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.

A permittivity apparatus that includes a permittivity material is received. The permittivity material includes one or more types of high permittivity materials. The permittivity apparatus is configured to be placed near or into a region of interest to be imaged. The permittivity apparatus is placed near or into the region of interest such that placing the permittivity apparatus near or into the region of interest changes a local stored electromagnetic energy distribution around or inside the region of interest. MRI images including the region of interest are then acquired. An MRI system includes radiofrequency coils and a permittivity apparatus that includes one or more types of high permittivity materials. The permittivity apparatus is configured to be placed near or into a region of interest to be imaged.

Systems and methods for MR signal synchronization may be provided. The method may include determining a time difference in a local clock generator at a coil side assembly compared to a system clock generator at a system side assembly. The method may include maintaining a constant phase difference between clock signals generated by the local clock generator and by the system clock generator by correcting the local clock generator based on the time difference. The method may include acquiring MR echo signals by scanning at least a part of a subject in response to the clock signal generated by the corrected local clock generator. The method may further include digitizing the MR echo signal at the coil side assembly.

The embodiments relate to a magnetic resonance imaging device, where the cladding of the patient bore of the MR imaging device includes a conductive layer.

A method to calibrate a nuclear magnetic resonance tool is disclosed having steps of starting a nuclear magnetic resonance sequence from the nuclear magnetic resonance tool, disabling an active damping circuit in the nuclear magnetic resonance tool, collecting auxiliary calibration data for the nuclear magnetic resonance tool, estimating a natural Q value for the nuclear magnetic resonance tool, determining an optimal active damping setting for the tool, deploying the optimal active damping setting for the tool, collecting nuclear magnetic resonance response data generated from the nuclear magnetic resonance sequence and calibrating the nuclear magnetic resonance data.

A magnetic resonance measurement apparatus according to the present invention includes a first LC circuit that forms an oscillating magnetic field that causes an object to exhibit magnetic resonance. The first LC circuit includes a parallel connection assembly including a diode. The parallel connection assembly further includes a diode connected, in parallel and in reverse direction, to the diode, or an inductor connected in parallel to the diode. In a first state in which oscillating voltage for forming the oscillating magnetic field is applied to the first LC circuit, the diode of the parallel connection assembly functions as a short-circuit such that the resonance frequency of the first LC circuit becomes a first resonance frequency. In a second state in which oscillating voltage is not applied to the first LC circuit, the diode of the parallel connection assembly functions as capacitance such that the resonance frequency of the first LC circuit becomes a second resonance frequency that is different from the first resonance frequency.

A method to perform continuous-wave NMR measurements of nuclear magnetization at high magnetic fields, above 2.5 T, without analog down-mixing is described. An FPGA controls a digital clock pulse which is used to stimulate a resonant circuit and provide a reference signal. An algorithm determines the real portion of a resonant circuit signal near the Larmor frequency of the species of interest using only two measurements of the waveform per cycle. The FPGA automatically alters a variable capacitance to tune the resonant circuit to the Larmor frequency.

A method to perform continuous-wave NMR measurements of nuclear magnetization at high magnetic fields, above 2.5 T, without analog down-mixing is described. An FPGA controls a digital clock pulse which is used to stimulate a resonant circuit and provide a reference signal. An algorithm determines the real portion of a resonant circuit signal near the Larmor frequency of the species of interest using only two measurements of the waveform per cycle. The FPGA automatically alters a variable capacitance to tune the resonant circuit to the Larmor frequency.

An NMR measurement apparatus includes a transmitting antenna including a transmitter coil, a capacitor, a dissipating component and a restricting component, and a receiving antenna physically separated from the transmitting antenna. A processor is configured to apply a drive signal at a first voltage level to generate a transmission signal having a selected transmission frequency, where the receiving antenna is deactivated during generation, connect the dissipating component to the transmitter coil to dissipate stored energy in the transmitter coil, connect the restricting component to the transmitter coil to restrict the transmitting antenna to a second voltage level smaller than the first voltage level and based on a voltage of NMR signals from the sensitive volume, activate the receiving antenna and detect a NMR signal, where the restricting component is connected to the transmitter coil and restricts the transmitting antenna during the activating and the detecting.

A method of magnetic resonance tomography includes arranging an object in a static magnetic field, subjecting it to radiofrequency (RF) pulses and magnetic field gradients for creating spatial encoding of magnetic resonance signals, acquiring the signals with at least two RF receive coils, each with a self-resonance frequency and a spatially restricted sensitivity profile, and reconstructing an object image. Spatial encoding of the signals by the gradients and the profiles is utilized, wherein the profile of at least one of the coils is subjected to a temporal sensitivity profile modulation while acquiring the signal. The self-resonance frequency of the at least one coil is set within a predetermined receive bandwidth of a constant resonance frequency value during the modulation. The reconstructing further utilizes the modulation for obtaining additional spatial information to the spatial encoding of the signals by the gradients. Furthermore, an MRI device is described.