Granted Patent B2

US 12,560,664 · App. 18/244,282 · Granted Feb 24, 2026

Inventors: Ali Aghaeifar (Tübingen, DE); Belinda Ding Yuan (Glasgow, GB); Raphael Tomi-Tricot (London, GB); Iulius Dragonu (Harrow, GB); Radhouene Neji (London, GB)

Assignee: Siemens Healthineers AG

G01R33/543G01R33/246G01R33/3875G01R33/4835G01R33/5659

Abstract

Claims (50)

1 . A method for subject-specific optimization of a radio frequency (RF) pulse for exciting spins in a slab of a number of overlapping slabs in a magnetic resonance examination of a subject including sequential acquisition of the number of overlapping slabs, wherein the RF pulse is to be played out with a coil having a plurality of independent parallel transmit elements, each transmit element of the plurality of independent parallel transmit elements having a different complex B1+ field distribution, the method comprising:

receiving complex B1+ field sensitivity maps for the plurality of independent parallel transmit elements;

dividing the slab into at least two sub-slabs;

for each sub-slab of the at least two sub-slabs, performing B1+ shimming, such that RF shim settings for the plurality of independent parallel transmit elements are optimized; and

combining the optimized RF shim settings for each sub-slab, such that a multiband RF pulse that simultaneously excites the spins in the slab is created,

wherein the at least two sub-slabs are contiguous and do not overlap.

2 . The method of claim 1 , wherein the B1+ shimming is a static B1+ shimming.

3 . The method of claim 2 , wherein the B1+ shimming is a static B1+ shimming using a magnitude-least-squares optimization method.

4 . The method of claim 1 , wherein the slab is divided into two to five sub-slabs in a slice-select direction.

5 . The method of claim 1 , wherein the slab is divided into two to three sub-slabs in a slice-select direction.

6 . The method of claim 1 , wherein combining the optimized RF shim settings comprises:

calculating an individual RF pulse for each sub-slab of the at least two sub-slabs using the optimized RF shim setting; and

summing the individual RF pulses, such that a multiband RF pulse that simultaneously excites the spins in a complete slab is created.

7 . The method of claim 6 , further comprising multiplying the multiband RF pulse with a ramp profile in the frequency domain, such that a tilted optimized non-saturating excitation (TONE) multiband parallel transmission RF pulse is created after the optimized RF shim settings are combined.

8 . A method for acquiring magnetic resonance data from a subject using a coil having a plurality of independent parallel transmit elements, each transmit element of the plurality of independent parallel transmit elements having a different complex B1+ field distribution, the method comprising:

generating a magnetic resonance acquisition sequence comprising at least one radio frequency (RF) pulse that has been optimized, the at least one RF pulse being for exciting spins in a slab of a number of overlapping slabs, wherein the magnetic resonance acquisition sequence involves a sequential acquisition of the number of overlapping slabs,

wherein the optimization of the at least one RF pulse comprises:

receipt of complex B1+ field sensitivity maps for the plurality of independent parallel transmit elements;

division of the slab into at least two sub-slabs;

for each sub-slab of the at least two sub-slabs, performance of B1+ shimming, such that RF shim settings for the plurality of independent parallel transmit elements are optimized; and

combination of the optimized RF shim settings for each sub-slab, such that a multiband RF pulse that simultaneously excites the spins in the slab is created,

wherein the at least two sub-slabs are contiguous and do not overlap.

9 . The method of claim 8 , wherein the slab has a thickness of 10 mm to 100 mm in a slice-select direction.

10 . The method of claim 9 , wherein the slab has a thickness of 15 mm to 60 mm in the slice-select direction.

11 . The method of claim 9 , wherein the slab has a thickness of 20 mm to 50 mm in the slice-select direction.

12 . The method of claim 8 , wherein the magnetic resonance acquisition sequence is a three-dimensional imaging sequence.

13 . The method of claim 8 , wherein the magnetic resonance acquisition sequence is a time-of-flight angiography sequence.

14 . In a non-transient computer-readable storage medium that stores instructions executable by a control unit of a magnetic resonance imaging system for subject-specific optimization of a radio frequency (RF) pulse for exciting spins in a slab of a number of overlapping slabs in a magnetic resonance examination of a subject including sequential acquisition of the number of overlapping slabs, wherein the RF pulse is to be played out with a coil having a plurality of independent parallel transmit elements, each transmit element of the plurality of independent parallel transmit elements having a different complex B1+ field distribution, the instructions comprising:

receiving complex B1+ field sensitivity maps for the plurality of independent parallel transmit elements;

dividing the slab into at least two sub-slabs;

for each sub-slab of the at least two sub-slabs, performing B1+ shimming, such that RF shim settings for the plurality of independent parallel transmit elements are optimized; and

combining the optimized RF shim settings for each sub-slab, such that a multiband RF pulse that simultaneously excites the spins in the slab is created,

wherein the at least two sub-slabs are contiguous and do not overlap.

15 . A control unit for a magnetic resonance imaging system, the control unit comprising:

a processor configured to:

subject-specific optimize a radio frequency (RF) pulse for exciting spins in a slab of a number of overlapping slabs in a magnetic resonance examination of a subject including sequential acquisition of the number of overlapping slabs, wherein the RF pulse is to be played out with a coil having a plurality of independent parallel transmit elements, each transmit element of the plurality of independent parallel transmit elements having a different complex B1+ field distribution, the subject-specific optimization comprising:

receipt of complex B1+ field sensitivity maps for the plurality of independent parallel transmit elements;

division of the slab into at least two sub-slabs;

for each sub-slab of the at least two sub-slabs, performance of B1+ shimming, such that RF shim settings for the plurality of independent parallel transmit elements are optimized; and

combination of the optimized RF shim settings for each sub-slab, such that a multiband RF pulse that simultaneously excites the spins in the slab is created,

wherein the at least two sub-slabs are contiguous and do not overlap.

16 . A magnetic resonance imaging system comprising:

a control unit comprising:

a processor configured to:

subject-specific optimize a radio frequency (RF) pulse for exciting spins in a slab of a number of overlapping slabs in a magnetic resonance examination of a subject including sequential acquisition of the number of overlapping slabs, wherein the RF pulse is to be played out with a coil having a plurality of independent parallel transmit elements, each transmit element of the plurality of independent parallel transmit elements having a different complex B1+ field distribution, the subject-specific optimization comprising:

receipt of complex B1+ field sensitivity maps for the plurality of independent parallel transmit elements;

division of the slab into at least two sub-slabs;

for each sub-slab of the at least two sub-slabs, performance of B1+ shimming, such that RF shim settings for the plurality of independent parallel transmit elements are optimized; and

combination of the optimized RF shim settings for each sub-slab, such that a multiband RF pulse that simultaneously excites the spins in the slab is created,

wherein the at least two sub-slabs are contiguous and do not overlap.

Assignments (3)

Priority Claims (1)

Continuity (1)

References Cited (14)