Various systems are provided for magnetic resonance imaging (MRI). In one example, a method includes selecting a contour topology for operating a configurable radio frequency (RF) coil assembly, wherein the configurable RF coil assembly includes an array of conductive segments coupled via a plurality of switches, and the contour topology defines a configuration of one or more RF coil elements formed on the configurable RF coil assembly. The method further includes, during a receive mode, at least partially activating one or more subsets of switches of the plurality of switches according to the selected contour topology to form the one or more RF coil elements.

An example magnetic resonance imaging (MRI) radio frequency (RF) coil array comprises: at least one row of RF coil elements arranged radially around a cylindrical axis, wherein each row comprises: at least four RF coil elements circumferentially enclosing the cylindrical axis, wherein each RF coil element of that row is configured to operate in a Tx mode and in a Rx mode, wherein, in the Rx mode, each RF coil element of that row is tuned to a working frequency of the MRI RF coil array, and wherein, in the Tx mode, each RF coil element of that row is tuned to an additional frequency that is different than the working frequency, wherein the additional frequency is such that, a mode frequency of a selected mode resulting from coupling among the RF coil elements of that row is at the working frequency.

Various methods and systems are provided for selecting coil elements of a plurality of coil elements of a radio frequency (RF) coil array for use in a magnetic resonance imaging (MRI) system. In one example, a method includes grouping the plurality of coil elements into receive elements groups (REGs) according to REGs information, generating channel sensitivity maps for the plurality of coil elements, generating REG sensitivity maps based on the REGs information and the channel sensitivity maps, labeling each REG as either selectable or not selectable based on the REG sensitivity maps, selecting one or more REGs from the selectable REGs based on the REG sensitivity maps and a region of interest (ROI), and scanning the ROI with the coil elements in the one or more selected REGs being activated and the coil elements not in any selected the other REGs being deactivated.

Various methods and systems are provided for selecting radio frequency coil array comprising a plurality of coil elements for magnetic resonance imaging. In one embodiment, the method includes grouping the plurality of coil elements into receive elements groups (REGs) according to REGs information; generating REG sensitivity maps; determining, for each REG, signal in a region of interest (ROI) and signal in an annefact source region based on the REG sensitivity maps; selecting one or more REGs based on the signal in the ROI and the signal in the annefact source region; and scanning the ROI with the coil elements in the one or more selected REGs being activated and the coil elements not in any selected REGs being deactivated. In this way, annefact artifacts in the reconstructed image may be reduced.

A coil facility for a magnetic resonance installation and a magnetic resonance installation having such a coil facility are provided. The coil facility in this case includes a double-resonant transmit resonator for two frequencies and a first receiver and a second receiver, each for one of the two frequencies. The coil facility has an actuator system for effecting a relative spatial transposition of the transmit resonator, the first receiver, and the second receiver into various settings. In a first setting, only the first receiver, and in a second setting, only the second receiver, for receiving corresponding MR signals is arranged in an examination space that is at least sectionally surrounded by the transmit resonator.

An MRI RF coil array for use in a multi-channel MRI system, comprising a plurality of coils arranged in a M by N array, the number of columns corresponding with the number of channels in the MRI system. Columns are aligned with the B.sub.0 field. The plurality of coils are configured as a plurality of combined coils, corresponding with the number of columns, comprising a coil in a first row of the array connected with a coil in each of the remaining rows. The column position of each coil of a combined coil is distinct from the column position of each other coil of the combined coil. Coils of a combined coil are disjoint from the coils of each, other, combined coil. A combined coil is configured to connect with a corresponding member of the plurality of Rx channels, and is decoupled from each, other combined coil.

A method includes capturing a first set of optical images of the subject while a subject is lying on a table of a Magnetic Resonance (MR) scanner. This first set of optical images is acquired without any MR phased-array coils placed on the subject. While the subject continues to lie on the table of the MR scanner, a second set of optical images of the subject is acquired with the MR phased-array coils placed on the subject. Aside from the optical images, a set of MR images of the subject is acquired using the MR scanner. The first and second set of optical images are registered to the MR images. Following registration, the first and second set of optical images are used to determine element positioning of the MR phased-array coils in the set of MR images.

A digital mode matrix phase calibration includes acquiring an actual phase deviation .sub.mn forming an actual phase deviation matrix of a factory system; calculating an ideal phase deviation forming an ideal phase deviation matrix; calculating a phase deviation of the actual phase deviation and the ideal phase deviation; acquiring a maximum value of the phase deviation; when the maximum value .sub.max is less than a preset threshold , calculating a field system phase deviation .sub.mn, and a field system phase deviation matrix formed by the field system phase deviation .sub.mn subjecting a field system to phase calibration. By acquiring only one row and one column in the phase deviation matrix, the technical solution in embodiments of the present invention can fit phase deviations of other rows and columns, and the method subjects the system to phase calibration quickly.

Provided is a radio frequency antenna receiving method and device for a downhole three-dimensional scanning nuclear magnetic resonance imager. The device comprises: an array antenna for receiving an echo signal, an antenna interface circuit, a receiving and amplifying circuit for amplifying the echo signal, an analog-to-digital conversion circuit, a signal collecting circuit and a control circuit, which are sequentially connected; the array antenna comprises N antenna units, where N4; four ports of the control circuit are respectively connected to the antenna interface circuit, the receiving and amplifying circuit, the analog-to-digital conversion circuit and the signal collecting circuit so as to control them, and the control circuit is connected to a logging ground acquisition system; the antenna interface circuit selects one antenna unit in the array antenna. The method and device of the present invention can perform signal detection in a circumferentially multi-directional sensitive region.

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.