US 12,405,325 B2
MR imaging with T1 compensated B1 mapping
Kay Nehrke, Ammersbek (DE); and Peter Boernert, Hamburg (DE)
Assigned to Koninklijke Philips N.V., Eindhoven (NL)
Appl. No. 17/918,582
Filed by KONINKLIJKE PHILIPS N.V., Eindhoven (NL)
PCT Filed Apr. 20, 2021, PCT No. PCT/EP2021/060142
§ 371(c)(1), (2) Date Oct. 13, 2022,
PCT Pub. No. WO2021/214003, PCT Pub. Date Oct. 28, 2021.
Claims priority of application No. 20171014 (EP), filed on Apr. 23, 2020.
Prior Publication US 2023/0145981 A1, May 11, 2023
Int. Cl. G01R 33/24 (2006.01); G01R 33/50 (2006.01); G01R 33/56 (2006.01); G01R 33/561 (2006.01)
CPC G01R 33/246 (2013.01) [G01R 33/50 (2013.01); G01R 33/5602 (2013.01); G01R 33/5617 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of magnetic resonance (MR) imaging of at least a portion of an object placed in an examination volume of an MR device, the method comprising:
subjecting the portion of the object to a first stimulated echo imaging sequence comprising at least two preparation RF pulses (α) radiated toward the portion of the object during a first preparation period and a sequence of reading RF pulses (β) radiated toward the portion of the object during a first acquisition period temporally subsequent to the first preparation period;
acquiring a first set of FID signals (IFID) and a first set of stimulated echo signals (ISTE) during the first acquisition period;
subjecting the portion of the object to a second stimulated echo imaging sequence comprising at least two preparation RF pulses (α) radiated toward the portion of the object during a second preparation period and a sequence of reading RF pulses (β) radiated toward the portion of the object during a second acquisition period temporally subsequent to the second preparation period;
acquiring a second set of FID signals (IFID) and a second set of stimulated echo signals (ISTE) during the second acquisition period, wherein one of the first stimulated echo imaging sequence or the second stimulated echo imaging sequence is preceded by a pre-preparation RF pulse for manipulating a first longitudinal magnetization at a beginning of the first stimulated echo imaging sequence to differ from a second longitudinal magnetization at a beginning of the second stimulated echo imaging sequence; and
deriving a B1 map indicating a spatial distribution of an RF field of the RF pulses within the portion of the object from the first and second sets of FID (IFID) signals and the first and second sets of stimulated echo (ISTE) signals, wherein the pre-preparation RF pulse compensates for influences on the B1 map caused by T1 relaxation.