In a method for generating an MR image of an object, k-space of the MR image is separated into blades. In each blade, parallel k-space lines are provided which are separated in a phase encoding direction (PED). Each blade has a different rotation angle around a common center relative to the remaining blades. A spatial extend of the object is determined. For the blades, the extend of the object in the corresponding PED is determined. A blade specific extend of a field of view (FOV) in the PED is determined for each of the blades based on the corresponding extend of the object in the PED. The extend of the FOV in the PED differs for at least one of the blades from the extend of the remaining blades, and sampling the k-space with the blades with the determined blade specific FOV as determined for each of the blades.

According to one embodiment, a magnetic resonance imaging apparatus includes processing circuitry. The processing circuitry sets imaging parameters for each scan. The processing circuitry specifies the size of the object region in the phase encode direction from a first image. The first image acquired by using a pulse sequence different from EPI. The processing circuitry sets parameters in a field of view in the phase encode direction in a phase correction scan based on the specified size and the size of the field of view in the phase encode direction in a second scan. The phase correction scan is executed for acquiring phase correction information for the first image. The second scan is executed for acquiring a second image by using EPI.

Systems and methods for performing diffusion-weighted magnetic resonance imaging (MRI), including reconstructing and analyzing images, while preserving phase information that is traditionally discarded in such applications, are provided. For instance, background phase variations are eliminated, which enables complex-valued data analysis without the usual noise bias. As a result, the systems and methods described here provide an image reconstruction that enables true signal averaging, which increases signal-to-noise ratio (SNR) and allows higher contrast in diffusion model reconstructions without a magnitude bias.

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.

Methods, devices, systems and apparatus for determining emphysema thresholds for controlling magnetic resonance imaging are provided. In one aspect, a magnetic resonance imaging method includes: collecting magnetic resonance imaging data as first k-space data by undersampling a magnetic resonance signal, performing parallel imaging reconstruction on the first k-space data to obtain a first image, performing enhancement processing on the first image to obtain a second image that comprises distributional information of image supporting points, and performing constrained reconstruction on the first k-space data by using the second image as a prior image to obtain a third image as a magnetic resonance image to be displayed.

In an RF spoiling method and apparatus for rapid spatial saturation in magnetic resonance imaging, a first RF pulse of a spatial saturation module is applied, and a first set of RF pulses of an imaging sequence is applied after the first RF pulse. A phase of an RF pulse, closest to the first RF pulse in the time dimension, in the first set of RF pulses is not coherent with a phase of the first RF pulse. This makes a phase cycle of the spatial saturation module and a phase cycle of the imaging sequence independent of each other, so the coherence of residual signals in the transverse plane can be destroyed more effectively, thereby reducing artefacts, and improving imaging quality.

The invention relates to a method of MR imaging of an object (10) placed in an examination volume of a MR device (1). The method comprises the steps of: generating MR signals by subjecting the object (10) to a number N of shots of a multi-echo imaging sequence comprising multi-slice RF pulses (21) for simultaneously exciting two or more spatially separate image slices, with a phase offset in the slice direction being imparted to the MR signals, wherein the phase offset is varied from shot to shot, acquiring the MR signals, wherein the MR signals are received in parallel via a set of at least two RF coils (11, 12, 13) having different spatial sensitivity profiles within the examination volume, andreconstructing a MR image for each image slice from the acquired MR signals using a parallel reconstruction algorithm, wherein the MR signal contributions from the different image slices are separated on the basis of the spatial encodings of the MR signals according to the spatial sensitivity profiles of the RF coils (11, 12, 13) and on the basis of the phase offsets attributed to the respective image slices and shots. Moreover, the invention relates to a MR device for carrying out this method as well as to a computer program to be run on a MR device.

In a method and system, a reference dataset is recorded using a reference scan based on a GRE or RA RT sequence. A correction dataset is also recorded using a phase correction scan based on a non-phase-encoding EPI sequence. A measurement dataset is recorded using an SMS sequence. Slice-specific GRAPPA kernels are determined from the reference dataset and magnetic resonance images are created by a slice GRAPPA method. Data of the measurement dataset belonging to different slices is separated from one another using the slice-specific GRAPPA kernels and N/2 ghost artifacts are corrected using the correction dataset.

Various methods and systems are provided for acquiring a plurality blades of k-space data for magnetic resonance (MR) data acquisition. The plurality blades are arranged in a rotational manner around a center of the k-space. Each of the blades includes a plurality of parallel phase encoding lines indexed sequentially along a phase encoding direction of the blade. The phase encoding lines of each blade are sampled according to an asymmetric phase encoding order. The blade phase encoding orders of at least two adjacent blades are opposite to each other. This results in reducing shading and blurring artifacts in MM images.

The present disclosure relates to systems and methods for vehicle management. The systems may perform the methods to obtain a plurality of echo signals representing a subject, the plurality of echo signals being formed at a plurality of different echo times; generate a plurality of phase wrapped images based on the plurality of echo signals, each phase wrapped image comprising one or more first wrapped values; generate a phase difference map based on the plurality of phase wrapped images, the phase difference map comprising one or more second wrapped values; generate an unwrapped phase difference map by unwrapping the one or more second wrapped values in the phase difference map; determine a first field distribution map based on the unwrapped phase difference map; and generate a plurality of unwrapped phase images by unwrapping the one or more first wrapped values in each phase wrapped image based on the first field distribution map.