Abstract: Nuclear spins are excited in a region of interest in an object under examination by a radio-frequency pulse. During at least one phase of the radio-frequency pulse, excitation fields are transmitted while magnetic field gradients are simultaneously applied so that the magnetization of the nuclear spins moves on a trajectory through a transmission k-space. In a first phase of the at least one phase of the radio-frequency pulse, the trajectory moves at a radial distance around the center of the transmission k-space. The radial distance corresponds to the radius of a sphere superimposed with at least one radial harmonic.

Abstract: Monitoring a specific absorption rate of a subject during a magnetic resonance tomography examination with a magnetic resonance tomography system with a multi-element coil with several transmission channels, comprising the following steps: monitoring the transmission channels with an initial monitoring system to obtain initial monitoring signals; monitoring a subset of the transmission channels with a second monitoring system to obtain second monitoring signals; comparing the second monitoring signals with the first monitoring signals of the transmission channels which belong to the subset monitored by the second monitoring system; repeating the previous steps, wherein a different subset is monitored in each case until second monitoring signals for all subsets of the transmission channels have been received by the second monitoring system and compared with the corresponding first monitoring signals; determining whether the first monitoring signals and the second monitoring signals match, and whether an upper

Abstract: A method is provided for ascertaining an item of local specific absorption rate (SAR) information in an object under effect of specified radio frequency pulses of a candidate group output with a radio frequency coil arrangement of a magnetic resonance facility, wherein the radio frequency pulses are embodied for manipulating nuclear spins of at least two different nuclides. The method includes implementing a parallel transmission technique for at least one nuclide; generating actuation variables assigned in accordance with the candidate group due to the actuation of the radio frequency coil arrangement; and ascertaining the item of local SAR information by an ascertainment algorithm using the actuation variables as the input data. The ascertainment algorithm is parameterized by taking into account the nuclides and respectively assigned logical coil channels thereof such that the item of local SAR information is jointly ascertained for all nuclides with the same local location reference.

Abstract: Nuclear spins are excited in a region of interest in an object under examination by a radio-frequency pulse. During at least one phase of the radio-frequency pulse, excitation fields are transmitted while magnetic field gradients are simultaneously applied so that the magnetization of the nuclear spins moves on a trajectory through a transmission k-space. In a first phase of the at least one phase of the radio-frequency pulse, the trajectory moves at a radial distance around the center of the transmission k-space. The radial distance corresponds to the radius of a sphere superimposed with at least one radial harmonic.

Abstract: A pulse-design unit for creating pulse data for controlling a magnetic resonance system includes a data interface configured for receiving an examination scheme, and a calculation module configured for generating pulse data based on an examination scheme. The pulse-design unit includes a data grid and/or parameter values created from map pairs of a plurality of patients and is configured to select and/or calculate pulse data using the data grid and/or parameter values and a provided examination scheme. A method and a control device for controlling a magnetic resonance imaging (MRI) system and a related magnetic resonance imaging system are also provided.

Abstract: A method is provided for calibration of a magnetic resonance device with a transmitting device for generating an excitation field. In a first acquisition phase, a first transmitting coil element is detuned, at least one second transmitting coil element is tuned, and an MR data set is acquired using the transmitting device. In a second acquisition phase, the first transmitting coil element, the at least one second transmitting coil element are tuned, and at least one further MR data set is acquired using the transmitting device. By an arithmetic unit, a calibration factor is determined based on the MR data set and the at least one further MR data set for calculating a total voltage value at a feeding point of the first transmitting coil element from voltage values, which may be measured at a measuring point of an electrical supply line of the first transmitting coil element.

Abstract: A computer-implemented method is disclosed for providing an actuation sequence which specifies transmit signals for at least one high-frequency transmit channel of an antenna arrangement of a magnetic resonance device for acquiring measurement data of an object under investigation by the magnetic resonance device. The method includes providing different actuation sequences, wherein each sequence is the result of an optimization method and which differs with regard to the value of an optimization parameter taken into account in the course of the optimization method. The method further includes providing a plurality of field distribution maps, (e.g., at least one B0 map and/or at least one B1 map), acquired by the or a further magnetic resonance device from the object under investigation. The method further includes selecting the actuation sequence to be used from the different actuation sequences depending on the field distribution maps and providing the actuation sequence to be used.

Abstract: A method is provided for calibration of a magnetic resonance device with a transmitting device for generating an excitation field. In a first acquisition phase, a first transmitting coil element is detuned, at least one second transmitting coil element is tuned, and an MR data set is acquired using the transmitting device. In a second acquisition phase, the first transmitting coil element, the at least one second transmitting coil element are tuned, and at least one further MR data set is acquired using the transmitting device. By an arithmetic unit, a calibration factor is determined based on the MR data set and the at least one further MR data set for calculating a total voltage value at a feeding point of the first transmitting coil element from voltage values, which may be measured at a measuring point of an electrical supply line of the first transmitting coil element.

Abstract: A pulse-design unit for creating pulse data for controlling a magnetic resonance system includes a data interface configured for receiving an examination scheme, and a calculation module configured for generating pulse data based on an examination scheme. The pulse-design unit includes a data grid and/or parameter values created from map pairs of a plurality of patients and is configured to select and/or calculate pulse data using the data grid and/or parameter values and a provided examination scheme. A method and a control device for controlling a magnetic resonance imaging (MRI) system and a related magnetic resonance imaging system are also provided.

Abstract: A computer-implemented method is disclosed for providing an actuation sequence which specifies transmit signals for at least one high-frequency transmit channel of an antenna arrangement of a magnetic resonance device for acquiring measurement data of an object under investigation by the magnetic resonance device. The method includes providing different actuation sequences, wherein each sequence is the result of an optimization method and which differs with regard to the value of an optimization parameter taken into account in the course of the optimization method. The method further includes providing a plurality of field distribution maps, (e.g., at least one B0 map and/or at least one B1 map), acquired by the or a further magnetic resonance device from the object under investigation. The method further includes selecting the actuation sequence to be used from the different actuation sequences depending on the field distribution maps and providing the actuation sequence to be used.

Abstract: In order to reduce the memory footprint used for monitoring specific absorption rate (SAR) in a magnetic resonance imaging (MRI) system, a hybrid sliding window method is provided. The method includes receiving a measured value once every first time interval, processing the measured value, and storing a value resulting from the processing in a first memory element. Measured values stored in second memory elements are summed every second time interval, where the first time interval is less than the second time interval. A representation of SAR is calculated every first time interval based on the value resulting from the processing and the sum of the measured values of the second memory elements. When the second time interval is reached, the value stored in the first memory element is moved to one of the second memory elements, and the value stored in the first memory element is reset to zero.

Abstract: A method for controlling a magnetic resonance system outputs a pulse sequence including a first slice-selective excitation pulse that excites a first slice with a first magnetization. The pulse sequence includes a second slice-selective excitation pulse that excites a second slice with the first magnetization and a third slice-selective excitation pulse that excites the first slice with a second magnetization that cancels the first magnetization. The pulse sequence also includes and a fourth slice-selective excitation pulse that excites the second slice with a magnetization that cancels the first magnetization. The first slice and the second slice intersect.

Abstract: A method for operating a transmission device of a magnetic resonance device is provided. In order to actuate coil elements of a radiofrequency coil with different phases, phase differences in a reference plane are taken into consideration. In a first calibration measurement to be performed once for each transmission path, a first phase of a transmitted radiofrequency signal is measured by an internal measuring device installed permanently in the transmission device spaced apart from the reference plane. A second phase of the transmitted radiofrequency signal is measured by a second, external measuring device to be connected to the reference plane for the first calibration measurement. At least one phase of the first phase and the second phase is taken into consideration in the phase-accurate actuating of the coil elements and/or for correcting further measurements with the internal measuring device.

Abstract: A circuit arrangement for driving a transmission coil arrangement with at least two individual transmission coils of a magnetic resonance system for supplying a radiofrequency signal for producing alternating electromagnetic fields over at least two channels, with in each case a digital section and an analog section, is provided. In the digital section, in an envelope generator, base frequency signals that respectively generate an envelope are provided. The circuit arrangement also includes an intermediate frequency oscillator that generates a common intermediate frequency, a frequency mixer per channel for mixing the common intermediate frequency into the base frequency signals, and in the analog sections of the channels, respectively, second frequency mixers that mix a common radiofrequency signal into each base frequency signal.

Abstract: In a method to determine a B1 phase map for at least two excitation modes of a radio-frequency coil arrangement of a magnetic resonance apparatus, the radio-frequency coil arrangement having multiple independently controllable transmission channels, and the B1 phase map describing, with spatial resolution, the phase of radio-frequency field this is generated in a respective excitation mode relative to a common reference phase map, first magnetic resonance data describing the phase change of a basic magnetic field of the magnetic resonance apparatus between a first echo time and a second echo time are acquired, and are evaluated to determine a spatially resolved Larmor frequency value that describes the deviation from a nominal Larmor frequency of the magnetic resonance apparatus.

Abstract: An MR image is produced from data acquired by radiating an RF pulse and switching multiple bipolar magnetic field gradients to generate multiple gradient echoes that are acquired in a raw data set with multiple raw data lines by a reception coil, the multiple gradient echoes being acquired with bipolar magnetic field gradients of different polarity. Due to the bipolar magnetic field gradients of different polarity, in the raw data set first raw data lines are filled with MR signals in one direction in raw data space, and second raw data lines are filled with MR signals in the opposite direction.

Abstract: Methods are provided for measurement of RF excitation pulses by a magnetic resonance device. The methods include the following acts: (1) sending of an RF excitation pulse by a radio-frequency system of the magnetic resonance device, (2) triggering of a receive event for capturing the RF excitation pulse by the control device of the magnetic resonance device, and (3) capturing of the sent RF excitation pulse in the form of excitation data by the radio frequency system. The excitation data may be used for checking process execution sequences.

Abstract: In a method for correction of a B0 field map measured with a magnetic resonance device, that describes deviations from a nominal field strength in the homogeneity area of the magnetic resonance device by deviations from a nominal frequency for protons bonded to water, the deviations being represented as Larmor frequency values for different picture elements shifted by chemical shifts, the B0 field map is recorded with spins of the fat and water protons not in phase. The B0 field map is segmented by evaluating the differences of the Larmor frequency values of adjacent picture elements of the B0 field map in at least two contiguous clusters. For each cluster, a decision is made on the basis of a smoothness criterion and a compactness criterion as to whether a cluster containing a majority of protons bonded into fat is involved.

Abstract: A method and control device operate a magnetic resonance system in order to execute a first pulse sequence that includes an excitation phase and an acquisition phase. In the excitation phase, a first gradient is applied in a gradient direction to generate a spatially dependent basic magnetic field. A selective radio-frequency excitation pulse is executed, wherein the selective radio-frequency excitation pulse excites a first material and does not excite a second material in a first partial region of an examination volume, and wherein the selective radio-frequency excitation pulse does not excite the first material and excites the second material in a second partial region of the examination volume. In the acquisition phase, non-selective refocusing pulses are executed in order to acquire raw data of the first and second partial region of the examination volume, which acquisition is spatially coded along the gradient direction.

Abstract: A method for generation of a radio-frequency (RF) pulse for excitation of nuclear spins in a predetermined layer of a specimen for magnetic resonance imaging and a magnetic resonance imaging device for performing the method are provided. The method includes determining a variation of a magnetic field in a measuring volume, and defining a spectral frequency distribution of the RF pulse. The RF pulse with the spectral frequency distribution is configured to excite nuclear spins in the specimen. The nuclear spins are polarized by the magnetic field at a predetermined flip angle in the measuring volume under a boundary condition of a substantially minimum energy content. The method also includes generating the RF pulse with the defined spectral frequency distribution.