Abstract: 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.

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

Abstract: A method for operating a coil, through which a varying current flows, is provided. Mechanical resonance responses of the coil are recorded and are modeled by an electrical resonant circuit model. A check is made as to whether a varying current that is to be sent through the coil evokes a resonant response in the electrical resonant circuit model. The current flow through the coil is blocked if the resonant response exceeds a predefined limit value.

Abstract: In a method and magnetic resonance apparatus to reduce distortions in magnetic resonance diffusion imaging, a magnetic resonance data acquisition system is operated to acquire magnetic resonance data in a first measurement with a first diffusion weighting, and to acquire magnetic resonance data in a second measurement with a second, different diffusion weighting. A non-linear, system-specific distortion-correcting function is determined on the basis of system-specific information that is specific to said magnetic resonance data acquisition system. Correction parameters are calculated to correct distortions in subsequently-acquired diffusion-weighted magnetic resonance images, based on the data acquired in the first and second measurements with the system-specific distortion-correcting function applied thereto. The subsequently-acquired diffusion-weighted magnetic resonance images are corrected using the correction parameters to at least reduce distortions therein.

Abstract: A receiving device for magnetic resonance (MR) image signals of a body is operated in an MR system such that for at least one coil element of the receiving device, a space domain, in which a spatial sensitivity of the coil element satisfies a predetermined criterion, is determined. A center frequency and a bandwidth of the MR image signal radiated by the body in the space domain are determined for the space domain. A receive path disposed downstream of the coil element is parameterized for operation at the determined center frequency and with the determined bandwidth.

Abstract: A method for time synchronization of various components of a magnetic resonance system includes generating a series of amplitude-modulated radio-frequency pulses and associated gradient fields to deflect the magnetization of a slice detecting at least two spin signals, determining a phase difference between two of the spin signals, processing the phase difference in order to determine at least one time shift between two of the following variables that are generated by different components of the magnetic resonance system, an envelope of the amplitude-modulated radio-frequency pulses, a radio-frequency portion of the amplitude-modulated radio-frequency pulses, and one or more gradient fields, and synchronizing the associated components of the magnetic resonance system depending on the at least one time shift.

Abstract: A method for the control of a magnetic resonance system is provided. In a test phase before a magnetic resonance measurement, a test high-frequency pulse with several parallel individual high-frequency pulses is transmitted with a transmitter antenna arrangement over various different high-frequency transmitter channels. At lower transmitter power, the test high-frequency pulse generates essentially the same field distribution as an excitation high-frequency pulse to be transmitted during a subsequent magnetic resonance measurement. A high-frequency field generated by this test high-frequency pulse is measured in at least one area of a local pulse arrangement, and on the basis of the high-frequency field measured, a high-frequency field value that is to be anticipated at the local coil arrangement during the subsequent magnetic resonance measurement is determined.

Abstract: A controller of a magnetic resonance system outputs a low frequency base signal to a conversion device. While outputting the base signal to the conversion device, the controller outputs an oscillator control signal to an oscillator. The oscillator outputs a frequency signal corresponding to the oscillator control signal to the conversion device. The conversion device converts the frequency signal into a high frequency transmit pulse with the aid of the base signal and outputs the transmit pulse to a magnetic resonance transmit antenna. The magnetic resonance transmit antenna applies a high frequency field corresponding to a transmit pulse to an examination volume of the magnetic resonance system. The controller varies the oscillator control signal output to the oscillator while outputting the base signal to the modulator. The transmit pulse) has a larger bandwidth than the base signal.

Abstract: A magnetic resonance system obtaining magnetic resonance exposures of an examination subject, has an examination tunnel, a whole-body antenna with two connection terminals. The whole-body antenna cylindrically extends around the examination tunnel along a longitudinal axis. The system has a radio-frequency supply device in order to respectively supply the whole-body antenna with radio-frequency signals for emission of a radio-frequency field in the examination tunnel. The radio-frequency supply device has a radio-frequency generator for generation of a radio-frequency signal, a signal splitter that divides a radio-frequency signal coming from the radio-frequency generator into two partial signals that are phase-shifted by 90° relative to one another. Two radio-frequency feed lines are connected with the two connection terminals of the whole-body antenna. Via these radio-frequency feed lines, the two partial signals are fed into the whole-body antenna.

Abstract: A method is disclosed for at least partly determining and/or adapting an attenuation map used for attenuation correction of Positron Emission Tomography image data sets in a combined Magnetic Resonance-Positron Emission Tomography device. In at least one embodiment of the method, at least one one-dimensional magnetic resonance data set of a patient is recorded along one imaging direction; the boundaries of at least one part of the body of the patient intersected by the imaging direction are determined from the one-dimensional magnetic resonance data set; and the attenuation map is determined and/or adapted at least partly as a function of the boundaries determined.

Abstract: In a method for calibration of a magnetic resonance acquisition channel having a magnetic resonance acquisition antenna in a magnetic resonance system, in a test signal is emitted by the transmission antenna in the magnetic resonance system and is received by the acquisition antenna. Acquisition channel calibration data for the appertaining magnetic resonance acquisition channel are determined on the basis of the received test signal. The method can be implemented by a calibration data determination device for a magnetic resonance system as well as by a magnetic resonance system itself.

Abstract: In one embodiment a method for processing a reconstruction image is disclosed. The method includes recording the reconstruction image by a magnetic resonance device having a gradient coil to generate a gradient field. The method further includes distortion-correcting the reconstruction image. The method further includes back-transforming the distortion-corrected reconstruction image, by an image processing device, into a distortion-uncorrected reconstruction image, the back-transforming uses an algorithm having a first input value describing a real gradient field given at a real measuring point of the signal.

Abstract: In a method and magnetic resonance apparatus to reduce distortions in magnetic resonance diffusion imaging, a magnetic resonance data acquisition system is operated to acquire magnetic resonance data in a first measurement with a first diffusion weighting, and to acquire magnetic resonance data in a second measurement with a second, different diffusion weighting. A non-linear, system-specific distortion-correcting function is determined on the basis of system-specific information that is specific to said magnetic resonance data acquisition system. Correction parameters are calculated to correct distortions in subsequently-acquired diffusion-weighted magnetic resonance images, based on the data acquired in the first and second measurements with the system-specific distortion-correcting function applied thereto. The subsequently-acquired diffusion-weighted magnetic resonance images are corrected using the correction parameters to at least reduce distortions therein.

Abstract: In a magnetic resonance system according to a measurement protocol defined in advance and comprising multiple acquisition parameters, wherein given a non-compliance with at least one limit value (which is automatically established before the beginning of a subject-specific measurement data acquisition)—in particular a SAR limit value and/or a magneto-stimulation limit value and/or a hardware limit value—by the measurement protocol, an adaptation of at least one acquisition parameter ensues using at least one (in particular user-defined) protocol-specific rule for compliance with the limit value, and the measurement data acquisition ensues automatically according to the adapted acquisition parameters.

Abstract: In an imaging system having a number of subsystems and a control device that controls the subsystems in a coordinated manner to implement a measurement sequence and an operating method therefor, sequence control data that define different functional sub-sequences of the measurement sequence are transmitted to the control device. Different active volumes are associated with the functional sub-sequences. In addition to the sequence control data, active volume position data are provided to the control device that define bearing and extent of the active volumes associated with the different functional sub-sequences. Control signals to implement the measurement sequence for the different subsystems are generated automatically by the control device based on the sequence control data and the active volume position data so that the individual functional sub-sequences are locally optimized at least with regard to a sub-region of their associated active volume.

Abstract: In one embodiment of the present invention, a method for processing a 2D or 3D reconstruction image is disclosed which is recorded by a magnetic resonance device, including a gradient coil that generates a gradient field, and is distortion-corrected with regard to a given non-linearity—leading to an image distortion—of the gradient field using an algorithm that processes the measurement signals at different measurement points lying in the imaging volume, which algorithm, with respect to each signal processed by it, processes the first input value describing the real gradient field given at the real measurement point of the signal, in which method, for inverse transformation of the distortion-corrected reconstruction image into a distortion-uncorrected reconstruction image, use is made of the first algorithm or a second algorithm corresponding to the first algorithm, which, with respect to each signal processed by it, is given as second input value such a value which describes a fictitious gradient field at th

Abstract: In one embodiment a method for processing a reconstruction image is disclosed. The method includes recording the reconstruction image by a magnetic resonance device having a gradient coil to generate a gradient field. The method further includes distortion-correcting the reconstruction image. The method further includes back-transforming the distortion-corrected reconstruction image, by an image processing device, into a distortion-uncorrected reconstruction image, the back-transforming uses a first algorithm or a second algorithm including a second input value associated with the measurement signal, the second input value being a fictitious gradient field value associated with a distorted measuring point at which the measurement signal is processed, and the second input value is raised or lowered by a nonlinear field component of the real gradient field compared with a linear ideal gradient field.

Abstract: In an arrangement with a basic field magnet and with a gradient coil of a magnetic resonance apparatus, the basic field magnet includes superconducting coils that are arranged in a reservoir with liquid helium for cooling. The helium reservoir is surrounded by a further reservoir, designated as an outer vacuum chamber. A vacuum exists between the outer vacuum chamber and the helium reservoir. A cryoshield is arranged between the outer vacuum chamber and the helium reservoir. The gradient coil is arranged in the inner chamber of the basic field magnet. The outer vacuum chamber has an additional coating with a high electrical conductivity.

Abstract: A method is disclosed for at least partly determining and/or adapting an attenuation map used for attenuation correction of Positron Emission Tomography image data sets in a combined Magnetic Resonance-Positron Emission Tomography device. In at least one embodiment of the method, at least one one-dimensional magnetic resonance data set of a patient is recorded along one imaging direction; the boundaries of at least one part of the body of the patient intersected by the imaging direction are determined from the one-dimensional magnetic resonance data set; and the attenuation map is determined and/or adapted at least partly as a function of the boundaries determined.

Abstract: An arrangement for radiation of a radio-frequency field into an examination subject has a local coil unit with a housing. An insulating dielectric material is embodied at least at one part of the housing in order to passively compensate an inhomogeneity of the B1 field that occurs in the examination subject. An adjustment arrangement allows for fixed but detachable provision of the insulating dielectric material at the housing part.