In a method for determining a normalized MR relaxation parameter for an object using an imaging sequence where the MR signal of the object under examination is detected at a first echo time and at a second echo time, a first MR signal for the object under examination obtained at the first echo time is determined, a second MR signal for the object under examination obtained at the second echo time is determined, a first reference MR signal obtained at the first echo time from a reference tissue having a known value for the MR relaxation parameter is determined, a second reference MR signal obtained at the second echo time from the reference tissue is determined, and the normalized MR relaxation parameter is calculated based on the first MR signal, the second MR signal, the first echo time, the second echo time, and the first and second reference MR signal.

In a method and magnetic resonance (MR) apparatus for echo-planar acquisition of MR images using multiple reception coils, an RF excitation pulse is radiated to generate transverse magnetization, and a temporal sequence of a readout gradient is activated with alternating positive and negative values, thereby producing MR signal echoes. Multiple phase-encoding gradients are activated in a temporal sequence with a value of the phase-encoding gradients being maximum when a value of the readout gradients is minimum, and vice versa. A time period during which a single phase-encoding gradient is applied is at least a quarter of a time interval between two MR signal echoes. The MR signal echoes are read with the multiple reception coils in a trajectory in k-space, continuously without interruption during the readout gradient. The trajectory does not completely fill k-space with raw data in an edge region according to the Nyquist condition.

Disclosed are systems and methods for accurately measuring T1 in magnetic resonance imaging (MRI) for short T2 tissues by an integrative three-dimensional Ultrashort Echo Time Actual Flip Angle Imaging Variable TR (3D UTE-AFI-VTR) technique. Also, disclosed are systems and methods for accurately measuring T1 for T2 tissues by an integrative three-dimensional Ultrashort Echo Time Actual Flip Angle Imaging Variable Flip Angle (3D UTE-AFI-VFA) technique. The disclosed methods and systems can be implemented to allow accurate T1 mapping for T2 tissues, including menisci, ligaments, tendons, myelin in gray and white matter, cortical bone, and soft tissue in whole joints.

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 using bipolar readout magnetic field gradients and avoids flow-induced leaking and swapping artifacts. According to the invention, an object (10) is subjected 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). The echo signals are acquired from the object (10) using bipolar readout magnetic field gradients. A first single echo image is reconstructed from the first echo signals and a second single echo image is reconstructed from the second echo signals. A zero echo time image is computed by extrapolating the phase of the first single echo image at each voxel position to a zero echo time using the phase difference between the first and the second single echo image at the respective voxel position. Flow-induced phase errors are identified and estimated in the zero echo time image, and the phase of the first single echo image is corrected according to the estimated flow-induced phase errors. Finally, a water image and/or a fat image are reconstructed from the echo signals, wherein signal contributions from water and fat to the echo signals are separated using the phase-corrected first single echo image and the second single echo image. Moreover, the invention relates to a MR device (1) and to a computer program to be run on a MR device (1).

A system for magnetic resonance imaging a subject is provided. The system includes a magnet assembly and a controller. The controller is in electronic communication with the magnet assembly and operative to: perform an inversion recovery pulse on the subject via the magnet assembly; acquire an ultrashort echo from the subject via the magnet assembly using a hybrid encoding scheme; and generate an image of the subject based at least in part on the ultrashort echo.

A low-field magnetic resonance imaging (MRI) system. The system includes a plurality of magnetics components comprising at least one first magnetics component configured to produce a low-field main magnetic field B.sub.0 and at least one second magnetics component configured to acquire magnetic resonance data when operated, and at least one controller configured to operate one or more of the plurality of magnetics components in accordance with at least one low-field zero echo time (LF-ZTE) pulse sequence.

A magnetic resonance (MR) image is created by executing an imaging sequence with an MR apparatus, wherein data in k-space are acquired using multiple receiving antennae, and reconstruction of all image points that correspond to all k-space points belonging to the imaging sequence takes place using a sensitivity profile of the receiving antennae in order to also take account of data at k-space points at positions at which no data were acquired. Data acquired at a number of positions of particular k-space points, the number of the particular k-space points being smaller than the number of all k-space points belonging to the imaging sequence. The aperture of each of the receiving antennae is configured such that, for acquisition of data at a respective k-space point, the spectral main lobe of the respective receiving antenna also extends over k-space points adjacent to the respective k-space point.

A method for generating a magnetic resonance image includes applying a radio frequency (RF) pulse to a specimen. The method includes modulating a spatially varying magnetic field to impart an angular velocity to a trajectory of a region of resonance relative to the specimen. The method includes acquiring data corresponding to the region of resonance and reconstructing a representation of the specimen based on the data.

A medical apparatus (300, 400, 500) includes a magnetic resonance imaging system (302) for acquiring magnetic resonance data (342) from an imaging zone (308); a processor (330) for controlling the medical apparatus; a memory (336) storing machine executable instructions (350, 352, 354, 356). Execution of the instructions causes the processor to: acquire (100, 200) the magnetic resonance data using a pulse sequence (340) which specifies an echo time greater than 400 s; reconstruct (102, 202) a magnetic resonance image using the magnetic resonance data; generate (104, 204) a thresholded image (346) by thresholding the magnetic resonance image to emphasize bone structures and suppressing tissue structures in the magnetic resonance image; and generate (106, 206) a bone-enhanced image by applying a background removal algorithm to the thresholded image.

The present invention relates to a method for side-band suppression in a Magnetic Resonance imaging, MRI, system (100), the method comprising providing a first multiband RF pulse for simultaneously exciting at least two slices in a subject (118) at a first and a second frequency band (301,303) and to acquire using the MRI system (100) signals (307, 308) from the excited two slices and at least one additional signal (309) at a third frequency band (305), the additional signal (309) resulting from a sideband excitation of a slice different from the two slices; using the first multiband RF pulse for determining the additional signal (309); deriving a pre-compensating term from the first multiband RF pulse and the additional signal (309), adding the pre-compensating term to the first multiband RF pulse to obtain a second multiband RF pulse, thereby replacing the first multiband RF pulse by the second multiband RF pulse for suppressing at least part of the additional signal (309).