Ultrasound imaging using apparent point-source transmit transducer

• US 9,883,848 B2
• Filed: 05/15/2014
• Issued: 02/06/2018
• Est. Priority Date: 09/13/2013
• Status: Active Grant

• Current Assignee: Maui Imaging, Inc.
• Original Assignee: Maui Imaging, Inc.
• Inventors: Specht, Donald F., Call, Josef R.
• Primary Examiner(s): Peng, Bo J
• Application Number:
  US14/279,052
• Publication Number:
  US 20150080727A1
• Time in Patent Office: 1,363 Days
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: A61B 8/4483 characterised by features of the ultrasound transducer
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• 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: G01S 15/8913 using separate transducers for transmission and reception
• CPC Class Codes: G01S 15/8915 using a transducer array
• CPC Class Codes: G01S 15/8929 using a three-dimensional transducer configuration
• CPC Class Codes: G01S 15/8993 Three dimensional imaging systems
• CPC Class Codes: G01S 15/8995 Combining images from different aspect angles, e.g. spatial compounding
• CPC Class Codes: G01S 15/8997 using synthetic aperture techniques
• CPC Class Codes: G01S 7/52077 with means for elimination of unwanted signals, e.g. noise or interference
• 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

An apparent point-source transmit transducers comprises a substantially constant-thickness shell of piezoelectric material in a shape of a spherical-section. Such transducers may be sized such that a single apparent point-source transmit transducer may produce ultrasound waveforms with substantial energy in a medium to be imaged. Use of such transducers in three-dimensional ping-based imaging may permit deeper and higher quality imaging than may be possible with conventional transducers.

Claims

1. A method of imaging an object with ultrasound energy, the method comprising the steps of:

transmitting an un-focused ultrasound signal into a target medium from apparent point-source transmit transducer comprising a shell of piezoelectric material shaped as a spherical section with a spherical center point;

receiving echoes reflected by a reflector in the target medium with an omnidirectional receive transducer element that is different than the apparent point-source transmit transducer;

determining a position of the reflector within the target medium by obtaining element position data describing a position of the spherical center point of the apparent point-source transmit transducer and a position of the receive transducer element, calculating a total path distance as a sum of a first distance between the spherical center point and the reflector and a second distance between the reflector and the receive transducer element, wherein calculating the total path distance comprises adding an apparent path segment representing a distance from a convex transmit transducer surface of the apparent point-source transmit transducer to the spherical center point, and determining a locus of possible points at which the reflector may lie; and

producing an image of the reflector.

2. The method of claim 1, wherein the receive transducer element comprises a shell of piezoelectric material shaped as a spherical section with a second spherical center point and wherein the position of the receive transducer element is a position of the second spherical center point.

3. The method of claim 1, wherein the position of the receive transducer element lies on a surface of the receive transducer element.

4. The method of claim 1, further comprising repeating the receiving, determining, and producing steps with a plurality of receive transducer elements in a common receive aperture.

5. The method of claim 4, further comprising repeating the receiving, determining, and producing with elements of a plurality of receive apertures.

6. The method of claim 1, further comprising repeating the transmitting step with a separate second, apparent point-source transmit transducer.

7. The method of claim 1, wherein a straight-line distance between the apparent point-source transmit transducer and the receive transducer element is greater than a maximum coherent aperture length for an intended imaging application.

8. The method of claim 1, wherein the receive transducer element has a circular shape.

9. A method of imaging an object with ultrasound energy, the method comprising the steps of:

transmitting an un-focused ultrasound signal into a target medium from apparent point-source transmit transducer comprising a shell of piezoelectric material shaped as a spherical section with a spherical center point;

receiving echoes reflected by a reflector in the target medium with an omnidirectional receive transducer element that is different than the apparent point-source transmit transducer;

determining a position of the reflector within the target medium by obtaining element position data describing a position of the spherical center point of the apparent point-source transmit transducer and a position of the receive transducer element, calculating a total path distance as a sum of a first distance between the spherical center point and the reflector and a second distance between the reflector and the receive transducer element, wherein calculating the total path distance comprises subtracting an apparent path segment representing a distance from a concave transmit transducer surface of the apparent point-source transmit transducer to the spherical center point, and determining a locus of possible points at which the reflector may lie; and

producing an image of the reflector.

10. The method of claim 9, wherein the receive transducer element comprises a shell of piezoelectric material shaped as a spherical section with a second spherical center point and wherein the position of the receive transducer element is a position of the second spherical center point.

11. The method of claim 9, wherein the position of the receive transducer element lies on a surface of the receive transducer element.

12. The method of claim 9, further comprising repeating the receiving, determining, and producing steps with a plurality of receive elements in a common receive aperture.

13. The method of claim 12, further comprising repeating the receiving, determining, and producing with elements of a plurality of receive apertures.

14. The method of claim 9, further comprising repeating the transmitting step with a separate second, apparent point-source transmit transducer.

15. The method of claim 9, wherein a straight-line distance between the apparent point-source transmit transducer and the receive transducer element is greater than a maximum coherent aperture length for an intended imaging application.

16. The method of claim 9, wherein the receive transducer element has a circular shape.