Optical measurement of tissue blood flow, hemodynamics and oxygenation

• US 20060063995A1
• Filed: 04/13/2005
• Published: 03/23/2006
• Est. Priority Date: 04/13/2004
• Status: Active Grant

• Current Assignee: Trustees Of The University Of Pennsylvania (University of Pennsylvania)
• Original Assignee: Trustees Of The University Of Pennsylvania (University of Pennsylvania)
• Inventors: Yodh, Arjun G., Detre, John A., Durduran, Turgut, Quon, Harry, Greenberg, Joel H., Hahn, Stephen M., Burnett, Mark G., Yu, Guoqiang, Mohler, Emile R. III
• Granted Patent: US 8,082,015 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence

Abstract

An embodiment of the invention includes a device, system and method for determining the characteristics of deep tissue. The novel method includes measuring blood flow rate and oxygenation characteristics of the tissue, and determining oxygen metabolism of the tissue as a function of the measure blood flow rate and measure oxygenation. The blow flow rate characteristics are measured as a function of light fluctuations caused by the tissue, while the oxygenation characteristics are measured as a function of transmission of light through the tissue with respect to the wavelength of light. The tissue may be layered tissue, for example, a portion of a brain. The tissue characteristics may be measured during times of varying levels of exercise intensity.

Claims

1. A method for determining the characteristics of tissue, comprising:

measuring blood flow rate characteristics of the tissue, wherein the blood flow rate characteristics are derived from light fluctuations caused by the tissue;

measuring blood oxygenation, oxy and deoxy-hemoglobin, hemodynamic, and scattering characteristics of the tissue, wherein the blood oxygenation, oxy and deoxy-hemoglobin, hemodynamic, and scattering characteristics are derived from transmission of light through the tissue with respect to the wavelength of light; and

determining oxygen metabolism of the tissue and changes of the tissue from the measured blood flow rate and from the measure hemodynamic and oxygenation.

2. The method of claim 1, wherein the blood oxygenation and hemoglobin characteristics are further derived as a function of a position of a source detector.

3. The method of claim 1, wherein the tissue is a portion of at least one of the following:

brain, muscle, breast.

4. The method of claim 1, wherein the tissue is a portion of a tumor bearing organ including at least one of the following:

head, neck, prostate, breast, and brain.

5. The method of claim 1, wherein the tissue is at least one of the following:

layered and heterogenous.

6. The method of claim 1, wherein the tissue characteristics are measured during exercise.

7. The method of claim 1, wherein the tissue characteristics are measured during functional activation.

8. The method of claim 1, wherein the tissue characteristics are measured during a presence of tissue damage due to stroke.

9. The method of claim 1, wherein the tissue characteristics are measured during a presence of tissue damage due to trauma.

10. The method of claim 1, wherein the tissue characteristics are measured during a presence of tissue damage due to cardiovascular disease.

11. The method of claim 1, further comprising measuring an autocorrelation of the transmitted light with respect to a delay time to determine a decay rate of an autocorrelation function.

12. The method of claim 11, further comprising determining an extent of the movement of a blood cell in the tissue.

13. The method of claim 11, further comprising determining the velocity of the movement of a blood cell in the tissue.

14. The method of claim 11, further comprising determining a motion of cell organelles in the tissue.

15. The method of claim 11, further comprising determining fluctuations of cell organelles in the tissue.

16. The method of claim 1, wherein the blood flow rate and the oxygenation are measured substantially simultaneously.

17. The method of claim 1, further comprising monitoring peripheral vascular disease.

18. The method of claim 1, further comprising monitoring therapeutic interventions to cancers in organs.

19. The method of claim 1, further comprising monitoring effects of cardiovascular disease on muscles.

20. The method of claim 1, further comprising monitoring effects of cerebrovascular disease on brain well-being and function.

21. The method of claim 1, further comprising determining an efficacy of exercise rehabilitation.

22. The method of claim 1, further comprising determining an efficacy of cancer therapy.

23. The method of claim 1, further comprising determining an efficacy of tumor treatment and therapy.

24. The method of claim 1, further comprising monitoring peripheral vascular disease.

25. The method of claim 1, further comprising determining efficacy of a drug used to facilitate blood flow.

26. The method of claim 1, further comprising determining efficacy of a drug used to treat cancers during photodynamic therapy.

27. The method of claim 1, wherein the tissue is human.

28. The method of claim 1, wherein the tissue is animal.

29. The method of claim 1, wherein the measurements are taken without a probe penetrating scalp and skull of the brain.

30. The method of claim 1, wherein the measurements are taken non-invasively.

31. A device for determining the characteristics of deep tissue, comprising:

a light source for applying light to the tissue;

a light detector for detecting the quantity of light transmitted through the tissue; and

a computer processor in communication with the light detector, wherein the computer processor determines changes in oxy . . . from changes in the transmitted light and light fluctuations as a function of wavelength to determine blood oxygenation.

32. The device of claim 31, wherein the light source is a laser.

33. The device of claim 31, wherein the light source is a stable light source.

34. The device of claim 31, further comprising optical switches to share source positions.

35. The device of claim 31, further comprising electrical switches to share detectors.

36. The device of claim 31, further comprising at least one of the following:

photodiodes, avalanche photodiodes, photomultiplier tubes, and CCD camera.

37. The device of claim 31, further comprising another laser source to measure blood flow in more than one wavelength.

38. The device of claim 31, wherein a fast CCD camera or photomultiplier is used as a detector.

39. The device of claim 31, further comprising a computer having a computer-readable medium with computer-executable instructions, wherein the computer-executable instructions calculate a correlation function.

40. The device of claim 31, further comprising a component to measure flow of externally injected microspheres through vasculature.

41. The device of claim 31, further comprising at least one other light detector.

42. The device of claim 31, wherein the device measures at least one of the following:

blood oxygenation, oxy and deoxy-hemoglobin, hemodynamic, and scattering.

43. The device of claim 31, wherein the device determines oxygen metabolism.

44. The device of claim 31, wherein oxygen metabolism is measured using at bulk overall value technique.

45. The device of claim 31, wherein oxygen metabolism is measured at one or more locations.

46. The device of claim 31, wherein oxygen metabolism is measured as two dimensional imagers.

47. The device of claim 31, wherein oxygen metabolism is measured as three dimensional imagers.