System and method for determining a hydration level of a tissue region

• US 9,999,352 B2
• Filed: 09/27/2013
• Issued: 06/19/2018
• Est. Priority Date: 09/27/2013
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Sabatini, James Enrico, Ashe, Jeffrey Michael, Chen, Xiaohui, Kao, Tzu-Jen
• Primary Examiner(s): Cheng, Jacqueline
• Assistant Examiner(s): PORTILLO, JAIRO H
• Application Number:
  US14/039,497
• Publication Number:
  US 20150094548A1
• Time in Patent Office: 1,726 Days
• Field of Search: None
• CPC Class Codes: A61B 5/0053 by applying pressure, e.g. compression, indentation, palpation, grasping, gauging
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/4875 Hydration status, fluid retention of the body
• CPC Class Codes: A61B 5/4878 Evaluating oedema

Abstract

In accordance with one aspect of the present technique, a method is disclosed. The method includes applying a mechanical perturbation to a tissue region using a displacement device. The method further includes calculating a compression impedance of the tissue region in response to applying the mechanical perturbation. The method further includes retracting the displacement device and calculating a retraction impedance of the tissue region in response to retracting the displacement device. The method also includes determining a hydration level of the tissue region based on at least one of the compression impedance and the retraction impedances.

Claims

1. A method comprising:

applying an electric current, via a plurality of electrodes disposed on top of a tissue region, to the tissue region and measuring an electric voltage across the tissue region generated due to the electric current;

applying an indentation to the tissue region using a displacement device positioned such that the indentation is solely applied in-between the plurality of electrodes;

calculating, by an impedance module, a compression impedance (CI) of the tissue region in response to applying the indentation based on the applied electric current and the measured electric voltage;

retracting the displacement device;

calculating, by the impedance module, a retraction impedance (RI) of the tissue region in response to retracting the displacement device based on the applied electric current and the measured electric voltage;

determining, by the impedance module, at least one of a change in the CI and a change in the RI based on a stabilization threshold range, the CI, and the RI; and

determining, by a staging module, a hydration level of the tissue region based at least on one of the change in the CI and the change in the RI.

2. The method of claim 1, wherein the hydration level includes at least one of an edema stage and a dehydration stage of the tissue region.

3. The method of claim 1, further comprising applying the indentation to the tissue region based on at least one of a pre-determined force and a pre-determined displacement of the tissue region.

4. The method of claim 1, further comprising:

calculating a rate of change of the CI and a rate of change of the RI based on at least one of a linear function, a quadratic function, and an exponential function; and

determining the hydration level of the tissue region based on at least one of the rate of change of the CI and the rate of change of the RI, wherein the rate of change of the CI and the rate of change of the RI correspond to application of the indentation, and retraction of the displacement device from the tissue region respectively.

5. The method of claim 4, wherein determining at least one of the change in the CI and the change in the RI comprises:

determining whether the rate of change of the CI is within the stabilization threshold range;

calculating the change in the CI in response to determining that the rate of change of the CI is within the stabilization threshold range; and

determining the hydration level of the tissue region based on the change in the CI, wherein the change in the CI is a difference between a baseline impedance and a steady state CI.

6. The method of claim 5, further comprising:

calculating a compression duration in response to determining that the rate of change of the CI is within the stabilization threshold range; and

determining the hydration level of the tissue region based on the compression duration.

7. The method of claim 5, wherein the change in the CI further comprises a slow CI change and a fast CI change, and wherein the slow CI change is caused due to compression of fluid in the tissue region and the first CI change is caused due to compression of skin in the tissue region.

8. The method of claim 5, further comprising retracting the displacement device in response to determining that the rate of change of the CI is within the stabilization threshold range.

9. The method of claim 8, wherein determining at least one of the change in the CI and the change in the RI comprises:

determining whether the rate of change of the RI is within the stabilization threshold range;

calculating the change in the RI in response to determining that the rate of change of the RI is within the stabilization threshold range; and

determining the hydration level of the tissue region based on the change in the RI, wherein the change in the RI is a difference between the steady state CI and a steady state RI.

10. The method, of claim 9, further comprising:

calculating a retraction duration in response to determining that the rate of change of the RI is within the stabilization threshold range; and

determining the hydration level of the tissue region based on the retraction duration.

11. The method of claim 9, wherein the change in the RI further comprises a slow RI change and a fast RI change, and wherein the slow RI change is caused due to expansion of fluid in the tissue region and the fast RI change is caused due to expansion of skin in the tissue region.

12. A system comprising:

at least one processor;

a plurality of electrodes disposed on top of a tissue region configured to apply an electric current to the tissue region and measure an electric voltage across the tissue region generated due to the electric current;

a displacement module stored in a memory and executable by the at least one processor, the displacement module for applying an indentation to the tissue region using a displacement device positioned such that the indentation is solely applied in-between the plurality of electrodes and retracting the displacement device;

an impedance module stored in the memory and executable by the at least one processor, the impedance module communicatively coupled to the displacement module for calculating a compression impedance (CI) of the tissue region in response to applying the indentation based on the applied electric current and the measured electric voltage, calculating a retraction impedance (RI) of the tissue region in response to retracting the displacement device based on the applied electric current and the measured electric voltage, and determining at least one of a change in the CI and a change in the RI based on a stabilization threshold range, the CI, and the RI; and

, a staging module stored in the memory and executable by the at least one processor, the staging module communicatively coupled to the impedance module for determining a hydration level of the tissue region based at least on one of the change in the CI and the change in the RI.

13. The system of claim 12, wherein the hydration level includes at least one of an edema stage and a dehydration stage of the tissue region.

14. The system of claim 12, wherein the impedance module further calculates a rate of change of the CI and a rate of change of the RI based on at least one of a linear function, a quadratic function, and an exponential function, and wherein the rate of change of the CI and the rate of change of the RI correspond to application of the indentation, and retraction of the displacement device from the tissue region respectively.

15. The system of claim 14, wherein the impedance module further determines whether the rate of change of the CI is within the stabilization threshold range, calculates the change in the CI in response to determining that the rate of change of the CI is within the stabilization threshold range, determines whether the rate of change of RI is within the stabilization threshold range, and calculates a change in RI in response to determining that the rate of change of the RI is within the stabilization threshold range, wherein the change in the CI is a difference between a baseline impedance and a steady state CI, and wherein the change in the RI is a difference between the steady state CI and a steady state RI.

16. The system of claim 15, wherein the change in the CI comprises a slow CI change and a fast CI change and the change in the RI includes a slow RI change and a Bast RI change, wherein the slow CI change is caused due to compression of fluid in the tissue region, and the fast CI change is caused due to compression of skin in the tissue region, and wherein the slow RI change is caused due to, expansion of fluid in the tissue region and the fast RI change is caused due to expansion of skin in the tissue region.

17. The system of claim 15, wherein the displacement module retracts the displacement device in response to determining that the rate of change of the CI is within the stabilization threshold range.

18. The system of claim 15, further comprising a timing module for calculating a compression duration in response to determining that the rate of change of the CI is within the stabilization threshold range and calculating a retraction duration in response to determining that the rate of change of the RI is within the stabilization threshold range.

19. The system of claim 15, wherein the staging module further determines the hydration level based on at least one of the rate of change of the CI, the rate of change of the RI, the change in the CI, or the change in the RI.

20. A computer program product comprising a non-transitory computer readable medium encoding instructions that, in response to execution by at least one processor, cause the processor to perform operations comprising:

applying an electric current, via a plurality of electrodes disposed on top, of a tissue region, to the tissue region and measuring an electric voltage across the tissue region generated due to the electric current;

applying an indentation to the tissue region using a displacement device positioned such that the indentation is solely applied in-between the plurality of electrodes;

calculating, by an impedance module, a compression impedance (CI) of the tissue region in response to applying the indentation based on the applied electric current and the measured electric voltage;

retracting the displacement device;

calculating, by the impedance module, a retraction impedance (RI) of the tissue region in response to retracting the displacement device based on the applied electric current and the measured electric voltage;

determining, by the impedance module, at least one of a change in the CI and a change in, the RI based on a stabilization threshold range, the CI and the RI; and

determining, by a staging module, a hydration level of the tissue region based on at least one of the change in the CI and the change in the RI.