Described here are systems and methods for reconstructing images from multi-level sampled data acquired with a magnetic resonance imaging (MRI) system. An alternating direction method-of multipliers (ADMM) strategy is implemented for sparse reconstruction of multi-level sampled data, and which decomposes the reconstruction problem into simpler subproblems and enables certain operations to be computed once offline and recycled during the reconstruction process rather than repeated at every iteration. As one example, the described reconstruction technique enables sparse reconstruction of 3D contrast-enhanced MR angiogram time-series in just several minutes rather than the several hours previously required.

A magnetic resonance imaging apparatus according to an embodiment includes sequence control circuitry and processing circuitry. The sequence control circuitry executes a first pulse sequence and a second pulse sequence, the first pulse sequence including a first spoiler pulse serving as a dephasing gradient pulse of a first amount, the second pulse sequence including a second spoiler pulse serving as a dephasing gradient pulse of a second amount being different from the first amount or the second pulse sequence not including a spoiler pulse serving as a dephasing gradient pulse. The processing circuitry performs a subtraction operation between a first data obtained from the first pulse sequence and a second data obtained from the second pulse sequence, thereby generating an image.

A method for processing images of lungs, the method comprising defining an inhale region of interest of the lungs at an inhale position and an exhale region of interest of the lungs at an exhale position, determining a spatial transformation of each voxel within the lungs between the lungs at the inhale position and the lungs at the exhale position to provide displacement vector estimates for each voxel within the lungs, and performing volume change inference operations to determine a volume change between the lungs at the inhale position and the lungs at the exhale position based on the inhale region of interest, the exhale region of interest, and the displacement vector estimates for each voxel within the lungs.

A magnetic resonance imaging method according to an embodiment includes performing a balanced SSFP sequence, repeatedly applies an excitation RF pulse to a subject at intervals of a repetition time and applies gradient magnetic field pulses balanced such that a time integral becomes zero within each interval of the repetition time, while further applying a spin labeling gradient magnetic field for generating one or more continuous spin labels within each interval of the repetition time.

An object (10) is placed in an examination volume of a MR device (1). To enable fast MR imaging, a stack-of-stars acquisition scheme is employed with a reduced level of streaking artifacts. The acquisition scheme includes subjecting the object (10) to an imaging sequence of at least one RF pulse and switched magnetic field gradients and acquiring MR signals according to the stack-of-stars scheme. The MR signals are acquired as radial k-space profiles (S1-S12) from a number of parallel slices (21-27) arranged at different positions along a slice direction. The radial density of the k-space profiles (S1-S12) varies as a function of the slice position with the radial density being higher at more central k-space positions and lower at more peripheral k-space positions. The k-space profiles are acquired at a higher temporal density from slices at the more central positions than from slices at the more peripheral k-space positions. An MR image is reconstructed from the MR signals.

The present disclosure provides methods and systems for high-resolution functional magnetic resonance imaging (fMRI), including real-time high-resolution functional MRI methods and systems.

Method of determining a velocity profile of a fluid flowing through a conduit, the method including applying a saturation pulse on spins of magnetic field-sensitive nuclei in the fluid, measuring a signal of the fluid to determine position of the magnetic field-sensitive nuclei, the measurement carried out at a recovery time TR and at a distance d within the conduit, determining within the conduit a radial distance r characterized by a local minimum in the measured signal, wherein the radial distance r is measured from the center of the conduit, and determining a velocity profile of the fluid at the radial distance, based on the magnetic field-sensitive nuclei.

A method for MRI includes performing an MRI experiment on a material to acquire an echo attenuation data set using a gradient modulation scheme comprising 1D diffusion encoding and to acquire an echo attenuation data set using a gradient modulation scheme comprising 2D diffusion encoding, determining respective first-order deviations .sub.2 from mono-exponential decay in said echo attenuation data sets, and generating MRI parameter maps or MR image contrast based on said first-order deviations .sub.2.

The invention pertains to advances in constructing predetermined magnets from appropriate magnetic material that allows for focusing the magnetic field in a target region.

The invention relates to a motion determination device for determining the motion of an object. The motion determination device comprises a magnetic resonance (MR) information providing unit (2, 5) for providing an MR image of the object (6) and for providing non-image MR data of the object which have been acquired at different acquisition times, and a motion determination unit (9) for determining a motion field, which describes the motion of the object (6), depending on the provided non-image MR data acquired at the different acquisition times and the provided MR image. Since the non-image MR data, which are preferentially k-space data, are directly used for determining the motion field, i.e. without an intermediate reconstruction of MR images based on the non-image MR data, the motion field can be determined with a very high temporal resolution.