Abstract: Determining parameter values in image points of an examination object in an MR system by an MRF technique. Comparison signal waveforms, established using predetermined recording parameters, and each assigned to predetermined values of the parameters to be determined, are loaded. An image point time series of the examination object is acquired with an MRF recording method such that the acquired image point time series are comparable with the loaded comparison signal waveforms. A signal comparison of a section of the respective signal waveform of the acquired one image point time series is carried out with a corresponding section of loaded comparison signal waveforms to establish similarity values. The values of the parameters to be determined on the basis of the most similar comparison signal waveforms determined are determined, and then stored or output.

Abstract: Methods, computing devices, and MRI systems that reduce artifacts produced by Maxwell gradient terms in TSE imaging using non-rectilinear trajectories are disclosed. With this technology, a RF excitation pulse is generated to produce transverse magnetization that generates a NMR signal and a series of RF refocusing pulses to produce a corresponding series of NMR spin-echo signals. An original encoding gradient waveform comprising a non-rectilinear trajectory is modified by adjusting a portion of the original encoding gradient waveform or introducing a zero zeroth-moment waveform segment at end(s) of the original encoding gradient waveform. During an interval adjacent to each of the series of RF refocusing pulses a first gradient pulse is generated. At least one of the first gradient pulses is generated according to the modified gradient waveform. An image is constructed from generated digitized samples of the NMR spin-echo signals obtained.

Abstract: Methods, computing devices, and MRI systems that reduce artifacts produced by Maxwell gradient terms in TSE imaging using non-rectilinear trajectories are disclosed. With this technology, a RF excitation pulse is generated to produce transverse magnetization that generates a NMR signal and a series of RF refocusing pulses to produce a corresponding series of NMR spin-echo signals. An original encoding gradient waveform comprising a non-rectilinear trajectory is modified by adjusting a portion of the original encoding gradient waveform or introducing a zero zeroth-moment waveform segment at end(s) of the original encoding gradient waveform. During an interval adjacent to each of the series of RF refocusing pulses a first gradient pulse is generated. At least one of the first gradient pulses is generated according to the modified gradient waveform. An image is constructed from generated digitized samples of the NMR spin-echo signals obtained.

Abstract: The disclosure relates to techniques for reducing eddy current-induced magnetic field interferences for a diffusion imaging pulse sequence. A gradient impulse response function (GIRF) is determined, and an interference gradient sequence (Gx/y/z(t)) is defined on the basis of the diffusion imaging pulse sequence. A time interval (t1, t2) is determined for the acquisition of diffusion image data. On the basis of the determined gradient impulse response function (GIRF) and the interference gradient sequence (Gx/y/z(t)), a time-dependent magnetic field deviation (?Bx/y/z(t)) in the determined time interval (t1, t2) is determined. An image distortion of an acquisition of diffusion imaging is compensated, which takes place by application of the diffusion imaging pulse sequence on the basis of the determined magnetic field deviation (?Bx/y/z(t)).

Abstract: Determining parameter values in image points of an examination object in an MR system by an MRF technique. Comparison signal waveforms, established using predetermined recording parameters, and each assigned to predetermined values of the parameters to be determined, are loaded. An image point time series of the examination object is acquired with an MRF recording method such that the acquired image point time series are comparable with the loaded comparison signal waveforms. A signal comparison of a section of the respective signal waveform of the acquired one image point time series is carried out with a corresponding section of loaded comparison signal waveforms to establish similarity values. The values of the parameters to be determined on the basis of the most similar comparison signal waveforms determined are determined, and then stored or output.

Abstract: The disclosure relates to a computer implemented method for magnetic resonance imaging. The method includes: receiving at least a first and a second subset of k-space data as radio frequency signals emitted from excited hydrogen atoms of a subject; sampling the first and second subset of k-space data; choosing the first subset of k-space data as a base subset of k-space data; estimating motion parameters of the second subset of k-space data against the base subset of k-space data; and correcting the second subset of k-space data based on the estimated motion parameters of the second subset of k-space data. The motion parameters of the second subset of k-space data are parameters of a non-linear motion estimating function representing a motion of the subject between receiving the first subset of k-space data and receiving the second subset of k-space data.

Abstract: The disclosure relates to techniques for reducing eddy current-induced magnetic field interferences for a diffusion imaging pulse sequence. A gradient impulse response function (GIRF) is determined, and an interference gradient sequence (Gx/y/z(t)) is defined on the basis of the diffusion imaging pulse sequence. A time interval (t1, t2) is determined for the acquisition of diffusion image data. On the basis of the determined gradient impulse response function (GIRF) and the interference gradient sequence (Gx/y/z(t)), a time-dependent magnetic field deviation (?Bx/y/z(t)) in the determined time interval (t1, t2) is determined. An image distortion of an acquisition of diffusion imaging is compensated, which takes place by application of the diffusion imaging pulse sequence on the basis of the determined magnetic field deviation (?Bx/y/z(t)).

Abstract: In a magnetic resonance fingerprinting method and apparatus for improved determination of local parameter values of an examination object, in which at least two signal comparisons of acquired picture element time series are carried out with comparison signal curves for determination of parameter values. A further (subsequent) signal comparison takes into account results of a preceding signal comparison. This multi-stage determination of parameter values allows an increase of the spatial resolution and the precision with which the parameter values can be determined.

Abstract: The disclosure relates to a computer implemented method for magnetic resonance imaging. The method includes: receiving at least a first and a second subset of k-space data as radio frequency signals emitted from excited hydrogen atoms of a subject; sampling the first and second subset of k-space data; choosing the first subset of k-space data as a base subset of k-space data; estimating motion parameters of the second subset of k-space data against the base subset of k-space data; and correcting the second subset of k-space data based on the estimated motion parameters of the second subset of k-space data. The motion parameters of the second subset of k-space data are parameters of a non-linear motion estimating function representing a motion of the subject between receiving the first subset of k-space data and receiving the second subset of k-space data.

Abstract: Some aspects of the present disclosure relate to ultrashort-echo-time (UTE) imaging. In one embodiment, a method includes acquiring UTE imaging data associated with an area of interest of a subject. The acquiring comprises applying an imaging pulse sequence with a three-dimensional (3D) spiral acquisition and a nonselective excitation pulse. The method also includes reconstructing at least one image of the area of interest from the acquired UTE imaging data.

Abstract: In a method for determining magnetic resonance (MR) parameters, an MR fingerprint of a voxel is acquired by execution of a pulse sequence, the MR fingerprint is provided as an input into the input layer of a trained neural network, and at least one MR parameter relating to the MR fingerprint is provided at the output layer of the neural network.

Abstract: In some aspects, the disclosed technology relates to magnetic field monitoring of spiral echo train imaging. In one embodiment, a method for spiral echo train imaging of an area of interest of a subject includes measuring k-space values and field dynamics corresponding to each echo of a spiral echo pulse train, using a dynamic field camera and a magnetic resonance imaging (MRI) system. The dynamic field camera is configured to measure characteristics of fields generated by the MRI system; the characteristics include at least one imperfection associated with the MRI system. The spiral echo pulse train corresponds to a spiral trajectory scan from the MRI system that obtains magnetic resonance imaging data using a pulse sequence which applies spiral gradients in-plane with through-plane phase encoding.

Abstract: In a magnetic resonance fingerprinting method and apparatus for improved determination of local parameter values of an examination object, in which at least two signal comparisons of acquired picture element time series are carried out with comparison signal curves for determination of parameter values. A further (subsequent) signal comparison takes into account results of a preceding signal comparison. This multi-stage determination of parameter values allows an increase of the spatial resolution and the precision with which the parameter values can be determined.

Abstract: In a method and apparatus the generation of a pixel-time series of an examination object by magnetic resonance measurement data for a undersampled measurement data set are recorded along a k-space trajectory in a repetition of a pulse sequence. The pulse sequence is repeated at least once again in each case with the radiation of other RF pulses and/or with activation in each case of other gradients such that, on each repetition, after the one RF excitation pulse, measurement data are measured along a further k-space trajectory, and are stored in respective measurement data sets. The repetitions are performed such that measurement data are measured along an optimized selection of k-space trajectories in successive repetitions. From each of the measurement data sets obtained, an image data set is reconstructed, from which at least one pixel-time series is compiled for at least one pixel from the reconstructed image data sets.

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 method, computer and magnetic resonance imaging system for determining a control sequence for operating the magnetic resonance imaging system to generate magnetic resonance image data of a region to be imaged of an examination subject, from which magnetic resonance raw data are acquired, information describing the anatomical structure of the region to be imaged is made available in the computer, and a surrounding area and a central area are specified in the region to be imaged dependent on the determined anatomical structure. Furthermore, a one-dimensional water/fat saturation pulse sequence for saturating the surrounding areas is determined and a multidimensional water/fat saturation pulse sequence for saturating the central area is determined.

Abstract: In a method and apparatus for magnetic resonance (MR) fingerprinting, parameters that describe a starting k-space trajectory, along which measurement data are to be acquired in an MR fingerprinting sequence, are loaded into a computer, and at least one measurement k-space trajectory is created in the computer by fluctuating one of the parameters of the starting k-space trajectory. Measurement data are recorded along the measurement k-space trajectory, and the MR fingerprinting sequence is repeated with a different measurement trajectory in each repetition, produced by fluctuation of the at least one parameter of the starting k-space trajectory.

Abstract: In a method and apparatus for the correction of image data dynamically acquired with a magnetic resonance imaging method, a reliable B0 field map is recorded as a basic reference field map. Image data (VB) with distorted coordinates are also acquired over a predefined recording time. In addition, a set of distorted, dynamically obtained B0 field maps is acquired during the recording time. Incorrect B0 field maps are identified by comparison of the dynamically obtained B0 field maps with the basic reference field map, and the set of distorted, dynamically obtained B0 field maps is corrected accordingly. The acquired image data with distorted coordinates are corrected with the use of the corrected set of distorted, dynamically obtained B0 field maps.

Abstract: In a method for determining magnetic resonance (MR) parameters, an MR fingerprint of a voxel is acquired by execution of a pulse sequence, the MR fingerprint is provided as an input into the input layer of a trained neural network, and at least one MR parameter relating to the MR fingerprint is provided at the output layer of the neural network.

Abstract: In some aspects, the disclosed technology relates to magnetic field monitoring of spiral echo train imaging. In one embodiment, a method for spiral echo train imaging of an area of interest of a subject includes measuring k-space values and field dynamics corresponding to each echo of a spiral echo pulse train, using a dynamic field camera and a magnetic resonance imaging (MRI) system. The dynamic field camera is configured to measure characteristics of fields generated by the MRI system; the characteristics include at least one imperfection associated with the MRI system. The spiral echo pulse train corresponds to a spiral trajectory scan from the MRI system that obtains magnetic resonance imaging data using a pulse sequence which applies spiral gradients in-plane with through-plane phase encoding.