Patent classifications
G01R33/34076
ROTATING MRI COILS FOR SAFE IMAGING OF PATIENTS WITH ELECTRONIC IMPLANTS
A system to perform magnetic resonance imaging includes a transmit coil that has a plurality of transmitters. The transmit coil is configured to receive at least a portion of an implant that is within a pediatric patient. The system also includes a controller operatively coupled to the transmit coil. The controller is configured to identify a region within the transmit coil with zero electric field while the transmitters are transmitting. The controller is also configured to rotate the transmit coil around the pediatric patient such that the implant is located within the region with zero electric field to avoid radio frequency heating of the implant.
Acoustic noise reducing RF coil for magnetic resonance imaging
An RF coil assembly for use in a Magnetic Resonance Imaging scanner incorporates sound absorbing material in its construction for the purpose of attenuating the sound perceived by a patient lying inside the RF coil. Unlike a conventional RF coil assembly in which rigid components are used to support the coil within the magnet bore, the quiet RF coil assembly is constructed without rigid support components. In one embodiment, open cell foam may be used to support the RF coil components and the entire assembly is wrapped in a. flexible cloth-like material.
Plasma Thruster With Birdcage Antenna
A plasma thruster comprises a cylindrical discharge channel (1), an injector (4), a RF antenna surrounding the discharge channel (1) and a device (3) for generating an axial static magnetic field in the discharge channel (1). The RF antenna is a cylindrical birdcage antenna (2) formed of several electrically conductive parallel legs (10) connected by two end rings (11) including capacitors (12) between adjacent legs (10) in each case. The two end rings (11) with the capacitors (12) are formed on two printed circuit boards (14) to which the legs (10) are attached, said printed circuit boards (14) having a through opening for the discharge channel (1). The antenna maximizes electrical coupling efficiency and provides resulting electromagnetic fields for quasi-neutral plasma acceleration along with the magnetic field effect provided by the externally applied magnetic field. This plasma thruster allows an easy upscaling or downscaling due to the printed circuit boards and is particularly suitable for low power applications like propulsion for smaller spacecrafts or satellites.
MONITORING AN ABSORPTION RATE OF INDUCTIVELY COUPLED COILS
The disclosure relates to a method for monitoring an absorption rate when using a primary coil of a magnetic resonance device and a secondary coil inductively coupled to the primary coil and to a monitoring unit, a magnetic resonance device and a computer program product. According to the method a maximum admissible absorption rate is provided, using which a maximum admissible B1 field strength of the secondary coil is determined. Furthermore, an actual B1 field strength of the secondary coil is determined. The absorption rate is monitored using the actual B1 field strength of the secondary coil and the maximum admissible B1 field strength of the secondary coil.
MR antenna with compensation for variable distance to shield
A whole-body coil for a magnetic resonance tomography device includes one or more compensation capacitors between a high-frequency antenna and an RF shield. The one or more compensation capacitors each have variable capacitance caused by a variation in a distance of the RF shield to the high-frequency antenna.
Systems and methods for volumetric acquisition in a single-sided MRI scanner
A method for performing magnetic resonance imaging is provided. The method includes providing a magnetic resonance imaging system comprising: a radio frequency receive system comprising a radio frequency receive coil, and a housing, wherein the housing comprises a permanent magnet for providing an inhomogeneous permanent gradient field, a radio frequency transmit system, and a single-sided gradient coil set. The method also includes placing the receive coil proximate a target subject; applying a sequence of chirped pulses via the transmit system; applying a multi-slice excitation along the inhomogeneous permanent gradient field; applying a plurality of gradient pulses via the gradient coil set orthogonal to the inhomogeneous permanent gradient field; acquiring a signal of the target subject via the receive system, wherein the signal comprises at least two chirped pulses; and forming a magnetic resonance image of the target subject.
Transmission arrangement for a tomograph
A transmission arrangement for a tomograph, such as magnetic resonance tomography, is provided for wireless energy supply of a local coil system. The transmission arrangement includes at least one first region having at least one first antenna element. The transmission arrangement further includes at least one second region having at least one second antenna element. The at least one first region and the at least one second region are connected to one another via at least one rejector circuit.
Method and apparatus for determination of a magnetic resonance system control sequence
In a method and a control sequence determination device for determining a magnetic resonance system control sequence includes at least one radio-frequency pulse train to be emitted by a magnetic resonance system, a target magnetization is acquired and a k-space trajectory is determined. A radio-frequency pulse train for the k-space trajectory is then determined in an RF pulse optimization method using a target function, wherein the target function includes a combination of different trajectory curve functions, of which at least one trajectory curve function is based on a trajectory error model. A method for operating a magnetic resonance system uses such a control sequence and a magnetic resonance system has such a control sequence determination device.
Integrated active detuning for magnetic resonance imaging
A coil assembly includes: a radio frequency (RF) coil operable to be placed over a portion of a subject; a quarter-wave transformer coupled to the RF coil and configured to transform a characteristic impedance of the RF coil; and a diode placed behind the quarter-wave transformer and away from the RF coil, wherein the diode is operable to: (i) when the diode is forward biased, the diode turns the quarter-wave transformer into an open circuit such that the power amplifier drives the RF coil with sufficient electrical power for the RF coil to transmit an RF pulse into the portion of the subject; and (ii) when the diode is provided zero or revers bias, the diode turns the quarter-wave transformer into a short circuit such that the RF coil is detuned from a Lamor frequency of nuclei of interest immersed in the main magnet.
Method and device for controlling a magnetic resonance imaging apparatus
Starting with a magnetic resonance imaging system control sequence that has a radio-frequency (RF) pulse train to control the RF transmission system and a gradient pulse train, chronologically matching the RF pulse train, to control the gradient system, the gradient pulse train including a predetermined selection gradient pulse chronologically matched to a refocusing pulse of the RF pulse train, the execution capability of the control sequence is initially established using an execution capability criterion, in particular under consideration of a refocusing flip angle of the refocusing pulse. Modification of the refocusing pulse and/or of the selection gradient pulse takes place depending on the establishment of the execution capability of the control sequence.