Abstract: An example magnetic resonance imaging (MRI) radio frequency (RF) coil array comprises: at least one row of RF coil elements arranged radially around a cylindrical axis, wherein each row comprises: at least four RF coil elements circumferentially enclosing the cylindrical axis, wherein each RF coil element of that row is configured to operate in a Tx mode and in a Rx mode, wherein, in the Rx mode, each RF coil element of that row is tuned to a working frequency of the MRI RF coil array, and wherein, in the Tx mode, each RF coil element of that row is tuned to an additional frequency that is different than the working frequency, wherein the additional frequency is such that, a mode frequency of a selected mode resulting from coupling among the RF coil elements of that row is at the working frequency.

Abstract: Methods and other embodiments control a member of a plurality of MRI transmit (Tx)/receive (Rx) coil array elements to operate in a resonant Tx mode or in a non-resonant Tx mode. The member of the plurality of MRI Tx/Rx coil array elements, upon resonating with a primary coil at a working frequency, generates a local amplified Tx field based on an induced current in the member of the plurality of MRI Tx/Rx coil array elements. The member of the plurality of MRI Tx/Rx coil array elements includes at least one magnitude/phase control circuit connected in parallel. Upon detecting that the member of the plurality of MRI Tx/Rx coil array elements is operating in resonant Tx mode, embodiments randomly control a member of the at least one magnitude/phase control circuit to vary the magnitude or phase of the local amplified Tx field over a range of magnitudes or phases.

Abstract: An MRI RF coil array for use in a multi-channel MRI system, comprising a plurality of coils arranged in a M by N array, the number of columns corresponding with the number of channels in the MRI system. Columns are aligned with the B0 field. The plurality of coils are configured as a plurality of combined coils, corresponding with the number of columns, comprising a coil in a first row of the array connected with a coil in each of the remaining rows. The column position of each coil of a combined coil is distinct from the column position of each other coil of the combined coil. Coils of a combined coil are disjoint from the coils of each, other, combined coil. A combined coil is configured to connect with a corresponding member of the plurality of Rx channels, and is decoupled from each, other combined coil.

Abstract: Example magnetic resonance imaging (MRI) radio frequency (RF) coils employ flexible coaxial cable. An MRI RF coil may include an LC circuit and an integrated decoupling circuit. The LC circuit includes one or more flexible coaxial cables having a first end and a second end, the one or more flexible coaxial cables having an inner conductor, an outer conductor, and a dielectric spacer disposed between the inner conductor and the outer conductor, where the outer conductor of the coaxial cable is not continuous between the first end and the second end at a first location. The integrated decoupling circuit may include a PIN diode and a tunable element. The tunable element may be tunable with respect to resistance, capacitance, or inductance, and thus may control, at least in part, the frequency at which the LC circuit resonates during RF transmission, or an impedance at the first location.

Abstract: Embodiments relate to magnetic resonance imaging (MRI) radio frequency (RF) coil arrays having reduced coupling via hidden transmission lines. One example embodiment comprises a MRI RF coil array comprising: a first RF coil element coupled to a first output transmission cable (e.g., coaxial) that is configured to carry a first signal that is associated with the first RF coil element; a second RF coil element coupled to a second output transmission cable that is configured to carry a second signal that is associated with the second RF coil element, wherein the second RF coil element comprises a first portion of the first output transmission cable; and a first balun configured to reduce coupling associated with the first signal, wherein the first balun is arranged between the first RF coil element and the second RF coil element. Additional coil elements can be similarly combined in embodiments.

Abstract: A single-layer magnetic resonance imaging (MRI) radio frequency (RF) coil array configured to operate in a transmit (Tx) mode or in a receive (Rx) mode comprises at least one single-layer MRI RF coil array element configured to provide integrated B0 field shimming. The at least one single-layer MRI RF coil array element includes a resonant LC coil, a matching Tx/Rx switch circuit, a magnitude/phase control component, and a preamplifier. The LC coil, upon resonating with a primary coil at the working frequency, generates a local amplified Tx field based on an induced current in the LC coil. The magnitude/phase control component is configured to independently adjust a magnitude or a phase of the induced current. The at least one single-layer MRI RF coil element may include a Tx field monitoring component configured to monitor the strength or phase of the local amplified Tx field.

Abstract: Example embodiments include a radio frequency (RF) transmit system for a digital RF current source, the system including a magnetic resonance imaging (MRI) system control console operably connected to at least one digital RF current source amplifier. The at least one digital RF current source amplifier is operably connected to an RF transmission coil. The MRI system control console provides a digital control signal to the at least one digital RF current source amplifier. The MRI system control console provides a master RF current source clock signal to the at least one digital RF current source amplifier. The digital RF current source amplifier provides an alternating current to the RF transmission coil.

Abstract: An example magnetic resonance imaging (MRI) coil base apparatus for use with interchangeable attachable and detachable coil attachments is described. The coil base apparatus electrically and mechanically couples to different MRI coil attachments designed for imaging different body parts (e.g., ankles, knees, wrists, elbows, shoulders). The MRI coil base apparatus includes elements (e.g., channel, pre-amplifier, mixer, feed circuit, decoupling circuit) for controlling the coil attachment to transmit radio frequency (RF) energy that produces nuclear magnetic resonance (NMR) in an object exposed to the RF energy. The coil attachment includes elements that transmit the RF energy and a copper trace that receives resulting NMR signals. The coil base apparatus may include a slide apparatus for repositioning the coil attachment in one axis when the coil attachment is coupled to the coil base apparatus or a pivot apparatus for rotating the coil attachment when it is coupled to the coil base apparatus.

Abstract: A magnetic resonance imaging (MRI) radio frequency (RF) coil array configured to operate in a transmit (Tx) mode or in a receive (Rx) mode, the MRI RF coil array comprising at least one single-layer RF coil element. The at least one RF coil element includes a resonant LC coil, a matching Tx/Rx switch circuit, and a preamplifier. The matching and Tx/Rx switch circuit, when operating in Tx mode, electrically isolates the LC coil from the preamplifier upon the LC coil resonating with a primary coil at the primary coil's working frequency. The LC coil, upon resonating with the primary coil at the working frequency, generates a local amplified Tx field based on an induced current in the LC coil. A magnitude or a phase of the induced current is independently adjustable. The matching and Tx/Rx switch circuit, when in Rx mode, electrically connects the LC coil with the preamplifier.

Abstract: In order to provide interventional access during an image-guided interventional procedure, while increasing the signal-to-noise ratio for generated images compared to a single loop coil, a local coil includes a single coil element disposed around an opening through the local coil and two coil elements positioned on opposite sides of the single coil element. The opening provides access for an interventional tool used during the image-guided interventional procedure.

Abstract: Example apparatus and magnetic resonance imaging (MRI) radio frequency (RF) coils concern controlling current magnitude at different sections in one MRI RF coil. In one embodiment, an MRI RF coil comprises a plurality of loop coils configured to transmit or receive an RF signal. A member of the plurality of loop coils comprises an inductor and at least one capacitor. The MRI RF coil further comprises at least one coaxial transmission line that electrically couple in series a first member of the plurality of loop coils with a second, different member of the plurality of loop coils. The at least one coaxial transmission line has a length that is one-quarter wavelength (?/4) of the RF signal, or an odd integer multiple of ?/4 of the RF signal.

Abstract: A magnetic resonance imaging (MRI) radio frequency (RF) coil comprising an LC circuit including at least one series capacitor, and a decoupling circuit connected in parallel to the LC circuit. The decoupling circuit is configured to decouple the MRI RF coil from one or more other MRI RF coils using passive decoupling upon the production of an induced voltage in the decoupling circuit, or to actively decouple the MRI RF coil from one or more other MRI RF coils upon the insertion of a DC bias into the decoupling circuit. The decoupling circuit includes a pair of fast switching PIN diodes including a first PIN diode connected antiparallel with a second PIN diode, the second PIN diode connected in series with a first capacitor. The decoupling circuit further includes an inductor connected in series with the pair of fast switching PIN diodes and the capacitor.

Abstract: Apparatus associated with improved magnetic resonance imaging (MRI) guided needle biopsy procedures (e.g., breast needle biopsy) are described. One example apparatus includes a support structure configured to support a patient in a face-down prone position where a breast of the patient is positioned in a first free hanging pre-imaging position. The example apparatus includes an immobilization structure configured to reposition the breast into an immobilized position suitable for MRI and for medical instrument access. The immobilization structure may include a removable biopsy plate, a removable side coil, a pressure plate, and MRI coils. The MRI coils are configured to be repositioned from a first position associated with the free hanging pre-imaging position to a second position associated with the immobilized position to facilitate improving the signal to noise ratio associated with signal received from the breast through the MRI coils.

Abstract: Example magnetic resonance imaging (MRI) radio frequency (RF) coils are described. An MRI RF coil may include an LC circuit and an integrated decoupling circuit. The integrated decoupling circuit may include a wire or other conductor that is connected to the LC circuit and that is positioned within a defined distance of the LC circuit. The integrated decoupling circuit may include a PIN diode and a tunable element. The tunable element may be tunable with respect to resistance, capacitance, or inductance, and thus may control, at least in part, the frequency at which the LC circuit resonates during RF transmission. The example MRI RF coil has more than one point of high impedance, which facilitates reducing heating and operational issues associated with conventional coils.

Abstract: Example magnetic resonance imaging (MRI) radio frequency (RF) coils are described. An MRI RF coil may include a first terminal and a second terminal that are connected by a coaxial cable. Rather than rely exclusively on two terminal passive components (e.g., resistor, inductor, capacitor), example coax MRI RF coils rely on the capacitance that can be created in the coax cable between the inner conductor and the outer conductor. The capacitance of the coil may be controlled by selectively disrupting (e.g., cutting, stripping) the outer conductor, the inner conductor, or the dielectric material disposed between the inner and outer conductor.

Abstract: An electrically-controlled failsafe switch is included in an MRI transmit-and-receive RF coil assembly so as to protect it from induced RF currents in the event it is disconnected from an MRI system, but inadvertently left linked to strong MRI RF fields during imaging procedures using other RF coils.

Abstract: An electrically-controlled failsafe switch is included in an MRI transmit-and-receive RF coil assembly so as to protect it from induced RF currents in the event it is disconnected from an MRI system, but inadvertently left linked to strong MRI RF fields during imaging procedures using other RF coils.

Abstract: In order to increase the signal to noise ratio, and thus increase the quality of images produced during pediatric MRI, a pediatric RF coil assembly includes a head coil and a flexible body coil in a single dedicated device shaped and sized for a child. The flexible body coil may be operable to at least partially surround and abut the body of the child located on the pediatric RF coil assembly, while the head coil may at least partially surround and abut the head of the child located on the pediatric RF coil assembly. In order to optimize workflow, the child may be positioned on the pediatric RF coil assembly in a first room and moved to a second room including an MRI system after the child is brought to sleep or sedated in the first room. The pediatric RF coil assembly and the child may be moved to the second room using a handle rotatably attached to the pediatric RF coil assembly, and may be positioned on a patient table of the MRI system when the imaging process is to begin.

Abstract: An electrically-controlled failsafe switch is included in an MRI transmit-and-receive RF coil assembly so as to protect it from induced RF currents in the event it is disconnected from an MRI system, but inadvertently left linked to strong MRI RF fields during imaging procedures using other RF coils.

Abstract: An electrically-controlled failsafe switch is included in an MRI transmit-and-receive RF coil assembly so as to protect it from induced RF currents in the event it is disconnected from an MRI system, but inadvertently left linked to strong MRI RF fields during imaging procedures using other RF coils.