Sparse tracking in acoustic radiation force impulse imaging

• US 20160199034A1
• Filed: 01/12/2015
• Published: 07/14/2016
• Est. Priority Date: 01/12/2015
• Status: Active Grant

• Current Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Labyed, Yassin, Kim, Seungsoo, Duncan, David P., Hsu, Stephen J., Fan, Liexiang
• Granted Patent: US 9,907,539 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 8/461 Displaying means of special interest
• CPC Class Codes: A61B 8/485 involving measuring strain or elastic properties
• CPC Class Codes: A61B 8/5207 involving processing of raw data to produce diagnostic data, e.g. for generating an image reconstruction G06T11/00
• CPC Class Codes: A61B 8/5215 involving processing of medical diagnostic data
• CPC Class Codes: G01S 15/8977 using special techniques for image reconstruction, e.g. FFT, geometrical transformations, spatial deconvolution, time deconvolution
• CPC Class Codes: G01S 7/52022 using a sequence of pulses, at least one pulse manipulating the transmissivity or reflexivity of the medium
• CPC Class Codes: G01S 7/52042 determining elastic properties of the propagation medium or of the reflective target diagnostic techniques involving the measurement of strain A61B8/485
• CPC Class Codes: G01S 7/52071 Multicolour displays; using colour coding; Optimising colour or information content in displays, e.g. parametric imaging
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

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.

Claims

1. A method for sparse tracking in acoustic radiation force impulse imaging, the method comprising:

transmitting, with an ultrasound scanner, an acoustic radiation force impulse into tissue of a patient along a first line;

tracking, with the ultrasound scanner, a wave generated in response to the transmitting with four or fewer receive beams along each of a plurality of tracking lines spaced from the first line;

determining a displacement for each of the tracking lines, the displacements comprising a sparse displacement sampling of the tracking lines;

performing compressive sensing of the sparse displacement sampling;

inverse Fourier transforming results of the compressive sensing;

Radon transforming results of the inverse Fourier transforming;

calculating a velocity of the wave from results of the Radon transforming; and

generating an image of the velocity.

2. The method of claim 1 wherein transmitting comprises transmitting the acoustic radiation force impulse as focused at a depth along the first line, and wherein tracking comprises tracking the wave at the depth on the tracking lines, the wave comprising a shear wave.

3. The method of claim 1 wherein tracking comprises tracking with the receive beams being randomly distributed in time along the tracking lines.

4. The method of claim 3 wherein the random distribution is within a cone of tracking line as a function of the time, the cone defining a range of possible positions as a function of the time for the wave given the tissue.

5. The method of claim 1 wherein tracking comprises tracking over N of the tracking lines where N is a multiple of two or more of a number of simultaneous receive beam capability of the ultrasound scanner.

6. The method of claim 1 wherein determining comprises determining an amount of shift of tissue from a reference.

7. The method of claim 1 wherein tracking comprises tracking with simultaneous parallel receive beamforming with N simultaneous receive beams per receive event, and wherein determining comprises determining the displacements with one displacement per receive beam and N displacements per receive event.

8. The method of claim 1 wherein determining comprises determining magnitudes of the displacements without specific identification of a maximum displacement at any of the tracking lines.

9. The method of claim 1 wherein performing the compressive sensing comprises performing an orthogonal matching pursuit.

10. The method of claim 1 wherein calculating the velocity comprises identifying an angle of tracking line as a function of time.

11. The method of claim 1 wherein tracking comprises tracking with the tracking lines distributed in azimuth and elevation positions relative to a transducer of the ultrasound scanner, and wherein the velocity for a depth is calculated as a function of the sparse displacement sampling of the azimuth and elevation positions of the tracking lines.

12. In a non-transitory computer readable storage medium having stored therein data representing instructions executable by a programmed processor for sparse tracking in acoustic radiation force impulse imaging, the storage medium comprising instructions for:

measuring, using an ultrasound scanner, displacements in response to a single excitation pulse, the displacements measured at random locations over time;

determining a velocity of a wave generated by the single excitation pulse from the displacements; and

outputting the velocity.

13. The non-transitory computer readable storage medium of claim 12 wherein measuring comprises measuring N displacements per receive event for N tracking lines, respectively, and repeating the measuring for other groups of N of the tracking lines.

14. The non-transitory computer readable storage medium of claim 13 wherein the random locations are within a limiting region of the tracking lines and time from the excitation pulse.

15. The non-transitory computer readable storage medium of claim 12 wherein the ultrasound scanner is operable to receive beamform only N receive beams simultaneously, and wherein measuring comprises measuring for N receive lines at a time with XN receive lines measured in response to the single excitation pulse where X is two or more such that displacements are not measured for at least some of the receive lines more than once.

16. The non-transitory computer readable storage medium of claim 12 wherein determining the velocity comprises compressively sensing from the displacements, inverse Fourier transforming an output of the compressively sensing, Radon transforming an output of the inverse Fourier transforming, and calculating the velocity from an output of the Radon transforming.

17. The non-transitory computer readable storage medium of claim 12 wherein outputting comprises displaying a value of the velocity for a user selected location.

18. A system for sparse tracking in acoustic radiation force impulse imaging, the system comprising:

a transmit beamformer configured to generate a excitation pulse;

a receive beamformer configured to sparsely track displacements responsive to the excitation pulse, the sparsely tracked displacements distributed by receive line over sample time such that no displacements are provided for more than half of the times for each of the receive lines;

a processor configured to estimate velocity from the sparsely tracked displacements; and

a display operable to display the velocity.

19. The system of claim 18 wherein the receive beamformer is operable to simultaneously receive beamform along N receive lines where N is an integer greater than one, the receive beamformer configured to measure N of the displacements at each of the sample times with the receive lines for the displacements being randomly positioned over XN of the receive lines, where X is two or greater, and wherein the processor is configured to estimate the velocity in response to only the excitation pulse.

20. The system of claim 18 wherein the processor is configured to estimate the velocity with compressive sensing.

21. The system of claim 18 wherein the receive beamformer is configured to sparsely track in three dimensions.