Analysis of B1 mapping by Bloch Siegert shift

Abstract

The Bloch-Siegert shift is a new phase-based B1 mapping method [1]. This method utilizes the fact that for a large off-resonance frequency, square of the B1 field magnitude is proportional to the phase. In this study, relation between the off-resonance frequency, the RF pulse shape, and the duration of the RF pulse is investigated. Moreover, importance of the crusher usage in the sequence is examined for the Fermi and hard pulse shapes. Understanding of these parameters can be helpful for the general use of this method and may give an intuition for appropriate RF pulse design.