average echo strength of M~0~/N, and a phase modulation of the pulse train is necessary to improve the signal yield to the theoretical maximum value M~0~√;N. Several methods are presented yielding pulse trains of nearly optimum average amplitude for arbitrary N. It is shown that RF phase spoiling can be analyzed with the same framework. The presented pulse trains may also be useful when ultrawide spectrum hard pulses are required, but only limited RF power is available, e.g., for NMR experiments in extremely inhomogeneous B~0~ fields.