Device and method for mapping and tracking blood flow and determining parameters of blood flow

• US 20040019278A1
• Filed: 12/20/2002
• Published: 01/29/2004
• Est. Priority Date: 05/26/2000
• Status: Active Grant

• Current Assignee: PhysioSonics, Inc.
• Original Assignee: PhysioSonics, Inc.
• Inventors: Abend, Kenneth
• Granted Patent: US 7,534,209 B2
• Time in Patent Office: Days
• US Class Current: 600/454
• CPC Class Codes: G01S 15/8979 Combined Doppler and pulse-echo imaging systems
• CPC Class Codes: G01S 15/8993 Three dimensional imaging systems
• 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 7/52034 Data rate converters
• CPC Class Codes: G01S 7/5206 Two-dimensional coordinated display of distance and direction; B-scan display
• CPC Class Codes: G01S 7/52061 Plan position indication (PPI display); C-scan display
• CPC Class Codes: G01S 7/52065 Compound scan display, e.g. panoramic imaging
• 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: G01S 7/52073 Production of cursor lines, markers or indicia by electronic means
• CPC Class Codes: G01S 7/52074 Composite displays, e.g. split-screen displays; Combination of multiple images or of images and alphanumeric tabular information
• CPC Class Codes: G01S 7/52079 Constructional features constructional features of transducers B06B; mounting transducers G10K11/00; constructional features of ultrasonic medical diagnostic devices A61B8/44

Abstract

Provided herein is a method for use in medical applications that permits (1) affordable three-dimensional imaging of blood flow using a low-profile easily-attached transducer pad, (2) real-time blood-flow vector velocity, and (3) long-term unattended Doppler-ultrasound monitoring in spite of motion of the patient or pad. The pad and associated processor collects and Doppler processes ultrasound blood velocity data in a three dimensional region through the use of a planar phased array of piezoelectric elements. The invention locks onto and tracks the points in three-dimensional space that produce the locally maximum blood velocity signals. The integrated coordinates of points acquired by the accurate tracking process is used to form a three-dimensional map of blood vessels and provide a display that can be used to select multiple points of interest for expanded data collection and for long term continuous and unattended blood flow monitoring. The three dimensional map allows for the calculation of vector velocity from measured radial Doppler.

A thinned array (greater than half-wavelength element spacing of the transducer array) is used to make a device of the present invention inexpensive and allow the pad to have a low profile (fewer connecting cables for a given spatial resolution). The full aperture is used for transmit and receive so that there is no loss of sensitivity (signal-to-noise ratio) or dynamic range. Utilizing more elements (extending the physical array) without increasing the number of active elements increases the angular field of view. A further increase is obtained by utilizing a convex non-planar surface.

Claims

10. A method for determining a parameter of blood flow in a blood vessel of interest, comprising the steps of:

a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) directing sonic energy produced by the at least one element of the array into a volume of the subject'"'"'s body having the blood vessel of interest,

c) receiving echoes of the sonic energy from the volume of the subject'"'"'s body having the blood vessel of interest;

d) reporting the echoes to a processor programmed to

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) calculate a three dimensional position of blood flow in the vessel of interest; and

iii) calculate the parameter of blood flow in the blood vessel at the three dimensional position calculated in step (ii); and

(e) displaying the parameter on a display monitor that is electrically connected to the processor.

1. A method for determining a parameter of blood flow in a blood vessel of interest, comprising the steps of:

a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) directing sonic energy produced by the at least one element of the array into a volume of the subject'"'"'s body having the blood vessel of interest,

c) receiving echoes of the sonic energy from the volume of the subject'"'"'s body having the blood vessel of interest;

d) reporting the echoes to a processor electrically connected to the elements of the array, wherein the processor is programmed to

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from a portion of the blood vessel of interest;

iii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest,

iv) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and

v) calculate the parameter of blood flow in the blood vessel at the three dimensional position calculated in step (iv); and

(e) displaying the parameter on a display monitor that is electrically connected to the processor.

4. The method of claim 1, wherein the processor also determines at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy.

5. The method of claim 4, wherein the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

6. The method of claim 1, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

7. The method of claim 1, wherein steps (b) through (e) are periodically repeated so that the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest is tracked, and the parameter of blood flow is periodically calculated and displayed on the display monitor.

8. The method of claim 7, wherein the period of time between repeating steps (b) through (e) is sufficiently short so that the parameter being measured remains constant.

9. The method of claim 8, wherein the period between repeating steps (b) through (e) is about 20 milliseconds.

11. The method of claim 10, wherein the parameter of blood flow is determined for a particular region of the blood vessel of interest.

12. The method of claim 10, wherein the parameter of blood flow is selected from the group consisting of blood flow volume, vector velocity, and Doppler spectral distribution.

13. The method of claim 10, wherein the paramter being measured can be an instantaneous value, or an average value determined over a heart cycle.

14. The method of claim 10, wherein the step of having the programmed processor calculate the three dimensional position of blood flow in the vessel of interest comprises having the processor programmed to:

i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest;

ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, and

iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest.

15. The method of claim 14, wherein the processor also determines at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy.

16. The method of claim 15, wherein the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

17. The method of claim 10, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

18. The method of claim 10, wherein steps (b) through (e) are periodically repeated so that the three dimensional position of blood flow in the vessel of interest is tracked, and the parameter of blood flow is periodically calculated and displayed on the display monitor.

19. The method of claim 18;

wherein the period of time between repeating steps (b) through (e) is sufficiently short so that the parameter being measured remains constant.

20. The method of claim 19, a wherein the period between repeating steps (b) through (e) is about 20 milliseconds.

20-1. The method of claim 19, wherein the parameter of blood is selected from the group consisting of blood flow volume, vector velocity, and Doppler spectral distribution.

The parameter being measured can be an instantaneous value, or an average value determined over a heart cycle.

21. A method for determining a parameter of blood flow in a particular region of a blood vessel of interest, comprising the steps of:

a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) directing sonic energy produced by the at least one element of the array into a volume of the subject'"'"'s body having the particular region of the blood vessel of interest,

c) receiving echoes of the sonic energy from the volume of the subject'"'"'s body having the particular region of the blood vessel of interest;

d) reporting the echoes to a processor programmed to

i) Doppler process the echoes to determine radial velocity of the blood flowing in the particular region of the blood vessel of interest;

ii) calculate a three dimensional position of blood flow in the particular region of the blood vessel of interest; and

iii) calculate the parameter of blood flow in the particular region of the blood vessel of interest at the three dimensional position calculated in step (ii); and

(e) displaying the parameter on a display monitor that is electrically connected to the processor.

22. The method of claim 21, wherein the step of having the programmed processor calculate the three dimensional position of blood flow in the vessel of interest comprises having the processor programmed to:

i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the particular region of the blood vessel of interest;

ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes received from the flow of blood in the particular region of the blood vessel of interest, and

iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the particular region of the blood vessel of interest.

23. The method of claim 22, wherein the processor also determines at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy.

24. The method of claim 22, wherein the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

25. The method of claim 21, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

26. The method of claim 21 wherein steps (b) through (e) are periodically repeated so that the three dimensional position of blood flow in the particular region of the blood vessel of interest is tracked, and the parameter of blood flow is periodically calculated and displayed on the display monitor.

27. The method of claim 26, wherein the period of time is sufficiently short of time so that the parameter remains constant.

28. The method of claim 27, wherein the period between repeating steps (b) through (e) is about 20 milliseconds.

29. A method for determining a parameter of blood flow in a blood vessel of interest, comprising the steps of:

a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) directing sonic energy produced by the at least one element of the array into a volume of the subject'"'"'s body having the blood vessel of interest,

c) receiving echoes of the sonic energy from the volume of the subject'"'"'s body having the blood vessel of interest;

d) reporting the echoes to a processor electrically connected to the elements of the array, wherein the processor is programmed to

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest;

iii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest,

iv) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and

v) calculate the parameter of blood flow in the blood vessel at the three dimensional position calculated in step (iv); and

(e) displaying the parameter on a display monitor that is electrically connected to the processor.

2. The method of claim 1, wherein the parameter of blood is selected from the group consisting of blood flow volume, vector velocity, and Doppler spectral distribution.

30. The method of claim 29, wherein the parameter of blood is selected from the group consisting of blood flow volume, vector velocity, and Doppler spectral distribution.

31. The method of claim 29, wherein the parameter being measured can be an instantaneous value, or an average value determined over a heart cycle.

32. The method of claim 29, wherein the parameter is determined for blood flow in a particular region of the blood vessel of interest.

33. The method of claim 29, wherein the processor also determines at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy.

34. The method of claim 33, wherein the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

35. The method of claim 29, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

36. The method of claim 29, wherein steps (b) through (e) are periodically repeated so that the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest is tracked, and the parameter of blood flow is periodically calculated and displayed on the display monitor.

37. The method of claim 36, wherein the period of time between repeating steps (b) through (e) is sufficiently short so that the highest Doppler energy from the blood flow remains constant.

38. The method of claim 37, wherein the period between repeating steps (b) through (e) is about 20 milliseconds.

39. A method for determining a parameter of blood flow in a particular region of a blood vessel of interest, comprising the steps of:

a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) directing sonic energy produced by the at least one element of the array into a volume of the subject'"'"'s body having the particular region of the blood vessel of interest,

c) receiving echoes of the sonic energy from the volume of the subject'"'"'s body having the particular region of blood vessel of interest;

d) reporting the echoes to a processor electrically connected to the elements of the array, wherein the processor is programmed to

i) Doppler process the echoes to determine radial velocity of the blood flowing in the particular region of the blood vessel of interest;

ii) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the particular region of the blood vessel of interest;

iii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the particular region of the blood vessel of interest,

iv) calculate the three dimensional position of the highest Doppler energy from the blood flow in the particular region of the blood vessel of interest; and

v) calculate the parameter of blood flow in the particular region of the blood vessel at the three dimensional position calculated in step (iv); and

(e) displaying the parameter on a display monitor that is electrically connected to the processor.

39-2. The device of claim 38, wherein the parameter of blood is selected from the group consisting of blood flow volume, vector velocity, and Doppler spectral distribution.

40. A device for determining a parameter of blood flow in a blood vessel of interest, comprising:

a) an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, and at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) a processor electrically connected to the array so that echoes received from a volume of the subject'"'"'s body having the blood vessel of interest due to directing sonic energy produced by the at least one element of the array into the subject'"'"'s body is reported to the processor, wherein the processor is programmed to;

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) calculate a three dimensional position of blood flow in the blood vessel of interest; and

iii) calculate the parameter of blood flow in the blood vessel of interest at the three dimensional position calculated in step (ii); and

(c) a display monitor that is electrically connected to the processor which displays the parameter of blood flow calculated by the processor.

3. The method of claim 1, wherein the parameter being measured can be an instantaneous value, or an average value determined over a heart cycle.

41. The device of claim 40, wherein the processor is programmed to:

i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest after Doppler processing the echoes;

ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest,

iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and

iv) calculate the parameter of blood flow in the blood vessel of interest at the three dimensional position calculated in (iii).

42. The device of claim 40, wherein the parameter of blood flow is selected from the group consisting of vector velocity, blood flow volume, and Doppler spectral distribution.

43. The device of claim 40, wherein the parameter being measured can be an instantaneous value, or an average value determined over a heart cycle.

44. The device of claim 41, wherein the processor is further programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy.

45. The device of claim 44, wherein the the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

46. The device of claim 40, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

47. A device for determining a parameter of blood flow in a blood vessel of interest, comprising:

a) an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, and at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) a processor electrically connected to the array so that echoes received from a volume of the subject'"'"'s body having the blood vessel of interest due to directing sonic energy produced by the at least one element of the array into the subject'"'"'s body is reported to the processor, wherein the processor is programmed to;

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) calculate a three dimensional position of blood flow in the blood vessel of interest; and

iii) calculate the parameter of blood flow in the blood vessel of interest at the three dimensional position calculated in step (ii)

(c) a display monitor that is electrically connected to the processor which displays the parameter of blood flow calculated by the processor.

48. The device of claim 46, wherein the parameter is selected from the group consisting of blood flow volume, vector velocity, and Doppler spectral distribution.

49. The device of claim 46, wherein the parameter being measured can be an instantaneous value, or an average value determined over a heart cycle.

50. The device of claim 46, wherein the processor is further programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy.

51. The device of claim 50, wherein the angle between the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

47-3. The device of claim 46, wherein the parameter is determined for blood flowing in a particular region of the blood vessel of interest.

52. A method for generating a three dimensional image using sonic energy of a blood vessel of interest in a subject, the method comprising the steps of:

a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) directing sonic energy produced by the at least one element of the array into a volume of the subject'"'"'s body having the blood vessel of interest,

c) receiving echoes of the sonic energy from the volume of the subject'"'"'s body having the blood vessel of interest;

d) reporting the echoes to a processor programmed to

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) calculate a three dimensional position of blood flow in the blood vessel of interest;

iii) repeat steps (i) through (ii) to generate a plurality of calculated three dimensional positions; and

vi) generate a three dimensional image of the blood vessel of interest from the plurality of calculated three dimensional positions; and

(e) displaying the three dimensional image on a display monitor that is electrically connected to the processor.

53. The method of claim 52, wherein the three dimensional image is generated for a particular region of the blood vessel of interest.

54. The method of claim 52, wherein the step of having the programmed processor calculate the three dimensional position comprises having the programmed processor:

i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest after Doppler processing the echoes;

ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, and

iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest, and

iv) repeat steps (i) through (iii) to generate a plurality of calculated three dimensional positions.

55. The method of claim 54, wherein the processor is also programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, and the at least one additional beam is also used to modulate the directions of the transmitted and received sonic energy, and calculate the three dimensional position of the highest Doppler energy.

56. The method of claim 55, wherein the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

57. The method of claim 52, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

58. A method for generating a three dimensional image of a blood vessel of interest in a subject using sonic energy, the method comprising the steps of:

a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) directing sonic energy produced by the at least one element of the array into a volume of the subject'"'"'s body having the blood vessel of interest,

c) receiving echoes of the sonic energy from the volume of the subject'"'"'s body having the blood vessel of interest;

d) reporting the echoes to a processor programmed to

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from a portion of the blood vessel of interest;

iii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest,

iv) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and

v) repeat steps (i) through (iv) to generate a plurality of calculated three dimensional positions;

vi) generate a three dimensional image of the blood vessel of interest from the plurality of calculated three dimensional positions; and

(e) displaying the three dimensional image on a display monitor that is electrically connected to the processor.

59. The method of claim 58, wherein the three dimensional image is generated for a particular region of the blood vessel of interest.

60. The method of claim 58, wherein the processor also determines at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, and the at least one additional beam is also used to modulate the directions of the transmitted and received sonic energy, and calculate the three dimensional position of the highest Doppler energy.

61. The method of claim 60, wherein the the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

62. The method of claim 58, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

63. A device generating a three dimensional image of a blood vessel of interest in a subject using sonic energy, comprising:

a) an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, and at least one element transmits sonic energy, and a portion of the elements receive sonic energy;

b) a processor electrically connected to the array so that echoes received from a volume of the subject'"'"'s body having the blood vessel of interest due to directing sonic energy produced by the at least one element of the array into the subject'"'"'s body is reported to the processor, wherein the processor is programmed to;

i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest;

ii) calculate a three dimensional position of blood flow in the blood vessel of interest;

iii) repeat steps (i) through (ii) to generate a plurality of calculated three dimensional positions;

v) generate a three dimensional image from the plurality of calculated three dimensional positions, and

(c) a display monitor that is electrically connected to the processor which displays the three dimensional image.

64. The device of claim 63, wherein the three dimensional image is generated for a particular region of the blood vessel of interest.

65. The device of claim 63, wherein the processor is programmed to:

i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest after Doppler processing the echoes;

ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest,

iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and

iv) repeat steps (I) through (iii) in order to generate a plurality of calculated three dimensional positions used to generate the three dimensional image.

66. The device of claim 65, wherein the processor is further programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy.

67. The device of claim 65, wherein the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest.

68. The device of claim 63, wherein the distance between the elements of the array is greater than ½

the wavelength of the sonic energy generated by the at least one element.

69. A thinned array for use in an ultrasound device, comprising a plurality of sonic transducer elements, wherein the element spacing in the array is greater than a half wavelength of the sonic energy produced by the elements, and the elements are positioned and sized within the array, and sonic energy is electronically steered by the elements so that any grating lobes produced by the sonic energy are suppressed.