Magnetic resonance system and method employing a digital squid

• US 9,618,591 B1
• Filed: 02/05/2016
• Issued: 04/11/2017
• Est. Priority Date: 11/24/2009
• Status: Active Grant

• Current Assignee: Johnson Revocable Trust
• Original Assignee: Hypres, Inc.
• Inventors: Radparvar, Masoud, Kadin, Alan M., Track, Elie K., Hitt, Richard E.
• Primary Examiner(s): Arana, Louis
• Application Number:
  US15/017,191
• Time in Patent Office: 431 Days
• Field of Search: 324322, 324318, 324314
• CPC Class Codes: G01R 33/323 Detection of MR without the use of RF or microwaves, e.g. force-detected MR, thermally detected MR, MR detection via electrical conductivity, optically detected MR
• CPC Class Codes: G01R 33/326 involving a SQUID
• CPC Class Codes: G01R 33/3621 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 Class Codes: G01R 33/445 MR involving a non-standard magnetic field B0, e.g. of low magnitude as in the earth's magnetic field or in nanoTesla spectroscopy, comprising a polarizing magnetic field for pre-polarisation, B0 with a temporal variation of its magnitude or direction such as field cycling of B0 or rotation of the direction of B0, or spatially inhomogeneous B0 like in fringe-field MR or in stray-field imaging
• CPC Class Codes: G01R 33/50 based on the determination of relaxation times , e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences
• CPC Class Codes: G01R 33/567 gated by physiological signals , i.e. synchronization of acquired MR data with periodical motion of an object of interest, e.g. monitoring or triggering system for cardiac or respiratory gating

Abstract

A magnetic resonance system, comprising at least one SQUID, configured to receive a radio frequency electromagnetic signal, in a circuit configured to produce a pulsatile output having a minimum pulse frequency of at least 1 GHz which is analyzed in a processor with respect to a timebase, to generate a digital signal representing magnetic resonance information. The processor may comprise at least one rapid single flux quantum circuit. The magnetic resonance information may be image information. A plurality of SQUIDs may be provided, fed by a plurality of antennas in a spatial array, to provide parallel data acquisition. A broadband excitation may be provided to address a range of voxels per excitation cycle. The processor may digitally compensate for magnetic field inhomogeneities.

Claims

1. A magnetic resonance system comprising:

at least one input configured to receive concurrent representations of a plurality of magnetic resonance signals emitted from an object characteristic of a spatial range of volumetric regions extending beyond a single plane;

at least one sampler, each sampler being configured to produce an oversampled broadband data stream representing the concurrent representations of the magnetic resonance signals at a rate of at least 1 giga-samples per second; and

at least one processor configured to;

receive the oversampled broadband data stream from the at least one sampler;

process the oversampled broadband data stream dependent on at least spatial differences in magnetic resonance frequency of the respective concurrent representations of the magnetic resonant signals; and

generate a matrix of spatial data representing the object in dependence on at least the spatial differences in magnetic resonance frequency of the respective concurrent representations of the magnetic resonant signals representing properties of the spatial range of the volumetric regions of the object.

2. The system of claim 1, wherein the received concurrent representations of the plurality of magnetic resonance signals comprise a frequency bandwidth of at least 100 kHz.

3. The system of claim 1, further comprising a magnetic field generator configured to maintain an inhomogeneous magnetic field around the object.

4. The system of claim 3, wherein the magnetic field has a strength of less than about 0.4 T.

5. The system of claim 1, wherein the at least one sampler comprises at least one superconducting digital flux detector.

6. The system of claim 5, wherein the at least one superconducting digital flux detector comprises at least one Josephson junction configured in a circuit which functions as at least one of a digital superconducting quantum interference device (digital SQUID) and a superconducting quantum interference filter (SQIF).

7. The system of claim 5, wherein the at least one superconducting digital flux detector comprises a device which operates at a superconducting temperature of below about 20K, and is configured to generate single-flux-quantum (SFQ) pulses.

8. The system of claim 1, wherein the at least one sampler comprises a superconducting multi-chip module.

9. The system of claim 1, further comprising at least one antenna comprising at least one superconducting component, the at least one processor being further configured to produce an image representing magnetic resonance properties of the object in at least one plane across the object.

10. The system of claim 1, wherein each at least one input receives a respective signal from a magnetic gradiometer having a derivative property greater than zero.

11. The system of claim 1, wherein the at least one processor is configured to acquire data representing a plurality of magnetic resonance slices through the object concurrently.

12. The imaging system of claim 1, wherein the at least one input comprises an array of inputs receiving concurrent representations of the plurality of magnetic resonance signals from a plurality of magnetic flux antennas arranged in a spatial array and the at least one sampler comprises a plurality of digital flux detectors, each connected to a respective magnetic flux antenna.

13. The system of claim 1, further comprising a dynamic magnetic field generator configured to generate a magnetic field surrounding the object that varies over time and space.

14. A magnetic resonance method comprising:

receiving a concurrent plurality of magnetic resonance signals emitted from an object characteristic of a spatial range of volumetric regions extending beyond a single plane, from an antenna array;

producing an oversampled broadband data stream representing the concurrent plurality of magnetic resonance signals at a rate of at least 1 giga-samples per second; and

processing the oversampled data stream, to generate a matrix of spatial data from the volumetric regions of the object emitting the respective concurrent plurality of the magnetic resonance signals, in dependence on magnetic resonance properties of the object and respective spatial differences in magnetic resonance frequency of the respective concurrent plurality of magnetic resonance signals.

15. The method of claim 14, further comprising:

generating a dynamic magnetic field surrounding the object that varies over time and space, and

producing an image representing magnetic resonance properties of the object in a plane across the object based on the matrix of spatial data.

16. The method of claim 14, wherein the received concurrent plurality of magnetic resonance signals comprise a frequency bandwidth of at least 100 kHz.

17. The method of claim 14, wherein the sampled data stream is generated by at least one sampler comprising at least one superconducting digital flux detector which functions as at least one of a digital superconducting quantum interference device (SQUID) and a superconducting quantum interference filter (SQIF).

18. The method of claim 17, wherein the at least one superconducting digital flux detector comprises a device which operates at a superconducting temperature of below about 20K, and is configured to generate single-flux-quantum (SFQ) pulses.

19. A magnetic resonance imaging system comprising:

a plurality of antennas, located in different positions, configured to each;

receive a plurality of concurrent magnetic resonance emissions from volumetric regions of an object under examination over a range of different magnetic resonance frequencies characteristic of a spatial range of volumetric regions extending beyond a single plane, and

output a broadband electronic signal corresponding to the plurality of concurrent magnetic resonance emissions;

at least one digital detector configured to oversample the broadband electronic signal received from each of the plurality of antennas at a rate of at least 1 giga-samples per second to produce at least one oversampled digital datastream representing the plurality of concurrent magnetic resonance emissions from the respective volumetric regions of the object under examination over the range of different magnetic resonance frequencies characteristic of a spatial range of volumetric regions;

a magnetic field generator configured to generate a magnetic field which varies over time surrounding the object;

at least one processor configured to;

control the magnetic field generator,

receive the oversampled digital datastream, and

generate a matrix of spatial data from the volumetric regions of the object in dependence on magnetic resonance properties of the object and respective magnetic resonance frequencies at respective volumetric regions emitting the concurrent plurality of magnetic resonance emissions; and

at least one memory configured to store the matrix of spatial data.

20. The magnetic resonance imaging system according to claim 19, wherein the at least one processor is further configured to control the magnetic field generator to produce an inhomogeneous magnetic field having vary the magnetic field strengths over time and space, and wherein the plurality of antennas are configured as magnetic gradiometers.