High frequency array ultrasound system

• US RE46,185 E1
• Filed: 03/07/2013
• Issued: 10/25/2016
• Est. Priority Date: 11/02/2005
• Status: Active Grant

• Current Assignee: FUJIFILM SonoSite, Inc. (Fujifilm Holdings Corporation), Sunnybrook Health Sciences Centre
• Original Assignee: FUJIFILM SonoSite, Inc. (Fujifilm Holdings Corporation)
• Inventors: Mehi, James, Daigle, Ronald E., Brasfield, Laurence C., Starkoski, Brian, Wen, Jerrold, Liu, Kai Wen, Pflugrath, Lauren S., Foster, F. Stuart, Hirson, Desmond
• Primary Examiner(s): Lie, Angela M
• Application Number:
  US13/789,539
• Time in Patent Office: 1,328 Days
• Field of Search: 600/447, 702/75
• US Class Current: 1/1
• CPC Class Codes: A61B 8/56 Details of data transmission or power supply
• CPC Class Codes: A61B 8/565 involving data transmission via a network
• CPC Class Codes: G01S 15/8915 using a transducer array
• CPC Class Codes: G01S 15/8927 using simultaneously or sequentially two or more subarrays or subapertures
• CPC Class Codes: G01S 15/8956 using frequencies at or above 20 MHz
• CPC Class Codes: G01S 15/8959 using coded signals for correlation purposes
• CPC Class Codes: G01S 15/8997 using synthetic aperture techniques
• CPC Class Codes: G01S 7/52017 particularly adapted to short-range imaging G01S7/53 takes precedence
• CPC Class Codes: G01S 7/5202 for pulse systems
• CPC Class Codes: G01S 7/52034 Data rate converters
• CPC Class Codes: G01S 7/52088 involving retrospective scan line rearrangements medical diagnostic ultrasound devices involving retrospective matching to a physiological signal A61B8/5284
• CPC Class Codes: G01S 7/52095 using multiline receive beamforming
• CPC Class Codes: G01S 7/524 Transmitters
• CPC Class Codes: G01S 7/526 Receivers
• CPC Class Codes: G10K 11/341 Circuits therefor
• CPC Class Codes: G10K 11/346 using phase variation

Abstract

A system for acquiring an ultrasound signal comprises a signal processing unit adapted for acquiring a received ultrasound signal from an ultrasound transducer having a plurality of elements. The system is adapted to receive ultrasound signals having a frequency of at least 20 megahertz (MHz) with a transducer having a field of view of at least 5.0 millimeters (mm) at a frame rate of at least 20 frames per second (fps). The signal processing can further produce an ultrasound image from the acquired ultrasound signal. The transducer can be a linear array transducer, a phased array transducer, a two-dimensional (2-D) array transducer, or a curved array transducer.

Claims

1. An ultrasound imaging system, comprising:

an arrayed ultrasonic transducer having a plurality of elements for transmitting configured to transmit into a subject a transmitted ultrasound signal at a transmit center frequency of up to 55 15 megahertz (MHz) or greater;

and

a signal processing unit operatively connected with said arrayed ultrasonic transducer and comprising;

a digital transmit beamformer subsystem comprising one or more field programmable gate arrays (FPGA), each having an FPGA clock frequency (FPGA fc), said digital transmit beamformer subsystem having a delay resolution time of at least [1/(2×

FPGA fc)] or greater (1/(2×

FPGA fc)) or less,

a receive beamformer subsystem,

a front end electronics module,

a beamformer control module,

a signal processing module,

a parallel to serial converter, and

a computer unit;

wherein said signal processing unit is configured to acquire a received ultrasound signal having a frequency of at least 15 MHz from said arrayed ultrasound transducer, and wherein said digital transmit beamformer subsystem is configured to transmit an ultrasound signal having said transmit center frequency by encoding a fine delay and half-cycle sections of said transmitted ultrasound signal into bit words that are converted to a serial bit stream by said parallel to serial converter, wherein said transmitted ultrasound signal comprises a positive transmit pulse having a positive pulse width and a negative transmit pulse having a negative pulse width, and said positive pulse width and said negative pulse width are independently adjustable.

2. The ultrasound imaging system of claim 1, wherein said bit words are up to 16 bit words.

3. The ultrasound imaging system of claim 1, wherein said transmitted ultrasound signal further comprises (i) a plurality of positive half-wave cycle sections, each comprising at least one said positive transmit pulse and (ii) a plurality of negative half-wave cycle sections, each comprising at least one said negative transmit pulse.

4. The ultrasound imaging system of claim 1, wherein said transmitted ultrasound signal comprises an adjustable number of cycles transmitted.

5. The ultrasound imaging system of claim 1, wherein said front end electronics module is constructed as a replaceable plug-in module.

6. The ultrasound imaging system of claim 1, wherein said arrayed ultrasonic transducer is selected from the group consisting of a linear array transducer, a phased array transducer, a two-dimensional (2-D) array transducer, and a curved array transducer.

7. The ultrasound imaging system of claim 1, wherein said transmitted ultrasound signal has a transmit center frequency of 15 MHz up to 55 MHz.

8. The ultrasound imaging system of claim 1, wherein

said signal processing module utilizes quadrature sampling and has a receive sampling frequency,

wherein said signal processing unit is configured so that said receive sampling frequency may be selectively chosen.

9. The ultrasound imaging system of claim 1,

wherein said arrayed ultrasonic transducer has a field of view of at least 5.0 millimeters (mm);

and wherein said signal processing unit is adapted for acquiring configured to acquire a received ultrasound signal from said arrayed ultrasound transducer at a an acquisition frame rate of at least 20 frames per second (fps).

10. The system of claim 1, wherein:

saidthe arrayed ultrasound transducer is capable of generating and transmittingconfigured to generate and transmit into a subject ultrasound at a frequency of up to at least 55 megahertz (MHz)80 MHz and at a pulse repetition frequency (PRF) of at least 500 hertz (Hz), and

the arrayed ultrasound transducer is capable of receivingfuther configured to receive ultrasound from the subject,

the arrayed ultrasound transducer has a field of view of at least 5.0 millimeters (mm);

, and

wherein saidthe system further comprises a processing unit for generating configured to generate a color flow Doppler or pulsed wave Doppler ultrasound image from the received ultrasound.

11. The ultrasound imaging system of claim 1, wherein said FPGA fc is the highest operable frequency of the one or more FPGA FPGAs.

12. The ultrasound imaging system of claim 1, wherein said transmit center frequency is adjustable.

13. The ultrasound imaging system of claim 3, wherein each fine delay of said at least one said positive transmit pulse within each positive half wave cycle is adjustable, and each fine delay of said at least one said negative transmit pulse within each negative half wave cycle is adjustable.

29. The ultrasound imaging system of claim 8, wherein said receive sampling frequency is chosen at a frequency different from said transmit center frequency.

30. The ultrasound imaging system of claim 8, wherein said receive sampling frequency is chosen at a frequency the same as said transmit center frequency.

31. The ultrasound imaging system of claim 8, wherein said digital transmit beamformer subsystem further comprises a transmit focal dept depth such that said receive sampling frequency is dependent upon said transmit focal depth.

32. The ultrasound imaging system of claim 30, wherein said receive sampling frequency decreases as said transmit focal depth increases.

33. The system of claim 9, wherein the signal processing unit is further produces configured to produce an ultrasound image from the received ultrasound signal.

34. The system of claim 9, wherein the arrayed ultrasonic transducer has a center operating frequency of at least 15 MHz and the arrayed ultrasonic transducer has an element pitch equal to or less than 2.0 times the wavelength of sound at the arrayed ultrasonic transducer'"'"'s transmit center frequency.

35. The system of claim 9, wherein the arrayed ultrasonic transducer has an element pitch equal to or less than 1.5 times the wavelength of sound at the arrayed ultrasonic transducer'"'"'s transmit center frequency.

36. The system of claim 9, wherein the front end electronics module further comprises a transmit circuit and a receive channel, wherein the transmit circuit comprises a transmit supply voltage connected through two field-effect transistors (FETs) to a transformer with a center-tapped winding in which the arrayed ultrasonic transducer is operatively connected to a first end of a secondary winding of the transformer and an input to the receive channel is connected to a second end of the secondary winding of the transformer such that said transmit supply voltage is set to substantially zero and said two FETs are turned on when said receive channel is receiving a signal and said transformer generates a transmit signal and couples the transmit signal to the arrayed ultrasonic transducer when said transmit circuit is transmitting a signal.

37. The system of claim 9, wherein each element of said arrayed ultrasonic transducer having a plurality of elements is operatively connected to a receive channel.

38. The system of claim 9, wherein at least two lines of ultrasound are generated, transmitted into the subject and received from the subject at each element of the array for each frame of the generated ultrasound image.

39. The system of claim 9, wherein one line of ultrasound is generated, transmitted into the subject and received from the subject at each element of the array for each frame of the generated ultrasound image.

40. The system of claim 9, wherein the elements of the arrayed ultrasonic transducer having a plurality of elements are separated by a distance equal to the wavelength of the center transmit center frequency of the arrayed ultrasonic transducer.

41. The system of claim 9, wherein a length of the arrayed ultrasonic transducer having a plurality of elements is equal to a the field of view of the arrayed ultrasound transducer.

42. The system of claim 9, wherein the received ultrasound signal is acquired at a acquisition frame rate of is at least 200 fps.

43. The system of claim 9, wherein the received ultrasound signal is acquired at a acquisiton frame rate is within the range of about 100 fps to about 200 fps.

44. The system of claim 9, wherein the ultrasound image has a lateral resolution of about 150 microns (μ

m) or less.

45. The system of claim 9, wherein the signal processing unit is further configured to focus the transmitted ultrasound signal can be focused at a depth of about 1.0 mm to about 30.0 mm.

46. The system of claim 33, wherein the received ultrasound signal is processed by said signal processing unit to generate the ultrasound image at a display rate that is slower lower than the acquisition frame rate.

47. The system of claim 33, wherein the ultrasound image is produced by said signal processing unit in an ultrasound mode selected from the group consisting of B-mode, M-mode, Doppler mode, RF-mode, and 3-D mode.

48. The system of claim 46, wherein the display rate of the generated ultrasound image is 100 fps or less.

49. The system of claim 48, wherein the display rate of the generated ultrasound image is 30 fps or less.

50. The system of claim 36, wherein the front end electronics module further comprises two or more signal samplers for each receive channel.

51. The system of claim 50, wherein the signal samplers are analog to digital converters.

52. The system of claim 50, wherein the signal samplers are configured to use quadrature sampling to sample a received signal.

53. The system of claim 52, wherein the signal samplers comprise sampling clocks shifted 90 degrees out of phase.

54. The system of claim 53, wherein the sampling clocks have a receive clock period approximately equal to the center frequency of a received ultrasound signal.

55. The system of claim 54, wherein a delay resolution of less than the receive clock period is used to process the acquired received ultrasound signal.

56. The system of claim 55, wherein the delay resolution is 1/16 of the receive clock period.

57. The system of claim 37, wherein the number of elements of said arrayed ultrasonic transducer having a plurality of elements is greater than the number of receive channels.

58. The system of claim 37, wherein the arrayed ultrasonic transducer having a plurality of elements comprises at least 64 elements that are operatively connected to at least 32 receive channels.

59. The system of claim 37, wherein the arrayed ultrasonic transducer having a plurality of elements comprises 256 elements that are operatively connected to 64 receive channels.

60. The system of claim 37, wherein the arrayed ultrasonic transducer having a plurality of elements comprises 256 elements that are operatively connected to 128 receive channels.

61. The system of claim 37, wherein the arrayed ultrasonic transducer having a plurality of elements comprises 256 elements that are operatively connected to 256 receive channels.

62. The system of claim 37, wherein the arrayed ultrasonic transducer having a plurality of elements comprises 256 elements.

63. The system of claim 62, wherein 512 lines of ultrasound are generated, transmitted into the subject and received from the subject for each frame of the generated ultrasound image.

64. The system of claim 62, wherein 256 lines of ultrasound are generated, transmitted into the subject and received from the subject for each frame of the generated ultrasound image.

65. The system of claim 39, wherein the received ultrasound signals are acquired at an acquisition frame rate of is at least 200 frames per second (fps) fps.

66. The system of claim 40, wherein the center transmit center frequency is selected from the group consisting of 15 MHz, 20 MHz, 30 MHz, 40 MHz, 50 MHz, and 55 MHz.

67. The system of claim 44, wherein the ultrasound image has a an axial resolution of about 75 microns (μ

m) or less.

68. The system of claim 67, wherein the ultrasound image has a spatial resolution of about 30 microns (μ

m) or less.

69. The system of claim 45, wherein the signal processing unit is further configured to focus the transmitted ultrasound signal can be focused at a depth of about 3.0 mm to about 10.0 mm.

70. The system of claim 45, wherein the signal processing unit is further configured to focus the transmitted ultrasound signal can be focused at a depth of about 2.0 mm to about 12.0 mm.

71. The system of claim 45, wherein the signal processing unit is further configured to focus the transmitted ultrasound signal can be focused at a depth of about 1.0 mm to about 6.0 mm.

72. The system of claim 45, wherein the signal processing unit is further configured to focus the transmitted ultrasound signal can be focused at a depth of about 3.0 mm to about 8.0 mm.

73. The system of claim 45, wherein the signal processing unit is further configured to focus the transmitted ultrasound signal can be focused at a depth of about 5.0 mm to about 18.0 mm.

74. The system of claim 10, wherein the PRF is between about 500 Hz to about 75 KHz.

14. A signal processing unit for an arrayed ultrasound imaging system, the signal processing unit comprising:

a digital transmit beamformer subsystem configured to operate up to 55 MHz at a transmit center frequency of 15 Megahertz (MHz) or greater, wherein said digital transmit beamformer subsystem further comprises one or more field programmable gate arrays (FPGA), each having an FPGA clock frequency (FPGA fc), said digital transmit beamformer subsystem having a delay resolution time of at least [1/(2×

FPGA fc)] or greater (1/(2×

FPGA fc)) or less;

a digital receive beamformer subsystem;

a front end electronics module;

a beamformer control module;

a signal processing module;

a parallel to serial converter; and

a computer unit,

wherein said signal processing unit is configured to acquire a received ultrasound signal from an arrayed ultrasound transducer having a plurality of elements, and wherein said digital transmit beamformer subsystem is configured to transmit an ultrasound signal having said transmit center frequency by encoding a fine delay and half-cycle sections of said transmitted ultrasound signal into bit words that are converted to a serial bit stream by said parallel to serial converter, wherein said transmitted ultrasound signal comprises a positive transmit pulse having a positive pulse width and a negative transmit pulse having a negative pulse width, and said positive pulse width and said negative pulse width are independently adjustable.

15. The signal processing unit of claim 14, wherein said bit words are up to 16 bit words.

16. The signal processing unit of claim 14, wherein said transmitted ultrasound signal comprises an adjustable number of cycles transmitted.

17. The signal processing unit of claim 14, wherein said front end electronics module is constructed as a replaceable plug-in module.

18. The signal processing unit of claim 14, wherein said arrayed ultrasonic transducer is selected from the group consisting of a linear array transducer, a phased array transducer, a two-dimensional (2-D) array transducer, and a curved array transducer.

19. The signal processing unit of claim 14, wherein said transmit center frequency is 15 MHz up to 55 MHz.

20. The signal processing unit of claim 14, wherein said FPGA fc is the highest operable frequency of the one or more FPGA.

21. The signal processing unit of claim 14, wherein said transmit center frequency is adjustable.

22. A digital transmit beamformer for an arrayed ultrasound imaging system, the digital transmit beamformer comprising:

one or more FPGAs, each having an FPGA clock frequency (FPGA fc); and

a parallel to serial converter,

wherein said digital transmit beamformer is configured to transmit an ultrasound signal having a transmit center frequency up to 55 of 15 MHz or greater with a delay resolution time of at least [1/(2×

FPGA fc)] or greater (1/(2×

FPGA fc)) or less by encoding a fine delay and half-cycle sections of said transmitted ultrasound signal into bit words that are converted to a serial bit stream by said parallel to serial converter, wherein said transmitted ultrasound signal comprises a positive transmit pulse width and a negative transmit pulse width, and said transmit pulse width and said negative transmit pulse width are independently adjustable.

23. The digital transmit beamformer of claim 22, wherein said transmitted ultrasound signal comprises an adjustable number of cycles transmitted.

24. The digital transmit beamformer of claim 22, wherein said digital transmit beamformer is configured to be operatively connected with an arrayed ultrasonic transducer and said arrayed ultrasonic transducer is selected from the group consisting of a linear array transducer, a phased array transducer, a two-dimensional (2-D) array transducer, and a curved array transducer.

25. The digital transmit beamformer of claim 22, wherein said transmit center frequency is 15 MHz up to 55 MHz.

26. The digital transmit beamformer of claim 22, wherein said bit words are up to 16 bit words.

27. The digital transmit beamformer of claim 22, wherein said FPGA fc is the highest operable frequency of the one or more FPGA.

28. The digital transmit beamformer of claim 22, wherein said transmit center frequency is adjustable.