Artificially structured b1 magnetic field generator for mri and nmr devices

Patent metadata

Field	Value
Publication number	US-2016018491-A1
Application number	US-201414334368-A
Country	US
Kind code	A1
Filing date	Jul 17, 2014
Priority date	Jul 17, 2014
Publication date	Jan 21, 2016
Grant date	—

Abstract

Described embodiments include an apparatus, and a method. An apparatus includes an array of at least two artificially structured electromagnetic unit cells. The at least two artificially structured electromagnetic unit cells are configured to generate a pulse of radiofrequency magnetic field B 1 orientated transverse to the quasistatic magnetic field B 0 parallel to the z-axis of the bore of a MRI or NMR device by transforming an incident pulse of radiofrequency electromagnetic waves. The generated pulse having magnetic field intensity sufficient to excite a detectable magnetic resonance in magnetically active nuclei located within at least a portion of an examination region located within the bore. The apparatus includes a radiofrequency electromagnetic wave conducting structure configured to distribute a received pulse of radiofrequency electromagnetic waves as an incident pulse of radiofrequency electromagnetic waves to the at least two artificially structured electromagnetic unit cells.

First claim

What is claimed is:

1 . An apparatus comprising:
a radiofrequency electromagnetic wave conducting structure configured to distribute a received pulse of radiofrequency electromagnetic waves as an incident pulse of radiofrequency electromagnetic waves to an array of at least two artificially structured electromagnetic unit cells; and the array of the at least two artificially structured electromagnetic unit cells, the at least two artificially structured electromagnetic unit cells configured to generate a pulse of radiofrequency magnetic field B 1 orientated transverse to a quasistatic magnetic field B 0 parallel to a z-axis of a bore of a magnetic resonant imaging or a nuclear magnetic resonant device by transforming the incident pulse of radiofrequency electromagnetic waves, and the generated pulse having a magnetic field intensity sufficient to excite a detectable magnetic resonance in magnetically active nuclei located within at least a portion of an examination region located within the bore.

2 . The apparatus of claim 1 , wherein the magnetic field B 0 is created by a primary magnet of the magnetic resonant imaging or the nuclear magnetic resonant device.

3 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells includes at least two metamaterial unit cells.

4 . The apparatus of claim 1 , wherein a unit cell of the at least two artificially structured electromagnetic unit cells includes an artificially structured metamaterial unit cell with a strong magnetic response.

5 . The apparatus of claim 4 , wherein a unit cell of the at least two artificially structured electromagnetic unit cells includes an artificially structured, highly inductive metamaterial unit cells.

6 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells includes at least two periodically arranged, artificially structured electromagnetic unit cells.

7 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells includes at least two artificially structured sub-wavelength electromagnetic unit cells.

8 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells include split ring resonator inserts optimized to generate a highly inductive electromagnetic near field.

9 . (canceled)

10 . (canceled)

11 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells respectfully include a spiral insert optimized to generate a high inductance density.

12 . (canceled)

13 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells respectively include a conical helical insert optimized to generate a high inductance density.

14 . (canceled)

15 . The apparatus of claim 13 , wherein the at least two artificially structured electromagnetic unit cells respectively include three orthogonally oriented conical helical inserts optimized to generate a high inductance density.

16 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells includes a pyramidal helical insert optimized to generate a high inductance density.

17 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells are configured to induce a B 1 magnetic field component orthogonal to the z-axis.

18 . The apparatus of claim 17 , wherein the at least two artificially structured electromagnetic unit cells are respectively configured to induce a first B 1 magnetic field component orthogonal to the z-axis and a second B 1 magnetic field component orthogonal to the first B 1 magnetic field component.

19 . The apparatus of claim 17 , wherein the at least two artificially structured electromagnetic unit cells are configured to induce magnetic field B 1 components in all three mutually orthogonal orientations.

20 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells include a sub-wavelength arrangement of magnetic dipole unit cells.

21 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells include a sub-wavelength arrangement of magnetic multipole unit sources.

22 . The apparatus of claim 1 , wherein the array is configured to generate a near-field region magnetic field B 1 .

23 . The apparatus of claim 1 , wherein the at least two unit cells are configured to generate a pulse of a tunable radiofrequency magnetic field B 1 .

24 . The apparatus of claim 23 , wherein the tunable radiofrequency magnetic field B 1 includes a frequency, amplitude, or polarization tunable radiofrequency magnetic field B 1 .

25 . (canceled)

26 . The apparatus of claim 1 , wherein the array is configured to be coaxially disposed about the z-axis.

27 . The apparatus of claim 1 , wherein the array includes an arcuate shape dimensioned to be mounted or positioned within at least a portion of the bore of the magnetic resonant imaging or the nuclear magnetic resonant device.

28 . (canceled)

29 . (canceled)

30 . (canceled)

31 . The apparatus of claim 1 , wherein the array includes two arcuate shaped portions, each dimensioned to be less than 180-degrees of the circumference of the bore, and mounted or positioned facing each other across the z-axis.

32 . The apparatus of claim 1 , wherein the array has a cylindrical or an annular shape dimensioned to be mounted or positioned within the bore of the magnetic resonant imaging or the nuclear magnetic resonant device.

33 . (canceled)

34 . The apparatus of claim 1 , wherein the array includes two generally planar portions, each configured to be generally mounted or positioned facing the other across the z-axis.

35 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells are configured to generate a highly inductive electromagnetic near-field B 1 .

36 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells are configured to generate a magnetic field-dominant radiofrequency near-field with magnetic (B 1 ) and electric (E) field intensities such that (B 1 c)/E 1 >1 (where “c” is the speed of light).

37 . The apparatus of claim 36 , wherein the at least two artificially structured electromagnetic unit cells are configured to generate a magnetic field-dominant RF near-field where (B 1 c)/E 1 >10.

38 . The apparatus of claim 1 , wherein the at least two artificially structured electromagnetic unit cells are configured to generate a magnetic field B 1 that includes a gradient intensity orientated transverse to the z-axis.

39 . (canceled)

40 . The apparatus of claim 1 , wherein the pulse of radiofrequency magnetic field B 1 is linearly polarized relative to the z-axis.

41 . The apparatus of claim 1 , wherein the pulse of radiofrequency magnetic field B 1 is circularly polarized relative to the z-axis.

42 . The apparatus of claim

Assignees

• Elwha Llc

Inventors

• Driscoll Tom
• Smith David R
• Urzhumov Yaroslav A

Classifications

• G01R33/3621

  NMR receivers or demodulators, e.g. preamplifiers, means for frequency modulation of the MR signal using a digital down converter, means for analog to digital conversion [ADC] or for filtering or processing of the MR signal such as bandpass filtering, resampling, decimation or interpolation · CPC title

• G01R33/3614 Primary

  RF power amplifiers · CPC title

• G01R33/3607

  RF waveform generators, e.g. frequency generators, amplitude-, frequency- or phase modulators or shifters, pulse programmers, digital to analog converters for the RF signal, means for filtering or attenuating of the RF signal · CPC title

• G01R33/36

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

• G01R33/345

  of waveguide type (G01R33/343 takes precedence) · CPC title