OCT based method for diagnosis and therapy

• US 7,510,849 B2
• Filed: 01/21/2005
• Issued: 03/31/2009
• Est. Priority Date: 01/29/2004
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: GlucoLight Corporation
• Inventors: Schurman, Matthew J., Shakespeare, Walter Jeffrey
• Primary Examiner(s): Tsang; Cecilia
• Assistant Examiner(s): Wood; Amanda P
• Application Number:
  US11/040,388
• Publication Number:
  US 20050186648A1
• Time in Patent Office: 1,530 Days
• Field of Search: None
• US Class Current: 435/14
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement

Abstract

This invention relates to a method of diagnosing or treating a biological subject, such as a person or animal, comprising the steps of subjecting at least a microsample of the subject'"'"'s tissue to a physiological perturbation and measuring the response of the microsample to the perturbation using optical coherence tomography (OCT). In an exemplary embodiment, the concentration of glucose in the microsample is perturbed, as by providing the subject with a high glucose drink, and subsequently monitoring at a high sample rate in a microsample by OCT. Pathology, such as diabetes, can be diagnosed by deviation of the concentration vs. time response over several cells (micro-oscillation) from the micro-oscillation in the cells of a healthy subject. Other applications include diagnosing or treating de-hydration and diseases that cause changes in the osmolyte concentrations and thus the osmotic pressure in the cells in tissue.

Claims

1. A method of characterizing a patient'"'"'s blood glucose concentrations based on optical coherence tomography, the method comprising:

employing optical coherence tomography to measure light reflected from a patient'"'"'s skin tissue at a plurality of depths;

determining a tissue scattering coefficient for a tissue region based on differences in light reflected at different depths;

detecting micro-oscillations in the tissue scattering coefficient over a time interval; and

relating the micro-oscillations to the patient'"'"'s blood glucose concentrations.

2. The method of claim 1, wherein the step of employing optical coherence tomography to measure reflected light further comprises obtaining a plurality of reflected light intensity measurements at varying tissue depths, each measurement obtained by interfering a tissue-reflected light beam with a reference-reflected light beam, the path length of the reference-reflected light beam determining a tissue depth for each measurement.

3. The method of claim 1, wherein the step of determining a tissue scattering coefficient for a tissue region further comprises selecting a function that describes a relationship between reflected light measurements and their corresponding depths and applying the function to determine the scattering coefficient.

4. The method of claim 3, wherein the function is a slope function.

5. The method of claim 1, wherein the method further comprises detecting micro-oscillations having a period less than about 20 minutes.

6. The method of claim 1, wherein the step of relating the micro-oscillations further comprises relating a period of the micro-oscillations to a patient'"'"'s insulin response to blood glucose concentrations.

7. The method of claim 1, wherein the step of relating the micro-oscillations further comprises relating an amplitude of the micro-oscillations to a patient'"'"'s insulin response to blood glucose concentrations.

8. The method of claim 1, wherein the patient has diabetes.

9. The method of claim 1, wherein the step of relating the micro-oscillations further comprises relating the micro-oscillations with an insulin response in the patient.

10. The method of claim 1, wherein the method further comprises providing a glucose sample to the patient.

11. The method of claim 10, wherein the method further comprises relating a condition of the tissue with an impulse response due to the glucose sample.

12. The method of claim 1, further comprising:

modulating insulin dosing in the patient such that micro-oscillations of the tissue scatter coefficient in the patient approach a normal micro-oscillation response to glucose dosing in a healthy patient.

13. The method of claim 1, wherein the step of relating the micro-oscillations further comprises characterizing health of an organ or system of the patient based upon the detected micro-oscillations in the tissue scattering coefficient over the time interval.