Switchable MRI RF coil array with individual coils having different and overlapping fields of view

Claim 2

An RF MRI receiving coil array comprising: a tuning and matching circuit for connection to an RF transmission line; a first MRI RF receive coil adapted for receiving RF signals from a predetermined NMR species; a second MRI RF receive coil also adapted for receiving RF signals from the same said predetermined species; said first and second MRI RF receive coils having differently dimensioned and overlapping fields of view; and controllable switch means connected with said tuning and matching circuit and with said first and second receive coils and capable of selectively conditioning either one of said coil assemblies for use in receiving RF signals and routing them through said tuning and matching circuit during an MRI procedure.

Claim 3

An RF MRI receiving coil array as in claim 1 wherein each of said coils includes at least one distributed capacitance element serially disposed therealong and said controllable switch means comprises: first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each said switch means.

Claim 4

An RF MRI receiving coil array as in claim 2 wherein: said first and second switch means each include a diode switch; and said first and second control circuits each include an RF trap circuit exhibiting an approximately parallel resonance maximum RF impedance at the MRI RF operating frequency of said coils.

Claim 5

An RF MRI receiving coil array comprising: a first MRI RF receive coil; a second MRI RF receive coil; said first and second MRI RF receive coils having differently dimensioned and overlapping fields of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein said controllable switch means includes manually movable electrical contacts included as a part of an RF circuit within both of said coils.

Claim 6

An RF MRI receiving coil array comprising: a first MRI RF receive coil; a second MRI RF receive coil; said first and second MRI RF receive coils having differently dimensioned and overlapping fields of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein said controllable switch means includes manually movable electrical contacts included as a part of an RF circuit within both of said coils.

Claim 7

An RF MRI receiving coil array comprising: a first MRI RF receive coil adapted for receiving RF signals from said predetermined species; a second MRI RF receive coil also adapted for receiving RF signals from said predetermined species; said first and second MRI RF receive coils having differently dimensioned and overlapping fields of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein each of said coils includes at least one distributed capacitance element serially disposed therealong and said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each said switch means; and wherein each of said switch means is located within its respective coil at a point having an approximately zero RF potential.

Claim 8

An RF MRI receiving coil array comprising: a first MRI RF receive coil adapted for receiving RF signals from said predetermined species; a second MRI RF receive coil also adapted for receiving RF signals from said predetermined species; said first and second MRI RF receive coils having differently dimensioned and overlapping fields of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein each of said coils includes at least one distributed capacitance element serially disposed therealong and said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each said switch means; and wherein each of said switch means is located within its respective coil at a point having an approximately zero RF potential.

Claim 9

An RF receiving coil array comprising: a first MRI RF receive coil; a second MRI RF receive coil; said first and second MRI RF receive coils having differently dimensioned and overlapping field of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein each of said coils includes at least one distributed capacitance element serially disposed therealong and said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each said switch means; wherein said first and second switch means each include a diode switch; said first and second control circuits each include an RF trap circuit exhibiting an approximately parallel resonance maximum RF impedance at the MRI RF operating frequency of said coils; and each of said switch means is located within its respective coil at a point having an approximately zero RF potential.

Claim 10

An RF receiving coil array comprising: a first MRI RF receive coil; a second MRI RF receive coil; said first and second MRI RF receive coils having differently dimensioned and overlapping field of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein each of said coils includes at least one distributed capacitance element serially disposed therealong and said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each said switch means; wherein said first and second switch means each include a diode switch; said first and second control circuits each include an RF trap circuit exhibiting an approximately parallel resonance maximum RF impedance at the MRI RF operating frequency of said coils; and each of said switch means is located within its respective coil at a point having an approximately zero RF potential.

Claim 11

An RF MRI receiving coil array as in claim 6 wherein said first and second control circuits share a common electrical return circuit connected thereto by respectively associated additional parallel RF trap circuits.

Claim 12

An RF MRI receiving coil array comprising: a first MRI RF receive coil; a second MRI RF receive coil; said first and second MRI RF receive coils having differently dimensioned and overlapping fields of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein each of said coils includes at least one distributed capacitance element serially disposed therealong and said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each said switch means; wherein each of said switch means is located within its respective coil at a point of approximately zero RF potential and shares a common dc control current return circuit with an RF circuit.

Claim 13

An RF MRI receiving coil array comprising: a first MRI RF receive coil; a second MRI RF receive coil; said first and second MRI RF receive coils having differently dimensioned and overlapping fields of view; and controllable switch means connected with said first and second receive coils and capable of selectively conditioning either of said coil assemblies for use in receiving RF signals during an MRI procedure; wherein each of said coils includes at least one distributed capacitance element serially disposed therealong and said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each said switch means; wherein each of said switch means is located within its respective coil at a point of approximately zero RF potential and shares a common dc control current return circuit with an RF circuit.

Claim 14

An RF MRI receiver coil array comprising: a first MRI RF receive coil adapted for receiving RF signals from a predetermined NMR species; a second MRI receive coil also adapted for receiving RF signals from the same predetermined NMR species; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common single RF tuning/matching circuit with a common set of adjustable capacitance elements connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure.

Claim 15

An RF MRI receiver coil array comprising: a first MRI RF receive coil adapted for receiving RF signals from a predetermined NMR species; a second MRI receive coil also adapted for receiving RF signals from the same predetermined NMR species; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common single RF tuning/matching circuit with a common set of adjustable capacitance elements connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure.

Claim 16

An RF MRI coil array comprising: a first MRI RF coil; a second MRI RF coil; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common RF tuning/matching circuit connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes manually movable electrical contacts included as a part of an RF circuit within both of said coils.

Claim 17

An RF MRI coil array comprising: a first MRI RF coil; a second MRI RF coil; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common RF tuning/matching circuit connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes manually movable electrical contacts included as a part of an RF circuit within both of said coils.

Claim 18

An RF MRI coil array as in claim 9 wherein said controllable switch means comprises: first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means.

Claim 19

An RF MRI coil array as in claim 11 wherein at least one of said switch means is located within its respective coil at a point having an approximately zero RF potential.

Claim 20

An RF MRI coil array comprising: a first MRI RF coil; a second MRI RF coil; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common RF tuning/matching circuit connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; said first and second switch means each include a diode switch; and said first and second control circuits each include an RF trap circuit exhibiting an approximately parallel resonance maximum RF impedance at the MRI REF operating frequency of said coils.

Claim 21

An RF MRI coil array comprising: a first MRI RF coil; a second MRI RF coil; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common RF tuning/matching circuit connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; said first and second switch means each include a diode switch; and said first and second control circuits each include an RF trap circuit exhibiting an approximately parallel resonance maximum RF impedance at the MRI REF operating frequency of said coils.

Claim 22

An RF MRI coil array as in claim 13 wherein at least one of said switch means is located within its respective coil at a point having an approximately zero RF potential.

Claim 23

An RF MRI coil array as in claim 14 wherein said first and second control circuits share a common electrical return circuit connected thereto by respectively associated additional parallel-resonant RF trap circuits.

Claim 24

An RF MRI coil array comprising: a first MRI RF coil; a second MRI RF coil; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common RF tuning/matching circuit connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; wherein at least one of said switch means is located within its respective coil at a point of approximately zero RF potential and shares a common de control current return circuit with the RF tuning/matching circuit.

Claim 25

An RF MRI coil array comprising: a first MRI RF coil; a second MRI RF coil; said first and second MRI RF coils having differently dimensioned and overlapping fields of view; a common RF tuning/matching circuit connected to both said RF coils and capable of tuning/matching either coil to a predetermined RF impedance; and controllable switch means connected with said first and second coils and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; first electrically operable switch means connected serially with said first coil; second electrically operable switch means connected serially with said second coil; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; wherein at least one of said switch means is located within its respective coil at a point of approximately zero RF potential and shares a common de control current return circuit with the RF tuning/matching circuit.

Claim 26

An RF MRI receive coil array comprising: a first MRI RF receive coil assembly having first distributed capacitance serially connected therealong and presenting a terminal inductance L1; a second MRI RF receive coil assembly having a second distributed capacitance serially distributed therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common single RF tuning and matching circuit having a common set of adjustable capacitance elements connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range LA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure.

Claim 27

An RF MRI receive coil array comprising: a first MRI RF receive coil assembly having first distributed capacitance serially connected therealong and presenting a terminal inductance L1; a second MRI RF receive coil assembly having a second distributed capacitance serially distributed therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common single RF tuning and matching circuit having a common set of adjustable capacitance elements connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range LA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure.

Claim 28

An RF MRI coil array as in claim 17 wherein said controllable switch means comprises: first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with said second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means.

Claim 29

An RF MRI coil array as in claim 18 wherein at least one of said switch means is located within its respective coil assembly at a point having an approximately zero RF potential.

Claim 30

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein each of said coil assemblies includes a surface coil of conductive strip having interruptions in its continuity bridged by capacitance elements.

Claim 31

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein each of said coil assemblies includes a surface coil of conductive strip having interruptions in its continuity bridged by capacitance elements.

Claim 32

An RF MRI coil array as in claim 20, wherein said first coil assembly includes a surface coil having an enclosed area approximately twice the area enclosed by the surface coil of the second coil assembly.

Claim 33

An RF MRI coil array as in claim 21 wherein said first coil assembly encloses an area of approximate dimensions 2L×W while said second coil assembly encloses an area of approximate dimensions L×W approximately centered within said first coil assembly.

Claim 34

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes manually movable electrical contacts included as a part of an RF circuit within both of said coil assemblies.

Claim 35

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes manually movable electrical contacts included as a part of an RF circuit within both of said coil assemblies.

Claim 36

An RF MRI coil array as in claim 23 wherein said controllable switch means comprises: a first fixed contact area connected to said first coil assembly; a second fixed contact area connected to said RF tuning and matching circuit; a third fixed contact area connected to said second coil assembly; and a movable bridge contact area having spring-loaded contact fingers slidable into and out of a bridging RF circuit of contact between said second contact area and either one of said first and third contact areas.

Claim 37

An RF MRI coil array as in claim 24 wherein said controllable switch means comprises: an elongated operating arm mechanically coupled to said movable bridge contact and slidably mounted for movement of same in response to operator movement of the operating arm.

Claim 38

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with said second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; said first and second switch means each include a diode switch; and said first and second control circuits each include an RF trap circuit exhibiting an approximately parallel resonance maximum RF impedance at the MRI RF operating frequency of said coil assemblies. coil assembly at a point having an approximately zero RF potential.

Claim 39

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with said second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; said first and second switch means each include a diode switch; and said first and second control circuits each include an RF trap circuit exhibiting an approximately parallel resonance maximum RF impedance at the MRI RF operating frequency of said coil assemblies. coil assembly at a point having an approximately zero RF potential.

Claim 40

An RF MRI coil array as in claim 26 wherein each said switch means is located within its respective coil assembly at a point having an approximately zero RF potential.

Claim 41

An RF MRI coil array as in claim 27 wherein said first and second control circuits share a common electrical return circuit connected thereto by respectively associated additional RF trap circuits.

Claim 42

An RF MRI coil array as in claim 26 wherein at least one of said switch means is located within its respective coil assembly at a point having an approximately zero RF potential.

Claim 43

An RF MRI coil array as in claim 29 wherein said first and second control circuits share a common electrical return circuit connected thereto by respectively associated additional RF trap circuits.

Claim 44

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with said second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; each said switch means is located within its respective coil assembly at a point having an approximately zero RF potential.

Claim 45

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with said second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; each said switch means is located within its respective coil assembly at a point having an approximately zero RF potential.

Claim 46

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 ad L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with said second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; each said switch means is located within its respective coil assembly at a point of approximately zero RF potential and shares a common dc control current return circuit with the RF tuning and matching circuit.

Claim 47

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning and matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 ad L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with said second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; each said switch means is located within its respective coil assembly at a point of approximately zero RF potential and shares a common dc control current return circuit with the RF tuning and matching circuit.

Claim 48

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning ad matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; at least one of said switch means is located within its respective coil assembly at a point of approximately zero RF potential and shares a common dc control current return circuit with the RF tuning and matching circuit.

Claim 49

An RF MRI coil array comprising: a first MRI RF coil assembly having first distributed capacitance therealong and presenting a terminal inductance L1; a second MRI RF coil assembly having a second distributed capacitance therealong and presenting a terminal inductance L2; said first and second coil assemblies having differently sized but overlapping respective fields of view; a common RF tuning and matching circuit connected to both said first and second coil assemblies and capable of tuning ad matching inductive reactances between a minimum LA and a maximum LB value; said first and second coil assemblies and associated distributed capacitances being dimensioned so as to cause both L1 and L2 to fall within the range KLA to LB; and controllable switch means connected with said first and second coil assemblies and capable of selectively conditioning either one of said coil assemblies for use in an MRI procedure; wherein said controllable switch means includes first electrically operable switch means connected serially with said first coil assembly; second electrically operable switch means connected serially with second coil assembly; and first and second control circuits respectively electrically connected to said first and second switch means to permit selective electrical actuation of each of said switch means; at least one of said switch means is located within its respective coil assembly at a point of approximately zero RF potential and shares a common dc control current return circuit with the RF tuning and matching circuit.

Claim 50

An MRI method comprising the steps of: deriving a first low resolution MRI image of a patient using a first RF receiving coil having a first field of view; switch selecting a second RF receiving coil having a second field of view, which is smaller and overlapping said first field of view, without physically moving said patent; and deriving a second, higher resolution MRI image of said smaller second field of view within said patient without physically moving said patient.

Claim 51

An MRI method comprising the steps of: deriving a first low resolution MRI image of a patient using a first RF receiving coil having a first field of view; switch selecting a second RF receiving coil having a second field of view, which is smaller and overlapping said first field of view, without physically moving said patent; and deriving a second, higher resolution MRI image of said smaller second field of view within said patient without physically moving said patient.