US 12,461,178 B2
Method for subject-specific optimization of a multi-band RF pulse
Belinda Ding Yuan, Glasgow (GB); Iulius Dragonu, Harrow (GB); Raphael Tomi-Tricot, London (GB); Ali Aghaeifar, Tübingen (DE); and Radhouene Neji, London (GB)
Assigned to Siemens Healthineers AG, Forchheim (DE)
Filed by Siemens Healthcare GmbH, Erlangen (DE)
Filed on Aug. 12, 2023, as Appl. No. 18/233,318.
Claims priority of application No. 22190186 (EP), filed on Aug. 12, 2022.
Prior Publication US 2024/0053420 A1, Feb. 15, 2024
Int. Cl. G01R 33/54 (2006.01); A61B 5/00 (2006.01); A61B 5/055 (2006.01); G01R 33/48 (2006.01)
CPC G01R 33/543 (2013.01) [A61B 5/055 (2013.01); A61B 5/7257 (2013.01); G01R 33/4822 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for subject-specific optimization of an RF pulse for exciting spins within a field-of-view to obtain a target magnetization in a magnetic resonance imaging examination of a subject, the RF pulse being a multi-band RF pulse, wherein the RF pulse is a spokes RF pulse comprising a train of sub-pulses interleaved with gradient blips, wherein the gradient blips are configured to determine a trajectory of a magnetization in transmit k-space so that each sub-pulse is played at a specific position in transmit k-space, and wherein each sub-pulse is configured to excite a predetermined number of slices simultaneously, the method comprising:
receiving a starting k-space position and using the starting k-space position as a current k-space position;
for each of the slices to be excited by the RF pulse, performing:
calculating a sub-pulse based on the current k-space position and calculating an expected magnetization after that sub-pulse;
calculating an inverse Fourier transform of a difference between the expected magnetization and the target magnetization;
determining an optimal k-space position for a next spoke for the respective slice to be at a position where an absolute value of the inverse Fourier transform has a maximum;
determining a next k-space position for all slices together based on the optimal k-space positions determined for each slice individually; and
calculating a multi-band RF pulse based on the determined k-space positions.