The exemplary system and method facilitate excitation of RF magnetic fields in ultra-high field (UHF) magnetic resonance (MRI) systems (e.g., MRI/NMR system) using a slotted waveguide array (SWGA) as an exciter coil. The exemplary exciter coil, in some embodiments, is configurable to provide RF magnetic field B.sub.1.sup.+ with high field-uniformity, with high efficiency, with excellent circular polarization, with negligible axial z-component, with arbitrary large field of view, and with exceptional possibilities for field-optimizations via RF shimming.

In some embodiments, the present disclosure relates to a flexible magnetic resonance imaging (MRI) radio frequency (RF) array coil configured to operate in at least one of a transmit (Tx) mode or a receive (Rx) mode. The MRI RF array coil includes a first row of saddle coil elements. At least a first saddle coil element and a second saddle coil element are in the first row. The first and second saddle coil elements partially overlap with one another. Each of the first and second saddle coil elements include a left loop and a right loop that is coupled to the left loop by two connection segments.

Various embodiments of the present disclosure are directed to a magnetic resonance imaging (MRI) radio frequency (RF) coil comprising a current-control circuit. A conductive trace forms a coil inductor and comprises a first trace segment and a second trace segment separated by the current-control circuit, which comprises a first reactive element and a circuit branch. The first reactive element is electrically coupled from the first trace segment to the second trace segment, and the circuit branch is electrically coupled in parallel with the first reactive element. The circuit branch comprises a second reactive element and a sub-circuit branch electrically coupled in parallel. The sub-circuit branch comprises a third reactive element and an electronic switch (e.g., a PIN diode) electrically coupled in series. The first reactive element and the third reactive element are one of capacitive and inductive, and the second reactive element is another one of capacitive and inductive.

A method of designing a coil array for use in a magnetic resonance imaging (MRI) system based on eigenmode analysis of a scattering matrix associated with the coil array is provided. The method includes determining a normalized reflected power generated by coils in the coil array in response to excitation thereof via at least one excitation signal, and adjusting one or more parameters of at least one of the coils so as to minimize the normalized reflected power.

A head coil assembly includes a housing with a lower portion, an upper portion, a left portion, and a right portion, wherein each portion includes two or more radio-frequency (RF) coils, wherein the portions are sized and shaped to adjustably conform to a curvature of the subject's head for magnetic resonance (MR) imaging of the subject's head placed inside the housing, wherein the portions are operable to transition from an open position where the portions are sufficiently apart from each other to a closed position where the portions are adjusted to tighten a wrap around the subject's head along the curvature, and wherein the two or more RF coils in each portion are disposed in such manner that when the portions are operated to transition from the open position to the closed position, the RF coils of each portion remain decoupled to each other even along edges of each portion.

The present disclosure provides transmit/receive (T/R) systems for NMR or MRI systems. In one configuration, the systems and methods provided herein may use passively-shielded coils that are compatible with low-field operational environment to replace conventional T/R systems and spatial gradient systems. In some configurations, a low-field imaging T/R system is provided that is designed for nuclear magnetic stimulation and local flux sensitivity, while automatically rejecting incident radiant electromagnetic noise. The design advantageously leverages low required frequencies to distribute the pulse synthesis task, yielding a smaller system with easier maintenance and lower cost. The system may include distributed coil nodes that include a primary radiofrequency (RF) coil configured to transmit and receive RF signals and a secondary coil configured to passively shield the primary RF coil.

A preamplifier arrangement for an MRI system includes a preamplifier coupled to a loop of a multi-channel coil array of the MRI system, wherein the preamplifier and the loop are subject to potentially form an unstable system with oscillation at one or more peak frequencies. The preamplifier arrangement also includes an impedance matching network disposed between and coupled to the preamplifier and the loop. The impedance matching network is configured to generate a high blocking impedance. The preamplifier arrangement further includes an input network disposed between and coupled to the preamplifier and the loop. The input network is configured to provide an input to suppress gain at the one or more peak frequencies.

In some embodiments, the present disclosure relates to a flexible magnetic resonance imaging (MRI) radio frequency (RF) array coil configured to operate in at least one of a transmit (Tx) mode or a receive (Rx) mode. The MRI RF array coil includes a first row of saddle coil elements. At least a first saddle coil element and a second saddle coil element are in the first row. The first and second saddle coil elements partially overlap with one another. Each of the first and second saddle coil elements include a left loop and a right loop that is coupled to the left loop by two connection segments.

The exemplary system and method facilitate excitation of RF magnetic fields in ultra-high field (UHF) magnetic resonance (MRI) systems (e.g., MRI/NMR system) using a slotted waveguide array (SWGA) as an exciter coil. The exemplary exciter coil, in some embodiments, is configurable to provide RF magnetic field B.sub.1.sup.+ with high field-uniformity, with high efficiency, with excellent circular polarization, with negligible axial z-component, with arbitrary large field of view, and with exceptional possibilities for field-optimizations via RF shimming.

A method of operating a multi-coil magnetic resonance imaging system is disclosed which includes a controller performing a simulation using a predefined tissue model, determining output values of a variable of interest (VOI) associated with operation of two or more coils of an MRI system based on the simulation, comparing the simulated output values of the VOI to an a priori target values of the VOI, if the simulated output values of the VOI are outside of a predetermined envelope about the a priori target values of the VOI, then performing an optimization, wherein the optimization includes iteratively adjusting the circuit values until the simulated output values of the VOI are within the predetermined envelope about the a priori target values of the VOI thereby establishing VOI optimized values, and loading the established VOI optimized values and operating the magnetic resonance imaging system on the tissue to be imaged.