The present invention provides a passive radio frequency (RF) shim resonator (144) for field homogenization of an RF field emitted by an RF antenna device (140) of a magnetic resonance (MR) imaging system (110), whereby the passive RF shim resonator (144) has a first resonating capability and a second resonating capability, and the passive RF shim resonator (144) comprises a switching device, whereby the switching device is adapted to switch between the first and the second resonating capability in accordance with a TX- mode and a RX-mode of the RF field emitted by the RF antenna device (140) of the MR imaging system (110). The present invention further provides a patient bed (142) or a patient mattress for use in a magnetic resonance imaging (MRI) system (110), whereby the patient bed (142) or the patient mattress comprises an above passive RF shim resonator (144). The present invention further provides a RF antenna device for generating and/or receiving a RF field for use in a MRI system (110), whereby the RF antenna device (140) comprises a coil housing and an above passive RF shim resonator (144), wherein the passive RF shim resonator (144) is located within the coil housing. The present invention also provides a magnetic resonance (MR) imaging system (110), comprising an above patient bed (142) or patient mattress or at least one above RF antenna device (140).

A method for producing a streak-suppressed magnetic resonance (MR) image of a subject includes generating an interference covariance matrix {circumflex over ( )}R front N coil images Ij (x,y), j={1, 2, . . . , N}, each of the N coil images Ij (x,y) corresponding to MR signals detected by a respective one of a phased array of N coils of an MRI scanner. The MR signals originate in voxels of the subject corresponding to an artifact-corrupted region of a coil image. Coordinates (x,y) correspond to a location within a cross-sectional plane of the subject. The method also includes, for subject-regions of cross-sectional plane centered at a respective location (x,y), determining a coil weight vector W (x,y) from {circumflex over ( )}R. The method also includes generating the streak-suppressed MR image as a weighted sum of the coil images Ij (x,y), each weight of the weighted sum being Wj* (x,y), a j.sup.th element of a complex conjugate of coil weight vector W (x,y).

A magnetic resonance tomography scanner and a method for testing the magnetic resonance tomography scanner are provided. The magnetic resonance tomography scanner has a transmitter that is configured to transmit two-tone signals at different levels and to acquire intermodulation products of the two-tone signal with the receiver. A status of a receive path is inferred via a behavior of odd-order intermodulation products.

A radio frequency (RF) antenna element with a (de)tuning system, with the RF antenna element having a resonant electrically conductive loop and a (de)tuning system including a photosensitive switching element to (de)tune the resonant electrically conductive loop. The (de)tuning system comprises an injection optical source optically coupled to the photosensitive switching element.

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.

In a method, device and digital receiver for transmitting signals in magnetic resonance imaging, M channels of digital signals are received over M receiving channels from a digital matrix processor. One receiving channel corresponds to one channel of digital signal and the M channels of digital signals include one channel of main signal and (M1) channels of high-order signals. The M channels of digital signals are combined into N channels of combined signals, wherein the main signal and at least one channel of high-order signal are combined into one channel of combined signal, or at least two channels of high-order signals are combined into one channel of combined signal. N and M are both positive integers, N is less than M, and M is greater than or equal to 2.

A magnetic resonance (MR) imaging system includes a transmit radio frequency (RF) coil assembly comprising multiple capacitor banks each coupled to at least one diode that is characterized by a high breakdown voltage such that when the transmit RF coil assembly applies at least one slice-selecting RF pulse to a portion of a subject placed in the magnet to select a particular slice for MR imaging, the capacitor banks are selectively adjusted to improve an RF transmission characteristics of the RF coil assembly in transmitting the at least one slice-selecting RF pulse. The MR imaging system may further include a receive radio frequency (RF) coil assembly configured to, in response to at least the slice-selecting RF pulse, receive at least one response radio frequency (RF) pulse emitted from the selected slice of the portion of the subject; a housing; a main magnet; gradient coils; and a control unit.

A dual frequency coil package system for use in transmitting and receiving at least two frequencies in an MRI system, including a frequency converter coupled to the MRI system to receive a first frequency through the local transmit coil port and convert the first frequency to a second frequency, a second frequency transmit coil to receive the second frequency from the frequency converter and to transmit the second frequency, a dual tuned receiver coil to receive and to output the at least two frequencies, and a switchable receiver to receive the at least two frequencies output from the dual tuned receiver coil and to transmit the first frequency received from the dual tuned receiver coil directly to the MRI system, and to convert the second frequency received from the dual tuned receiver coil to the first frequency before transmission to the MRI system.

A local coil matrix and a method are provided for image acquisition with a magnetic resonance tomography unit. The local coil matrix includes a plurality of coil windings. In magnetic resonance imaging, a predetermined region of a patient arranged in the vicinity of the local coil with selectable differently-sized sensitivity ranges is acquired and/or excited. An image is reconstructed from the magnetic resonance signals acquired with the local coil matrix.

Various methods and systems are provided for selecting radio frequency (RF) coil array for magnetic resonance imaging (MRI). In one embodiment, the method comprises grouping the plurality of coil elements into receiving 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, selecting one or more REGs based on the REG sensitivity maps and a region of interest (ROI), and scanning the ROI with the coil elements of the one or more selected REGs being activated and the coil elements not in any selected REGs being deactivated. In this way, coil arrays may be automatically selected for improved image quality of the MRI.