A birdcage coil for a magnetic resonance imaging (MRI) system, the birdcage coil includes: a relatively planar birdcage coil section, including a pair of relatively planar ring portions and a plurality of conductive, elongated rungs extending between the pair of relatively planar ring portions; and a relatively domed birdcage coil section, including a pair of relatively domed ring portions and a plurality of conductive, elongated rungs extending between the pair of relatively domed ring portions. The relatively domed birdcage coil section is releasably coupled to the relatively planar birdcage coil section. In an embodiment, at least two sets of the relatively planar and domed birdcage coil sections are provided, where each of the at least two sets is configured to a different MRI application.

The present disclosure relates to a control system and methods implemented on the control system. The control system includes a tuning/detuning system and a diagnosis system. The tuning/detuning system includes a first voltage source, a second voltage source, one or more coil arrays, and one or more tuning/detuning circuit drivers corresponding to the one or more coils arrays, respectively. The diagnosis system includes a first current sampling circuit and a processor. The first current sampling circuit is configured to obtain a first current. The processor is configured to diagnose the tuning/detuning system based on the first current.

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.

A coil assembly includes: a radio frequency (RF) coil operable to be placed over a portion of a subject; a quarter-wave transformer coupled to the RF coil and configured to transform a characteristic impedance of the RF coil; and a diode placed behind the quarter-wave transformer and away from the RF coil, wherein the diode is operable to: (i) when the diode is forward biased, the diode turns the quarter-wave transformer into an open circuit such that the power amplifier drives the RF coil with sufficient electrical power for the RF coil to transmit an RF pulse into the portion of the subject; and (ii) when the diode is provided zero or revers bias, the diode turns the quarter-wave transformer into a short circuit such that the RF coil is detuned from a Lamor frequency of nuclei of interest immersed in the main magnet.

The present disclosure relates to a control system and methods implemented on the control system. The control system includes a tuning/detuning system and a diagnosis system. The tuning/detuning system includes a first voltage source, a second voltage source, one or more coil arrays, and one or more tuning/detuning circuit drivers corresponding to the one or more coils arrays, respectively. The diagnosis system includes a first current sampling circuit and a processor. The first current sampling circuit is configured to obtain a first current. The processor is configured to diagnose the tuning/detuning system based on the first current.

Provided are coil assemblies, and holding assemblies, devices and systems comprising the coil assembly as well as methods of use thereof. The coil assembly includes a first radio frequency coil element configured for transmitting a first radio frequency signal through a region of interest of a subject or test sample, the first radio frequency signal for exciting a first spin species in the region of interest. The coil assembly also includes a second radio frequency coil element configured for resonating at a second radio frequency signal to receive a magnetic resonance signal from a second spin species from the region of interest. The first radio frequency signal and the second radio frequency signal are separated by a frequency interval. A drive circuitry is connected to the second radio frequency coil element. A first decoupling circuit prevents coil coupling between the first radio frequency coil element and/or a transmitter coil element. A second decoupling circuit prevents coil coupling between the second radio frequency coil element and the transmitter coil element.

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.

An apparatus for performing a downhole nuclear magnetic resonance (NMR) experiment on a subsurface material in a volume of interest includes: a carrier configured to be conveyed through a borehole penetrating the subsurface material; an NMR sensor assembly disposed on the carrier and comprising a static magnetic field source configured to polarize nuclei of the subsurface material in the volume of interest and an antenna configured to receive NMR signals; and a receiver circuit disposed on the NMR sensor assembly and configured to process received NMR signals to perform the downhole NMR experiment; wherein (i) the receiver circuit is disposed in a pressure-excluding enclosure and (ii) the antenna, the static magnetic field source, and the pressure-excluding enclosure are disposed in a pressure-balancing fluid that is at least partially enclosed by an enclosure of non-metallic material.

An RF antenna element with a detuning system in which the RF antenna element comprises a resonant electrically conductive loop. The (de)tuning system comprising a switching element to (de)tune the resonant electrically conductive loop. The (de)tuning system element includes an electroluminescent element coupled to the resonant electrically conductive loop. The (de)tuning system includes a photo-electrical conversion element to detect an electro-luminescent signal from the electroluminescent element.

Some implementations provide an MRI system that includes: a housing having a bore accommodating a portion of a subject; a main magnet enclosed by said housing and configured to generate a substantially uniform magnet field within the bore; a gradient sub-system to provide perturbations to the substantially uniform magnet field; a flexible coil assembly configured to (i) receive radio frequency (RF) signals from the subject in response to the portion of the subject being scanned, and (ii) generate and apply B.sub.0 shimming to improve a field homogeneity of the substantially uniform magnetic field; and a control unit configured to: drive the gradient sub-system using a gradient waveform; and receive measurement results responsive to the gradient waveform such that a coupling between the gradient sub-system and the flexible coil assembly is determined and subsequently reduced in response to the determined coupling exceeding a pre-determined threshold.