Abstract: A method and apparatus are provided for limiting a B1 field used for magnetic resonance imaging (MRI). The techniques described herein reduce a waste of performance of the B1 field while ensuring patient safety and improving the MR imaging quality.

Abstract: The present disclosure relates to techniques for monitoring an operating state of a birdcage coil in a magnetic resonance system. The birdcage coil comprises a pair of end rings, and multiple legs arranged between the pair of end rings and connected to the pair of end rings. The technique enables a determination that an open circuit has occurred in at least one of the multiple legs.

Abstract: A method and apparatus for limiting an RF alternating magnetic field in MRI. The method includes: measuring a perpendicular distance between a local coil placed on a scanned part of a patient and the center of a detection hole of a magnetic resonance (MR) scanner; based on the perpendicular distance, determining a deviation between the B1 field strength at the position of the local coil during an MR scan and the B1 field strength at the center of the detection hole; based on the deviation, computing a conversion coefficient for conversion between the B1 field strength at the position of the local coil and the B1 field strength at the center of the detection hole; based on the B1 field strength required when the surface temperature of the local coil is equal to a safe temperature upper limit and the conversion coefficient, computing a maximum permissible field strength of the B1 field at the center of the detection hole.

Abstract: A method and apparatus are provided for limiting a B1 field used for magnetic resonance imaging (MRI). The techniques described herein reduce a waste of performance of the B1 field while ensuring patient safety and improving the MR imaging quality.

Abstract: A method and apparatus for limiting an RF alternating magnetic field in MRI. The method includes: measuring a perpendicular distance between a local coil placed on a scanned part of a patient and the center of a detection hole of a magnetic resonance (MR) scanner; based on the perpendicular distance, determining a deviation between the B1 field strength at the position of the local coil during an MR scan and the B1 field strength at the center of the detection hole; based on the deviation, computing a conversion coefficient for conversion between the B1 field strength at the position of the local coil and the B1 field strength at the center of the detection hole; based on the B1 field strength required when the surface temperature of the local coil is equal to a safe temperature upper limit and the conversion coefficient, computing a maximum permissible field strength of the B1 field at the center of the detection hole.

Abstract: A coil assembly, an MRI system, and a method of using the coil assembly. The coil assembly includes: a flexible coil configured to cover a tissue under test in a wound fashion; a pressure adjuster configured to be integrated with the flexible coil, for the purpose of applying uniform pressure to the entire flexible coil such that the flexible coil fits the covered tissue under test; a pressure controller configured to control the pressure applied to the flexible coil by the pressure adjuster; and a connection member, constructed to connect the pressure controller to the pressure adjuster.

Abstract: A local shimming device and a method for compensation of non-uniformity of a main magnetic field are disclosed, wherein the local shimming device comprises: a local coil, arranged to cover a local region of an examination subject, to receive a magnetic resonance signal from the local region; multiple shim coils, wherein the multiple shim coils are integrated in the local coil or arranged to surround at least a part of the local coil; and a shimming controller, configured to control at least one shim coil of the multiple shim coils, according to a strength distribution of a main magnetic field in the local region, to provide a field distribution for compensating a component of the main magnetic field in the local region.

Abstract: A tuning/detuning structure and a detuning method for an RF coil use an RF power source, a first impedance circuit, a first RF line, and a first port having a first guide leg end and a first input end, with the first guide leg end being connected to a first end ring capacitance of the RF coil. When the RF coil needs to be detuned, the first input end is connected to the first impedance circuit via the first RF line. When the RF coil needs to transmit an RF pulse signal, the first input end is connected to the RF power source via the first RF line. The need for a switch element is thereby reduced as is harm resulting from breakdown of such a switch element. An impedance circuit can be combined with a switch element to realize detuning jointly, and a good detuning effect can be achieved by a small number of switch elements.

Abstract: A tuning/detuning structure and a detuning method for an RF coil use an RF power source, a first impedance circuit, a first RF line, and a first port having a first guide leg end and a first input end, with the first guide leg end being connected to a first end ring capacitance of the RF coil. When the RF coil needs to be detuned, the first input end is connected to the first impedance circuit via the first RF line. When the RF coil needs to transmit an RF pulse signal, the first input end is connected to the RF power source via the first RF line. The need for a switch element is thereby reduced as is harm resulting from breakdown of such a switch element. An impedance circuit can be combined with a switch element to realize detuning jointly, and a good detuning effect can be achieved by a small number of switch elements.

Abstract: A magnetic resonance signal receiving apparatus has a local coil, and an RF receiver connected thereto the local coil via a plug. The local coil has multiple antenna units, each separately receiving magnetic resonance signals generated by a subject in a magnetic resonance examination. The local coil also has a respective bandpass filter for each antenna unit. The local coil also has a time division multiplexer having multiple input ports respectively connected to the bandpass filters. Bandpass-filtered magnetic resonance signals that have passed through the bandpass filters are thus emitted as an output by just one output line according to multiplexing timeslot. The RF receiver has one or more RF receiving channels for receiving and processing the magnetic resonance signal from the output line of the local coil. The RF receiver is disposed close to the plug.

Abstract: A receiving coil for a magnetic resonance system includes an antenna unit and a locating unit. The locating unit is used for locating a subject to be examined and is positioned inside the antenna unit. The receiving coil for a magnetic resonance system may improve a patient's level of comfort, reduce the complexity of operation, and improve the coil's signal-to-noise ratio.