A system and method for simultaneous multi-slice nuclear spin tomography is provided which requires no sensitivity profile of a receiving coil along a slice axis. A pulse space region to be sampled can be specified. A first pulse space dimension (k.sub.y) can be assigned to a first phase-encoded axis and a second pulse space dimension (k.sub.z) can be assigned to a second phase-encoded axis and the second phase-encoded axis corresponds to the slice axis. A sampling scheme can also be specified, and a complete sampled can be provided along the second pulse space dimension (k.sub.z). A magnetic resonance scan can then be carried out within the pulse space region to be sampled based on the sampling scheme and respective phase-encodings of the first and second phase-encoded axis.

In a method and apparatus for acquiring magnetic resonance (MR) raw data, an MR data acquisition scanner is operated to execute a turbo spin echo (TSE) or a turbo gradient spin echo (TGSE) sequence wherein nuclear spins are excited in multiple slices of the examination object simultaneously by radiating at least one radio-frequency (RF) pulse from an RF radiator of the MR data acquisition scanner, thereby causing the excited nuclear spins in said multiple slices to produce an echo train. A multi-band refocusing pulse is radiated that refocuses nuclear spins in at least one of said multiple slices that follows a first of the multiple slices, and readout gradients are activated to acquire MR signals, with respectively different contrasts, at respectively different readout times of the echo train. The read out MR signals are entered into an electronic memory organized as k-space.

An IR pulse is applied to a tag region B that is disposed at the upstream side of the ascending aorta relative to a tag region A at a timing with a second predetermined delay time TD2 (for example, 600 ms) from the application time of an IR pulse to the tag region A to thereby perform tagging. By this tagging, it is possible to suppress the MR signals derived from the substantial portions and the blood within the tag region B. Subsequently, an imaging scan is performed after a predetermined time lapse TIA (for example, 1200 ms) from the application time of the IR pulse to the tag region A or after a predetermined time lapse TIB (for example, 600 ms) from the application time of the IR pulse to the tag region B.

The present invention provides a magnetic resonance imaging system for imaging a subject by a multi-shot imaging. The magnetic resonance imaging system comprises an acquiring unit for acquiring MR raw data corresponding to a plurality of shots; an imaging unit for generating a plurality of folded images from the MR raw data, wherein each of the plurality of folded images is generated from a subset of the MR raw data; a deriving unit for deriving magnitude of each pixel of each folded image; a detecting unit for detecting a motion of the subject during the multi-shot imaging based on similarity measurements of any two folded images of the plurality of folded images, wherein the detecting unit further comprises a first deriving unit configured to derive the measured similarities; and a reconstructing unit for reconstructing a MR image of the subject based on MR raw data obtained according to a detection result of the detecting unit. Since the partially acquired MR raw data is used for motion detection directly, it would be more rapid and stable.

A method of performing multi-slice acceleration for MR fingerprinting includes obtaining k-space data for MR volumes; applying controlled radio frequency (RF) pulses to the MR volumes; exciting a plurality of slices within the MR volumes by the RF pulses at a same time; and producing a plurality of fingerprints from the plurality of slices. At least one set of fingerprints is compressed, and a residual signal of a plurality of signal evolutions is reduced. The method additionally includes periodically switching a weighting between a first slice and a second slice of the plurality of slices.

The present invention provides a magnetic resonance imaging system for imaging a subject by a multi-shot imaging. The magnetic resonance imaging system comprises an acquiring unit for acquiring MR raw data corresponding to a plurality of shots; an imaging unit for generating a plurality of folded images from the MR raw data, wherein each of the plurality of folded images is generated from a subset of the MR raw data; a deriving unit for deriving magnitude of each pixel of each folded image; a detecting unit for detecting a motion of the subject during the multi-shot imaging based on similarity measurements of any two folded images of the plurality of folded images, wherein the detecting unit further comprises a first deriving unit configured to derive the measured similarities; and a reconstructing unit for reconstructing a MR image of the subject based on MR raw data obtained according to a detection result of the detecting unit. Since the partially acquired MR raw data is used for motion detection directly, it would be more rapid and stable.

A method for providing an estimated 3D T.sub.2 map for magnetic resonance imaging using a Double-Echo Steady-State (DESS) sequence for a volume of an object in a magnetic resonance imaging (MRI) system is provided. A DESS scan of the volume is provided by the MRI system. Signals S.sub.1 and S.sub.2 are acquired by the MRI system. Signals S.sub.1 and S.sub.2 are used to provide a T.sub.2 map for a plurality of slices of the volume, comprising determining repetition time (TR), echo time (TE), flip angle α, and an estimate of the longitudinal relaxation time (T.sub.1), and wherein the DESS scan has a spoiler gradient with an amplitude G and a duration τ and ignoring echo pathways having spent more than two repetition times in the transverse plane.

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.

A magnetic resonance imaging (MRI) method includes defining a plurality of sub-volumes so that each of the sub-volumes includes a plurality of sequential slices of a plurality of slices that make up a volume of a subject, wherein the sub-volumes are divided into a plurality of groups so that any neighboring sub-volumes belong to different groups; applying radio-frequency (RF) pulses including a plurality of frequency components and a selection gradient to the subject to simultaneously excite a plurality of sub-volumes in each of the groups; performing three-dimensional (3D) encoding on each of the excited sub-volumes so that only some slices of the plurality of slices in each of the excited sub-volumes are encoded in a slice direction; acquiring magnetic resonance signals from the encoded sub-volumes; and reconstructing the acquired magnetic resonance signals into image data corresponding to each of the plurality of slices in each of the encoded sub-volumes.

For determination of motion artifact in MR imaging, motion of the patient in three dimensions is used with a measurement k-space line order based on one or more actual imaging sequences to generate training data. The MR scan of the ground truth three-dimensional (3D) representation subjected to 3D motion is simulated using the realistic line order. The difference between the resulting reconstructed 3D representation and the ground truth 3D representation is used in machine-based deep learning to train a network to predict motion artifact or level given an input 3D representation from a scan of a patient. The architecture of the network may be defined to deal with anisotropic data from the MR scan.