Shear wave phase velocity estimation with extended bandwidth using generalized Stockwell transform and slant frequency wavenumber analysis
AssigneesMayo Foundation for Medical Education and Research, Akademia Gorniczo-Hutnicza Im. Stanislawa Stanszica W Krakowie
InventorsPiotr Kijanka, Matthew W. Urban
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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.
Claims22
A method for generating shear wave phase velocity data from ultrasound data obtained with an ultrasound system, the method comprising:
- (a) accessing ultrasound data with a computer system, the ultrasound data being representative of shear wave motion in a region-of-interest in a subject;
- (b) generating time-frequency-space domain data with the computer system by applying a Stockwell transform to the ultrasound data, wherein the Stockwell transform is a generalized Stockwell transform that implements a generalized window function, wherein the generalized window function includes a scaling factor that changes a width of the generalized window function and controls time-frequency resolution by altering a number of oscillations in the generalized window function;
- (c) generating a slant-phase function from the time-frequency-space domain data using the computer system;
- (d) computing slant-phase amplitude values with the computer system using the slant-phase function;
- (e) generating phase velocity dispersion curve data from the slant-phase amplitude values using the computer system, wherein the phase velocity dispersion curve data is generated over an extended frequency bandwidth that enables differentiation between soft tissues in the region-of-interest in the subject;
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- (f) displaying the phase velocity dispersion curve data as a phase velocity map on a display system, wherein the phase velocity map depicts a spatial distribution of measured shear wave phase velocity values within the region-of-interest.
A method for generating shear wave phase velocity data from elastography data obtained with an imaging system, the method comprising:
- (a) accessing elastography data with a computer system, the elastography data being representative of shear wave motion in a region-of-interest in a subject;
- (b) generating time-frequency-space domain data with the computer system by applying a Stockwell transform to the elastography data, wherein the Stockwell transform is a generalized Stockwell transform that implements a generalized window function, wherein the generalized window function includes a scaling factor that changes a width of the generalized window function and controls time-frequency resolution by altering a number of oscillations in the generalized window function;
- (c) generating a slant-phase function from the time-frequency-space domain data using the computer system;
- (d) computing slant-phase amplitude values with the computer system using the slant-phase function;
- (e) generating phase velocity dispersion curve data from the slant-phase amplitude values using the computer system, wherein the phase velocity dispersion curve data is generated over an extended frequency bandwidth that enables differentiation between soft tissues in the region-of-interest in the subject;
- (f) generating mechanical property data from the phase velocity dispersion curve data;
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- (g) displaying the mechanical property data as a mechanical property map on a display system, wherein the mechanical property map depicts a spatial distribution of viscoelastic property values in the region-of-interest.
Dependencies are inferred from the claim text.