Determination of a Measuring Sequence for a Magnetic Resonance System

• US 20130200893A1
• Filed: 02/01/2013
• Published: 08/08/2013
• Est. Priority Date: 02/03/2012
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Aurelien Stalder, Bjorn Heismann
• Inventors: Heismann, Bjrn, Nittka, Mathias, Speier, Peter, Stalder, Aurlien
• Granted Patent: US 9,645,216 B2
• Time in Patent Office: Days
• US Class Current: 324/314
• CPC Class Codes: G01R 33/38 Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
• CPC Class Codes: G01R 33/3854 means for active and/or passive vibration damping or acoustical noise suppression in gradient magnet coil systems
• CPC Class Codes: G01R 33/543 Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription G01R33/546 takes precedence
• CPC Class Codes: G01R 33/56518 due to eddy currents, e.g. caused by switching of the gradient magnetic field

Abstract

A method and a measuring-sequence-determining device for determining a measuring sequence for a magnetic resonance system based on at least one intra-repetition-interval time parameter are provided. During the determination of the measuring sequence in a gradient-optimization method, gradient-pulse parameters of the measuring sequence are automatically optimized to reduce at least one gradient-pulse-parameter maximum value. As a boundary condition in the gradient-optimization method, the intra-repetition-interval time parameter is kept constant at least within a specified tolerance value.

Claims

1. A method for determining a measuring sequence for a magnetic resonance system based on at least one intra-repetition-interval time parameter, the method comprising:

automatically optimizing, during the determination of the measuring sequence in a gradient-optimization method, gradient-pulse parameters of the measuring sequence in order to reduce at least one gradient-pulse-parameter maximum value,

wherein, as a boundary condition in the gradient-optimization method, the intra-repetition-interval time parameter is kept constant at least within a specified tolerance value.

2. The method as claimed in claim 1, wherein the gradient-pulse parameters comprise a slew rate, a gradient amplitude of a gradient pulse of the measuring sequence, or the slew rate and the gradient amplitude.

3. The method as claimed in claim 1, wherein the measuring sequence comprises an echo sequence, and the intra-repetition-interval time parameter comprises an echo time.

4. The method as claimed in claim 1, further comprising optimizing, in the gradient-optimization method, the at least one gradient-pulse-parameter maximum value.

5. The method as claimed in claim 4, further comprising checking, in the gradient-optimization method, the at least one gradient-pulse-parameter maximum value in a sequence-determining process, to see whether, while observing the boundary condition of keeping the intra-repetition-interval time parameter constant within the specified tolerance value, the specified gradient-pulse-parameter maximum value is usable to determine the measuring sequence.

6. The method as claimed in claim 4, wherein the gradient-optimization method comprises an iteration method, the iteration method comprising:

initially specifying a gradient-pulse-parameter maximum value as a start value;

reducing the gradient-pulse-parameter maximum value in a plurality of iteration steps with a defined increment;

performing, in each iteration step of the plurality of iteration steps with the current gradient-pulse-parameter maximum value, a sequence-determining process for determining the measuring sequence while keeping the intra-repetition-interval time parameter constant within the specified tolerance value; and

performing, on the successful determination of the measuring sequence, a new iteration step up to a specified abort criterion.

7. The method as claimed in claim 6, further comprising aborting the iteration method when, in an iteration step with the current gradient-pulse-parameter maximum value, no successful determination of the measuring sequence is possible while keeping the intra-repetition-interval time parameter constant within the specified tolerance value.

8. The method as claimed in claim 7, further comprising outputting, following the abortion of the iteration method, a gradient-pulse-parameter maximum value that is above the last current gradient-pulse-parameter maximum value as the at least one optimum gradient-pulse-parameter maximum value.

9. The method as claimed in claim 8, wherein the last current gradient-pulse-parameter maximum value is a penultimate current gradient-pulse-parameter maximum value.

10. The method as claimed in claim 4, further comprising specifying a global gradient-pulse-parameter maximum value as the start value.

11. The method as claimed in claim 1, further comprising determining an individual gradient-pulse-parameter maximum value separately for an individual pulse segment of a gradient pulse.

12. The method as claimed in claim 1, further comprising determining an individual gradient-pulse-parameter maximum value separately for an individual complete gradient pulse.

13. The method as claimed in claim 1, further comprising determining an individual gradient-pulse-parameter maximum value separately for a functional group of gradient pulses.

14. A method for operating a magnetic resonance system, the method comprising:

determining a measuring sequence for the magnetic resonance system based on at least one intra-repetition-interval time parameter, the determining comprising automatically optimizing, during the determination of the measuring sequence in a gradient-optimization method, gradient-pulse parameters of the measuring sequence in order to reduce at least one gradient-pulse-parameter maximum value, wherein, as a boundary condition in the gradient-optimization method, the intra-repetition-interval time parameter is kept constant at least within a specified tolerance value; and

operating the magnetic resonance system using the determined measuring sequence.

15. A measuring-sequence-determining device for determining a measuring sequence for a magnetic resonance system, the measuring-sequence-determining device comprising:

an input interface operable to acquire at least one intra-repetition-interval time parameter; and

a measuring-sequence-calculating unit configured to determine the measuring sequence on the basis of control parameters,

wherein the measuring-sequence-determining device is configured such that, during the determination of the measuring sequence in a gradient-optimization method, the measuring-sequence-determining device automatically optimizes gradient-pulse parameters of the measuring sequence to reduce at least one gradient-pulse-parameter maximum value, and

wherein, as a boundary condition in the gradient-optimization method, the intra-repetition-interval time parameter is kept constant at least within a specified tolerance value.

16. A magnetic resonance system comprising:

a high-frequency transmission system comprising;

a gradient system; and

a control device configured to control the high-frequency transmission system and the gradient system in order to carry out a desired measurement based on a specified measuring sequence; and

a measuring-sequence-determining device for determining a measuring sequence for the magnetic resonance system, the measuring-sequence-determining device comprising;

an input interface operable to acquire at least one intra-repetition-interval time parameter; and

a measuring-sequence-calculating unit configured to determine the measuring sequence on the basis of control parameters,

wherein the measuring-sequence-determining device is configured such that, during the determination of the measuring sequence in a gradient-optimization method, the measuring-sequence-determining device automatically optimizes gradient-pulse parameters of the measuring sequence to reduce at least one gradient-pulse-parameter maximum value,

wherein, as a boundary condition in the gradient-optimization method, the intra-repetition-interval time parameter is kept constant at least within a specified tolerance value, and

wherein the measuring-sequence-determining device is operable to forward the measuring sequence to the control device.

17. A computer program product loadable directly into a non-transitory computer-readable medium of a measuring-sequence-determining device, the computer program product including instructions executable by the measuring-sequence-determining device to determine a measuring sequence for a magnetic resonance system, the instructions comprising:

automatically optimizing, during the determination of the measuring sequence in a gradient-optimization method, gradient-pulse parameters of the measuring sequence in order to reduce at least one gradient-pulse-parameter maximum value,

wherein, as a boundary condition in the gradient-optimization method, an intra-repetition-interval time parameter is kept constant at least within a specified tolerance value.

19. The computer program product as claimed in claim 17, wherein the measuring sequence comprises an echo sequence, and the intra-repetition-interval time parameter comprises an echo time.

20. The computer program product as claimed in claim 17, wherein the instructions further comprise optimizing, in the gradient-optimization method, the at least one gradient-pulse-parameter maximum value.

18. The computer program product as claimed in claim 71, wherein the gradient-pulse parameters comprise a slew rate, a gradient amplitude of a gradient pulse of the measuring sequence, or the slew rate and the gradient amplitude.