Determination of a measuring sequence for a magnetic resonance system
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.
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.
18. The computer program product as claimed in claim 17 , 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.
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.