System and method for phase inversion ultrasonic imaging

• US 20030004414A1
• Filed: 08/21/2002
• Published: 01/02/2003
• Est. Priority Date: 05/31/2001
• Status: Active Grant

• Current Assignee: Shenzhen Mindray Bio-Medical Electronics Co., Ltd. (Excelsior Union Ltd.)
• Original Assignee: Zonare Medical Systems Incorporated (Excelsior Union Ltd.)
• Inventors: Ji, Ting-Lan, McLaughlin, Glen
• Granted Patent: US 7,226,416 B2
• Time in Patent Office: Days
• US Class Current: 600/437
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 8/00 Diagnosis using ultrasonic, sonic or infrasonic waves imaging of objects using sonar G01S15/00
• CPC Class Codes: A61B 8/485 involving measuring strain or elastic properties
• CPC Class Codes: A61B 8/488 involving Doppler signals
• 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 8/5223 for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012
• CPC Class Codes: A61B 8/5238 for combining image data of patient, e.g. merging several images from different acquisition modes into one image for image registration algorithms G06T7/30
• CPC Class Codes: G01S 15/104 wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
• CPC Class Codes: G01S 15/8959 using coded signals for correlation purposes
• CPC Class Codes: G01S 15/8963 using pulse inversion
• CPC Class Codes: G01S 7/52026 Extracting wanted echo signals Doppler systems G01S15/50; Doppler short range imaging systems G01S15/8979
• CPC Class Codes: G01S 7/52038 involving non-linear properties of the propagation medium or of the reflective target
• CPC Class Codes: G01S 7/52077 with means for elimination of unwanted signals, e.g. noise or interference

Abstract

A system and method for ultrasonic imaging utilizing multiple sets of transmit pulses differing in amplitude, frequency, phase, and/or pulse width. One embodiment has phase differences between the k transmit signal as $\frac{360}{k}degrees$

providing for constructive interference of the k^th order harmonic pulse, while an amplitude modulation of each transmit profile is constant between sets. These sets of pulses are transmitted into media of interest and received echoes from these pulses are combined to form an averaged signal. The averaged pulses represent the net common mode signal received from each of the transmit sets. This combined signal set is used to reconstruct an ultrasound image based on broad beam reconstruction methodology. It is emphasized that this abstract is provided to comply with the rules requiring an abstract. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims (37 C.F.R. §1.72(b)).

Claims

1. A system for ultrasonic imaging, comprising:

a signal generator unit for generating at least two out-of-phase pulses;

a signal transmitter unit coupled to said signal generator unit for transmitting said at least two out-of-phase pulses into media of interest;

a receiver and raw data averager unit for receiving said at least two out-of-phase pulses modified by said media of interest; and

a data processing unit coupled to said receiver and raw data averager unit.

2. The system of claim 1, wherein said signal generator unit is a digital waveform generator.

3. The system of claim 1, wherein said signal generator unit modulates an amplitude of at least two out-of-phase sine waves, which produce said at least two out-of-phase pulses.

4. The system of claim 1, wherein said signal generator unit modulates a frequency of at least two out-of-phase sine waves, which produce said at least two out-of-phase pulses.

5. The system of claim 1, wherein said signal generator unit modulates a pulse width of at least two out-of-phase sine waves, which produce said at least two out-of-phase pulses.

6. The system of claim 1, wherein said signal generator unit convolves at least two out-of-phase sine waves with an envelope function to produce said at least two out-of-phase pulses.

7. The system of claim 6, wherein said envelope function is a Gaussian waveform.

8. The system of claim 6, wherein said envelope function is a chirped waveform.

9. The system of claim 6, wherein said at least two out-of-phase sine waves are modulated in a way to produce a chirped Gaussian pulse width modulated waveform.

10. The system of claim 1 wherein said signal transmitter unit comprises a power amplifier, a transmit/receive switch, and a transducer.

11. The system of claim 10, further comprising a digital delay circuit.

12. The system of claim 10, further comprising an analog delay circuit.

13. The system of claim 10, further comprising a channel gain circuit.

14. The system of claim 1, wherein said at least two out-of-phase pulses are alternately transmitted by said signal transmitter unit to produce a pulse set.

15. The system of claim 1, wherein said receiver and raw data averager unit comprises a transducer, a transmit/receive switch, an analog-to-digital converter, and an averager.

16. The system of claim 15, wherein said receiver and raw data averager unit further comprises a power amplifier, a bandpass filter, and a baseband filter.

17. The system of claim 15, wherein said receiver and raw data averager unit further comprises an in-phase and quadrature mixer.

18. The system of claim 1, wherein said signal generator unit and said receiver and raw data averager unit share a transducer.

19. The system of claim 1, wherein said data processing unit comprises an in-phase and quadrature mixer, a digital signal processor, an acoustic image data buffer, and a scan converter.

20. The system of claim 1, wherein said data processing unit comprises an in-phase and quadrature mixer, an application specific integrated circuit, an acoustic image data buffer, and a scan converter.

21. The system of claim 1, further comprising an image display unit coupled to said data processing unit.

22. The system of claim 21, wherein said image display unit is a computer monitor.

23. The system of claim 21, wherein said image display unit is a flat-panel display.

24. The system of claim 21, wherein said image display unit is a liquid-crystal display.

26. The method of claim 25, wherein said at least two out-of-phase pulses are modulated by a change in amplitude.

27. The method of claim 25, wherein said at least two out-of-phase pulses are modulated by a change in frequency.

28. The method of claim 25, wherein said at least two out-of-phase pulses are modulated by a change in pulse width.

29. The method of claim 25, wherein said two out-of-phase pulses are convolved with an envelope function to produce said at least two out-of-phase pulses.

30. The method of claim 29, wherein said envelope function is a Gaussian waveform.

31. The method of claim 29, wherein said envelope function is a chirped waveform.

32. The method of claim 25, wherein a phase of said at least two out-of-phase pulses vary by 360 degrees divided by an integral denominator that is equal to an integral number of said at least two out-of-phase pulses.

33. The method of claim 25, wherein said averaging of said at least two modified acoustical pulses is a point-by-point arithmetic average for an element of a transmit cycle as a function of a channel number and a time to correlate back to said at least two acoustical out-of-phase pulses.

35. The system of claim 34, wherein said signal transmitter unit comprises a power amplifier, a transmit/receive switch, and a transducer.

36. The system of claim 35, further comprising a digital delay circuit.

37. The system of claim 35, further comprising an analog delay circuit.

38. The system of claim 35, further comprising a channel gain circuit.

39. The system of claim 34, wherein said receiver and raw data averager unit comprises a transducer, a transmit/receive switch, an analog-to-digital converter, and an averager.

40. The system of claim 39, wherein said receiver and raw data averager unit further comprises a power amplifier, a bandpass filter, and a baseband filter.

41. The system of claim 39, wherein said receiver and raw data averager unit further comprises an in-phase and quadrature mixer.

42. The system of claim 34, wherein said signal generator unit and said receiver and raw data averager unit share a transducer.

43. The system of claim 34, wherein said data processing unit comprises an in-phase and quadrature mixer, a digital signal processor, an acoustic image data buffer, and a scan converter.

44. The system of claim 34, wherein said data processing unit comprises an in-phase and quadrature mixer, an application specific integrated circuit, an acoustic image data buffer, and a scan converter.

25. A method for performing ultrasonic imaging, comprising:

generating at least two out-of-phase pulses;

converting said at least two out-of-phase pulses into at least two out-of-phase acoustical pulses;

transmitting said at least two out-of-phase acoustical pulses into media of interest;

receiving and averaging at least two modified acoustical pulses from said media of interest; and

constructing image data from said at least two modified acoustical pulses.

34. A system for ultrasonic imaging, comprising:

a signal generator unit for generating at least two out-of-phase pulses, wherein said signal generator unit may modulate at least two sine waves with an envelope function to produce a modified version of said at least two out-of-phase pulses, said signal generator unit further converting said at least two out-of-phase pulses into at least two out-of-phase acoustical pulses;

a signal transmitter unit coupled to said signal generator unit for transmitting said at least two out-of-phase acoustical pulses into media of interest;

a receiver and raw data averager unit for receiving said at least two acoustical pulses modified by said media of interest, wherein data from said at least two modified acoustical pulses are averaged in a data set as a function of channel number and time; and

a data processing unit coupled to said receiver and raw data averager unit, wherein said data processing unit constructs image data from said modified acoustical pulses, an output from said data processing unit is further coupled to an image display unit.

45. A method for performing ultrasonic imaging, comprising:

generating at least two out-of-phase pulses;

convolving said at least two out-of-phase pulses with an envelope function;

converting said at least two out-of-phase pulses into at least two out-of-phase acoustical pulses;

transmitting said at least two out-of-phase acoustical pulses into media of interest;

receiving at least two generated return pulses from said media of interest;

averaging data from said at least two generated return pulses as a function of channel number and time;

constructing image data from said at least two generated return pulses; and

displaying said image data on an image display unit.