Method for the reduction of interference signals

Patent metadata

Field	Value
Publication number	US-12029544-B2
Application number	US-202217708111-A
Country	US
Kind code	B2
Filing date	Mar 30, 2022
Priority date	Mar 31, 2021
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

The disclosure relates to techniques for acquiring measured data that has been recorded simultaneously via a magnetic resonance facility from at least two slices from an examination object comprising at least two different spin types. The techniques includes selecting a desired simultaneous recording of measured data from at least two slices in which during recording phases that generate field of view shifts have been imprinted, selecting a compensation factor to compensate for interference signals caused by the different spin types, determining a compensation phase for the phases to be imprinted in the desired recording as a function of the compensation factor, and carrying out the desired recording of measured data and/or reconstruction of image data from the measured data by applying the compensation phase that has been determined to the respective phases to be imprinted.

First claim

What is claimed is:

1. A method for acquiring measured data that has been recorded simultaneously, via a magnetic resonance apparatus, from at least two slices identified with an examination object comprising at least two different spin types, comprising:
selecting, via the magnetic resonance apparatus, a simultaneous recording of measured data from the at least two slices in which phases that generate field of view shifts are to be imprinted during the recording;
receiving, via the magnetic resonance apparatus, a compensation factor to compensate for interference signals caused by a chemical shift between the at least two different spin types;
computing, via the magnetic resonance apparatus, a compensation phase for the phases to be imprinted in the recording as a function of the compensation factor;
executing, via the magnetic resonance apparatus, the selected simultaneous recording of the measured data;
performing a reconstruction of image data from the measured data; and
displaying, via the magnetic resonance apparatus, the reconstructed image data,
wherein the computed compensation phase is applied to each respective one of the phases to be imprinted during the selected simultaneous recording of the measured data and/or during the reconstruction of image data from the measured data to reduce ghosting artifacts.

2. The method as claimed in claim 1 , wherein the received compensation factor is based upon a predetermined distribution of possible interference signals.

3. The method as claimed in claim 1 , wherein the received compensation factor is based upon a k-space position of the measured data that is to be recorded.

4. The method as claimed in claim 1 , wherein the received compensation factor is based upon a quantity of the at least two spin types in the examination object.

5. The method as claimed in claim 1 , wherein the received compensation factor is based upon at least one recording parameter set by the selected simultaneous recording.

6. The method as claimed in claim 5 , wherein the at least one recording parameter is based upon a suppression of a spin type or a signal strength of the at least two spin types in the examination object.

7. The method as claimed in claim 1 , wherein the received compensation factor is selected by a user.

8. The method as claimed in claim 1 , wherein the received compensation factor is selected based upon a random function.

9. The method as claimed in claim 1 , wherein the received compensation factor comprises a mean value of each one of a plurality of compensation factors applied in the selected simultaneous recording such that interference signals of more than one spin type are compensated.

10. The method as claimed in claim 1 , wherein the computing the compensation phase comprises computing a spatial shift (Δz) between a first spin type excited in the examination object and a second spin type excited in the examination object as a function of the received compensation factor.

11. A magnetic resonance apparatus for acquiring measured data that has been recorded simultaneously from at least two slices identified with an examination object comprising at least two different spin types, comprising:
a main magnet; and
control circuitry configured to cause the magnetic resonance apparatus to:
select a simultaneous recording of measured data from the at least two slices in which phases that generate field of view shifts are to be imprinted during the recording;
receive a compensation factor to compensate for interference signals caused by a chemical shift between the at least two different spin types;
compute a compensation phase for the phases to be imprinted in the recording as a function of the compensation factor;
execute the selected simultaneous recording of the measured data;
perform a reconstruction of image data from the measured data; and
display the reconstructed image data,

wherein the computed compensation phase is applied to each respective one of the phases to be imprinted during the selected simultaneous recording of the measured data and/or during the reconstruction of Mine data from the measured data to reduce ghosting artifacts.

12. A non-transitory computer-readable medium having instructions stored thereon that, when executed by one or more processors associated with a magnetic resonance apparatus, cause the magnetic resonance apparatus to acquire measured data that has been recorded simultaneously from at least two slices identified with an examination object comprising at least two different spin types by:
selecting a simultaneous recording of measured data from the at least two slices in which phases that generate field of view shifts are to be imprinted during the recording;
receiving a compensation factor to compensate for interference signals caused by a chemical shift between the at least two different spin types;
computing a compensation phase for the phases to be imprinted in the recording as a function of the compensation factor;
executing the selected simultaneous recording of the measured data;
perform a reconstruction of image data from the measured data; and
displaying the reconstructed image data,
wherein the computed compensation phase is applied to each respective one of the phases to be imprinted during the selected simultaneous recording of the measured data and/or during the reconstruction of image data from the measured data to reduce ghosting artifacts.

13. The method as claimed in claim 1 , wherein the received compensation factor is indicative of an amount of compensation of the interference signals for each one of the at least two different spin types.

14. The method of claim 13 , wherein the received compensation factor indicates a higher amount of compensation for a first interference signal of the at least two different spin types having a higher signal strength than a second interference signal of the at least two different spin types.

15. The method of claim 1 , wherein the received compensation factor indicates which of the at least two different spin types is to be compensated and an amount of compensation.

16. The method of claim 15 , wherein the received compensation factor comprises a value between 0 and 1.

17. The method of claim 1 , wherein the compensation phase is computed as a function of a zeroth moment of a gradient blip that is applied to imprint each respective one of the phases.

18. The method of claim 1 , wherein the compensation phase (dP) is computed for each of the at least two different spin types by evaluating:
dP=Υ*m 0 *( z 1−( c*AF*B 0/ A GS )), wherein:

Υ represents a gyromagnetic ratio,
m 0 represents a zeroth gradient moment of a gradient blip that is applied to imprint a respective one of the phases,
z1 represents an excited slice position of a respective one of the at least two different spin types,
c represents a chemical shift of the respective one of the at least two different spin types, and
AF represents the compensation factor,
A GS represents an amplitude of a slice selection gradient applied for a slice selection of radio frequency (RF) pulses, and
B0 represents a strength of the main magnetic field used for executing the selected simultaneous recording of the measured data.

19. The method as claimed in claim 1 , wherein the received compensation factor comprises a linear function of k-space position.

Assignees

• Siemens Healthcare Gmbh
• Siemens Healthineers Ag

Inventors

• Carinci Flavio
• Zeller Mario
• Paul Dominik

Classifications

• G01R33/4835 Primary

  of multiple slices · CPC title

• G01R33/56563

  caused by a distortion of the main magnetic field B0, e.g. temporal variation of the magnitude or spatial inhomogeneity of B0 (G01R33/56509, G01R33/56518, G01R33/56536 take precedence) · CPC title

• G01R33/56527

  due to chemical shift effects · CPC title

• A61B5/055 Primary

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title