Embodiments of a compact portable nuclear magnetic resonance (NMR) device are described which generally include a housing that provides a magnetic shield; an axisymmetric permanent magnet assembly in the housing and having a bore, a plurality of magnetic elements that together provide a well confined axisymmetric magnetization for generating a near-homogenous magnetic dipole field B.sub.0 directed along a longitudinal axis and providing a sample cavity for receiving a sample, and high magnetic permeability soft steel poles to improve field uniformity: a shimming assembly with coils disposed at the longitudinal axis for spatially correcting the near homogenous magnetic field B.sub.0; and a spectrometer having a control unit for measuring a metabolite in the sample by applying magnetic stimulus pulses to the sample, measuring free induction delay signals generated by an ensemble of hydrogen protons within the sample; and suppressing a water signal by using a dephasing gradient with frequency selective suppression.

A method includes disposing a downhole tool having a magnet assembly into a wellbore. The method includes generating, using the magnet assembly, a magnetic polarization in a volume into a subterranean region about the wellbore. The method also includes emitting an excitation in the magnetic polarization in the volume in the subterranean region. The method includes detecting, by at least one antenna, a nuclear magnetic resonance response to the excitation of the volume in the subterranean region. The method also includes determining a property of the subterranean region based on the nuclear magnetic resonance response.

The present disclosure is directed to a coil unit decoupling apparatus and a magnetic resonance system. The apparatus is connected to a first coil unit and a second coil unit in a magnetic resonance system, and is configured to separate, by using a distribution characteristic of a spatial quadrature field between the first coil unit and the second coil unit, a Helmholtz signal and an anti-Helmholtz signal from signals received from the first coil unit and the second coil unit, so as to implement decoupling between the first coil unit and the second coil unit. This facilitates the complexity of decoupling coil units being reduced.

Techniques are disclosed for a local coil and a magnetic resonance imaging system. The local coil includes a plurality of coil units that respectively receive magnetic resonance signals generated when magnetic resonance detection is performed on a detected object, and a signal processing unit configured to perform processing including signal preprocessing and quadrature modulation on the magnetic resonance signals received by the plurality of coil units to obtain signals to be transmitted. Contactless connectors are also disclosed, each being configured to couple the signals to be transmitted to a contactless connector at the MR system side.

A magnetic resonance detection (MRD) system for and methods of detecting and classifying multiple chemical substances is disclosed. In one example, the presently disclosed MRD system is a nuclear quadrupole resonance (NQR) detection system that provides multi-frequency operation for substantially full coverage of the explosive NQR spectrum using a broadband transmit/receive (T/R) switch (or duplexer) and a single multi-frequency radio frequency (RF) transducer. More particularly, the MRD system provides a frequency-agile system that can operate over a wide band of frequencies or wavelengths. Further, a method of detecting and classifying various chemical substances is provided that includes pulse sequencing with “frequency hopping,” phase cycling for reducing or substantially eliminating background noise, and/or a process of mitigating amplitude modulation (AM) radio interference.

Signal generation devices including an auto-tuning electronic circuit module for generating tuned output signals are disclosed. The auto-tuning electronic circuit module may include a tunable resonant electronic circuit element for providing a tuned output signal, including a voltage divider element and a tuning array element and control element.

The disclosure relates to a hybrid orthogonal signal generator, a coil transmission front-end device, an RF coil system, and an MRI system. The hybrid orthogonal signal generator has an input end for receiving an RF signal, generates a hybrid orthogonal excitation signal on the basis of the RF signal, and provides the hybrid orthogonal excitation signal by means of an output end of the hybrid orthogonal signal generator, and comprises: a first conductor, arranged in a plane and being arc-shaped; and a second conductor having mutual inductance with the first conductor, the second conductor being connected between the input end and output end, wherein the first conductor and second conductor are parallel and arranged as mirror images of each other. The hybrid orthogonal signal generator has a compact size and is suitable for providing hybrid orthogonal excitation signals for an MRI system with a low field strength.

A magnetic resonance radio frequency transmission device (140) for generating and applying a radio frequency excitation field B.sub.1 for the purpose of magnetic resonance examination comprises a birdcage coil (144) and a plurality of M radio frequency amplifier units for providing radio frequency power at a magnetic resonance frequency to the birdcage coil (144) via a plurality of M activation ports (158) selected out of the plurality of N activation ports (158). In an operational state of the birdcage coil (144) each radio frequency amplifier unit (142) is electrically connected and is arranged in close proximity to an activation port (158). Among the plurality of M radio frequency amplifier units (142), there is established a fixed relationship of adjustable phase angles (φ) of the magnetic resonance radio frequency power provided by the plurality of M radio frequency amplifier units (142); a method of generating and applying a radio frequency excitation field B for the purpose of magnetic resonance examination, using such magnetic resonance radio frequency transmission device (140); and a magnetic resonance imaging system (110) configured for acquiring magnetic resonance images of at least a portion of a subject of interest (120), comprising such magnetic resonance radio frequency transmission device (140).

Phase variations of the transverse magnetization in magnetic resonance induced by superimposed physical phenomenae or by intrinsic deviations of the main magnetic B0 field are separated from Feature Space set by demodulation and deconvolution, either by electrical circuits or by equivalent computational methods, permitting mapping and measurement of these induced phase variations independent of Feature Space.

In a method and magnetic resonance (MR) apparatus to acquire MR data of a target region that includes a metal object, an MR sequence that includes at least one radio-frequency excitation to be emitted via a radio-frequency coil arrangement is used. A radio-frequency coil arrangement having multiple coil elements that can be controlled independently with different amplitude and/or phase is used. The amplitudes and/or phases of the coil elements that describe the polarization of the radio-frequency field are selected to at least partially reduce artifacts arising in the metal object due to the radio-frequency excitation, in comparison to a homogeneous, circular polarization of the radio-frequency field of the radio-frequency field in the target region.