A magnetic resonance imaging (MRI) system can include a magnetic resonance imaging (MRI) radio frequency (RF) coil, which is or otherwise includes a degenerate birdcage coil (DBC) or a ladder coil. The MRI RF coil includes a row of meshes for operation in a half driving transmit mode. The meshes can include driving meshes and non-driving meshes, where each non-driving mesh is coupled between neighboring driving meshes. Driving meshes are electrically coupled to drivers, whereas non-driving meshes are not. The MRI RF coil may have enhanced transmit power efficiency and magnetic field uniformity with fewer drivers.
The present disclosure is directed to a balun package comprising a set of inductive baluns for a magnetic resonance imaging (MRI) radio frequency (RF) coil. A first resonant circuit and a second resonant circuit each comprise an inductor. A first decoupling circuit leg is between and shared by the first and second resonant circuits and includes one or more decoupling inductors and/or one or more decoupling capacitors. A first cable bundle is wound to form the inductor of the first resonant circuit or is otherwise spaced from and inductively coupled to the inductor of the first resonant circuit.
In some embodiments, the present disclosure relates to a multi-turn (MT) birdcage magnetic resonance imaging (MRI) radio-frequency (RF) coil. The MT birdcage MRI RF coil includes a first conductive ring, a second conductive ring, and a plurality of conductive rungs. Each of the plurality of conductive rungs includes a first end coupled to the first conductive ring, and a second end coupled to the second conductive ring. At least one of the first conductive ring and the second conductive ring includes more than one turn. The first conductive ring, the second conductive ring, and the plurality of conductive rungs form a plurality of meshes.
A magnetic resonance imaging (MRI) system can include a gapped degenerate birdcage magnetic resonance imaging (MRI) radio frequency (RF) coil. The gapped degenerate birdcage MRI RF coil is tuned to a degenerate mode and comprises a row of RF coil elements and a mechanical gap. The RF coil elements may also be referred to as channels or meshes. The row extends circumferentially around an axis of a cylindrical-like former, and mechanical gap separates a pair of directly neighboring RF coil elements in the row. A transformer, a partial overlap, or the like minimizes inductive coupling between the pair of directly neighboring RF coil elements.
In some embodiments, the present disclosure relates to a radio frequency (RF) surface coil for a magnetic resonance imaging (MRI) system. The RF surface coil includes a rigid lower member, at least one flexible upper member mechanically coupled to the rigid lower member, and one or more RF coil elements housed by the rigid lower member and the at least one flexible upper member. The at least one flexible upper member is dimensioned and manipulable to substantially conform the one or more RF coil elements to a portion of a patient anatomy to be imaged by the MRI system.
G01R 33/341 - Constructional details, e.g. resonators comprising surface coils
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
MRI apparatus for medical purposes; MRI diagnostic apparatus for medical purposes, namely, a magnetic resonance elastography system comprised primarily of a medical imaging vibrational transducer employing a gravitational design, a drive mechanism causing rotation of the transducer in phase with an MRI data acquisition sequence, and analysis and display embeded operating system software to track shear wave propagation, display elastogram maps, prescribe regions of interest, and calculate parameters indicative of tissue properties.
7.
PIN DIODE CURRENT REDUCTION FOR MRI TRANSMIT COILS
Various embodiments of the present disclosure are directed to a magnetic resonance imaging (MRI) radio frequency (RF) coil comprising a current-control circuit. A conductive trace forms a coil inductor and comprises a first trace segment and a second trace segment separated by the current-control circuit, which comprises a first reactive element and a circuit branch. The first reactive element is electrically coupled from the first trace segment to the second trace segment, and the circuit branch is electrically coupled in parallel with the first reactive element. The circuit branch comprises a second reactive element and a sub-circuit branch electrically coupled in parallel. The sub-circuit branch comprises a third reactive element and an electronic switch (e.g., a PIN diode) electrically coupled in series. The first reactive element and the third reactive element are one of capacitive and inductive, and the second reactive element is another one of capacitive and inductive.
The present disclosure relates to a magnetic resonance imaging (MRI) radio frequency (RF) array coil that includes first and second physical RF coils inductively coupled. A first matching circuit and a second matching circuit are coupled to the first physical RF coil and the second physical RF coil, respectively, and are coupled in a parallel configuration at a first RF port. A third matching circuit and a fourth matching circuit are coupled to the first physical RF coil and the second physical RF coil, respectively, and are coupled in an anti-parallel configuration at a second RF port. A first logical RF coil is formed by the first and second physical RF coils and the first and second matching circuits. A second logical RF coil, which is decoupled from the first logical RF coil, is formed by the first and second physical RF coils and the third and fourth matching circuits.
In some embodiments, the present disclosure relates to a flexible magnetic resonance imaging (MRI) radio frequency (RF) array coil configured to operate in at least one of a transmit (Tx) mode or a receive (Rx) mode. The MRI RF array coil includes a first row of saddle coil elements. At least a first saddle coil element and a second saddle coil element are in the first row. The first and second saddle coil elements partially overlap with one another. Each of the first and second saddle coil elements include a left loop and a right loop that is coupled to the left loop by two connection segments.
Various embodiments of the present disclosure are directed towards a magnetic resonance imaging (MRI) radio frequency (RF) coil configured to operate in at least one of a transmit mode or a receive mode. A first birdcage coil includes a pair of first-birdcage end rings and at least four first-birdcage rungs circumferentially arranged along the first-birdcage end rings. A second birdcage coil including a pair of second-birdcage end rings and at least four second-birdcage rungs circumferentially arranged along the second-birdcage end rings. The first and second birdcage coils neighbor and are spaced by a first non-zero distance along an axis. The axis is surrounded by the first-birdcage end rings and the second-birdcage end rings, and the first non-zero distance is greater than individual lengths of the first and second birdcage coils along the axis.
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.
Various embodiments of the present disclosure are directed towards a magnetic resonance imaging (MRI) radio frequency (RF) coil. The MRI RF coil comprises a first conductive ring and a second conductive ring. A plurality of rung groups extend between the first and second conductive rings. The plurality of rung groups are spaced uniformly about the first conductive ring. Each of the plurality of rung groups comprises a plurality of conductive rungs extending between and connected to the first and second conductive rings. The plurality of conductive rungs of each of the plurality of rung groups are azimuthally separated from one another by a first azimuth angle. Each of the plurality of rung groups is separated from a neighboring rung group by a spacing that forms a window. Each of the windows have a second azimuth angle that is greater than the first azimuth angle.
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.
Various embodiments of the present disclosure are directed towards a magnetic resonance imaging (MRI) knee coil comprising a local shim coil. The local shim coil is disposed in a housing of the MRI knee coil. An electromagnetic coil is also disposed in the housing and spaced from the local shim coil. The local shim coil comprises one or more conductors. Each of the conductors of the local shim coil are disposed on a semi-cylindrical surface, and the semi-cylindrical surface extends laterally from a first side of the housing to a second side of the housing. The local shim coil is configured to generate a local shimming magnetic field that reduces a localized magnetic field inhomogeneity caused by a susceptibility artifact disposed in a knee of a patient.
G01R 33/3875 - Compensation of inhomogeneities using correction coil assemblies, e.g. active shimming
A61B 5/00 - Measuring for diagnostic purposes Identification of persons
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
G01R 33/34 - Constructional details, e.g. resonators
G01R 33/54 - Signal processing systems, e.g. using pulse sequences
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).
A system for positioning of an RF surface coil to several imaging tables has a table coupling device with first and second sides and table engagement features. The first side has a planar surface to mate with a first imaging table. The second side has a contoured surface having a curvature to mate with a second imaging table. A coil coupling device selectively couples to each of the first and second sides of the table coupling device in respective first and second configurations. The coil coupling device selectively rotates about a rotation axis perpendicular to the first side, and selectively translates along a translation axis perpendicular to the rotation axis. The coil coupling device has one or more coil engagement features to selectively engage the RF surface coil in each of a horizontal position and vertical position of the RF surface coil with respect to the table coupling device.
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.
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.
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.
Embodiments relate to MRI coils and arrays comprising an all-in-one circuit that can perform all the functions of decoupling, balun, tuning, and preamplifier decoupling. One example embodiment is a magnetic resonance imaging (MRI) radio frequency (RF) coil element, comprising: a coil comprising at least one inductor, at least one capacitor, and two connection points; a lattice balun comprising two inputs and two outputs, wherein the two inputs of the lattice balun are connected across the two connection points of the coil; one or more shunt reactive elements connected across the two outputs of the lattice balun, wherein the one or more shunt reactive elements comprises at least one of one or more shunt capacitors or one or more shunt inductors; one or more protection diodes in parallel with the one or more shunt reactive elements; and a low input impedance preamplifier in parallel with the one or more protection diodes.
1 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.
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.
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.
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
G01R 33/34 - Constructional details, e.g. resonators
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.
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.
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.
G01R 33/36 - Electrical details, e.g. matching or coupling of the coil to the receiver
G01R 33/34 - Constructional details, e.g. resonators
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
27.
Hidden coil transmission lines in magnetic resonance imaging (MRI) coil
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.
G01R 33/36 - Electrical details, e.g. matching or coupling of the coil to the receiver
G01R 33/341 - Constructional details, e.g. resonators comprising surface coils
G01R 33/34 - Constructional details, e.g. resonators
G01R 33/3415 - Constructional details, e.g. resonators comprising surface coils comprising arrays of sub-coils
28.
Decoupling magnetic resonance imaging (MRI) radio frequency (RF) coil elements with high acceleration factor in parallel transmit (pTx) or receive (Rx) coils using fewer channels
0 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.
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.
A single-layer magnetic resonance imaging (MRI) radio frequency (RF) coil element configured to operate in a transmit (Tx) mode and a receive (Rx) mode, the coil element comprising: an LC coil and a failsafe circuit electrically connected with the LC coil, where the LC coil, upon resonating with a primary coil of an MRI system, generates a local amplified Tx field based on an induced current generated in the LC coil by inductive coupling between the LC coil and the primary coil, where the failsafe circuit provides, upon injection of a forward DC bias current into the failsafe circuit, a first impedance, and upon the absence of the forward DC bias current, a second, higher impedance; where the failsafe circuit, upon the single-layer MRI RF coil array element being disconnected from an MRI system, provides the second, higher impedance, and reduces the magnitude of the induced current.
0 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.
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.
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
A61M 25/01 - Introducing, guiding, advancing, emplacing or holding catheters
A magnetic resonance imaging (MRI) radio frequency (RF) coil array configured to operate in a transmit (Tx) mode or in a receive (Rx) mode, comprising: a plurality of rows configured in an anatomy-specific shape, a row including a plurality of RF coil elements, an RF coil element including an LC coil and a magnitude/phase control component, where the LC coil, upon resonating with a primary coil at the working frequency of the primary coil, generates a local amplified Tx field based on an induced current in the LC coil, where a magnitude or a phase of the induced current is independently adjustable, where the magnitude/phase control component is configured to adjust the magnitude or phase of the induced current, and where the magnitude or phase of the induced current of a first RF coil element is independently adjustable from that of a second, different RF coil element.
A magnetic resonance imaging (MRI) radio frequency (RF) coil array configured to operate in a transmit (Tx) mode or 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 a 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.
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.
G01R 33/36 - Electrical details, e.g. matching or coupling of the coil to the receiver
A61B 5/00 - Measuring for diagnostic purposes Identification of persons
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
G01R 33/28 - Details of apparatus provided for in groups
36.
Radio frequency (RF) transmit system for digital RF current source
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.
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.
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.
09 - Scientific and electric apparatus and instruments
10 - Medical apparatus and instruments
Goods & Services
Radio frequency coils for MRI diagnostic apparatus; parts and fittings for the aforesaid goods. MRI diagnostic apparatus; parts and fittings for the aforesaid goods.
43.
Current magnitude control at different sections in one coil
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 (λ/4) of the RF signal, or an odd integer multiple of λ/4 of the RF signal.
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.
A61B 5/00 - Measuring for diagnostic purposes Identification of persons
G01R 33/34 - Constructional details, e.g. resonators
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
Example minimalist magnetic resonance imaging (MRI) radio frequency (RF) coils that are connected to off coil circuitry by capacitive coupling plates are described. A minimalist MRI RF coil may have some elements that form a traditional coil located off the coil in off coil circuitry. An MR procedure may involve a number of minimalist MRI RF coils that are moved through an excitation zone as a patient is moved through the excitation zone. Example minimalist MRI RF coils may be selectively connected to off coil circuitry while the coils are in the excitation zone. The coupling may be made by capacitive coupling plates. Unlike conventional systems, example systems have capacitive coupling plates with properties that facilitate maintaining a constant capacitance between a coupling plate associated with the coil and coupling plates associated with the off coil circuitry as the coupling plates move relative to each other.
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.
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.
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.
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.
A61B 5/00 - Measuring for diagnostic purposes Identification of persons
G01R 33/34 - Constructional details, e.g. resonators
A61B 10/02 - Instruments for taking cell samples or for biopsy
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
A61B 90/17 - Fixators for body parts, e.g. skull clampsConstructional details of fixators, e.g. pins for soft tissue, e.g. breast-holding devices
A61B 90/11 - Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups , e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis with guides for needles or instruments, e.g. arcuate slides or ball joints
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 biopsy plate, 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. The biopsy plate is removable without removing either of the MRI coils.
A61B 5/05 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
A61B 10/02 - Instruments for taking cell samples or for biopsy
A61B 5/00 - Measuring for diagnostic purposes Identification of persons
A61B 19/00 - Instruments, implements or accessories for surgery or diagnosis not covered by any of the groups A61B 1/00-A61B 18/00, e.g. for stereotaxis, sterile operation, luxation treatment, wound edge protectors(protective face masks A41D 13/11; surgeons' or patients' gowns or dresses A41D 13/12; devices for carrying-off, for treatment of, or for carrying-over, body liquids A61M 1/00)
54.
Failsafe protection from induced RF current for MRI RF coil assembly having transmit functionality
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.
31P MRS of the kidney. The apparatus also includes logic configured to receive spectrum data from the kidney. The spectrum data is produced in response to applying the NMR energy to the kidney. The apparatus also includes logic configured to provide objective, quantitative kidney viability data (e.g., PME/Pi, ATP/ADP) from the spectrum data. More generally, MRI/MRS compatible HPP apparatuses are configured to interact with dedicated NMR spectroscopy apparatuses.
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.
