University of California

General Electric Company

Jiang Du

Michael Carl

Yajun Ma

Mark Bydder

Graeme M Bydder

Hyungseok Jang

Disclosed are methods and systems for ultrashort echo time magnetization transfer (UTE-MT) imaging and signal modeling to quantify the different proton groups, including free water, bound water and macromolecule protons in short T2 tissues such as the menisci, ligaments, tendons and cortical bone. UTE-MT images with a series of MT frequency offsets and MT power are subject to MT modeling to evaluate T1s, T2s, fractions and exchange rates of bound water, free water and macromolecule protons.

Systems and methods for ultrashort echo time magnetization transfer (UTE-MT) imaging and signal modeling

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.

System and method for magnetic resonance imaging a subject via a hybrid encoding scheme

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.

Systems and methods for ultrashort echo time actual flip angle imaging and variable repetition time magnetic resonance imaging

A method for performing magnetic resonance imaging of an object is provided. The method includes acquiring MR signals from the object via an MRI system, and generating correct T2 values and incorrect spin densities by applying a fitting model to the MR signals. The method further includes generating one or more correction factors, and generating corrected spin densities based at least in part on the incorrect spin densities and the one or more correction factors. The one or more correction factors are based at least in part on the correct T2 values and a bandwidth of a fat suppression signal applied to the object.

System and method for performing T2 magnetic resonance imaging of an object with fat suppression

Methods, systems, and apparatus for magnetic resonance imaging (MRI) are described. In one example, the method includes applying a sample-selective magnetic field gradient sequence along a slice direction to partition responses from a sample under magnetic resonance imaging into a plurality of different regions of slices in the k space, applying spiral readout gradients to the sample to obtain echo data from the sample, and applying a Time Resolved Imaging of Contrast Kinetics imaging technique to sample the different regions of slices in the k space.

Magnetic resonance imaging with high spatial and temporal resolution

Methods, systems and computer program products of magnetic resonance imaging (MRI) using ultra short echo times and spiral sampling in k-space are disclosed. A long inversion radio frequency (RF) pulse that inverts magnetization of long Tcomponents are applied to a sample that exhibits long transverse relaxation time (T) components and short Tcomponents to minimize signals corresponding to the long Tcomponents. In addition, half RF excitation pulses are applied to the sample to select one or more echo times. Data corresponding to the selected one or more echo times are acquired using a spiral trajectory, and a first echo image is obtained based on the acquired data.

Magnetic resonance imaging (MRI) using ultra short echo times and spiral sampling in K-space

Techniques and systems for magnetic resonance imaging are disclosed in this specification. In one aspect, imaging of tissues having short transverse relaxation times Tis described including short echo time (TE) signal acquisition preceded by suppression of signal from the surrounding tissues having long transverse relaxation times T, to increase the contrast and dynamic range of magnetic resonance (MR) images contributed by the tissues having short T

Selective magnetic resonance imaging

The techniques and systems described in this application can be used to, in one implementation, optimize data acquisition including sampling trajectories and undersampling factors. A method performed by a nuclear magnetic resonance imaging (MRI) system comprises applying a gradient and a radio frequency pulse sequence to an imaging target to partition a three-dimensional (3D) Cartesian k-space into a plurality of half projections in a ky-kz plane, the plurality of half projections divided into a plurality of interleaves, each interleave comprising one or more of the half projections and providing an asymmetric radial sampling of the ky-kz plane. Magnetic resonance signals are acquired to sample phase and slice encodings along each of the plurality of half projections. The magnetic resonance signal is processed to reconstruct at least one dynamic frame of the imaging subject to provide 3D volumetric imaging of contrast dynamics.

Time-resolved contrast-enhanced magnetic resonance (MR) angiography

Radio frequency (rf) pulses are applied to a sample to produce magnetic resonance (MR) echo signals from the sample at multiple different echo times. Magnetic field gradients are applied to the sample to select for acquisition components of each MR echo signal. The selected components correspond to groups of radial projections in k-space. Each group is associated with one of the echo times. Each group defines a different set of projection angles in the k-space, and the groups are interleaved to reduce streak artifacts in spectroscopic images associated with a resonance frequency. Images of the sample are generated based on acquired MR signals. In some implementations, an echo time of eight microseconds or less is included in the multiple different echo times.

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San Diego, CA, United States of America

Jiang Du