Phased array RF coil for magnetic resonance imaging

Patent metadata

Field	Value
Publication number	US-9709645-B2
Application number	US-201314075455-A
Country	US
Kind code	B2
Filing date	Nov 8, 2013
Priority date	Nov 8, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A phased array radio-frequency (RF) coil includes a cylindrical frame including a coaxial inner frame and a coaxial outer frame having different diameters; and vertical loop coils arranged in a circumferential direction of the cylindrical frame. Each vertical loop coil includes an inner conductor extending in a lengthwise direction on the coaxial inner frame; an outer conductor extending in a lengthwise direction on the coaxial outer frame and facing the inner conductor; and a first resonant frequency adjustment capacitor for connecting one end of the inner conductor in the lengthwise direction and one end of the outer conductor in the lengthwise direction so that the phased array RF coil resonates at an MR operating frequency.

First claim

What is claimed is:

1. A phased array radio-frequency (RF) coil for magnetic resonance imaging (MRI), the phased array RF coil comprising:
a cylindrical frame including a coaxial inner frame and a coaxial outer frame having different diameters and extending between a first end of the cylindrical frame and a second end of the cylindrical frame in a lengthwise direction; and
vertical loop coils arranged in a circumferential direction of the cylindrical frame, wherein each vertical loop coil comprises:
an inner conductor extending on the coaxial inner frame in the lengthwise direction between the first and second ends of the cylindrical frame;
an outer conductor extending on the coaxial outer frame in the lengthwise direction between the first and second ends of the cylindrical frame and facing the inner conductor;
a first resonant frequency adjustment capacitor which connects one end of the inner conductor and one end of the outer conductor at the first end of the cylindrical frame; and
a second resonant frequency adjustment capacitor which connects another end of the inner conductor and another end of the outer conductor at the second end of the cylindrical frame,
wherein the first resonant frequency adjustment capacitor, the inner conductor, the second resonant frequency adjustment capacitor, and the outer conductor are connected to one another to form an electrical loop, and
the first resonant frequency adjustment capacitor and the second resonant frequency adjustment capacitor cooperate so that the phased array RF coil resonates at an MR operating frequency.

2. The phased array RF coil of claim 1 , wherein the inner conductor comprises inner sub conductors disposed along the lengthwise direction, and the phased array RF coil further comprises:
a third resonant frequency adjustment capacitor which is connected between each pair of the inner sub conductors in the lengthwise direction.

3. The phased array RF coil of claim 2 , wherein the outer conductor comprises outer sub conductors disposed along the lengthwise direction, and the phased array RF coil further comprises:
a fourth resonant frequency adjustment capacitor which is connected between each pair of the outer sub conductors in the lengthwise direction.

4. The phased array RF coil of claim 3 , wherein a number of the inner sub conductors is equal to a number of the outer sub conductors.

5. The phased array RF coil of claim 3 , further comprising:
decoupling capacitors which are connected between adjacent vertical loop coils to independently drive each of the vertical loop coils.

6. The phased array RF coil of claim 1 , wherein the outer conductor comprises outer sub conductors disposed along the lengthwise direction, the phased array RF coil further comprises:
a fourth resonant frequency adjustment capacitor which is connected between each pair of the outer sub conductors.

7. The phased array RF coil of claim 1 , wherein the vertical loop coils are disposed at isogonal intervals along a circumference of the cylindrical frame.

8. The phased array RF coil of claim 1 , wherein the inner conductor is a conductor plate, of which a portion is removed.

9. The phased array RF coil of claim 1 , wherein a width of the outer conductor in the circumferential direction of the outer frame is greater than a width of the inner conductor in the circumferential direction of the inner frame.

10. The phased array RF coil of claim 1 , wherein the inner conductor is a conductor plate that has a curved surface and is bent along a circumference of the inner frame.

11. The phased array RF coil of claim 10 , wherein the outer conductor is a conductor plate that has a curved surface and is bent along a circumference of the outer frame.

12. The phased array RF coil of claim 11 , wherein a central angle of the outer conductor is greater than a central angle of the inner conductor, with respect to a central axis on the cylindrical frame.

13. The phased array RF coil of claim 1 , wherein the outer conductor comprises:
an insulating layer; and
outer conductor plate pieces which are arranged on both sides of the insulating layer, to partially overlap, as viewed in a cross-sectional direction of the insulating layer.

14. The phased array RF coil of claim 13 , wherein the outer conductor plate pieces comprise:
first outer conductor plate pieces disposed at an inner side of the insulating layer and second outer conductor plate pieces disposed at an outer side of the insulating layer,
wherein the insulating layer is disposed between the first outer conductor plate pieces and the second outer conductor plate pieces.

15. The phased array RF coil of claim 13 , wherein the insulating layer comprises insulating layer pieces,
each of the outer conductor plate pieces comprises a first side and a second side opposing the first side,
the outer conductor plate pieces are arranged such that a first side of one of the outer conductor plate pieces is disposed below a second side of an adjacent one of the outer conductor plate pieces, along a circumference of the outer frame, and
the insulating layer pieces are respectively inserted into regions which are disposed between overlapping outer conductor plate pieces.

16. The phased array RF coil of claim 1 , further comprising:
decoupling capacitors which are disposed between each pair of the vertical loop coils to independently drive each of the vertical loop coils.

17. A radio-frequency system for magnetic resonance imaging (MRI), the system comprising:
a phased array radio-frequency (RF) coil including a cylindrical frame including a coaxial inner frame and a coaxial outer frame having different diameters and extending between a first end of the cylindrical frame and a second end of the cylindrical frame in a lengthwise direction, and vertical loop coils arranged in a circumferential direction of the cylindrical frame; and
a controller configured to drive the phased array RF coil, wherein each vertical loop coil comprises:
an inner conductor extending on the coaxial inner frame, in the lengthwise direction between the first and second ends of the cylindrical frame;
an outer conductor extending on the coaxial outer frame in the lengthwise direction between the first and second ends of the cylindrical frame and facing the inner conductor;
a first resonant frequency adjustment capacitor which connects one end of the inner conductor and one end of the outer conductor at the first end of the cylindrical frame; and
a second resonant frequency adjustment capacitor which connects another end of the inner conductor and another end of the outer conductor at the second end of the cylindrical frame,
wherein the first resonant frequency adjustment capacitor, the inner conductor, the second resonant frequency adjustment capacitor, and the outer conductor are connected to one another to form an electrical loop, and
the first resonant frequency adjustment capacitor and the second resonant frequency adjustment capacitor cooperate
so that the phased array RF coil resonates at an MR operating frequency.

18. The radio-frequency system of claim 17 , wherein the controller comprises RF power amplifiers connected to the vertical loop coils.

19. The radio-frequency system of claim 18 , wherein a number of the RF power amplifiers is equal to a number of the vertical loop coils.

20. The radio-frequency system of claim 18 , wherein the controller further comprises:
a power divider configured to divide RF power output from the RF power amplifiers i

Assignees

• Samsung Electronics Co Ltd
• Ind Acad Coop Found Kyunghee Univ

Inventors

• Lee Ju-Hyung
• Lee Soo-Yeol

Classifications

• G01R33/3415 Primary

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

• G01R33/34007

  Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system · CPC title

• G01R33/5659

  caused by a distortion of the RF magnetic field, e.g. spatial inhomogeneities of the RF magnetic field (G01R33/56509, G01R33/56518, G01R33/56536 take precedence) · CPC title

• G01R33/3628

  Tuning/matching of the transmit/receive coil · CPC title

• G01R33/3453

  Transverse electromagnetic [TEM] coils · CPC title