A technique for reconciling large sensitivity area and high sensitivity for deep part in a multi-channel array coil of an MRI apparatus without complicating the configuration, and realizing both higher speed imaging and high image quality is provided. An RF coil (array coil) of a magnetic resonance imaging apparatus comprising a plurality of subcoils is provided. At least one of the subcoils is a first subcoil of which resonance frequency as that of the subcoil alone differs from magnetic resonance frequency. The first subcoil is adjusted so that it magnetically couples with a second subcoil, which is at least one other subcoil, and thus resonates at the same frequency as the magnetic resonance frequency. Input and output terminals of the first subcoil and the second subcoil are connected to different low input and output impedance signal processing circuits, respectively.

A pyrolysis system for evaluating a source rock sample from a subterranean reservoir and methods are described. The pyrolysis system includes a reactor vessel including a body with an open end, a cover attachable to the body, a heating system, a collector assembly. The body and the cover define a sealable chamber; a source rock sample holder sized to be received inside the sealable chamber; and a sensor system. The sensor system includes a direct sensor assembly associated with the source rock sample holder, sized to be received inside the sealable chamber, and operable to measure properties of the source rock sample in the source rock sample holder; and a pyrolysis products sensor assembly in fluid communication with the collector assembly of the reactor vessel.

A coil unit decoupling device and a magnetic resonance system. The device comprises a first phase shift circuit, a second phase shift circuit and a first crossover element, and the first crossover element is a capacitor or inductor, wherein a first connecting end of the first phase shift circuit is connected with a first port of a first coil unit, a second connecting end of the first phase shift circuit is connected with a first connecting end of the first crossover element, a first connecting end of the second phase shift circuit is connected with a first port of a second coil unit, a second connecting end of the second phase shift circuit is connected with a second connecting end of the first crossover element, and the first coil unit and the second coil unit are located in a magnetic resonance system.

A method for designing gradient coils includes the following steps: a) defining an imaging volume as an ellipsoid; b) defining an elliptic-cylindrical surface enclosing the said ellipsoid; c) defining the current density at each point of the surface by a series of basis functions and corresponding coefficients expressed in elliptic cylindrical coordinates; d) describing the magnetic field generated at a generic point by the above defined current density integrated all over the said entire elliptic-cylindrical surface; e) determining the values of the coefficients of the basis functions by solving the inverse function for describing the magnetic field; f) generating a discrete winding patter of a gradient coil by using a stream function method from the continuous current density and by using a series of scattered contours of the stream function as the design of the winding patters according to a set total number of windings.

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.

A high-frequency array coil for an MRI apparatus includes: a plurality of coil units each of which includes a plurality of RF reception coils including a conductor loop and adjusted to receive a magnetic resonance signal; an extension conductor which includes a part of each conductor loop of each RF reception coil of the plurality of coil units and a conductor connecting the parts; and an extension conductor control circuit which adjusts a reception frequency of the extension conductor. The extension conductor is disposed so as to be wound in a spiral shape when the extension conductor is disposed on a subject and a direction of a magnetic field to be detected intersects a direction of a magnetic field detected by the RF reception coil constituting the coil unit. Accordingly, the detection efficiency of an RF coil can be increased and an image with a high SNR can be obtained.

An apparatus, method, and system are disclosed for improving uniformity of RF magnetic field in an MRI system, and thereby improving both signal-to-noise ratio and uniformity of imaging sensitivity across a sampling volume, to provide more uniform MRI images. A passive LC resonator develops induced EMF and induced currents in a primary RF magnetic field; the secondary magnetic field produced thereby can counteract magnetic field amplitude gradients to produce a more homogeneous RF magnetic field. In systems with separate transmit and receive coils, a shunt detuning circuit is pulsed ON to prevent interference during the transmit period. In a dual-frequency MRI machine (e.g. 19F and 1H), the RF magnetic field at the lower operating frequency can be homogenized by tuning the resonance of the passive resonator between the two operating frequencies. Another resonator can improve RF field uniformity at the higher operating frequency. Variants and experimental results are disclosed.

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.

A reconfigurable metamaterial is used to enhance the reception field of a radio frequency (“RF”) coil for use in magnetic resonance imaging (“MRI”). In general, the metamaterial can be a metasurface, which may be flexible, having a periodic array of resonators. Each resonator in the periodic array can be defined as a unit cell of the metamaterial and/or metasurface. The unit cells include a first conductor and a second conductor separated by an insulator layer. The first conductor can be a solid conductor and the second conductor can be a conductive fluid (e.g., a liquid metal, a liquid metal alloy) contained within a microfluidic channel. Varying the volume of conductive fluid in each unit cell adjust the signal enhancement ratio of the metamaterial.

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.