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Zotov AK, Pushkarev AV, Alekseeva AI, Zaytsev KI, Ryabikin SS, Tsiganov DI, Zhidkov DA, Burkov IA, Kurlov VN, Dolganova IN. Optical Sensing of Tissue Freezing Depth by Sapphire Cryo-Applicator and Steady-State Diffuse Reflectance Analysis. SENSORS (BASEL, SWITZERLAND) 2024; 24:3655. [PMID: 38894444 PMCID: PMC11175356 DOI: 10.3390/s24113655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/31/2024] [Accepted: 06/02/2024] [Indexed: 06/21/2024]
Abstract
This work describes a sapphire cryo-applicator with the ability to sense tissue freezing depth during cryosurgery by illumination of tissue and analyzing diffuse optical signals in a steady-state regime. The applicator was manufactured by the crystal growth technique and has several spatially resolved internal channels for accommodating optical fibers. The method of reconstructing freezing depth proposed in this work requires one illumination and two detection channels. The analysis of the detected intensities yields the estimation of the time evolution of the effective attenuation coefficient, which is compared with the theoretically calculated values obtained for a number of combinations of tissue parameters. The experimental test of the proposed applicator and approach for freezing depth reconstruction was performed using gelatin-based tissue phantom and rat liver tissue in vivo. It revealed the ability to estimate depth up to 8 mm. The in vivo study confirmed the feasibility of the applicator to sense the freezing depth of living tissues despite the possible diversity of their optical parameters. The results justify the potential of the described design of a sapphire instrument for cryosurgery.
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Affiliation(s)
- Arsen K. Zotov
- Osipyan Institute of Solid State Physics of the Russian Academy of Sciences, Chernogolovka 142432, Russia; (A.K.Z.)
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991, Russia
| | - Aleksandr V. Pushkarev
- Bauman Moscow State Technical University, Moscow 105005, Russia
- Federal State Budgetary Educational Institution of Further Professional Education “Russian Medical Academy of Continuous Professional Education”, Ministry of Healthcare of the Russian Federation, Moscow 125993, Russia
| | - Anna I. Alekseeva
- Avtsyn Research Institute of Human Morphology, FSBSI “Petrovsky National Research Centre of Surgery”, Moscow 117418, Russia
| | - Kirill I. Zaytsev
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991, Russia
| | - Sergey S. Ryabikin
- Bauman Moscow State Technical University, Moscow 105005, Russia
- Federal State Budgetary Educational Institution of Further Professional Education “Russian Medical Academy of Continuous Professional Education”, Ministry of Healthcare of the Russian Federation, Moscow 125993, Russia
| | - Dmitry I. Tsiganov
- Bauman Moscow State Technical University, Moscow 105005, Russia
- Federal State Budgetary Educational Institution of Further Professional Education “Russian Medical Academy of Continuous Professional Education”, Ministry of Healthcare of the Russian Federation, Moscow 125993, Russia
| | - Dmitriy A. Zhidkov
- Bauman Moscow State Technical University, Moscow 105005, Russia
- Federal State Budgetary Educational Institution of Further Professional Education “Russian Medical Academy of Continuous Professional Education”, Ministry of Healthcare of the Russian Federation, Moscow 125993, Russia
| | - Ivan A. Burkov
- Bauman Moscow State Technical University, Moscow 105005, Russia
| | - Vladimir N. Kurlov
- Osipyan Institute of Solid State Physics of the Russian Academy of Sciences, Chernogolovka 142432, Russia; (A.K.Z.)
| | - Irina N. Dolganova
- Osipyan Institute of Solid State Physics of the Russian Academy of Sciences, Chernogolovka 142432, Russia; (A.K.Z.)
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Martelli F, Pifferi A, Farina A, Amendola C, Maffeis G, Tommasi F, Cavalieri S, Spinelli L, Torricelli A. Statistics of maximum photon penetration depth in a two-layer diffusive medium. BIOMEDICAL OPTICS EXPRESS 2024; 15:1163-1180. [PMID: 38404319 PMCID: PMC10890894 DOI: 10.1364/boe.507294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/30/2023] [Accepted: 12/20/2023] [Indexed: 02/27/2024]
Abstract
We present numerical results for the probability density function f(z) and for the mean value of photon maximum penetration depth ‹zmax› in a two-layer diffusive medium. Both time domain and continuous wave regime are considered with several combinations of the optical properties (absorption coefficient, reduced scattering coefficient) of the two layers, and with different geometrical configurations (source detector distance, thickness of the upper layer). Practical considerations on the design of time domain and continuous wave systems are derived. The methods and the results are of interest for many research fields such as biomedical optics and advanced microscopy.
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Affiliation(s)
- Fabrizio Martelli
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Sesto Fiorentino, Firenze, Italy
| | - Antonio Pifferi
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milan, Italy
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milan, Italy
| | | | - Giulia Maffeis
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
| | - Federico Tommasi
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Sesto Fiorentino, Firenze, Italy
| | - Stefano Cavalieri
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Sesto Fiorentino, Firenze, Italy
| | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milan, Italy
| | - Alessandro Torricelli
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milan, Italy
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Fernandez C, Blaney G, Frias J, Tavakoli F, Sassaroli A, Fantini S. Single-distance and dual-slope frequency-domain near-infrared spectroscopy to assess skeletal muscle hemodynamics. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:125004. [PMID: 38098980 PMCID: PMC10720738 DOI: 10.1117/1.jbo.28.12.125004] [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: 07/11/2023] [Revised: 10/19/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023]
Abstract
Significance Non-invasive optical measurements of deep tissue (e.g., muscle) need to take into account confounding contributions from baseline and dynamic optical properties of superficial tissue (adipose tissue). Aim Discriminate superficial and deep tissue hemodynamics using data collected with frequency-domain (FD) near-infrared spectroscopy (NIRS) in a dual-slope (DS) configuration. Approach Experimental data were collected in vivo on the forearm of three human subjects during a 3-min arterial occlusion or 1-min venous occlusion. Theoretical data were generated using diffusion theory for two-layered media with varying values of the reduced scattering coefficient (μ s ' ) (range: 0.5 to 1.1 mm - 1 ) and absorption coefficient (μ a ) (range: 0.005 - 0.015 mm - 1 ) of the two layers, and top layer thickness (range: 2 to 8 mm). Data were analyzed using diffusion theory for a homogeneous semi-infinite medium. Results Experimental data in vivo were consistent with simulated data for a two-layered medium with a larger μ s ' in the top layer, comparable absorption changes in the top and bottom layers during venous occlusion, and smaller absorption changes in the top vs. bottom layers during arterial occlusion. Conclusions The dataset generated by DS FD-NIRS may allow for discrimination of superficial and deep absorption changes in two-layered media, thus lending itself to individual measurements of hemodynamics in adipose and muscle tissue.
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Affiliation(s)
- Cristianne Fernandez
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - Giles Blaney
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - Jodee Frias
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - Fatemeh Tavakoli
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - Sergio Fantini
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
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Sudakou A, Wabnitz H, Liemert A, Wolf M, Liebert A. Two-layered blood-lipid phantom and method to determine absorption and oxygenation employing changes in moments of DTOFs. BIOMEDICAL OPTICS EXPRESS 2023; 14:3506-3531. [PMID: 37497481 PMCID: PMC10368065 DOI: 10.1364/boe.492168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/29/2023] [Accepted: 05/29/2023] [Indexed: 07/28/2023]
Abstract
Near-infrared spectroscopy (NIRS) is an established technique for measuring tissue oxygen saturation (StO2), which is of high clinical value. For tissues that have layered structures, it is challenging but clinically relevant to obtain StO2 of the different layers, e.g. brain and scalp. For this aim, we present a new method of data analysis for time-domain NIRS (TD-NIRS) and a new two-layered blood-lipid phantom. The new analysis method enables accurate determination of even large changes of the absorption coefficient (Δµa) in multiple layers. By adding Δµa to the baseline µa, this method provides absolute µa and hence StO2 in multiple layers. The method utilizes (i) changes in statistical moments of the distributions of times of flight of photons (DTOFs), (ii) an analytical solution of the diffusion equation for an N-layered medium, (iii) and the Levenberg-Marquardt algorithm (LMA) to determine Δµa in multiple layers from the changes in moments. The method is suitable for NIRS tissue oximetry (relying on µa) as well as functional NIRS (fNIRS) applications (relying on Δµa). Experiments were conducted on a new phantom, which enabled us to simulate dynamic StO2 changes in two layers for the first time. Two separate compartments, which mimic superficial and deep layers, hold blood-lipid mixtures that can be deoxygenated (using yeast) and oxygenated (by bubbling oxygen) independently. Simultaneous NIRS measurements can be performed on the two-layered medium (variable superficial layer thickness, L), the deep (homogeneous), and/or the superficial (homogeneous). In two experiments involving ink, we increased the nominal µa in one of two compartments from 0.05 to 0.25 cm-1, L set to 14.5 mm. In three experiments involving blood (L set to 12, 15, or 17 mm), we used a protocol consisting of six deoxygenation cycles. A state-of-the-art multi-wavelength TD-NIRS system measured simultaneously on the two-layered medium, as well as on the deep compartment for a reference. The new method accurately determined µa (and hence StO2) in both compartments. The method is a significant progress in overcoming the contamination from the superficial layer, which is beneficial for NIRS and fNIRS applications, and may improve the determination of StO2 in the brain from measurements on the head. The advanced phantom may assist in the ongoing effort towards more realistic standardized performance tests in NIRS tissue oximetry. Data and MATLAB codes used in this study were made publicly available.
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Affiliation(s)
- Aleh Sudakou
- Nałęcz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - André Liemert
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Germany
| | - Martin Wolf
- Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Adam Liebert
- Nałęcz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
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Forti RM, Hobson LJ, Benson EJ, Ko TS, Ranieri NR, Laurent G, Weeks MK, Widmann NJ, Morton S, Davis AM, Sueishi T, Lin Y, Wulwick KS, Fagan N, Shin SS, Kao SH, Licht DJ, White BR, Kilbaugh TJ, Yodh AG, Baker WB. Non-invasive diffuse optical monitoring of cerebral physiology in an adult swine-model of impact traumatic brain injury. BIOMEDICAL OPTICS EXPRESS 2023; 14:2432-2448. [PMID: 37342705 PMCID: PMC10278631 DOI: 10.1364/boe.486363] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/17/2023] [Accepted: 04/12/2023] [Indexed: 06/23/2023]
Abstract
In this study, we used diffuse optics to address the need for non-invasive, continuous monitoring of cerebral physiology following traumatic brain injury (TBI). We combined frequency-domain and broadband diffuse optical spectroscopy with diffuse correlation spectroscopy to monitor cerebral oxygen metabolism, cerebral blood volume, and cerebral water content in an established adult swine-model of impact TBI. Cerebral physiology was monitored before and after TBI (up to 14 days post injury). Overall, our results suggest that non-invasive optical monitoring can assess cerebral physiologic impairments post-TBI, including an initial reduction in oxygen metabolism, development of cerebral hemorrhage/hematoma, and brain swelling.
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Affiliation(s)
- Rodrigo M. Forti
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
| | - Lucas J. Hobson
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emilie J. Benson
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tiffany S. Ko
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicolina R. Ranieri
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
| | - Gerard Laurent
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
| | - M. Katie Weeks
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicholas J. Widmann
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sarah Morton
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Anthony M. Davis
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Takayuki Sueishi
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yuxi Lin
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Karli S. Wulwick
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicholas Fagan
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Samuel S. Shin
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shih-Han Kao
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Daniel J. Licht
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brian R. White
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Division of Cardiology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Todd J. Kilbaugh
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arjun G. Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wesley B. Baker
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Dolganova IN, Zotov AK, Safonova LP, Aleksandrova PV, Reshetov IV, Zaytsev KI, Tuchin VV, Kurlov VN. Feasibility test of a sapphire cryoprobe with optical monitoring of tissue freezing. JOURNAL OF BIOPHOTONICS 2023; 16:e202200288. [PMID: 36510652 DOI: 10.1002/jbio.202200288] [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: 09/19/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
This article describes a sapphire cryoprobe as a promising solution to the significant problem of modern cryosurgery that is the monitoring of tissue freezing. This probe consists of a sapphire rod manufactured by the edge-defined film-fed growth technique from Al2 O3 melt and optical fibers accommodated inside the rod and connected to the source and the detector. The probe's design enables detection of spatially resolved diffuse reflected intensities of tissue optical response, which are used for the estimation of tissue freezing depth. The current type of the 12.5-mm diameter sapphire probe cooled down by the liquid nitrogen assumes a superficial cryoablation. The experimental test made by using a gelatin-intralipid tissue phantom shows the feasibility of such concept, revealing the capabilities of monitoring the freezing depth up to 10 mm by the particular instrumentation realization of the probe. This justifies a potential of sapphire-based instruments aided by optical diagnosis in modern cryosurgery.
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Affiliation(s)
- Irina N Dolganova
- Osipyan Institute of Solid State Physics of the Russian Academy of Sciences, Chernogolovka, Russia
| | - Arsen K Zotov
- Osipyan Institute of Solid State Physics of the Russian Academy of Sciences, Chernogolovka, Russia
| | | | - Polina V Aleksandrova
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
| | - Igor V Reshetov
- Institute for Cluster Oncology, Sechenov University, Moscow, Russia
| | - Kirill I Zaytsev
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
| | - Valery V Tuchin
- Science Medical Center, Saratov State University, Saratov, Russia
- Institute of Precision Mechanics and Control, FRC "Saratov Scientific Centre of the Russian Academy of Sciences", Saratov, Russia
- Tomsk State University, Tomsk, Russia
| | - Vladimir N Kurlov
- Osipyan Institute of Solid State Physics of the Russian Academy of Sciences, Chernogolovka, Russia
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Efficient computation of the steady-state and time-domain solutions of the photon diffusion equation in layered turbid media. Sci Rep 2022; 12:18979. [PMID: 36347893 PMCID: PMC9643457 DOI: 10.1038/s41598-022-22649-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
Accurate and efficient forward models of photon migration in heterogeneous geometries are important for many applications of light in medicine because many biological tissues exhibit a layered structure of independent optical properties and thickness. However, closed form analytical solutions are not readily available for layered tissue-models, and often are modeled using computationally expensive numerical techniques or theoretical approximations that limit accuracy and real-time analysis. Here, we develop an open-source accurate, efficient, and stable numerical routine to solve the diffusion equation in the steady-state and time-domain for a layered cylinder tissue model with an arbitrary number of layers and specified thickness and optical coefficients. We show that the steady-state ([Formula: see text] ms) and time-domain ([Formula: see text] ms) fluence (for an 8-layer medium) can be calculated with absolute numerical errors approaching machine precision. The numerical implementation increased computation speed by 3 to 4 orders of magnitude compared to previously reported theoretical solutions in layered media. We verify our solutions asymptotically to homogeneous tissue geometries using closed form analytical solutions to assess convergence and numerical accuracy. Approximate solutions to compute the reflected intensity are presented which can decrease the computation time by an additional 2-3 orders of magnitude. We also compare our solutions for 2, 3, and 5 layered media to gold-standard Monte Carlo simulations in layered tissue models of high interest in biomedical optics (e.g. skin/fat/muscle and brain). The presented routine could enable more robust real-time data analysis tools in heterogeneous tissues that are important in many clinical applications such as functional brain imaging and diffuse optical spectroscopy.
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8
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Non-invasive monitoring of blood oxygenation in human placentas via concurrent diffuse optical spectroscopy and ultrasound imaging. Nat Biomed Eng 2022; 6:1017-1030. [PMID: 35970929 PMCID: PMC9944515 DOI: 10.1038/s41551-022-00913-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 06/27/2022] [Indexed: 01/13/2023]
Abstract
Direct assessment of blood oxygenation in the human placenta can provide information about placental function. However, the monitoring of placental oxygenation involves invasive sampling or imaging techniques that are poorly suited for bedside use. Here we show that placental oxygen haemodynamics can be non-invasively probed in real time and up to 4.2 cm below the body surface via concurrent frequency-domain diffuse optical spectroscopy and ultrasound imaging. We developed a multimodal instrument to facilitate the assessment of the properties of the anterior placenta by leveraging image-reconstruction algorithms that integrate ultrasound information about the morphology of tissue layers with optical information on haemodynamics. In a pilot investigation involving placentas with normal function (15 women) or abnormal function (9 women) from pregnancies in the third trimester, we found no significant differences in baseline haemoglobin properties, but statistically significant differences in the haemodynamic responses to maternal hyperoxia. Our findings suggest that the non-invasive monitoring of placental oxygenation may aid the early detection of placenta-related adverse pregnancy outcomes and maternal vascular malperfusion.
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9
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Kao TC, Sung KB. Quantifying tissue optical properties of human heads in vivo using continuous-wave near-infrared spectroscopy and subject-specific three-dimensional Monte Carlo models. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:083021. [PMID: 35733242 PMCID: PMC9214577 DOI: 10.1117/1.jbo.27.8.083021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Quantifying subject-specific optical properties (OPs) including absorption and transport scattering coefficients of tissues in the human head could improve the modeling of photon propagation for the analysis of functional near-infrared spectroscopy (fNIRS) data and dosage quantification in therapeutic applications. Current methods employ diffuse approximation, which excludes a low-scattering cerebrospinal fluid compartment and causes errors. AIM This work aims to quantify OPs of the scalp, skull, and gray matter in vivo based on accurate Monte Carlo (MC) modeling. APPROACH Iterative curve fitting was applied to quantify tissue OPs from multidistance continuous-wave NIR reflectance spectra. An artificial neural network (ANN) was trained using MC-simulated reflectance values based on subject-specific voxel-based tissue models to replace MC simulations as the forward model in curve fitting. To efficiently generate sufficient data for training the ANN, the efficiency of MC simulations was greatly improved by white MC simulations, increasing the detectors' acceptance angle, and building a lookup table for interpolation. RESULTS The trained ANN was six orders of magnitude faster than the original MC simulations. OPs of the three tissue compartments were quantified from NIR reflectance spectra measured at the forehead of five healthy subjects and their uncertainties were estimated. CONCLUSIONS This work demonstrated an MC-based iterative curve fitting method to quantify subject-specific tissue OPs in-vivo, with all OPs except for scattering coefficients of scalp within the ranges reported in the literature, which could aid the modeling of photon propagation in human heads.
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Affiliation(s)
- Tzu-Chia Kao
- National Taiwan University, Graduate Institute of Biomedical Electronics and Bioinformatics, Taipei, Taiwan
| | - Kung-Bin Sung
- National Taiwan University, Graduate Institute of Biomedical Electronics and Bioinformatics, Taipei, Taiwan
- National Taiwan University, Department of Electrical Engineering, Taipei, Taiwan
- National Taiwan University, Molecular Imaging Center, Taipei, Taiwan
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10
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Maria A, Hirvi P, Kotilahti K, Heiskala J, Tuulari JJ, Karlsson L, Karlsson H, Nissilä I. Imaging affective and non-affective touch processing in two-year-old children. Neuroimage 2022; 251:118983. [PMID: 35149231 DOI: 10.1016/j.neuroimage.2022.118983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 12/22/2021] [Accepted: 02/07/2022] [Indexed: 10/19/2022] Open
Abstract
Touch is an important component of early parent-child interaction and plays a critical role in the socio-emotional development of children. However, there are limited studies on touch processing amongst children in the age range from one to three years. The present study used frequency-domain diffuse optical tomography (DOT) to investigate the processing of affective and non-affective touch over left frontotemporal brain areas contralateral to the stimulated forearm in two-year-old children. Affective touch was administered by a single stroke with a soft brush over the child's right dorsal forearm at 3 cm/s, while non-affective touch was provided by multiple brush strokes at 30 cm/s. We found that in the insula, the total haemoglobin (HbT) response to slow brushing was significantly greater than the response to fast brushing (slow > fast). Additionally, a region in the postcentral gyrus, Rolandic operculum and superior temporal gyrus exhibited greater response to fast brushing than slow brushing (fast > slow). These findings confirm that an adult-like pattern of haemodynamic responses to affective and non-affective touch can be recorded in two-year-old subjects using DOT. To improve the accuracy of modelling light transport in the two-year-old subjects, we used a published age-appropriate atlas and deformed it to match the exterior shape of each subject's head. We estimated the combined scalp and skull, and grey matter (GM) optical properties by fitting simulated data to calibrated and coupling error corrected phase and amplitude measurements. By utilizing a two-compartment cerebrospinal fluid (CSF) model, the accuracy of estimation of GM optical properties and the localization of activation in the insula was improved. The techniques presented in this paper can be used to study neural development of children at different ages and illustrate that the technology is well-tolerated by most two-year-old children and not excessively sensitive to subject movement. The study points the way towards exciting possibilities in functional imaging of deeper functional areas near sulci in small children.
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Affiliation(s)
- Ambika Maria
- University of Turku, Department of Clinical Medicine, Turku Brain and Mind Center, FinnBrain Birth Cohort Study, Finland; University of Turku and Turku University Hospital, Department of Psychiatry, Finland
| | - Pauliina Hirvi
- Aalto University, Department of Neuroscience and Biomedical Engineering, P.O. Box 12200, AALTO FI-00076, Finland; Aalto University, Department of Mathematics and Systems Analysis, Finland
| | - Kalle Kotilahti
- Aalto University, Department of Neuroscience and Biomedical Engineering, P.O. Box 12200, AALTO FI-00076, Finland; University of Turku, Department of Clinical Medicine, Turku Brain and Mind Center, FinnBrain Birth Cohort Study, Finland
| | - Juha Heiskala
- HUS Medical Imaging Center, Clinical Neurophysiology; Clinical Neurosciences, Helsinki, University Hospital and University of Helsinki, Helsinki, Finland
| | - Jetro J Tuulari
- University of Turku, Department of Clinical Medicine, Turku Brain and Mind Center, FinnBrain Birth Cohort Study, Finland; University of Turku and Turku University Hospital, Department of Psychiatry, Finland; Turku Collegium for Science, Medicine and Technology, TCSMT, University of Turku, Finland
| | - Linnea Karlsson
- University of Turku, Department of Clinical Medicine, Turku Brain and Mind Center, FinnBrain Birth Cohort Study, Finland; University of Turku and Turku University Hospital, Department of Psychiatry, Finland; University of Turku and Turku University Hospital, Department of Paediatrics and Adolescent Medicine, Finland; Centre for Population Health Research, Turku University Hospital and University of Turku, Turku, Finland
| | - Hasse Karlsson
- University of Turku, Department of Clinical Medicine, Turku Brain and Mind Center, FinnBrain Birth Cohort Study, Finland; University of Turku and Turku University Hospital, Department of Psychiatry, Finland
| | - Ilkka Nissilä
- Aalto University, Department of Neuroscience and Biomedical Engineering, P.O. Box 12200, AALTO FI-00076, Finland.
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11
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Rudraiah PS, Duadi H, Fixler D. Bottom layer absorption coefficients extraction from two-layer phantoms based on crossover point in diffuse reflectance. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210253R. [PMID: 34850612 PMCID: PMC8630471 DOI: 10.1117/1.jbo.26.11.117001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Numerous optical imaging and spectroscopy techniques are used to study the tissue-optical properties; the majority of them are limited in information regarding the penetration depth. A simple, safe, easily applicable diagnostic technique is required to get deeper tissue information in a multilayer structure. AIM A fiber-based diffuse reflectance (DR) technique is used to extract and quantify the bottom layer absorption coefficients in two-layer (2L) tissue-mimicking solid phantoms. We determine the Indian black ink concentrations in a deep-hidden layer that is sandwiched between agar and silicone-based phantom layers. APPROACH A fiber-based DR experiment was performed to study the optical properties of the tissue at higher penetration depth, with different fiber core diameters and a constant numerical aperture (0.5 NA). The optimal core diameter of the fiber was chosen by measuring solid phantoms. In 2L phantoms, the thickness of the top layer was kept 5.5 mm with a constant absorption and reduced scattering coefficients (μa = 0.045 mm - 1 and μs ' = 2.622 mm - 1), whereas the absorption coefficients of the bottom layers were varied from 0.014 to 0.037 mm - 1 keeping the μs ' the same as the top layer. A unique crossover point (Cp) was found in the DR intensity profile against distance. We examined the slope before and after the Cp. These two slopes indicate the difference between the optical properties of the top and bottom layers. Our technique got further verification, as we successfully determined the Cp with different Indian black ink concentrations, placed at the junction between the agar and silicone-based phantom layers. RESULTS The DR measurements were applied to 2L phantoms. Two different slopes were found in 2L phantoms compared to the one-layer (optical properties equal to the top layer of 2L). We extracted the slopes before and after the Cp in the 2L phantoms. The calculated absorption coefficients before the Cp were 0.014 ± 0.0004, 0.022 ± 0.0003, 0.028 ± 0.0003, and 0.036 ± 0.0014 mm - 1, and the absorption coefficients after the Cp were 0.019 ± 0.0013, 0.013 ± 0.0004, 0.014 ± 0.0006, and 0.031 ± 0.0001 mm - 1, respectively. The calculated absorption coefficients before the Cp were in good agreement with the optical properties of the bottom layer. The calculated absorption coefficients after the Cp were not the same as the top layer. Our DR system successfully determines the crossover points 12.14 ± 0.11 and 11.73 ± 0.15 mm for 70% and 100% ink concentrations placed at the junction of the agar and silicone layers. CONCLUSIONS In a 2L tissue structure, the Cp depends on the absorption coefficients of top and bottom layers and the thickness of the top layer. With the help of the Cp and the absorption coefficients, one can determine the thickness of the top layer or vice versa. The slope value before the Cp in the DR profile allowed us to determine the absorption properties of the bottom layer instead of having the average behavior of the 2L phantom in the far detection range (11.0 to 17.0 mm).
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Affiliation(s)
- Pavitra S. Rudraiah
- Bar Ilan University, Faculty of Engineering and Institute of Nanotechnology and Advanced Materials, Ramat Gan, Israel
| | - Hamootal Duadi
- Bar Ilan University, Faculty of Engineering and Institute of Nanotechnology and Advanced Materials, Ramat Gan, Israel
| | - Dror Fixler
- Bar Ilan University, Faculty of Engineering and Institute of Nanotechnology and Advanced Materials, Ramat Gan, Israel
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12
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Zhao H, Sathialingam E, Buckley EM. Accuracy of diffuse correlation spectroscopy measurements of cerebral blood flow when using a three-layer analytical model. BIOMEDICAL OPTICS EXPRESS 2021; 12:7149-7161. [PMID: 34858706 PMCID: PMC8606134 DOI: 10.1364/boe.438303] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/15/2021] [Accepted: 10/15/2021] [Indexed: 05/06/2023]
Abstract
Diffuse correlation spectroscopy (DCS) is a non-invasive optical technology for the assessment of an index of cerebral blood flow (CBFi). Analytical methods that model the head as a three-layered medium (i.e., scalp, skull, brain) are becoming more commonly used to minimize the contribution of extracerebral layers to the measured DCS signal in adult cerebral blood flow studies. However, these models rely on a priori knowledge of layer optical properties and thicknesses. Errors in these values can lead to errors in the estimation of CBFi, although the magnitude of this influence has not been rigorously characterized. Herein, we investigate the accuracy of measuring cerebral blood flow with a three-layer model when errors in layer optical properties or thicknesses are present. Through a series of in silico experiments, we demonstrate that CBFi is highly sensitive to errors in brain optical properties and skull and scalp thicknesses. Relative changes in CBFi are less sensitive to optical properties but are influenced by errors in layer thickness. Thus, when using the three-layer model, accurate estimation of scalp and skull thickness are required for reliable results.
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Affiliation(s)
- Hongting Zhao
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Dr. NE, Atlanta, GA 30322, USA
| | - Eashani Sathialingam
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Dr. NE, Atlanta, GA 30322, USA
| | - Erin M. Buckley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 1760 Haygood Dr. NE, Atlanta, GA 30322, USA
- Department of Pediatrics, Emory University School of Medicine, 2015 Uppergate Dr., Atlanta, GA 30322, USA
- Children’s Research Scholar, Children’s Healthcare of Atlanta, 2015 Uppergate Dr., Atlanta, GA 30322, USA
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13
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Mohammad PPS, Isarangura S, Eddins A, Parthasarathy AB. Comparison of functional activation responses from the auditory cortex derived using multi-distance frequency domain and continuous wave near-infrared spectroscopy. NEUROPHOTONICS 2021; 8:045004. [PMID: 34926716 PMCID: PMC8673635 DOI: 10.1117/1.nph.8.4.045004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 11/29/2021] [Indexed: 05/08/2023]
Abstract
Significance: Quantitative measurements of cerebral hemodynamic changes due to functional activation are widely accomplished with commercial continuous wave (CW-NIRS) instruments despite the availability of the more rigorous multi-distance frequency domain (FD-NIRS) approach. A direct comparison of the two approaches to functional near-infrared spectroscopy can help in the interpretation of optical data and guide implementations of diffuse optical instruments for measuring functional activation. Aim: We explore the differences between CW-NIRS and multi-distance FD-NIRS by comparing measurements of functional activation in the human auditory cortex. Approach: Functional activation of the human auditory cortex was measured using a commercial frequency domain near-infrared spectroscopy instrument for 70 dB sound pressure level broadband noise and pure tone (1000 Hz) stimuli. Changes in tissue oxygenation were calculated using the modified Beer-Lambert law (CW-NIRS approach) and the photon diffusion equation (FD-NIRS approach). Results: Changes in oxygenated hemoglobin measured with the multi-distance FD-NIRS approach were about twice as large as those measured with the CW-NIRS approach. A finite-element simulation of the functional activation problem was performed to demonstrate that tissue oxygenation changes measured with the CW-NIRS approach is more accurate than that with multi-distance FD-NIRS. Conclusions: Multi-distance FD-NIRS approaches tend to overestimate functional activation effects, in part due to partial volume effects.
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Affiliation(s)
| | - Sittiprapa Isarangura
- University of South Florida, Department of Communication Sciences and Disorders, Tampa, Florida, United States
| | - Ann Eddins
- University of South Florida, Department of Communication Sciences and Disorders, Tampa, Florida, United States
| | - Ashwin B. Parthasarathy
- University of South Florida, Department of Electrical Engineering, Tampa, Florida, United States
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14
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Blaney G, Curtsmith P, Sassaroli A, Fernandez C, Fantini S. Broadband absorption spectroscopy of heterogeneous biological tissue. APPLIED OPTICS 2021; 60:7552-7562. [PMID: 34613221 DOI: 10.1364/ao.431013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Absorption spectra (∼600 to 1064 nm) of six tissues in three healthy volunteers were measured by combining dual-slope continuous-wave broadband spectroscopy with self-calibrated frequency-domain measurements of scattering at two wavelengths (690 and 830 nm). The spectral fit with a linear combination of oxy- and deoxyhemoglobin, water, and lipids extinction spectra is improved by a wavelength-independent absorption background. The need to introduce this background is assigned to the inhomogeneous distribution of absorbers in tissue. By using a two-layer model, the relationship between recovered concentrations and their two-layer values was investigated, and the implications for non-invasive tissue spectroscopy are discussed.
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15
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Pham T, Blaney G, Sassaroli A, Fernandez C, Fantini S. Sensitivity of frequency-domain optical measurements to brain hemodynamics: simulations and human study of cerebral blood flow during hypercapnia. BIOMEDICAL OPTICS EXPRESS 2021; 12:766-789. [PMID: 33680541 PMCID: PMC7901322 DOI: 10.1364/boe.412766] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/04/2020] [Accepted: 12/16/2020] [Indexed: 05/20/2023]
Abstract
This study characterizes the sensitivity of noninvasive measurements of cerebral blood flow (CBF) by using frequency-domain near-infrared spectroscopy (FD-NIRS) and coherent hemodynamics spectroscopy (CHS). We considered six FD-NIRS methods: single-distance intensity and phase (SDI and SDϕ), single-slope intensity and phase (SSI and SSϕ), and dual-slope intensity and phase (DSI and DSϕ). Cerebrovascular reactivity (CVR) was obtained from the relative change in measured CBF during a step hypercapnic challenge. Greater measured values of CVR are assigned to a greater sensitivity to cerebral hemodynamics. In a first experiment with eight subjects, CVRSDϕ was greater than CVRSDI (p < 0.01), whereas CVRDSI and CVRDSϕ showed no significant difference (p > 0.5). In a second experiment with four subjects, a 5 mm scattering layer was added between the optical probe and the scalp tissue to increase the extracerebral layer thickness (L ec ), which caused CVRDSϕ to become significantly greater than CVRDSI (p < 0.05). CVRSS measurements yielded similar results as CVRDS measurements but with a greater variability, possibly resulting from instrumental artifacts in SS measurements. Theoretical simulations with two-layered media confirmed that, if the top (extracerebral) layer is more scattering than the bottom (brain) layer, the relative values of CVRDSI and CVRDSϕ depend on L ec . Specifically, the sensitivity to the brain is greater for DSI than DSϕ for a thin extracerebral layer (L ec < 13 mm), whereas it is greater for DSϕ than DSI for a thicker extracerebral layer.
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Affiliation(s)
- Thao Pham
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Giles Blaney
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Cristianne Fernandez
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Sergio Fantini
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
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16
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Yang L, Wabnitz H, Gladytz T, Sudakou A, Macdonald R, Grosenick D. Space-enhanced time-domain diffuse optics for determination of tissue optical properties in two-layered structures. BIOMEDICAL OPTICS EXPRESS 2020; 11:6570-6589. [PMID: 33282509 PMCID: PMC7687957 DOI: 10.1364/boe.402181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 05/05/2023]
Abstract
A novel methodology for solving the inverse problem of diffuse optics for two-layered structures is proposed to retrieve the absolute quantities of optical absorption and reduced scattering coefficients of the layers simultaneously. A liquid phantom with various optical absorption properties in the deep layer is prepared and experimentally investigated using the space-enhanced time-domain method. Monte-Carlo simulations are applied to analyze the different measurements in time domain, space domain, and by the new methodology. The deviations of retrieved values from nominal values of both layers' optical properties are simultaneously reduced to a very low extent compared to the single-domain methods. The reliability and uncertainty of the retrieval performance are also considerably improved by the new methodology. It is observed in time-domain analyses that for the deep layer the retrieval of absorption coefficient is almost not affected by the scattering properties and this kind of "deep scattering neutrality" is investigated and overcome as well.
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Affiliation(s)
- Lin Yang
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Thomas Gladytz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Aleh Sudakou
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Trojdena 4, 02-109 Warsaw, Poland
| | - Rainer Macdonald
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Dirk Grosenick
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
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17
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Milej D, Abdalmalak A, Rajaram A, St. Lawrence K. Direct assessment of extracerebral signal contamination on optical measurements of cerebral blood flow, oxygenation, and metabolism. NEUROPHOTONICS 2020; 7:045002. [PMID: 33062801 PMCID: PMC7540337 DOI: 10.1117/1.nph.7.4.045002] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 09/04/2020] [Indexed: 05/08/2023]
Abstract
Significance: Near-infrared spectroscopy (NIRS) combined with diffuse correlation spectroscopy (DCS) provides a noninvasive approach for monitoring cerebral blood flow (CBF), oxygenation, and oxygen metabolism. However, these methods are vulnerable to signal contamination from the scalp. Our work evaluated methods of reducing the impact of this contamination using time-resolved (TR) NIRS and multidistance (MD) DCS. Aim: The magnitude of scalp contamination was evaluated by measuring the flow, oxygenation, and metabolic responses to a global hemodynamic challenge. Contamination was assessed by collecting data with and without impeding scalp blood flow. Approach: Experiments involved healthy participants. A pneumatic tourniquet was used to cause scalp ischemia, as confirmed by contrast-enhanced NIRS, and a computerized gas system to generate a hypercapnic challenge. Results: Comparing responses acquired with and without the tourniquet demonstrated that the TR-NIRS technique could reduce scalp contributions in hemodynamic signals up to 4 times (r SD = 3 cm ) and 6 times (r SD = 4 cm ). Similarly, blood flow responses from the scalp and brain could be separated by analyzing MD DCS data with a multilayer model. Using these techniques, there was no change in metabolism during hypercapnia, as expected, despite large increases in CBF and oxygenation. Conclusion: NIRS/DCS can accurately monitor CBF and metabolism with the appropriate enhancement to depth sensitivity, highlighting the potential of these techniques for neuromonitoring.
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Affiliation(s)
- Daniel Milej
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Androu Abdalmalak
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Ajay Rajaram
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Keith St. Lawrence
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
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18
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Vera DA, Baez GR, García HA, Iriarte DI, Pomarico JA. A comparison between plausible models in layered turbid media with geometrical variations applying a Bayesian selection criterion. Biomed Phys Eng Express 2020; 6:055020. [PMID: 33444251 DOI: 10.1088/2057-1976/abae48] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
One possible application of Near Infrared techniques is to analyze human brain metabolic activity. Currently used models take into account the layered structure of the human head but, usually, they do not consider the non-planar surface of some of the boundaries, i.e. gray matter, which results in a much more complex structure, thus leading to more sophisticated models and longer calculation times. The main objective of this work is to determine if it is worth to replace a planar layered structure by a non-planar one. To this end we implement a Bayesian-based quantitative methodology for choosing between two competitive models describing light propagation in layered turbid media. Experiments of time-resolved diffuse reflectance measurements are performed in layered phantoms and complemented with numerical calculations. The resulting Distributions of Time of Flight of both models are compared using Bayesian model selection analysis. The non-planar interface was introduced in the simulations by a simple surface parametrization. Results suggest that, under certain conditions, a multilayer model with planar boundaries is good enough.
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Affiliation(s)
- Demián A Vera
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, UNCPBA-CICPBA - CONICET) Pinto 399, B7000GHG-Tandil, Buenos Aires, Argentina
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19
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Forti RM, Katsurayama M, Menko J, Valler L, Quiroga A, Falcão ALE, Li LM, Mesquita RC. Real-Time Non-invasive Assessment of Cerebral Hemodynamics With Diffuse Optical Spectroscopies in a Neuro Intensive Care Unit: An Observational Case Study. Front Med (Lausanne) 2020; 7:147. [PMID: 32411712 PMCID: PMC7198738 DOI: 10.3389/fmed.2020.00147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 04/06/2020] [Indexed: 12/30/2022] Open
Abstract
Prevention of secondary damage is an important goal in the treatment of severe neurological conditions, such as major head trauma or stroke. However, there is currently a lack of non-invasive methods for monitoring cerebral physiology. Diffuse optical methods have been proposed as an inexpensive, non-invasive bedside monitor capable of providing neurophysiology information in neurocritical patients. However, the reliability of the technique to provide accurate longitudinal measurement during the clinical evolution of a patient remains largely unaddressed. Here, we report on the translation of a hybrid diffuse optical system combining frequency domain diffuse optical spectroscopy (FD-DOS) and diffuse correlation spectroscopy (DCS) for real-time monitoring of cerebral physiology in a neuro intensive care unit (neuro-ICU). More specifically, we present a case study of a patient admitted with a high-grade aneurysmal subarachnoid hemorrhage, who was monitored throughout hospitalization. We show that the neurophysiological parameters measured by diffuse optics at the bedside are consistent with the clinical evolution of the patient at all the different stages following its brain lesion. These data provide support for clinical translation of DOS/DCS as a useful biomarker of neurophysiology in the neuro-ICU, particularly in locations where other clinical resources are limited.
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Affiliation(s)
- Rodrigo M Forti
- Institute of Physics, University of Campinas, Campinas, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology, Campinas, Brazil
| | - Marilise Katsurayama
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas, Brazil.,Clinical Hospital, University of Campinas, Campinas, Brazil
| | - Julien Menko
- Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Lenise Valler
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas, Brazil.,Clinical Hospital, University of Campinas, Campinas, Brazil
| | - Andres Quiroga
- Institute of Physics, University of Campinas, Campinas, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology, Campinas, Brazil
| | | | - Li M Li
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas, Brazil.,School of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Rickson C Mesquita
- Institute of Physics, University of Campinas, Campinas, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology, Campinas, Brazil
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20
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Fantini S, Sassaroli A. Frequency-Domain Techniques for Cerebral and Functional Near-Infrared Spectroscopy. Front Neurosci 2020; 14:300. [PMID: 32317921 PMCID: PMC7154496 DOI: 10.3389/fnins.2020.00300] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/16/2020] [Indexed: 12/31/2022] Open
Abstract
This article reviews the basic principles of frequency-domain near-infrared spectroscopy (FD-NIRS), which relies on intensity-modulated light sources and phase-sensitive optical detection, and its non-invasive applications to the brain. The simpler instrumentation and more straightforward data analysis of continuous-wave NIRS (CW-NIRS) accounts for the fact that almost all the current commercial instruments for cerebral NIRS have embraced the CW technique. However, FD-NIRS provides data with richer information content, which complements or exceeds the capabilities of CW-NIRS. One example is the ability of FD-NIRS to measure the absolute optical properties (absorption and reduced scattering coefficients) of tissue, and thus the absolute concentrations of oxyhemoglobin and deoxyhemoglobin in brain tissue. This article reviews the measured values of such optical properties and hemoglobin concentrations reported in the literature for animal models and for the human brain in newborns, infants, children, and adults. We also review the application of FD-NIRS to functional brain studies that focused on slower hemodynamic responses to brain activity (time scale of seconds) and faster optical signals that have been linked to neuronal activation (time scale of 100 ms). Another example of the power of FD-NIRS data is related to the different regions of sensitivity featured by intensity and phase data. We report recent developments that take advantage of this feature to maximize the sensitivity of non-invasive optical signals to brain tissue relative to more superficial extracerebral tissue (scalp, skull, etc.). We contend that this latter capability is a highly appealing quality of FD-NIRS, which complements absolute optical measurements and may result in significant advances in the field of non-invasive optical sensing of the brain.
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Affiliation(s)
- Sergio Fantini
- Department of Biomedical Engineering, Tufts University, Medford, MA, United States
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21
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Fantini S, Blaney G, Sassaroli A. Transformational change in the field of diffuse optics: From going bananas to going nuts. JOURNAL OF INNOVATIVE OPTICAL HEALTH SCIENCES 2020; 13:1930013. [PMID: 36340430 PMCID: PMC9632641 DOI: 10.1142/s1793545819300131] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The concept of region of sensitivity is central to the field of diffuse optics and is closely related to the Jacobian matrix used to solve the inverse problem in imaging. It is well-known that, in diffuse reflectance, the region of sensitivity associated with a given source-detector pair is shaped as a banana, and features maximal sensitivity to the portions of the sample that are closest to the source and the detector. We have recently introduced a dual-slope method based on a special arrangement of two sources and two detectors, which results in deeper and more localized regions of sensitivity, resembling the shapes of different kinds of nuts. Here, we report the regions of sensitivity associated with a variety of source-detector arrangements for dual-slope measurements of intensity and phase with frequency-domain spectroscopy (modulation frequency: 140 MHz) in a medium with absorption and reduced scattering coefficients of 0.1 cm-1 and 12 cm-1, respectively. The main result is that the depth of maximum sensitivity, considering only cases that use source-detector separations of 25 and 35 mm, progressively increases as we consider single-distance intensity (2.0 mm), dual-slope intensity (4.6 mm), single-distance phase (7.5 mm), and dual-slope phase (10.9 mm). These results indicate the importance of dual-slope measurements, and even more so of phase measurements, when it is desirable to selectively probe deeper portions of a sample with diffuse optics. This is certainly the case in non-invasive optical studies of brain, muscle, and breast tissue, which are located underneath superficial tissue at variable depths.
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Affiliation(s)
- Sergio Fantini
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
| | - Giles Blaney
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
| | - Angelo Sassaroli
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
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22
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Afshari A, Ghassemi P, Lin J, Halprin M, Wang J, Mendoza G, Weininger S, Pfefer TJ. Cerebral oximetry performance testing with a 3D-printed vascular array phantom. BIOMEDICAL OPTICS EXPRESS 2019; 10:3731-3746. [PMID: 31452971 PMCID: PMC6701524 DOI: 10.1364/boe.10.003731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 05/13/2023]
Abstract
Cerebral oximetry based on near-infrared spectroscopy represents a unique noninvasive tool for real-time surgical monitoring, yet studies have shown a significant discrepancy in accuracy among commercial systems. Towards the establishment of a standardized method for performance testing, we have studied a solid phantom approach - based on a 3D-printed cerebrovascular module (CVM) incorporating an array of 148 cylindrical channels - that has several advantages over liquid phantoms. Development and characterization of a CVM prototype are described, including high-resolution imaging and spectrophotometry measurements. The CVM was filled with whole bovine blood tuned over an oxygen saturation range of 30-90% and molded-silicone layers simulating extracerebral tissues were used to evaluate penetration depth. Saturation measurement accuracy was assessed in two commercially-available clinical cerebral oximeters. For one oximeter, both neonatal and pediatric sensors showed a high degree of precision, whereas accuracy was strongly dependent on saturation level and extracerebral geometry. The second oximeter showed worse precision, yet greater robustness to variations in extracerebral layers. These results indicate that 3D-printed channel array phantoms represent a promising new approach for standardized testing of clinical oximeters.
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23
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Hyper-spectral Recovery of Cerebral and Extra-Cerebral Tissue Properties Using Continuous Wave Near-Infrared Spectroscopic Data. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9142836] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Near-infrared spectroscopy (NIRS) is widely used as a non-invasive method to monitor the hemodynamics of biological tissue. A common approach of NIRS relies on continuous wave (CW) methodology, i.e. utilizing intensity-only measurements, and, in general, assumes homogeneity in the optical properties of the biological tissue. However, in monitoring cerebral hemodynamics within humans, this assumption is not valid due to complex layered structure of the head. The NIRS signal that contains information about cerebral blood hemoglobin levels is also contaminated with extra-cerebral tissue hemodynamics, and any recovery method based on such a priori homogenous approximation would lead to erroneous results. In this work, utilization of hyper-spectral intensity only measurements (i.e., CW) at multiple distances are presented and are shown to recover two-layered tissue properties along with the thickness of top layer, using an analytical solution for a two-layered semi-infinite geometry. It is demonstrated that the recovery of tissue oxygenation index (TOI) of both layers can be achieved with an error of 4.4%, with the recovered tissue thickness of 4% error. When the data is measured on a complex tissue such as the human head, it is shown that the semi-infinite recovery model can lead to uncertain results, whereas, when using an appropriate model accounting for the tissue-boundary structure, the tissue oxygenation levels are recovered with an error of 4.2%, and the extra-cerebral tissue thickness with an error of 11.8%. The algorithm is finally used together with human subject data, demonstrating robustness in application and repeatability in the recovered parameters that adhere well to expected published parameters.
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Forti RM, Favilla CG, Cochran JM, Baker WB, Detre JA, Kasner SE, Mullen MT, Messé SR, Kofke WA, Balu R, Kung D, Pukenas BA, Sedora-Roman NI, Hurst RW, Choudhri OA, Mesquita RC, Yodh AG. Transcranial Optical Monitoring of Cerebral Hemodynamics in Acute Stroke Patients during Mechanical Thrombectomy. J Stroke Cerebrovasc Dis 2019; 28:1483-1494. [PMID: 30975462 PMCID: PMC6686873 DOI: 10.1016/j.jstrokecerebrovasdis.2019.03.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/28/2019] [Accepted: 03/06/2019] [Indexed: 01/01/2023] Open
Abstract
INTRODUCTION Mechanical thrombectomy is revolutionizing treatment of acute stroke due to large vessel occlusion (LVO). Unfortunately, use of the modified Thrombolysis in Cerebral Infarction score (mTICI) to characterize recanalization of the cerebral vasculature does not address microvascular perfusion of the distal parenchyma, nor provide more than a vascular "snapshot." Thus, little is known about tissue-level hemodynamic consequences of LVO recanalization. Diffuse correlation spectroscopy (DCS) and diffuse optical spectroscopy (DOS) are promising methods for continuous, noninvasive, contrast-free transcranial monitoring of cerebral microvasculature. METHODS Here, we use a combined DCS/DOS system to monitor frontal lobe hemodynamic changes during endovascular treatment of 2 patients with ischemic stroke due to internal carotid artery (ICA) occlusions. RESULTS AND DISCUSSION The monitoring instrument identified a recanalization-induced increase in ipsilateral cerebral blood flow (CBF) with little or no concurrent change in contralateral CBF and extracerebral blood flow. The results suggest that diffuse optical monitoring is sensitive to intracerebral hemodynamics in patients with ICA occlusion and can measure microvascular responses to mechanical thrombectomy.
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Affiliation(s)
- Rodrigo M Forti
- Institute of Physics, University of Campinas, Campinas, SP, Brazil; Brazilian Institute of Neuroscience and Neurotechnology, Campinas, SP, Brazil; Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania.
| | | | - Jeffrey M Cochran
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Wesley B Baker
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - John A Detre
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Scott E Kasner
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael T Mullen
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Steven R Messé
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - W Andrew Kofke
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ramani Balu
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David Kung
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Bryan A Pukenas
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Neda I Sedora-Roman
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert W Hurst
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Omar A Choudhri
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rickson C Mesquita
- Institute of Physics, University of Campinas, Campinas, SP, Brazil; Brazilian Institute of Neuroscience and Neurotechnology, Campinas, SP, Brazil
| | - Arjun G Yodh
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania
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Mahmoodkalayeh S, Ansari MA, Tuchin VV. Head model based on the shape of the subject's head for optical brain imaging. BIOMEDICAL OPTICS EXPRESS 2019; 10:2795-2808. [PMID: 31259052 PMCID: PMC6583357 DOI: 10.1364/boe.10.002795] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/24/2019] [Accepted: 05/09/2019] [Indexed: 05/05/2023]
Abstract
Optical imaging methods such as near-infrared spectroscopy and diffuse optical tomography rely on models to solve the inverse problem. Imaging an adult human head also requires a head model. Using a model, which makes describing the structure of the head better, leads to acquiring a more accurate absorption map. Here, by combining the key features of layered slab models and head atlases, we introduce a new two-layered head model that is based on the surface geometry of the subject's head with variable thickness of the superficial layer. Using the Monte Carlo approach, we assess the performance of our model for fitting the optical properties from simulated time-resolved data of the adult head in a null distance source-detector configuration. Using our model, we observed improved results at 70 percent of the locations on the head and an overall 20 percent reduction in relative error compared to layered slab model.
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Affiliation(s)
- Sadreddin Mahmoodkalayeh
- Department of Physics, Shahid Beheshti University, Velenjak, Tehran, Iran
- Laser and Plasma Research Institute, Shahid Beheshti University, 1983969411, Tehran, Iran
| | - Mohammad Ali Ansari
- Laser and Plasma Research Institute, Shahid Beheshti University, 1983969411, Tehran, Iran
| | - Valery V. Tuchin
- Research-Educational Institute of Optics and Biophotonics, Saratov State University, Saratov, Russia
- Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
- Laboratory of Laser Diagnostics of Technical and Living Systems, Institute of Precision Mechanics and Control of the Russian Academy of Sciences, Saratov, Russia
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26
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Pham T, Tgavalekos K, Sassaroli A, Blaney G, Fantini S. Quantitative measurements of cerebral blood flow with near-infrared spectroscopy. BIOMEDICAL OPTICS EXPRESS 2019; 10:2117-2134. [PMID: 31061774 PMCID: PMC6484993 DOI: 10.1364/boe.10.002117] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/07/2019] [Accepted: 03/20/2019] [Indexed: 05/29/2023]
Abstract
We propose a new near-infrared spectroscopy (NIRS) method for quantitative measurements of cerebral blood flow (CBF). Because this method uses concepts of coherent hemodynamics spectroscopy (CHS), we identify this new method with the acronym NIRS-CHS. We tested this method on the prefrontal cortex of six healthy human subjects during mean arterial pressure (MAP) transients induced by the rapid deflation of pneumatic thigh cuffs. A comparison of CBF dynamics measured with NIRS-CHS and with diffuse correlation spectroscopy (DCS) showed a good agreement for characteristic times of the CBF transient. We also report absolute measurements of baseline CBF with NIRS-CHS (69 ± 6 ml/100g/min over the six subjects). NIRS-CHS can provide more accurate measurements of CBF with respect to previously reported NIRS surrogates of CBF.
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Affiliation(s)
- Thao Pham
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
| | - Kristen Tgavalekos
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
| | - Angelo Sassaroli
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
| | - Giles Blaney
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
| | - Sergio Fantini
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
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Selb J, Wu KC, Sutin J, Lin PY(I, Farzam P, Bechek S, Shenoy A, Patel AB, Boas DA, Franceschini MA, Rosenthal ES. Prolonged monitoring of cerebral blood flow and autoregulation with diffuse correlation spectroscopy in neurocritical care patients. NEUROPHOTONICS 2018; 5:045005. [PMID: 30450363 PMCID: PMC6233866 DOI: 10.1117/1.nph.5.4.045005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 09/24/2018] [Indexed: 05/13/2023]
Abstract
Monitoring of cerebral blood flow (CBF) and autoregulation are essential components of neurocritical care, but continuous noninvasive methods for CBF monitoring are lacking. Diffuse correlation spectroscopy (DCS) is a noninvasive diffuse optical modality that measures a CBF index ( CBF i ) in the cortex microvasculature by monitoring the rapid fluctuations of near-infrared light diffusing through moving red blood cells. We tested the feasibility of monitoring CBF i with DCS in at-risk patients in the Neurosciences Intensive Care Unit. DCS data were acquired continuously for up to 20 h in six patients with aneurysmal subarachnoid hemorrhage, as permitted by clinical care. Mean arterial blood pressure was recorded synchronously, allowing us to derive autoregulation curves and to compute an autoregulation index. The autoregulation curves suggest disrupted cerebral autoregulation in most patients, with the severity of disruption and the limits of preserved autoregulation varying between subjects. Our findings suggest the potential of the DCS modality for noninvasive, long-term monitoring of cerebral perfusion, and autoregulation.
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Affiliation(s)
- Juliette Selb
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Kuan-Cheng Wu
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Jason Sutin
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Pei-Yi (Ivy) Lin
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Parisa Farzam
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Sophia Bechek
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Apeksha Shenoy
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Aman B. Patel
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - David A. Boas
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Maria Angela Franceschini
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
- Address all correspondence to: Maria Angela Franceschini, E-mail:
| | - Eric S. Rosenthal
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
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García H, Baez G, Pomarico J. Simultaneous retrieval of optical and geometrical parameters of multilayered turbid media via state-estimation algorithms. BIOMEDICAL OPTICS EXPRESS 2018; 9:3953-3973. [PMID: 30338167 PMCID: PMC6191609 DOI: 10.1364/boe.9.003953] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 06/25/2018] [Accepted: 07/12/2018] [Indexed: 05/29/2023]
Abstract
In the present paper we propose an implementation of the Kalman filter algorithm, which allows simultaneous recovery of the absorption coefficient, the reduced scattering coefficient and the thicknesses of multi-layered turbid media, with the deepest layer taken as semi-infinite. The approach is validated by both Monte Carlo simulations and experiments, showing good results in structures made up of four layers. As it is a Bayesian algorithm, prior knowledge can be included to improve the accuracy of the retrieved unknowns. One of the most promising applications of this approach is the capability of real-time monitoring of living organs by near infrared spectroscopy. In particular, determination of blood perfusion in the adult head is one of the desired goals, allowing continuous control of stroke patients. This demands accurate measurement of the optical properties, especially absorption, of the head layers, from scalp to the cortex.
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Fredriksson I, Saager RB, Durkin AJ, Strömberg T. Evaluation of a pointwise microcirculation assessment method using liquid and multilayered tissue simulating phantoms. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-9. [PMID: 29139245 PMCID: PMC5872620 DOI: 10.1117/1.jbo.22.11.115004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/26/2017] [Indexed: 05/03/2023]
Abstract
A fiber-optic probe-based instrument, designed for assessment of parameters related to microcirculation, red blood cell tissue fraction (fRBC), oxygen saturation (SO2), and speed resolved perfusion, has been evaluated using state-of-the-art tissue phantoms. The probe integrates diffuse reflectance spectroscopy (DRS) at two source-detector separations and laser Doppler flowmetry, using an inverse Monte Carlo method for identifying the parameters of a multilayered tissue model. Here, we characterize the accuracy of the DRS aspect of the instrument using (1) liquid blood phantoms containing yeast and (2) epidermis-dermis mimicking solid-layered phantoms fabricated from polydimethylsiloxane, titanium oxide, hemoglobin, and coffee. The root-mean-square (RMS) deviations for fRBC for the two liquid phantoms were 11% and 5.3%, respectively, and 11% for the solid phantoms with highest hemoglobin signatures. The RMS deviation for SO2 was 5.2% and 2.9%, respectively, for the liquid phantoms, and 2.9% for the solid phantoms. RMS deviation for the reduced scattering coefficient (μs'), for the solid phantoms was 15% (475 to 850 nm). For the liquid phantoms, the RMS deviation in average vessel diameter (D) was 1 μm. In conclusion, the skin microcirculation parameters fRBC and SO2, as well as, μs' and D are estimated with reasonable accuracy.
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Affiliation(s)
- Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Stockholm, Sweden
- Address all correspondence to: Ingemar Fredriksson, E-mail:
| | - Rolf B. Saager
- University of California, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Anthony J. Durkin
- University of California, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
- University of California, Department of Biomedical Engineering, Irvine, California, United States
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- University of California, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
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Benni PB, MacLeod D, Ikeda K, Lin HM. A validation method for near-infrared spectroscopy based tissue oximeters for cerebral and somatic tissue oxygen saturation measurements. J Clin Monit Comput 2017; 32:269-284. [PMID: 28374103 PMCID: PMC5838152 DOI: 10.1007/s10877-017-0015-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/23/2017] [Indexed: 12/19/2022]
Abstract
We describe the validation methodology for the NIRS based FORE-SIGHT ELITE® (CAS Medical Systems, Inc., Branford, CT, USA) tissue oximeter for cerebral and somatic tissue oxygen saturation (StO2) measurements for adult subjects submitted to the United States Food and Drug Administration (FDA) to obtain clearance for clinical use. This validation methodology evolved from a history of NIRS validations in the literature and FDA recommended use of Deming regression and bootstrapping statistical validation methods. For cerebral validation, forehead cerebral StO2 measurements were compared to a weighted 70:30 reference (REF CXB) of co-oximeter internal jugular venous and arterial blood saturation of healthy adult subjects during a controlled hypoxia sequence, with a sensor placed on the forehead. For somatic validation, somatic StO2 measurements were compared to a weighted 70:30 reference (REF CXS) of co-oximetry central venous and arterial saturation values following a similar protocol, with sensors place on the flank, quadriceps muscle, and calf muscle. With informed consent, 25 subjects successfully completed the cerebral validation study. The bias and precision (1 SD) of cerebral StO2 compared to REF CXB was −0.14 ± 3.07%. With informed consent, 24 subjects successfully completed the somatic validation study. The bias and precision of somatic StO2 compared to REF CXS was 0.04 ± 4.22% from the average of flank, quadriceps, and calf StO2 measurements to best represent the global whole body REF CXS. The NIRS validation methods presented potentially provide a reliable means to test NIRS monitors and qualify them for clinical use.
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Affiliation(s)
- Paul B Benni
- CAS Medical Systems (CASMED), Inc., Branford, CT, USA.
| | - David MacLeod
- Human Pharmacology & Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Keita Ikeda
- Human Pharmacology & Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA.,Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA
| | - Hung-Mo Lin
- Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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31
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Auger H, Bherer L, Boucher É, Hoge R, Lesage F, Dehaes M. Quantification of extra-cerebral and cerebral hemoglobin concentrations during physical exercise using time-domain near infrared spectroscopy. BIOMEDICAL OPTICS EXPRESS 2016; 7:3826-3842. [PMID: 27867696 PMCID: PMC5102543 DOI: 10.1364/boe.7.003826] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/23/2016] [Accepted: 08/28/2016] [Indexed: 05/10/2023]
Abstract
Fitness is known to have beneficial effects on brain anatomy and function. However, the understanding of mechanisms underlying immediate and long-term neurophysiological changes due to exercise is currently incomplete due to the lack of tools to investigate brain function during physical activity. In this study, we used time-domain near infrared spectroscopy (TD-NIRS) to quantify and discriminate extra-cerebral and cerebral hemoglobin concentrations and oxygen saturation (SO2) in young adults at rest and during incremental intensity exercise. In extra-cerebral tissue, an increase in deoxy-hemoglobin (HbR) and a decrease in SO2 were observed while only cerebral HbR increased at high intensity exercise. Results in extra-cerebral tissue are consistent with thermoregulatory mechanisms to dissipate excess heat through skin blood flow, while cerebral changes are in agreement with cerebral blood flow (CBF) redistribution mechanisms to meet oxygen demand in activated regions during exercise. No significant difference was observed in oxy- (HbO2) and total hemoglobin (HbT). In addition HbO2, HbR and HbT increased with subject's peak power output (equivalent to the maximum oxygen volume consumption; VO2 peak) supporting previous observations of increased total mass of red blood cells in trained individuals. Our results also revealed known gender differences with higher hemoglobin in men. Our approach in quantifying both extra-cerebral and cerebral absolute hemoglobin during exercise may help to better interpret past and future continuous-wave NIRS studies that are prone to extra-cerebral contamination and allow a better understanding of acute cerebral changes due to physical exercise.
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Affiliation(s)
- Héloïse Auger
- Institute of Biomedical Engineering, Université de Montréal, Montréal, QC,
Canada
- Centre Hospitalier Universitaire Sainte-Justine, Montréal, QC,
Canada
| | - Louis Bherer
- Institut Universitaire de Gériatrie de Montréal, Montréal, QC,
Canada
- PERFORM Centre, Concordia University, Montréal, QC,
Canada
| | - Étienne Boucher
- Centre Hospitalier Universitaire Sainte-Justine, Montréal, QC,
Canada
| | - Richard Hoge
- Institut Universitaire de Gériatrie de Montréal, Montréal, QC,
Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC,
Canada
| | - Frédéric Lesage
- Institute of Biomedical Engineering, Université de Montréal, Montréal, QC,
Canada
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC,
Canada
| | - Mathieu Dehaes
- Institute of Biomedical Engineering, Université de Montréal, Montréal, QC,
Canada
- Centre Hospitalier Universitaire Sainte-Justine, Montréal, QC,
Canada
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, QC,
Canada
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Verdecchia K, Diop M, Lee A, Morrison LB, Lee TY, St. Lawrence K. Assessment of a multi-layered diffuse correlation spectroscopy method for monitoring cerebral blood flow in adults. BIOMEDICAL OPTICS EXPRESS 2016; 7:3659-3674. [PMID: 27699127 PMCID: PMC5030039 DOI: 10.1364/boe.7.003659] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/22/2016] [Accepted: 07/26/2016] [Indexed: 05/21/2023]
Abstract
Diffuse correlation spectroscopy (DCS) is a promising technique for brain monitoring as it can provide a continuous signal that is directly related to cerebral blood flow (CBF); however, signal contamination from extracerebral tissue can cause flow underestimations. The goal of this study was to investigate whether a multi-layered (ML) model that accounts for light propagation through the different tissue layers could successfully separate scalp and brain flow when applied to DCS data acquired at multiple source-detector distances. The method was first validated with phantom experiments. Next, experiments were conducted in a pig model of the adult head with a mean extracerebral tissue thickness of 9.8 ± 0.4 mm. Reductions in CBF were measured by ML DCS and computed tomography perfusion for validation; excellent agreement was observed by a mean difference of 1.2 ± 4.6% (CI95%: -31.1 and 28.6) between the two modalities, which was not significantly different.
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Affiliation(s)
- Kyle Verdecchia
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Mamadou Diop
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Albert Lee
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Laura B. Morrison
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Ting-Yim Lee
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario N6G 2V4, Canada
| | - Keith St. Lawrence
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
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Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study. PLoS One 2015; 10:e0131951. [PMID: 26158464 PMCID: PMC4497661 DOI: 10.1371/journal.pone.0131951] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 06/08/2015] [Indexed: 11/29/2022] Open
Abstract
Neuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions.
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Baker WB, Parthasarathy AB, Ko TS, Busch DR, Abramson K, Tzeng SY, Mesquita RC, Durduran T, Greenberg JH, Kung DK, Yodh AG. Pressure modulation algorithm to separate cerebral hemodynamic signals from extracerebral artifacts. NEUROPHOTONICS 2015; 2:035004. [PMID: 26301255 PMCID: PMC4524732 DOI: 10.1117/1.nph.2.3.035004] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 07/01/2015] [Indexed: 05/18/2023]
Abstract
We introduce and validate a pressure measurement paradigm that reduces extracerebral contamination from superficial tissues in optical monitoring of cerebral blood flow with diffuse correlation spectroscopy (DCS). The scheme determines subject-specific contributions of extracerebral and cerebral tissues to the DCS signal by utilizing probe pressure modulation to induce variations in extracerebral blood flow. For analysis, the head is modeled as a two-layer medium and is probed with long and short source-detector separations. Then a combination of pressure modulation and a modified Beer-Lambert law for flow enables experimenters to linearly relate differential DCS signals to cerebral and extracerebral blood flow variation without a priori anatomical information. We demonstrate the algorithm's ability to isolate cerebral blood flow during a finger-tapping task and during graded scalp ischemia in healthy adults. Finally, we adapt the pressure modulation algorithm to ameliorate extracerebral contamination in monitoring of cerebral blood oxygenation and blood volume by near-infrared spectroscopy.
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Affiliation(s)
- Wesley B. Baker
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
- Address all correspondence to: Wesley B. Baker, E-mail:
| | - Ashwin B. Parthasarathy
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Tiffany S. Ko
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - David R. Busch
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
- Children’s Hospital of Philadelphia, Division of Neurology, 3401 Civic Center Boulevard, Philadelphia, Pennsylvania 19104, United States
| | - Kenneth Abramson
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Shih-Yu Tzeng
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
- National Cheng Kung University, Department of Photonics, No. 1, University Road, Tainan City 701, Taiwan
| | - Rickson C. Mesquita
- University of Campinas, Institute of Physics, 777 R. Sergio Buarque de Holanda, Campinas 13083-859, Brazil
| | - Turgut Durduran
- ICFO-Institut de Ciències Fotòniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, Castelldefels (Barcelona) 08860, Spain
| | - Joel H. Greenberg
- University of Pennsylvania, Department of Neurology, 3450 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - David K. Kung
- Hospital of the University of Pennsylvania, Department of Neurosurgery, 3400 Spruce Street, Philadelphia, Pennsylvania 19104, United States
| | - Arjun G. Yodh
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
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35
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Farina A, Torricelli A, Bargigia I, Spinelli L, Cubeddu R, Foschum F, Jäger M, Simon E, Fugger O, Kienle A, Martelli F, Di Ninni P, Zaccanti G, Milej D, Sawosz P, Kacprzak M, Liebert A, Pifferi A. In-vivo multilaboratory investigation of the optical properties of the human head. BIOMEDICAL OPTICS EXPRESS 2015. [PMID: 26203385 PMCID: PMC4505713 DOI: 10.1364/boe.6.002609] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The in-vivo optical properties of the human head are investigated in the 600-1100 nm range on different subjects using continuous wave and time domain diffuse optical spectroscopy. The work was performed in collaboration with different research groups and the different techniques were applied to the same subject. Data analysis was carried out using homogeneous and layered models and final results were also confirmed by Monte Carlo simulations. The depth sensitivity of each technique was investigated and related to the probed region of the cerebral tissue. This work, based on different validated instruments, is a contribution to fill the existing gap between the present knowledge and the actual in-vivo values of the head optical properties.
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Affiliation(s)
- Andrea Farina
- Consiglio Nazionale delle Ricerche - Istituto di Fotonica e Nanotecnologie, Piazza L. da Vinci 32, I-20133 Milano,
Italy
| | - Alessandro Torricelli
- POLIMI, Politecnico di Milano, Dipartimento di Fisica, Piazza L. Da Vinci 32, I-20133 Milano,
Italy
| | - Ilaria Bargigia
- Center for Nano-Science and Technology @POLIMI, Istituto Italiano di Tecnologia, via G. Pascoli 70/3, 20133 Milano,
Italy
| | - Lorenzo Spinelli
- Consiglio Nazionale delle Ricerche - Istituto di Fotonica e Nanotecnologie, Piazza L. da Vinci 32, I-20133 Milano,
Italy
| | - Rinaldo Cubeddu
- POLIMI, Politecnico di Milano, Dipartimento di Fisica, Piazza L. Da Vinci 32, I-20133 Milano,
Italy
| | - Florian Foschum
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Marion Jäger
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Emanuel Simon
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Oliver Fugger
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Alwin Kienle
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Fabrizio Martelli
- UNIFI, Università degli Studi di Firenze - Dipartimento di Fisica e Astronomia, Via G. Sansone, N. 1, 50019 Sesto Fiorentino, Firenze,
Italy
| | - Paola Di Ninni
- UNIFI, Università degli Studi di Firenze - Dipartimento di Fisica e Astronomia, Via G. Sansone, N. 1, 50019 Sesto Fiorentino, Firenze,
Italy
| | - Giovanni Zaccanti
- UNIFI, Università degli Studi di Firenze - Dipartimento di Fisica e Astronomia, Via G. Sansone, N. 1, 50019 Sesto Fiorentino, Firenze,
Italy
| | - Daniel Milej
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Piotr Sawosz
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Michał Kacprzak
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Adam Liebert
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Antonio Pifferi
- Consiglio Nazionale delle Ricerche - Istituto di Fotonica e Nanotecnologie, Piazza L. da Vinci 32, I-20133 Milano,
Italy
- POLIMI, Politecnico di Milano, Dipartimento di Fisica, Piazza L. Da Vinci 32, I-20133 Milano,
Italy
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36
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Baker WB, Parthasarathy AB, Busch DR, Mesquita RC, Greenberg JH, Yodh AG. Modified Beer-Lambert law for blood flow. BIOMEDICAL OPTICS EXPRESS 2014; 5:4053-75. [PMID: 25426330 PMCID: PMC4242038 DOI: 10.1364/boe.5.004053] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 05/18/2023]
Abstract
We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues.
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Affiliation(s)
- Wesley B. Baker
- Dept. Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104,
USA
| | | | - David R. Busch
- Dept. Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104,
USA
- Div. of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104,
USA
| | - Rickson C. Mesquita
- Institute of Physics, University of Campinas, Campinas, SP 13083-859,
Brazil
| | - Joel H. Greenberg
- Dept. Neurology, University of Pennsylvania, Philadelphia, PA 19104,
USA
| | - A. G. Yodh
- Dept. Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104,
USA
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37
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Selb J, Boas DA, Chan ST, Evans KC, Buckley EM, Carp SA. Sensitivity of near-infrared spectroscopy and diffuse correlation spectroscopy to brain hemodynamics: simulations and experimental findings during hypercapnia. NEUROPHOTONICS 2014; 1:015005. [PMID: 25453036 PMCID: PMC4247161 DOI: 10.1117/1.nph.1.1.015005] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 06/12/2014] [Accepted: 06/25/2014] [Indexed: 05/18/2023]
Abstract
Near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) are two diffuse optical technologies for brain imaging that are sensitive to changes in hemoglobin concentrations and blood flow, respectively. Measurements for both modalities are acquired on the scalp, and therefore hemodynamic processes in the extracerebral vasculature confound the interpretation of cortical hemodynamic signals. The sensitivity of NIRS to the brain versus the extracerebral tissue and the contrast-to-noise ratio (CNR) of NIRS to cerebral hemodynamic responses have been well characterized, but the same has not been evaluated for DCS. This is important to assess in order to understand their relative capabilities in measuring cerebral physiological changes. We present Monte Carlo simulations on a head model that demonstrate that the relative brain-to-scalp sensitivity is about three times higher for DCS (0.3 at 3 cm) than for NIRS (0.1 at 3 cm). However, because DCS has higher levels of noise due to photon-counting detection, the CNR is similar for both modalities in response to a physiologically realistic simulation of brain activation. Even so, we also observed higher CNR of the hemodynamic response during graded hypercapnia in adult subjects with DCS than with NIRS.
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Affiliation(s)
- Juliette Selb
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Department of Radiology, Optics Division, 149 13th Street, Charlestown, Massachusetts 02129, United States
- Address all correspondence to: Juliette Selb, E-mail:
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Department of Radiology, Optics Division, 149 13th Street, Charlestown, Massachusetts 02129, United States
| | - Suk-Tak Chan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Department of Radiology, Optics Division, 149 13th Street, Charlestown, Massachusetts 02129, United States
| | - Karleyton C. Evans
- Massachusetts General Hospital, Harvard Medical School, Department of Psychiatry, 149 13th Street, Charlestown, Massachusetts 02129, United States
| | - Erin M. Buckley
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Department of Radiology, Optics Division, 149 13th Street, Charlestown, Massachusetts 02129, United States
| | - Stefan A. Carp
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Department of Radiology, Optics Division, 149 13th Street, Charlestown, Massachusetts 02129, United States
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38
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Selb J, Ogden TM, Dubb J, Fang Q, Boas DA. Comparison of a layered slab and an atlas head model for Monte Carlo fitting of time-domain near-infrared spectroscopy data of the adult head. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:16010. [PMID: 24407503 PMCID: PMC3886581 DOI: 10.1117/1.jbo.19.1.016010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/11/2013] [Accepted: 12/13/2013] [Indexed: 05/18/2023]
Abstract
Near-infrared spectroscopy (NIRS) estimations of the adult brain baseline optical properties based on a homogeneous model of the head are known to introduce significant contamination from extracerebral layers. More complex models have been proposed and occasionally applied to in vivo data, but their performances have never been characterized on realistic head structures. Here we implement a flexible fitting routine of time-domain NIRS data using graphics processing unit based Monte Carlo simulations. We compare the results for two different geometries: a two-layer slab with variable thickness of the first layer and a template atlas head registered to the subject's head surface. We characterize the performance of the Monte Carlo approaches for fitting the optical properties from simulated time-resolved data of the adult head. We show that both geometries provide better results than the commonly used homogeneous model, and we quantify the improvement in terms of accuracy, linearity, and cross-talk from extracerebral layers.
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Affiliation(s)
- Juliette Selb
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
- Address all correspondence to: Juliette Selb, E-mail:
| | - Tyler M. Ogden
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
| | - Jay Dubb
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
| | - Qianqian Fang
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
| | - David A. Boas
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
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39
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Basso Moro S, Cutini S, Ursini ML, Ferrari M, Quaresima V. Prefrontal cortex activation during story encoding/retrieval: a multi-channel functional near-infrared spectroscopy study. Front Hum Neurosci 2013; 7:925. [PMID: 24427131 PMCID: PMC3876278 DOI: 10.3389/fnhum.2013.00925] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/17/2013] [Indexed: 12/14/2022] Open
Abstract
Encoding, storage and retrieval constitute three fundamental stages in information processing and memory. They allow for the creation of new memory traces, the maintenance and the consolidation of these traces over time, and the access and recover of the stored information from short or long-term memory. Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures concentration changes of oxygenated-hemoglobin (O2Hb) and deoxygenated-hemoglobin (HHb) in cortical microcirculation blood vessels by means of the characteristic absorption spectra of hemoglobin in the near-infrared range. In the present study, we monitored, using a 16-channel fNIRS system, the hemodynamic response during the encoding and retrieval processes (EP and RP, respectively) over the prefrontal cortex (PFC) of 13 healthy subjects (27.2 ± 2.6 years) while were performing the “Logical Memory Test” (LMT) of the Wechsler Memory Scale. A LMT-related PFC activation was expected; specifically, it was hypothesized a neural dissociation between EP and RP. The results showed a heterogeneous O2Hb/HHb response over the mapped area during the EP and the RP, with a O2Hb progressive and prominent increment in ventrolateral PFC (VLPFC) since the beginning of the EP. During the RP a broader activation, including the VLPFC, the dorsolateral PFC and the frontopolar cortex, was observed. This could be explained by the different contributions of the PFC regions in the EP and the RP. Considering the fNIRS applicability for the hemodynamic monitoring during the LMT performance, this study has demonstrated that fNIRS could be utilized as a valuable clinical diagnostic tool, and that it has the potential to be adopted in patients with cognitive disorders or slight working memory deficits.
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Affiliation(s)
- Sara Basso Moro
- Department of Life, Health and Environmental Sciences, University of L'Aquila L'Aquila, Italy
| | - Simone Cutini
- Department of General Psychology, University of Padua Padova, Italy
| | - Maria Laura Ursini
- Department of Life, Health and Environmental Sciences, University of L'Aquila L'Aquila, Italy
| | - Marco Ferrari
- Department of Life, Health and Environmental Sciences, University of L'Aquila L'Aquila, Italy
| | - Valentina Quaresima
- Department of Life, Health and Environmental Sciences, University of L'Aquila L'Aquila, Italy
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40
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Prefrontal Cortex Activated Bilaterally by a Tilt Board Balance Task: A Functional Near-Infrared Spectroscopy Study in a Semi-Immersive Virtual Reality Environment. Brain Topogr 2013; 27:353-65. [DOI: 10.1007/s10548-013-0320-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 09/25/2013] [Indexed: 12/14/2022]
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