Split-top, neck and head vascular array for magnetic resonance imaging

In a magnetic resonance apparatus which includes a magnet for generating a temporally constant, uniform magnetic field through an examination region, at least one radio frequency coil which performs at least one of (1) transmitting radio frequency signals into the examination region to induce and manipulate resonance of dipoles disposed therein and (2) receiving radio frequency signals from resonating poles in the examination region, and a processor for processing the received magnetic resonance signals, the radio frequency coil including

• a first coil assembly, the first coil assembly including a birdcage style coil and further including a guard ring disposed adjacent the birdcage style coil;
• a first electronic circuit mounted adjacent to and connected with the second coil assembly;
• a first coaxial cable extending from the first electronic circuit past and contiguous to the first coil assembly, to a region on an opposite side of the first coil assembly;
• second coil assembly disposed contiguous to and only partially overlapping the first coil assembly in a common overlap region;
• a second electronic circuit disposed adjacent to and contiguous with the second coil;
• a second coaxial cable extending from the second coil past and contiguous to the first coil assembly to the opposite side thereof, sheaths of the first and second coaxial cables being electrically connected with the guard ring;
• and
• a first coil-to-coil decoupling circuit connected with the first coaxial cable for inhibiting the first and second coil assemblies from coupling along the first coaxial cable, the first coil-to-coil decoupling circuit being disposed on an opposite side of the guard ring from the birdcage style coil.

In a magnetic resonance apparatus which includes a magnet for generating a temporally constant, uniform magnetic field through an examination region, a radio frequency coil which performs at least one of (1) transmitting radio frequency signals into the examination region to induce and manipulate resonance of dipoles disposed therein and (2) receiving radio frequency signals from resonating dipoles in the examination region, and a processor for processing the received magnetic resonance signals, the radio frequency coil including:

• a first coil assembly;
• a first electronic circuit mounted adjacent to and connected with the second coil assembly;
• a first coaxial cable extending from the first electronic circuit past and contiguous to the first coil assembly;
• a second coil assembly disposed contiguous to and partially overlapping the first coil assembly in a common overlap region, including a first coil connected with the first coaxial cable and a second coil;
• a second electronic circuit disposed adjacent to and contiguous with the second coil;
• a second coaxial cable extending from the second coil past and contiguous to the first coil assembly to an opposite side thereof;
• a first coil-to-coil decoupling circuit connected with the first coaxial cable for inhibiting the first and second coil assemblies from coupling along the first coaxial cable;
• a second coil-to-coil decoupling circuit connected with the second coaxial cable for inhibiting the second coil and the first coil assembly from coupling along the second coaxial cable;
• a lower housing portion which supports the second coil, a lower part of the first coil assembly, the second electronic circuit, and the second decoupling circuit;
• an upper housing portion which supports the first coil, an upper part of the first coil assembly, the first electronic circuit, and the first decoupling circuit, the upper and lower housing portions being selectively mechanically couplable to provide a unitary coil construction and decouplable to facilitate patient access;
• and,
• electrical connections for interconnecting the upper and lower parts of the first coil assembly.

In a magnetic resonance apparatus which includes a magnet for generating a temporally constant, uniform magnetic field through an examination region, a radio frequency coil which performs at least one of (1) transmitting radio frequency signals into the examination region to induce and manipulate resonance of dipoles disposed therein and (2) receiving radio frequency signals from resonating dipoles in the examination region, and a processor for processing the received magnetic resonance signals, the radio frequency coil including:

• a first volume coil assembly;
• a second volume coil assembly disposed contiguous to and partially overlapping the first coil assembly in a common overlap region;
• an electronic circuit mounted adjacent to and connected with the second coil assembly;
• a coaxial cable extending from the first electronic circuit past and contiguous to the first coil assembly, to a region on an opposite side of the first coil assembly from the second coil assembly;
• a coil-to-coil decoupling circuit connected with the first coaxial cable for inhibiting the first and second coil assemblies from coupling along the first coaxial cable, the coil-to-coil decoupling circuit including:
• a case having a spool-like construction therein, the case having coaxial cable receiving guides for receiving the coaxial cable and locking the coaxial cable against longitudinal movement, the coaxial cable being wrapped around the spool to form an inductance and being interconnected with at least one adjustable tuning capacitor;
• an electrically conductive layer for coating and shielding the case.

In a magnetic resonance apparatus which includes a magnet for generating a temporally constant, uniform magnetic field through an examination region, a radio frequency coil which performs at least one of (1) transmitting radio frequency signals into the examination region to induce and manipulate resonance of dipoles disposed therein and (2) receiving radio frequency signals from resonating dipoles in the examination region, and a processor for processing the received magnetic resonance signals, the radio frequency coil including:

• a first coil assembly, the first coil assembly being at least four-fold symmetric;
• a second coil assembly disposed contiguous to and partially overlapping the first coil assembly in a common overlap region, the second coil assembly being at least two-fold symmetric;
• an electronic circuit mounted adjacent to and connected with the second coil assembly;
• a coaxial lead extending from the electronic circuit past and contiguous to the first coil assembly, to a region on an opposite side of the first coil assembly from the second coil assembly;
• a coil-to-coil decoupling circuit connected with the coaxial lead for inhibiting the first and second coil assemblies from coupling along the first coaxial lead.

A radio frequency coil for at least receiving magnetic resonance signals, the radio frequency coil comprising:

• a first volume coil assembly;
• a second volume coil assembly disposed contiguous to and partially overlapping the first volume coil assembly in an overlap region;
• a coaxial lead extending from the second volume coil assembly, along the first volume coil assembly, to a region on an opposite side of the first volume coil assembly from the second volume coil assembly;
• a coil-to-coil decoupling circuit connected with the coaxial lead for inhibiting the first and second volume coil assemblies from coupling to each other along the coaxial cable while receiving the magnetic resonance signals such that cross-talk between the first and second volume coil assemblies is inhibited.

A radio frequency coil for at least receiving magnetic resonance signals, the radio frequency coil comprising:

• a first coil assembly, the first coil assembly being at least four-fold symmetric;
• a second coil assembly disposed contiguous to and partially overlapping the first coil assembly in an overlap region, the second coil assembly being at least two-fold symmetric;
• a coaxial lead extending from the second coil assembly, along the first coil assembly, to a region on an opposite side of the first coil assembly from the second coil assembly;
• a coil-to-coil decoupling circuit connected with the coaxial cable for inhibiting the first and second coil assemblies from coupling along the coaxial cable.

A radio frequency coil for at least receiving magnetic resonance signals, the radio frequency coil comprising:

• a first coil assembly, the first coil assembly including a birdcage coil and a guard ring;
• a second coil assembly disposed contiguous to and partially overlapping the birdcage coil in an overlap region, the guard ring disposed adjacent;
• a first coaxial cable extending from the second coil assembly, along the birdcage coil, to a region on an opposite side of the birdcage coil from the second coil assembly, a sheath of the first coaxial cable being electrically connected with the guard ring;
• a first coil-to-coil decoupling circuit connected with the first coaxial cable for inhibiting the birdcage coil and the second volume coil assembly from coupling along the first coaxial cable.

A radio frequency coil for receiving magnetic resonance signals, the radio frequency coil comprising:

• a first coil assembly;
• a second coil assembly disposed contiguous to and partially overlapping the first coil assembly in an overlap region;
• a coaxial lead extending from the second coil assembly, along the first coil assembly, to a region on an opposite side of the first coil assembly from the second coil assembly;
• a coil-to-coil decoupling circuit connected with the first coaxial cable for inhibiting the first and second coil assemblies from coupling along the coaxial cable, the first decoupling circuit including:
• a housing having a spool-like cable guide therein, the housing having first and second coaxial cable receiving shoulders for receiving the coaxial cable and locking the coaxial cable against longitudinal movement, the coaxial cable being looped around the cable guide to form an inductance and being interconnected with at least one tuning capacitor;
• an electrically conductive radio frequency shield which shields the housing.

In a method of magnetic resonance imaging in which a temporally constant uniform magnetic field is generated through a head and neck examination region, magnetic field gradients are applied across the examination region, radio frequency signals are transmitted into the examination region to induce and manipulate magnetic resonance of dipoles therein, radio frequency signals are received from the resonating dipoles with a radio frequency coil assembly that has a first coil assembly around the head region and a second coil assembly around the neck region, and the received radio frequency signals are processed into an image representation, the improvement comprising:

• receiving magnetic resonance signals from resonating dipoles in at least one of the head and neck regions with corresponding first and second volume coil assemblies;
• passing signals received by one of the first and second volume coil assemblies through a cable which extends along the other volume coil assembly for processing into the volumetric image representation;
• passing signals received from the other volume coil assembly along a second cable for processing into the volumetric image representation;
• preventing the first and second volume coil assemblies from coupling to each other along the first cable;
• generating the volumetric image representation of at least one of the head and neck regions from the signals passed along the first and second cables.

A magnetic resonance method comprising:

• tuning a birdcage coil which is mounted on a dielectric former to a magnetic resonance frequency;
• tuning neck coils that are mounted on dielectric formers to the magnetic resonance frequency;
• overlapping the birdcage and neck coils and adjusting the overlap until a preselected degree of mutual coupling is achieved;
• fixing the dielectric formers of the birdcage and neck coils in the overlapped position;
• retuning the birdcage coil and the neck coils, as necessary, in a single iteration;
• and,
• mounting outer housings around the neck and birdcage coils.