In a method for creating a composite magnetic resonance (MR) raw dataset for an MR apparatus, a first MR raw dataset is determined from a first partial section of an examination object, in which a first region of the first MR raw dataset is not filled with MR signals and in which a second region of the first MR raw dataset is filled with MR signals. An MR overview dataset is determined, which has been acquired with a number of reception coils of the MR apparatus and for which an overall field of view of the number of MR coils is larger than a reception region of the number of MR receive coils. A partial dataset is determined from the MR overview dataset, which has MR signals that originate from the first partial section of the examination object from which the first MR raw dataset originates. MR partial raw data are reconstructed for the first region of the MR raw dataset, using the partial dataset determined. The composite MR raw dataset is created from the second partial region of the first MR raw dataset and the MR partial raw data.

In a magnetic resonance (MR) method and apparatus, first and second MR data are acquired from respective echo trains with gradient moments of one echo train being in a sequence that is an inversion of at least a portion of the sequence of gradient moments in the second echo train. The MR signals are acquired from at least two substances in a volume of a subject, so that the relaxation of the respective nuclear spins influences the manner by which the first and second data are entered into k-space, so that when an image is reconstructed, the filter effect induced by such relaxation is compensated for.

In a method and magnetic resonance (MR) apparatus for reducing artifacts in an image dataset reconstructed from MR raw data that were acquired by radial sampling using different coil elements, for each of at least some of the coil elements, exclusion information is determined that identify MR data from that coil element that are responsible for at least one artifact, by a comparison of a sensitivity map, which defines a spatial reception capability of that coil element, with at least one comparison dataset obtained from at least a portion of the MR data from that coil element. At least the MR data identified from the exclusion information are excluded from the reconstruction of the image dataset.

Magnetic resonance (MR) data are acquired by applying magnetic fields to an examination region concurrent with stimulated echo signals, such that trajectories, which are not straight lines, are generated in k-space. For this purpose, sequence of RF pulses is applied to generate the stimulated echo signals in the examination object, undersampled MR measurement data are detected during reception of the stimulated echo signals in the at least two receiving coils, along the curved k-space trajectories, and fully sampled MR measurement are generated from the undersampled MR measurement data using sensitivity information of the at least two receiving coils. Alternatively, the MR measurement data are fully sampled in a central region of k-space, and a region outside the central region is not fully sampled, and a phase correction with a Partial Fourier technique is executed on the MR measurement data using fully sampled MR measurement data from the central region of k-space.

A magnetic resonance imaging (MRI) apparatus for obtaining a magnetic resonance (MR) image, based on a multi-echo sequence, and a method of the MRI apparatus are provided. The MRI apparatus includes a data obtainer configured to obtain first echo data, based on an echo that is generated at a first echo time, and obtain second echo data, based on an echo that is generated at a second echo time later than the first echo time, the first echo data including a part overlapping a part included in the second echo data in a k-space. The MRI apparatus further includes an image processor configured to reconstruct the MR image, based on the first echo data and the second echo data.

A method of magnetic resonance imaging includes executing an imaging sequence, in response to the imaging sequence, acquiring magnetic resonance data, entering the acquired magnetic resonance data in k-space in a memory along a predetermined k-space trajectory, and modifying the k-space trajectory during acquisition of the magnetic resonance data.

In calculating a local magnetic field distribution caused by a magnetic susceptibility difference between living tissues, using MRI, a local frequency distribution with a high SNR is calculated in a short computation time. Multi-echo complex images obtained by measurement of at least two different echo times using the MRI are converted into low-resolution images. A global frequency distribution caused by global magnetic field changes and an offset phase distribution including a reception phase and a transmission phase are separated from a phase distribution of the low-resolution multi-echo complex images. Thus calculated global frequency distribution and the offset phase distribution are enhanced in resolution. A local frequency distribution of each echo is calculated from the measured multi-echo complex images, the high-resolution global frequency distribution, and the high-resolution offset phase distribution. The local frequency distributions of respective echoes are subjected to weighted averaging, whereby a final local frequency distribution is calculated.

A method of image processing of magnetic resonance (MR) images for creating de-noised MR images, comprises the steps of providing image data sets including multiple complex MR images (S7), subjecting the MR images to a wavelet decomposition (S12) for creating coefficient data sets of wavelet coefficients (S.sub.n,m) representing the MR images in a wavelet frequency domain, calculating normalized coefficient data sets of wavelet coefficients Formula (I) (S17), wherein the coefficient data sets are normalized with a quantitative amount of variation, in particular standard deviation Formula (II), of noise contributions included in the coefficient data sets (S.sub.n,m), averaging the wavelet coefficients of each coefficient data set (S18) for providing averaged wavelet coefficients Formula (III) of the coefficient data sets, calculating phase difference maps (.sub.n,m) for all coefficient data sets (S20), wherein the phase difference maps provide phase differences between the phase of each wavelet coefficient and the phase of the averaged wavelet coefficients Formula (III), calculating scaled averaged coefficient data sets of wavelet coefficients by scaling the averaged wavelet coefficients Formula (III) with scaling factors (C.sub.n,m), which are obtained by comparing parts of the normalized wavelet coefficients of the normalized coefficient data sets Formula (I) that are in phase with the averaged wavelet coefficients Formula (III) (S22), calculating rescaled coefficient data sets of wavelet coefficients Formula (IV) (S24) by applying a transfer function Formula (V) on the coefficient data sets (S.sub.n,m) and on the scaled averaged coefficient data sets, wherein the transfer function includes combined amplitude and phase filters, each depending on the normalized coefficient data sets Formula (I) and me phase difference maps (.sub.n,m), resp., and subjecting the rescaled coefficient data sets to a wavelet reconstruction Formula (IV) (S25) for providing the denoised MR images.

In an EPI acquisition sequence for magnetic resonance signals k-space is scanned along sets of lines in k-space along opposite propagation directions, e.g. odd and even lines in k-space. Phase errors that occur due to the opposite propagation directions are corrected for in a SENSE-type parallel imaging reconstruction. The phase error distribution in image space may be initially estimated, calculated form the phase difference between images reconstructed from magnetic resonance signals acquired from the respective sets of k-space lines, or from an earlier dynamic.

In a method and magnetic resonance (MR) apparatus for data acquisition with fat-water separation in a resulting MR image, an MR data acquisition sequence is operated to acquire MR signals from a subject. Said MR signals comprise fat signals originating from fat in the subject and water signals originating from water in the subject, are acquired by executing a frequency-modulated balanced steady-state free-precession (bSSFP) sequence. The MR signals are entered as numerical values into a memory organized as k-space, the memory thereby containing k-space data. An image is reconstructed from the k-data and subjected to regional phase correction. The corrected image being composed of respective pixels having an intensity produced by the fat signals and an intensity produced by the water signals, with the respective pixels being readily distinguishable from each other in the image due to use of the frequency-modulated bSSFP sequence and the block regional correction.