Siemens Medical Solutions Usa, Inc.

Liexiang Fan

Yassin Labyed

Paul Donald Freiburger

Seungsoo Kim

Kevin Michael Sekins

Patrick Von Behren

David P Duncan

John Benson

Nikolas Ivancevich

Stephen J Hsu

King Yuen Wong

Stephen J Rosenzweig

Wayne J Gueck

Roee Lazebnik

Caroline Maleke

Richard Chiao

Dorin Comaniciu

Ali Kamen

Tommaso Mansi

Thilaka S Sumanaweera

Saikiran Rapaka

Patrick Gross

John I Jackson

Helene C Houle

Arun Palligaranai Tirumalai

Mervin Mencias Smith-Casem

Andrzej Milkowski

Zuhua Mao

David E Gustafson

Chi-Yin Lee

Xiaozheng Zeng

Carol Lowery

Manoj G Menon

Thomas Edward Cezeaux

Francois Forlot

Art Schenck

Matthew Holladay

Greg Sherwin

Nikolas M Ivancevich

Motion independent acoustic radiation force impulse imaging is provided. Rather than rely on the displacement over time for each location, the displacements over locations for each time are used. Parallel beamforming is used to simultaneously sample across a region of interest. Since it may be assumed that the different locations are subjected to the same motion at the same time, finding a peak displacement over locations for each given time provides peak or profile information independent of the motion. The velocity or other viscoelastic parameter may be estimated from the displacements over locations.

Motion independence in acoustic radiation force impulse imaging

Shear wave propagation is used to estimate the speed of sound in a patient. An ultrasound scanner detects a time of occurrence of a shear wave at each of multiple locations. The difference in time of occurrence, given tissue stiffness or shear velocity, is used to estimate the speed of sound for the specific tissue of the patient.

Sound speed imaging using shear waves

Fat fraction is estimated from shear wave propagation. Acoustic radiation force is used to generate a shear wave in tissue of interest. The attenuation, center frequency, bandwidth or other non-velocity characteristic of the shear wave is calculated and used to estimate the fat fraction.

Fat fraction estimation using ultrasound with shear wave propagation

For noise reduction in elasticity imaging, frequency compounding is used. Displacements caused by the acoustic radiation force impulse are measured using signals at different frequencies, either due to transmission of tracking pulses and reception at different frequencies or due to processing received signals at different sub-bands. The displacements are (a) combined to compound and the compounded displacements are used to determine elasticity or (b) are used to determine elasticity and the elasticities from information at the different frequencies are compounded.

Frequency compounding in elasticity imaging

To increase the signal-to-noise ratio for displacements used to estimate the shear speed in patient tissue, constructive interference from multiple shear waves is used. By transmitting acoustic radiation force impulses focused at different locations, the resulting shear waves may constructively interfere within a region of interest. This constructive interference causes a greater amplitude of displacement. The location of this more easily detected greater interference and the difference in time of the transmitted acoustic radiation force impulses are used to estimate the shear wave speed for the tissue.

Sheer speed imaging using coherence

For acoustic radiation force ultrasound imaging, multiple displacement profiles for a given location are acquired. Physiological and/or transducer axial and/or lateral motion are accounted for using the displacements from the different acoustic radiation force impulses. For axial motion, a difference between the displacements of the different profiles provides information about motion during displacement at the location caused by just the undesired motion. A more accurate estimate of the undesired motion for removing from the displacement profile is provided. For lateral motion, the displacement profiles are obtained using waves traveling from different directions relative to the given location. An average of velocities estimated from the different profiles removes undesired lateral motion.

Adaptive motion estimation in acoustic radiation force imaging

Shear wave characteristics are estimated from analytic data. Measures of displacement are converted into complex representations. The magnitude and/or phase components of the complex representation may be used for estimating various characteristics, such as velocity, center frequency, attenuation, shear modulus, or shear viscosity. The zero-phase of the phase component represents an occurrence of the shear wave at that location.

Shear wave estimation from analytic data

For estimating attenuation in ultrasound imaging, displacements at different locations along an acoustic radiation force impulse (ARFI) beam are used measured. The on-axis displacements and displacements from a phantom using a same ARFI focus as a reference are used to cancel out focusing effects. A single ARFI beam may be used to estimate the attenuation for a location.

Tissue characterization in medical diagnostic ultrasound

Three-dimensional elasticity imaging is provided. Motion in three-dimensions due to sources other than the stress or compression for elasticity imaging is found from anatomical information. Objects less likely to be subject to the stress or compression and/or likely to be subject to undesired motion are used to find the undesired motion. This anatomical motion is accounted for in estimating the elasticity, such as removing the motion from echo data used to estimate elasticity or subtracting out the motion from motion generated as part of estimating elasticity.

Motion correction in three-dimensional elasticity ultrasound imaging

In viscoelastic imaging with ultrasound, the shear wave speed or other viscoelastic parameter is measured by tracking at the ARFI focal or other high-intensity location relative to the ARFI transmission. Rather than tracking the shear wave, the tissue response to ARFI is measured. A profile of displacements over time or a spectrum thereof is measured at the location. By finding a scale of the profile resulting in sufficient correlation with a calibration profile, the shear wave speed or other viscoelastic parameter may be estimated.

Diffraction source compensation in medical diagnostic ultrasound viscoelastic imaging

Viscosity is included in the quantification by an ultrasound imaging system. The log of a spectrum of displacement as a function of time is determined for each of various locations subjected to a shear or other wave. Solving using the log as a function of location provides the complex wavenumber. Various viscoelastic parameters, such as loss modulus and storage modulus, are determined from the complex wavenumber.

Quantitative viscoelastic ultrasound imaging

Classification preprocessing is provided for medical ultrasound shear wave imaging. In response to stress, the displacement at one or more locations in a patient is measured. The displacement over time is a curve representing a shift in location. One or more characteristics of the curve, such as signal-to-noise ratio and maximum displacement, are used to classify the location. The location is classified as fluid or fluid tissue, solid tissue, or non-determinative. Subsequent shear imaging may provide shear information for locations of solid tissue and not at other locations.

Classification preprocessing in medical ultrasound shear wave imaging

Shear waves are detected with ultrasound. The detection of the shear wave is constrained using prior measurements in a more controlled environment (e.g., less noise). For example, shear waves measured in a phantom are used to constrain the detection of shear waves in a patient to avoid false positive detections.

Shear wave detection in medical ultrasound imaging

Sparse tracking is used in acoustic radiation force impulse imaging. The tracking is performed sparsely. The displacements are measured only one or a few times for each receive line. While this may result in insufficient information to determine the displacement phase shift and/or maximum displacement over time, the resulting displacement samples for different receive lines as a function of time may be used together to estimate the velocity, such as with a Radon transform. The estimation may be less susceptible to noise from the scarcity of displacement samples by using compressive sensing.

Sparse tracking in acoustic radiation force impulse imaging

Tissue density is quantified using shear wave information in medical ultrasound scanning. Measurements of the tissue reaction to shear waves indicate tissue density. For example, shear wave velocity is linked with density using clinical study information. The shear wave velocity in a region, over the entire tissue, or at various locations is used to determine a corresponding density or densities. The tissue density information is used for categorization, estimation of disease risk, imaging, diagnosis, or other uses. The tissue may be breast tissue or other tissue.

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Sammamish, WA, United States of America

Liexiang Fan