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Matlis GC, Zhang Q, Benson EJ, Weeks MK, Andersen K, Jahnavi J, Lafontant A, Breimann J, Hallowell T, Lin Y, Licht DJ, Yodh AG, Kilbaugh TJ, Forti RM, White BR, Baker WB, Xiao R, Ko TS. Chassis-based fiber-coupled optical probe design for reproducible quantitative diffuse optical spectroscopy measurements. PLoS One 2024; 19:e0305254. [PMID: 39052686 PMCID: PMC11271963 DOI: 10.1371/journal.pone.0305254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 05/27/2024] [Indexed: 07/27/2024] Open
Abstract
Advanced optical neuromonitoring of cerebral hemodynamics with hybrid diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS) methods holds promise for non-invasive characterization of brain health in critically ill patients. However, the methods' fiber-coupled patient interfaces (probes) are challenging to apply in emergent clinical scenarios that require rapid and reproducible attachment to the head. To address this challenge, we developed a novel chassis-based optical probe design for DOS/DCS measurements and validated its measurement accuracy and reproducibility against conventional, manually held measurements of cerebral hemodynamics in pediatric swine (n = 20). The chassis-based probe design comprises a detachable fiber housing which snaps into a 3D-printed, circumferential chassis piece that is secured to the skin. To validate its reproducibility, eight measurement repetitions of cerebral tissue blood flow index (BFI), oxygen saturation (StO2), and oxy-, deoxy- and total hemoglobin concentration were acquired at the same demarcated measurement location for each pig. The probe was detached after each measurement. Of the eight measurements, four were acquired by placing the probe into a secured chassis, and four were visually aligned and manually held. We compared the absolute value and intra-subject coefficient of variation (CV) of chassis versus manual measurements. No significant differences were observed in either absolute value or CV between chassis and manual measurements (p > 0.05). However, the CV for BFI (mean ± SD: manual, 19.5% ± 9.6; chassis, 19.0% ± 10.8) was significantly higher than StO2 (manual, 5.8% ± 6.7; chassis, 6.6% ± 7.1) regardless of measurement methodology (p<0.001). The chassis-based DOS/DCS probe design facilitated rapid probe attachment/re-attachment and demonstrated comparable accuracy and reproducibility to conventional, manual alignment. In the future, this design may be adapted for clinical applications to allow for non-invasive monitoring of cerebral health during pediatric critical care.
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Affiliation(s)
- Giselle C. Matlis
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Qihuang Zhang
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, United States of America
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
| | - Emilie J. Benson
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, United States of America
| | - M. Katie Weeks
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Kristen Andersen
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Jharna Jahnavi
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Alec Lafontant
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Jake Breimann
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Thomas Hallowell
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Yuxi Lin
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Daniel J. Licht
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States of America
- Division of Neurology, Department of Pediatrics, Children’s National, Washington, District of Columbia, United States of America
- Division of Neurology, George Washington University, Washington, District of Columbia, United States of America
| | - Arjun G. Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Todd J. Kilbaugh
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States of America
| | - Rodrigo M. Forti
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Brian R. White
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States of America
- Division of Pediatric Cardiology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Wesley B. Baker
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States of America
| | - Rui Xiao
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, United States of America
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States of America
| | - Tiffany S. Ko
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
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Huang YX, Mahler S, Dickson M, Abedi A, Tyszka JM, Lo YT, Russin J, Liu C, Yang C. Compact and cost-effective laser-powered speckle contrast optical spectroscopy fiber-free device for measuring cerebral blood flow. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:067001. [PMID: 38826808 PMCID: PMC11140771 DOI: 10.1117/1.jbo.29.6.067001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/22/2024] [Accepted: 05/15/2024] [Indexed: 06/04/2024]
Abstract
Significance In the realm of cerebrovascular monitoring, primary metrics typically include blood pressure, which influences cerebral blood flow (CBF) and is contingent upon vessel radius. Measuring CBF noninvasively poses a persistent challenge, primarily attributed to the difficulty of accessing and obtaining signal from the brain. Aim Our study aims to introduce a compact speckle contrast optical spectroscopy device for noninvasive CBF measurements at long source-to-detector distances, offering cost-effectiveness, and scalability while tracking blood flow (BF) with remarkable sensitivity and temporal resolution. Approach The wearable sensor module consists solely of a laser diode and a board camera. It can be easily placed on a subject's head to measure BF at a sampling rate of 80 Hz. Results Compared to the single-fiber-based version, the proposed device achieved a signal gain of about 70 times, showed superior stability, reproducibility, and signal-to-noise ratio for measuring BF at long source-to-detector distances. The device can be distributed in multiple configurations around the head. Conclusions Given its cost-effectiveness, scalability, and simplicity, this laser-centric tool offers significant potential in advancing noninvasive cerebral monitoring technologies.
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Affiliation(s)
- Yu Xi Huang
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
| | - Simon Mahler
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
| | - Maya Dickson
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
| | - Aidin Abedi
- University of Southern California, USC Neurorestoration Center, Department of Neurological Surgery, Los Angeles, California, United States
| | - Julian Michael Tyszka
- California Institute of Technology, Division of Humanities and Social Sciences, Pasadena, California, United States
| | - Yu Tung Lo
- University of Southern California, USC Neurorestoration Center, Department of Neurological Surgery, Los Angeles, California, United States
| | - Jonathan Russin
- University of Southern California, USC Neurorestoration Center, Department of Neurological Surgery, Los Angeles, California, United States
- Rancho Los Amigos National Rehabilitation Center, Downey, California, United States
| | - Charles Liu
- University of Southern California, USC Neurorestoration Center, Department of Neurological Surgery, Los Angeles, California, United States
- Rancho Los Amigos National Rehabilitation Center, Downey, California, United States
| | - Changhuei Yang
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
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Sahani P, Nabana S, Okatani T, Inomata N, Kanamori Y. Pixelated gradient thickness optical filter for visible light spectroscopy. APPLIED OPTICS 2024; 63:3537-3546. [PMID: 38856539 DOI: 10.1364/ao.519521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/05/2024] [Indexed: 06/11/2024]
Abstract
A miniature low-cost pixelated gradient thickness optical filter is proposed to achieve spectroscopy in the visible wavelength range. The optical filter consists of a two-dimensional array of metal-dielectric-metal thin films arranged in Fabry-Pérot filter configurations with discretely varying cavity thicknesses. The wavelength-selective characterization of each filter is performed by measuring the transmittance over the visible wavelength range. The pixelated gradient thickness filter is equipped with a CMOS image sensor, and its performance as a spectroscopic module is evaluated by illuminating different monochromatic wavelengths on it. The target spectra are successfully reconstructed from the output signals recorded in the sensor from the respective pixelated gradient thickness filters. The technological competence of the proposed filter will enable its use in handheld devices to widen its application range in day-to-day life.
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Cheng X, Sun S, Xiao Y, Li W, Li J, Yu J, Guo H. Fluorescence molecular tomography based on an online maximum a posteriori estimation algorithm. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2024; 41:844-851. [PMID: 38856571 DOI: 10.1364/josaa.519667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 03/25/2024] [Indexed: 06/11/2024]
Abstract
Fluorescence molecular tomography (FMT) is a non-invasive, radiation-free, and highly sensitive optical molecular imaging technique for early tumor detection. However, inadequate measurement information along with significant scattering of near-infrared light within the tissue leads to high ill-posedness in the inverse problem of FMT. To improve the quality and efficiency of FMT reconstruction, we build a reconstruction model based on log-sum regularization and introduce an online maximum a posteriori estimation (OPE) algorithm to solve the non-convex optimization problem. The OPE algorithm approximates a stationary point by evaluating the gradient of the objective function at each iteration, and its notable strength lies in the remarkable speed of convergence. The results of simulations and experiments demonstrate that the OPE algorithm ensures good reconstruction quality and exhibits outstanding performance in terms of reconstruction efficiency.
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Nolte DD. Coherent light scattering from cellular dynamics in living tissues. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:036601. [PMID: 38433567 DOI: 10.1088/1361-6633/ad2229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/24/2024] [Indexed: 03/05/2024]
Abstract
This review examines the biological physics of intracellular transport probed by the coherent optics of dynamic light scattering from optically thick living tissues. Cells and their constituents are in constant motion, composed of a broad range of speeds spanning many orders of magnitude that reflect the wide array of functions and mechanisms that maintain cellular health. From the organelle scale of tens of nanometers and upward in size, the motion inside living tissue is actively driven rather than thermal, propelled by the hydrolysis of bioenergetic molecules and the forces of molecular motors. Active transport can mimic the random walks of thermal Brownian motion, but mean-squared displacements are far from thermal equilibrium and can display anomalous diffusion through Lévy or fractional Brownian walks. Despite the average isotropic three-dimensional environment of cells and tissues, active cellular or intracellular transport of single light-scattering objects is often pseudo-one-dimensional, for instance as organelle displacement persists along cytoskeletal tracks or as membranes displace along the normal to cell surfaces, albeit isotropically oriented in three dimensions. Coherent light scattering is a natural tool to characterize such tissue dynamics because persistent directed transport induces Doppler shifts in the scattered light. The many frequency-shifted partial waves from the complex and dynamic media interfere to produce dynamic speckle that reveals tissue-scale processes through speckle contrast imaging and fluctuation spectroscopy. Low-coherence interferometry, dynamic optical coherence tomography, diffusing-wave spectroscopy, diffuse-correlation spectroscopy, differential dynamic microscopy and digital holography offer coherent detection methods that shed light on intracellular processes. In health-care applications, altered states of cellular health and disease display altered cellular motions that imprint on the statistical fluctuations of the scattered light. For instance, the efficacy of medical therapeutics can be monitored by measuring the changes they induce in the Doppler spectra of livingex vivocancer biopsies.
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Affiliation(s)
- David D Nolte
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, United States of America
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Yu Y, Tian K, Meng W, Guo J, Liu Z. Synchronous filtering method for improving the optical signal-to-noise ratio of a tunable laser based on the Fabry-Pérot interferometer. OPTICS EXPRESS 2024; 32:7574-7582. [PMID: 38439435 DOI: 10.1364/oe.514115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 02/07/2024] [Indexed: 03/06/2024]
Abstract
Optical measurements are closely related to the optical signal-to-noise ratio (OSNR) of the laser, which can be improved using a tunable optical filter (TOF) to suppress frequency noise. For an external-cavity tunable laser with a tuning range larger than the TOF bandwidth, the wavelength at the center of the TOF passband must be varied based on the laser tuning. This study proposes a tunable-laser OSNR-enhancement method based on the Fabry-Pérot (FP) interferometer. The FP signal contains the wavelength information of the swept laser, which can be used to determine the real-time driving voltage of the TOF. Notably, the laser needs to be continuously tunable without mode hopping, and the free spectral range of the FP interferometer must be smaller than the TOF bandwidth.
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Robinson MB, Cheng TY, Renna M, Wu MM, Kim B, Cheng X, Boas DA, Franceschini MA, Carp SA. Comparing the performance potential of speckle contrast optical spectroscopy and diffuse correlation spectroscopy for cerebral blood flow monitoring using Monte Carlo simulations in realistic head geometries. NEUROPHOTONICS 2024; 11:015004. [PMID: 38282721 PMCID: PMC10821780 DOI: 10.1117/1.nph.11.1.015004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/13/2023] [Accepted: 01/08/2024] [Indexed: 01/30/2024]
Abstract
Significance The non-invasive measurement of cerebral blood flow based on diffuse optical techniques has seen increased interest as a research tool for cerebral perfusion monitoring in critical care and functional brain imaging. Diffuse correlation spectroscopy (DCS) and speckle contrast optical spectroscopy (SCOS) are two such techniques that measure complementary aspects of the fluctuating intensity signal, with DCS quantifying the temporal fluctuations of the signal and SCOS quantifying the spatial blurring of a speckle pattern. With the increasing interest in the use of these techniques, a thorough comparison would inform new adopters of the benefits of each technique. Aim We systematically evaluate the performance of DCS and SCOS for the measurement of cerebral blood flow. Approach Monte Carlo simulations of dynamic light scattering in an MRI-derived head model were performed. For both DCS and SCOS, estimates of sensitivity to cerebral blood flow changes, coefficient of variation of the measured blood flow, and the contrast-to-noise ratio of the measurement to the cerebral perfusion signal were calculated. By varying complementary aspects of data collection between the two methods, we investigated the performance benefits of different measurement strategies, including altering the number of modes per optical detector, the integration time/fitting time of the speckle measurement, and the laser source delivery strategy. Results Through comparison across these metrics with simulated detectors having realistic noise properties, we determine several guiding principles for the optimization of these techniques and report the performance comparison between the two over a range of measurement properties and tissue geometries. We find that SCOS outperforms DCS in terms of contrast-to-noise ratio for the cerebral blood flow signal in the ideal case simulated here but note that SCOS requires careful experimental calibrations to ensure accurate measurements of cerebral blood flow. Conclusion We provide design principles by which to evaluate the development of DCS and SCOS systems for their use in the measurement of cerebral blood flow.
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Affiliation(s)
- Mitchell B. Robinson
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
| | - Tom Y. Cheng
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Marco Renna
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
| | - Melissa M. Wu
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Byungchan Kim
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Xiaojun Cheng
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - David A. Boas
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Maria Angela Franceschini
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
| | - Stefan A. Carp
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
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Zhao H, Sathialingam E, Cowdrick KR, Urner T, Lee SY, Bai S, Akbik F, Samuels OB, Kandiah P, Sadan O, Buckley EM. Comparison of diffuse correlation spectroscopy analytical models for measuring cerebral blood flow in adults. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:126005. [PMID: 38107767 PMCID: PMC10723621 DOI: 10.1117/1.jbo.28.12.126005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 10/30/2023] [Accepted: 11/21/2023] [Indexed: 12/19/2023]
Abstract
Significance Although multilayer analytical models have been proposed to enhance brain sensitivity of diffuse correlation spectroscopy (DCS) measurements of cerebral blood flow, the traditional homogeneous model remains dominant in clinical applications. Rigorous in vivo comparison of these analytical models is lacking. Aim We compare the performance of different analytical models to estimate a cerebral blood flow index (CBFi) with DCS in adults. Approach Resting-state data were obtained on a cohort of 20 adult patients with subarachnoid hemorrhage. Data at 1 and 2.5 cm source-detector separations were analyzed with the homogenous, two-layer, and three-layer models to estimate scalp blood flow index and CBFi. The performance of each model was quantified via fitting convergence, fit stability, brain-to-scalp flow ratio (BSR), and correlation with transcranial Doppler ultrasound (TCD) measurements of cerebral blood flow velocity in the middle cerebral artery (MCA). Results The homogeneous model has the highest pass rate (100%), lowest coefficient of variation (CV) at rest (median [IQR] at 1 Hz of 0.18 [0.13, 0.22]), and most significant correlation with MCA blood flow velocities (R s = 0.59 , p = 0.010 ) compared with both the two- and three-layer models. The multilayer model pass rate was significantly correlated with extracerebral layer thicknesses. Discarding datasets with non-physiological BSRs increased the correlation between DCS measured CBFi and TCD measured MCA velocities for all models. Conclusions We found that the homogeneous model has the highest pass rate, lowest CV at rest, and most significant correlation with MCA blood flow velocities. Results from the multilayer models should be taken with caution because they suffer from lower pass rates and higher coefficients of variation at rest and can converge to non-physiological values for CBFi. Future work is needed to validate these models in vivo, and novel approaches are merited to improve the performance of the multimodel models.
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Affiliation(s)
- Hongting Zhao
- Emory University, Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Eashani Sathialingam
- Emory University, Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Kyle R. Cowdrick
- Emory University, Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Tara Urner
- Emory University, Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Seung Yup Lee
- Emory University, Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Kennesaw State University, Department of Electrical and Computer Engineering, Marietta, Georgia, United States
| | - Shasha Bai
- Emory University, School of Medicine, Department of Pediatrics, Atlanta, Georgia, United States
| | - Feras Akbik
- Emory University, School of Medicine, Department of Neurology and Neurosurgery, Division of Neurocritical Care, Atlanta, Georgia, United States
| | - Owen B. Samuels
- Emory University, School of Medicine, Department of Neurology and Neurosurgery, Division of Neurocritical Care, Atlanta, Georgia, United States
| | - Prem Kandiah
- Emory University, School of Medicine, Department of Neurology and Neurosurgery, Division of Neurocritical Care, Atlanta, Georgia, United States
| | - Ofer Sadan
- Emory University, School of Medicine, Department of Neurology and Neurosurgery, Division of Neurocritical Care, Atlanta, Georgia, United States
| | - Erin M. Buckley
- Emory University, Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Emory University, School of Medicine, Department of Pediatrics, Atlanta, Georgia, United States
- Children’s Healthcare of Atlanta, Children’s Research Scholar, Atlanta, Georgia, United States
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Aparanji S, Zhao M, Srinivasan VJ. Decoding diffuse light scattering dynamics in layered tissues: path length versus fluctuation time scale. OPTICS LETTERS 2023; 48:6056-6059. [PMID: 37966788 DOI: 10.1364/ol.507162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 10/31/2023] [Indexed: 11/16/2023]
Abstract
Dynamic multiple light scattering (DMLS) has found numerous applications, including soft matter physics and biomedical optics. Yet biological tissues may have complex internal geometries, presenting a challenge for noninvasive measurements. Deciphering laminar dynamics is crucial to accurately interpret tissue or organ physiology. Seminal DMLS work noted that one can probe deeper layers indirectly by analyzing light fluctuations on shorter time scales. Recent technologies have enabled probing deeper layers directly by analyzing fluctuations at longer path lengths. The following question arises: are the indirect and direct approaches synergistic or redundant? Here, by adding an optical switch to path-length-filtered interferometric diffusing wave spectroscopy, we experimentally address this question in the context of a forearm occlusion study. We find that both approaches afford better distinction of light scattering dynamics in layered tissues than either approach alone. This motivates further development of methods that integrate both decorrelation time scale and light path length to probe layered tissues.
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Cowdrick KR, Akbar M, Boodooram T, Harris LH, Bai S, Brothers RO, Arrington M, Lee SY, Khemani K, Gee B, Buckley EM. Impaired cerebrovascular reactivity in pediatric sickle cell disease using diffuse correlation spectroscopy. BIOMEDICAL OPTICS EXPRESS 2023; 14:5696-5708. [PMID: 38021121 PMCID: PMC10659811 DOI: 10.1364/boe.499274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 12/01/2023]
Abstract
Cerebrovascular reactivity (CVR), defined as the ability of cerebral vasculature to dilate in response to a vasodilatory stimulus, is an integral mechanism in brain homeostasis that is thought to be impaired in sickle cell disease (SCD). This study used diffuse correlation spectroscopy and a simple breath-hold stimulus to quantify CVR non-invasively in a cohort of 12 children with SCD and 14 controls. Median [interquartile range] CVR was significantly decreased in SCD compared to controls (2.03 [1.31, 2.44] versus 3.49 [3.00, 4.11] %/mmHg, p = 0.028). These results suggest DCS may provide a feasible means to routinely monitor CVR impairments in pediatric SCD.
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Affiliation(s)
- Kyle R. Cowdrick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Drive NE, Atlanta, GA 30322, USA
| | - Mariam Akbar
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Drive NE, Atlanta, GA 30322, USA
| | - Tisha Boodooram
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Drive NE, Atlanta, GA 30322, USA
| | - LaBeausha H. Harris
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Drive NE, Atlanta, GA 30322, USA
| | - Shasha Bai
- Pediatric Biostatistics Core, Emory University School of Medicine, 1405 Clifton Road NE, Atlanta, GA 30322, USA
| | - Rowan O. Brothers
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Drive NE, Atlanta, GA 30322, USA
| | - Michael Arrington
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Drive NE, Atlanta, GA 30322, USA
| | - Seung Yup Lee
- Department of Electrical and Computer Engineering, Kennesaw State University, 840 Polytechnic Lane, Marietta, GA 30060, USA
| | - Kirsma Khemani
- Aflac Cancer and Blood Disorders Center, Division of Pediatric Hematology/Oncology, Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA 30322, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Beatrice Gee
- Aflac Cancer and Blood Disorders Center, Division of Pediatric Hematology/Oncology, Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA 30322, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Erin M. Buckley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Drive NE, Atlanta, GA 30322, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
- Children's Research Scholar, Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA 30322, USA
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Huang YX, Mahler S, Mertz J, Yang C. Interferometric speckle visibility spectroscopy (iSVS) for measuring decorrelation time and dynamics of moving samples with enhanced signal-to-noise ratio and relaxed reference requirements. OPTICS EXPRESS 2023; 31:31253-31266. [PMID: 37710649 PMCID: PMC10544958 DOI: 10.1364/oe.499473] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/15/2023] [Accepted: 08/25/2023] [Indexed: 09/16/2023]
Abstract
Diffusing wave spectroscopy (DWS) is a group of techniques used to measure the dynamics of a scattering medium in a non-invasive manner. DWS methods rely on detecting the speckle light field from the moving scattering medium and measuring the speckle decorrelation time to quantify the scattering medium's dynamics. For DWS, the signal-to-noise (SNR) is determined by the ratio between measured decorrelation time to the standard error of the measurement. This SNR is often low in certain applications because of high noise variances and low signal intensity, especially in biological applications with restricted exposure and emission levels. To address this photon-limited signal-to-noise ratio problem, we investigated, theoretically and experimentally, the SNR of an interferometric speckle visibility spectroscopy (iSVS) compared to more traditional DWS methods. We found that iSVS can provide excellent SNR performance through its ability to overcome camera noise. We also proved an iSVS system has more relaxed constraints on the reference beam properties. For an iSVS system to function properly, we only require the reference beam to exhibit local temporal stability, while incident angle, reference phase and intensity uniformity do not need to be constrained. This flexibility can potentially enable more unconventional iSVS implementation schemes.
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Affiliation(s)
- Yu Xi Huang
- Department of Electrical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Simon Mahler
- Department of Electrical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Jerome Mertz
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
| | - Changhuei Yang
- Department of Electrical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Robinson MB, Renna M, Ozana N, Martin AN, Otic N, Carp SA, Franceschini MA. Portable, high speed blood flow measurements enabled by long wavelength, interferometric diffuse correlation spectroscopy (LW-iDCS). Sci Rep 2023; 13:8803. [PMID: 37258644 PMCID: PMC10232495 DOI: 10.1038/s41598-023-36074-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 05/29/2023] [Indexed: 06/02/2023] Open
Abstract
Diffuse correlation spectroscopy (DCS) is an optical technique that can be used to characterize blood flow in tissue. The measurement of cerebral hemodynamics has arisen as a promising use case for DCS, though traditional implementations of DCS exhibit suboptimal signal-to-noise ratio (SNR) and cerebral sensitivity to make robust measurements of cerebral blood flow in adults. In this work, we present long wavelength, interferometric DCS (LW-iDCS), which combines the use of a longer illumination wavelength (1064 nm), multi-speckle, and interferometric detection, to improve both cerebral sensitivity and SNR. Through direct comparison with long wavelength DCS based on superconducting nanowire single photon detectors, we demonstrate an approximate 5× improvement in SNR over a single channel of LW-DCS in the measured blood flow signals in human subjects. We show equivalence of extracted blood flow between LW-DCS and LW-iDCS, and demonstrate the feasibility of LW-iDCS measured at 100 Hz at a source-detector separation of 3.5 cm. This improvement in performance has the potential to enable robust measurement of cerebral hemodynamics and unlock novel use cases for diffuse correlation spectroscopy.
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Affiliation(s)
- Mitchell B Robinson
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
| | - Marco Renna
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Nisan Ozana
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Bar-Ilan University, Tel Aviv District, Ramat Gan, Israel
| | - Alyssa N Martin
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Nikola Otic
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Stefan A Carp
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Maria Angela Franceschini
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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