IP Library › Granted Patent US 12,569,154
Granted Patent B2
US 12,569,154 · App. 18/029,649 · Granted Mar 10, 2026

Pathlength resolved CW-light source based diffuse correlation spectroscopy

Inventors: Abdul Mohaimen Safi (Tampa, FL); Ashwin Bharadwaj Parthasarathy (Tampa, FL); Sadhu Moka (Tampa, FL)
Assignee: University of South Florida
A61B5/0261A61B5/0075
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 12,569,154
App. No.
18/029,649
Granted
Mar 10, 2026
Kind
B2
Abstract

A system configured to perform the DCS-type measurements with the use of low-coherence continuous-wave (CW) light source at levels of light intensities that are substantially lower and with pathlengths through the tissue that are substantially longer than those afforded by the use of conventional methods. The method includes utilizing the optical detection system to producing signals representing interference between the portion of CW light arriving through reference arm of interferometer and the sample CW light potion that has traversed the sample arm including different paths through the target tissue while switching between first and second of said different paths only by adjusting a delay in the delay line. The spatial resolution of different pathlengths of sample light through tissue is defined by coherence length of CW light.

Claims (47)

1 . A method for performing a pathlength-resolved diffuse correlation spectroscopy (PR-DCS) measurement of a target tissue, the method comprising:

directing a first portion of a spatially multi-mode light that has an electric field and a coherence length and that is generated by a continuous-wave light source to a first surface area of the target tissue while directing a second portion of the spatially multi-mode light generated by the continuous-wave light source to an optical detection system through a delay line through a single optical channel;

receiving light of the first portion of the spatially multi-mode light, which has traversed the target tissue, at a second surface area of the target tissue as a sample light and directing the sample light through the single optical channel to the optical detection system,

wherein the first and second surface areas of the target tissue are spatially separated from one another by a separation distance;

at a single photodetector of the optical detection system;

a) receiving both

the second portion of the spatially multi-mode light transmitted through the single optical channel and

the first portion of the spatially multi-mode light that has traversed different paths through the target tissue between the first and second surface areas and that has transmitted through the single optical channel, and

b) generating a single signal of intensity of interference of the second portion and the first portion of the light at the single photodetector, wherein the intensity of the interference includes both a coherent contribution of the first and second portions of the spatially multi-mode light and an incoherent contribution of the first and second portions received at the single photodetector

while switching between first and second of the different paths only by adjusting a delay in the delay line,

and

with the use of electronic circuitry, configured to receive the single signal of the intesity of the interference from the single photodetector:

identifying a pathlength-resolved autocorrelation function of the electric field based on a pathlength-resolved intensity autocorrelation function of the single signal of the intensity of the interference and a variable that is dependent on a path of the first portion of the spatially multi-mode light through the target tissue;

determining a blood flow in the target tissue at least in part by numerically fitting the pathlength-resolved autocorrelation function of the electric field to a negative exponential that is dependent on the blood flow.

2 . A method according to claim 1 , wherein the directing the first portion of the spatially multi-mode light to the first surface area includes at least one of:

(a) directing the first portion of the spatially multi-mode light having a coherence length of at least 0.05 mm;

(b) directing the first portion of the spatially multi-mode light generated by the continuous-wave light source that is configured to generate spatially multi-mode distribution of the light; and

(c) the coherence length being a pathlength resolution of the PR-DCS measurement.

3 . A method according to claim 2 , wherein the switching between first and second of the different paths only by the adjusting time delay in the delay line includes switching between the first and second of the different paths with the pathlength resolution defined by the coherence length.

4 . A method according to claim 1 , wherein at least one of the directing the first portion of the light through the single optical channel and the directing the second portion of the light through the single optical channel includes transmitting light through free space or through an optical fiber.

5 . A method according to claim 1 , wherein the switching between the first and second of the different paths includes changing a pathlength of the sample light through the target tissue with an increment substantially equal to the coherence length.

6 . A method according to claim 1 , wherein the continuous-wave light source is configured to generate the spatially multi-mode light having such a degree of coherence that a signal from the signals representing the interference and produced at the optical detection system represents interference between the second portion of the light and the sample light that has traversed a volume of the target tissue at a depth of at least 1 cm below a surface of the target tissue.

7 . A method according to claim 1 , wherein the continuous-wave light source is configured to generate the spatially multi-mode light having such a degree of coherence that the sample light and the second portion of the light interfere with one another at the optical detection system while at least one of the following conditions is satisfied:

(a) the sample light is produced at the second surface portion that is separated from the first surface portion by the separation distance exceeding 2.5 cm; and

(b) the sample light represents the light from the first portion of the spatially multi-mode light that has traversed a pathlength greater than the separation distance.

8 . A method according to claim 1 , further comprising: determining intensity autocorrelation functions and parameters characterizing the target tissue traversed by each of the different paths through the target by using electronic circuitry configured to receive the signals from the optical detection system.

9 . A method according to claim 8 , further comprising:

numerically determining perfusion in the target tissue based at least on numerically fitting the intensity autocorrelation functions characterizing the target tissue to a negative exponential function, wherein an argument of the negative exponential function includes a product of the perfusion and a squared value of a wave vector representing the sample light but is independent from an absorption coefficient of the target tissue; and

determining both a scattering coefficient of the target tissue and the absorption coefficient of the target tissue.

10 . A method according to claim 8 , further comprising determining values of intensities of the sample light for each of the different paths.

11 . A method according to claim 8 , wherein the determining includes numerically fitting the intensity autocorrelation functions characterizing the target tissue to a negative exponential function that depends from a wave vector value representing the sample light but is independent from an absorption coefficient of the target tissue.

12 . A method according to claim 11 , wherein said continuous-wave light source is configured to generate the spatially multi-mode light having such a degree of coherence that the sample light and the second portion of the light interfere with one another at the optical detection system while the sample light represents the light from the first portion of the light that has traversed a pathlength greater than the separation distance.

13 . A method according to claim 12 , further comprising:

recording a parameter of the blood flow at a first rate of lower than 20 Hz or at a second rate between 20 Hz and 100 Hz through the target tissue as a function of a depth of a given path, from the different paths, in the target tissue.

14 . A method according to claim 1 , further comprising:

recording a parameter of the blood flow through the target tissue as a function of a depth of a given path, from the different paths, in the target tissue.

15 . A method according to claim 14 , wherein the recording the parameter of the blood flow includes recording the parameter of the blood flow at a rate of:

(a) lower than 20 Hz; or

(b) between 20 Hz and 100 Hz; or

(c) greater than 100 Hz.

16 . A method according to claim 1 , the method being devoid of using a source of pulsed light or a light source configured to generate modulated light.

17 . A method according to claim 1 , wherein the directing the first portion of the spatially multi-mode light to the first surface area includes directing the first portion of the spatially multi-mode light generated by the continuous-wave light source.

18 . A method according to claim 17 , wherein the continuous-wave light source is configured to generate the spatially multi-mode light having such a degree of coherence that the sample light and the second portion of the light interfere with one another at the optical detection system while the sample light represents the light from the first portion of the spatially multi-mode light that has traversed a pathlength greater than the separation distance.

19 . A method according to claim 17 , further comprising:

recording a parameter of the blood flow at a first rate of lower than 20 Hz or at a second rate between 20 Hz and 100 Hz through the target tissue as a function of a depth of a given path, from the different paths, in the target tissue.

20 . A method according to claim 1 , further comprising:

recording a parameter of the blood flow at a first rate of lower than 20 Hz or at a second rate between 20 Hz and 100 Hz through the target tissue as a function of a depth of a given path, from the different paths, in the target tissue.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 17, 2023
From: SAFI, ABDUL MOHAIMEN; PARTHASARATHY, ASHWIN BHARADWAJ; MOKA, SADHU
To: UNIVERSITY OF SOUTH FLORIDA
Reel/Frame 064617/0328 →
Continuity (3)
Provisional Application 63155505 · Mar 2, 2021
Provisional Application 63198181 · Oct 1, 2020
Related Publication 20230363657A1 · Nov 16, 2023
References Cited (66)
US 6076010A · Boas · 2000 [cited by examiner]
US 7061622B2 · Rollins et al. · 2006 [cited by applicant]
US 10962414B2 · Durduran · 2021 [cited by applicant]
US 20060063995A1 · Yodh · 2006 [cited by examiner]
US 20110282331A1 · Brennan · 2011 [cited by examiner]
US 20190053721A1 · Boas et al. · 2019 [cited by applicant]
US 20190120608A1 · Kennedy · 2019 [cited by examiner]
US 20190336001A1 · Zhou · 2019 [cited by examiner]
US 20190336007A1 · Ruan et al. · 2019 [cited by applicant]
US 20190336060A1 · Shen et al. · 2019 [cited by applicant]
US 20200060542A1 · Alford et al. · 2020 [cited by applicant]
US 20200225021A1 · Wei · 2020 [cited by examiner]
US 20220361764A1 · Sutin · 2022 [cited by examiner]
EP 0628804A1 · 1994 [cited by applicant]
WO 2019204231A1 · 2019 [cited by applicant]
WO 2022072353A1 · 2022 [cited by applicant]
Yodh, A. G., Kaplan, P. D., & Pine, D. J. (1990). Pulsed diffusing-wave spectroscopy: High resolution through nonlinear optical gating. In XVII International Conference on Quantum Electronics. Digest of Publ by IEEE. (Y… [cited by examiner]
Pagliazzi M, Sekar SKV, Colombo L, Martinenghi E, Minnema J, Erdmann R, Contini D, Mora AD, Torricelli A, Pifferi A, Durduran T. Time domain diffuse correlation spectroscopy with a high coherence pulsed source: in vivo … [cited by examiner]
International Search Report of Related PCT/US2021/052419, mailed Jan. 27, 2022, 3 pages. [cited by applicant]
Written Opinion of Related PCT/US2021/052419, mailed Jan. 27, 2022, 9 pages. [cited by applicant]
Safi, Abdul Mohaimen, et al. “Quantitative measurement of static and dynamic tissue optical properties with continuous wave pathlength resolved diffuse correlation spectroscopy.” Optics and the Brain. Optica Publishing … [cited by applicant]
Graduate Research Symposium, “Tittle: Continuous Wave Path-resolved Diffuse Correlation Spectroscopy System for Quantifying Deep Tissue Physiology” Apr. 9, 2021. [cited by applicant]
Pagliazzi, M., et al. “In vivo time domain speckle contrast optical spectroscopy.” European Conference on Biomedical Optics. Optica Publishing Group, 2019. [cited by applicant]
Borycki, Dawid, et al. “Interferometric Near-Infrared Spectroscopy (iNIRS) for determination of optical and dynamical properties of turbid media.” Optics express 24.1 (2016): 329-354. [cited by applicant]
Borycki, Dawid, et al. “Reflectance-mode interferometric near-infrared spectroscopy quantifies brain absorption, scattering, and blood flow index in vivo.” Optics letters 42.3 (2017): 591-594. [cited by applicant]
Pagliazzi, M., et al. “Time domain diffuse correlation spectroscopy with a high coherence pulsed source: in vivo and phantom results.” Biomedical optics express 8.11 (2017): 5311-5325. [cited by applicant]
Samaei, Saeed, et al. “Time-domain diffuse correlation spectroscopy (TD-DCS) for noninvasive, depth-dependent blood flow quantification in human tissue in vivo.” Scientific reports 11.1 (2021): 1817. [cited by applicant]
Sutin, Jason, et al. “Time-domain diffuse correlation spectroscopy.” Optica 3.9 (2016): 1006-1013. [cited by applicant]
Kholiqov, Oybek, et al. “Time-of-flight resolved light field fluctuations reveal deep human tissue physiology.” Nature communications 11.1 (2020): 391. [cited by applicant]
Devor, A. et al. Frontiers in optical imaging of cerebral blood flow and metabolism. Journal of Cerebral Blood Flow & Metabolism 32, 1259-1276, doi:10.1038/jcbfm.2011.195 (2012). [cited by applicant]
Devor, Anna, et al. “Frontiers in optical imaging of cerebral blood flow and metabolism.” Journal of Cerebral Blood Flow & Metabolism 32.7 (2012): 1259-1276. [cited by applicant]
Boas, David A., and Arjun G. Yodh. “Spatially varying dynamical properties of turbid media probed with diffusing temporal light correlation.” JOSA A 14.1 (1997): 192-215. [cited by applicant]
Durduran, Turgut, and Arjun G. Yodh. “Diffuse correlation spectroscopy for non-invasive, micro-vascular cerebral blood flow measurement.” Neuroimage 85 (2014): 51-63. [cited by applicant]
Yu, Guoqiang, et al. “Validation of diffuse correlation spectroscopy for muscle blood flow with concurrent arterial spin labeled perfusion MRI.” Optics express 15.3 (2007): 1064-1075. [cited by applicant]
Mesquita, Rickson C., et al. “Direct measurement of tissue blood flow and metabolism with diffuse optics.” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369. 1955 (20… [cited by applicant]
Buckley, Erin M., et al. “Cerebral hemodynamics in preterm infants during positional intervention measured with diffuse correlation spectroscopy and transcranial Doppler ultrasound.” Optics Express 17.15 (2009): 12571-1… [cited by applicant]
Buckley, Erin M., et al. “Validation of diffuse correlation spectroscopic measurement of cerebral blood flow using phase-encoded velocity mapping magnetic resonance imaging.” Journal of biomedical optics 17.3 (2012): 03… [cited by applicant]
Durduran, Turgut, et al. “Transcranial optical monitoring of cerebrovascular hemodynamics in acute stroke patients.” Optics express 17.5 (2009): 3884-3902. [cited by applicant]
Favilla, Christopher G., et al. “Optical bedside monitoring of cerebral blood flow in acute ischemic stroke patients during head-of-bed manipulation.” Stroke 45.5 (2014): 1269-1274. [cited by applicant]
Jain, Varsha, et al. “Cerebral oxygen metabolism in neonates with congenital heart disease quantified by MRI and optics.” Journal of Cerebral Blood Flow & Metabolism 34.3 (2014): 380-388. [cited by applicant]
Yu, Guoqiang, et al. “Time-dependent blood flow and oxygenation in human skeletal muscles measured with noninvasive near-infrared diffuse optical spectroscopies.” Journal of biomedical optics 10.2 (2005): 024027-024027. [cited by applicant]
Mesquita, Rickson C., et al. “Optical monitoring and detection of spinal cord ischemia.” PLoS One 8.12 (2013): e83370. [cited by applicant]
Wang, Detian, et al. “Fast blood flow monitoring in deep tissues with real-time software correlators.” Biomedical optics express 7.3 (2016): 776-797. [cited by applicant]
Biswas, Arindam, et al. “Fast diffuse correlation spectroscopy with a low-cost, fiber-less embedded diode laser.” Biomedical Optics Express 12.11 (2021): 6686-6700. [cited by applicant]
Tamborini, Davide, et al. “Development and characterization of a multidistance and multiwavelength diffuse correlation spectroscopy system.” Neurophotonics 5.1 (2018): 011015-011015. [cited by applicant]
Carp, Stefan A., et al. “Combined multi-distance frequency domain and diffuse correlation spectroscopy system with simultaneous data acquisition and real-time analysis.” Biomedical optics express 8.9 (2017): 3993-4006. [cited by applicant]
Mesquita, Rickson C., et al. “Influence of probe pressure on the diffuse correlation spectroscopy blood flow signal: extra-cerebral contributions.” Biomedical optics express 4.7 (2013): 978-994. [cited by applicant]
Baker, Wesley B., et al. “Pressure modulation algorithm to separate cerebral hemodynamic signals from extracerebral artifacts.” Neurophotonics 2.3 (2015): 035004-035004. [cited by applicant]
Cheung, Cecil, et al. “In vivo cerebrovascular measurement combining diffuse near-infrared absorption and correlation spectroscopies.” Physics in Medicine & Biology 46.8 (2001): 2053. [cited by applicant]
Farzam, Parisa, et al. “Shedding light on the neonatal brain: probing cerebral hemodynamics by diffuse optical spectroscopic methods.” Scientific reports 7.1 (2017): 15786. [cited by applicant]
Kim, Meeri N., et al. “Noninvasive measurement of cerebral blood flow and blood oxygenation using near-infrared and diffuse correlation spectroscopies in critically brain-injured adults.” Neurocritical care 12 (2010): 1… [cited by applicant]
Mesquita, Rickson C., et al. “Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex.” Journal of Biomedical Optics 18.6 (2013): 067006-067006. [cited by applicant]
Binzoni, Tiziano, et al. “Depth sensitivity of frequency domain optical measurements in diffusive media.” Biomedical optics express 8.6 (2017): 2990-3004. [cited by applicant]
Bevilacqua, Frédéric, et al. “Sampling tissue volumes using frequency-domain photon migration.” Physical Review E 69.5 (2004): 051908. [cited by applicant]
Borycki, Dawid, Oybek Kholiqov, and Vivek J. Srinivasan. “Interferometric near-infrared spectroscopy directly quantifies optical field dynamics in turbid media.” Optica 3.12 (2016): 1471-1476. [cited by applicant]
Buckley, Erin M., et al. “Diffuse correlation spectroscopy for measurement of cerebral blood flow: future prospects.” Neurophotonics 1.1 (2014): 011009-011009. [cited by applicant]
Borycki, Dawid, Oybek Kholiqov, and Vivek J. Srinivasan. “Reflectance-mode interferometric near-infrared spectroscopy quantifies brain absorption, scattering, and blood flow index in vivo.” Optics letters 42.3 (2017): 5… [cited by applicant]
Petoukhova, Anna L., Wiendelt Steenbergen, and Frits FM De Mul. “Path-length distribution and path-length-resolved Doppler measurements of multiply scattered photons by use of low-coherence interferometry.” Optics lette… [cited by applicant]
Baker, Wesley B., et al. “Modified Beer-Lambert law for blood flow.” Biomedical optics express 5.11 (2014): 4053-4075. [cited by applicant]
Durduran, Turgut, et al. “Diffuse optics for tissue monitoring and tomography.” Reports on progress in physics 73.7 (2010): 076701. [cited by applicant]
Tamborini, Davide, et al. “Portable system for time-domain diffuse correlation spectroscopy.” IEEE Transactions on Biomedical Engineering 66.11 (2019): 3014-3025. [cited by applicant]
Cheng, Xiaojun, et al. “Time domain diffuse correlation spectroscopy: modeling the effects of laser coherence length and instrument response function.” Optics letters 43.12 (2018): 2756-2759. [cited by applicant]
Mei, Liang, Gabriel Somesfalean, and Sune Svanberg. “Frequency-modulated light scattering interferometry employed for optical properties and dynamics studies of turbid media.” Biomedical Optics Express 5.8 (2014): 2810-… [cited by applicant]
Boas, David, Jason Sutin, and Maria Angela Franceschini. “Systems and methods for path length selected diffuse correlation spectroscopy.” U.S. Appl. No. 16/079,881. [cited by applicant]
Sutin, Jason, et al. “Systems and methods for time-resolved diffuse correlation spectroscopy.”. [cited by applicant]
CNIPA Office Action dated Aug. 16, 2025, Chinese patent application 2021800676347, 16 pages. [cited by applicant]