Unified coil (UNIC) systems and method for next generation magnetic resonance coils

Patent metadata

Field	Value
Publication number	US-11209510-B2
Application number	US-201615763383-A
Country	US
Kind code	B2
Filing date	Nov 3, 2016
Priority date	Nov 6, 2015
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A unified coil assembly for magnetic resonance imaging is disclosed. The coil assembly includes an RF coil element and a shim coil array with a shim coil element. The shim coil element is physically separated or partially separated from the RF coil element. The shim coil element includes a DC current loop having a DC power supply connection to allow DC current to generate a local BO magnetic field. The unified coil array assembly is configured to simultaneously provide an RF mode for at least one of transmit or receive and a direct current mode to generate a local B0 magnetic field for B0 shimming Larger number of shim coils relative to the RF coil element provides superior shimming performance. The mutual inductance between the shim coil element and the RF coil element is minimized by proposed geometrical decoupling methods in order to minimize the RF interaction between the two.

First claim

What is claimed is:

1. A Magnetic Resonance Imaging (MRI) system, comprising:
a unified coil array system including:
a radio frequency (RF) coil array including a plurality of RF coil elements, the RF coil array being configured to operate operative in an RF mode for at least one of transmit or receive; and
a separate shim coil array having a plurality of shim coil elements configured to operate in a direct current (DC) mode with direct current flow in the plurality of shim coil elements to generate one or more local B0 magnetic fields, the separate shim coil array being configured to operate independently from and simultaneously with the RF coil array to generate the one or more local B0 magnetic fields, the plurality of shim coil elements being physically separated from the plurality of RF coil elements,
wherein each respective one of the plurality of RF coil elements in the RF coil array is associated with a respective 2N shim coil elements of the separate shim coil array,
wherein at least part of each respective one of the plurality of RF coil elements overlaps with at least part of the respective 2N shim coil elements associated with the respective one of the plurality of RF coil elements,
wherein each respective one of the plurality of RF coil elements is geometrically decoupled from the respective 2N shim coil elements associated with the respective one of the plurality of RF coil elements, and
wherein each of the plurality of shim coil elements is physically arranged relative to each of the plurality of RF coil elements such that a mutual inductance between the plurality of shim coil elements and the plurality of RF coil elements is minimized or zero, thereby geometrically decoupling the plurality of shim coil elements from the plurality of RF coil elements;
a magnet bore of a MRI scanner holding a target object, the RF coil element and the separate shim coil array positioned about the target object;
a DC power supply in communication with the separate shim coil array to supply direct current to the at least one shim coil element of the separate shim coil array;
a shim coil circuit in communication with the separate shim coil array configured to direct the DC power supply to supply the direct current to the at least one shim coil element to generate the one or more local BO magnetic fields; and
an RF circuit in communication with the RF coil element configured to receive an MR signal from the object for RF receive or transmit RF pulses to the object for RF transmit.

2. The system of claim 1 , wherein a first one of the respective 2N shim coil elements has a magnetic flux of one polarity resulting from undesirable RF currents induced by the respective RF coil element, and a second one of the respective 2N shim coil elements has an opposite polarity induced by the same RF coil element.

3. The system of claim 1 , wherein the 2N shim coil elements of each of the at least one of the plurality of RF coil elements are identical in size and shape, and at least two of the 2N shim coil elements are sequentially connected though a pair of DC blocking capacitors.

4. The system of claim 1 , wherein the DC power source includes 2N channels, each of the channels corresponding to one of the plurality of shim coil elements and wherein the shim coil circuit allows individual adjustment of each direct current in each of the plurality of shim coil elements.

5. The system of claim 1 , wherein at least one of the shim coil elements is a multiple-turn loop.

6. The system of claim 1 , wherein the RF coil array is one of a receive-only RF coil array, a transmit-only RF coil array, or a transmit/receive RF coil array.

7. The system of claim 1 , wherein the shape of at least one of the plurality of shim coil elements and at least one of the plurality of RF coil elements is a closed curve, a polygon, a circular shape, a square shape, a rectangular shape, a diamond shape, or a triangular shape.

8. The system of claim 1 , wherein the unified coil array system is one of a head coil, a head neck spine coil, a cardiac coil, a body coil, a torso coil, a breast coil, a musculoskeletal coil, a knee coil, a foot/ankle coil, a carotid coil, a wrist coil, a Cervical/Thoracic/Lumbar coil.

9. The system of claim 1 , wherein the MRI system images non-tissue material.

10. The system of claim 1 , wherein the MM scanner is one of a human scanner, an animal scanner, a material MR system, or a NMR spectrometer.

11. The system of claim 1 , wherein the unified coil array system includes a plurality of closely stacked layers of individually operable discrete RF coil elements of the RF coil array and shim coil elements of the separate shim coil array.

12. The system of claim 1 , wherein the shim coil circuit is configured to use the generated one or more local B0 magnetic fields to perform B0 shimming.

13. The system of claim 1 , wherein the shim coil circuit is configured to control the direct current in the at least one coil element of the separate shim coil array and measure the generated one or more local B0 magnetic fields.

14. The system of claim 1 , wherein the shim coil circuit is in communication with an MR scanner, and wherein the at least one shim coil element in the separate shim coil array comprise at least one loop for direct current from the DC power supply, wherein the at least one loop includes an inductor.

15. The system of claim 1 , wherein the RF coil array is a single transmit and receive RF coil array, and wherein the RF circuit is in communication with an MR scanner to cause the RF coil array to transmit and receive while causing the separate shim coil array to shim a main B0 field inhomogeneity using the generated one or more local B0 magnetic fields from the shim coil array.

16. The system of claim 1 , wherein the separate shim coil array is configured to generate the one or more local B0 magnetic fields to provide a uniform B0 magnetic field across the target object.

17. The system of claim 1 , wherein at least one of the plurality of RF coil elements shares at least one physical conductor with its associated 2N shim coil elements.

18. The system of claim 1 , wherein the generated one or more local B0 magnetic fields are configured to be used for B0 shimming.

19. The system of claim 1 , wherein the at least one shim coil element includes at least one circuit component having a resonant frequency that is generally equal to a Larmor frequency of the MRI system or within 10% of the Larmor frequency of the MRI system, the at least one circuit component including an inductor in parallel with a capacitor.

20. The system of claim 1 , wherein a ratio of (i) an overlap distance between at least one of the plurality of RF coil elements and the respective 2N shim coil elements associated with the at least one of the plurality of RF coil elements to (ii) a diameter of its associated 2N shim coil elements is between about 0% and about 75%.

21. The system of claim 1 , wherein the respective 2N shim coil elements associated with one of the plurality of RF coil elements includes a first shim coil element and a second shim coil element, the first shim coil element and the second shim coil element overlapping with each other, the first shim coil element and the second shim coil element both extending partially outside of the one of the plurality of RF coil elements.

22. The system of claim 1 , wherein the respective 2N shim coil elements associated with one of the plurality of RF coil elements includes a first sh

Assignees

• Cedars Sinai Medical Center

Inventors

• Han Hui
• Li Debiao

Classifications

• A61B5/055

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

• G01R33/341

  comprising surface coils · CPC title

• G01R33/3415

  comprising arrays of sub-coils {, i.e. phased-array coils with flexible receiver channels} · CPC title

• A61B5/4566

  Evaluating the spine (A61B5/4561 takes precedence) · CPC title

• G01R33/34046

  Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils · CPC title