Quadrature surface coil array

• US 5,198,768 A
• Filed: 09/25/1990
• Issued: 03/30/1993
• Est. Priority Date: 09/27/1989
• Status: Expired due to Fees

• Current Assignee: GE Medical Systems Israel, Ltd
• Original Assignee: Elscint Limited (Elbit Imaging Limited)
• Inventors: Keren, Hanan
• Primary Examiner(s): ARANA, LOUIS M
• Application Number:
  US07/587,447
• Time in Patent Office: 917 Days
• Field of Search: 324/300, 324/307, 324/309, 324/318, 324/322, 128/653 SC
• US Class Current: 324/318
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/3678 involving quadrature drive or detection, e.g. a circularly polarized RF magnetic field

Abstract

A quadrature surface coil array comprising a plurality of single loop surface coils interspersed with a plurality of adjacent double loop surface coils, at least some of said surface coils overlapping the ends of adjacent surface coils and said double loop surface coils having the two loops in series to support only a single current mode thereby inhibiting cross coupling including next nearest neighbor cross coupling.

Claims

1. A surface coil array comprising:

a plurality of adjacent surface coils,

said array extending in a first direction,

said surface coils including;

single loop surface coils,

double loop surface coils,

means for inhibiting cross-coupling between nearest neighbor coils,

means for inhibiting cross-coupling between next nearest neighbor coils,

said means for inhibiting cross-coupling between nearest neighbor surface coils comprising overlapping the ends in said first direction of said adjacent ones of said surface coils,

said means for inhibiting cross-coupling between next nearest neighbor surface coils comprising said double loop surface coils wherein the two loops of said double loop surface coils are in series so as to support only a single current mode.

2. A surface coil array comprising:

at least four adjacent surface coils extending in a first direction,

a first of said four surface coils being a single loop surface coil,

a second and third surface coil being two-loop surface coils said loops support only a single current mode to inhibit cross-coupling including next nearest neighbor cross-coupling,

said fourth surface coil being a single loop surface coil, and

all of said surface coils overlapping the adjacent surface coil in said first direction to inhibit nearest neighbor cross-coupling.

3. The surface coil array of claim 2 wherein said single loop surface coils are rectangularly shaped surface coils.

4. The surface coil array of claim 2 wherein the two loops of the two loop surface coils extend in a direction normal to the longitudinal direction of the array.

5. The surface coil array of claim 2 wherein the two loops are each overlapped by the preceding coil.

6. A quadrature surface coil arrangment for use in magnetic resonance (MR) systems, said surface coil arrangement comprising:

a first coil for generating a circular magnetic field responsive to currents generated in the first coil means by free induction decay (FID) signals in the MR system,

a second coil proximate to said first coil,

said first coil extending beyond said second coil in a first direction and said second coil extending beyond said first coil in a second direction orthogonal to said first direction,

said second coil producing a magnetic field lying normal to the plane of the second coil at the center of the second coil responsive to FID signals in the MR system, and

said first coil being a cross-coupling inhibiting coil comprising a first loop and a second loop, and

means for electrically coupling said first and second loop in series to inhibit cross-coupling between the first loop and the second loop.

7. The quadrature surface coil arrangment of claim 6 wherein said second coil means comprises a single loop.

8. The quadrature surface coil arrangment of claim 7 including:

means for coupling said quadrature surface coil to said MR system,

said means for coupling to said MR system comprising;

hybrid combiner means,

coaxial cable means for coupling said quadrature surface coil to said hybrid combiner means.

9. The quadrature surface coil arrangment of claim 7 wherein said coaxial cable means comprises:

first and second coaxial cables,

one of said first and second coaxial cable means including a quarter wavelength section whereby one of said coaxial cables is longer than the other of said first and second coaxial cables by approximately a quarter wavelength.