Abstract: Various embodiments of the present disclosure are directed towards a magnetic resonance imaging (MRI) radio frequency (RF) coil array configured to operate in at least one of a transmit mode or a receive mode on a cylindrical former. The MRI RF coil array includes at first row of RF coil elements. Each row of RF coil elements includes at least three RF coil elements that circumferentially surround a cylindrical axis. The MRI RF coil array also includes a first birdcage coil that circumferentially surrounds the first row of RF coil elements. Each RF coil element of the first row is configured to inductively couple to the first birdcage coil and to each other RF coil elements. The first birdcage coil has an impedance configured to negate inductive coupling between the RF coil elements of the first row.

Abstract: Embodiments relate to MRI coils and arrays comprising transmission lines to enforce periodic conditions. An example embodiment comprises a MRI RF coil array comprising: a plurality of assemblies, wherein each assembly of the plurality of assemblies comprises: a two-port device of that assembly, wherein the two-port device of that assembly is similar to the two-port device of each other assembly of the plurality of assemblies, and wherein the two-port device of that assembly comprises at least one associated inductor configured to, in a Tx mode, generate at least a portion of a B1 field; and a transmission line of that assembly, wherein a length of the transmission line of that assembly can be similar to a length of the transmission line of each other assembly of the plurality of assemblies, wherein the plurality of assemblies are connected together in a loop.

Abstract: Various embodiments of the present disclosure are directed towards a radio frequency (RF) coil comprising a first combination coil and a second combination coil. The first combination coil comprises a first resonant coil and a first resonant shield coupled inductively or by a capacitor, and the first combination coil has a first resonant frequency and a second resonant frequency. The second combination coil comprises a second resonant coil and a second resonant shield coupled inductively or by a capacitor, and the second combination coil has a third resonant frequency and a fourth resonant frequency. The first and second resonant coils are inductively coupled to each other and respectively to the second and first resonant shields. The first and third resonant working frequencies are the same, and the second and fourth resonant isolation frequencies are such that inductive coupling between the first and second resonant coils is negated.

Abstract: Various embodiments of the present disclosure are directed towards a magnetic resonance imaging (MRI) head coil comprising an open shield. A transmit coil surrounds a phased array receive coil and comprises a resonant birdcage structure. The resonant birdcage structure comprises multiple transmit rungs spaced in a first closed path, and inter-rung spacing at one or more first locations on the first closed path is greater than at a remainder of the first closed path. The open shield surrounds the transmit coil and comprises a non-resonant birdcage structure. The non-resonant birdcage structure comprises multiple shield rungs spaced in a second closed path. The shield rungs are elongated in parallel with the transmit rungs, and inter-rung spacing at one or more second locations on the second closed path is greater than at a remainder of the second closed path. Further, the second location(s) respectively and radially border the first location(s).

Abstract: A method for controlling an interventional magnetic resonance imaging (iMRI) system configured to control a heating mode of an iMRI guidewire, the method comprising: controlling, during an iMRI procedure, a magnitude of an induced current in a single-layer MRI radio frequency (RF) coil used in the iMRI procedure, or a phase of the induced current by adjusting at least one of: a difference between a working frequency of a whole body coil (WBC) used in the iMRI procedure and a resonant frequency of the single layer MRI RF coil, a coil loss resistance of the single layer MRI RF coil, or a blocking impedance of an LC circuit connected in parallel with the single-layer MRI RF coil; and controlling a heating mode of the guidewire based, at least in part on the magnitude or phase.

Abstract: Embodiments relate to multi-turn magnetic resonance imaging (MRI) radio frequency (RF) coil arrays employing ring decoupling, and MRI apparatuses employing such coil arrays. One example embodiment comprises: four or more RF coil elements that enclose a cylindrical axis, wherein each RF coil element comprises a first capacitor of that RF coil element and a loop comprising at least two turns; and a ring structure that facilitates decoupling of the RF coil elements, wherein each RF coil element is adjacent to two neighboring RF coil elements and is non-adjacent to one or more other coil elements, wherein each RF coil element has a shared side in common with the ring structure, wherein the shared side comprises a second capacitor of that RF coil element with a capacitance selected to mitigate inductive coupling between that RF coil element and non-adjacent RF coil elements.

Abstract: Embodiments relate to birdcage coils with in-plane open RF shielding capable of operating at 7T and higher field strength. One example embodiment comprises a first birdcage circuit and second birdcage circuit, each comprising two rings, N rungs that electrically connect the two rings of that circuit, a plurality of capacitors in the first birdcage circuit to form a first birdcage coil, and an optional plurality of capacitors in the second birdcage circuit to form a second birdcage coil when included or a non-resonant RF shield when omitted, wherein the first birdcage circuit is electrically isolated from the second birdcage circuit, wherein the first birdcage circuit and the second birdcage circuit have a common cylindrical axis, and wherein the N rungs of the second birdcage circuit are azimuthally rotated through a first angle relative to the N rungs of the first birdcage circuit.

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: Embodiments relate to cylindrical MRI coils with at least one row as a birdcage row in a transmit mode. One example embodiment is a MRI Radio Frequency (RF) coil array comprising two or more rows of four or more RF coil elements each. Each of the RF coil elements can be configured to resonate at a working frequency of the coil array in a receive mode. At least one of the rows can be configured as a birdcage coil in the transmit mode, and the two or more rows can inductively couple together such that all the two or more rows can resonate together in the transmit mode at the working frequency.

Abstract: Embodiments relate to cylindrical MRI coil arrays with reduced coupling between coil elements. One example embodiment comprises two or more rows, wherein each row comprises at least three RF coil elements of that row enclosing a cylindrical axis; and a ring comprising an associated portion of each RF coil element of a first row and a second row electrically connected together, wherein the associated portion of each RF coil element of the first row and of each RF coil element of the second row comprises an associated capacitor of that RF coil element, and wherein the associated capacitor of that RF coil element is configured to reduce coupling among the RF coil elements of the first row and the RF coil elements of the second row.

Abstract: Embodiments relate to MRI coils with a reduced number of baluns. One example embodiment is a MRI coil comprising: a plurality of coil elements in one or more groups of coil elements, wherein each group of coil elements comprises at least two coil elements and a shared trace comprising portions of associated traces of each coil element of that group RF shorted together, and wherein, for each coil element of that group, the shared trace of the group is RF shorted to a shield of an associated coaxial cable for that coil element; and one or more baluns, wherein, for each group of coil elements, at least one balun of the one or more baluns is configured to mitigate leakage current on the coaxial cable of each coil element of that group of coil elements.

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: Embodiments relate to MRI coils and arrays comprising transmission lines to enforce periodic conditions. An example embodiment comprises a MRI RF coil array comprising: a plurality of assemblies, wherein each assembly of the plurality of assemblies comprises: a two-port device of that assembly, wherein the two-port device of that assembly is similar to the two-port device of each other assembly of the plurality of assemblies, and wherein the two-port device of that assembly comprises at least one associated inductor configured to, in a Tx mode, generate at least a portion of a B1 field; and a transmission line of that assembly, wherein a length of the transmission line of that assembly can be similar to a length of the transmission line of each other assembly of the plurality of assemblies, wherein the plurality of assemblies are connected together in a loop.

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: Embodiments relate to MRI RF multi-tune coil elements, arrays, and MRI systems comprising such elements. One example embodiment comprises: a LC coil comprising one or more matching points; and two or more matching branches, each of which connected to the LC coil at matching point of the one or more matching points that is associated with that matching branch, wherein each matching branch comprises an associated set of one or more RF traps configured to block each frequency of two or more frequencies other than a frequency associated with that matching branch, and wherein each matching branch is configured to match to an associated predetermined impedance at the frequency associated with that matching branch.

Abstract: Embodiments relate to integrated MRI (Magnetic Resonance Imaging) coil arrays that can be stored within a patient table when not in use. One example embodiment comprises a coil array comprising: at least one flat spine-like coil array arranged within a patient table of a MRI system; and flexible coil array(s) configured to be in a stored position within the patient table, wherein, in the stored position, the flexible coil array(s) are one of within or under the at least one flat spine-like rigid coil array, wherein the flexible coil array(s) are further configured to be in an extended position, wherein, in the extended position, the flexible coil array(s) is configured to be extracted from the patient table and to wrap around at least one anatomical region of a patient on the patient table to facilitate MRI of the at least one anatomical region.

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.