Non-invasive optical detection system and method of multiple-scattered light with swept source illumination

Patent metadata

Field	Value
Publication number	US-11547303-B2
Application number	US-201916393002-A
Country	US
Kind code	B2
Filing date	Apr 24, 2019
Priority date	May 4, 2018
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

An optical source sweeps a source light over an optical wavelength range. An interferometer splits the source light into sample light and reference light, delivers the sample light into an anatomical structure, such that the sample light is scattered by the anatomical structure, resulting in physiological-encoded signal light that exits the anatomical structure, and combines the signal light and the reference light into an interference light pattern having an array of spatial components and a plurality of oscillation frequency components. An optical detector array detects intensity values of the array of spatial components. A processor derives an array of intensity values of each oscillation frequency component from the detected spatial component intensity value array, reduces each derived oscillation frequency component intensity value array to a single frequency component intensity value, and determines a depth of a physiological event in the anatomical structure based on the reduced frequency component intensity values.

First claim

What is claimed is:

1. A non-invasive optical measurement system, comprising:
an optical source configured for sweeping a source light over a range of optical wavelengths during each of at least one measurement period;
an interferometer configured for splitting the source light into sample light and reference light, delivering the sample light into an anatomical structure, such that the sample light is scattered by the anatomical structure, resulting in physiological-encoded signal light that exits the anatomical structure, and combining, during each of the at least one measurement period, the physiological-encoded signal light and the reference light into an interference light pattern having an array of spatial components and a plurality of oscillation frequency components, the plurality of oscillation frequency components respectively encoded with a plurality of different depths of the anatomical structure;
an optical detector array configured for detecting intensity values of the array of spatial components of the interference light pattern during each of the at least one measurement period, the optical detector array comprising an M×N array of optical detectors, wherein each of M and N is greater than one; and
a processor configured for sequentially deriving an array of intensity values of each oscillation frequency component of the interference light pattern over the optical detector array from the detected spatial component intensity value array of the interference light pattern during the at least one measurement period, reducing each derived oscillation frequency component intensity value array to a single frequency component intensity value by computing a mean of the respective derived oscillation frequency component intensity value array over at least two optical detectors of the optical detector array oriented in an M-direction and at least two optical detectors of the optical detector array oriented in an N-direction, and determining a depth of a physiological event in the anatomical structure, at least partially, based on the reduced frequency component intensity values.

2. The non-invasive optical measurement system of claim 1 , wherein the anatomical structure is a brain.

3. The non-invasive optical measurement system of claim 2 , wherein the physiological event is indicative of neural activity.

4. The non-invasive optical measurement system of claim 3 , wherein the physiological event is a fast-optical signal.

5. The non-invasive optical measurement system of claim 1 , wherein each of the at least one measurement period is equal to or less than a speckle decorrelation time of the anatomical structure.

6. The non-invasive optical measurement system of claim 1 , wherein each of the at least one measurement period is equal to or less than 100 microseconds.

7. The non-invasive optical measurement system of claim 1 , wherein each of the at least one measurement period is equal to or less than 10 microseconds.

8. The non-invasive optical measurement system of claim 1 , wherein the processor is configured for determining the depth of the physiological event in the anatomical structure, at least partially, by comparing the reduced oscillation frequency component intensity values to corresponding reference oscillation frequency component intensity values.

9. The non-invasive optical measurement system of claim 1 , wherein the at least one measurement period comprises a single measurement period, and wherein the processor is configured for sequentially deriving each oscillation frequency component intensity array over the optical detector array from the detected spatial component intensity value array of the interference light pattern during the single measurement period by computing a Fourier transform of the detected spatial component intensity value array of the interference light pattern.

10. The non-invasive optical measurement system of claim 9 , further comprising a charged coupled device (CCD) camera comprising the optical detector array.

11. The non-invasive optical measurement system of claim 1 , wherein the at least one measurement period comprises a plurality of measurement periods, and wherein the processor is configured for sequentially deriving each oscillation frequency component intensity value array over the optical detector array from the detected spatial component intensity value array of the interference light pattern during each respective one of the measurement periods.

12. The non-invasive optical measurement system of claim 11 , wherein the processor is configured for sequentially deriving each oscillation frequency component intensity value array over the optical detector array from the detected spatial component intensity value array of the interference light pattern during each respective one of the measurement periods by locking in each oscillation frequency component during each respective one of the measurement periods.

13. The non-invasive optical measurement system of claim 12 , wherein the processor is configured for locking in each oscillation frequency component during each respective one of the measurement periods by accumulating at least two sequential ones of the intensity values detected during each cycle of the respective oscillation frequency component respectively in at least two bins, and performing a function on the accumulated contents of the at least two bins.

14. The non-invasive optical measurement system of claim 13 , wherein the at least two bins comprises only two bins, and the function is computing the difference between the accumulated contents of the two bins.

15. The non-invasive optical measurement system of claim 13 , wherein the at least two bins comprises only four bins, and the function is computing a quadrature of the accumulated contents of the four bins.

16. The non-invasive optical measurement system of claim 12 , further comprising a lock-in camera that includes the optical detector array and a portion of the processor that is configured for locking in each oscillation frequency component during each respective one of the measurement periods.

17. The non-invasive optical measurement system of claim 16 , further comprising a central processing unit (CPU) that includes another portion of the processor that is configured for reducing the derived array of intensity values of each oscillation frequency component to the single frequency component value, and determining the depth of the physiological event in the anatomical structure, at least partially, based on the reduced frequency component values.

18. The non-invasive optical measurement system of claim 1 , wherein the interference light pattern is a speckle light pattern, and the spatial components are speckle grains.

19. The non-invasive optical measurement system of claim 1 , wherein the optical source light has a spectral linewidth of less than 2 pm.

20. The non-invasive optical measurement system of claim 1 , wherein the optical source light has a spectral linewidth of less than 0.5 pm.

21. The non-invasive optical measurement system of claim 1 , wherein the optical wavelength range is greater than 3 pm.

22. The non-invasive optical measurement system of claim 1 , wherein the optical wavelength range is greater than 30 pm.

23. The non-invasive optical measurement system of claim 1 , wherein the mean of the respective derived oscillation frequency component intensity value array is computed over all optical detectors of the optical detector array.

Assignees

• Hi Llc

Inventors

• Ruan Haowen
• Marblestone Adam
• Horstmeyer Roarke
• Shen Yuecheng
• Zhou Haojiang
• Alford Jamu

Classifications

• A61B5/0082 Primary

  adapted for particular medical purposes · CPC title

• A61B5/4064

  Evaluating the brain (for intracranial pressure A61B5/031; for cerebral blood gases A61B5/14553; using EEG A61B5/369) · CPC title

• A61B2562/04

  Arrangements of multiple sensors of the same type · CPC title

• A61B5/6814

  Head · CPC title

• A61B5/0066 Primary

  Optical coherence imaging · CPC title