Abstract: Systems and methods for accelerated magnetic resonance imaging using a tilted reconstruction kernel to synthesize unsampled k-space data in phase encoded and point spread function (“PSF”) encoded k-space data are provided. Images reconstructed from the data have reduced B0-related distortions and reduced T2* blurring. In general, data are acquired with systematically optimized undersampling of the PSF and phase encoding subspace. Parallel imaging reconstruction is implemented with a B0 inhomogeneity informed approach to achieve greater than twenty-fold acceleration of the PSF encoding dimension. A tilted reconstruction kernel is used to exploit the correlations in the phase encoding-PSF encoding subspace.

Abstract: A computer-implemented method for reconstructing a MRI image, including: receiving a plurality of MRI measurement data sets f1 to fN, wherein each data set is acquired from an examination object based on a different MRI protocol of an MRI system; receiving MRI images u10 to uN0 corresponding to the MRI measurement data sets f1 to fN; applying, in at least a first step GD1, trained functions to the MRI images u10 to uN0, using a neural network and a forward-sampling operator, wherein at least one output MRI image uT is generated; and providing the at least one output MRI image uT, wherein the forward-sampling operator determines an agreement between at least one MRI image u10 to uN0 and the corresponding MRI measurement data set f1 to fN.

Abstract: A method includes determining an initial magnetic resonance imaging, MRI, dataset (201) in image domain based on an initial reconstruction of MRI measurement data obtained using an undersampling scheme (400); and determining patches (231-233) of the initial MRI dataset (201) in accordance with a patching scheme, the patching scheme depending on the undersampling scheme (400); and, for each one of the patches (231-233): applying a machine-learned algorithm to obtain a respective patch (231-233) of a reconstructed MRI dataset, the machine-learned algorithm depending on the undersampling scheme (400); and combining the patches (231-233) of the reconstructed MRI dataset.

Abstract: Systems and methods for performing diffusion-weighted magnetic resonance imaging (“MRI”), including reconstructing and analyzing images, while preserving phase information that is traditionally discarded in such applications, are provided. For instance, background phase variations are eliminated, which enables complex-valued data analysis without the usual noise bias. As a result, the systems and methods described here provide an image reconstruction that enables true signal averaging, which increases signal-to-noise ratio (“SNR”) and allows higher contrast in diffusion model reconstructions without a magnitude bias.

Abstract: A magnetic resonance fingerprinting (“MRF”) framework that implements simultaneous multislice acquisition techniques with a Hadamard RF-encoding to simultaneously acquire magnetic resonance data from multiple slices simultaneously is described. As one non-limiting example, magnetic resonance data can be simultaneously acquired from four different slices. In other embodiments, however, the Hadamard encoding can be condensed into one or two acquisitions, rather than four.

Abstract: Described here are systems and methods for producing images of a subject using magnetic resonance imaging (“MRI”) in which data are acquired using a sparse approximate encoding scheme for controlled aliasing techniques. As one example, the sparse approximate encoding can be used for a Wave-CAIPI encoding scheme, which can enable faster image reconstruction using fewer computational resources, in addition to reducing noise in the reconstructed images relative to those reconstructed from data acquired using a Wave-CAIPI encoding scheme without sparse approximate encoding.

Abstract: Systems and methods for accelerated diffusion-weighted magnetic resonance imaging using a tilted reconstruction kernel to synthesize unsampled k-space data in phase encoded and point spread function (“PSF”) encoded k-space data are provided. Images reconstructed from the data have reduced B0-related distortions and reduced T2* blurring. In general, data are acquired with systematically optimized undersampling of the PSF and phase encoding subspace. Parallel imaging reconstruction is implemented with a B0 inhomogeneity informed approach to achieve greater than twenty-fold acceleration of the PSF encoding dimension. A tilted reconstruction kernel is used to exploit the correlations in the phase encoding-PSF encoding subspace. Self-navigated phase corrections are computed from the acquired data and used to synthesize the unsampled k-space data.

Abstract: Systems and methods for accelerated magnetic resonance imaging using a tilted reconstruction kernel to synthesize unsampled k-space data in phase encoded and point spread function (“PSF”) encoded k-space data are provided. Images reconstructed from the data have reduced B0-related distortions and reduced T2* blurring. In general, data are acquired with systematically optimized undersampling of the PSF and phase encoding subspace. Parallel imaging reconstruction is implemented with a B0 inhomogeneity informed approach to achieve greater than twenty-fold acceleration of the PSF encoding dimension. A tilted reconstruction kernel is used to exploit the correlations in the phase encoding-PSF encoding subspace.

Abstract: Systems and methods for magnetic resonance imaging (“MRI”) that address the geometric distortions and blurring common to conventional echo planar imaging (“EPI”) sequences, and that provide new temporal signal evolution information across the EPI readout, are described. Echo planar time-resolved imaging (“EPTI”) schemes are described to implement an accelerated sampling of a hybrid space spanned by the phase encoding dimension and the temporal dimension. In general, each EPTI shot covers a segment of this hybrid space using a zigzag trajectory with an interleaved acceleration in the phase-encoding direction. The hybrid space may be undersampled and a tilted reconstruction kernel used to synthesize additional data samples.

Abstract: Systems and methods for simultaneous multislice (“SMS”} magnetic resonance imaging (“MRI”}, in which a random blip gradient encoding scheme is utilized to impart a different phase to each of a plurality of different slice locations. Because of the random blip gradient encoding, the amount of the imparted phase is randomized for each phase encoding step in a Cartesian k-space trajectory. This data acquisition strategy leads to incoherent aliasing artifacts across the simultaneously excited slices. Images of the individual slices can be reconstructed using a compressed sensing framework.

Abstract: A method for maximizing the signal-to-noise ratio (“SNR”) in a combined image produced using a parallel magnetic resonance imaging (“MRI”) technique is provided. The image combination used in such techniques require an accurate estimate of the noise covariance. Typically, the thermal noise covariance matrix is used as this estimate; however, in several applications, including accelerated parallel imaging and functional MRI, the noise covariance across the coil channels differs substantially from the thermal noise covariance. By combining the individual channels with more accurate estimates of the channel noise covariance, SNR in the combined data is significantly increased. This improved combination employs a regularization of noise covariance on a per-voxel basis.

Abstract: Techniques are disclosed to leverage the use of neural networks or similar machine learning algorithms to de-noise highly accelerated Wave-CAIPIRINHA scans. The described techniques facilitate the generation of 3D sequences using a greatly reduced scan time, with the resulting images having a high spatial resolution and an improved SNR compared to conventional approaches.

Abstract: Systems and methods for estimating the actual k-space trajectory implemented when acquiring data with a magnetic resonance imaging (“MRI”) system while jointly reconstructing an image from that acquired data are described. An objective function that accounts for deviations between the actual k-space trajectory and a designed k-space trajectory while also accounting for the target image is optimized. To reduce the computational burden of the optimization, a reduced model for the parameters associated with the k-space trajectory deviation and the target image can be implemented.

Abstract: Systems and methods for controlling a magnetic resonance imaging (MRI) system to simultaneously excite multiple different slice locations. A multiband (MB) radio frequency (RF) pulse waveform is combined with an RF pulse waveform that results in periodic excitation of the slice locations, such as a power independent of a number of slices (PINS) RF pulse waveform. Before combination, the MB RF pulse waveform is preferably transformed to traverse the excitation k-space trajectory defined by a plurality of slice-encoding gradient blips. The combined RF pulse waveform is used to generate an RF excitation field generated while the plurality of slice-encoding gradient blips are played out. The portions of the combined RF pulse associated with the MB RF pulse are played out during the gradient blips, and the portions associated with the PINS RF pulse are played out between the gradient blips.

Abstract: Described here are systems and methods for using excited slice profiles to improve the point spread function (“PSF”) of super-resolution slices in SLIDER acquisitions while preserving all of the advantages of the SLIDER technique. The techniques described here may generally be referred to as “Generalized SLIDER” (“g-SLIDER”).

Abstract: Systems and methods for a hierarchical mapping framework (“HMF”} for coil compression are provided. The HMF-based coil compression can be applied to existing coil compression algorithms to improve their performance. The receive channels associated with a coil array are divided into subgroups based on the strength of their mutual correlation. In each subgroup, one or more virtual channels are produced based on the channels not in the subgroup. The virtual channels are produced using a coil compression algorithm subject to a hierarchically semiseparable channel mixing across the subgroups. Images are reconstructed for the subgroups and then combined to produce the final image of the subject.

Abstract: A system and method for producing high resolution diffusion information and imaging from a subject. In some aspects, the method includes receiving a plurality of low resolution diffusion images, each acquired with a different set of gradient directions and shifted in a slice direction, and generating a model correlating diffusion signals associated with the plurality of low resolution diffusion images and a high resolution diffusion image. The method also includes reconstructing the high resolution diffusion image by minimizing a cost function determined using the model. In some applications, the method further includes processing the high resolution diffusion image to generate a report providing diffusion information associated with the subject.

Abstract: Systems and methods for reconstructing magnetic resonance (MR) tissue parameter maps of a subject from magnetic resonance fingerprinting (MRF) data acquired using a magnetic resonance imaging (MRI) system. The method includes providing MRF data acquired from a subject using an MRI system and performing an iterative, maximum-likelihood reconstruction of the MRF data to create MR tissue parameter maps of the subject.

Abstract: Systems and methods for combined ghost artifact correction and parallel imaging reconstruction of simultaneous multislice (“SMS”) magnetic resonance imaging (“MRI”) data are provided. Dual-polarity training data are used to generate ghost-free slice data, which are used as target data in a reconstruction kernel training process. The training data are used as source data in the reconstruction kernel training. As a result, reconstruction kernels are computed, which can be used to reconstruct images from SMS data in which slice-specific ghosting artifacts are removed.

Abstract: A method for imaging a subject with a magnetic resonance imaging (MRI) system using controlled aliasing is provided. A radio frequency (RF) excitation field is applied to excite the spins in a volume-of-interest that may include multiple slice locations. Using the MRI system, a readout magnetic field gradient is established following the application of the RF excitation field to form echo signals. These echo signal receive a differential encoding by way of establishing, while the readout gradient is established, alternating magnetic field gradients along two directions, such as the partition-encoding and phase-encoding directions. Image data is acquired from the formed echo signals and images of the subject are reconstructed from the acquired image data.