Method for the control of a magnetic resonance system

Patent metadata

Field	Value
Publication number	US-9547064-B2
Application number	US-201213645093-A
Country	US
Kind code	B2
Filing date	Oct 4, 2012
Priority date	Oct 4, 2011
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

A method for the control of a magnetic resonance system is provided. In a test phase before a magnetic resonance measurement, a test high-frequency pulse with several parallel individual high-frequency pulses is transmitted with a transmitter antenna arrangement over various different high-frequency transmitter channels. At lower transmitter power, the test high-frequency pulse generates essentially the same field distribution as an excitation high-frequency pulse to be transmitted during a subsequent magnetic resonance measurement. A high-frequency field generated by this test high-frequency pulse is measured in at least one area of a local pulse arrangement, and on the basis of the high-frequency field measured, a high-frequency field value that is to be anticipated at the local coil arrangement during the subsequent magnetic resonance measurement is determined. The control of the magnetic resonance system during a later magnetic resonance measurement includes taking the high-frequency field value into account.

First claim

The invention claimed is:

1. A method for the control of a magnetic resonance system, the magnetic resonance system comprising a transmitter antenna arrangement having a plurality of independent high-frequency transmitter channels, and a local coil arrangement arranged in the magnetic resonance system, the method comprising:
transmitting, with the transmitter antenna arrangement, a test high-frequency pulse with a plurality of parallel individual high-frequency pulses before a magnetic resonance measurement in a test phase, over the plurality of independent high-frequency transmitter channels, the test high-frequency pulse, with lower transmitter power of −60 to 20 dBm, generating essentially the same field distribution as an excitation high-frequency pulse to be transmitted during a subsequent magnetic resonance measurement;
measuring a high-frequency field created by the test high-frequency pulse in at least one area of the local coil arrangement;
determining a high-frequency field value that is to be anticipated during the subsequent magnetic resonance measurement at the local coil arrangement on the basis of the high-frequency field measured, and determining a temperature value to be anticipated by the high-frequency field at, in, or at and in the local coil arrangement; and
controlling the magnetic resonance system during a later magnetic resonance measurement, the controlling comprising taking account of the high-frequency field value.

2. The method as claimed in claim 1 , wherein measuring the high-frequency field comprises measuring the high-frequency field using a number of antenna elements arranged at the local coil arrangement, integrated in the local coil arrangement, or arranged at the local coil arrangement and integrated in the local coil arrangement.

3. The method as claimed in claim 2 , wherein measuring the high-frequency field comprises measuring the high-frequency field using at least a portion of the antenna elements of the local coil arrangement.

4. The method as claimed in claim 1 , wherein measuring the high-frequency field comprises measuring the high-frequency field using a number of test antenna elements.

5. The method as claimed in claim 1 , wherein determining the high-frequency field value comprises determining a local high-frequency field amplitude.

6. The method as claimed in claim 1 , wherein determining the high-frequency field value comprises determining a mean quadratic high-frequency field amplitude.

7. The method as claimed in claim 1 , further comprising determining a voltage value to be anticipated.

8. The method as claimed in claim 1 , further comprising calculating, on the basis of the high-frequency field value, a physical high-frequency load value of an examination object that is to be anticipated, caused by the transmitter field.

9. The method as claimed claim 1 , further comprising transmitting, in the test phase, a test pulse sequence, the test pulse sequence comprising test high-frequency that correspond to at least one section of a pulse sequence to be transmitted in the later magnetic resonance measurement.

10. The method as claimed in claim 7 , further comprising comparing the high-frequency field value, the temperature value, the voltage value, a physical high-frequency load value, or a combination thereof with a limit value; and restricting the later magnetic resonance measurement as a function of the comparison.

11. The method as claimed in claim 10 , further comprising determining or modifying a pulse frequency for the later magnetic resonance measurement or another later magnetic resonance measurement as a function of the high-frequency field value, the voltage value, the temperature value, the physical high-frequency load value, the limit value, or a combination thereof.

12. The method as claimed claim 2 , further comprising determining, before the test phase and in a calibration phase, calibration values, the determining comprising transmitting a calibration high-frequency pulse with known high-frequency field distribution for the antenna elements.

13. The method as claimed in claim 3 , wherein measuring the high-frequency field comprises measuring the high-frequency field using a number of test antenna elements.

14. The method as claimed in claim 3 , wherein determining the high-frequency field value comprises determining a local high-frequency field amplitude.

15. The method as claimed in claim 3 , wherein determining the high-frequency field value comprises determining a mean quadratic high-frequency field amplitude.

16. The method as claimed in claim 3 , further comprising determining a temperature value to be anticipated by the high-frequency field at, in, or at and in the local coil arrangement, a voltage value to be anticipated, or the temperature value and the voltage value.

17. The method as claimed in claim 3 , further comprising calculating, on the basis of the high-frequency field value, a physical high-frequency load value of an examination object that is to be anticipated, caused by the transmitter field.

18. A control device for the control of a magnetic resonance system with a plurality of independent high-frequency transmitter channels and a local coil arrangement, wherein the control device is configured to transmit an excitation pulse with individual high-frequency pulses over various different high-frequency transmitter channels of the plurality of independent high-frequency transmitter channels in order to carry out a desired magnetic resonance measurement on the basis of a predetermined control sequence, the control device comprising:
a test unit comprising:
a test signal transmitter interface operable, in a test phase before a magnetic resonance measurement, to initiate transmission of a test high-frequency pulse with at least a portion of the parallel individual high-frequency pulses over the various different high-frequency transmitter channels, the test high-frequency pulse, at lower transmitter power of −60 to 20 dBm, generating essentially the same field distribution as an excitation high-frequency pulse to be transmitted during a subsequent magnetic resonance measurement;
a test value measurement interface operable, in the test phase, to initiate measurement of a high-frequency field generated by the test high-frequency pulse in at least one area of the local coil arrangement;
an analysis unit operable to determine a high-frequency field value to be anticipated at the local coil arrangement during the subsequent magnetic resonance measurement on the basis of the high-frequency field measured, and operable to determine a temperature value to be anticipated by the high-frequency field at, in, or at and in the local coil arrangement; and
a monitor unit configured to control the magnetic resonance system during a later magnetic resonance measurement by taking account of the high-frequency field value.

19. A magnetic resonance system comprising:
a plurality of independent high-frequency transmitter channels;
a basic field magnet system;
a transmitter antenna system comprising a plurality of independent high-frequency transmitter channels;
a local coil arrangement; and
a control device for the control of the magnetic resonance system, wherein the control device is configured to transmit an excitation pulse with individual high-frequency pulses over various different high-frequency transmitter channels of the plurality of independent high-frequency transmitter channels in order to carry out a desired magnetic resonance measurement on the basis of a predeterm

Assignees

• Biber Stephan
• Greim Helmut
• Nistler Juergen
• Speckner Thorsten
• Siemens Ag

Inventors

• Biber Stephan
• Greim Helmut
• Nistler Juergen
• Speckner Thorsten

Classifications

• G01R33/583 Primary

  Calibration of signal excitation or detection systems, e.g. for optimal RF excitation power or frequency (G01R33/246 takes precedence) · CPC title

• G01R33/341

  comprising surface coils · CPC title