Abstract: A method comprises acquiring navigation data during navigation scans at each of a plurality of points in time. A plurality of magnetic resonance imaging (MRI) k-space data corresponding to an imaged object are acquired at the plurality of points in time using Cartesian sampling, the k-space data including at least two spatial dimensions, a time. The respective motion state for each of the k-space data are computed based on the navigation data. At least one image is reconstructed from the plurality MRI k-space data using k-space data corresponding to at least two motion states and the same point in time to reconstruct the at least one image.

Abstract: In a method to correct noise effects in magnetic resonance (MR) images, which is executed in a processor (computer), the processor executes a fitting algorithm in order to calculate initial values for each of selected variables in signal model that models noise effects in a modeled, noise-containing MR image. The processor then iteratively executes the same or a different fitting algorithm, in order to generate final values for each of the selected variables. The processor is provided with an actual, acquired MR image that contains noise, and the processor uses the final values of the selected variables to calculate synthetic signal intensities in the MR image, thereby producing a synthetic MR image with no noise bias effects of errors. This synthetic image is made available in electronic form at an output of the processor, as a data file.

Abstract: In a method and apparatus for the reconstruction of image data for at least two different chemical substance types, the reconstruction relates to a defined region of an examination object and is based on raw data acquired from the defined region at different echo times by a magnetic resonance scan. The reconstruction is implemented using a target function that includes a regularization term that correlates image data of the different echo times. A method for ascertaining image data for at least two different chemical substance types in a defined region of an examination object by an imaging magnetic resonance scan can also be implemented.

Abstract: In a method and apparatus for quantitative magnetic resonance (MR), MR signals of a subject volume are acquired using various values of at least one acquisition parameter. First and second functions are respectively specified, by which an MR signal can be determined, depending on a first parameter and the at least one acquisition parameter, and depending on a second parameter and the at least one acquisition parameter. First and second subsets of the MR signals are determined respectively for the first parameter and the second parameter. The first subset differs from the second subset. The first and second parameters are determined respectively such that MR signals calculated using the first function correspond as closely as possible to the MR signals of the first subset, and MR signals calculated using the second function correspond as closely as possible to the MR signals of the second subset.

Abstract: A method for magnetic resonance (MR) imaging is provided. A first sampling mask is provided for sampling along a first set of parallel lines extending in a first direction in k-space. A second sampling mask is provided for sampling along a second set of parallel lines extending in a second direction in k-space. The second direction is orthogonal to the first direction. A first set of MR k-space data is sampled using an MR scanner, by scanning a subject in the first direction using the first sampling mask. A second set of MR k-space data is sampled using the MR scanner, by scanning the subject in the second direction using the second sampling mask. An MR image is reconstructed from a combined set of MR k-space data including the first set of MR k-space data and the second set of MR k-space data.

Abstract: A method for reconstructing dynamic image data is described. In the method, raw data is acquired in a time-dependent manner from an examination region, wherein at least some of the raw data is assigned various values of movement parameters. First time-dependent image data based on acquired raw data is reconstructed. Furthermore, deformation fields based on the first image data are determined as a function of at least two time-dependent movement parameters. Based on the deformation fields, the raw data and the first image data, corrected image data is then generated. Furthermore, a reconstruction apparatus is described. Moreover, a magnetic resonance imaging system is described.

Abstract: In a magnetic resonance (MR) apparatus and a method for operating such an apparatus, a T1 parameter map is generated with fat fraction correction, by using a model in which the fat fraction of acquired MR data is used as a known parameter. The T1 values from the acquired MR data are fat fraction-corrected in such a manner, so as to generate fat fraction-corrected entries for the T1 parameter map according to the model.

Abstract: In a magnetic resonance method and apparatus for determination of a measurement variable that is relevant to a function of an organ of a patient, a first longitudinal relaxation rate R11 is determined before a contrast medium is administered to the patient. A second longitudinal relaxation rate R12 is determined after a contrast medium is administered to the patient. A property of the contrast medium in the organ is determined based on R11 and R12. The measurement variable is determined based on the property of the contrast medium in the organ.

Abstract: A method for magnetic resonance (MR) imaging is provided. A first sampling mask is provided for sampling along a first set of parallel lines extending in a first direction in k-space. A second sampling mask is provided for sampling along a second set of parallel lines extending in a second direction in k-space. The second direction is orthogonal to the first direction. A first set of MR k-space data is sampled using an MR scanner, by scanning a subject in the first direction using the first sampling mask. A second set of MR k-space data is sampled using the MR scanner, by scanning the subject in the second direction using the second sampling mask. An MR image is reconstructed from a combined set of MR k-space data including the first set of MR k-space data and the second set of MR k-space data.

Abstract: In a method and a magnetic resonance system to determine the T1 time of water and the T1 time of fat in a predetermined volume segment of an examination subject, magnetic field gradients are activated to generate multiple gradient echoes. First echoes are acquired at at least two different echo times based on RF pulses with a first flip angle. A first water magnetization and a first fat magnetization are determined for each voxel of the volume segment from the first echoes, according to the Dixon method. Second echoes are acquired at at least two different echo times based on RF pulses with a second flip angle. A second water magnetization and a second fat magnetization are determined for each voxel of the volume segment depending on the second echoes according to the Dixon method.

Abstract: In a magnetic resonance (MR) apparatus and method to evaluate the consistency of a signal model used to generate a quantitative parameter map, the residual of the quantitative parameter map is calculated and a residual map is generated. The residual map is displayed together with the quantitative parameter map, with the residual map serving as an indicator of the quality of fit of the signal model.

Abstract: A method for performing a magnetic resonance image reconstruction with spatially varying coil compression includes using a non-Cartesian acquisition scheme to acquire a multi-coil k-space dataset fully sampled along a fully sampled direction and decoupling the multi-coil k-space dataset along the fully sampled direction to yield a plurality of uncompressed coil data matrices. The plurality of uncompressed coil data matrices are compressed to yield a plurality of virtual coil data matrices which are aligned along the fully sampled direction to yield a plurality of aligned virtual coil data matrices. The aligned virtual coil data matrices are coupled along the fully sampled direction to yield a compressed multi-coil k-space dataset. Intensity values in the plurality of aligned virtual coil data matrices are normalized based on the plurality of uncompressed coil data matrices and an image is reconstructed using the compressed multi-coil k-space dataset.

Abstract: In a method and magnetic resonance (MR) apparatus to determine sample points of a random undersampling scheme of k-space to acquire reduced MR data with multiple coils, a set of sample points of the random undersampling scheme to acquire the reduced MR data is determined, and an indicator of a signal noise in reconstructed MR data is calculated. Furthermore, an additional sample point, which is not included in the set of sample points is determined, and a change of the indicator that results by an addition of the additional sample point to the set of sample points is calculated. The additional sample point is selectively added to the set of sample points dependent on the calculated change.

Abstract: In a magnetic resonance (MR) apparatus and a method for operating an MR apparatus, MR data are acquired and evaluated with regard to multiple tentative signal models for producing a parameter map based on one of those signal models. The parameter map shows multiple parameters that have respective effects on the MR data. Each tentative signal model is initially analyzed to determine whether any of the parameters used therein can be assumed to be at least locally constant, and the initially analyzed tentative signal model is then subjected at least to a quality of fit analysis. The tentative signal model having at least the best quality of fit analysis result is then used to generate a parameter map that is displayed at a display monitor.

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: Embodiments can provide a computer-implemented method for 3D motion correction for diffusion weighted imaging images, the method comprising acquiring a series of image slices from a medical imaging device; binning the series of image slices into bins, each bin comprising a plurality of slice locations; identifying, for each of the B-values, a dominating breathing state wherein at least one of the plurality of slice locations of the dominating breathing state contains an image slice from the series of images; identifying, for each of the B-values, one or more non-dominating breathing states; and registering, for each of the B-values, all of the one or more non-dominating breathing states to the dominating breathing state.

Abstract: Magnetic resonance (MR) data are acquired with a two-point Dixon technique in which a first spectral component and a second spectral component, for example, a water component and a fat component, are determined. A computation grid of lower resolution in comparison to the MR data is determined, wherein each grid point of the computation grid encompasses a predetermined number of adjacent image points of the MR data. A numerical optimization is implemented for each image point of the MR data, and the first spectral component and the second spectral component are calculated analytically based on the result of the numerical optimization.

Abstract: In a computer and a magnetic resonance method and apparatus for automatic characterization (classification) of liver tissue in a region of interest of a liver, at least one value tuple of the region of interest of the liver is acquired, the value tuple including at least one T1 value determined from magnetic resonance images of the region of interest, or a reciprocal value thereof, and a T2 or T2* value or a reciprocal value thereof. The value tuple is transferred into a multidimensional parameter space and the characterization of the liver tissue is then performed on the basis of the position of the value tuple in the parameter space.

Abstract: In a magnetic resonance method and apparatus for determination of a measurement variable that is relevant to a function of an organ of a patient, a first longitudinal relaxation rate R11 is determined before a contrast medium is administered to the patient. A second longitudinal relaxation rate R12 is determined after a contrast medium is administered to the patient. A property of the contrast medium in the organ is determined based on R11 and R12. The measurement variable is determined based on the property of the contrast medium in the organ.

Abstract: In a method and magnetic resonance (MR) apparatus to acquire MR data from a subject, a predetermined spectral model of a multipoint Dixon technique is used that includes at least two spectral components with respective associated relaxation rates, a first phase due to field inhomogeneities; and a second phase due to eddy current effects. MR data are acquired using a bipolar multi-echo MR measurement sequence for multiple image points wherein, for each image point, the multi-echo MR measurement sequence alternately uses positive and negative readout gradient fields for the readout of MR signals of the MR data at at least three echo times. The at least two spectral components are determined based on the MR data.