MULTI-CHANNEL METHOD AND DEVICE TO EVALUATE MAGNETIC RESONANCE SIGNALS, WITH REDUCED NUMBER OF CHANNELS

• US 20100225317A1
• Filed: 03/05/2010
• Published: 09/09/2010
• Est. Priority Date: 03/06/2009
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Biber, Stephan
• Granted Patent: US 8,536,867 B2
• Time in Patent Office: Days
• US Class Current: 324/309
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• 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 33/56 Image enhancement or correction, e.g. subtraction or averaging techniques , e.g. improvement of signal-to-noise ratio and resolution
• CPC Class Codes: G01R 33/5608 Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels image data processing or generation, in general G06T

Abstract

An optimized processing of data of multiple local coils is enabled by a device and a method to evaluate signals received with coils of a magnetic resonance tomography apparatus, wherein first signals are generated by means of coils via magnetic fields coming from a body, wherein a region in the body is defined, wherein weighting factors are calculated with the use of the first signals, wherein second signals are generated with the coils from magnetic fields coming from a body, wherein signals weighted with the use of the weighting factors are calculated from the second signals, wherein the weighted signals are processed further.

Claims

1. A method to evaluate magnetic resonance signals comprising the steps of:

generating first signals with coils in a magnetic resonance tomography apparatus by interaction of the coils with magnetic fields emanating from a defined region of a subject in the magnetic resonance tomography apparatus;

supplying said first signals to a processor and, in said processor, automatically calculating weighting factors from said first signals;

generating second signals with said coils by interaction of the coils with magnetic fields emanating from the region of the subject;

supplying said second signals to said processor and, in said processor, automatically calculating weighted signals by weighting said second signals with said weighting factors; and

making said weighted signals available at an output of said processor.

2. A method as claimed in claim 1 comprising generating said second signals with a higher resolution than said first signals.

3. A method as claimed in claim 1 comprising generating said first signals with a magnetic resonance data acquisition technique that generates a tomographic image of the region of the subject with fewer than 50×

50 pixels.

4. A method as claimed in claim 1 comprising generating said first signals with a magnetic resonance data acquisition technique that generates a tomographic image of the region of the subject with fewer than 10×

10 pixels.

5. A method as claimed in claim 1 comprising generating said first signals in a pre-scan data acquisition implemented before a diagnostic data acquisition.

6. A method as claimed in claim 1 comprising generating said first signals in an adjustment measurement.

7. A method as claimed in claim 1 comprising generating said first signals by acquiring magnetic resonance data from the region of the subject and entering said magnetic resonance data into a plurality of lines of k-space, and using entries in non-central lines of k-space as said first signals.

8. A method as claimed in claim 1 comprising, in said processor, automatically determining, from said first signals, a point in said defined region exhibiting a lowest signal-to-noise ratio and calculating said weighting factors relative to said point.

9. A method as claimed in claim 1 comprising, in said processor, determining, from said first signals, a sub-region within said region that is best visible in a resulting magnetic resonance image, and calculating said weighting factors with respect to said sub-region.

10. A method as claimed in claim 1 wherein each of said first signals has a magnitude, and calculating said weighting factors with an amplitude and phase dependent on the respective magnitudes of the first signals.

11. A method as claimed in claim 1 comprising determining said weighting factors by iteratively evaluating respective points in said region, represented by said first signals, with respect to a characteristic embodied in said first signals, and calculating said weighting factors with respect to a point at which said characteristic is best for generating a resulting magnetic resonance image from said weighted signals.

12. A method as claimed in claim 1 comprising calculating said weighting factors with respect to the center of gravity of said region.

13. A method as claimed in claim 1 comprising digitizing said second signals, and weighting said second signals with said weighting factors, to obtain said weighted signals, before digitizing said second signals.

14. A method as claimed in claim 1 comprising digitizing said second signals, and weighting said second signals with said weighting factors, to obtain said weighted signals, after digitizing said second signals.

15. A method as claimed in claim 1 wherein said first signals are first analog signals and wherein said second signals are second analog signals, and comprising operating on each of said first and second analog signals in said processor to calculate said weighting factors and to generate said weighted signals.

16. A method as claimed in claim 1 wherein said first signals are first analog signals and said second signals are second analog signals, and comprising digitizing said first analog signals in said processor to obtain first digital signals and calculating said weighting factors digitally from said first digital signals, and digitizing said second analog signals in said processor to generate second digital signals, and digitally weighting said digital second signals with said digital weighting factors, to obtain digital weighted signals.

17. A device to evaluate magnetic resonance signals comprising:

an operating unit configured to operate a magnetic resonance tomography apparatus to generate first signals by interaction of the coils with magnetic fields emanating from a defined region of a subject in the magnetic resonance tomography apparatus;

a processor supplied with said first signals configured to automatically calculate weighting factors from said first signals;

said operating unit being configured to operate said magnetic resonance tomography apparatus to generate second signals with said coils by interaction of the coils with magnetic fields emanating from the region of the subject;

said processor being supplied with said second signals and being configured to automatically calculate weighted signals by weighting said second signals with said weighting factors; and

said processor being configured to make said weighted signals available at an output of said processor.

18. A device as claimed in claim 17 wherein said processor is configured to automatically determine, from said first signals, a point in said defined region exhibiting a lowest signal-to-noise ratio and calculating said weighting factors relative to said point.

19. A device as claimed in claim 17 wherein said processor is configured to determine, from said first signals, a sub-region within said region that is best visible in a resulting magnetic resonance image, and calculating said weighting factors with respect to said sub-region.

20. A device as claimed in claim 17 wherein each of said first signals has a magnitude, and wherein said processor is configured to calculate said weighting factors with an amplitude and phase dependent on the respective magnitudes of the first signals.

21. A device as claimed in claim 17 wherein said processor is configured to determine said weighting factors by iteratively evaluating respective points in said region, represented by said first signals, with respect to a characteristic embodied in said first signals, and to calculate said weighting factors with respect to a point at which said characteristic is best for generating a resulting magnetic resonance image from said weighted signals.

22. A device as claimed in claim 17 wherein said processor is configured to calculate said weighting factors with respect to the center of gravity of said region.

23. A device as claimed in claim 17 wherein said processor is configured to digitize said second signals, and weighting said second signals with said weighting factors, to obtain said weighted signals, before digitizing said second signals.

24. A device as claimed in claim 17 wherein said processor is configured to digitize said second signals, and weighting said second signals with said weighting factors, to obtain said weighted signals, after digitizing said second signals.

25. A device as claimed in claim 17 wherein said first signals are first analog signals and wherein said second signals are second analog signals, and wherein said processor is configured to operate on each of said first and second analog signals to calculate said weighting factors and to generate said weighted signals.

26. A device as claimed in claim 17 wherein said first signals are first analog signals and said second signals are second analog signals, and wherein said processor is configured to digitize said first analog signals to obtain first digital signals and calculate said weighting factors digitally from said first digital signals, and digitizing said second analog signals in said processor to generate second digital signals, and digitally weight said digital second signals with said digital weighting factors, to obtain digital weighted signals.

27. A magnetic resonance tomography apparatus to evaluate magnetic resonance signals comprising:

a magnetic resonance data acquisition unit comprising detection coils;

an operating unit configured to operate said coils in said magnetic resonance data acquisition unit to generate first signals by interaction of the coils with magnetic fields emanating from a defined region of a subject in the magnetic resonance tomography apparatus;

a processor supplied with said first signals and configured to automatically calculate weighting factors from said first signals;

said operating unit being configured to operate said magnetic resonance data acquisition unit to generate second signals with said coils by interaction of the coils with magnetic fields emanating from the region of the subject;

said second signals being supplied to said processor and said processor being configured to automatically calculate weighted signals by weighting said second signals with said weighting factors; and

said processor being configured to make said weighted signals available at an output of said processor.

28. An apparatus as claimed in claim 27 wherein said operating unit is configured to operate said magnetic resonance data acquisition unit to generate said second signals with a higher resolution than said first signals.

29. An apparatus as claimed in claim 27 wherein said operating unit is configured to operate said magnetic resonance data acquisition unit to generate said first signals with a magnetic resonance data acquisition technique that generates a tomographic image of the region of the subject with fewer than 50×

50 pixels.

30. An apparatus as claimed in claim 27 wherein said operating unit is configured to operate said magnetic resonance data acquisition unit to generate said first signals with a magnetic resonance data acquisition technique configured to generate a tomographic image of the region of the subject with fewer than 10×

10 pixels.

31. An apparatus as claimed in claim 27 wherein said operating unit is configured to operate said magnetic resonance data acquisition unit to generate said first signals in a pre-scan data acquisition implemented before a diagnostic data acquisition.

32. An apparatus as claimed in claim 27 wherein said operating unit is configured to operate said magnetic resonance data acquisition unit to generate said first signals in an adjustment measurement.

33. An apparatus as claimed in claim 27 wherein said operating unit is configured to operate said magnetic resonance data acquisition unit to generate said first signals by acquiring magnetic resonance data from the region of the subject and entering said magnetic resonance data into a plurality of lines of k-space, and using entries in non-central lines of k-space as said first signals.