Apparatus and method for decreasing bio-effects of magnetic gradient field gradients

Patent metadata

Field	Value
Publication number	US-9903922-B2
Application number	US-201715438269-A
Country	US
Kind code	B2
Filing date	Feb 21, 2017
Priority date	Jun 20, 2008
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A magnetic field generator includes a power source and a segmented or un-segmented coil connected to the power source to generate a time-varying magnetic field. Energy is applied to the coil so that the coil generates a time-varying magnetic field gradient with a magnitude of at least 1 milliTesla per meter and a rise-time of less than 1000 microseconds. The coil may be comprised of overlapping, non-overlapping or partially overlapping coil segments that may individually energized to further improve the operating characteristics of the coil to further decrease bio-effects in magnetic resonance imaging through the use of reduced pulse lengths and multi-phasic magnetic gradient pulses.

First claim

What is claimed is:

1. A magnetic field generator for imaging, the generator comprising:
a power source; and
at least one coil connected to the power source to generate a magnetic field,
wherein the magnetic field has a rise- and fall-time selected so as to be too short to elicit a neurological response in tissue, and
wherein the magnetic field has a slew rate of more than 200 T/m/s.

2. The generator of claim 1 , wherein the magnetic field has either a rise-time or fall-time of less than 100 microseconds.

3. The generator of claim 1 , wherein the magnetic field has either a rise-time or fall-time of less than 250 microseconds.

4. The generator of claim 1 , wherein the magnetic field has a gradient field strength of more than 10 mT/m.

5. The generator of claim 4 , wherein the generator produces a pulse sequence with multiple fast repetitions, wherein the repetitions increase the signal-to-noise ratio per pixel.

6. The generator of claim 1 , wherein the magnetic field has a slew rate of more than 500 T/m/s.

7. The generator of claim 1 , wherein the magnetic field has a slew rate of more than 1000 T/m/s.

8. The generator of claim 1 , wherein the magnetic field has a slew rate of more than 1000 T/m/s.

9. The generator of claim 1 , wherein the magnetic field has a slew rate of more than 1 million T/m/s.

10. The generator of claim 1 , wherein the magnetic field has a gradient field strength of more than 50 mT/m.

11. A method of imaging tissue using a magnetic field generator, wherein the generator comprises a power source and at least one coil, the method comprising:
generating a magnetic field that has a rise- and fall-time selected so as to be too short to elicit a neurological response in tissue,
wherein the magnetic field has a slew rate of more than 200 T/m/s.

12. The method of claim 11 , wherein the magnetic field has either a rise-time or fall-time of less than 100 microseconds.

13. The method of claim 11 , wherein the magnetic field has either a rise-time or fall-time of less than 250 microseconds.

14. The method of claim 11 , wherein the magnetic field has a gradient field strength of more than 10 mT/m.

15. The method of claim 11 , wherein the magnetic field has a slew rate of more than 500 T/m/s.

16. The method of claim 11 , wherein the magnetic field has a slew rate of more than 1000 T/m/s.

17. The method of claim 11 , wherein the magnetic field has a slew rate of more than 1000 T/m/s.

18. The method of claim 11 , wherein the magnetic field has a slew rate of more than 1 million T/m/s.

19. The method of claim 11 , wherein a pulse sequence is generated with multiple fast repetitions, wherein the repetitions increase the signal-to-noise ratio per pixel.

20. The method of claim 11 , wherein at least one section of a pulse sequence used to collect data about a body part is repeated more than 100 times per second.

21. The method of claim 11 , wherein at least one section of a pulse sequence used to collect data about a body part is repeated more than 100 times per second.

22. The method of claim 11 , wherein at least one section of a pulse sequence used to collect data about a body part is repeated more than 1000 times per second.

23. The method of claim 11 , wherein at least one section of a pulse sequence used to collect data about a body part is repeated more than 10000 times per second.

24. The method of claim 11 , wherein the at least one coil is introduced into a magnetic resonance system to improve visualization of a body part.

25. The method of claim 11 , wherein the magnitude of the magnetic field is more than 50 mT.

26. The method of claim 11 , wherein the magnitude of the magnetic field is more than 100 mT.

27. The method of claim 11 , wherein the magnitude of the magnetic field is more than 200 mT.

Assignees

• Weinberg Medical Physics Inc

Inventors

• Weinberg Irving N
• Stepanov Pavel

Classifications

• G01R33/543

  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 title

• G01R33/36

  Electrical details, e.g. matching or coupling of the coil to the receiver · CPC title

• A61B5/055

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

• G01R33/3852

  Gradient amplifiers; means for controlling the application of a gradient magnetic field to the sample, e.g. a gradient signal synthesizer · CPC title

• G01R33/385

  using gradient magnetic field coils · CPC title