Inductive decoupling of a RF coil array
An apparatus for imaging includes: a radio frequency (RF) coil array having a first RF coil and at least one additional RF coil, where the RF coil array is adapted to generate an image signal; a preamplifier having an input impedance, where the preamplifier is adapted to receive the image signal from the first RF coil; and a transformer to couple the first RF coil to the preamplifier, where impedance of the transformer is adapted to match the input impedance of the preamplifier.
1. An apparatus for imaging, comprising:
a radio frequency (RF) coil array comprising a first RF coil and at least one additional RF coil, the RF coil array adapted to generate an image signal, wherein the first RF coil is inductively decoupled from the at least one additional RF coil;
a preamplifier having an input impedance, the preamplifier adapted to receive the image signal from the first RF coil;
another preamplifier having another input impedance, the other preamplifier adapted to receive the image signal from the at least one additional RF coil;
a first transformer to couple the first RF coil to the preamplifier, impedance of the first transformer to match the input impedance of the preamplifier and
a second transformer to couple the at least one additional RF coil to the other preamplifier, impedance of the second transformer to match the input impedance of the other preamplifier.
2. The apparatus of claim 1 , wherein the first transformer comprises a primary coil coupled to the first RF coil and a secondary coil coupled to the preamplifier.
3. The apparatus of claim 2 , wherein a number of windings for the primary coil of the transformer is one of greater than, fewer than, or equal to a number of windings for the secondary coil of the transformer.
4. The apparatus of claim 1 , wherein the first transformer comprises at least one of helical windings, solenoidal windings, or stripline baluns.
5. The apparatus of claim 1 , wherein the first transformer is a passive transformer.
6. The apparatus of claim 1 , wherein the first transformer comprises an electrostatic shield comprising a conducting material.
7. The apparatus of claim 1 , wherein the first transformer comprises a superconducting material.
8. The apparatus of claim 1 , wherein a ground of the first RF coil is electrically isolated from a ground of the preamplifier.
9. The apparatus of claim 1 , wherein a ground of the first RF coil is electrically isolated from grounds of the additional RF coils in the RF coil array.
10. The apparatus of claim 1 , wherein the apparatus is adapted for magnetic resonance imaging or magnetic resonance spectroscopy.
11. The apparatus of claim 1 , further comprising:
a balun circuit to couple the first RF coil to the first transformer.
12. The apparatus of claim 1 , further comprising:
a coaxial cable with a length equal to one fourth of a wavelength at a frequency of an operation of the first RF coil, to couple the first RF coil to the first transformer.
13. A method for imaging, comprising:
obtaining an image with a radio frequency (RF) coil array comprising a first RF coil and at least one additional RF coil, the first RF coil providing an image signal, wherein the first RF coil is inductively decoupled from the at least one additional RF coil;
passing the image signal from the first RF coil through a first transformer to obtain a first transformed signal;
passing the image signal from the first RF coil through a first transformer to obtain a second transformed signal
matching impedance of the first transformer to an input impedance of a first preamplifier;
amplifying the transformed signal with the first preamplifier;
matching another impedance of the first transformer to an input impedance of a second preamplifier; and
amplifying the transformed signal with the second preamplifier.
14. The method of claim 13 , wherein the first transformer comprises primary and secondary coils and further comprising:
coupling the primary coil to the first RF coil; and
coupling the secondary coil to the preamplifier.
15. The method of claim 13 , further comprising:
coupling the first RF coil to the first transformer via second and third transformers.
16. The method of claim 13 , further comprising:
coupling the first RF coil to the first transformer via a balun circuit.
17. The method of claim 13 , further comprising:
coupling the first RF coil to the first transformer via a coaxial cable with a length equal to one fourth of a wavelength at a frequency of an operation of the first RF coil.
18. An apparatus for imaging, comprising:
a radio frequency (RF) coil array comprising a plurality of RF coils, the RF coil array adapted to generate an image signal, the RF coils being inductively decoupled from each other;
a plurality of preamplifiers, each preamplifier adapted to receive the image signal from a respective RF coil, a ground for each preamplifier being electrically isolated from a ground for each respective RF coil; and
a plurality of transformers, each transformer to couple a different one of the RF coils to a respective preamplifier so that impedance of each transformer matches an input impedance of the respective preamplifier.
19. An apparatus for imaging, comprising:
a radio frequency (RF) coil array comprising a plurality of RF coils, the RF coil array adapted to generate an image signal, the RF coils being inductively decoupled from each other;
a plurality of preamplifiers, each preamplifier adapted to receive the image signal from a respective RF coil, a ground for each preamplifier being electrically isolated from a ground for each respective RF coil; and
a plurality of groups of transformers, each group of transformers to couple one of the RF coils to a respective preamplifier so that an impedance of each group of transformers matches an input impedance of the respective preamplifier.