Patent classifications
G01R33/5616
3D OSCILLATING GRADIENT-PREPARED GRADIENT SPIN-ECHO IMAGING METHOD, AND DEVICE
A method for 3D oscillating-gradient prepared gradient spin-echo imaging and a device. The imaging method comprises the following steps: first, using a global saturation module to destroy previous residual transverse magnetization; second, embedding a pair of trapezoidal cosine oscillating gradients into a 90°.sub.x-180°.sub.y-90°.sub.−x radiofrequency pulse by a diffusion encoding module, to separate diffusion encoding from signal acquisition; then, using a fat saturation module to suppress a fat signal; finally, acquiring a signal by means of gradient spin-echo readout, and correcting phase errors among multiple excitations by multiplexed sensitivity-encoding reconstruction. Compared with a 2D plane echo-based oscillating gradient diffusion sequence used on a 3T clinical system, a 3D oscillating-gradient prepared gradient spin-echo sequence effectively reduces the imaging time, improves the signal to noise ratio, and is beneficial to clinical transformation of time-dependent diffusion MRI technology
MRI APPARATUS AND NON-TRANSITORY COMPUTER-READABLE STORAGE MEDIUM
An MRI apparatus includes a scanner configured to apply an RF pulse to an object and processing circuity configured to: set a first pulse sequence in which acquisition of a first set of MR signals is started after a first delay time from application of a first excitation pulse, and a second pulse sequence in which acquisition of a second set of MR signals is started after a second delay time from application of a second excitation pulse, the second delay time being different from the first delay time; acquire first and second sets of MR signals by causing the scanner to apply the first and second pulse sequences to the object; generate a combined dataset by averaging a first dataset based on the first set of MR signals and a second dataset based on the second set of MR signals; and reconstruct an MR image based on the combined dataset.
A MAGNETIC RESONANCE METHOD, SOFTWARE PRODUCT, AND SYSTEM FOR DETERMINING A DIFFUSION PROPAGATOR OR RELATED DIFFUSION PARAMETERS FOR SPIN-LABELLED PATRICLES
The present disclosure relates to a computer implemented diffusion magnetic resonance method for determining a diffusion parameter for spin-labelled particles in a specimen. The method (100) comprises providing (110) a specimen and a magnetic resonance device arranged to measure magnetic resonance in said specimen; applying (120) at least one magnetic field gradient pulse sequence to said specimen, thereby spin-labelling a set of particles comprised in said specimen; obtaining (130) magnetic resonance measurement data corresponding to said at least one magnetic field gradient pulse sequence for said spin-labelled particles with said magnetic resonance device; determining (140) at least one diffusion parameter for said spin-labelled particles based on said obtained measurement data; wherein determining (140) said at least one diffusion parameter comprises forming for each diffusion parameter at least one Fourier transform representing said diffusion parameter based on said obtained measurement data; and wherein each magnetic field gradient pulse sequence comprises at least three gradient pulses wherein at least one gradient pulse is configured to introduce a phase shift in said spin-labelled particles based on their position in said specimen.
Continuous Three-Dimensional Imaging for Magnetic Resonance Elastography
Described here are systems and methods for a robust magnetic resonance elastography (“MRE”) imaging platform for rapid dynamic 3D MRE imaging. The imaging platform includes an MRE pulse sequence and advanced image reconstruction framework that work synergistically in order to greatly expand the domains where MRE can be deployed successfully.
MULTIPLEX MRI IMAGE RECONSTRUCTION
In Multiplex MRI image reconstruction, a hardware processor acquires sub-sampled Multiplex MRI data and reconstructs parametric images from the sub-sampled Multiplex MRI data. A machine learning model or deep learning model uses the subsampled Multiplex MRI data as the input and parametric maps calculated from the fully sampled data, or reconstructed fully sample data, as the ground truth. The model learns to reconstruct the parametric maps directly from the subsampled Multiplex MRI data.
SYSTEM AND METHOD FOR QUANTITATIVE MAPPING WITH MAGNETIC RESONANCE IMAGING
A system and method are provided for producing at least one of an image or a map of a subject includes controlling a magnetic resonance imaging (MRI) system to perform a pulse sequence that includes a phase increment of an RF pulse selected to induce a phase difference between two echoes at different echo times (TE). The method also includes controlling the MRI system to acquire MR data corresponding to at least the two echoes at different TEs, deriving a static magnetic field (B0) map of the MRI system using the MR data corresponding to the two echoes, and using the B0 map and MR data from at least one of the two echoes, generate a map of T2 of the subject.
Method for acquiring measurement data using a magnetic resonance system with correction of k-space trajectories
In a method for acquiring measurement data using a magnetic resonance (MR) system having a gradient unit, frequency-dependent parameters characterizing the gradient unit of the MR system are accessed (e.g. loaded from a memory), a k-space trajectory of a RESOLVE (Readout Segmentation Of Long Variable Echo trains) sequence planned for a MR measurement is accessed, MR measurement data is acquired based on the planned k-space trajectory and reconstructing image data from the MR measurement data, and an electronic signal is provided that represents the reconstructed image data as an output of the MR system. The k-space trajectory may have a frequency component in at least one direction. The planned k-space trajectory may be corrected based on at least one frequency component of the planned k-space trajectory and the frequency-dependent parameters.
Systems And Methods For Simultaneously Measuring Diffusion Weighted Spin-Echo And Stimulated Echo Signals
A method for applying a diffusion-weighting gradient during acquisition of diffusion-weighted imaging signals from a selected portion of a nervous system of a subject. Planar diffusion-weighted spin-echo (DWSE) imaging signals and planar diffusion-weighted stimulated-echo (DWSTE) imaging signals can be obtained to provide a plurality of sets of imaging signals. At least one set of imaging signals includes DWSTE signals that are associated with a high-b-value. A signal difference between DWSE imaging signals and DWSTE imaging signals can be corrected based on respective sets of DWSE imaging signals and DWSTE imaging signals having b-values at or near zero.
Method for creating diffusion-weighted and non-diffusion-weighted scan data by means of magnetic resonance
Techniques are disclosed for capturing scan data of an examination object via a magnetic resonance system. The techniques include capturing a first set of a diffusion-weighted scan data by excitation and, in an acquisition phase, acquiring a first echo signal, wherein before the acquisition phase in a diffusion preparation phase, diffusion gradients are switched for diffusion encoding of the scan data, The techniques additionally include capturing a second set of non-diffusion-weighted scan data by excitation and, in an acquisition phase, acquiring a second echo signal, wherein before the acquisition phase, in a diffusion preparation phase, the same diffusion gradients are switched as are switched for diffusion encoding of the scan data of the first set of diffusion-weighted scan data, although they have no influence on the second echo signal. Diffusion-weighted and non-diffusion-weighted scan data is thereby captured, having identical disturbances caused by eddy currents induced by switched gradients.
3D flow compensated interleaved epi in combination with swapped readout
The disclosure relates to a fast susceptibility imaging techniques for performing flow compensations in the slice, phase, and frequency encoding directions for the central echo of a plurality of echoes excited each time in interleaved echo planar imaging (iEPI). The echo data for which flow compensations have been performed may be collected, and susceptibility-weighted imaging (SWI) performed for collected echo data. The fast susceptibility imaging techniques may reduce scan time.