Abstract: A local coil for a magnetic resonance tomography system is provided. The local coil has a coil winding and a preamplifier connected electrically thereto. The coil winding has a plurality of coil segments that are coupled capacitively to one another.

Abstract: A magnetic resonance tomography unit and a method for operating the magnetic resonance tomography unit are provided. The magnetic resonance tomography unit includes a transmitter for generating excitation pulses with a wavelength lambda, an antenna for emitting the excitation pulses, a feed line, and a voltage sensor. The voltage sensor is arranged on the feed line at an effective distance corresponding to a multiple of half the wavelength lambda from a feed point on the antenna.

Abstract: The disclosure relates to a medical image acquisition device with a pilot tone transmitter and a pilot tone receiver and to a method for operating the same. The pilot tone transmitter is configured to emit an electromagnetic radio frequency signal into a patient. The pilot tone receiver is configured to receive the radio frequency signal and to decode an item of information relating to a physiological process in the patient. The pilot tone transmitter has a modulator configured to modulate the electromagnetic radio frequency signal with a code and the pilot tone receiver is configured to select the modulated radio frequency signal using the encoding from a plurality of signals.

Abstract: A device for recovering a temporal reference in a free-running magnetic resonance tomography (MRT) receive chain includes a time reference encoder and a time reference decoder. The time reference encoder is configured to generate a modulation signal as a function of a reference clock, where the modulation signal is configured for a correlation with a temporal resolution less than a maximum predetermined phase deviation and a maximum that may clearly be identified. The time reference decoder is configured to receive, via the first signal input, a receive signal as a function of the modulation signal, perform a correlation with a reference signal, and generate a signal as a function of a temporal reference of the modulation signal in the receive signal in relation to the reference signal.

Abstract: A method for monitoring a temporal change in a magnetic field in a magnetic resonance device, as well as an evaluation unit, a magnetic resonance device, and a computer program product for performing the method are provided. The method provides that a position-dependent magnetic field distribution that is produced by the plurality of gradient coils is provided with a plurality of monitoring points. In addition, time-dependent gradient values of the plurality of gradient coils are ascertained. Based on position-dependent magnetic field distribution and the time-dependent gradient values, the temporal change in the magnetic field is ascertained. The temporal change in the magnetic field is monitored by comparing the temporal change in the magnetic field with at least one limit value.

Abstract: The disclosure relates to a local coil with a device for providing a first mixed frequency signal and a second mixed frequency signal by a first auxiliary frequency signal and a second auxiliary frequency signal. The device has an auxiliary mixer configured to generate the second mixed frequency signal from the first auxiliary frequency signal and the second auxiliary frequency signal. The local coil has a signal input including a first signal connection to the device. The local coil is configured to jointly receive the first auxiliary frequency signal and the second auxiliary frequency signal by way of the signal input and supply them to the device by way of the first signal connection.

Abstract: Method and system for cleaning a magnetic resonance measurement dataset. In the method, a GRAPPA kernel is calibrated on the measurement dataset, k-space values of the measurement dataset are verified against a predefined intensity criterion in order to identify false values, the k-space values of the measurement dataset are reconstructed point-by-point using the calibrated GRAPPA kernel from respective others of the k-space values, and the false values are replaced with the corresponding reconstructed k-space values in order to generate a cleaned measurement dataset.

Abstract: A method of operating a magnetic resonance imaging (MRI) apparatus includes exciting a body coil of the MRI apparatus to emit a radio-frequency signal, determining a center frequency of a resonance curve of the body coil, and calculating a magnet target frequency based on the determined center frequency. A magnet is ramped to the magnet target frequency.

Abstract: A radio-frequency shielding unit for shielding a radio-frequency antenna unit of a magnetic resonance apparatus and a magnetic resonance apparatus are provided. The radio-frequency shielding unit includes a support layer, a first conducting layer, an insulating layer, and a second conducting layer. The first conducting layer is arranged between the support layer and the insulating layer, and the insulating layer is arranged between the first conducting layer and the second conducting layer.

Abstract: A magnetic resonance tomography unit includes a control unit, a transmitting unit having one or a plurality of transmitting antennae, a selector, and a high-frequency unit having a signal output in signal connection with the transmitting unit. The transmitting unit is configured to irradiate high-frequency energy using the selector and the one or plurality of transmitting antennae optionally into only a first region of a plurality of different regions in a patient.

Abstract: The invention relates to a local coil matrix and to a magnetic resonance scanner for operation by means of a low magnetic field. The local coil matrix according to the invention has a first coil winding and a second coil winding and a first low-noise pre-amplifier and second pre-amplifier, each electrically connected to a coil winding. The first coil winding has a broadband matching in a first frequency range at a Larmor frequency to the first pre-amplifier connected thereto.

Abstract: A radio-frequency system for a magnetic resonance apparatus has a local coil, a body coil, and an impedance adjusting shield. The body coil is wirelessly power-coupled with the local coil such that the body coil serves as a transmitting coil for radio-frequency signals and the local coil serves as a receiving coil for magnetic resonance signals. The local coil is disposed in an internal cavity of the impedance adjusting shield. An impedance of the local coil is adjusted by the impedance adjusting shield so as to match the impedance of the local coil and the body coil. The impedance adjusting shield has a frequency modulation element that adjusts the resonance frequency of the local coil. The body coil couples power to the local coil, and the impedance adjusting shield effectively reduces energy transmission efficiency loss caused by reflection, thereby improving energy transmission efficiency.

Abstract: A method for correcting a B0 inhomogeneity in a magnetic resonance scan with a magnetic resonance tomograph is provided. The magnetic resonance tomograph includes a controller, a radio frequency unit, and a transmitting antenna. In the method, the controller determines a transmission signal that is suitable for correcting an effect of an inhomogeneity of a static B0 magnetic field in an examination volume by the Bloch-Siegert effect. The transmission signal is emitted into the examination volume.

Abstract: An apparatus and a method for spatial encoding in magnetic resonance tomography using a radio frequency signal are provided. A first set of parameters from a first frequency and from a first amplitude, and from a second frequency and a second amplitude is determined by the magnetic resonance tomograph, and corresponding signals are generated by a radio frequency device and transmitted by an antenna apparatus. A first gradient above the Larmor frequency of the nuclear spins is generated by the Bloch-Siegert effect. The same thing ensues with a second set of parameters that differs from the first set of parameters at least in one frequency or amplitude and therefore generates a second, different gradient.

Abstract: A transmitter for pilot tone navigation in a magnetic resonance tomography system includes a power supply and an antenna. The transmitter is configured to transmit a pilot tone signal via the antenna. The transmitter also includes a decoupling element in order to protect a transmitter output from signals that the antenna receives with excitation pulses of the magnetic resonance tomography system during a magnetic resonance tomography. In a method, movement-dependent changes to the pilot tone signal of the transmitter are identified by a controller of the magnetic resonance tomography system.

Abstract: A local coil for a magnetic resonance tomography system is provided. The local coil has a coil winding and a preamplifier connected electrically thereto. The coil winding has a plurality of coil segments that are coupled capacitively to one another.

Abstract: An apparatus and a method for detecting an antenna coil with a non-active detuning apparatus are provided. The apparatus has a transmitter, an antenna, an amplitude meter, and a controller. The controller actuates the transmitter such that the transmitter emits radio-frequency signals with different predetermined amplitudes via the antenna. The controller acquires testing amplitudes with the amplitude meter as a function of the emitted signal and determines a testing relationship between the predetermined amplitudes and the acquired testing amplitudes. If the determined testing relationship deviates from a predetermined reference relationship, a signal is output.

Abstract: A body coil for an MRI system has a conductor management and a tuning/detuning circuit. The tuning/detuning circuit is connected to the conductor management, and used to subject the conductor management to tuning/detuning control by a control signal. The tuning/detuning circuit has a control signal interface, a switch diode unit and an AC/DC conversion circuit. The control signal interface receives the control signal. There is at least one switch diode unit, respectively series-connected on at least one antenna rod and/or at least one end ring of the body coil conductor management. The AC/DC conversion circuit has a rectifying circuit, for converting the power of an input RF emission signal in the MRI system to a DC current, the DC current being used to provide a DC current for the switch diode unit to be turned on. The body coil reduces the cost of a DC power supply, and this reduces heat generated by the diodes.

Abstract: A method of determining a decoupling matrix of a decoupling system for an array of coils of a parallel transmission magnetic resonance imaging (MRI) system includes obtaining impedance matrix data for the array of coils without the decoupling system, determining, based on the impedance matrix data for the array of coils, an objective function representative of deviation from a decoupled operating condition for the array of coils in which the array of coils are decoupled via the decoupling system, and defining, with a processor, a decoupling matrix representative of a set of impedances of the decoupling system with an iterative procedure that optimizes elements of the decoupling matrix to minimize the objective function and reach the decoupled operating condition.

Abstract: In a magnetic resonance (MR) apparatus and an operating method therefor, a sequence with which the MR data are to be recorded is created in or provided to a control computer of the MR apparatus. A maximum RF output and a maximum gradient performance of the scanner magnetic resonance apparatus during the performance of the sequence are determined by simulating or analyzing the performance of the sequence in the control computer, and it is verified whether the maximum RF output and/or the maximum gradient performance violate predetermined limit values. Execution of the sequence to record the MR data is performed only if the verification showed that the limit values are not violated.