The disclosure provides a modified EPI sequence for acquiring multi-shot and multi-echo images with interleaved blip-up and blip-down phase encoding; the blip-up and blip-down images are processed by topup in FSL to estimate the inhomogeneous main magnetic field B.sub.0 map that causes image distortions; the B.sub.0 map is then incorporated into the encoding matrix with a low rank constraint to form a joint reconstruction model; the joint reconstruction model is solved to obtain multiple distortion-free images; and the multiple distortion-free images are matched to dictionary to simultaneous acquire the quantitative T.sub.2 (=1/R.sub.2) and T.sub.2* (=1/R.sub.2*) maps. In the phantom and in-vivo measurements, the disclosed method rapidly acquires the comparable quantitative images within one hold-breath (for 20 s) to the conventional mapping method, thus providing important practical application value for evaluation of liver damage, iron level and cancer lesion.

In a MR water-fat image separation method and device, within one echo period, a first echo set under a first readout gradient polarity and a second echo set under a second readout gradient polarity are acquired. The first and second readout gradient polarities may be opposite, and echoes in the first echo set may be positionally one-to-one symmetric to echoes in the second echo set with respect to the echo center of the echo period. A first echo image set is obtained based on first echo set data acquired in each echo period, and a second echo image set is obtained based on second echo set data acquired in each echo period. Using the first and second echo image sets, a Dixon water-fat separation calculation is performed to obtain a water image and a fat image. The method and device can advantageously increase acquisition efficiency and the signal-to-noise ratio.

Techniques are disclosed for use in magnetic resonance imaging (MRI) for exciting spins of a first material and spins of a second material. A first spin echo signal is acquired when the excited spins include a first phase difference, which is given by Δ, and a second spin echo signal is acquired when the excited spins of the first material and the excited spins of the second material include a second phase difference, which is given by −Δ. An absolute value of Δ lies within the interval ]0,π[. A first image for the first material and/or a second image for the second material is generated by a computing unit depending on the first spin echo signal and the second spin echo signal.

An apparatus for non-invasive evaluations and in-vivo diagnostics includes an open magnet, an RF antenna, and an NMR analytics logical circuit communicatively coupled to the RF antenna, wherein the open magnet is shaped to generate a static magnetic field that extends unilaterally into an object or internal organ of a subject when the open magnet is positioned against or in proximity to the object or subject, the static and RF magnetic fields shaped to generate a sensitive volume within a target region. The RF antenna or antenna array is configured to transmit RF pulses into the target region of the object or internal organ and receive sets of NMR signals generated by hydrogen or other elements, and the NMR analytics logical circuit is configured to obtain and analyze sets of NMR signals.

A method and apparatus for generating a T1 or T2 map for a three-dimensional (3D) image volume of a subject. The method includes acquiring first, second, and third 3D images of the image volume of the subject. Signal evolutions of voxels through the first to third 3D images by comparing voxel intensity levels of corresponding voxel locations in the first, second, and third 3D images. A simulation dictionary representing the signal evolutions for a number of different tissue parameter combinations is obtained. The T1 or T2 map is generated by comparing the determined signal evolutions to entries in the dictionary and by finding, for each of the determined signal evolutions, the entry in the dictionary that best matches the determined signal evolution.

The present disclosure relates to a method for correcting chemical shift artifacts, CSA, which arise in the magnetic resonance DIXON method when using bipolar readout gradients (fast DIXON MR) to capture the in-phase and opposed-phase echoes.

The invention relates to a method of Dixon-type MR imaging of an object (10) placed in an examination volume of a MR device (1). It is an object of the invention to provide a method that enables an improved Dixon water/fat separation in combination with a dual-acquisition gradient-echo imaging sequence. The method comprises the steps of: subjecting the object (10) to a dual-acquisition gradient-echo imaging sequence comprising a series of temporally equidistant RF excitations, wherein one gradient echo is generated in each repetition time between successive RF excitations with the echo time alternating between a first and a second value (TE1, TE2), and wherein phase-encoding magnetic field gradients (P, S) are switched in each repetition time to sample a pre-defined region of k-space; acquiring echo signals from the object (10), wherein each gradient echo associated with either the first or the second echo time value (TE1, TE2) is sampled as a partial echo, and—reconstructing an MR image from the acquired echo signals, whereby signal contributions from water and fat are separated. Moreover the invention relates to an MR device (1) and to a computer program to be run on an MR device (1).

A method for non-invasive quantification of organ fat using a magnetic resonance approach includes: constructing a detection system; connecting a detection area; detection system startup; acquiring data; analyzing data; and performing horizontal data analysis. An external computer, a radio frequency (RF) subsystem, and a portable magnet module are used to construct a system for non-invasive quantification of organ fat based on low-field nuclear magnetic resonance (LF-NMR,), which causes no damage, and achieves accurate and non-invasive quantification of organ fat. Specific pulse sequences are used to excite nuclear spin in a target region to generate LF-NMR, so as to achieve “one-click” detection, which is used for fast screening of related diseases such as non-alcoholic fatty liver disease (NAFLD). The system has accurate quantification, and is easy to operate without constraints of operator qualifications.

The present disclosure provides a system and method for magnetic resonance imaging. The method may include obtaining a first set of imaging data, the first set of imaging data being sampled in multiple shots, each shot of the multiple shots corresponding to a plurality of echo times, the first set of imaging data including partially sampled data in a first k space; obtaining a second set of imaging data, the second set of imaging data including fully sampled data in a central region of a second k space; determining fitting data in the first k space based on the first set of imaging data and the second set of imaging data; and/or generating a target image based on the fitting data in the first k space and the first set of imaging data in the first k space.

Disclosed herein is a medical system (100, 300). The execution of machine executable instructions (120) causes a processor (104) to: receive (200) measured gradient echo k-space data (122); receive (202) an off-resonance phase map (124); reconstruct (204) an initial image (126) from the measured gradient echo k-space data; calculate (206) an upsampled phase map (128) from the off-resonance phase map; calculate (208) an upsampled image (130) from the initial image; calculating (210) a modulated image (132) by modulating the upsampled image with the upsampled phase map; calculate (212) a corrected image (134) comprising iteratively. The iterative calculation comprises: calculating (214) updated k-space data by applying a data consistency algorithm (138) to a k-space representation of the modulated image and the measured gradient echo k-space data and calculating (216) an updated image (142) from the updated k-space data. Calculation of the updated image comprises demodulation by the upsampled phase map and applying a smoothing algorithm.