Siemens Healthineers Ag

Siemens Healthcare Gmbh

Ying Lun Wang

Zhi Bin Li

Qiu Yi Zhang

Jianmin Wang

Juergen Nistler

Wen Ming Li

Hou Quan Lin

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.

Method and apparatus for limiting radio frequency alternating magnetic field in magnetic resonance imaging

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 Bfield strength at the position of the local coil during an MR scan and the Bfield strength at the center of the detection hole; based on the deviation, computing a conversion coefficient for conversion between the Bfield strength at the position of the local coil and the Bfield strength at the center of the detection hole; based on the Bfield 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 Bfield at the center of the detection hole. The Bfield may be limited to a smaller but still effective field strength range, reducing wastage of Bfield performance while ensuring patient safety and MR imaging quality.

Limiting RF alternating magnetic field in MRI

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.

Tuning/detuning circuit and detuning method for an RF coil

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Shenzhen, China

Ying Lun Wang