Abstract: A method for calculating a mechanical property of a material using a magnetic resonance imaging (“MRI”) system is provided. The method is particularly robust to image data having low signal-to-noise ratio (“SNR”). An MRI system is used to acquire magnetic resonance elastography (“MRE”) data from a subject containing the material. Exemplary materials include lung tissue. Images are reconstructed from the MRE data and used to produce a wave image from which a spatial frequency spectrum is produced. A principal frequency of the spatial frequency spectrum is produced and used to calculate a mechanical property of the material. For example, shear stiffness may be calculated.

Abstract: Methods, systems, and apparatuses for non-convex prior image constrained compressed sensing are disclosed. In one embodiment, a method is provided for iterative image reconstruction for medical imaging applications which employ a prior image to constrain the reconstruction process allowing the use of fewer high SNR samples or complete but lower SNR samples. The objective function made use of non-convex compressed sensing methods during the iterative reconstruction process. Applications include, but are not limited to radiation dose reduction and fast image acquisition.

Abstract: A method for image reconstruction that utilizes the benefits of compressed sensing (“CS”) while incorporating a priori knowledge of object spatial support into the image reconstruction is provided. Image data is acquired from a subject, for example, with a medical imaging system, such as a magnetic resonance imaging (“MRI”) system or a computed tomography (“CT”) system. An estimate of the spatial support of the subject is produced, for example, using a low resolution image of the subject, or an image reconstructed from undersampled image data in a traditional sense. An estimate image of the subject is also produced by using traditional image reconstruction methods on the acquired image data. An image of the subject is then reconstructed using the produced estimate image and produced spatial support estimate. This method allows for the reconstruction of quality images from undersampled image data in a computationally efficient manner.

Abstract: A method for reconstructing an image of a subject from multi-coil data acquired with an array of radio frequency (“RF”) receiver coils that form a part of a magnetic resonance imaging (“MRI”) system without the need for coil sensitivity calibration is provided. A coil data set is acquired for each of the RF receiver coils, for example, by undersampling k-space. A set of image blocks that defines the location and size of each of a plurality of image blocks in the image domain is then selected. The acquired coil data sets and selected image block set are then used to jointly estimate a coil image for each of the plurality of RF receiver coils while promoting locally-low rank structure in the coil images. These coil images are then combined to produce the target image of the subject.

Abstract: The shear stiffness of a subject's spleen is measured using elastography techniques such as ultrasound elastography or a magnetic resonance elastography (MRE) acquisition with an MRI system. A relationship between splenic shear stiffness and portal venous blood pressure is modeled and is used to calculate portal venous blood pressure non-invasively from the measured splenic shear stiffness.

Abstract: Systems, methods and articles of manufacture are disclosed for compensating for motion of a subject during an MRI scan of the subject. k-space data may be received from the MRI scan of the subject. Motion information may be received for the subject. Based on the received motion information, a translational motion of the subject may be determined between a first point in time and a second point in time. A search space for motion correction may be reduced using the determined change and an error margin of the capturing technique. A motion-compensated, graphical image of the subject may be generated using the reduced search space.

Abstract: Methods for measuring mechanical properties of an object or subject under examination with an ultrasound system and using unfocused ultrasound energy are provided. Shear waves that propagate in the object or subject are produced by applying unfocused ultrasound energy to the object or subject, and measurement data is acquired by applying focused or unfocused ultrasound energy to at least one location in the object or subject at which shear waves are present Mechanical properties are then calculated from the acquired measurement data.

Abstract: An improved method for processing image voxel data representative of 3-dimensional images of a colon to remove the effects of tagged stool. The method uses parabolic curve intensity-gradient models at a transition between two material types as a function of the fraction of the two materials for each of a plurality of two-material type classes, including a gas-tissue transition model, a gas-stool transition model and a stool-tissue transition model. The voxels are classified into one of a plurality of substance classes including tagged stool, gas, tissue and unknown classes. The unknown class voxels are processed to classify the unknown class voxels into one of the two-material type classes. The two-material type class voxels are processed to determine the fractions of materials in each voxel. The intensity of the two-material type class voxels is then adjusted as a function of the fraction of the materials in the voxels.

Abstract: A system and method for reconstructing an image acquired by delivering an irradiating dose of radiation to a subject includes acquiring imaging data using a dose of irradiating radiation and selecting at least one of a plurality of mechanisms for reducing the dose that could be delivered to the subject to acquire additional imaging data. Noise is inserted into the imaging data to simulate the at least one of the plurality of mechanisms for reducing the dose that could be applied to acquire the additional imaging data to thereby generate simulated imaging data at a reduced dose of irradiating radiation. A simulated reduced dose image is reconstructed from the simulated imaging data. A method is provided for utilizing a non-local means filter adapted using a map of local noise to produce denoised medical imaging data reflecting reduced local nose levels from those in originally-acquired medical imaging data.

Abstract: A system and method is provided for estimating the local noise of CT images and denoising the images using a modified non-local means (NLM) algorithm that is adaptive to local variations of noise levels. A strategy for efficiently estimating the local noise of CT images is also described.

Abstract: Systems, methods and articles of manufacture are disclosed for capturing motion information in a magnetic resonance imaging (MRI) environment. A light sink in the MRI environment may detect light emitted from a plurality of light sources. Each of the plurality of light sources may emit light of a different frequency. Further, each of the plurality of light sources may be located at a different spatial position in the MRI environment. The detected light may be analyzed. A change in spatial position of the light sink may be computed based on the analysis.

Abstract: A method for reconstructing a time series of images from data acquired with a medical imaging system is provided. Data is acquired with the medical imaging system, and a set of image blocks that defines the location and size of each of a plurality of image blocks in the image domain is then selected. The acquired data and selected image block set are then used to jointly estimate a plurality of images that form a time series of images while promoting locally-low rank structure in the images.

Abstract: A system and method for analyzing a subject using a magnetic resonance imaging (MRI) system is provided. The technique includes positioning a subject within the MRI system and coupling a driver to the subject to impart vibrational energy to the subject. The technique further includes using the MRI system and in coordination with operation of the driver, acquiring medical imaging data from the subject's brain and deriving stiffness information of the subject's brain from the medical imaging data. A report, such as an image, can be provided indicating the stiffness information of the subject's brain relative to baseline stiffness information to indicate a status of the subject with respect to a neurodegenerative disease.

Abstract: A method for processing and displaying colonography image data. First distance tissue pixels representative of tissue within a first distance of gas pixels representative of gas are processed with a first window/level setting to generate a first setting set of image pixels. Second distance tissue pixels representative of tissue within a second distance of the gas pixels are processed with a second window/level setting to generate a second setting set of image pixels. The second distance is a distance greater than the first distance. A colonography image including both the first and second setting sets of image pixels is then displayed.

Abstract: Systems, methods and articles of manufacture are disclosed for compensating for motion of a subject during an MRI scan of the subject. k-space data may be received from the MRI scan of the subject. A first graphical image may be generated from a first set of data elements from the k-space data. Similarly, a second graphical image may be generated from a second set of data elements from the k-space data. An offset in pixels may be determined by which to translate the second graphical image from the first graphical image to compensate for the motion. The k-space data may be modified at a sub-pixel offset relative to the determined offset. A motion-compensated graphical image of the subject may be generated from the modified k-space data. Doing so reduces the search space evaluated to sharpen images generated from the k-space data.

Abstract: A method for image reconstruction that utilizes a generalization of compressed sensing is provided. More particularly, a method for homotopic l0 minimization is provided, in which a series of subproblems that asymptotically approach a solution to the l0 minimization are iteratively solved. These subproblems include utilizing concave metric prior functionals in the traditional compressed sensing framework. Substantially undersampled image data is acquired from a subject, for example, with a medical imaging system, such as a magnetic resonance imaging (“MRI”) system or a computed tomography (“CT”) system. Using the provided method, undersampling on the order of around 96 percent can be achieved while still producing clinically acceptable images.

Abstract: A method for calculating a mechanical property of a material using a magnetic resonance imaging (“MRI”) system is provided. The method is particularly robust to image data having low signal-to-noise ratio (“SNR”). An MRI system is used to acquire magnetic resonance elastography (“MRE”) data from a subject containing the material. Exemplary materials include lung tissue. Images are reconstructed from the MRE data and used to produce a wave image from which a spatial frequency spectrum is produced. A principal frequency of the spatial frequency spectrum is produced and used to calculate a mechanical property of the material. For example, shear stiffness may be calculated.

Abstract: Methods, systems, and apparatuses for non-convex prior image constrained compressed sensing are disclosed. In one embodiment, a method is provided for iterative image reconstruction for medical imaging applications which employ a prior image to constrain the reconstruction process allowing the use of fewer high SNR samples or complete but lower SNR samples. The objective function made use of non-convex compressed sensing methods during the iterative reconstruction process. Applications include, but are not limited to radiation dose reduction and fast image acquisition.

Abstract: A method for processing and displaying colonography image data. First distance tissue pixels representative of tissue within a first distance of gas pixels representative of gas are processed with a first window/level setting to generate a first setting set of image pixels. Second distance tissue pixels representative of tissue within a second distance of the gas pixels are processed with a second window/level setting to generate a second setting set of image pixels. The second distance is a distance greater than the first distance. A colonography image including both the first and second setting sets of image pixels is then displayed.

Abstract: Projection data acquired with an x-ray CT system is filtered using a bilateral filter to reduce image noise and enable the acquisition at lower x-ray dose without the loss of image diagnostic quality. The bilateral filtering is performed before image reconstruction by producing a noise equivalent data set from the acquired projection data and then converting the bilateral filtered values back to a projection data set suitable for image reconstruction.