Method and control device for determination of the position of a local coil in a magnetic resonance apparatus

A control device configured for determining a position of a local coil on a bed within a magnetic resonance scanner that is movable relative to the magnetic resonance scanner, said local coil being placed at a position on the patient bed, said position initially being unknown to the processor of the magnetic resonance scanner, said control device being configured to:

• move said bed together with said local thereon through a plurality of positions relative to said scanner;
• at each of said plurality of positions, operate said magnetic resonance scanner to excite nuclear spins in an examination subject on the bed using a transmitting antenna other than said local coil to cause magnetic resonant signals to be generated in the subject, and also at each of said plurality of positions, detect said magnetic resonance signals with said local coil to obtain respective magnetic resonance measurement signals;
• extract a signal intensity value for said local coil from said magnetic resonance measurement signals and determine a dependency of the extracted signal intensity values on the respective positions of the bed relative to the scanner;
• and
• from the determined dependency, identify a position, in at least one spatial direction, of the local coil on the bed and generate a signal, in a form selected from the group consisting of a stored signal and a signal emitted from the control device, representing said position in a form suitable for use in image acquisition or image reconstruction.

A magnetic resonance system comprising:

• a magnetic resonance scanner;
• a patient bed that is movable relative to the magnetic resonance scanner;
• a processor;
• a local coil on said patient bed that is moveable with said patient bed in said scanner;
• a transmitting antenna other than said local coil;
• said local coil being at a position on the patient bed, said position initially being unknown to the processor of the magnetic resonance scanner;
• said processor being configured to move said bed together with said local coil thereon through a plurality of positions relative to said scanner;
• said processor being configured to operate said magnetic resonance scanner to excite at each of said plurality of positions, nuclear spins in an examination subject on the bed using the transmitting antenna other than said local coil to cause magnetic resonant signals to be generated in the subject, and also at each of said plurality of positions, to detect said magnetic resonance signals with said local coil to obtain respective magnetic resonance measurement signals;
• said processor being configured to extract a signal intensity value for said local coil from said magnetic resonance measurement signals and configured to determine a dependency of the extracted signal intensity values on the respective positions of the bed relative to the scanner;
• and
• said processor being configured to identify, from the determined dependency, a position, in at least one spatial direction, of the local coil on the bed and to generate a signal, in a form selected from the group consisting of a stored signal and a signal emitted from the processor, representing said position in a form suitable for use in image acquisition or image reconstruction.

A computer-readable medium that determines a position of a local coil on a bed within a magnetic resonance scanner that is movable relative to the magnetic resonance scanner, said magnetic resonance scanner also comprising a processor, said local coil being at a position on the patient bed, said position initially being unknown to the processor of the magnetic resonance scanner, said computer-readable medium being encoded with programming instructions that cause said processor to:

• move said bed together with said local thereon through a plurality of positions relative to said scanner;
• at each of said plurality of positions, operate said magnetic resonance scanner to excite nuclear spins in an examination subject on the bed using a transmitting antenna other than said local coil to cause magnetic resonant signals to be generated in the subject, and also at each of said plurality of positions, to detect said magnetic resonance signals with said local coil to obtain respective magnetic resonance measurement signals;
• in said processor, extract a signal intensity value for said local coil from said magnetic resonance measurement signals and determine a dependency of the extracted signal intensity values on the respective positions of the bed relative to the scanner;
• and
• in said processor, from the determined dependency, identify a position, in at least one spatial direction, of the local coil on the bed and generate a signal, in a form selected from the group consisting of a stored signal and a signal emitted from the processor, representing said position in a form suitable for use in image acquisition or image reconstruction.