Mr imaging with t1 compensated b1 mapping

Abstract

The invention relates to a method of MR imaging. It is an object of the invention to provide an improved Bmapping method that is less affected by Trelaxation. The invention proposes that a first stimulated echo imaging sequence () is generated comprising at least two preparation RF pulses (α) radiated during a first preparation period () and a sequence of reading RF pulses (β) radiated during a first acquisition period () temporally subsequent to the first preparation period (). A first set of FID signals (I) and a first set of stimulated echo signals (I) are acquired during the first acquisition period (). A second stimulated echo imaging sequence () is generated comprising again at least two preparation RF pulses (α) radiated during a second preparation period () and a sequence of reading RF pulses (β) radiated during a second acquisition period () temporally subsequent to the second preparation period (). A second set of FID signals (I) and a second set of stimulated echo signals (I) are acquired during the second acquisition period (). The first and second sets of FID signals (IFID) have different T-weightings and/or the first and second sets of stimulated echo signals (I) have different T-weightings. A Bmap indicating the spatial distribution of the RF field of the RF pulses is derived from the acquired first and second sets of FID (I) and stimulated echo (I) signals, wherein the different T-weightings are made use of to compensate for influences on the Bmap caused by Trelaxation. Preferably, either the first or the second preparation period () is preceded by an RF inversion pulse to obtain the different T-weightings. Moreover, the invention relates to an MR device () and to a computer program for an MR device ().