JP-2023515262-A5 -

Dates

Publication Date

20230525

Application Date

20210420

Description

This invention relates to the field of magnetic resonance (MR) imaging. The invention relates to a method for MR imaging of at least a portion of a subject . The invention also relates to a computer program executed in an MR apparatus. According to the present invention, a method for obtaining MR images of at least a portion of an object placed within an MR device inspection volume is disclosed. The method is: A step of providing the target portion to a first excitation echo imaging sequence having at least two preparation RF pulses radiated toward the target portion during a first preparation period, and a sequence of read RF pulses radiated toward the target portion during a first acquisition period that temporally follows the first preparation period, The steps include acquiring a first set of FID signals and a first set of excitation echo signals during the first acquisition period, A step of providing the target portion to a second excitation echo imaging sequence having at least two preparation RF pulses radiated toward the target portion during a second preparation period, and a sequence of read RF pulses radiated toward the target portion during a second acquisition period that temporally follows the second preparation period, A step of acquiring a second set of FID signals and a second set of excitation echo signals during the second acquisition period, wherein the first and second sets of FID signals have different T1 weightings, and/or the first and second sets of excitation echo signals have different T1 weightings, The step of deriving a B1 map showing the spatial distribution of the RF field of the RF pulse within the body portion from the first and second sets of acquired FID and excitation echo signals, wherein the different T1 weightings are used to compensate for the effect on the B1 map resulting from T1 relaxation.