Fast measurement of B1+ using the NO2RAGE pulse sequence

Abstract

The knowledge of the spatial distribution of the transmit field of the coil, B1+, is essential in a number of MRI applications, particularly at higher field strength. SA2RAGE is a recently developed technique for B1+ mapping, derived from the MP2RAGE scheme. The sensitivity to B1+ is obtained from a preparation pulse and optimized delays between block gradient acquisitions. Here, we propose a much faster (but otherwise comparable) method, referred to as NO2RAGE, where the B1+ sensitivity is obtained by omitting the preparation, nullifying the delays, and adjusting the other sequence parameters. The technique compares favorably against other in vivo methods