FLOWOMETRY IN OPTICAL COHERENCE TOMOGRAPHY FOR ANALYTE LEVEL ESTIMATION

• US 20160058347A1
• Filed: 05/13/2015
• Published: 03/03/2016
• Est. Priority Date: 03/04/2008
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: GLT Acquisition Corporation
• Inventors: Reichgott, Samuel, Shakespeare, Walter J., Kechter, George, Wallace, Phillip William, Schurman, Matthew J.
• Granted Patent: US 10,368,787 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4875 Hydration status, fluid retention of the body
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence

Abstract

Optical coherence tomography (herein “OCT”) based analyte monitoring systems are disclosed. In one aspect, techniques are disclosed that can identify fluid flow in vivo (e.g., blood flow), which can act as a metric for gauging the extent of blood perfusion in tissue. For instance, if OCT is to be used to estimate the level of an analyte (e.g., glucose) in tissue, a measure of the extent of blood flow can potentially indicate the presence of an analyte correlating region, which would be suitable for analyte level estimation with OCT. Another aspect is related to systems and methods for scanning multiple regions. An optical beam is moved across the surface of the tissue in two distinct manners. The first can be a coarse scan, moving the beam to provide distinct scanning positions on the skin. The second can be a fine scan where the beam is applied for more detailed analysis.

Claims

1. (canceled)

2. A method comprising:

receiving, from an optical coherence tomography apparatus, an intensity data measurement for a region of tissue;

passing the intensity data measurement through a first frequency band filter having a first bandwidth to produce a first output;

passing the intensity data measurement through a second frequency band filter having a second bandwidth that is wider than the first bandwidth to produce a second output; and

determining an indication of fluid flow in the region of tissue by comparing the first output and the second output.

3. The method of claim 2, wherein both the first bandwidth and the second bandwidth are centered at a same base frequency.

4. The method of claim 2 further comprising:

in response to determining a positive indication of fluid flow in the region of tissue, determining a blood analyte measurement based on at least some the intensity data measurement.

5. The method of claim 4, wherein the blood analyte measurement comprises a measurement of at least one of:

blood glucose, blood hemoglobin, or blood oxygen.

6. The method of claim 2, wherein determining the indication of fluid flow in the region of tissue comprises:

analyzing fringe frequency data in the first output and the second output.

7. The method of claim 6, wherein analyzing fringe frequency data comprises:

analyzing frequency modulation in the fringe frequency data in the first output and the second output.

8. The method of claim 6, wherein analyzing fringe frequency data comprises:

analyzing amplitude modulation in the fringe frequency data in the first output and the second output.

9. The method of claim 8, wherein analyzing fringe frequency data further comprises:

comparing speckle intensity in the first output and the second output.

10. The method of claim 2, wherein determining the indication of fluid flow in the region of tissue comprises:

comparing speckle intensity in the first output and the second output.

11. The method of claim 2, wherein the intensity data measurement comprises a backscattered wide band signal.

12. A method comprising:

receiving, from an optical coherence tomography apparatus, intensity data measurement for a region of tissue;

passing the intensity data measurement through a first filter to produce a first output;

passing the intensity data measurement through a second filter to produce a second output;

analyzing fringe frequency data the first output and the second output to determine an indication of fluid flow in the region of tissue; and

in response to determining a positive indication of fluid flow in the region of tissue, analyzing the intensity data measurement to determine a blood analyte measurement.

13. The method of claim 12 further comprising:

analyzing a plurality of intensity data measurements for a same region of tissue to determine a blood analyte measurement.

14. The method of claim 13, wherein the plurality of intensity data measurements are obtained at a plurality of depths in the same region of tissue.

15. The method of claim 13, wherein the plurality of intensity data measurements are obtained at a plurality of times for the same region of tissue.

16. The method of claim 12, wherein the blood analyte measurement comprises a measurement of at least one of:

blood glucose, blood hemoglobin, or blood oxygen.

17. The method of claim 12, wherein determining the indication of fluid flow in the region of tissue comprises:

analyzing fringe frequency data in the first output and the second output.

18. The method of claim 17, wherein analyzing fringe frequency data comprises:

analyzing frequency modulation in the fringe frequency data in the first output and the second output.

19. The method of claim 17, wherein analyzing fringe frequency data comprises:

analyzing amplitude modulation in the fringe frequency data in the first output and the second output.

20. The method of claim 19, wherein analyzing fringe frequency data further comprises:

comparing speckle intensity in the first output and the second output.

21. The method of claim 20, wherein determining the indication of fluid flow in the region of tissue comprises:

comparing speckle intensity in the first output and the second output.