Abstract: A radiofrequency (RF) coil assembly (18,18?) for use in a magnetic resonance system (10) includes a radiofrequency coil (42) and a plurality of memory resistive elements (46,56,62,72) which each retains a selected resistive state after a control signal is removed. A detune circuit (44), part of the radiofrequency coil assembly, includes a memory resistive element (46) which switches the radiofrequency coil between a tuned and detuned state. Connected between the radiofrequency coil and a pre-amplifier (52), a blanking circuit (54) includes a memory resistive element (56) to short circuit an input of the pre-amplifier. A multiplexing circuit (60) includes a plurality of memory resistive elements (62) to selectively couple the selected outputs of the radiofrequency coils to a receiver (26).

Abstract: A magnetic resonance (MR) coil array (26, 28) connected by way of a single transmission line (46, 48) is provided. The MR coil array (26, 28) includes a coil element (34) and a corresponding coil element circuit (32). The coil element circuit (32) includes at least one active component (40) powered by a power signal carried on the coaxial transmission line (46, 48). The voltage of the power signal varies between first and second direct current (DC) voltages of the same polarity. The coil element circuit (32) further includes a tune/detune circuit (42) connected to the coaxial transmission line (46, 48). The tune/detune circuit (42) tunes or detunes the coil element (34) based on the first and second DC voltages. An MR system (10) using the MR coil array (26, 28) and a method (10) for tuning or detuning the MR coil (26, 28) are also provided.

Abstract: The exemplary embodiments are related to systems and methods for a mode balanced parametric amplifier. Exemplary embodiments relate to a balanced parametric circuit including a first resonant structure including a first plurality of varactor diodes and a second resonant structure including a second plurality of varactor diodes. The first and second resonant structures are coupled to form a coupled structure having at least two orthogonal resonant modes, where a first resonant mode is resonant at a first frequency of an input signal and a second resonant mode is resonant at a second frequency of a pump signal. Further, the pump signal is used to one of amplify the first signal at the first frequency or mix and amplify the first signal to a frequency higher than the first frequency.

Abstract: The invention discloses a decoupling circuit (32) disposed between adjacent RF receive coil elements to automatically decouple the adjacent MRI RF receive coil elements. In one embodiment, the invention involves to inject an RF signal into a first coil element, to measure the RF signal coupled from the first coil element into a second coil element and to adjust the capacitance of the decoupling circuit such as to minimize the coupling between the first and the second coil elements.

Abstract: A medical imaging system (34) includes a memory (45)and one or more processors (60). The memory (45)stores magnetic resonance k-space data (4)and the magnetic resonance data includes non-rigid motion defects. The one or more processors (60) are configured to reconstruct (6) a first image (8) from the magnetic resonance data (4) which includes a high signal to noise ratio and motion artifacts. The one or more processors are further configured to detect and reject (10) portions of k-space (4) which include non-rigid motion defects, and reconstruct (4) a second image (16) from non-rejected portions of k-space (12)and the first image (8).

Abstract: A preamplifier (46) comprises a field effect transistor (64) in common source configuration. While the gate of the field effect transistor is coupled to an amplifier input circuit (e.g. MRI coil), the drain of the field effect transistor (64) is coupled to an amplifier output. The preamplifier comprises furthermore a first (66) and a second (68) source-ground connection. The first source-ground lead (66) couples the source of the field effect transistor to the ground node of the amplifier input circuit, while the second source-ground lead (68) couples the source of the field effect transistor to the ground node of the amplifier output circuit. As a result, amplifier output currents generate basically a voltage drop across the second source-ground lead (68). Thus, the amplifier input circuit is less influenced by any common voltage drop across any common source-ground connection.

Abstract: The exemplary embodiments are related to systems and methods for a mode balanced parametric amplifier. Exemplary embodiments relate to a balanced parametric circuit including a first resonant structure including a first plurality of varactor diodes and a second resonant structure including a second plurality of varactor diodes. The first and second resonant structures are coupled to fom a coupled structure having at least two orthogonal resonant modes, where a first resonant mode is resonant at a first frequency of an input signal and a second resonant mode is resonant at a second frequency of a pump signal. Further, the pump signal is used to one of amplify the first signal at the first frequency or mix and amplify the first signal to a frequency higher than the first frequency.

Abstract: A magnetic resonance scanner (12) is configured for themographic imagin. One or more processors (28) receive (56) thermal image data from the magnetic resonance scanner and reconstruct at least one thermal image in which each voxel includes a measure of temperature change. The one or more processors identify (58) thermally abnormal voxels. A display (44) displays at least one reconstructed image with the identified abnormal thermal locations.

Abstract: A local radio frequency (RF) transmitting coil (26) of a magnetic resonance imaging system (5) has a plurality of coil elements (100). Each coil element (100) has an adjustable load (62) which is adjusted by a control unit (60) to adjust a transmitted B1 field distribution. The load can be adjusted to shim for a uniform B1 field distribution. Non-uniform B1 field distributions can be selected to perform magnetic resonance sequences that use such B1 field distributions, such as parallel imaging. The B1 field distribution can be changed during the magnetic resonance sequence to track a moving region of interest, time division multiplex parallel imaging, and the like.

Abstract: A magnetic resonance system includes a magnetic resonance scanner (8) and a magnetic resonance scan controller (24). A plurality of markers (40, 140) are attached to the subject to monitor motion of a portion of a subject within an examination region. A motion control unit receives motion data from the markers indicative of the motion and controls the magnetic scan controller to adjust scan parameters to compensate for the motion. In one embodiment, the marker (40) includes a substance (44) which resonates at a characteristic frequency in response to radio excitations by the magnetic resonance scanner. A controller (52) switches an inductive circuit (48, 50) disposed adjacent the substance between a tuned state and a detuned state. In another embodiment, the motion sensor includes an accelerometer, a gyroscope, a motion sensor, or a Hall-effect element, and a controller (144) which gathers motion data generated by the element and provides temporary storage for the motion data.

Abstract: A radiofrequency (RF) coil assembly for use in magnetic resonance includes a radiofrequency coil (42, 100) and an electronic switch (28) which switches between open and closed states to detune and tune the coil to a preselected resonance frequency. Each electronic switch includes at least one field effect transistor (FET) (70) and a bias network (72).

Abstract: A radiofrequency (RF) coil assembly (18,18?) for use in a magnetic resonance system (10) includes a radiofrequency coil (42) and a plurality of memory resistive elements (46,56,62,72) which each retains a selected resistive state after a control signal is removed. A detune circuit (44), part of the radiofrequency coil assembly, includes a memory resistive element (46) which switches the radiofrequency coil between a tuned and detuned state. Connected between the radiofrequency coil and a pre-amplifier (52), a blanking circuit (54) includes a memory resistive element (56) to short circuit an input of the pre-amplifier. A multiplexing circuit (60) includes a plurality of memory resistive elements (62) to selectively couple the selected outputs of the radiofrequency coils to a receiver (26).

Abstract: A preamplifier (46) comprises a field effect transistor (64) in common source configuration. While the gate of the field effect transistor is coupled to an amplifier input circuit (e.g. MRI coil), the drain of the field effect transistor (64) is coupled to an amplifier output. The preamplifier comprises furthermore a first (66) and a second (68) source-ground connection. The first source-ground lead (66) couples the source of the field effect transistor to the ground node of the amplifier input circuit, while the second source-ground lead (68) couples the source of the field effect transistor to the ground node of the amplifier output circuit. As a result, amplifier output currents generate basically a voltage drop across the second source-ground lead (68). Thus, the amplifier input circuit is less influenced by any common voltage drop across any common source-ground connection.

Abstract: A coaxial cable comprises at least one internal conductor and a surrounding cable shield. A plurality of sheath wave barriers are arranged along the cable shield, each having two ends that are coupled to the cable shield at coupling points of the cable shield that are spaced from one another. The coaxial cable is exposed to a radio-frequency excitation field with an excitation frequency, due to which sheath waves can be excited on the cable shield. The excitation field is shielded from the at least one internal conductor via the cable shield. The sheath waves can be damped via the sheath wave barriers. A detection circuit is associated with at least one of the sheath wave barriers, from which detection circuit a measurement signal characteristic of a load of the respective sheath wave barrier due to the excitation field can be generated. The measurement signal can be tapped and evaluated.

Abstract: An antenna for a magnetic resonance unit has a number of antenna rods arranged substantially regularly around an antenna axis, and being axially oriented relative to said antenna axis. Each antenna rod has two opposite ends with a central portion therebetween. The ends of each rod are electrically connected with the ends of at least one adjacent antenna rod by connecting elements oriented tangentially relative to the antenna axis. The rods are symmetrical relative to a plane of symmetry that proceeds perpendicularly relative to the antenna axis. Each point of each antenna rod defines a radial direction with the antenna axis, and the central portion defines a reference direction with respect to the antenna axis. Each radial direction forms a tangential angle with the reference direction, which is a non-constant function of the axial spacing of each point from the central portion of that rod.

Abstract: An antenna array has multiple individual antennas arranged next to one another. The individual antennas are respectively arranged within a radio-frequency, closed conductor loop, with capacitors inserted in each conductor loop.

Abstract: A local coil arrangement for a magnetic resonance system has an antenna arrangement that is arranged in a retainer structure. The retainer structure has a waistband and a perineum element. A person to be examined dons the local coil arrangement like trousers.

Abstract: A coil arrangement for a magnetic resonance apparatus has a number of coil elements that are capable of being operated independently of one another and are situated around a common central area. Each coil element of the coil arrangement is capacitively or inductively decoupled from the coil elements of the coil arrangement that are immediately adjacent to this coil element. In the central area, there is situated a capacitor network that connects the coil elements of the coil arrangement to one another. The capacitor network is fashioned and dimensioned such that it at least reduces the coupling of each coil element of the coil arrangement to at least one additional coil element of the coil arrangement that is not immediately adjacent to the respective coil element.

Abstract: An antenna for a magnetic resonance unit has a number of antenna rods arranged substantially regularly around an antenna axis, and being axially oriented relative to said antenna axis. Each antenna rod has two opposite ends with a central portion therebetween. The ends of each rod are electrically connected with the ends of at least one adjacent antenna rod by connecting elements oriented tangentially relative to the antenna axis. The rods are symmetrical relative to a plane of symmetry that proceeds perpendicularly relative to the antenna axis. Each point of each antenna rod defines a radial direction with the antenna axis, and the central portion defines a reference direction with respect to the antenna axis. Each radial direction forms a tangential angle with the reference direction, which is a non-constant function of the axial spacing of each point from the central portion of that rod.

Abstract: A radio-frequency antenna for acquisition of a magnetic resonance signal has two electrodes that are connected with one another via a discrete tuning device. The first radio-frequency antenna) is tuned to a resonance frequency by the tuning device. The tuning device has a first tuning element influencing the resonance frequency of the radio-frequency antenna and a second tuning element influencing the resonance frequency of the first radio-frequency antenna. The tuning elements are connected in series and fashioned as inductors. The radio-frequency antenna also has two tap points at which an acquisition signal representative of the acquired magnetic resonance signal is tapped and conducted away via feed lines. The tap points are respectively arranged between the electrodes and the tuning element and one of said tap points is between the first and second tuning elements.