Abstract: In a method for determining time windows in a scan sequence, in which values of setting parameters of a scan can be changed during a current scan without adversely affecting the scan data obtained with the scan, comprising the following a scan sequence is loaded into a control computer, that then determines the time windows in the scan sequence in which values of setting parameters can be changed during a current scan, on the basis of an analysis of useful coherences in the scan sequence. The determined time windows are stored or processed so as to be available to operate an imaging apparatus to execute the scan sequence.

Abstract: A method for setting an operating parameter of a medical device is provided. The method includes determining a current operating mode of the medical device. A time span available for setting the operating parameter is derived from the determined current operating mode. A setting range of the operating parameter necessary for fulfilling a pre-determined criterion is determined. A setting time necessary for setting the operating parameter according to the determined setting range is determined, and the operating parameter is set according to the setting range, provided the time span available for the setting is at least as long as the necessary setting time.

Abstract: In a method and magnetic resonance (MR) apparatus for different degrees of excitation of two different nuclear spin types with Larmor frequencies that are shifted relative to one another during recording of MR data by execution of an MR sequence, an excitation pulse sequence with at least two consecutive excitation pulses with defined time intervals for the exclusive excitation of the first spin type, and an additional pulse sequence with at least one additional pulse that acts at least on the second spin type, are used. A total pulse sequence formed by superimposition of the two pulse sequences is emitted within an excitation period of the MR sequence.

Abstract: In a method and a magnetic resonance scanner for generating a data set, a first RF pulse is applied simultaneously with a first gradient having a first amplitude and a first polarity, and at least one second gradient is applied having a second amplitude and a second polarity. A second RF pulse is applied simultaneously with a third gradient having a third amplitude and a third polarity. The third amplitude is different from the first amplitude and/or the third polarity is different from the first polarity. The scan signal generated using the second RF pulse is then read out.

Abstract: In a method and magnetic resonance (MR) apparatus for acquiring MR data from a volume of an object in which first and second excitable spin types are present that differ in their Larmor frequencies by a chemical shift, an MR sequence with at least one radio-frequency pulse sequence selectively excites the first spin type or selectively suppresses MR signals of the second spin type. A B0 map describing the basic field distribution in a region of interest of the volume is established. First and second items of distribution information, which respectively describe the spectral distribution of Larmor frequencies of the first and second spin types, are derived from the B0 map. A pulse sequence parameter that describes the excitation spectrum of the radio-frequency pulse sequence is optimized based on the items of distribution information, with regard to a quality criterion that optimizes selective excitation and/or suppression.

Abstract: In a method and magnetic resonance (MR) apparatus for reconstruction of image data of an examination object from undersampled raw MR data and reference data, undersampled raw data are used that were recorded from an examination region of the examination object by an MR control sequence, to which a reconstruction algorithm for the reconstruction of image data is assigned. A disturbance variable in the examination region is determined. A modulation function is established, which describes the influence of the disturbance variable on the MR control sequence. Modulated reference data are created on the basis of the modulation function and the reference data such that the modulated reference data are subjected to the influence of the disturbance variable on the raw data recorded by the MR control sequence. A combination algorithm is executed in order to reconstruct image data from the undersampled raw data with the use of the modulated reference data.

Abstract: In a method and computer and magnetic resonance (MR) apparatus for classifying MR measurement data acquired from an object under examination by execution of an MR fingerprinting method, wherein the MR measurement data include multiple MR signal profiles acquired by the MR fingerprinting method. At least one texture parameter is derived from the MR measurement data. The MR measurement data are classified into at least one tissue class using the at least one texture parameter. The classified MR measurement data are provided as an output.

Abstract: In a magnetic resonance measurement sequence, an inversion pulse is applied that acts on a longitudinal magnetization of a first spin species and a second spin species, for example on a water portion and a fat portion. An excitation pulse is applied after a predetermined time period. At least one manipulation pulse is subsequently applied, respectively with associated gradient pulse.

Abstract: A method and device for establishing a protocol relating to a measurement sequence for controlling a magnetic resonance tomography system, the measurement sequence is segmented into various groups of partial modules that are similar to one another. A partial module that potentially generates the greatest physiological exposure for a patient is identified. Furthermore, a test is carried out by means of a model function to determine whether physiological limiting values are being observed in the measurement sequence for the partial module. If the physiological limiting values are not being observed, parameters influencing the measurement sequence are modified and the preceding test step is repeated.

Abstract: In a magnetic resonance apparatus and a method and controller for operating such an apparatus, first and second diffusion-weighted image data are reconstructed from first and second diffusion-encoded raw data that were respectively acquired using different diffusion-encoding gradient pulse sub-sequences. The different sub-sequences differ by respectively having a different parameter that characterizes the respective sub-sequence as a function of time. The first and second reconstructed image data are compared and a deviation of the image data from normal Gaussian diffusion behavior is determined model-free on the basis of the comparison result.

Abstract: In a method and apparatus for magnetic resonance (MR) imaging, a result image is provided based on multiple MR contrasts. The result image is indicative of a value of a magnetic parameter. MR data are acquired for the multiple contrasts at different time points, in each case following preparation of a magnetization. During the acquisition of the MR data, k-space is undersampled according to a respective undersampling scheme. The undersampling schemes of the different MR contrasts are different from one another.

Abstract: In a method and apparatus for recording MR signals with an image-recording sequence with which preparation gradients for preparing the MR signals are switched before the signal readout and readout gradients, in order to predominantly record the MR signal components with a desired signal coherence pathway in the readout segment, the signal components with an undesired signal coherence pathway are suppressed by dephasing gradients. The dephasing gradients are determined independently of the time intervals in which the preparation gradients are switched, and only in dependence on the effective size of the gradient moments of the preparation gradients.

Abstract: A motion detection system detects object motion in a medical imaging system. The computer-implemented calibration method includes an automatic calibration process for determining a motion threshold for the object motion detection system, while the object is positioned for imaging by the medical imaging system. The calibration process includes: repeatedly acquiring motion detection data and repeatedly acquiring motion quantification data with a motion quantification system. The motion quantification data are analyzed to determine whether the object was mobile or immobile. If the object was immobile, an object motion threshold for the motion detection system is determined by statistical analysis of the motion detection data.

Abstract: In a method and apparatus to correct a signal phase in the acquisition of magnetic resonance signals of an object to be examined in a slice multiplexing method, magnetic resonance signals from at least two different slices of the object are detected simultaneously. In at least one slice-selection time period, a slice-selection gradient is generated by a slice-selection-gradient pulse. During the activation of the slice-selection gradient in each case a radio-frequency pulse with a slice-specific frequency is emitted for each of the slices. The radio-frequency pulses for the different slices at least partially temporally overlap and are temporally offset for the phase correction, so the duration of the slice-selection time period is shortened by modification of the slice-selection gradients.

Abstract: In a method and apparatus for magnetic resonance (MR) fingerprinting, an MR signal is acquired from a subject by radiating radio-frequency (RF) energy that produces an RF transmission field that has a localized amplitude in the subject. The RF energy is radiated with an RF pulse configuration that maps the localized RF field amplitude in the phase of the MR signal from the subject. The detected MR signal is compared to a source of stored MR signal physical or theoretical models that respectively map different localized RF transmission field information in the respective phase thereof, the stored models being respectively for different substances. A substance in the subject from which the detected MR signal curve originated is identified by comparing the detected MR signal curve to the stored models to identify a best match.

Abstract: In a method and a magnetic resonance apparatus for diffusion-weighted imaging, diffusion gradients for acquiring diffusion-weighted image data, with anisotropic diffusion directions, are determined by defining a space of achievable diffusion gradient vectors as a cuboid, and then defining a spherical shell around the gradient axes in order to determine specific values of the gradient amplitudes. The resulting diffusion gradient vectors have a direct influence on the achievable signal-to-noise ratio of an individual scan, and the method and apparatus enable an advance selection of a desired effective gradient amplitude, and the presentation to a user of candidate diffusion gradient vectors that satisfy the desired requirements.

Abstract: In a method and apparatus for recording a magnetic resonance dataset of a volume of interest of an object, at least one gradient moment is calculated as a function of at least one jump in susceptibility that is present in the volume of interest, between two sections of the volume of interest. An excitation pulse is radiated and at least one compensation moment is activated in a part volume of the volume of interest, for the at least partial compensation of a gradient moment caused by the jump in susceptibility. The signal generated by the excitation pulse is read out.

Abstract: In a magnetic resonance tomography scanner and an operating method therefor, a scanning volume is subdivided in a slice direction into multiple scanning slices, and the scan data of each of the scanning slices are acquired by a scan sequence allocated to the respective scanning slice. Each scan sequence has at least one preparation pulse allocated to the scanning slice, which causes nuclear spin excitation throughout the whole scanning volume. At least two scan sequences are implemented that differ with regard to a coil current fed during the preparation pulse to a field correction coil of the scanner for reducing a local inhomogeneity of a basic magnetic field, or that differ with regard to at least one pulse parameter of the preparation pulse. The respective coil current and/or pulse parameter is determined depending on the position of the scanning slice allocated to the respective scan sequence in the scanning volume.

Abstract: In a magnetic resonance apparatus and a method and controller for operating such an apparatus, first and second diffusion-weighted image data are reconstructed from first and second diffusion-encoded raw data that were respectively acquired using different diffusion-encoding gradient pulse sub-sequences. The different sub-sequences differ by respectively having a different parameter that characterizes the respective sub-sequence as a function of time. The first and second reconstructed image data are compared and a deviation of the image data from normal Gaussian diffusion behavior is determined model-free on the basis of the comparison result.

Abstract: In a method and magnetic resonance (MR) apparatus for reconstruction of image data of an examination object from undersampled raw MR data and reference data, undersampled raw data are used that were recorded from an examination region of the examination object by an MR control sequence, to which a reconstruction algorithm for the reconstruction of image data is assigned. A disturbance variable in the examination region is determined. A modulation function is established, which describes the influence of the disturbance variable on the MR control sequence. Modulated reference data are created on the basis of the modulation function and the reference data such that the modulated reference data are subjected to the influence of the disturbance variable on the raw data recorded by the MR control sequence. A combination algorithm is executed in order to reconstruct image data from the undersampled raw data with the use of the modulated reference data.