Methods, devices, systems and apparatus for magnetic resonance imaging are provided. In an example, a method includes: obtaining M imaging data sets collected by a receiving coil array including N coil channels under M radio-frequency excitations, determining odd echo phase information and even echo phase information for each of the imaging data sets, mapping M odd echo data sets and M even echo data sets of the imaging data sets as a virtual imaging data set for a virtual coil array that includes NM2 virtual coil channels, and performing parallel magnetic resonance imaging based on the odd echo phase information and the even echo phase information of each of the imaging data sets, the virtual imaging data set and parallel reconstruction reference data.

A magnetic resonance imaging (MRI) method is provided. The method includes: a first echo signal and a second echo signal generated from each of channels of a MRI device are acquired by performing a pre-scanning according to an imaging sequence; a correction displacement with which an imaging phase consistency is maximum is determined by shifting a signal curve of the second echo signal for each of the channels for a plurality of times; a one-order phase correction value and a zero-order phase correction value for the channels are determined under the imaging sequence according to the correction displacement; a formal scanning is performed according to the imaging sequence to obtain scanning data; and a phase correction is performed on the scanning data according to the one-order phase correction value and the zero-order phase correction value to obtain target scanning data for reconstructing an image.

A magnetic resonance (MR) imaging system includes a memory for storing machine executable instructions and preparation pulse sequence commands. The preparation pulse sequence commands are configured to control the system to acquire the preliminary MR data as a first data portion and a second data portion; to generate a first bipolar readout gradient during acquisition of the first portion; and to generate a second bipolar readout gradient during acquisition of the second portion, wherein the first bipolar readout gradient has an opposite polarity to the second bipolar gradient. The system is further configured to calculate a measured normalised phase correction quantity in image space using the first and second data portions; and fit a modeled phase correction to the measured phase error, wherein modeled phase correction is an exponential of a complex value multiplied by a phase error function that is spatially dependent.

Systems and methods for suppressing Nyquist ghost for diffusion weighted magnetic resonance imaging are disclosed. An exemplary method includes acquiring multiple k-space data sets using multiple sets of diffusion weighted imaging pulse sequences, reconstructing a magnetic resonance image from each of the multiple k-space data sets respectively, and averaging magnitudes of the magnetic resonance images to generate an average magnitude magnetic resonance image.

A system for performing magnetic resonance imaging (MRI) of a subject has a pulse sequence system that generates a pulse sequence and has a gradient system, a plurality of gradient coils, a radio-frequency system, and a plurality of RF coils. The pulse sequence system causes the subject to emit MR signals which are captured as k-space data. The system also has a k-space ordering processor that collects first k-space data and second k-space data, an MR signal modeler that generates a signal variation model, and a compensation module that applies the signal variation model to the second k-space data collected to produce compensated k-space data. A display processor reconstructs the compensated k-space data into an image of the subject. The compensated data accounts for variation in magnetization during the pulse sequence and k-space data collection to reduce artifacts in the images.

A Magnetic Resonance Imaging (MM) system, called ULTRA (Unlimited Trains of Radio Acquisitions), can operate with essentially no magnetic gradient reversals. Each of a multitude of small receiver coils arranged in a 3D array around the imaging volume simultaneously acquires MR signal from the entire volume. This greatly increases the rate of MR signal acquisition and allows a full MR image to be reconstructed in as little as 1 millisecond. Both electrical and audible noise is greatly reduced.

A method for magnetic resonance imaging (MRI) may include cause, based on a pulse sequence, a magnetic resonance (MR) scanner to perform a scan on an object. The pulse sequence may include a steady-state sequence and an acquisition sequence that is different from the steady-state sequence. The steady-state sequence may correspond to a steady-state phase of the scan in which no MR data is acquired. The acquisition sequence may correspond to an acquisition phase of the scan in which MR data of the object is acquired. The method may also include generating one or more images of the object based on the MR data.

The invention relates to a method of Dixon-type MR imaging. It is an object of the invention to provide a method that enables efficient and reliable water/fat separation. The method of the invention comprises the following steps: subjecting an object (10) to an imaging sequence, which comprises at least one excitation RF pulse and switched magnetic field gradients, wherein two echo signals, a first echo signal and a second echo signal, are generated at different echo times (TE1, TE2), acquiring the echo signals from the object (10), reconstructing a water image and/or a fat image from the echo signals, wherein contributions from water and fat to the echo signals are separated using a two-point Dixon technique in a first region of k-space and a single-point Dixon technique in a second region of k-space, wherein the first region is different from the second region. In other words, the invention proposes an adaptive switching between a two-point Dixon technique for water/separation, applied to both the first and second echo signals, and a single-point Dixon technique applied to one of the two echo signals, i.e. the first echo signal data or the second echo signal data, depending on the position in k-space. Moreover, the invention relates to a MR device (1) and to a computer program to be run on a MR device (1).

Automatically determining a correction factor for producing MR images includes outputting a first readout gradient along a readout dimension, reading out a first MR signal from a subject during the output of the first readout gradient, and specifying a second readout gradient having a theoretically identical gradient moment to the first readout gradient. A temporal waveform that differs from a temporal waveform of the first readout gradient is specified for the second readout gradient. The second readout gradient is output along the readout dimension. A second MR signal is read out from the subject during the output of the second readout gradient. A first extent of a representation of the subject is determined based on the first MR signal. A second extent of a representation of the subject is determined based on the second MR signal. A correction factor is obtained from a ratio between the first and second extents.

Systems and methods include conversion of a first frame of k-space data acquired using a first initial readout polarity to first hybrid (k.sub.x, y)-space data, conversion of a second frame of k-space data acquired using a second initial readout polarity to second hybrid (k.sub.x, y)-space data, determination of a relationship between phase difference and y-position based on phase differences between a plurality of pixels located at k.sub.x=a of first hybrid (k.sub.x, y)-space data and a plurality of pixels at k.sub.x=b of second hybrid (k.sub.x, y)-space data, where a and b are constants, modification of the second hybrid (k.sub.x, y)-space data based on the relationship, conversion of the modified second hybrid (k.sub.x, y)-space data to a modified second frame of k-space data, generation of two single-polarity readout k-space frames based on the first frame of k-space data and the modified second frame of k-space data, and correction of a third frame of EPI image data based on the two single-readout polarity k-space frames.