Ultrasound transceiver system for remote operation through a minimal number of connecting wires

• US 6,540,677 B1
• Filed: 11/15/2001
• Issued: 04/01/2003
• Est. Priority Date: 11/17/2000
• Status: Expired due to Term

• Current Assignee: PreXion Corporation (Funai Electric Co., Ltd.)
• Original Assignee: Bjorn A.J. Angelsen, Tonni F. Johansen
• Inventors: Johansen, Tonni F., Angelsen, Bjorn A. J.
• Primary Examiner(s): Jaworski, Francis J.
• Assistant Examiner(s): Jung, William C
• Application Number:
  US10/000,669
• Time in Patent Office: 502 Days
• Field of Search: 600/437, 310/314-317, 367/117-130
• US Class Current: 600/437
• CPC Class Codes: B06B 1/0215 for generating pulses, e.g. bursts of oscillations, envelopes
• CPC Class Codes: G01S 15/8922 the array being concentric or annular
• CPC Class Codes: G01S 7/52025 for pulse systems G01S7/52034 takes precedence
• 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
• CPC Class Codes: G01S 7/5208 with integration of processing functions inside probe or scanhead

Abstract

An advantageous combination of preamplifier electronics and circuits for acoustic beam forming with ultrasound transducer arrays permits integration of the electronics and transducer(s) at close distances in a compact arrangement and is operable from an ultrasound imaging or measurement system using only a minimal number of connecting electric wires. To achieve dynamic focusing of the receive beam with a transducer array, an integrated electronic circuit mounted in close proximity to the transducer array provides preamplifiers for the individual elements and delay circuits that are automatically switched in a predetermined time sequence after transmission of an imaging pulse. When a high voltage pulse is transmitted via the cable, a breakthrough circuit connects the cable to the transducer for transmission of the ultrasound pulse, while in receive mode the low level signal on the transducer is amplified and fed as a higher level signal via the same cable to the imaging or measurement instrument.

Claims

1. An ultrasound pulse echo transceiver system to operate at a distance from an ultrasound measurement or imaging system through a minimal set of wires comprising,

the transceiver system being composed of at least one ultrasound transducer element and an electronic circuit being mounted close to the transducer element and containing at least a receiver amplifier and a transmit switch,

the DC bias voltage to the electronic circuit being provided from the ultrasound instrument via a bias wire,

the transducer element being electrically connected to the input of the receiver amplifier, the amplifier input being designed so that that it tolerates large AC transmit pulse voltages at the transducer electrodes,

the output of the receiver amplifier being fed to the ultrasound instrument through a receiver wire, possibly through other electronic circuits,

the transmit switch being on one terminal connected to the hot electrode of the transducer element and on the other terminal connected to a transmit wire that feeds high voltage AC pulses from the ultrasound instrument, possibly through a buffer amplifier that is part of the transceiver, for transmission of ultrasound pulses from the transducer.

2. An ultrasound pulse echo transceiver system according to claim 1, where at least two of the receive, bias, and transmit wires are connected and merged to a single wire to reduce the number of wires connecting the transceiver to the ultrasound instrument.

3. An ultrasound transceiver system according to claim 2, where the receive, bias, and transmit wires are connected and merged to a single wire, so that the transceiver is operable from the ultrasound instrument through a two wire cable including ground connection to the transceiver system.

4. An ultrasound pulse echo transceiver system according to claim 1, where the transmit switch is composed of at least one diode that automatically switches to a low series AC impedance with a high AC voltage transmit pulse at the transmit wire, and automatically switches to a high AC impedance with the level of the AC signal at the transmit wire being below a defined level.

5. An ultrasound pulse echo transceiver system according to claim 1, where the transmit switch is composed of switching transistors or diodes where the switching is controlled by a control signal, where the switch control signal is selected so that the switch is on during the transmit period, and is off during the receive period.

6. An ultrasound pulse echo transceiver system according to claim 5, where the transmit switch control signal is derived from the high voltage AC transmit pulse on the transmit wire, so that the switch is automatically set on by the transmit pulse and automatically set off in the receive period.

7. An ultrasound pulse echo transceiver system according to claim 1, where the ability of the receiver amplifier to withstand high AC transmit voltages at the transducer electrode, is obtained by a circuit with an impedance in series with the amplifier input.

8. An ultrasound pulse echo transceiver system according to claim 7, where the series circuit is a capacitor.

9. An ultrasound pulse echo transceiver system according to claim 7, where the series circuit is two diodes connected back to back with a bias current so that for low level signals at the transducer, the AC impedance of the diodes is low, while for high level AC signals at the transducer, the AC impedance of the diodes is high.

10. An ultrasound pulse echo transceiver system according to claim 7, where the series circuit is a receiver switch composed of switching transistors or diodes where the switching is controlled by a control signal, where the switch control signal is selected so that the receiver switch is off during the transmit period and is on during the receive period.

11. An ultrasound transceiver system according to claim 10, where the receive switch control voltage is derived from the high voltage transmit pulse, so that the receive switch is automatically switched off by the transmit pulse, and automatically switched on in the receive period.

12. An ultrasound imaging device for imaging of structures through narrow channels, where an ultrasound transceiver system according to claim 1 is mounted at the tip of an elongated insertion device and connected to an ultrasound imaging system through a small number of wires.

13. An ultrasound imaging device according to claim 12, where the tip of the elongated insertion device is direction steerable from the external end of the insertion device.

14. An ultrasound imaging device according to claim 13 where the elongated insertion device is a device for insertion into a living body for imaging of tissue structures in the living body.

15. An ultrasound imaging device according to claim 12 where the elongated insertion device is a device for insertion into a living body for imaging of tissue structures in the living body.

16. An ultrasound transducer according to claim 15 where the elongated insertion device is a catheter for ultrasound imaging of the wall and surrounding tissue of a vessel or the urethra or other narrow channels in a body.

41. An ultrasound imaging device for imaging of structures through narrow channels, where an ultrasound transceiver system according to claim 12 is mounted at the tip of an elongated insertion device and connected to an ultrasound imaging system through a small number of wires.

17. An ultrasound pulse echo array transceiver system to attain a selectable or dynamic focus in receive mode and to operate at a distance from an ultrasound measurement or imaging system through a minimal set of wires comprising,

the transceiver system being composed of an ultrasound transducer array of elements where each element has fixed focus and is coupled to fixed signal delay lines, and an electronic circuit being mounted close to the transducer array and containing an electronic receive summing circuit and at least one electronic receive focusing switch,

the DC-bias voltage to the electronic circuit being provided from the ultrasound instrument via a bias wire,

the signal from possibly one array element being coupled firmly to the summing circuit, while the signal from at least some array elements being coupled via controllable electronic receive focusing switches to the summing circuit, possibly after amplification of each signal in preamplifiers and/or delay of each signal in electronic delay lines that are part of the electronic circuit, the signal from the summing circuit being a focused receive signal that is transmitted to the ultrasound instrument via a receive wire,

the focus and signal delay for each element being determined so that by closing the focusing switches to the summing circuit for a selected group of elements, one obtains a selected active aperture and focus depth,

and so that one by closing the focus switches in a sequence so that one increases the number of elements connected to the summing circuit, one obtains an increasing active receive aperture with an increasing focus depth.

18. An ultrasound pulse echo array transceiver system according to claim 17, where at least part of the element signal delay is obtained by an acoustic delay line that is part of the acoustic path in front of the element, the material of the acoustic delay line having wave propagation velocity different from that of the object to be measured or imaged, so that the thickness of the delay line material determines at least part of the element signal delay.

19. An ultrasound pulse echo array transceiver system according to claim 18, where the wave velocity of the acoustic delay line material is higher than that of the object to be imaged, and the acoustic delay line material has an absorption that produces a net apodization of the ultrasound signal across the active aperture for reduction of beam side lobes.

20. An ultrasound pulse echo array transceiver system according to claim 17, where the signal delay of each element is at least partially obtained by mechanically forming, for example curving, the total array surface.

21. An ultrasound pulse echo array transceiver system according to claim 17, where the electronic circuit contains at least one electronic transmit switch with one terminal connected to the hot electrode of at least one of the transducer elements, and the other terminal connected to a transmit wire that feeds a high voltage AC transmit pulse from the ultrasound instrument, possibly through an electronic delay line and/or a buffer amplifier that are part of the transceiver, the transmit switch circuit having the ability to switch between low electric series impedance in the transmit period and high electric impedance in the receive period.

22. An ultrasound pulse echo array transceiver system according to claim 21, where at least one electronic transmit switch has the ability that the AC impedance automatically switches to a low value when a high voltage AC transmit pulse on the transmit wire, and automatically switches to a high AC impedance when the AC voltage on the transmit wire drops below a limit value.

23. An ultrasound pulse echo array transceiver system according to claim 22, where the switching component of the transmit switch is made of at least one diode.

24. An ultrasound pulse echo array transceiver system according to claim 21, where at least one electronic transmit switch can be switched on or off by a transmit switch control voltage.

25. An ultrasound pulse echo array transceiver system according to claim 24, where the switching element of the transmit switches with explicit control voltages is made of diodes or switching transistors.

26. An ultrasound pulse echo array transceiver system according to claim 21, where the electronic circuit contains at least two transmit switches connected to at least two transducer elements on the one terminal, and on the other terminal connected to the same transmit wire, possibly through electronic delay lines and/or buffer amplifiers that are part of the transceiver, where at least one of the transmit switches can be switched on or off by a control voltage, the transmit switch control voltages being selectable so that a group of active transmit transducer array elements can be selected, to select the width and the depth of focus of the active transmit aperture.

27. An ultrasound pulse echo array transceiver system according to claim 26, where the receive focus switches can selectively be switched on to select the receive aperture and focus, so that the combined transmit and receive beam form a narrow observation beam in defined depth ranges of the received signal.

28. An ultrasound pulse echo array transceiver system according to claim 27, where the received signal for each combined transmit and receive focus is used to measure or image in a depth range where the combined observation beam is narrow.

29. An ultrasound pulse echo array transceiver system according to claim 28, where the measurement or image is composed of a sequence of depth ranges with the transmit and receive foci selected for minimal width of the observation beam in each range.

30. An ultrasound pulse echo array transceiver system according to claim 26, where the transmit switch control voltages are selected in a sequence so that for a first transmit pulse, transducer elements with short focus depth is selected for the transmit aperture, and for a set of consecutive transmit pulses an increasing number of elements with deeper foci are connected, so that an increasing active transmit aperture with an increasing composite focus depth is obtained for each consecutive transmit pulse in the set.

31. An ultrasound pulse echo array transceiver system according to claim 30, where the transmit switch control voltages are selected by a transmit switch control voltage sequencer circuit part of the electronic circuit, in a sequence generated by either the high voltage AC transmit pulses at the transmit wire or special signaling from the ultrasound instrument on a signaling wire.

32. An ultrasound pulse echo array transceiver system according to claim 31, where the transmit switch control voltage sequencer is reset through special signaling on the transmit wire, for example a change in voltage level of the transmit wire over a period of time.

33. An ultrasound pulse echo array transceiver system according to claim 26, where the number of array elements connected to the transmit wire in the transmit period is controlled through signaling from the ultrasound instrument to the transceiver over at least one signaling wire.

34. An ultrasound pulse echo array transceiver system according to claim 26, where the control voltage to at least one transmit switch is derived from a high voltage AC transmit pulse at the input wire to the transmit switch.

35. An ultrasound pulse echo array transceiver system according to claim 26 where at least two of the bias, receive, transmit, and signaling wires are connected and merged to a single wire, to reduce the number of wires connecting the ultrasound instrument and the array transceiver.

36. An ultrasound pulse echo array transceiver system according to claim 26 where the bias, receive, transmit, and signaling wires are connected and merged to a single wire, so that a 2-wire cable including ground connection can be used for connection between the ultrasound instrument and the array transceiver.

37. An ultrasound pulse echo array transceiver system according to claim 17, where the number of array elements connected to the receive summing circuit is controlled through signaling from the ultrasound instrument to the transceiver over at least one signaling wire.

38. An ultrasound pulse echo array transceiver system according to claim 17, where the electronic circuit also contains a receive timing circuit for controlling the receive focusing switches, the receive timing circuit being reset at the pulse transmission and in a time sequence following the pulse transmission switches on the receive focus switches so that an increasing active receive aperture with increasing focus depth with time after the pulse transmission is obtained, to provide a dynamic focusing of the receive beam.

39. An ultrasound pulse echo array transceiver system according to claim 17 where at least two of the bias, receive, transmit, and signaling wires are connected and merged to a single wire, to reduce the number of wires connecting the ultrasound instrument and the array transceiver.

40. An ultrasound pulse echo array transceiver system according to claim 17 where the bias, receive, transmit, and signaling wires are connected and merged to a single wire, so that a 2-wire cable including ground connection can be used for connection between the ultrasound instrument and the array transceiver.