Siemens Aktiengesellschaft

Siemens Healthcare Gmbh

Christian Wünsch

Markus Vester

Jürgen Nistler

Thorsten Speckner

Klaus Huber

Claus Seisenberger

Georg Martschenko

Stephan Biber

Nikolaus Demharter

Johannes Reinschke

Volker Matschl

David Andrew Porter

Volker Schnetter

Uvo Hölscher

Rainer Kurth

Stephan Stöcker

Pascal Mühlich

Chih-Chung Chen

Olaf Behrendt

A system and method are provided for operating a magnetic resonance tomograph. A transmitter of the magnetic resonance tomograph transmits a predetermined test pulse with a reduced power. The magnetic resonance tomograph receives the test pulse with the local coil. A controller compares the received test pulse with a predetermined pulse response and emits a warning signal when the received test signal differs from the predetermined pulse response.

Method and device for monitoring local coils

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.

Apparatus and method for B1 limiting

A radio-frequency control system for a magnetic resonance tomography system and a method for the operation thereof are provided. The radio-frequency control system includes a controller and a radio-frequency power amplifier with amplification between a signal input and a signal output of the radio-frequency power amplifier that is dependent on a predetermined frequency response. The controller determines a control pulse for multislice excitation and outputs the pulse to the signal input of the radio-frequency power amplifier. The controller determines a high-frequency power value for the control pulse in dependence on the predetermined frequency response of the radio-frequency power amplifier.

Device and method for generating excitation pulses

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.

Apparatus and method for detecting antenna coils

A method for emitting a sequence of high frequency pulses that may have different envelopes in a magnetic resonance tomography system is provided. A digital instruction signal that specifies the envelope for the high frequency pulses that are to be emitted is received. A digital control signal is transmitted to a high frequency unit for generating high frequency pulses, depending on the instruction signal. A test signal that allows notification of a current overload situation is received. The current control signal is reduced if the test signal indicates an overload situation.

Emission of high frequency pulses in a magnetic resonance tomography system

A B1 magnetic field may be regulated during a magnetic resonance tomography (MRT) imaging sequence.

B1 field-based regulation within a sequence for NMR

A two-channel magnetic resonance tomography system is provided with a regulation circuit for an amplification system in order to be able to take into account different load situations of the MRI system in a flexible and efficient manner. It is thus possible to improve the MRI measurements greatly if the MRI system is set to the respective load situation beforehand by an idle state measurement. The adaptation may optionally also be carried out during the MRI measurement. Therefore, a multiplicity of completely different load situations may be taken into account in an optimized manner by the regulation circuit.

Two-channel magnetic resonance imaging

A method for monitoring a high-frequency transmit device of a magnetic resonance tomography system with a transmit antenna system having a plurality of transmit channels is provided. A reference transmit signal is output on different transmit channels of the transmit antenna system, respectively, at different time points, and a reference measurement signal induced by the reference transmit signal is measured on at least one of the other transmit channels using a measuring device assigned to the transmit channel. Based on the reference measurement signal, a phase deviation indicator value is determined. The phase deviation indicator value indicates a relative phase deviation between the measuring devices of the transmit channels in question.

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Röthenbach a.d. Pegnitz, Germany

Christian Wünsch