DEVICES AND METHODS FOR EVALUATING TISSUE

• US 20140039341A1
• Filed: 04/27/2012
• Published: 02/06/2014
• Est. Priority Date: 04/28/2011
• Status: Active Grant

• Current Assignee: Skulpt, Inc.
• Original Assignee: Skulpt, Inc.
• Inventors: Avestruz, Al-Thaddeus, Lupton, Elmer C., Bohorquez, Jose L., Rinehart, Michael D., Rutkove, Seward
• Granted Patent: US 8,892,198 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 2017/0023 disposable
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• CPC Class Codes: A61B 2560/0431 Portable apparatus, e.g. comprising a handle or case
• CPC Class Codes: A61B 2560/0443 Modular apparatus
• CPC Class Codes: A61B 2560/0468 Built-in electrodes
• CPC Class Codes: A61B 2562/0223 Magnetic field sensors
• CPC Class Codes: A61B 2562/04 Arrangements of multiple sensors of the same type
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/14 Coupling media or elements to improve sensor contact with skin or tissue
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• CPC Class Codes: A61B 2562/166 the sensor is mounted on a specially adapted printed circuit board
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence
• CPC Class Codes: A61B 5/6832 using adhesives A61B5/259 takes precedence
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/684 Indicating the position of the sensor on the body
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7225 : Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7228 : Signal modulation applied to the input signal sent to patient or subject; demodulation to recover the physiological signal modulation H03C
• CPC Class Codes: A61B 5/7235 : Details of waveform analysis A61B5/349 takes precedence
• CPC Class Codes: A61B 5/7278 : Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7405 : using sound
• CPC Class Codes: A61B 5/742 : using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7475 : User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: F04C 2270/041 : Controlled or regulated

Abstract

Embodiments of devices and methods for evaluating tissue are disclosed. In one embodiment, a method for measuring a characteristic of a tissue may include passing a current through the tissue, measuring a signal corresponding to the voltage resulting from passing the current through the tissue, analyzing current passed through the tissue and resulting voltage to determine the electrical characteristics of the tissue; and analyzing the electrical characteristics of the tissue to determine a status of the tissue.

Claims

1. A method for measuring a characteristic of a tissue, comprising:

passing a current through the tissue;

measuring a signal corresponding to the voltage resulting from passing the current through the tissue;

analyzing current passed through the tissue and resulting voltage to determine the electrical characteristics of the tissue; and

analyzing the electrical characteristics of the tissue to determine a status of the tissue.

3. The method of claim 1, wherein the tissue includes living human tissue.

4. The method of claim 1, wherein the tissue includes muscular tissue.

5. The method of claim 1, wherein the current includes alternating current.

6. The method of claim 1, wherein the frequency of the alternating current is between 1 kHz and 10 MHz.

7. The method of claim 1, wherein analyzing the current passed through the tissue is performed by a device comprising an amplifier.

9. The method of claim 1, wherein the signal to noise ratio of the measured signal is enhanced by a device comprising premeasurement drive equalization.

10. The method of claim 1, wherein the direction of measuring the signal is not collinear with the direction along which the current is passed.

11. The method of claim 10, wherein the direction of measurement of the signal is between 60 degrees and 120 degrees rotated from the direction along which the current is passed.

12. The method of claim 11, wherein the direction of measurement of the voltage is between 85 degrees and 95 degrees rotated from the direction along which the current is passed.

13. The method of claim 7, wherein the device includes a plurality of lock-in amplifiers operating in parallel.

14. The method of claim 1, further comprising measuring and calculating LBTI at a plurality of frequencies simultaneously.

15. The method of claim 7, further comprising verifying a calibration of the device prior to measuring the signal.

16. The method of claim 15, wherein the calibration of the device is verified automatically and the step of measuring is not permitted to proceed if the calibration cannot be verified.

17. The method claim 1, wherein the step of passing a current through tissue is performed by an electrical component having a plurality of electrode contacts configured to provide electrical contact with a surface of the tissue.

18. The method of claim 17, wherein the plurality of electrodes are contained in an electrode assembly.

28. The method of claim 1, wherein the step of analyzing the electrical characteristics of the tissue comprises the use of Cole parameters.

29. The method of claim 28, wherein the use of Cole parameters further comprises calculating a semi-ellipse to which three of the four Cole parameters are related and using that relationship to reparameterize the problem into two sequential optimizations:

a quadratic optimization that computes an optimal circle that fits the data, and a quasi-convex optimization that uses results of the optimization to find the remaining parameter.

60. The method of claim 18, wherein a spacing between two electrodes of the plurality of electrodes is about 3 inches or less.

61. The method of claim 14, wherein a first frequency of the plurality of frequencies comprises a frequency between 1 KHz and 30 kHz and a second frequency of the plurality of frequencies comprises a frequency between 150 kHz and 10 MHz.

62. The method of claim 61, wherein the plurality of frequencies includes at least four frequencies comprising about 25 kHz, about 50 kHz, about 100 kHz, and about 200 kHz.

63. The method of claim 14, wherein at least one measurement of voltage is collinear with the input current and at least one measurement of voltage is not collinear with the input current.

2. (canceled)

8. The method of claim 8, wherein the amplifier is a transimpedance amplifier.

19-27. -27. (canceled)

30. The method of claim 30, wherein the semi-ellipse comprises a semicircle.

31. A device for measuring a characteristic of a tissue, comprising:

a plurality of electrodes;

a power supply configured to be operably coupled to the plurality of electrodes to supply a signal through the tissue;

analytical electronics configured to be operably coupled to the plurality of electrodes for analyzing an input current and resulting voltage to determine the electrical characteristics of the tissue; and

electronics configured to communicate to a user a result of analysis performed by the analytical electronics.

32. The device of claim 31, wherein the signal includes controlled alternating current.

33. The device of claim 32, wherein a frequency of the alternating current is between 1 kHz and 10 MHz.

34. The device of claim 31, wherein the analytical electronics comprise a transimpedance amplifier.

35. The device of claim 31, wherein a signal to noise ratio of the measured signal is enhanced by a device comprising premeasurement drive equalization.

36. The device of claim 31, wherein at least one of the plurality of electrodes is configured to measure voltage.

37. The device of claim 36, wherein a direction of measurement of the voltage is not collinear with the direction along which the current is passed.

38. The device of claim 36, wherein a direction of measurement of the voltage is between 60 degrees and 120 degrees rotated from the direction along which the current is passed.

39. The device of claim 36, wherein a direction of measurement of the voltage is between 85 degrees and 95 degrees rotated from the direction along which the current is passed.

40. The device of claim 31, further comprising a plurality of lock-in amplifiers operating in parallel capable of simultaneous measurement and calculation of LBTI at a plurality of frequencies.

41. The device of claim 36, wherein the device is unable to measure voltage unless the device is calibrated.

42. The device of claim 41, wherein the device is configured to be calibrated automatically.

43. The device of claim 31, wherein the plurality of electrodes are contained in an electrode assembly.

44. The device of claim 31, wherein the electrode assembly is disposable and is only used for a single series of measurements.

45. The device of claim 44, further configured to determine whether the electrode assembly was previously used.

46. The device of claim 44, further comprising a mechanical mechanism for determining if the electrode assembly was previously used.

47. The device of claim 44, further comprising an electrical mechanism for determining if the electrode assembly was previously used.

48. The device of claim 47, wherein the electrical mechanism is disposed in the device.

49. The device of claim 47, wherein the electrical mechanism is remote of the device.

50. The device of claim 41, wherein the device includes at least two parts detachably secured to one another, at least one of the parts comprising the electrode assembly.

51. The device of claim 50, wherein the at least two parts are secured together by a magnet.

52. The device of claim 50, wherein the at least two parts are secured to one another by one or both of a friction or interference fit.

53. The device of claim 31, wherein the analytical electronics are configured to analyze the input current and resulting voltage with the use of Cole parameters.

54. The device of claim 53, wherein the use of Cole parameters further comprises calculating a semi-ellipse to which three of the four Cole parameters are related and using that relationship to reparameterize the problem into two sequential optimizations:

a quadratic optimization that computes an optimal ellipse that fits the data, and a quasi-convex optimization that uses results of the optimization to find the remaining parameter.

55. The device of claim 54, wherein the semi-ellipse comprises a semicircle.

56. The device of claim 43, wherein a spacing between two electrodes of the plurality of electrodes is about 3 inches or less.

57. The device of claim 40, wherein a first frequency of the plurality of frequencies comprises a frequency between 1 KHz and 30 kHz and a second frequency of the plurality of frequencies comprises a frequency between 150 kHz and 10 MHz.

58. The device of claim 57, wherein the plurality of frequencies includes at least four frequencies comprising about 25 kHz, about 50 kHz, about 100 kHz and about 200 kHz.

59. The device of claim 40, wherein at least one measurement of voltage is collinear with the input current and at least one measurement of voltage is not collinear with the input current.