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Youssef D, Fekry O, Badr A, Afify A, Hamed E. A new perspective on quantitative assessment of photodynamic therapy mediated hydrogel nanocomposite in wound healing using objective biospeckle and morphological local-gradient. Comput Biol Med 2023; 163:107196. [PMID: 37356291 DOI: 10.1016/j.compbiomed.2023.107196] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 06/03/2023] [Accepted: 06/19/2023] [Indexed: 06/27/2023]
Abstract
Skin wounding is a serious public health issue, especially when considering factors that accelerate tissue recovery. Consequently, the use of photodynamic therapy (PDT) as an effective wound-healing treatment has attracted more scientific attention. Although assessing the wound healing rate is crucial for appropriate monitoring of the probability of wound healing and evaluating the treatment efficiency, the currently used techniques lack the ability to provide such information. Therefore, this study has two aims, first, it contributes to the development of a new image-guided biospeckle system for quantitative monitoring of skin wound healing rate. Second, it evaluates the potential of using a novel synthesized PDT-mediated polyethylene glycol fabric with methylene blue (PEG-MB) hydrogel nanocomposite in accelerating wound healing. The proposed imaging system initially acquires raw biospeckle images from the wound regions of adult healthy albino mice treated with the synthesized hydrogel nanocomposite. Each raw biospeckle image is then converted into maps of morphological local-gradient matrices implemented from the combination of dilation and erosion operations at different radii up to 25 pixels. Subsequently, their intensity histogram statistics are computed, taking central moments as the feature set. Final characterization is achieved via a linear combination of the biospeckle statistics maintaining as much variance as possible using principal component analysis (PCA). The results confirmed by cytokine concentration measurement and histological investigation demonstrate that the innovative biospeckle image-guided system is ideal for investigating wound healing and suggest the potential of the hydrogel nanocomposite as an active dressing.
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Affiliation(s)
- Doaa Youssef
- Department of Engineering Applications of Lasers, National Institute of Laser Enhanced Sciences, Cairo University, Egypt.
| | - Osama Fekry
- Department of Medical Applications of Lasers, National Institute of Laser Enhanced Sciences, Cairo University, Egypt
| | - Abeer Badr
- Department of Zoology, Faculty of Science, Cairo University, Egypt
| | - Ahmed Afify
- Department of Zoology, Faculty of Science, Cairo University, Egypt
| | - Eman Hamed
- Department of Zoology, Faculty of Science, Cairo University, Egypt
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2
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Erdmann S, Weissgerber F, Colin Koeniguer É, Orlik X. Dynamic speckle imaging of human skin vasculature with a high-speed camera. OPTICS EXPRESS 2022; 30:11923-11943. [PMID: 35473125 DOI: 10.1364/oe.452111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/26/2022] [Indexed: 06/14/2023]
Abstract
We demonstrate the ability of high-speed acquisition (up to 30 kHz) of dynamic speckle to provide images of the human vascularization at various scales. A comparative study involving the speckle contrast, the first term of the intensity autocorrelation function, and the zero-crossings of the field intensity is proposed, together with a proper preprocessing scheme based on image registration and filtering. Experimental results show the potential of the first term of the autocorrelation function to provide efficient model-free mapping of the microvascular activity (i.e. small-scale random motion associated with the presence of a vessel). With the help of this parameter, various scales of vascularization including large vessels in the wrist, microvessels in the ear and fingers, and thinner inflammatory structures are observed, which suggests the imaging abilities of this parameter are broad. The minimum acquisition time is shown to be of the order of 50 ms, demonstrating video imaging capabilities.
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3
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Guzman-Sepulveda JR, Batarseh M, Wu R, DeCampli WM, Dogariu A. Passive high-frequency microrheology of blood. SOFT MATTER 2022; 18:2452-2461. [PMID: 35279707 PMCID: PMC8941587 DOI: 10.1039/d1sm01726h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Indicative of various pathologies, blood properties are under intense scrutiny. The hemorheological characteristics are traditionally gauged by bulk, low-frequency indicators that average out critical information about the complex, multi-scale, and multi-component structure. In particular, one cannot discriminate between the erythrocytes contribution to global rheology and the impact of plasma. Nevertheless, in their fast stochastic movement, before they encounter each other, the erythrocytes probe the subtle viscoelasticity of their protein-rich environment. Thus, if these short time scales can be resolved experimentally, the plasma properties could be determined without having to separate the blood components; the blood is practically testing itself. This microrheological description of blood plasma provides a direct link between the composition of whole blood and its coagulability status. We present a parametric model for the viscoelasticity of plasma, which is probed by the erythrocytes over frequency ranges of kilohertz in a picoliter-sized volume. The model is validated both in vitro, using artificial hemo-systems where the composition is controlled, as well as on whole blood where continuous measurements provide real-time information. We also discuss the possibility of using this passive microrheology as an in vivo assay for clinically relevant situations where the blood clotting condition must be observed and managed continuously for diagnosis or during therapeutic procedures at different stages of hemostatic and thrombotic processes.
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Affiliation(s)
- Jose Rafael Guzman-Sepulveda
- CREOL, The College of Optics and Photonics, University of Central Florida, 4304 Scorpius, Orlando, Florida, 32816, USA.
| | - Mahed Batarseh
- CREOL, The College of Optics and Photonics, University of Central Florida, 4304 Scorpius, Orlando, Florida, 32816, USA.
| | - Ruitao Wu
- CREOL, The College of Optics and Photonics, University of Central Florida, 4304 Scorpius, Orlando, Florida, 32816, USA.
| | - William M DeCampli
- Pediatric Cardiothoracic Surgery, The Heart Center, Arnold Palmer Hospital for Children, Orlando, Florida, USA
- College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Aristide Dogariu
- CREOL, The College of Optics and Photonics, University of Central Florida, 4304 Scorpius, Orlando, Florida, 32816, USA.
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Hajjarian Z, Nadkarni SK. Technological perspectives on laser speckle micro-rheology for cancer mechanobiology research. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210119-PER. [PMID: 34549559 PMCID: PMC8455299 DOI: 10.1117/1.jbo.26.9.090601] [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: 04/12/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE The ability to measure the micro-mechanical properties of biological tissues and biomaterials is crucial for numerous fields of cancer research, including tumor mechanobiology, tumor-targeting drug delivery, and therapeutic development. AIM Our goal is to provide a renewed perspective on the mainstream techniques used for micro-mechanical evaluation of biological tissues and biomimetic scaffoldings. We specifically focus on portraying the outlook of laser speckle micro-rheology (LSM), a technology that quantifies the mechanical properties of biomaterials and tissues in a rapid, non-contact manner. APPROACH First, we briefly explain the motivation and significance of evaluating the tissue micro-mechanics in various fields of basic and translational cancer research and introduce the key concepts and quantitative metrics used to explain the mechanical properties of tissue. This is followed by reviewing the general active and passive themes of measuring micro-mechanics. Next, we focus on LSM and elaborate on the theoretical grounds and working principles of this technique. Then, the perspective for measuring the micro-mechanical properties via LSM is outlined. Finally, we draw an overview picture of LSM in cancer mechanobiology research. RESULTS With the continued emergence of new approaches for measuring the mechanical attributes of biological tissues, the field of micro-mechanical imaging is at its boom. As one of these competent innovations, LSM presents a tremendous potential for both technical maturation and prospective applications in cancer biomechanics and mechanobiology research. CONCLUSION By elaborating the current viewpoint of LSM, we expect to accelerate the expansion of this approach to new territories in both technological domains and applied fields. This renewed perspective on LSM may also serve as a road map for other micro-mechanical measurement concepts to be applied for answering mechanobiological questions.
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Affiliation(s)
- Zeinab Hajjarian
- Harvard Medical School, Massachusetts General Hospital, Wellman Center for Photomedicine, Boston, Massachusetts, United States
| | - Seemantini K. Nadkarni
- Harvard Medical School, Massachusetts General Hospital, Wellman Center for Photomedicine, Boston, Massachusetts, United States
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5
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Hajjarian Z, Toussaint JD, Guerrero JL, Nadkarni SK. In-vivo mechanical characterization of coronary atherosclerotic plaques in living swine using intravascular laser speckle imaging. BIOMEDICAL OPTICS EXPRESS 2021; 12:2064-2078. [PMID: 33996217 PMCID: PMC8086462 DOI: 10.1364/boe.418939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/07/2021] [Accepted: 02/09/2021] [Indexed: 05/13/2023]
Abstract
The ability to evaluate the viscoelastic properties of coronary arteries is crucial for identifying mechanically unstable atherosclerotic plaques. Here, we demonstrate for the first time in living swine, the capability of intravascular laser speckle imaging (ILSI) to measure an index of coronary plaque viscoelasticity, τ, using a human coronary to swine xenograft model. Cardiac motion effects are evaluated by comparing the EKG-non-gated τ ¯ N G , and EKG-gated τ ¯ G among different plaque types. Results show that both τ ¯ N G and τ ¯ G are significantly lower in necrotic-core plaques compared with stable lesions. Discrete-point pullback measurements demonstrate the capability of ILSI for rapid mechanical characterization of coronary segments under physiological conditions, in-vivo.
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Affiliation(s)
- Zeinab Hajjarian
- Wellman Center for Photomedicine, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
- Authors contributed equally to the manuscript
| | - Jimmy D. Toussaint
- Wellman Center for Photomedicine, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
- Authors contributed equally to the manuscript
| | - J. Luis Guerrero
- Surgical Cardiovascular Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Seemantini K. Nadkarni
- Wellman Center for Photomedicine, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
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6
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Farzam Rad V, Panahi M, Jamali R, Darudi A, Moradi AR. Non-invasive in situ monitoring of bone scaffold activity by speckle pattern analysis. BIOMEDICAL OPTICS EXPRESS 2020; 11:6324-6336. [PMID: 33282493 PMCID: PMC7687950 DOI: 10.1364/boe.401740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 06/01/2023]
Abstract
Scaffold-based bone tissue engineering aims to develop 3D scaffolds that mimic the extracellular matrix to regenerate bone defects and damages. In this paper, we provide a laser speckle analysis to characterize the highly porous scaffold. The experimental procedure includes in situ acquisition of speckle patterns of the bone scaffold at different times under preserved environmental conditions, and follow-up statistical post-processing toward examining its internal activity. The activity and overall viscoelastic properties of scaffolds are expressed via several statistical parameters, and the variations in the computed parameters are attributed to time-varying activity of the samples during their internal substructure migration.
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Affiliation(s)
- Vahideh Farzam Rad
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
| | - Majid Panahi
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan 45371-38791, Iran
| | - Ramin Jamali
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
| | - Ahmad Darudi
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan 45371-38791, Iran
| | - Ali-Reza Moradi
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran
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7
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El Cheikh A, Pellen F, Le Jeune B, Le Brun G, Abboud M. Single speckle image analysis for monitoring the hardening kinetics of glass ionomer cements. APPLIED OPTICS 2020; 59:8828-8833. [PMID: 33104567 DOI: 10.1364/ao.403027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
In this paper, we monitor the setting reaction of commercial glass ionomer cements using a laser speckle technique and adopting a spatial approach in the analysis of recorded speckle images. Experimental results showed that spatial contrast and speckle grain size increased as two studied cements underwent their setting reactions. After combining two geometrical configurations to measure the intensities of backscattered and transmitted light, we concluded that the increase in speckle grain size was caused by an increase in size of the scattering centers, since cement components aggregate and hence transition from a Rayleigh to a Mie scattering regime. Finally, two main phases were distinguished in the hardening process, as reported in the literature; however, the technique we propose has the advantage of easily identifying these two phases. The analysis of a single speckle image offers multiple advantages over the temporal analysis of a series of speckle images, in particular due to the low number of images recorded and a far shorter image processing time.
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8
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Hajjarian Z, Nadkarni SK. Tutorial on laser speckle rheology: technology, applications, and opportunities. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-19. [PMID: 32358928 PMCID: PMC7195443 DOI: 10.1117/1.jbo.25.5.050801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/10/2020] [Indexed: 05/27/2023]
Abstract
SIGNIFICANCE The onset of several diseases is frequently marked with anomalous mechanical alteration of the affected tissue at the intersection of cells and their microenvironment. Therefore, mapping the micromechanical attributes of the tissues could enhance our understanding of the etiology of human disease, improve the diagnosis, and help stratify therapies that target these mechanical aberrations. AIM We review the tremendous opportunities offered through using optics for imaging the micromechanical properties, at length scales inaccessible to other modalities, in both basic research and clinical medicine. We specifically focus on laser speckle rheology (LSR), a technology that quantifies the mechanical properties of tissues in a rapid, noncontact manner. APPROACH In LSR, the shear viscoelastic modulus is measured from the time-variant speckle intensity fluctuations reflected off the tissue. The LSR technology is engineered and configured into several embodiments, including bench-top optical systems, endoscopes for minimally invasive procedures, portable point-of-care devices, and microscopes. RESULTS These technological nuances have primed the LSR for widespread applications in diagnosis and therapeutic monitoring, as demonstrated here, in cardiovascular disease, coagulation disorders, and tumor malignancies. CONCLUSION The fast-paced technological advancements, elaborated here, position the LSR as a competent candidate for many more exciting opportunities in basic research and medicine.
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Affiliation(s)
- Zeinab Hajjarian
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
| | - Seemantini K. Nadkarni
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
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9
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Mohammadi Aria M, Erten A, Yalcin O. Technology Advancements in Blood Coagulation Measurements for Point-of-Care Diagnostic Testing. Front Bioeng Biotechnol 2019; 7:395. [PMID: 31921804 PMCID: PMC6917661 DOI: 10.3389/fbioe.2019.00395] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/21/2019] [Indexed: 12/24/2022] Open
Abstract
In recent years, blood coagulation monitoring has become crucial to diagnosing causes of hemorrhages, developing anticoagulant drugs, assessing bleeding risk in extensive surgery procedures and dialysis, and investigating the efficacy of hemostatic therapies. In this regard, advanced technologies such as microfluidics, fluorescent microscopy, electrochemical sensing, photoacoustic detection, and micro/nano electromechanical systems (MEMS/NEMS) have been employed to develop highly accurate, robust, and cost-effective point of care (POC) devices. These devices measure electrochemical, optical, and mechanical parameters of clotting blood. Which can be correlated to light transmission/scattering, electrical impedance, and viscoelastic properties. In this regard, this paper discusses the working principles of blood coagulation monitoring, physical and sensing parameters in different technologies. In addition, we discussed the recent progress in developing nanomaterials for blood coagulation detection and treatments which opens up new area of controlling and monitoring of coagulation at the same time in the future. Moreover, commercial products, future trends/challenges in blood coagulation monitoring including novel anticoagulant therapies, multiplexed sensing platforms, and the application of artificial intelligence in diagnosis and monitoring have been included.
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Affiliation(s)
| | - Ahmet Erten
- Department of Electronics and Communication Engineering, Istanbul Technical University, Istanbul, Turkey
| | - Ozlem Yalcin
- Graduate School of Biomedical Sciences and Engineering, Koc University, Sariyer, Turkey
- Department of Physiology, Koc University School of Medicine, Koc University, Sariyer, Turkey
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10
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Rizwan M, Ganjkhani Y, Farzam Rad V, Bazzar M, Yar M, Yahya R, Moradi A. Surface characterizations of membranes and electrospun chitosan derivatives by optical speckle analysis. SURF INTERFACE ANAL 2019. [DOI: 10.1002/sia.6731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Muhammad Rizwan
- Department of ChemistryUniversiti Malaya Kuala Lumpur Malaysia
- Department of ChemistryThe University of Lahore Lahore Pakistan
| | - Yasaman Ganjkhani
- Department of PhysicsInstitute for Advanced Studies in Basic Sciences (IASBS) Zanjan Iran
| | - Vahideh Farzam Rad
- Department of PhysicsInstitute for Advanced Studies in Basic Sciences (IASBS) Zanjan Iran
| | - Maasoomeh Bazzar
- School of ChemistryUniversity of East Anglia, Norwich Research Park Norwich UK
| | - Muhammad Yar
- Interdisciplinary Research Center in Biomedical MaterialsCOMSATS University Lahore Pakistan
| | - Rosiyah Yahya
- Department of ChemistryUniversiti Malaya Kuala Lumpur Malaysia
| | - Ali‐Reza Moradi
- Department of PhysicsInstitute for Advanced Studies in Basic Sciences (IASBS) Zanjan Iran
- School of Nano ScienceInstitute for Research in Fundamental Sciences (IPM) Tehran Iran
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11
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Larin KV, Scarcelli G, Yakovlev VV. Optical elastography and tissue biomechanics. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-9. [PMID: 31758675 PMCID: PMC6873628 DOI: 10.1117/1.jbo.24.11.110901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 10/31/2019] [Indexed: 05/18/2023]
Abstract
Mechanical forces play an important role in the behavior and development of biological systems and disease at all spatial scales, from cells and their constituents to tissues and organs. Such forces have a profound influence on the health, structural integrity, and normal function of cells and organs. Accurate knowledge of cell and tissue biomechanical properties is essential to map the distribution of forces and mechanical cues in biological systems. Cell and tissue biomechanical properties are also known to be important on their own as indicators of health or diseases state. Hence, optical elastography and biomechanics methods can aid in the understanding and clinical diagnosis of a wide variety of diseases. We provide a brief overview and highlight of the Optical Elastography and Tissue Biomechanics VI conference, which took place in San Francisco, February 2 and 3, 2019, as a part of Photonics West symposium.
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Affiliation(s)
- Kirill V. Larin
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Giuliano Scarcelli
- University of Maryland, Department of Biomedical Engineering, College Park, Maryland, United States
| | - Vladislav V. Yakovlev
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
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12
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van der Kooij HM, Semerdzhiev SA, Buijs J, Broer DJ, Liu D, Sprakel J. Morphing of liquid crystal surfaces by emergent collectivity. Nat Commun 2019; 10:3501. [PMID: 31383859 PMCID: PMC6683186 DOI: 10.1038/s41467-019-11501-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/08/2019] [Indexed: 11/22/2022] Open
Abstract
Liquid crystal surfaces can undergo topographical morphing in response to external cues. These shape-shifting coatings promise a revolution in various applications, from haptic feedback in soft robotics or displays to self-cleaning solar panels. The changes in surface topography can be controlled by tailoring the molecular architecture and mechanics of the liquid crystal network. However, the nanoscopic mechanisms that drive morphological transitions remain unclear. Here, we introduce a frequency-resolved nanostrain imaging method to elucidate the emergent dynamics underlying field-induced shape-shifting. We show how surface morphing occurs in three distinct stages: (i) the molecular dipoles oscillate with the alternating field (10-100 ms), (ii) this leads to collective plasticization of the glassy network (~1 s), (iii) culminating in actuation of the topography (10-100 s). The first stage appears universal and governed by dielectric coupling. By contrast, yielding and deformation rely on a delicate balance between liquid crystal order, field properties and network viscoelasticity.
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Affiliation(s)
- Hanne M van der Kooij
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708, WE, Wageningen, The Netherlands
- Dutch Polymer Institute (DPI), P.O. Box 902, 5600, AX, Eindhoven, The Netherlands
| | - Slav A Semerdzhiev
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708, WE, Wageningen, The Netherlands
- Dutch Polymer Institute (DPI), P.O. Box 902, 5600, AX, Eindhoven, The Netherlands
| | - Jesse Buijs
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708, WE, Wageningen, The Netherlands
| | - Dirk J Broer
- Stimuli-responsive Functional Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5612, AE, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600, MB, Eindhoven, The Netherlands
| | - Danqing Liu
- Stimuli-responsive Functional Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5612, AE, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600, MB, Eindhoven, The Netherlands
| | - Joris Sprakel
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708, WE, Wageningen, The Netherlands.
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13
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Bhatt M, Moussu MAC, Chayer B, Destrempes F, Gesnik M, Allard L, Tang A, Cloutier G. Reconstruction of Viscosity Maps in Ultrasound Shear Wave Elastography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2019; 66:1065-1078. [PMID: 30990181 DOI: 10.1109/tuffc.2019.2908550] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Change in viscoelastic properties of biological tissues may often be symptomatic of a dysfunction that can be correlated to tissue pathology. Shear wave elastography is an imaging method mainly used to assess stiffness but with the potential to measure viscoelasticity of biological tissues. This can enable tissue characterization; and thus, can be used as a marker to improve diagnosis of pathological lesions. In this study, a frequency-shift method based framework is presented for the reconstruction of viscosity by analyzing the spectral properties of acoustic radiation force-induced shear waves. The aim of the study was to investigate the feasibility of viscosity reconstruction maps in homogeneous as well as heterogeneous samples. Experiments were performed in four in vitro phantoms, two ex vivo porcine liver samples, two ex vivo fatty duck liver samples, and one in vivo fatty goose liver. Successful viscosity maps were reconstructed in homogeneous and heterogeneous phantoms with embedded mechanical inclusions having different geometries. Quantitative values of viscosity obtained for two porcine liver tissues, two fatty duck liver samples, and one goose fatty liver were (mean ± SD) 0.61 ± 0.21, 0.52 ± 0.35; 1.28 ± 0.54, 1.36 ± 0.73, and 1.67 ± 0.70 Pa.s, respectively.
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14
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Nadkarni SK. Comprehensive Coagulation Profiling at the Point-of-Care Using a Novel Laser-Based Approach. Semin Thromb Hemost 2019; 45:264-274. [PMID: 30887486 DOI: 10.1055/s-0039-1683842] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Delays in identifying internal bleeding are life-threatening, thus underscoring the need for rapid and comprehensive coagulation profiling at the bedside. The authors review a novel optical coagulation profiler that measures several coagulation metrics including prothrombin time, activated clotting time, clot polymerization rate (α-angle), clot stiffness (maximum amplitude), fibrinolysis (LY), and platelet function, using a single multifunctional instrument. The optical profiler is based on the principles of Laser Speckle Rheology that quantifies tissue viscoelasticity from light scattering patterns called laser speckle. To operate the optical profiler, whole blood (40 μL) is loaded into a disposable cartridge, laser speckle patterns are recorded via a camera, and the viscoelasticity of clotting blood is estimated from speckle intensity fluctuations. By monitoring alterations in viscoelastic moduli over time during clot initiation, thrombin generation, fibrin crosslinking, clot stabilization, and LY, global coagulation parameters are obtained within 10 minutes using a drop of whole blood. Clinical testing in over 500 patients to date has confirmed the accuracy of the optical profiler for comprehensively assessing coagulation status against conventional coagulation tests and thromboelastography. Recent studies have further demonstrated the capability to quantify platelet aggregation induced by adenosine diphosphate in a drop of platelet-rich-plasma in the absence of applied shear stress. Together, these studies demonstrate that global coagulation profiling in addition to platelet function may be accomplished using a single multifunctional device. Thus, by enabling rapid and comprehensive coagulation and platelet function profiling at the bedside, the optical profiler will likely advance the capability to identify and manage patients with an elevated risk for hemorrhage.
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Affiliation(s)
- Seemantini K Nadkarni
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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15
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Yokoi N, Aizu Y, Uozumi J. Analysis of blood coagulation process based on fractality and dynamic characteristic of laser speckle pattern. JOURNAL OF BIOMEDICAL OPTICS 2018; 24:1-7. [PMID: 30569670 PMCID: PMC6975187 DOI: 10.1117/1.jbo.24.3.031018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
The reflection and transmission of coherent light from a biological system can yield information about its condition. In the case of blood exposed to the air, there is a change in the properties of the speckle patterns observed in the coagulation process. This can be studied by means of the rate of temporal variation, the contrast, and also the fractality of patterns. The fractality of the speckle pattern can be investigated by a fractal dimension, which can quantify a level of the complexity of platelet aggregation structure and a fibrin network formed in the process of blood coagulation. In addition, dynamic characteristics of a movement in blood also contain information on the progress of the coagulation process. Fractality and dynamic characteristics are investigated simultaneously for speckle patterns observed in the coagulation process of stored horse blood. Experimental results show the feasibility of the proposed method for detecting hemolysis and formation of platelet aggregation structure and the fibrin network during the coagulation process.
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Affiliation(s)
- Naomichi Yokoi
- National Institute of Technology, Asahikawa College, Department of Mechanical Systems Engineering, Asahikawa, Japan
| | - Yoshihisa Aizu
- Muroran Institute of Technology, College of Design and Manufacturing Technology, Muroran, Japan
| | - Jun Uozumi
- Hokkai-Gakuen University, Department of Electronics and Information Engineering, Sapporo, Japan
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16
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Jünger F, Rohrbach A. Strong cytoskeleton activity on millisecond timescales upon particle binding revealed by ROCS microscopy. Cytoskeleton (Hoboken) 2018; 75:410-424. [PMID: 30019494 DOI: 10.1002/cm.21478] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/05/2018] [Accepted: 07/10/2018] [Indexed: 01/09/2023]
Abstract
Cells change their shape within seconds, cellular protrusions even on subsecond timescales enabling various responses to stimuli of approaching bacteria, viruses or pharmaceutical drugs. Typical response patterns are governed by a complex reorganization of the actin cortex, where single filaments and molecules act on even faster timescales. These dynamics have remained mostly invisible due to a superposition of slow and fast motions, but also due to a lack of adequate imaging technology. Whereas fluorescence techniques require too long integration times, novel coherent techniques such as ROCS microscopy can achieve sufficiently high spatiotemporal resolution. ROCS uses rotating back-scattered laser light from cellular structures and generates a consistently high image contrast at 150 nm resolution and frame rates of 100 Hz-without fluorescence or bleaching. Here, we present an extension of ROCS microscopy that exploits the principles of dynamic light scattering for precise localization, visualization and quantification of the cytoskeleton activity of mouse macrophages. The locally observed structural reorganization processes, encoded by dynamic speckle patterns, occur upon distinct mechanical stimuli, such as soft contacts with optically trapped beads. We find that a substantial amount of the near-membrane cytoskeleton activity takes place on millisecond timescales, which is much faster than reported ever before.
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Affiliation(s)
- Felix Jünger
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, Freiburg, Germany
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17
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Wang S, Singh M, Tran TT, Leach J, Aglyamov SR, Larina IV, Martin JF, Larin KV. Biomechanical assessment of myocardial infarction using optical coherence elastography. BIOMEDICAL OPTICS EXPRESS 2018; 9:728-742. [PMID: 29552408 PMCID: PMC5854074 DOI: 10.1364/boe.9.000728] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 12/26/2017] [Accepted: 12/27/2017] [Indexed: 05/18/2023]
Abstract
Myocardial infarction (MI) leads to cardiomyocyte loss, impaired cardiac function, and heart failure. Molecular genetic analyses of myocardium in mouse models of ischemic heart disease have provided great insight into the mechanisms of heart regeneration, which is promising for novel therapies after MI. Although biomechanical factors are considered an important aspect in cardiomyocyte proliferation, there are limited methods for mechanical assessment of the heart in the mouse MI model. This prevents further understanding the role of tissue biomechanics in cardiac regeneration. Here we report optical coherence elastography (OCE) of the mouse heart after MI. Surgical ligation of the left anterior descending coronary artery was performed to induce an infarction in the heart. Two OCE methods with assessment of the direction-dependent elastic wave propagation and the spatially resolved displacement damping provide complementary analyses of the left ventricle. In comparison with sham, the infarcted heart features a fibrotic scar region with reduced elastic wave velocity, decreased natural frequency, and less mechanical anisotropy at the tissue level at the sixth week post-MI, suggesting lower and more isotropic stiffness. Our results indicate that OCE can be utilized for nondestructive biomechanical characterization of MI in the mouse model, which could serve as a useful tool in the study of heart repair.
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Affiliation(s)
- Shang Wang
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
- Equal contribution
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
- Equal contribution
| | - Thuy Tien Tran
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - John Leach
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - Salavat R. Aglyamov
- Department of Mechanical Engineering, University of Houston, 4726 Calhoun Road, Houston, Texas 77204, USA
| | - Irina V. Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - James F. Martin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
- The Texas Heart Institute, 6770 Bertner Avenue, Houston, Texas 77030, USA
| | - Kirill V. Larin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
- Interdisciplinary Laboratory of Biophotonics, Tomsk State University, 36 Lenin Ave., Tomsk 634050, Russia
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18
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Fang Q, Curatolo A, Wijesinghe P, Yeow YL, Hamzah J, Noble PB, Karnowski K, Sampson DD, Ganss R, Kim JK, Lee WM, Kennedy BF. Ultrahigh-resolution optical coherence elastography through a micro-endoscope: towards in vivo imaging of cellular-scale mechanics. BIOMEDICAL OPTICS EXPRESS 2017; 8:5127-5138. [PMID: 29188108 PMCID: PMC5695958 DOI: 10.1364/boe.8.005127] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/24/2017] [Accepted: 10/01/2017] [Indexed: 05/18/2023]
Abstract
In this paper, we describe a technique capable of visualizing mechanical properties at the cellular scale deep in living tissue, by incorporating a gradient-index (GRIN)-lens micro-endoscope into an ultrahigh-resolution optical coherence elastography system. The optical system, after the endoscope, has a lateral resolution of 1.6 µm and an axial resolution of 2.2 µm. Bessel beam illumination and Gaussian mode detection are used to provide an extended depth-of-field of 80 µm, which is a 4-fold improvement over a fully Gaussian beam case with the same lateral resolution. Using this system, we demonstrate quantitative elasticity imaging of a soft silicone phantom containing a stiff inclusion and a freshly excised malignant murine pancreatic tumor. We also demonstrate qualitative strain imaging below the tissue surface on in situ murine muscle. The approach we introduce here can provide high-quality extended-focus images through a micro-endoscope with potential to measure cellular-scale mechanics deep in tissue. We believe this tool is promising for studying biological processes and disease progression in vivo.
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Affiliation(s)
- Qi Fang
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, Western Australia 6009,
Australia
- School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Andrea Curatolo
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, Western Australia 6009,
Australia
- School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Philip Wijesinghe
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, Western Australia 6009,
Australia
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Yen Ling Yeow
- Targeted Drug Delivery, Imaging and Therapy, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Juliana Hamzah
- Targeted Drug Delivery, Imaging and Therapy, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Peter B. Noble
- School of Human Sciences, The University of Western Australia, Perth, Western Australia 6009,
Australia
- Centre for Neonatal Research & Education, School of Paediatrics and Child Health, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Karol Karnowski
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - David D. Sampson
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Western Australia 6009,
Australia
- Centre for Microscopy, Characterisation & Analysis, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Ruth Ganss
- Vascular Biology and Stromal Targeting, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, Western Australia 6009,
Australia
| | - Jun Ki Kim
- Biomedical Engineering Research Center, Asan Institute for Life Sciences, Asan Medical Center, and University of Ulsan College of Medicine, Seoul, 138-736,
South Korea
| | - Woei M. Lee
- Research School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra ACT 0200,
Australia
- The ARC Centre of Excellence in Advanced Molecular Imaging, The Australian National University, ACT 2601,
Australia
| | - Brendan F. Kennedy
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, Western Australia 6009,
Australia
- School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Western Australia 6009,
Australia
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19
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Tripathi MM, Egawa S, Wirth AG, Tshikudi DM, Van Cott EM, Nadkarni SK. Clinical evaluation of whole blood prothrombin time (PT) and international normalized ratio (INR) using a Laser Speckle Rheology sensor. Sci Rep 2017; 7:9169. [PMID: 28835607 PMCID: PMC5569083 DOI: 10.1038/s41598-017-08693-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 07/12/2017] [Indexed: 11/22/2022] Open
Abstract
Prothrombin time (PT) and the associated international normalized ratio (INR) are routinely tested to assess the risk of bleeding or thrombosis and to monitor response to anticoagulant therapy in patients. To measure PT/INR, conventional coagulation testing (CCT) is performed, which is time-consuming and requires the separation of cellular components from whole blood. Here, we report on a portable and battery-operated optical sensor that can rapidly quantify PT/INR within seconds by measuring alterations in the viscoelastic properties of a drop of whole blood following activation of coagulation with thromboplastin. In this study, PT/INR values were measured in 60 patients using the optical sensor and compared with the corresponding CCT values. Our results report a close correlation and high concordance between PT/INR measured using the two approaches. These findings confirm the accuracy of our optical sensing approach for rapid PT/INR testing in whole blood and highlight the potential for use at the point-of-care or for patient self-testing.
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Affiliation(s)
- Markandey M Tripathi
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Satoru Egawa
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, USA.,Department of Precision Engineering, University of Tokyo, Tokyo, Japan
| | - Alexandra G Wirth
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Diane M Tshikudi
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Elizabeth M Van Cott
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Seemantini K Nadkarni
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, USA.
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20
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Tshikudi DM, Tripathi MM, Hajjarian Z, Van Cott EM, Nadkarni SK. Optical sensing of anticoagulation status: Towards point-of-care coagulation testing. PLoS One 2017; 12:e0182491. [PMID: 28771571 PMCID: PMC5542647 DOI: 10.1371/journal.pone.0182491] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 07/19/2017] [Indexed: 11/18/2022] Open
Abstract
Anticoagulant overdose is associated with major bleeding complications. Rapid coagulation sensing may ensure safe and accurate anticoagulant dosing and reduce bleeding risk. Here, we report the novel use of Laser Speckle Rheology (LSR) for measuring anticoagulation and haemodilution status in whole blood. In the LSR approach, blood from 12 patients and 4 swine was placed in disposable cartridges and time-varying intensity fluctuations of laser speckle patterns were measured to quantify the viscoelastic modulus during clotting. Coagulation parameters, mainly clotting time, clot progression rate (α-angle) and maximum clot stiffness (MA) were derived from the clot viscoelasticity trace and compared with standard Thromboelastography (TEG). To demonstrate the capability for anticoagulation sensing in patients, blood samples from 12 patients treated with warfarin anticoagulant were analyzed. LSR clotting time correlated with prothrombin and activated partial thromboplastin time (r = 0.57-0.77, p<0.04) and all LSR parameters demonstrated good correlation with TEG (r = 0.61-0.87, p<0.04). To further evaluate the dose-dependent sensitivity of LSR parameters, swine blood was spiked with varying concentrations of heparin, argatroban and rivaroxaban or serially diluted with saline. We observed that anticoagulant treatments prolonged LSR clotting time in a dose-dependent manner that correlated closely with TEG (r = 0.99, p<0.01). LSR angle was unaltered by anticoagulation whereas TEG angle presented dose-dependent diminution likely linked to the mechanical manipulation of the clot. In both LSR and TEG, MA was largely unaffected by anticoagulation, and LSR presented a higher sensitivity to increased haemodilution in comparison to TEG (p<0.01). Our results establish that LSR rapidly and accurately measures the response of various anticoagulants, opening the opportunity for routine anticoagulation monitoring at the point-of-care or for patient self-testing.
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Affiliation(s)
- Diane M. Tshikudi
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Markandey M. Tripathi
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Zeinab Hajjarian
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Elizabeth M. Van Cott
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Seemantini K. Nadkarni
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
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21
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Hajjarian Z, Tshikudi DM, Nadkarni SK. Evaluating platelet aggregation dynamics from laser speckle fluctuations. BIOMEDICAL OPTICS EXPRESS 2017; 8:3502-3515. [PMID: 28717586 PMCID: PMC5508847 DOI: 10.1364/boe.8.003502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 06/25/2017] [Indexed: 05/16/2023]
Abstract
Platelets are key to maintaining hemostasis and impaired platelet aggregation could lead to hemorrhage or thrombosis. We report a new approach that exploits laser speckle intensity fluctuations, emanated from a drop of platelet-rich-plasma (PRP), to profile aggregation. Speckle fluctuation rate is quantified by the speckle intensity autocorrelation, g2(t), from which the aggregate size is deduced. We first apply this approach to evaluate polystyrene bead aggregation, triggered by salt. Next, we assess dose-dependent platelet aggregation and inhibition in human PRP spiked with adenosine diphosphate and clopidogrel. Additional spatio-temporal speckle analyses yield 2-dimensional maps of particle displacements to visualize platelet aggregate foci within minutes and quantify aggregation dynamics. These findings demonstrate the unique opportunity for assessing platelet health within minutes for diagnosing bleeding disorders and monitoring anti-platelet therapies.
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22
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Monroy GL, Pande P, Shelton RL, Nolan RM, Spillman D, Porter RG, Novak MA, Boppart SA. Non-invasive optical assessment of viscosity of middle ear effusions in otitis media. JOURNAL OF BIOPHOTONICS 2017; 10:394-403. [PMID: 27009636 PMCID: PMC5094900 DOI: 10.1002/jbio.201500313] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/24/2016] [Accepted: 03/01/2016] [Indexed: 05/03/2023]
Abstract
Eustachian tube dysfunction can cause fluid to collect within the middle ear cavity and form a middle ear effusion (MEE). MEEs can persist for weeks or months and cause hearing loss as well as speech and learning delays in young children. The ability of a physician to accurately identify and characterize the middle ear for signs of fluid and/or infection is crucial to provide the most appropriate treatment for the patient. Currently, middle ear infections are assessed with otoscopy, which provides limited and only qualitative diagnostic information. In this study, we propose a method utilizing cross-sectional depth-resolved optical coherence tomography to noninvasively measure the diffusion coefficient and viscosity of colloid suspensions, such as a MEE. Experimental validation of the proposed technique on simulated MEE phantoms with varying viscosity and particulate characteristics is presented, along with some preliminary results from in vivo and ex vivo samples of human MEEs. In vivo Optical Coherence Tomography (OCT) image of a human tympanic membrane and Middle Ear Effusion (MEE) (top), with a CCD image of the tympanic membrane surface (inset). Below is the corresponding time-lapse M-mode OCT data acquired along the white dotted line over time, which can be analyzed to determine the Stokes-Einstein diffusion coefficient of the effusion.
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Affiliation(s)
- Guillermo L. Monroy
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1270 Digital Computer Laboratory, MC-278, Urbana, IL 61801, USA
- Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, Urbana, IL 61801, USA
| | - Paritosh Pande
- Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, Urbana, IL 61801, USA
| | - Ryan L. Shelton
- Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, Urbana, IL 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 306 N. Wright St., Urbana, IL 61801
| | - Ryan M. Nolan
- Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, Urbana, IL 61801, USA
| | - Darold Spillman
- Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, Urbana, IL 61801, USA
| | - Ryan G. Porter
- Carle Foundation Hospital, Otolaryngology, 611 W. Park Street, Urbana, IL 61801
- College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Ave, Urbana, IL 61801
| | - Michael A. Novak
- Carle Foundation Hospital, Otolaryngology, 611 W. Park Street, Urbana, IL 61801
- College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Ave, Urbana, IL 61801
| | - Stephen A. Boppart
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1270 Digital Computer Laboratory, MC-278, Urbana, IL 61801, USA
- Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, Urbana, IL 61801, USA
- College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Ave, Urbana, IL 61801
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 306 N. Wright St., Urbana, IL 61801
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23
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Wang J, Hosoda M, Tshikudi DM, Hajjarian Z, Nadkarni SK. Intraluminal laser speckle rheology using an omni-directional viewing catheter. BIOMEDICAL OPTICS EXPRESS 2017; 8:137-150. [PMID: 28101407 PMCID: PMC5231287 DOI: 10.1364/boe.8.000137] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/04/2016] [Accepted: 12/05/2016] [Indexed: 05/27/2023]
Abstract
A number of disease conditions in luminal organs are associated with alterations in tissue mechanical properties. Here, we report a new omni-directional viewing Laser Speckle Rheology (LSR) catheter for mapping the mechanical properties of luminal organs without the need for rotational motion. The LSR catheter incorporates multiple illumination fibers, an optical fiber bundle and a multi-faceted mirror to permit omni-directional viewing of the luminal wall. By retracting the catheter using a motor-drive assembly, cylindrical maps of tissue mechanical properties are reconstructed. Evaluation conducted in a test phantom with circumferentially-varying mechanical properties demonstrates the capability of the LSR catheter for the accurate mechanical assessment of luminal organs.
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Affiliation(s)
- Jing Wang
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, MA 02114, USA
- Authors contributed equally to this work
| | - Masaki Hosoda
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, MA 02114, USA
- Healthcare Optics Research Laboratory, Canon U.S.A., Inc., Cambridge, MA 02139, USA
- Authors contributed equally to this work
| | - Diane M. Tshikudi
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, MA 02114, USA
| | - Zeinab Hajjarian
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, MA 02114, USA
| | - Seemantini K. Nadkarni
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, MA 02114, USA
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24
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Laser Speckle Rheology for evaluating the viscoelastic properties of hydrogel scaffolds. Sci Rep 2016; 6:37949. [PMID: 27905494 PMCID: PMC5131361 DOI: 10.1038/srep37949] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/02/2016] [Indexed: 11/08/2022] Open
Abstract
Natural and synthetic hydrogel scaffolds exhibit distinct viscoelastic properties at various length scales and deformation rates. Laser Speckle Rheology (LSR) offers a novel, non-contact optical approach for evaluating the frequency-dependent viscoelastic properties of hydrogels. In LSR, a coherent laser beam illuminates the specimen and a high-speed camera acquires the time-varying speckle images. Cross-correlation analysis of frames returns the speckle intensity autocorrelation function, g2(t), from which the frequency-dependent viscoelastic modulus, G*(ω), is deduced. Here, we establish the capability of LSR for evaluating the viscoelastic properties of hydrogels over a large range of moduli, using conventional mechanical rheometry and atomic force microscopy (AFM)-based indentation as reference-standards. Results demonstrate a strong correlation between |G*(ω)| values measured by LSR and mechanical rheometry (r = 0.95, p < 10−9), and z-test analysis reports that moduli values measured by the two methods are identical (p > 0.08) over a large range (47 Pa – 36 kPa). In addition, |G*(ω)| values measured by LSR correlate well with indentation moduli, E, reported by AFM (r = 0.92, p < 10−7). Further, spatially-resolved moduli measurements in micro-patterned substrates demonstrate that LSR combines the strengths of conventional rheology and micro-indentation in assessing hydrogel viscoelastic properties at multiple frequencies and small length-scales.
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25
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van der Kooij HM, Fokkink R, van der Gucht J, Sprakel J. Quantitative imaging of heterogeneous dynamics in drying and aging paints. Sci Rep 2016; 6:34383. [PMID: 27682840 PMCID: PMC5041151 DOI: 10.1038/srep34383] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 09/12/2016] [Indexed: 11/09/2022] Open
Abstract
Drying and aging paint dispersions display a wealth of complex phenomena that make their study fascinating yet challenging. To meet the growing demand for sustainable, high-quality paints, it is essential to unravel the microscopic mechanisms underlying these phenomena. Visualising the governing dynamics is, however, intrinsically difficult because the dynamics are typically heterogeneous and span a wide range of time scales. Moreover, the high turbidity of paints precludes conventional imaging techniques from reaching deep inside the paint. To address these challenges, we apply a scattering technique, Laser Speckle Imaging, as a versatile and quantitative tool to elucidate the internal dynamics, with microscopic resolution and spanning seven decades of time. We present a toolbox of data analysis and image processing methods that allows a tailored investigation of virtually any turbid dispersion, regardless of the geometry and substrate. Using these tools we watch a variety of paints dry and age with unprecedented detail.
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Affiliation(s)
- Hanne M van der Kooij
- Physical Chemistry and Soft Matter, Wageningen University &Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.,Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Remco Fokkink
- Physical Chemistry and Soft Matter, Wageningen University &Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Jasper van der Gucht
- Physical Chemistry and Soft Matter, Wageningen University &Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Joris Sprakel
- Physical Chemistry and Soft Matter, Wageningen University &Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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26
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Abstract
Fibrous structures are an integral and dynamic feature of soft biological tissues that are directly related to the tissues' condition and function. A greater understanding of mechanical tissue behavior can be gained through quantitative analyses of structure alone, as well as its integration into computational models of soft tissue function. Histology and other nonoptical techniques have traditionally dominated the field of tissue imaging, but they are limited by their invasiveness, inability to provide resolution on the micrometer scale, and dynamic information. Recent advances in optical modalities can provide higher resolution, less invasive imaging capabilities, and more quantitative measurements. Here we describe contemporary optical imaging techniques with respect to their suitability in the imaging of tissue structure, with a focus on characterization and implementation into subsequent modeling efforts. We outline the applications and limitations of each modality and discuss the overall shortcomings and future directions for optical imaging of soft tissue structure.
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Affiliation(s)
- Will Goth
- Department of Biomedical Engineering
| | - John Lesicko
- Department of Biomedical Engineering
- Center for Cardiovascular Simulation, and
| | - Michael S Sacks
- Department of Biomedical Engineering
- Center for Cardiovascular Simulation, and
- Institute for Computational Engineering and Sciences, University of Texas, Austin, Texas 78712;
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27
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Nader CA, Pellen F, Roquefort P, Aubry T, Le Jeune B, Le Brun G, Abboud M. Evaluation of low viscosity variations in fluids using temporal and spatial analysis of the speckle pattern. OPTICS LETTERS 2016; 41:2521-2524. [PMID: 27244404 DOI: 10.1364/ol.41.002521] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The noninvasive detection of a material's viscoelasticity is of great importance in the medical field. In fact, certain diseases cause changes in tissue structure and biological fluid viscosity; tracking those changes allows for detection of these diseases. Rheological measurements are also imperative in the industrial field, where it is necessary to characterize a material's viscoelasticity for manufacturing purposes. In this Letter, we present a noncontact, noninvasive, and low cost method for determining low viscosity values and variations in fluids. Laser speckle and viscometric measurements are performed on test samples having low scattering coefficients and low viscosities. The speckle spatial analysis proved to be as accurate as the speckle temporal correlation method reported in previous studies. Very low viscosities of the order of 1 mPa.s were retrieved for the first time using speckle images with either a frame rate of 1950 fps or a single acquired image.
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28
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Kennedy KM, Chin L, McLaughlin RA, Latham B, Saunders CM, Sampson DD, Kennedy BF. Quantitative micro-elastography: imaging of tissue elasticity using compression optical coherence elastography. Sci Rep 2015; 5:15538. [PMID: 26503225 PMCID: PMC4622092 DOI: 10.1038/srep15538] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/28/2015] [Indexed: 01/22/2023] Open
Abstract
Probing the mechanical properties of tissue on the microscale could aid in the identification of diseased tissues that are inadequately detected using palpation or current clinical imaging modalities, with potential to guide medical procedures such as the excision of breast tumours. Compression optical coherence elastography (OCE) maps tissue strain with microscale spatial resolution and can delineate microstructural features within breast tissues. However, without a measure of the locally applied stress, strain provides only a qualitative indication of mechanical properties. To overcome this limitation, we present quantitative micro-elastography, which combines compression OCE with a compliant stress sensor to image tissue elasticity. The sensor consists of a layer of translucent silicone with well-characterized stress-strain behaviour. The measured strain in the sensor is used to estimate the two-dimensional stress distribution applied to the sample surface. Elasticity is determined by dividing the stress by the strain in the sample. We show that quantification of elasticity can improve the ability of compression OCE to distinguish between tissues, thereby extending the potential for inter-sample comparison and longitudinal studies of tissue elasticity. We validate the technique using tissue-mimicking phantoms and demonstrate the ability to map elasticity of freshly excised malignant and benign human breast tissues.
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Affiliation(s)
- Kelsey M Kennedy
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
| | - Lixin Chin
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
| | - Robert A McLaughlin
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
| | - Bruce Latham
- PathWest, Fiona Stanley Hospital, Robin Warren Drive, Murdoch, WA 6150, Australia
| | - Christobel M Saunders
- School of Surgery, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,Breast Clinic, Royal Perth Hospital, 197 Wellington Street, Perth, WA 6000, Australia
| | - David D Sampson
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.,Centre for Microscopy, Characterisation &Analysis, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Brendan F Kennedy
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
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Hajjarian Z, Tripathi MM, Nadkarni SK. Optical Thromboelastography to evaluate whole blood coagulation. JOURNAL OF BIOPHOTONICS 2015; 8:372-81. [PMID: 24700701 PMCID: PMC4605542 DOI: 10.1002/jbio.201300197] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/07/2014] [Accepted: 03/15/2014] [Indexed: 05/12/2023]
Abstract
Measurement of blood viscoelasticity during clotting provides a direct metric of haemostatic conditions. Therefore, technologies that quantify blood viscoelasticity at the point-of-care are invaluable for diagnosing coagulopathies. We present a new approach, Optical Thromboelastography (OTEG) that measures the viscoelastic properties of coagulating blood by evaluating temporal laser speckle fluctuations, reflected from a few blood drops. During coagulation, platelet-fibrin clot formation restricts the mean square displacements (MSD) of scatterers and decelerates speckle fluctuations. Cross-correlation analysis of speckle frames provides the speckle intensity temporal autocorrelation, g2 (t), from which MSD is deduced and the viscoelastic modulus of blood is estimated. Our results demonstrate a close correspondence between blood viscoelasticity evaluated by OTEG and mechanical rheometry. Spatio-temporal speckle analyses yield 2-dimensional maps of clot viscoelasticity, enabling the identification of micro-clot formation at distinct rates in normal and coagulopathic specimens. These findings confirm the unique capability of OTEG for the rapid evaluation of patients' coagulation status and highlight the potential for point-of-care use.
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Affiliation(s)
- Zeinab Hajjarian
- Wellman Center For Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Markandey M Tripathi
- Wellman Center For Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Seemantini K Nadkarni
- Wellman Center For Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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30
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Hajjarian Z, Nadkarni SK. Estimation of particle size variations for laser speckle rheology of materials. OPTICS LETTERS 2015; 40:764-7. [PMID: 25723427 PMCID: PMC4605544 DOI: 10.1364/ol.40.000764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Laser speckle rheology (LSR) is an optical technique for assessing the viscoelastic properties of materials with several industrial, biological, and medical applications. In LSR, the viscoelastic modulus, G*(ω), of a material is quantified by analyzing the temporal fluctuations of speckle patterns. However, the size of scattering particles within the material also influences the rate of speckle fluctuations, independent of sample mechanical properties, and complicates the accurate estimation of G*(ω). Here, we demonstrate that the average particle size may be retrieved from the azimuth-angle dependence of time-averaged speckle intensities, permitting the accurate quantification of the viscoelastic moduli of materials with unknown particle size distribution using LSR.
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Affiliation(s)
- Zeinab Hajjarian
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, BAR-7, Boston, Massachusetts 02114, USA
| | - Seemantini K. Nadkarni
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, BAR-7, Boston, Massachusetts 02114, USA
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31
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Wang J, Nadkarni SK. The influence of optical fiber bundle parameters on the transmission of laser speckle patterns. OPTICS EXPRESS 2014; 22:8908-18. [PMID: 24787780 DOI: 10.1364/oe.22.008908] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Laser speckle imaging (LSI) techniques provide important functional information about tissue perfusion and mechanical properties. To perform LSI in vivo, laser speckle patterns are transmitted via optical fiber bundles incorporated within small-diameter endoscopes. Inter-fiber crosstalk due to mode coupling in fiber bundles can result in erroneous speckle statistics and therefore reduces the accuracy of LSI analysis. In this paper, we investigate the influence of multiple parameters that influence crosstalk between neighboring cores within optical fiber bundles and govern the modulation of transmitted laser speckle patterns. Our results show that in addition to large core-to-core separation, large refractive index contrast between core and cladding material, reduced number of propagating modes and variability in core size are essential parameters for accurate speckle pattern transmission to conduct endoscopic LSI.
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32
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Hajjarian Z, Nadkarni SK. Correction of optical absorption and scattering variations in Laser Speckle Rheology measurements. OPTICS EXPRESS 2014; 22:6349-61. [PMID: 24663983 PMCID: PMC4083052 DOI: 10.1364/oe.22.006349] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Laser Speckle Rheology (LSR) is an optical technique to evaluate the viscoelastic properties by analyzing the temporal fluctuations of backscattered speckle patterns. Variations of optical absorption and reduced scattering coefficients further modulate speckle fluctuations, posing a critical challenge for quantitative evaluation of viscoelasticity. We compare and contrast two different approaches applicable for correcting and isolating the collective influence of absorption and scattering, to accurately measure mechanical properties. Our results indicate that the numerical approach of Monte-Carlo ray tracing (MCRT) reliably compensates for any arbitrary optical variations. When scattering dominates absorption, yet absorption is non-negligible, diffusing wave spectroscopy (DWS) formalisms perform similar to MCRT, superseding other analytical compensation approaches such as Telegrapher equation. The computational convenience of DWS greatly simplifies the extraction of viscoelastic properties from LSR measurements in a number of chemical, industrial, and biomedical applications.
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33
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Tripathi MM, Hajjarian Z, Van Cott EM, Nadkarni SK. Assessing blood coagulation status with laser speckle rheology. BIOMEDICAL OPTICS EXPRESS 2014; 5:817-31. [PMID: 24688816 PMCID: PMC3959840 DOI: 10.1364/boe.5.000817] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/30/2013] [Accepted: 01/02/2014] [Indexed: 05/23/2023]
Abstract
We have developed and investigated a novel optical approach, Laser Speckle Rheology (LSR), to evaluate a patient's coagulation status by measuring the viscoelastic properties of blood during coagulation. In LSR, a blood sample is illuminated with laser light and temporal speckle intensity fluctuations are measured using a high-speed CMOS camera. During blood coagulation, changes in the viscoelastic properties of the clot restrict Brownian displacements of light scattering centers within the sample, altering the rate of speckle intensity fluctuations. As a result, blood coagulation status can be measured by relating the time scale of speckle intensity fluctuations with clinically relevant coagulation metrics including clotting time and fibrinogen content. Our results report a close correlation between coagulation metrics measured using LSR and conventional coagulation results of activated partial thromboplastin time, prothrombin time and functional fibrinogen levels, creating the unique opportunity to evaluate a patient's coagulation status in real-time at the point of care.
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Affiliation(s)
- Markandey M. Tripathi
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Zeinab Hajjarian
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Elizabeth M. Van Cott
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02144, USA
| | - Seemantini K. Nadkarni
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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Nadkarni SK. Optical measurement of arterial mechanical properties: from atherosclerotic plaque initiation to rupture. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:121507. [PMID: 24296995 PMCID: PMC4696609 DOI: 10.1117/1.jbo.18.12.121507] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 05/19/2023]
Abstract
During the pathogenesis of coronary atherosclerosis, from lesion initiation to rupture, arterial mechanical properties are altered by a number of cellular, molecular, and hemodynamic processes. There is growing recognition that mechanical factors may actively drive vascular cell signaling and regulate atherosclerosis disease progression. In advanced plaques, the mechanical properties of the atheroma influence stress distributions in the fibrous cap and mediate plaque rupture resulting in acute coronary events. This review paper explores current optical technologies that provide information on the mechanical properties of arterial tissue to advance our understanding of the mechanical factors involved in atherosclerosis development leading to plaque rupture. The optical approaches discussed include optical microrheology and traction force microscopy that probe the mechanical behavior of single cell and extracellular matrix components, and intravascular imaging modalities including laser speckle rheology, optical coherence elastography, and polarization-sensitive optical coherence tomography to measure the mechanical properties of advanced coronary lesions. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in elucidating the mechanical aspects of coronary atherosclerosis in the future.
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Affiliation(s)
- Seemantini K. Nadkarni
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts 02114
- Address all correspondence to: Seemantini K. Nadkarni, Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts 02114. Tel: (617)-724-1381; Fax: (617)-7264103; E-mail:
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35
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Evaluation and correction for optical scattering variations in laser speckle rheology of biological fluids. PLoS One 2013; 8:e65014. [PMID: 23705028 PMCID: PMC3660338 DOI: 10.1371/journal.pone.0065014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 04/22/2013] [Indexed: 11/19/2022] Open
Abstract
Biological fluids fulfill key functionalities such as hydrating, protecting, and nourishing cells and tissues in various organ systems. They are capable of these versatile tasks owing to their distinct structural and viscoelastic properties. Characterizing the viscoelastic properties of bio-fluids is of pivotal importance for monitoring the development of certain pathologies as well as engineering synthetic replacements. Laser Speckle Rheology (LSR) is a novel optical technology that enables mechanical evaluation of tissue. In LSR, a coherent laser beam illuminates the tissue and temporal speckle intensity fluctuations are analyzed to evaluate mechanical properties. The rate of temporal speckle fluctuations is, however, influenced by both optical and mechanical properties of tissue. Therefore, in this paper, we develop and validate an approach to estimate and compensate for the contributions of light scattering to speckle dynamics and demonstrate the capability of LSR for the accurate extraction of viscoelastic moduli in phantom samples and biological fluids of varying optical and mechanical properties.
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