Method and apparatus for OCT-based viscometry

Patent metadata

Field	Value
Publication number	US-10258238-B2
Application number	US-201815880734-A
Country	US
Kind code	B2
Filing date	Jan 26, 2018
Priority date	Feb 17, 2017
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

Methods and apparatus for ascertaining a relative viscosity characterizing a fluid sample. The fluid sample is illuminated through a scattering membrane adjacent to the fluid with broadband radiation. Scattering from particles within the fluid sample characterized by a distribution of characteristic dimensions spanning at least two orders of magnitude is detected, generating a detector signal as a function of depth relative to a specified surface of the scattering membrane at a plurality of temporal delays. A cross-correlation function of at least one of amplitude, phase and intensity of a scattered optical field is derived for a plurality of depths relative to the specified surface. A mean cross-correlation function is then derived for each depth and fit to obtain a diffusion coefficient, from which a relative viscosity characterizing the fluid is derived.

First claim

We claim:

1. A method for ascertaining a relative viscosity characterizing a fluid sample, the method comprising:
a. illuminating the fluid sample through a scattering membrane adjacent to the fluid with broadband radiation having a fraction bandwidth, at half-maximum, of at least 10%;
b. detecting scattering from scattering particles within the fluid sample, the scattering particles characterized by a distribution of characteristic dimensions spanning at least two orders of magnitude;
c. generating a wavelength-resolved detector signal for deriving coherent scatter as a function of depth relative to a specified surface of the scattering membrane at a plurality of temporal delays;
d. interferometrically deriving at least one of amplitude, phase and intensity of a scattered optical field for a plurality of depths relative to the specified surface;
e. calculating a mean cross-correlation function for each depth;
f. fitting the mean cross-correlation function for the plurality of depths to obtain a diffusion coefficient; and
g. deriving the relative viscosity characterizing the fluid based on the diffusion coefficient.

2. A method in accordance with claim 1 , wherein illuminating the fluid sample through a scattering membrane adjacent to the fluid sample includes transmitting the broadband radiation through an intervening biological membrane.

3. A method in accordance with claim 2 , wherein the intervening biological tissue is a tympanic membrane.

4. A method in accordance with claim 1 , wherein the fluid sample is a middle ear effusion.

5. A method in accordance with claim 1 , further comprising calibrating a cross-correlation function decay rate relative to viscosity on the basis of a reference fluid of known viscosity.

6. A method in accordance with claim 4 , further comprising grading the middle ear effusion with respect to at least one of serosity and mucosity.

Assignees

• Univ Illinois

Inventors

• Boppart Stephen A
• Monroy Guillermo Luciano
• Pande Paritosh

Classifications

• G01N21/4795

  spatially resolved investigating of object in scattering medium (in vivo A61B) · CPC title

• A61B5/7257

  using Fourier transforms · CPC title

• G01B9/02044

  Imaging in the frequency domain, e.g. by using a spectrometer · CPC title

• A61B6/508

  for non-human patients · CPC title

• A61B5/0075

  by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy (A61B5/0071 takes precedence) · CPC title