Non-invasive optical detection systems and methods in highly scattering medium

Patent metadata

Field	Value
Publication number	US-11206985-B2
Application number	US-201916299067-A
Country	US
Kind code	B2
Filing date	Mar 11, 2019
Priority date	Apr 13, 2018
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A non-invasive optical detection system and method are provided. Sample light is delivered into a target volume of interest, whereby the sample light is scattered by the target volume of interest, resulting in a sample light pattern that exits the anatomical structure. Reference light is combined with the sample light pattern to generate at least one interference light pattern, each of which may have a time varying interference component that integrates to a first value in the absence of the physiological event, and that integrates to a second greater value in the presence of the physiological event. Intensities of spatial components of each interference light pattern are detected during a measurement period. A function of the detected spatial component intensities of the interference light pattern(s) is analyzed, and a presence of the physiological event in the target volume of interest is determined based on the analysis.

First claim

What is claimed is:

1. A non-invasive optical detection system, comprising:
an interferometer configured for delivering sample light having a rectangular pulse into a target volume of interest of an anatomical structure, whereby the sample light is scattered by the target volume of interest, resulting in a sample light pattern that exits the anatomical structure, the interferometer further configured for combining reference light with the sample light pattern to generate at least one interference light pattern, such that each of the at least one interference light pattern has a time varying interference component that integrates to a first value over a measurement period in the absence of a physiological event in the target volume of interest, and that integrates to a second value greater than the first value over the measured period in the presence of the physiological event, wherein the interferometer is further configured for shifting the sample light relative to the reference light by a frequency offset, such that the sample light pattern and the reference light are combined using a heterodyning technique, the measurement period is equal to an inverse of the frequency offset between the sample light and the reference light, and the product of the frequency offset between the sample light and the reference light and a duration of the rectangular pulse is equal to one;
at least one array of detectors respectively configured for detecting intensities of spatial components of the at least one interference light pattern during the measurement period; and
a processor configured for analyzing a function of the detected spatial component intensities of the at least one interference light pattern, and identifying a presence of the physiological event in the target volume of interest based on the analysis.

2. The non-invasive optical detection system of claim 1 , wherein the first value is approximately a zero value.

3. The non-invasive optical detection system of claim 2 , wherein the first value is equal to or less than one percent of the integral of the absolute function of the time varying interference component.

4. The non-invasive optical detection system of claim 1 , wherein the target volume of interest comprises brain tissue and the physiological event is a fast-optical signal, wherein the system is configured for determining neural activity within the brain tissue based on the fast-optical signal.

5. The non-invasive optical detection system of claim 1 , further comprising a controller configured for using feedback control to periodically modify one or more of a waveform shape of the sample light and the frequency offset between the sample light and the reference light to minimize the first value.

6. The non-invasive optical detection system of claim 1 , wherein the interferometer comprises a light source configured for generating source light, a beam splitter configured for splitting the source light into the sample light and the reference light.

7. The non-invasive optical detection system of claim 1 , wherein the processor is configured for analyzing the function of the detected spatial component intensities of the at least one interference light pattern by analyzing an intensity population distribution of the function of the detected spatial component intensities of the at least one interference light pattern, and determining a spread of the analyzed intensity population distribution, and wherein the presence of the physiological event in the target volume of interest is identified based on the determined intensity population distribution spread.

8. The non-invasive optical detection system of claim 7 , wherein the processor is configured for determining the intensity population distribution spread by computing a standard deviation of the intensity population distribution.

9. The non-invasive optical detection system of claim 7 , wherein the processor is configured for quantifying the spread of the intensity population distribution, and identifying the presence of the physiological event in the tissue voxel only if the quantified intensity population distribution spread is greater than a reference threshold.

10. The non-invasive optical detection system of claim 9 , wherein the processor is configured for determining a magnitude of the physiological event based on the quantified intensity population distribution spread.

11. A non-invasive optical detection method, comprising:
delivering sample light having a rectangular pulse into a target volume of interest of an anatomical structure, whereby the sample light is scattered by the target volume of interest, resulting in a sample light pattern that exits the anatomical structure;
shifting the sample light relative to reference light by a frequency offset;
combining reference light with the sample light pattern using a heterodyning technique to generate at least one interference light pattern, such that each of the at least one interference light pattern has a time varying interference component that integrates to a first value over a measurement period in the absence of a physiological event in the target volume of interest, and that integrates to a second value greater than the first value over the measured period in the presence of the physiological event, wherein the measurement period is equal to an inverse of the frequency offset between the sample light and the reference light, and the product of the frequency offset between the sample light and the reference light and a duration of the rectangular pulse is equal to one;
detecting intensities of spatial components of each of the at least one interference light pattern during the measurement period;
analyzing a function of the detected spatial component intensities of the at least one interference light pattern; and
identifying a presence of the physiological event in the target volume of interest based on the analysis.

12. The non-invasive optical detection method of claim 11 , wherein the first value is approximately a zero value.

13. The non-invasive optical detection method of claim 11 , wherein the first value is equal to or less than one percent of the integral of the absolute function of the time varying interference component.

14. The non-invasive optical detection method of claim 11 , wherein the target volume of interest comprises brain tissue and the physiological event is a fast-optical signal, and wherein the method further comprises determining neural activity within the brain tissue based on the fast-optical signal.

15. The non-invasive optical detection method of claim 11 , further comprising using feedback control to periodically modify one or more of a waveform shape of the sample light and the frequency offset between the sample light and the reference light to minimize the first value.

16. The non-invasive optical detection method of claim 11 , wherein analyzing the function of the detected spatial component intensities of the at least one interference light pattern comprises analyzing an intensity population distribution of the function of the detected spatial component intensities of the at least one interference light pattern, and determining a spread of the analyzed intensity population distribution, and wherein the presence of a physiological event in the tissue voxel is identified based on the determined intensity population distribution spread.

17. The non-invasive optical detection method of claim 16 , wherein the determining the intensity population distribution spread comprises computing a standard deviation of the intensity population distributi

Assignees

• Hi Llc

Inventors

• Alford Jamu
• Marblestone Adam

Classifications

• A61B5/0042 Primary

  for the brain · CPC title

• A61B5/0013

  Medical image data (A61B1/00011, A61B6/56, A61B8/56 take precedence) · CPC title

• A61B5/6803

  Head-worn items, e.g. helmets, masks, headphones or goggles · CPC title

• A61B2562/0238

  Optical sensor arrangements for performing transmission measurements on body tissue · CPC title

• A61B5/0059 Primary

  using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455) · CPC title