Dual process ultrasound contrast agent imaging

• US 6,632,177 B1
• Filed: 05/01/2002
• Issued: 10/14/2003
• Est. Priority Date: 05/01/2002
• Status: Expired due to Term

• Current Assignee: Acuson Corporation (Siemens AG)
• Original Assignee: Acuson Corporation (Siemens AG)
• Inventors: Phillips, Patrick J., Guracar, Ismayil M.
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): Jain, Ruby
• Application Number:
  US10/136,935
• Time in Patent Office: 531 Days
• Field of Search: 600/458, 600/437, 600/442, 600/447, 600/440, 600/441, 600/443, 600/439, 736/25, 736/26, 736/02
• US Class Current: 600/458
• CPC Class Codes: A61B 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039
• CPC Class Codes: G01S 7/52038 involving non-linear properties of the propagation medium or of the reflective target
• CPC Class Codes: G01S 7/52041 detecting modification of a contrast enhancer, e.g. detecting the destruction of a contrast agent by an acoustic wave, e.g. loss of correlation diagnostic techniques involving the use of contrast agents A61B8/481

Abstract

Methods and systems for detecting contrast agents is provided. Differences between different sized vessels throughout a period of contrast agent enhancement are identified without significantly depleting the available contrast agent. Dual detection paths are used for imaging, such as one path for detecting nonlinear response and another path for detecting differences between the responses to two or more pulses. Where echoes from two or more pulses of acoustic energy are combined to detect the nonlinear response, the nonlinear response may also include signals originating from a loss-of-correlation (LOC) or motion between received pulses. These signals generated from LOC or motion can be produced from agent disruption where a second received echo is different from a first received echo due to a change in a bubble'"'"'s shape (i.e., destruction), or from simple spatial translation between acoustic pulses as seen from the same spatial location, respectively. Together the LOC or motion signals and the nonlinear signals can differentiate contrast agent from tissue. Additional information is gained by detecting signals more responsive to difference or motion information. Each path detects different relative amounts of nonlinear response and responses caused by differences between echo signals of multiple pulses. Various systems and methods for detecting contrast agents where one path preferentially detects difference or motion signals and another path preferentially detects nonlinear energy are provided.

Claims

1. A method for detecting contrast agents with ultrasound energy, the method comprising the acts of:

(a) detecting motion or loss-of-correlation between first and second pulses in response to multiple pulses having substantially a same phase and amplitude; and

(b) detecting nonlinear response in response to third and fourth inter-pulse amplitude modulated pulses;

wherein (a) and (b) are performed within 500 milliseconds.

2. The method of claim 1 wherein (a) comprises detecting moving targets while rejecting stationary targets in response to the multiple pulses.

3. The method of claim 1 wherein (b) comprises detecting in response to the third and fourth amplitude modulated pulses, the third and fourth amplitude modulated pulses having different phases.

4. The method of claim 1 further comprising:

(c) transmitting the first and second pulses of (a) at a first low power level; and

(d) transmitting the third and fourth amplitude modulated pulses of (b) at a second low power level;

wherein the first and second power levels comprise one of same and different power levels, the same and different power levels associated with maintaining contrast agents free of substantial destruction.

5. The method of claim 1 further comprising:

(c) transmitting the first and second pulses and a fifth pulse of (a) with peak amplitudes [1 1 1]; and

(d) weighting first, second and third receive echo signals responsive to the first, second and fifth pulses of (a) with first, second and third weights, respectively, corresponding to relative amplitudes and phases of [1 −

2 1].

6. The method of claim 1 further comprising:

(c) transmitting reverberation suppression pulses.

7. The method of claim 1 further comprising:

(c) varying an order of one of multiple receive amplitudes, multiple receive phases, multiple transmit amplitudes, multiple transmit phases and combinations thereof as a function of scan line.

8. The method of claim 1 further comprising:

(c) transmitting the first and second pulses of (a); and

(d) transmitting the third and fourth amplitude modulated pulses of (b) wherein the second and third pulses comprise the same pulse and the first and fourth pulses comprise different pulses.

9. The method of claim 1 further comprising:

(c) comparing detected motion or loss-of-correlation responsive to (a) with a threshold;

(d) selecting the detected motion or loss-of-correlation if the detected motion or loss-of-correlation is above the threshold; and

(e) selecting detected nonlinear response of (b) if the detected motion or loss-of-correlation is below the threshold.

10. The method of claim 1 further comprising:

(c) selecting one of the difference and the nonlinear response for display at a spatial location.

11. The method of claim 1 further comprising:

(c) combining the motion or loss-of-correlation and the non-linear response.

12. The method of claim 1 further comprising:

(c) generating an image responsive to both the motion or loss-of-correlation and the nonlinear response.

13. The method of claim 12 wherein (c) comprises generating an image responsive to the difference, the nonlinear response and a B-mode intensity.

14. The method of claim 1 further comprising:

(c) comparing the motion or loss-of-correlation with a threshold;

(d) outputting a set value if the motion or loss-of-correlation is above the threshold; and

(e) selecting the nonlinear response if the detected motion or loss-of-correlation is below the threshold.

15. A system for detecting contrast agents with ultrasound energy, the system comprising:

a first detector for detecting motion or loss-of-correlation between first and second pulses in response to multiple pulses having substantially a same phase and amplitude; and

a second detector for detecting nonlinear response in response to third and fourth amplitude modulated pulses;

wherein the first and second detectors are operable to detect within 500 milliseconds.

16. The system of claim 15 further comprising:

a transmit beamformer operable to transmit at a first low power level the first and second pulses and to transmit the third and fourth amplitude modulated pulses at a second low power level;

wherein the first and second power levels comprise one of a same power level and different power levels, the same and different power levels associated with maintaining contrast agents free of substantial destruction.

17. The system of claim 15 further comprising:

a processor operable to compare detected motion or loss-of-correlation output from the first detector with a threshold and select the detected motion or loss-of-correlation if the detected motion or loss-of-correlation is above the threshold, but select detected nonlinear response output from the second detector if the detected motion or loss-of-correlation is below the threshold.

18. A method for detecting contrast agents with ultrasound energy, the method comprising the acts of:

(a) detecting motion or a loss-of-correlation between first and second pulses in response to multiple pulses having substantially a same phase and amplitude; and

(b) detecting nonlinear energy in response at least three pulses, a first one of the at least three pulses having a different phase than a second one of the at least three pulses;

wherein (a) and (b) are performed within 500 milliseconds.

19. The method of claim 18 wherein (b) comprises detecting nonlinear response in response to amplitude modulated pulses.

20. The method of claim 18 further comprising:

(c) transmitting the first and second pulses and a fifth pulse of (a) with peak amplitudes [1 1 1]; and

(d) weighting first, second and third receive echo signals responsive to the first, second and fifth pulses of (a) with first, second and third weights, respectively, corresponding to relative amplitudes and phases of [1 −

2 1].

21. The method of claim 18 further comprising:

(c) comparing detected motion or loss-of-correlation responsive to (a) with a threshold;

(d) selecting the detected motion or loss-of-correlation if the detected motion or loss-of-correlation is above the threshold; and

(e) selecting detected nonlinear response of (b) if the detected motion or loss-of-correlation is below the threshold.

22. The method of claim 18 wherein (a) comprises detecting moving targets while rejecting stationary targets.

23. The method of claim 18 wherein (a) comprises detecting a loss-of-correlation.

24. The method of claim 18 wherein (a) comprises transmitting the first and second pulses at a first low power level, and (b) comprises transmitting the at least three pulses at a second low power level;

wherein the first and second power levels comprise one of a same power level and different power levels, the same and different power levels both associated with maintaining contrast agents free of substantial destruction.

25. The method of claim 18 further comprising:

(c) transmitting reverberation suppression pulses.

26. The method of claim 18 further comprising:

(c) varying an order of one of multiple receive amplitudes, multiple receive phases, multiple transmit amplitudes, multiple transmit phases and combinations thereof as a function of scan line.

27. The method of claim 18 wherein the second pulse of (a) comprises one of the at least three pulses of (b) and the first pulse of (a) is not included as any of the at least three pulses of (b).

28. A system for detecting contrast agents with ultrasound energy, the system comprising:

a first detector for detecting motion or a loss-of-correlation between first and second pulses in response to multiple pulses having substantially a same phase and amplitude; and

a second detector for detecting nonlinear energy in response at least three pulses, a first one of the at least three pulses having a different phase than a second one of the at least three pulses;

wherein the first and second detectors are operable to detect within 500 milliseconds.

29. The system of claim 28 further comprising:

a processor operable to compare detected motion or loss-of-correlation output from the first detector with a threshold and select the detected motion or loss-of-correlation if the detected motion or loss-of-correlation is above the threshold, but select detected nonlinear response output from the second detector if the detected motion or loss-of-correlation is below the threshold.

30. The system of claim 28 further comprising:

a transmit beamformer operable to transmit the first and second pulses and a fifth pulse with at a first peak amplitude represented as [1 1 1]; and

wherein the first detector is operable to weight first, second and third receive echo signals responsive to the first, second and fifth pulses with first, second and third weights, respectively, corresponding to relative amplitudes and phases of [1 −

2 1].