Abstract: Shear wave phase velocity is estimated from measurements of shear wave motion obtained using ultrasound shear wave elastography or other suitable elastography techniques. Shear wave dispersion curves are generated using a combined generalized Stockwell transform and slant wave number-frequency analysis. A modified version of the S-transform is used to control the time-frequency resolution of a time-frequency decomposition of a signal.

Abstract: Shear wave elastography and/or other ultrasound imaging procedures are performed using a data acquisition technique in which data are acquired with high SNR while maintaining a high PRFe, using conventional clinical ultrasound scanners. In general, ultrasound data are acquired using plane waves at different angles, after which a time alignment process is applied to the acquired data. The time alignment uses interpolation to obtain data points at higher frame rates, and the time-aligned data is compounded to increase the SNR.

Abstract: Methods for processing data acquired using ultrasound elastography, in which shear waves are generated in a subject using continuous vibration of the ultrasound transducer, are described. The described methods can effectively separate shear wave signals from signals corresponding to residual motion artifacts associated with vibration of the ultrasound transducer. The systems and methods described here also provide for real-time visualization of shear waves propagating in the subject.

Abstract: Markers (e.g., treatment site markers, biopsy site markers) are composed of a non-metallic material having a composition and/or other features or characteristics such that the markers will generate twinkling artifacts when imaged with ultrasound. In this way, the composition of the markers enables their detection and localization using ultrasound. The markers are generally composed of non-metallic materials that enhance the twinkling artifact.

Abstract: Described here are systems and methods for estimating shear wave velocity from data acquired with a shear wave elastography system. More particularly, the systems and methods described here implement a spatiotemporal time-to-peak algorithm that searches for the times at which shear wave motion is at a maximum while also searching for the lateral locations at which shear wave motion is at a maximum. Motion can include displacement, velocity, or acceleration caused by propagating shear waves. A fitting procedure (e.g., a linear fit) is performed on a combined set of these temporal peaks and spatial peaks to estimate the shear wave velocity, from which mechanical properties can be computed. Motion amplitude thresholding can also be used to increase the number of points for the fitting.

Abstract: Markers, medical instruments, and/or medical devices have a composition and/or other features or characteristics such that they will generate twinkling artifacts when imaged with ultrasound. In this way, the markers, medical instruments, and/or medical devices can be detected and localized using ultrasound. Ultrasound technical specifications that are optimized to generate twinkling artifact signatures are selected and used to facilitate localization of such markers, instruments, and/or devices.

Abstract: Methods for processing data acquired using ultrasound elastography, in which shear waves are generated in a subject using continuous vibration of the ultrasound transducer, are described. The described methods can effectively separate shear wave signals from signals corresponding to residual motion artifacts associated with vibration of the ultrasound transducer. The systems and methods described here also provide for real-time visualization of shear waves propagating in the subject.

Abstract: Described here are systems and methods for phase velocity imaging using an imaging system, such as an ultrasound system, an optical imaging system (e.g., an optical coherence tomography system), or a magnetic resonance imaging system. In general, systems and methods for constructing phase velocity images (e.g., 2D images, 3D images) from propagating mechanical wave motion data are described. The systems and methods described in the present disclosure operate in the frequency domain and can be implemented using a single frequency or a band of selected frequencies. If there are multiple mechanical wave sources within the field-of-view, directional filtering may be performed to separate mechanical waves propagating in different directions. The reconstructions described below can be performed for each of these directionally filtered components.

Abstract: A system and method is provided for measuring a mechanical property of a biological tube. The system and method operate to arrange a plurality of piezoelectric elements about the biological tube and apply a predetermined force or transduce an endogeneous or exogeneous force to the biological tube. The system and method also operate to receive a respective signal from each piezoelectric element in the plurality of piezoelectric elements responsive to the application of the predetermined force or a transduced endogenous or exogeneous force and calculate the mechanical property of the biological tube based on the signals received from the plurality of piezoelectric elements.

Abstract: Methods for estimating the phase velocity of a shear wave from ultrasound data are described. An ultrasound system is used to measure one or more shear waves propagating in a region-of-interest in a subject, and from this data the phase velocity of the one or more shear waves can be estimated. In general, the phase velocity is estimated from a wavenumber spectrum computed from temporal frequency data generated by Fourier transforming the ultrasound data along one or more temporal dimensions. A multiple signal classification (i.e., MUSIC) technique is adapted to separate the temporal frequency data into signal and noise subspaces, from which wavenumber spectra can be estimated based, at least in part, on an estimation function.

Abstract: Shear waves are generated and measured in viscoelastic phantoms by a single push beam. Using numerical simulations or an analytical function to describe the diffraction of the shear wave, the resulting shear wave motion induced by the applied push beam is calculated with different shear elasticity values and then convolved with a separate expression that describes the effects of viscosity value for the medium. The optimization algorithm chooses the tissue parameters which provide the smallest difference between the measured shear waveform and the simulated shear waveform. A shear viscosity image is generated by applying such optimization procedure at all of the observation points.

Abstract: A model-independent method for producing a viscoelastic tissue property metric using ultrasound is provided. A mechanical stress, such as an acoustic force, is applied to a tissue using an ultrasound system and tissue displacement resulting from the applied acoustic force is measured. From the tissue displacement measurements, a complex modulus, such as a relative complex modulus, is extracted. A loss tangent is calculated from the extracted complex modulus. Using the calculated loss tangent, viscoelastic tissue property metrics may be calculated.

Abstract: Described here are systems and methods for estimating shear wave velocity from data acquired with a shear wave elastography system. More particularly, the systems and methods described here implement a spatiotemporal time-to-peak algorithm that searches for the times at which shear wave motion is at a maximum while also searching for the lateral locations at which shear wave motion is at a maximum. Motion can include displacement, velocity, or acceleration caused by propagating shear waves. A fitting procedure (e.g., a linear fit) is performed on a combined set of these temporal peaks and spatial peaks to estimate the shear wave velocity, from which mechanical properties can be computed. Motion amplitude thresholding can also be used to increase the number of points for the fitting.

Abstract: Systems and methods for processing data acquired using ultrasound elastography, in which shear waves are generated in a subject using continuous vibration of an ultrasound transducer, are provided. The systems and methods described here can effectively remove motion artifacts associated with vibration of the ultrasound transducer, and can also remove the data sampling misalignment caused when a line-by-line imaging mode is used to acquire data, as is done by many conventional ultrasound scanners. Thus, the systems and methods described here provide techniques for transducer motion correction and for aligning motion signals detected by line-by-line scanning ultrasound systems.

Abstract: Described here are systems and methods for efficiently simulating wave propagation in one or more viscoelastic media. The systems and methods described here implement an elastodynamic model that includes memory variables for one or more viscoelastic properties. Boundary conditions can also be generated based on a perfectly matched layer (PML) condition. A hybrid implicit/explicit method is used to generate wave simulation data. In this method, equations related to the memory variables and PML are solved using an implicit integrator, and other equations in the elastodynamic model are solved using an explicit method.

Abstract: Shear waves are generated and measured in viscoelastic phantoms by a single push beam. Using numerical simulations or an analytical function to describe the diffraction of the shear wave, the resulting shear wave motion induced by the applied push beam is calculated with different shear elasticity values and then convolved with a separate expression that describes the effects of viscosity value for the medium. The optimization algorithm chooses the tissue parameters which provide the smallest difference between the measured shear waveform and the simulated shear waveform. A shear viscosity image is generated by applying such optimization procedure at all of the observation points.

Abstract: Described here are systems and methods for ultrasound processes using shear wave attenuation and velocity derived from k-space analysis by analyzing spatial frequency domain data.

Abstract: A system and method for performing a steered push beam (SPB) technique to create multiple foci generated by the interference of different ultrasound push beams to create shear waves and, based thereon, generate a report indicating mechanical properties about an object.

Abstract: A system and method is provided for measuring a mechanical property of a biological tube. The system and method operate to arrange a plurality of piezoelectric elements about the biological tube and apply a predetermined force or transduce an endogeneous or exogeneous force to the biological tube. The system and method also operate to receive a respective signal from each piezoelectric element in the plurality of piezoelectric elements responsive to the application of the predetermined force or a transduced endogenous or exogeneous force and calculate the mechanical property of the biological tube based on the signals received from the plurality of piezoelectric elements.

Abstract: Systems and methods are provided for measuring and isolating circumferential wave speed within a vessel wall of a substantially cylindrical vessel. The methods include measuring a motion at a first location and a second location opposite the first location and isolating the circumferential wave speed. The methods also include generating a report using the longitudinal or circumferential wave speeds.