Method and system for monitoring ablation of tissues

• US 8,603,015 B2
• Filed: 10/06/2011
• Issued: 12/10/2013
• Est. Priority Date: 12/13/2004
• Status: Active Grant

• Current Assignee: Tel Hashomer Medical Research Infrastructure And Services Ltd.
• Original Assignee: Tel Hashomer Medical Research Infrastructure And Services Ltd.
• Inventors: Rosemberg, Yossef, Orenstein, Arie
• Primary Examiner(s): Lamprecht, Joel
• Application Number:
  US13/267,232
• Publication Number:
  US 20120029497A1
• Time in Patent Office: 796 Days
• Field of Search: 600/407, 600/437, 600/439, 600/443, 600/447, 601 2- 4
• US Class Current: 601/3
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 8/0833 involving detecting or locating foreign bodies or organic structures
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

A method of monitoring heat damage to a tissue during a heat ablation procedure is disclosed. The method comprising: providing images of the tissue, extracting at least one parameter being indicative of a biological response to heat, and using the parameter(s) for determining the heat damage to the tissue.

Claims

1. A method of monitoring heat damage to a volume of tissue during a heat ablation procedure, the method comprising:

employing an imaging device to obtain real-time images of a volume of tissue in an area undergoing said heat ablation procedure at an imaging rate;

employing a processor to carry out the steps of;

for each pixel in each of said real time images, extracting at least one parameter indicative of a biological response to heat in a portion of said tissue imaged in said pixel, said biological response comprising a decrement in blood circulation viability; and

for each said pixel in each of said real time images, using an electronic calculation functionality, algorithmically determining based on said at least one parameter whether damage-onset has occurred in said portion of said tissue imaged in said pixel following exposure to heat in said heat ablation procedure; and

displaying a differentiation image corresponding to each of said real-time images, such that in said differentiation image, pixels corresponding to tissue damaged by said heat ablation procedure appear different from pixels corresponding to viable tissue.

2. The method of claim 1, wherein said images are selected from a group consisting of non-Doppler ultrasound images, magnetic resonance images, X-ray images and gamma images.

3. The method of claim 1, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be when said decrement in said blood circulation viability is above a predetermined threshold.

4. The method of claim 1, wherein said biological response comprises accumulation of bubbles near the tissue, while the heat ablation is at a substantially constant rate.

5. The method of claim 4, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be when an increment in the density of said bubbles near the tissue is above a predetermined threshold.

6. The method of claim 1, wherein said biological response comprises disappearance of bubbles along a non-random pattern, while the heat ablation is at a substantially constant rate.

7. The method of claim 6, further comprising determining that said portion of said tissue imaged in said pixel is viable if said disappearance of said bubbles along said non-random pattern occurs.

8. The method of claim 6, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be when a rate of said disappearance of said bubbles along said non-random pattern is below a predetermined threshold.

9. The method of claim 2, wherein said at least one parameter is a non-Doppler ultrasound parameter comprising echogenicity variations and said determining whether damage-onset has occurred comprises defining at least one damage criterion based on said echogenicity variations, and defining damage-onset to be when said at least one damage criterion is met.

10. The method of claim 9, wherein said at least one damage criterion comprises a substantial abrupt rise in echogenicity of said portion of said tissue over a predetermined time-period.

11. The method of claim 9, wherein said at least one damage criterion comprises a moderate decrease in echogenicity of said portion of said tissue over a predetermined time-period while the heat ablation is at least temporarily ceased.

12. The method of claim 9, wherein said at least one damage criterion comprises a rise in echogenicity of said portion of said tissue while the heat ablation is at a substantial constant rate, which rise can be fitted to an exponential function.

13. The method of claim 9, wherein said real time images comprise non-Doppler ultrasound images and wherein said at least one damage criterion comprises a random echogenicity gradient, corresponding to random spatial distribution of bubble disappearance, over a region of a non-Doppler ultrasound image while the heating is at least temporarily ceased.

14. A method of destructing a target tissue, the method comprising:

delivering energy at a predetermined rate so as to heat the target tissue;

executing the method of claim 1 to determine whether tissue neighboring said target tissue has been damaged; and

if said neighboring tissue has been damaged, ceasing said delivery of said energy.

15. The method of claim 6, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be said disappearance of said bubbles is in a random pattern.

16. A method of monitoring heat damage to a volume of tissue during a heat ablation procedure, the method comprising:

employing an imaging device to obtain real-time images of a volume of tissue in an area undergoing said heat ablation procedure at an imaging rate;

employing a processor to carry out the steps of;

for each pixel in each of said real time images, extracting at least one parameter indicative of a biological response to heat in a portion of said tissue imaged in said pixel, said biological response comprising accumulation of bubbles near said tissue, while the heat ablation is at a substantially constant rate; and

for each said pixel in each of said real time images, using an electronic calculation functionality, algorithmically determining based on said at least one parameter whether damage-onset has occurred in said portion of said tissue imaged in said pixel following exposure to heat in said heat ablation procedure; and

displaying a differentiation image corresponding to each of said real-time images, such that in said differentiation image, pixels corresponding to tissue damaged by said heat ablation procedure appear different from pixels corresponding to viable tissue.

17. The method of claim 16, wherein said images are selected from a group consisting of non-Doppler ultrasound images, magnetic resonance images, X-ray images and gamma images.

18. The method of claim 16, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be when an increment in the density of said bubbles near the tissue is above a predetermined threshold.

19. The method of claim 16, wherein said biological response comprises disappearance of bubbles along a non-random pattern, while the heat ablation is at a substantially constant rate.

20. The method of claim 19, further comprising determining that said portion of said tissue imaged in said pixel is viable if said disappearance of said bubbles along said non-random pattern occurs.

21. The method of claim 19, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be when a rate of said disappearance of said bubbles along said non-random pattern is below a predetermined threshold.

22. The method of claim 17, wherein said at least one parameter is a non-Doppler ultrasound parameter comprising echogenicity variations and said determining whether damage-onset has occurred comprises defining at least one damage criterion based on said echogenicity variations, and defining damage-onset to be when said at least one damage criterion is met.

23. The method of claim 22, wherein said at least one damage criterion comprises a substantial abrupt rise in echogenicity of said portion of said tissue over a predetermined time-period.

24. The method of claim 22, wherein said at least one damage criterion comprises a moderate decrease in echogenicity of said portion of said tissue over a predetermined time-period while the heat ablation is at least temporarily ceased.

25. The method of claim 22, wherein said at least one damage criterion comprises a rise in echogenicity of said portion of said tissue while the heat ablation is at a substantial constant rate, which rise can be fitted to an exponential function.

26. The method of claim 22, wherein said real time images comprise non-Doppler ultrasound images and wherein said at least one damage criterion comprises a random echogenicity gradient, corresponding to random spatial distribution of bubble disappearance, over a region of a non-Doppler ultrasound image while the heating is at least temporarily ceased.

27. A method of destructing a target tissue, the method comprising:

delivering energy at a predetermined rate so as to heat the target tissue;

executing the method of claim 16 to determine whether tissue neighboring said target tissue has been damaged; and

if said neighboring tissue has been damaged, ceasing said delivery of said energy.

28. The method of claim 19, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be said disappearance of said bubbles is in a random pattern.

29. A method of monitoring heat damage to a volume of tissue during a heat ablation procedure, the method comprising:

employing an imaging device to obtain real-time images of a volume of tissue in an area undergoing said heat ablation procedure at an imaging rate;

employing a processor to carry out the steps of;

for each pixel in each of said real time images, extracting at least one parameter indicative of a biological response to heat in a portion of said tissue imaged in said pixel, said biological response comprising disappearance of bubbles along a non-random pattern, while the heat ablation is at a substantially constant rate; and

for each said pixel in each of said real time images, using an electronic calculation functionality, algorithmically determining based on said at least one parameter whether damage-onset has occurred in said portion of said tissue imaged in said pixel following exposure to heat in said heat ablation procedure; and

displaying a differentiation image corresponding to each of said real-time images, such that in said differentiation image, pixels corresponding to tissue damaged by said heat ablation procedure appear different from pixels corresponding to viable tissue.

30. The method of claim 29, wherein said images are selected from a group consisting of non-Doppler ultrasound images, magnetic resonance images, X-ray images and gamma images.

31. The method of claim 29, further comprising determining that said portion of said tissue imaged in said pixel is viable if said disappearance of said bubbles along said non-random pattern occurs.

32. The method of claim 29, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be when a rate of said disappearance of said bubbles along said non-random pattern is below a predetermined threshold.

33. The method of claim 30, wherein said at least one parameter is a non-Doppler ultrasound parameter comprising echogenicity variations and said determining whether damage-onset has occurred comprises defining at least one damage criterion based on said echogenicity variations, and defining damage-onset to be when said at least one damage criterion is met.

34. The method of claim 33, wherein said at least one damage criterion comprises a substantial abrupt rise in echogenicity of said portion of said tissue over a predetermined time-period.

35. The method of claim 33, wherein said at least one damage criterion comprises a moderate decrease in echogenicity of said portion of said tissue over a predetermined time-period while the heat ablation is at least temporarily ceased.

36. The method of claim 33, wherein said at least one damage criterion comprises a rise in echogenicity of said portion of said tissue while the heat ablation is at a substantial constant rate, which rise can be fitted to an exponential function.

37. The method of claim 33, wherein said real time images comprise non-Doppler ultrasound images and wherein said at least one damage criterion comprises a random echogenicity gradient, corresponding to random spatial distribution of bubble disappearance, over a region of a non-Doppler ultrasound image while the heating is at least temporarily ceased.

38. A method of destructing a target tissue, the method comprising:

delivering energy at a predetermined rate so as to heat the target tissue;

executing the method of claim 29 to determine whether tissue neighboring said target tissue has been damaged; and

if said neighboring tissue has been damaged, ceasing said delivery of said energy.

39. The method of claim 29, wherein said determining whether damage-onset has occurred comprises defining damage-onset to be said disappearance of said bubbles is in a random pattern.