Systems and methods for measuring tissue oxygenation

Patent metadata

Field	Value
Publication number	US-9480424-B2
Application number	US-201514664793-A
Country	US
Kind code	B2
Filing date	Mar 20, 2015
Priority date	Mar 21, 2014
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

The disclosure provides methods and systems for determining tissue oxygenation. An electronic device obtains a data set including a plurality of images of a tissue of interest, each resolved at a different spectral band. Spectral analysis is performed, upon image registration, at a plurality of points in a two-dimensional area of the images of the tissue. The spectral analysis including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point in the plurality of points. The predetermined set of eight to twelve spectral bands includes spectral bands that provide improved methods for measuring tissue oxygenation.

First claim

What is claimed is:

1. A method for determining tissue oxygenation comprising:
at a system comprising a processor and memory, the memory including instructions for:
obtaining a data set comprising a plurality of images of a tissue of interest, each respective image in the plurality of images resolved at a different spectral band, in a predetermined set of eight to twelve spectral bands, and comprising an array of pixel values;
registering, using the processor, the plurality of images on a pixel-by-pixel basis, to form a plurality of registered images of the tissue; and
performing spectral analysis at a plurality of points in a two-dimensional area of the plurality of registered images of the tissue, the spectral analysis including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point in the plurality of points,
wherein the predetermined set of eight to twelve spectral bands includes spectral bands having central wavelengths of:
(i) 510±3 nm, 530±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 620±3 nm, and 660±3 nm,
(ii) 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 640±3 nm, or
(iii) 500±3 nm, 530±3 nm, 545±3 nm, 570±3 nm, 585±3 nm, 600±3 nm, 615±3 nm, and 640±3 nm; and

wherein each respective spectral band in the eight to twelve spectral bands has a full width at half maximum of less than 15 nm.

2. The method of claim 1 , wherein obtaining the data set comprises:
at the system:
capturing the plurality of images of the tissue of interest.

3. The method of claim 2 , wherein all of the plurality of images are captured concurrently.

4. The method of claim 2 , wherein a first subset of the plurality of images is captured concurrently at a first time point and a second subset of the plurality of images is captured concurrently at a second time point, other than the first time point.

5. The method of claim 2 , wherein the system is an imaging system and the spectral analysis is performed at the imaging system.

6. The method of claim 1 , wherein performing the spectral analysis comprises:
resolving absorption signals at each respective point in the plurality of points;
accounting for a melanin contribution and loss of signal from diffuse scattering at each respective point in the plurality of points, thereby forming a plurality of corrected absorption signals; and
determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels from the corrected absorption signals at each respective point in the plurality of points.

7. The method of claim 6 , wherein the contribution provided by melanin and the losses provided by diffuse scattering to the plurality of tissue oxygenation measurements are collectively modeled as a second order polynomial.

8. The method of claim 1 , wherein the predetermined set of eight to twelve spectral bands consists of a set of eight spectral bands, wherein the set of eight spectral bands have central wavelengths of:
(i) 510±3 nm, 530±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 620±3 nm, and 660±3 nm;
(ii) 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 640±3 nm; or
(iii) 500±3 nm, 530±3 nm, 545±3 nm, 570±3 nm, 585±3 nm, 600±3 nm, 615±3 nm, and 640±3 nm.

9. The method of claim 1 , wherein the predetermined set of eight to twelve spectral bands consists of a set of eight spectral bands, wherein the set of eight spectral bands have having central wavelengths of:
(i) 510±2 nm, 530±2 nm, 540±2 nm, 560±2 nm, 580±2 nm, 590±2 nm, 620±2 nm, and 660±2 nm;
(ii) 520±2 nm, 540±2 nm, 560±2 nm, 580±2 nm, 590±2 nm, 610±2 nm, 620±2 nm, and 640±2 nm; or
(iii) 500±2 nm, 530±2 nm, 545±2 nm, 570±2 nm, 585±2 nm, 600±2 nm, 615±2 nm, and 640±2 nm.

10. The method of claim 1 , wherein the predetermined set of eight to twelve spectral bands consists of a set of eight spectral bands, wherein the set of eight spectral bands have central wavelengths of:
(i) 510±1 nm, 530±1 nm, 540±1 nm, 560±1 nm, 580±1 nm, 590±1 nm, 620±1 nm, and 660±1 nm;
(ii) 520±1 nm, 540±1 nm, 560±1 nm, 580±1 nm, 590±1 nm, 610±1 nm, 620±1 nm, and 640±1 nm; or
(iii) 500±1 nm, 530±1 nm, 545±1 nm, 570±1 nm, 585±1 nm, 600±1 nm, 615±1 nm, and 640±1 nm.

11. The method of claim 1 , wherein the predetermined set of eight to twelve spectral bands consists of a set of eight spectral bands, where the set of eight spectral bands have central wavelengths of:
(i) 510 nm, 530 nm, 540 nm, 560 nm, 580 nm, 590 nm, 620 nm, and 660 nm;
(ii) 520 nm, 540 nm, 560 nm, 580 nm, 590 nm, 610 nm, 620 nm, and 640 nm; or
(iii) 500 nm, 530 nm, 545 nm, 570 nm, 585 nm, 600 nm, 615 nm, and 640 nm.

12. The method of claim 1 , wherein each respective spectral band in the eight to ten spectral bands has a full width at half maximum of less than 5 nm.

13. An electronic device, comprising:
one or more processors;
memory;
one or more programs, the one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for:
obtaining a data set comprising a plurality of images of a tissue of interest, each respective image in the plurality of images resolved at a different spectral band in a predetermined set of eight to twelve spectral bands, and comprising an array of pixel values;
registering, using the processor, the plurality of images on a pixel-by-pixel basis, to form a plurality of registered images of the tissue; and
performing spectral analysis at a plurality of points in a two-dimensional area of the plurality of registered images of the tissue, the spectral analysis including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point in the plurality of points,
wherein the predetermined set of eight to twelve spectral bands includes spectral bands having central wavelengths of:
(i) 510±3 nm, 530±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 620±3 nm, and 660±3 nm;
(ii) 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 640±3 nm; or
(iii) 500±3 nm, 530±3 nm, 545±3 nm, 570±3 nm, 585±3 nm, 600±3 nm, 615±3 nm, and 640±3 nm; and

wherein each respective spectral band in the eight to twelve spectral bands has a full width at half maximum of less than 15 nm.

14. The electronic device of claim 13 , wherein the electronic device is an imaging system further comprising:
one or more photo-sensors, the one or more photo-sensors in electronic communication with the one or more processors and configured to resolve light of the predetermined set of eight to twelve spectral bands, and
wherein the instructions for obtaining the data set include instructions for capturing the plurality of images of the tissue of interest using the one or more photo-sensors.

15. The electronic device of claim 14 , wherein the plurality of images is captured concurrently.

16. The electronic device of claim 14 , wherein a first subset of the plurality of images is captured concurrently at a first time point and a second subset of the plurality of images is captured concurrently at a second time point, other than the first time point.

17. The electronic device of claim 13 , wherein the instructions for performing the spectral analysis includes instructions for:
resolving absorption signals at each respective point in the plurality of points;
accounting for a melanin contribution and loss of signal from diffuse scattering at each respective point in the plurality of points, thereby forming a plurality of corrected absorption signals; and
determining approxima

Assignees

• Hypermed Imaging Inc

Inventors

• Darty Mark Anthony
• Yudovsky Dmitry

Classifications

• A61B5/0077

  Devices for viewing the surface of the body, e.g. camera, magnifying lens · CPC title

• A61B2562/0233

  Special features of optical sensors or probes classified in A61B5/00 · CPC title

• G06T2207/10024

  Color image · CPC title

• A61B2576/00

  Medical imaging apparatus involving image processing or analysis (A61B1/00009, A61B6/52 and A61B8/52 take precedence) · CPC title

• G06T7/0012

  Biomedical image inspection · CPC title