Methods and apparatus for performing sonomammography and enhanced x-ray imaging

• US 5,479,927 A
• Filed: 07/20/1994
• Issued: 01/02/1996
• Est. Priority Date: 10/29/1993
• Status: Expired due to Term

• Current Assignee: United States Surgical Corporation (Medtronic Plc)
• Original Assignee: Neovision LLC (Medtronic Plc)
• Inventors: Shmulewitz, Ascher
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US08/277,894
• Time in Patent Office: 531 Days
• Field of Search: 128/653.1, 128/660.01, 128/660.09, 128/660.08, 128/660.1, 128/661.01, 128/915, 378/37, 378/208
• US Class Current: 600/445
• CPC Class Codes: A61B 10/0233 Pointed or sharp biopsy instruments
• CPC Class Codes: A61B 17/3403 Needle locating or guiding means guides for suture needles A61B17/0482; guiding or tracking by nuclear magnetic resonance G01R33/285
• CPC Class Codes: A61B 2017/00902 transparent or translucent
• CPC Class Codes: A61B 2017/00924 for ultrasonic waves
• CPC Class Codes: A61B 2562/168 Fluid filled sensor housings
• CPC Class Codes: A61B 6/4417 related to combined acquisition of different diagnostic modalities
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography
• CPC Class Codes: A61B 6/5247 combining images from an ionising-radiation diagnostic technique and a non-ionising radiation diagnostic technique, e.g. X-ray and ultrasound
• CPC Class Codes: A61B 8/0825 for diagnosis of the breast, e.g. mammography
• CPC Class Codes: A61B 8/4209 by using holders, e.g. positioning frames
• CPC Class Codes: A61B 8/4272 involving the acoustic interface between the transducer and the tissue
• CPC Class Codes: A61B 8/4483 characterised by features of the ultrasound transducer
• 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: A61B 90/17 for soft tissue, e.g. breast-holding devices
• CPC Class Codes: Y10S 128/915 Ultrasound mammography

Abstract

Apparatus is provided that combines mammography equipment with an ultrasonic transducer to generate ultrasonic images of the internal structure of breast tissue that are in geometric registration with a mammogram. The apparatus includes a radiolucent and sonolucent compression plate, and in alternative embodiments, a gantry driven ultrasound transducer or a phased array ultrasonic transducer. Methods are provided for generating a mammogram and a plurality of corresponding ultrasound images without moving the breast between the mammogram exposure and the ultrasound imaging. Methods are also provided for viewing and analyzing the ultrasound images. Apparatus and methods are also provided for enhancing X-ray images obtained from conventional mammographic systems, and with reduced overall X-ray dosage to the patient.

Claims

1. In apparatus for obtaining images of biological tissue by passing X-ray radiation through a biological tissue to form an image in a receptor, the apparatus comprising an X-ray source for emitting X-ray radiation, first and second compression surfaces adapted for immobilizing the biological tissue therebetween, and a receptor disposed adjacent the second compression surface, the X-ray source disposed adjacent the first compression surface so that X-ray radiation emitted from the source passes through the biological tissue and is received by the receptor, the improvement comprising:

a compression plate that is radiolucent and sonolucent, the compression plate having first and second surfaces, the second surface forming the first compression surface;

an ultrasonic transducer disposed adjacent to the first surface of the compression plate; and

drive means for moving the ultrasonic transducer across the first surface of the compression plate while the biological tissue remains immobilized between the first and second compression surfaces.

2. The apparatus as defined in claim 1 wherein the compression plate comprises a material selected from the group consisting of Kapton®

, a Surlyn®

ionomer, and a polymethyl pentene.

3. The apparatus as defined in claim 2 wherein the polymethyl pentene is TPX®

.

4. The apparatus as defined in claim 2 wherein the material has a periphery and the material is coupled around the periphery to a rigid frame.

5. The apparatus as defined in claim 1 further comprising a gel pad for acoustically coupling a portion of the biological tissue to the ultrasonic transducer.

6. The apparatus as defined in claim 5 wherein the biological tissue has an X-ray attenuation characteristic, the gel pad is disposed between the first and second compression surfaces and in contact with the biological tissue, and the gel pad comprises a material that conforms to the shape of the biological tissue and has an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue.

7. The apparatus as defined in claim 6 wherein the gel pad reduces scattering of the X-ray radiation relative to scattering of the X-ray radiation in air.

8. The apparatus as defined in claim 5 wherein the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the compression plate imposes a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad conforms to the non-uniform shape to distribute the force over the surface area and reduce discomfort in the patient.

9. The apparatus as defined in claim 8 wherein the gel pad comprises an adherent surface that assists in positioning the biological tissue between the upper compression surface and the lower compression surface.

10. The apparatus as defined in claim 1 further comprising lubricating means for providing a film of fluid between the ultrasonic transducer and the compression plate to lubricate and acoustically couple the ultrasonic transducer to the compression plate.

11. The apparatus as defined in claim 1 wherein the drive means further comprises:

a gantry support;

a gantry movably engaged with the gantry support for movement in the distal and proximal directions;

a carriage movably engaged with the gantry for lateral movement.

12. The apparatus as defined in claim 11 wherein the drive means further comprises:

a first motorized cable arrangement for driving the gantry along the gantry support;

a second motorized cable arrangement for driving the carriage along the gantry; and

circuitry for controlling operation of the first and second motorized cable arrangements.

13. The apparatus as defined in claim 1 further comprising:

a biopsy instrument support;

means for aligning the biopsy instrument support with the ultrasonic transducer so that a medical practitioner may perform a biopsy guided by the plurality of ultrasonic images.

14. In apparatus for obtaining images of biological tissue by passing X-ray radiation through a biological tissue to form an image in a receptor, the apparatus comprising an X-ray source for emitting X-ray radiation, first and second compression surfaces adapted for immobilizing the biological tissue therebetween, and a receptor disposed adjacent the second compression surface, the X-ray source disposed adjacent the first compression surface so that X-ray radiation emitted from the source passes through the biological tissue and is received by the receptor, the improvement comprising:

an ultrasonic transducer disposed adjacent the second compression surface, the ultrasonic transducer being radiolucent;

a coupling medium that acoustically couples the ultrasonic transducer to the second compression surface; and

control circuitry for activating the ultrasonic transducer to generate a plurality of ultrasound images of the biological tissue while the biological tissue remains immobilized between the upper and lower compression surfaces.

15. The apparatus as defined in claim 14 further comprising a gel pad for acoustically coupling a portion of the biological tissue to the ultrasonic transducer.

16. The apparatus as defined in claim 14 wherein the biological tissue has an X-ray attenuation characteristic, the gel pad is disposed between the first and second compression surfaces and in contact with the biological tissue, and the gel pad comprises a material that conforms to the shape of the biological tissue and has an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue.

17. The apparatus as defined in claim 16 wherein the gel pad reduces scattering of the X-ray radiation relative to scattering of the X-ray radiation in air

18. The apparatus as defined in claim 14 wherein the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the first and second compression surfaces impose a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad conforms to the non-uniform shape to distribute the force over the surface area and reduce discomfort in the patient.

19. The apparatus as defined in claim 18 wherein the gel pad comprises an adherent surface that assists in positioning the biological tissue between the first and second compression surfaces.

20. The apparatus as defined in claim 14 wherein the ultrasonic transducer comprises a multiplicity of piezoelectric transducer elements.

21. The apparatus as defined in claim 20 wherein the control circuitry further comprises circuitry for activating predetermined ones of the multiplicity of piezoelectric transducer elements to provide beam forming and elevational focussing of the acoustic energy.

22. The apparatus as defined in claim 20 wherein the control circuitry comprises circuitry for activating a predetermined plurality of the multiplicity of piezoelectric elements to generate an ultrasonic image at a predetermined location, the apparatus further comprising:

a biopsy instrument support;

means for aligning the biopsy instrument support with the predetermined plurality of piezoelectric elements so that a medical practitioner may perform a biopsy guided by the ultrasonic image at the predetermined location.

23. In apparatus for obtaining images of a biological tissue having a shape by passing X-ray radiation through a biological tissue to form an image in a receptor, the biological tissue having an X-ray attenuation characteristic, the apparatus comprising an X-ray source for emitting X-ray radiation, first and second compression surfaces adapted for immobilizing the biological tissue therebetween so that the biological tissue has a portion of uniform thickness and a peripheral portion of non-uniform thickness, and a receptor disposed adjacent the second compression surface, the X-ray source disposed adjacent the first compression surface so that X-ray radiation emitted from the source passes through the biological tissue and is received by the receptor, the improvement comprising:

an ultrasonic transducer disposed between the first and second compression surfaces;

a gel pad disposed between the first and second compression surfaces and in contact with the biological tissue, the gel pad acoustically coupling a portion of the biological tissue to the ultrasonic transducer, comprising a material that conforms to the shape of the biological tissue and having an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue, the gel pad enhancing the image of the peripheral portion formed in the receptor; and

gantry means for moving the ultrasonic transducer along a curved path between the first and second compression surfaces while the biological tissue remains immobilized therebetween.

24. The apparatus as defined in claim 23 wherein the gel pad reduces scattering of the X-ray radiation relative to scattering of the X-ray radiation in air.

25. The apparatus as defined in claim 23 wherein the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the first and second compression surfaces impose a force on the biological tissue, and the gel pad conforms to the non-uniform shape to distribute the force over the surface area and reduce discomfort in the patient.

26. The apparatus as defined in claim 25 wherein the gel pad comprises an adherent surface that assists in positioning the biological tissue between the first and second compression surfaces.

27. Apparatus for generating a plurality of ultrasound images of a biological tissue, the apparatus for use with an X-ray system that forms an image of the biological tissue in a receptor, the apparatus comprising:

a compression plate that is radiolucent and sonolucent, the compression plate having first and second surfaces, the first surface forming a compression surface against which the biological tissue is immobilized;

an ultrasonic transducer disposed adjacent the second surface; and

drive means for moving the ultrasonic transducer across the second surface while the biological tissue remains immobilized against the compression surface.

28. The apparatus as defined in claim 27 wherein the compression plate comprises a material selected for a group consisting of Kapton®

, a Surlyn®

ionomer, and a polymethyl pentene.

29. The apparatus as defined in claim 28 wherein the polymethyl pentene is TPX®

.

30. The apparatus as defined in claim 28 wherein the material has a periphery and the material is coupled around the periphery to a rigid frame.

31. The apparatus as defined in claim 27 further comprising a gel pad for acoustically coupling a portion of the biological tissue to the ultrasonic transducer.

32. The apparatus as defined in claim 31 wherein the biological tissue has an X-ray attenuation characteristic, the gel pad is disposed against the compression surface and in contact with the biological tissue, and comprises a material that conforms to the shape of the biological tissue and has an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue.

33. The apparatus as defined in claim 32 wherein the gel pad reduces scattering of the X-ray radiation relative to scattering of the X-ray radiation in air.

34. The apparatus as defined in claim 31 wherein the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the compression plate imposes a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad conforms to the non-uniform shape to distribute the force over the surface area and reduce discomfort in the patient.

35. The apparatus as defined in claim 34 wherein the gel pad comprises an adherent surface that assists in positioning the biological tissue relative to the compression surface.

36. The apparatus as defined in claim 27 further comprising lubricating means for providing a film of fluid between the ultrasonic transducer and the compression plate to lubricate and acoustically couple the ultrasonic transducer and the compression plate.

37. The apparatus as defined in claim 27 wherein the drive means further comprises:

a gantry support;

a gantry movably engaged with the gantry support for movement in the distal and proximal directions;

a carriage movably engaged with the gantry for lateral movement.

38. The apparatus as defined in claim 37 wherein the drive means further comprises:

a first motorized cable arrangement for driving the gantry along the gantry support;

a second motorized cable arrangement for driving the carriage along the gantry; and

circuitry for controlling operation of the first and second motorized cable arrangements.

39. The apparatus as defined in claim 37 further comprising:

a biopsy instrument support;

means for aligning the biopsy instrument support with the ultrasonic transducer so that a medical practitioner may perform a biopsy guided by the plurality of ultrasonic images.

40. Apparatus for generating a plurality of ultrasound images of a biological tissue, the apparatus for use with an X-ray system that forms an image of the biological tissue in a receptor, the receptor, the apparatus comprising:

a compression surface against which the biological tissue is immobilized, the compression surface being radiolucent;

an ultrasonic transducer disposed adjacent the compression surface;

a coupling medium interposed between the ultrasonic transducer and the compression surface; and

control circuitry for activating the ultrasonic transducer to generate a plurality of ultrasound images of the biological tissue while the biological tissue remains immobilized against the compression surface.

41. The apparatus as defined in claim 40 further comprising a gel pad for acoustically coupling a portion of the biological tissue to the ultrasonic transducer.

42. The apparatus as defined in claim 41 wherein the biological tissue has an X-ray attenuation characteristic, the gel pad is disposed against the compression surface and in contact with the biological tissue, and the gel pad comprises a material that conforms to the shape of the biological tissue and has an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue.

43. The apparatus as defined in claim 42 wherein the gel pad reduces scattering of the X-ray radiation relative to scattering of the X-ray radiation in air.

44. The apparatus as defined in claim 41 wherein the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the compression surface imposes a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad conforms to the non-uniform shape to distribute the force over the surface area and reduce discomfort in the patient.

45. The apparatus as defined in claim 44 wherein the gel pad comprises an adherent surface that assists in positioning the biological tissue relative to the compression surface.

46. The apparatus as defined in claim 41 wherein the ultrasonic transducer comprises a multiplicity of piezoelectric transducer elements.

47. The apparatus as defined in claim 48 wherein the control circuitry further comprises circuitry for activating predetermined ones of the multiplicity of piezoelectric transducer elements to provide beam forming and elevational focussing of the acoustic energy.

48. The apparatus as defined in claim 46 wherein the control circuitry comprises circuitry for activating a predetermined plurality of the multiplicity of piezoelectric elements to generate an ultrasonic image at a predetermined location, the apparatus further comprising:

a biopsy instrument support;

means for aligning the biopsy instrument support with the predetermined plurality of piezoelectric elements so that a medical practitioner may perform a biopsy guided by the ultrasonic image at the predetermined location.

49. Apparatus for generating a plurality of ultrasound images of a biological tissue, including peripheral portions, the apparatus for use with an X-ray system that forms an image of the biological tissue in a receptor, so that when the apparatus is used with the X-ray system, the plurality of ultrasound images of the biological tissue may be correlated to the image formed in the receptor, the X-ray system including first and second compression surfaces adapted for immobilizing the biological tissue therebetween so that the biological tissue has a portion of uniform thickness and a peripheral portion of non-uniform thickness, the biological tissue having an X-ray attenuation characteristic the apparatus comprising:

an ultrasonic transducer disposed between the first and second compression surfaces;

a gel pad disposed between the first and second compression surfaces and in contact with the biological tissue, the gel pad acoustically coupling a portion of the biological tissue to the ultrasonic transducer, comprising a material that conforms to the shape of the biological tissue and having an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue, the gel pad enhancing the image of the peripheral portion formed in the receptor; and

gantry means for moving the ultrasonic transducer along a curved path between the first and second compression surfaces while the biological tissue remains immobilized therebetween, so that the ultrasonic transducer generates a plurality of ultrasound images of the biological tissue that may be correlated to the image formed in the receptor.

50. The apparatus as defined in claim 49 wherein the gel pad reduces scattering of the X-ray radiation relative to scattering of the X-ray radiation in air.

51. The apparatus as defined in claim 49 wherein the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the first and second compression surfaces impose a force on the biological tissue, and the gel pad conforms to the non-uniform shape to distribute the force over the surface area and reduce discomfort in the patient.

52. The apparatus as defined in claim 51 wherein the gel pad comprises an adherent surface that assists in positioning the biological tissue between the first and second compression surfaces.

53. A method of obtaining an X-ray image of a biological tissue and an ultrasound image of the biological tissue that may be correlated to the X-ray image, comprising a series of steps of:

(a) immobilizing the biological tissue with respect to a reference point using a compression plate that is radiolucent and sonolucent;

(b) exposing the biological tissue to X-ray radiation to generate an X-ray image of the biological tissue in a receptor;

(c) acoustically coupling an ultrasound transducer to the compression plate to generate a plurality of ultrasound images of the biological tissue without intervening movement of the biological tissue with respect to the reference point; and

(d) displaying any one of the plurality of ultrasound images corresponding to a predetermined location on the X-ray image.

54. The method as defined in claim 53 wherein step (b) is performed after step (c).

55. The method as defined in claim 53 further comprising steps of:

(e) repeatedly generating and displaying a plurality of ultrasound images on a timewise basis;

(f) inserting a biopsy instrument into the biological tissue so that a portion of the biopsy instrument is visible in the plurality of ultrasound images; and

(g) maneuvering the biopsy instrument to a desired location within the biological tissue based on the X-ray image and the plurality of ultrasound images.

56. The method as defined in claim 53 further comprising steps of:

(e) storing the plurality of ultrasound images in a storage medium; and

(f) retrieving any one of the plurality of ultrasound images from the storage medium corresponding to a predetermined location on the X-ray image.

57. The method as defined in claim 53 further comprising a step of processing the plurality of ultrasound images to enhance the diagnostic capabilities of those images.

58. The method as defined in claim 53 further comprising steps of:

(e) repeatedly generating and displaying a plurality of ultrasound images on a timewise basis at a location within the biological tissue;

(f) processing the plurality of ultrasound images at the location to provide an indicator corresponding to blood flow at that location.

59. The method as defined in claim 53 further comprising steps of:

(e) generating a plurality of Doppler signals for the biological tissue by acoustically coupling an ultrasonic transducer to the biological tissue, without intervening movement of the biological tissue with respect to the reference point; and

(f) displaying an indicator corresponding to the plurality of Doppler signals for a predetermined location on the X-ray image.

60. The method as defined in claim 53 further comprising a series of steps of:

(e) storing the plurality of ultrasound images in a storage medium; and

(f) displaying selected ones of the plurality of ultrasound images to provide a holographic view of the interior features of the biological tissue.

61. The method as defined in claim 53 wherein the compression plate lies in an X-Y plane and each one of the ultrasound images comprises a multiplicity of digitally encoded data values obtained at a multiplicity of planes along a Z axis orthogonal to the X-Y plane, the method further comprising the steps of:

(e) summing the multiplicity of digitally encoded data values along the Z axis to generate a projection of the plurality of ultrasound images into the X-Y plane; and

(f) displaying the projection.

62. The method as defined in claim 61 further comprising a step of comparing the X-ray image to the projection to isolate selected ones of the interior features of the biological tissue.

63. The method as defined in claim 62 wherein the X-ray image and the projection are color coded.

64. The method as defined in claim 62 wherein step (a) is performed after step (c).

65. A method of screening a biological tissue for abnormalities, comprising a series of steps of:

(a) immobilizing the biological tissue with respect to a reference point using a compression plate that is radiolucent and sonolucent;

(b) exposing the biological tissue to X-ray radiation to generate an X-ray image of the biological tissue in a receptor;

(c) applying a first compressive load to the biological tissue;

(d) acoustically coupling an ultrasound transducer to the compression plate to generate a first plurality of digitally encoded ultrasound images of the biological tissue with respect to the reference point;

(e) storing the first plurality of digitally encoded ultrasound images;

(f) applying a second compressive load to the biological tissue, the second compressive load different than the first compressive load;

(g) operating the ultrasound transducer to generate a second plurality of digitally encoded ultrasound images of the biological tissue with respect to the reference point;

(h) digitally subtracting each one of the second plurality of digitally encoded ultrasound images from a corresponding one of the first plurality of digitally encoded ultrasound images with respect to the reference point;

(i) displaying the difference of first and second digitally encoded ultrasound images; and

(j) comparing the difference of the first and second digitally encoded ultrasound images at a predetermined location to a corresponding location on the X-ray image.

66. The method as defined in claim 65 wherein the first and second pluralities of digitally encoded ultrasound image are color coded.