Abstract: A system and method for enhanced contrast MR imaging include a computer programmed to perform a first scan of an imaging object based on a first fast spin echo (FSE) scan sequence comprising a first series of RF pulses having a first flip angle sequence to acquire a first MR data set and perform a second scan of the imaging object based on a second FSE scan sequence comprising a second series of RF pulses having a second flip angle sequence, wherein the second flip angle sequence is different from the first flip angle sequence to acquire a second MR data set. The computer is further programmed to generate a difference image based on the first and second MR data sets.

Abstract: A system and method for enhanced contrast MR imaging include a computer programmed to perform a first scan of an imaging object based on a first fast spin echo (FSE) scan sequence comprising a first series of RF pulses having a first flip angle sequence to acquire a first MR data set and perform a second scan of the imaging object based on a second FSE scan sequence comprising a second series of RF pulses having a second flip angle sequence, wherein the second flip angle sequence is different from the first flip angle sequence to acquire a second MR data set. The computer is further programmed to generate a difference image based on the first and second MR data sets.

Abstract: A method for calculating a flip angle schedule for a train of refocusing radio frequency (RF) pulses with reduced flip angles allows control of RF power deposition and use of a longer echo train. A target signal is defined for each echo in the echo train, and flip angles are then calculated from the target signals. The target signal schedule includes two phases. In the first phase, the target signals drop asymptotically to efficiently establish a pseudo-steady state at a pre-defined minimum signal level, Smin. In the second phase, the target signal is increased monotonically for the remainder of the train to a pre-defined maximum signal level, Smax. By increasing the target signal, the effect of relaxation may be reduced, decreasing blurring and ringing artifacts. Flip angles are then calculated from the target signal schedule, using a simplified method that requires no information about the tissues' relaxation properties.

Abstract: A method of magnetic resonance (MR) imaging includes segmenting a ky-kz plane comprising a plurality of encoding points into a plurality of annular segments. For each annular segment, a view ordering is defined based on a polar angle associated with each encoding point contained within the annular segment. MR data is acquired for the plurality of encoding points based on the view ordering for each annular segment and at least one MR image is generated using the acquired MR data.

Abstract: An apparatus and method for MR imaging in inhomogeneous magnetic fields includes acquisition of a plurality of three-dimensional (3D) MR data sets, each data set having a central transmit frequency and a central receive frequency set to a frequency offset that is distinct for each 3D MR data set. A composite image is generated based on the plurality of 3D MR data sets.

Abstract: A method for acquiring magnetic resonance (MR) data for a pulse sequence with periodic signal modulation and a set of views having at least two phase encode directions includes selecting a direction of modulation. Each view in the set of views is assigned a readout number based on a position of each view along the direction of modulation resulting in a plurality of readout number groups, each readout number group having a plurality of views. Each view within each readout number group is assigned a train number based on a position of each view along a second direction in k-space. MR data for the set of views is acquired based on the assigned readout number and train number for each view.

Abstract: A method of magnetic resonance (MR) imaging includes segmenting a ky-kz plane comprising a plurality of encoding points into a plurality of annular segments. For each annular segment, a view ordering is defined based on a polar angle associated with each encoding point contained within the annular segment. MR data is acquired for the plurality of encoding points based on the view ordering for each annular segment and at least one MR image is generated using the acquired MR data.

Abstract: A multi-shot three-dimensional (3D) magnetic resonance imaging (MRI) data view-ordering strategy for uniform or variable density k-space sampling schemes is presented. The ky-kz plane is partitioned into multiple wedge-shaped “blades” (or radial fan beams). The angular size of individual blades may be adjusted according to the desired number of views for each blade. Each blade includes views near the origin that contain low-frequency information about the imaged object such that views having the most desirable characteristics may be used to fill the central portions of k-space.

Abstract: A method for acquiring magnetic resonance (MR) data for a pulse sequence with periodic signal modulation and a set of views having at least two phase encode directions includes selecting a direction of modulation. Each view in the set of views is assigned a readout number based on a position of each view along the direction of modulation resulting in a plurality of readout number groups, each readout number group having a plurality of views. Each view within each readout number group is assigned a train number based on a position of each view along a second direction in k-space. MR data for the set of views is acquired based on the assigned readout number and train number for each view.

Abstract: An apparatus and method for MR imaging in inhomogeneous magnetic fields includes acquisition of a plurality of three-dimensional (3D) MR data sets, each data set having a central transmit frequency and a central receive frequency set to a frequency offset that is distinct for each 3D MR data set. A composite image is generated based on the plurality of 3D MR data sets.

Abstract: A multi-shot three-dimensional (3D) magnetic resonance imaging (MRI) data view-ordering strategy for uniform or variable density k-space sampling schemes is presented. The ky-kz plane is partitioned into multiple wedge-shaped “blades” (or radial fan beams). The angular size of individual blades may be adjusted according to the desired number of views for each blade. Each blade includes views near the origin that contain low-frequency information about the imaged object such that views having the most desirable characteristics may be used to fill the central portions of k-space.

Abstract: A method for calculating a flip angle schedule for a train of refocusing radio frequency (RF) pulses with reduced flip angles allows control of RF power deposition and use of a longer echo train. A target signal is defined for each echo in the echo train, and flip angles are then calculated from the target signals. The target signal schedule includes two phases. In the first phase, the target signals drop asymptotically to efficiently establish a pseudo-steady state at a pre-defined minimum signal level, Smin. In the second phase, the target signal is increased monotonically for the remainder of the train to a pre-defined maximum signal level, Smax. By increasing the target signal, the effect of relaxation may be reduced, decreasing blurring and ringing artifacts. Flip angles are then calculated from the target signal schedule, using a simplified method that requires no information about the tissues' relaxation properties.

Abstract: Methods and systems for generating T1-weighted images are provided. The method includes acquiring a pair of single-shot fast-spin-echo (SSFSE) images S1 and S2. The method further includes generating a T1-weighted image ST1w based on S1 and S2.

Abstract: A technique is set forth that is designed to reduce RF induced power in high field MR imaging that includes application of an initial contrast preserving phase of RF pulses. These initial RF pulses are designed to have a constant, relatively high flip angle over the initial contrast preserving phase. Following an effective TE, a ramp down phase is applied that has a limited number of RF pulses with a flip angle that is less than the flip angle of those in the initial contrast preserving phase. Further, the RF pulses in the ramp down phase have a flip angle that is decreased over the ramp down phase. This technique provides improved resolution and steady contrast and SNR, while significantly reducing induced RF power.

Abstract: An image acquisition using a spoiled, gradient-recalled echo imaging pulse sequence is preceded by a magnetization preparation sequence which rapidly drives longitudinal magnetization to the steady-state equilibrium level established by the imaging pulse sequence. The preparation sequence includes an RF saturation pulse followed by a recovery period (Trec) whose length is determined by the scan parameters of the imaging pulse sequence.

Abstract: An MRI system produces a series of real-time images by repeatedly acquiring image data and repeatedly reconstructing images from the acquired image data. The effective latency period between acquisition of the image data and display of the reconstructed images is minimized by acquiring image data in a reverse-centric view order in which low spatial frequencies are acquired last.