MR IMAGING WITH B1 MAPPING

摘要

The invention relates to a method of MR imaging, wherein a portion of a body placed in the examination volume of an MR device is subjected to an imaging sequence of RF pulses and switched magnetic field gradients. The imaging sequence is a stimulated echo sequence including i) two preparation RF pulses (α) radiated toward the portion of the body during a preparation period (21), and ii) reading RF pulses (β) radiated toward the portion of the body during an acquisition period (22) temporally subsequent to the preparation period (21). FID signals (I1) and stimulated echo signals I2) are acquired during the acquisition period (22) with equal T2*-weighting. A B1 map indicating the spatial distribution of the RF field of the preparation RF pulses within the portion of the body is derived from the acquired FID (I1) and stimulated echo (I2) signals.

主权项

1. Method of MR imaging of at least a portion of a body placed in the examination volume of a MR device, the method comprising the steps of:
subjecting the portion of the body to an imaging sequence of RF pulses and switched magnetic field gradients, which imaging sequence is a stimulated echo sequence including: i) at least two preparation RF pulses (α) radiated toward the portion of the body during a preparation period, and ii) one or more reading RF pulses (β) radiated toward the portion of the body during an acquisition period temporally subsequent to the preparation period; acquiring one or more FID signals (I1) and one or more stimulated echo signals (I2) during the acquisition period; the preparation and reading RF pulses have a sequence timing that causes equal T2* weighting of the one or more FID signals (I1) and the stimulated echo signals and one or more stimulated echo signals (I2) during the acquisition period; deriving a B1 map indicating the spatial distribution of the RF field of the RF pulses within the portion of the body (10) from the acquired FID (I1) and stimulated echo (I2) signals.