Abstract: Some aspects of the present disclosure relate to accelerated imaging using variable-density sampling and compressed sensing with parallel imaging. In one embodiment, a method includes acquiring magnetic resonance data associated with a physiological activity in an area of interest of a subject. The acquiring includes performing accelerated variable-density sampling with phase-contrast displacement encoding. The method also includes reconstructing, from the acquired magnetic resonance data, images corresponding to the physiological activity in the area of interest. The reconstructing includes performing parallel imaging and compressed sensing.

Abstract: Some aspects of the present disclosure relate to systems and methods for accelerated dynamic magnetic resonance imaging (MRI). In an example embodiment, a method includes acquiring undersampled MRI data corresponding to a set of images associated with an area of interest of a subject, and separating an image of the set of images into image regions. The method also includes performing motion tracking for each of the image regions, grouping the motion-tracked image regions into clusters, and applying a sparsity transform to the clusters, to form sparsity-exploited, transformed image regions. The method further includes forming a set of merged images from the plurality of sparsity-exploited, transformed image regions, and updating the set of merged images based on data fidelity, to form an updated set of estimated images.

Abstract: A system and method for providing a dark-blood technique for contrast-enhanced cardiac magnetic resonance, improving visualization of subendocardial infarcts or perfusion abnormalities that may otherwise be difficult to distinguish from the bright blood pool. In one technique the dark-blood preparation is performed using a driven-equilibrium fourier transform (DEFT) preparation with motion sensitizing gradients which attenuate the signal in the ventricular cavities related to incoherent phase losses resulting from non-steady flow within the heart. This dark-blood preparation preserves the underlying contrast characteristics of the pulse sequence causing a myocardial infarction to be bright while rendering the blood pool dark. When applied to perfusion imaging, this dark-blood preparation will help eliminate artifacts resulting from the juxtaposition of a bright ventricular cavity and relatively dark myocardium.

Abstract: Systems and methods for accelerated arterial spin labeling (ASL) using compressed sensing are disclosed. In one aspect, in accordance with one example embodiment, a method includes acquiring magnetic resonance data associated with an area of interest of a subject, wherein the area of interest corresponds to one or more physiological activities of the subject. The method also includes performing image reconstruction using temporally constrained compressed sensing reconstruction on at least a portion of the acquired magnetic resonance data, wherein acquiring the magnetic resonance data includes receiving data associated with ASL of the area of interest of the subject.

Abstract: Myocardial tissue tracking techniques are used to project or guide a single manually-defined set of myocardial contours through time. Displacement encoding with stimulated echoes (DENSE), harmonic phase (HARP) and speckle tracking is used to encode tissue displacement into the phase of complex MRI images, providing a time series of these images, and facilitating the non-invasive study of myocardial kinematics. Epicardial and endocardial contours need to be defined at each frame on cine DENSE images for the quantification of regional displacement and strain as a function of time. The disclosed method presents a novel and effective two dimensional semi-automated segmentation technique that uses the encoded motion to project a manually defined region of interest through time. Contours can then easily be extracted for each cardiac phase.

Abstract: A system and method for providing a dark-blood technique for contrast-enhanced cardiac magnetic resonance, improving visualization of subendocardial infarcts or perfusion abnormalities that may otherwise be difficult to distinguish from the bright blood pool. In one technique the dark-blood preparation is performed using a driven-equilibrium fourier transform (DEFT) preparation with motion sensitizing gradients which attenuate the signal in the ventricular cavities related to incoherent phase losses resulting from non-steady flow within the heart. This dark-blood preparation preserves the underlying contrast characteristics of the pulse sequence causing a myocardial infarction to be bright while rendering the blood pool dark. When applied to perfusion imaging, this dark-blood preparation will help eliminate artifacts resulting from the juxtaposition of a bright ventricular cavity and relatively dark myocardium.

Abstract: A method is disclosed to reconstruct multiphase MR images that accurately depict the entire cardiac cycle. A segmented, echo-planar imaging (EPI) pulse sequence is used to acquire data continuously during each cardiac cycle. Images are retrospectively reconstructed by selecting views from each heartbeat based on cardiac phase.

Abstract: An MRI scan is conducted in which velocity encoded NMR data is acquired for a slice through the heart. Velocity images and magnitude images are reconstructed at multiple cardiac phases and masks are formed using the magnitude images. The masks are applied to the velocity images to isolate the left ventricle, and rigid body motion is calculated and subtracted from the masked velocity images to indicate deformation of the left ventricle.

Abstract: A method is disclosed to reconstruct multiphase MR images that accurately depict the entire cardiac cycle. A segmented, gradient-recalled-echo sequence is modified to acquire data continuously. Images are retrospectively reconstructed by selecting views from each heartbeat based on cardiac phase rather than the time elapsed from the QRS complex. Cardiac phase is calculated using a model that compensates for beat-to-beat heart rate changes.

Abstract: In a magnetic resonance imaging (MRI) system, a method is provided for reducing oblique Nyquist ghost artifact in an image produced by an oblique EPI scan. Prior to commencing the EPI scan, referencing pre-scans are conducted to generate pre-scan echo trains respectively corresponding to the physical gradient axes. Distortion compensating parameters are derived from the pre-scan echo trains for reducing Nyquist ghost by alternatively modifying the data acquisitions stage of the oblique EPI scan, or the post-data acquisition image processing stage thereof. In one mode of operation, the pre-scan echo trains are generated while a subject is in the MRI system. In another mode of operation, pre-scan echo trains are generated while no subject is present in the MR system, so that the distortion compensating parameters represent characteristics of the MR system only, and thus may be used for EPI scans of different protocols.