Mayo Foundation for Medical Education and Research

Michigan State University

Matthew W Urban

James Fowler Greenleaf

Shigao Chen

Armando Manduca

Pengfei Song

Bo Qiang

Heng Zhao

Daniel C Mellema

Joshua D Trzasko

Michael J Yaszemski

Yi Zheng

Carolina Amador Carrascal

Johnathon M Aho

Aiping Yao

Dennis A Wigle

Ivan Z Nenadic

Randall Kinnick

Alireza Nabavizadehrafsanjani

Yiqun Yang

Robert J McGough

Christine U Lee

James L Herrick

Alan L Miller, Ii

James W Jakub

Benjamin G Wood

Nathan J Brinkman

Piotr Kijanka

Margherita Capriotti

Hyungkyi Lee

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.

Non-metallic ultrasound-detectable markers

Systems and methods for Plane Wave Compounding ('PWC') are provided for improving image quality with reduced phase shift errors. The initial phase difference (“IPD”) between two PW transmissions is related to the phase shift error. When the absolute value of IPD is larger than π/2, the phase shift error occurs. An Initial-Phase-Compensated PWC (“IPCPWC”) method may be used to compensate the initial phase of echo signals from each PW transmit and maintain the absolute value of IPD smaller than π/2. IPCPWC methods may also include increased motion signal-to-noise ratio and reduced jitter.

Systems and methods for plane wave compounding in ultrasound imaging

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 PRF, 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.

Time-aligned plane wave compounding of ultrasound data

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.

Phase velocity imaging using an imaging system

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.

Systems and methods for ultrasound elastography with continuous transducer vibration

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.

Shear wave elastography with ultrasound probe oscillation

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.

Shear wave group velocity estimation using spatiotemporal peaks and amplitude thresholding

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.

Systems and methods for assessing properties of biological tubes

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.

Shear viscosity imaging with acoustic radiation force

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.

System and method for model-independent quantification of tissue viscoelastic properties using ultrasound

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.

Systems and methods for efficiently simulating wave propagation in viscoelastic media

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.

System and method for gradient-based k-space search for shear wave velocity dispersion estimation

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.

System and method for shear wave generation with steered ultrasound push beams

The present invention provides a system and method for ultrasound processes using wave attenuation derived from k-space analysis by analyzing spatial frequency domain data.

Shear wave attenuation from k-space analysis system

A system and method for measuring material properties of a medium includes producing a multi-directional wave field in the medium and detecting, with a detection system capable of detecting wave fields propagating in a medium, the multi-directional wave field in at least two spatial dimensions over at least one time instance. The system and method also include determining a lowest wave speed, calculating at least one of wave speed and material properties of the medium, and generating a report indicating the at least one of wave speed and material properties of the medium.

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Rochester, MN, United States of America

Matthew W Urban