An HF coil assembly for generating independent alternating magnetic fields in an examination volume of a magnetic resonance apparatus is presented, the HF coil assembly comprising a first coil pair of saddle coils and a second coil pair of saddle coils, each saddle coil having longitudinal conductor elements and curved conductor elements arranged along a common lateral surface of a circular cylinder having a cylinder axis. Each coil pair comprises curved conductor elements and longitudinal conductor elements which are interconnected at a high frequency. The saddle coils also have diagonal conductor elements and/or bridge elements that connect the longitudinal and curved conductor elements. The coil pairs are opposite to each other relative to the cylinder axis.

An MRI scanner and a method for operation of the MRI scanner are provided. The MRI scanner has a first receiving antenna for receiving a magnetic resonance signal from a patient in a patient tunnel, a second receiving antenna for receiving a signal having the Larmor frequency of the magnetic resonance signal, and a receiver. The second receiving antenna is located outside of the patient tunnel or near an opening thereof. The receiver has a signal connection to the first receiving antenna and the second receiving antenna and is configured to suppress an interference signal by the second receiving antenna in the magnetic resonance signal received by the first receiving antenna.

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 method of operating a magnetic resonance imaging (MRI) apparatus includes exciting a body coil of the MRI apparatus to emit a radio-frequency signal, determining a center frequency of a resonance curve of the body coil, and calculating a magnet target frequency based on the determined center frequency. A magnet is ramped to the magnet target frequency.

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.

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.

A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

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.

A double-resonant coil includes a closed conductor loop divided into at least two segments that are each connected via a second connection element configured to be converted from an electrically conductive state to an electrically insulating state. The double-resonant coil further includes an inductor or a capacitor connected in series to a first connection element so as to allow excitation of the closed conductor loop in a dipole mode at one frequency and with a homogeneous power distribution at a second frequency.