Finite amplitude distortion-based inhomogeneous pulse echo ultrasonic imaging

• US 20050033180A1
• Filed: 08/18/2004
• Published: 02/10/2005
• Est. Priority Date: 11/08/1996
• Status: Active Grant

• Current Assignee: Research Corporation Technologies
• Original Assignee: Research Corporation Technologies
• Inventors: Christopher, Ted
• Granted Patent: US 7,513,870 B2
• Time in Patent Office: Days
• US Class Current: 600/458
• CPC Class Codes: G01S 15/895 characterised by the transmitted frequency spectrum
• CPC Class Codes: G01S 7/52038 involving non-linear properties of the propagation medium or of the reflective target
• CPC Class Codes: G01S 7/52046 Techniques for image enhancement involving transmitter or receiver image enhancement by image data processing G06T5/00

Abstract

A method and system for imaging a sample. The method includes the steps of generating an ultrasonic signal, directing the signal into a sample, which signal is distorted and contains a first order and higher order component signals at first and higher frequencies respectively. The received distorted signal is processed, and an image is formed, and then displayed, from one of the higher order component signals of the received distorted signal.

Claims

1-22. -22. (Cancelled).

23. An ultrasound tissue harmonic imaging method, comprising the steps of:

providing a biological tissue sample;

generating a transmit ultrasonic signal at a fundamental frequency;

transmitting the ultrasound signal into and along a propagation path in the sample, wherein the tissue distorts the transmit ultrasonic signal along the propagation path and thereby produces a distorted ultrasonic signal including harmonic components at second and higher order harmonic frequencies to the fundamental frequency, and further wherein the sample also reflects and scatters the distorted ultrasonic signal including said harmonic components;

receiving the harmonic components of the reflected or scattered distorted ultrasonic signal;

using a band pass filter to filter the received harmonic components to enhance the relative signal strength of one or more of the received harmonic components;

producing an ultrasound image of the biological tissue sample from said one or more of the received harmonic components; and

displaying the produced ultrasound image of the biological tissue sample.

24. An ultrasound tissue harmonic imaging method according to claim 23, wherein the band pass filter is a high pass filter to filter the received harmonic components.

25. An ultrasound tissue harmonic imaging method according to claim 23, wherein the band pass filter is a notched filter centered at the second harmonic component so as to receive primarily the second harmonic component.

26. An ultrasound tissue harmonic imaging method according to claim 23, wherein said one of the received harmonic components is the second harmonic component.

27. An ultrasound tissue harmonic imaging method according to claim 23, wherein the band pass filter selects the harmonic components and removes the fundamental component.

28. An ultrasound tissue harmonic imaging system for imaging a biological tissue sample, comprising:

means for generating a transmit ultrasonic signal at a fundamental frequency and transmitting the signal into and along a propagation path in the sample, wherein the sample distorts the transmit signal along the propagation path and thereby produces a distorted ultrasonic signal including harmonic components at second and higher order harmonic frequencies of the fundamental frequency, and further wherein the sample also reflects or scatters the distorted ultrasonic signal including said harmonic components;

means for receiving the harmonic components of the reflected distorted ultrasonic signal;

a band pass filter for filtering the received harmonic components to enhance the relative strength of one or more of the received harmonic components;

means for producing an image of the biological tissue sample from said one or more of the received harmonic components; and

means for displaying the produced image.

29. An ultrasound tissue harmonic imaging system according to claim 28, wherein the band pass filter is a high pass filter to filter the received harmonic component.

30. An ultrasound tissue harmonic imaging system according to claim 28, wherein the band pass filter is a notched filter centered at the second harmonic component so as to receive primarily the second harmonic component.

31. An ultrasound tissue harmonic imaging system according to claim 28, wherein said one of the received harmonic components is the second harmonic component.

32. A system according to claim 28, wherein the band pass filter selects the harmonic components and removes the fundamental component.

33. A method for reducing speckle in an ultrasound tissue image, comprising the steps of:

providing a biological tissue sample;

generating a transmit ultrasonic signal at a fundamental frequency;

directing the transmit signal into and along a propagation path in the sample, wherein the tissue distorts the transmit signal along the propagation path and thereby produces a distorted ultrasonic signal including a fundamental component at the fundamental frequency and harmonic components at second and higher order harmonic frequencies of the fundamental frequency, and further wherein the sample also reflects the distorted ultrasonic signal including said fundamental and harmonic components;

receiving the fundamental component and the harmonic components of the reflected distorted ultrasonic signal;

forming an ultrasound image of the biological tissue sample using two or more of the received components to reduce speckle in the image; and

displaying the formed image.

34. A method for reducing speckle in an ultrasound tissue harmonic image according to claim 33, further comprising the step of filtering the received components to enhance the relative strength of one or more of the received components.

35. A method for reducing speckle in an ultrasound tissue harmonic image according to claim 33, wherein:

the forming step includes the step of forming the image from the sum of the fundamental component and one or more of the harmonic components of the received distorted ultrasonic signal.

36. A method for reducing speckle in an ultrasound tissue harmonic image according to claim 35, wherein the speckle pattern of said one or more of the harmonic components of the received signal is out of phase with the speckle pattern of said fundamental component of the received signal.

37. A method for reducing speckle in an ultrasound tissue harmonic image according to claim 36, wherein said one or more of the harmonic components is the second harmonic component of the received signal.

38. A method for reducing speckle in an ultrasound tissue harmonic image according to claim 37, wherein:

each of the second harmonic component of the received signal and the fundamental component of the received signal has a respective mainlobe; and

the second harmonic component and the fundamental component of the received signal have a largely constant phase relationship in their mainlobes.

39. A system for reducing speckle in an ultrasound tissue harmonic image of a biological tissue sample, comprising:

means for generating a transmit ultrasonic signal at a fundamental frequency and for directing the transmit signal into and along a propagation path in the sample, wherein the sample distorts the transmit signal along the propagation path and thereby produces a distorted ultrasonic signal including fundamental component at a fundamental frequency and harmonic components at second and higher order harmonic frequencies of the fundamental frequency, and further wherein the sample also reflects the distorted ultrasonic signal including said fundamental and harmonic components;

means for receiving the fundamental and harmonic components of the reflected distorted ultrasonic signal;

means for forming an ultrasound image of the biological tissue sample using two or more of the received components to reduce speckle in the image; and

means for displaying the formed image.

40. A system for reducing speckle in an ultrasound tissue harmonic image according to claim 39, further comprising means for filtering the received components to enhance the relative strength of one or more of the received components.

41. A system for reducing speckle in an ultrasound tissue harmonic image according to claim 39, wherein:

the forming means includes means for forming the image from the sum of the fundamental component and one or more of the harmonic components of the received distorted ultrasonic signal.

42. A system for reducing speckle in an ultrasound tissue harmonic image according to claim 41, wherein the speckle pattern of said one or more of the harmonic components of the received signal is out of phase with the speckle pattern of said fundamental component of the received signal.

43. A system for reducing speckle in an ultrasound tissue harmonic image according to claim 41, wherein said one or more of the harmonic components is the second harmonic component of the received signal.

44. A system for reducing speckle in a tissue harmonic image according to claim 43, wherein:

each of the second harmonic component of the received signal and the fundamental component of the received signal has a respective mainlobe; and

the second harmonic component and the fundamental component of the received signal have a largely constant phase relationship in their mainlobes.