51
|
Lauri J, Bykov A, Fabritius T. Quantification of cell-free layer thickness and cell distribution of blood by optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:40501. [PMID: 27071412 DOI: 10.1117/1.jbo.21.4.040501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/22/2016] [Indexed: 05/25/2023]
Abstract
A high-speed optical coherence tomography (OCT) with 1-μm 1-μm axial resolution was applied to assess the thickness of a cell-free layer (CFL) and a spatial distribution of red blood cells (RBC) next to the microchannel wall. The experiments were performed in vitro in a plain glass microchannel with a width of 2 mm and height of 0.2 mm. RBCs were suspended in phosphate buffered saline solution at the hematocrit level of 45%. Flow rates of 0.1 to 0.5 ml/h 0.5 ml/h were used to compensate gravity induced CFL. The results indicate that OCT can be efficiently used for the quantification of CFL thickness and spatial distribution of RBCs in microcirculatory blood flow.
Collapse
|
52
|
Ji L, Chen L, Wu P, Gervasio DF, Cai C. Highly Selective Fluorescence Determination of the Hematin Level in Human Erythrocytes with No Need for Separation from Bulk Hemoglobin. Anal Chem 2016; 88:3935-44. [DOI: 10.1021/acs.analchem.6b00131] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Lijuan Ji
- Jiangsu
Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation
Center of Biomedical Functional Materials, National and Local Joint
Engineering Research Center of Biomedical Functional Materials, College
of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, P. R. China
| | - Li Chen
- Jiangsu
Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation
Center of Biomedical Functional Materials, National and Local Joint
Engineering Research Center of Biomedical Functional Materials, College
of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, P. R. China
| | - Ping Wu
- Jiangsu
Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation
Center of Biomedical Functional Materials, National and Local Joint
Engineering Research Center of Biomedical Functional Materials, College
of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, P. R. China
| | - Dominic F. Gervasio
- Department of Chemical & Environmental Engineering, University of Arizona, 1133 East James E. Rogers Way, Tucson, Arizona 85721, United States
| | - Chenxin Cai
- Jiangsu
Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation
Center of Biomedical Functional Materials, National and Local Joint
Engineering Research Center of Biomedical Functional Materials, College
of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, P. R. China
| |
Collapse
|
53
|
Davis MA, Gagnon L, Boas DA, Dunn AK. Sensitivity of laser speckle contrast imaging to flow perturbations in the cortex. BIOMEDICAL OPTICS EXPRESS 2016; 7:759-75. [PMID: 27231587 PMCID: PMC4866454 DOI: 10.1364/boe.7.000759] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 05/18/2023]
Abstract
Laser speckle contrast imaging has become a ubiquitous tool for imaging blood flow in a variety of tissues. However, due to its widefield imaging nature, the measured speckle contrast is a depth integrated quantity and interpretation of baseline values and the depth dependent sensitivity of those values to changes in underlying flow has not been thoroughly evaluated. Using dynamic light scattering Monte Carlo simulations, the sensitivity of the autocorrelation function and speckle contrast to flow changes in the cerebral cortex was extensively examined. These simulations demonstrate that the sensitivity of the inverse autocorrelation time, [Formula: see text], varies across the field of view: directly over surface vessels [Formula: see text] is strongly localized to the single vessel, while parenchymal ROIs have a larger sensitivity to flow changes at depths up to 500 μm into the tissue and up to 200 μm lateral to the ROI. It is also shown that utilizing the commonly used models the relate [Formula: see text] to flow resulted in nearly the same sensitivity to the underlying flow, but fail to accurately relate speckle contrast values to absolute [Formula: see text].
Collapse
Affiliation(s)
- Mitchell A. Davis
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712,
USA
| | - Louis Gagnon
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129,
USA
| | - David A. Boas
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129,
USA
| | - Andrew K. Dunn
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712,
USA
| |
Collapse
|
54
|
Al-Rawhani MA, Beeley J, Cumming DRS. Wireless fluorescence capsule for endoscopy using single photon-based detection. Sci Rep 2015; 5:18591. [PMID: 26678456 PMCID: PMC4683524 DOI: 10.1038/srep18591] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 11/23/2015] [Indexed: 12/19/2022] Open
Abstract
Fluorescence Imaging (FI) is a powerful technique in biological science and clinical medicine. Current FI devices that are used either for in-vivo or in-vitro studies are expensive, bulky and consume substantial power, confining the technique to laboratories and hospital examination rooms. Here we present a miniaturised wireless fluorescence endoscope capsule with low power consumption that will pave the way for future FI systems and applications. With enhanced sensitivity compared to existing technology we have demonstrated that the capsule can be successfully used to image tissue autofluorescence and targeted fluorescence via fluorophore labelling of tissues. The capsule incorporates a state-of-the-art complementary metal oxide semiconductor single photon avalanche detector imaging array, miniaturised optical isolation, wireless technology and low power design. When in use the capsule consumes only 30.9 mW, and deploys very low-level 468 nm illumination. The device has the potential to replace highly power-hungry intrusive optical fibre based endoscopes and to extend the range of clinical examination below the duodenum. To demonstrate the performance of our capsule, we imaged fluorescence phantoms incorporating principal tissue fluorophores (flavins) and absorbers (haemoglobin). We also demonstrated the utility of marker identification by imaging a 20 μM fluorescein isothiocyanate (FITC) labelling solution on mammalian tissue.
Collapse
Affiliation(s)
| | - James Beeley
- School of Engineering, University of Glasgow, Oakfield Avenue, Glasgow G12 8LT, UK
| | - David R S Cumming
- School of Engineering, University of Glasgow, Oakfield Avenue, Glasgow G12 8LT, UK
| |
Collapse
|
55
|
Atamna H, Brahmbhatt M, Atamna W, Shanower GA, Dhahbi JM. ApoHRP-based assay to measure intracellular regulatory heme. Metallomics 2015; 7:309-21. [PMID: 25525887 DOI: 10.1039/c4mt00246f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The majority of the heme-binding proteins possess a "heme-pocket" that stably binds to heme. Usually known as housekeeping heme-proteins, they participate in a variety of metabolic reactions (e.g., catalase). Heme also binds with lower affinity to the "Heme-Regulatory Motifs" (HRM) in specific regulatory proteins. This type of heme binding is known as exchangeable or regulatory heme (RH). Heme binding to HRM proteins regulates their function (e.g., Bach1). Although there are well-established methods for assaying total cellular heme (e.g., heme-proteins plus RH), currently there is no method available for measuring RH independent of the total heme (TH). The current study describes and validates a new method to measure intracellular RH. This method is based on the reconstitution of apo-horseradish peroxidase (apoHRP) with heme to form holoHRP. The resulting holoHRP activity is then measured with a colorimetric substrate. The results show that apoHRP specifically binds RH but not with heme from housekeeping heme-proteins. The RH assay detects intracellular RH. Furthermore, using conditions that create positive (hemin) or negative (N-methyl protoporphyrin IX) controls for heme in normal human fibroblasts (IMR90), the RH assay shows that RH is dynamic and independent of TH. We also demonstrated that short-term exposure to subcytotoxic concentrations of lead (Pb), mercury (Hg), or amyloid-β (Aβ) significantly alters intracellular RH with little effect on TH. In conclusion the RH assay is an effective assay to investigate intracellular RH concentration and demonstrates that RH represents ∼6% of total heme in IMR90 cells.
Collapse
Affiliation(s)
- Hani Atamna
- Department of Basic Sciences, TCMC, Scranton, PA, USA
| | | | | | | | | |
Collapse
|
56
|
Yi J, Chen S, Shu X, Fawzi AA, Zhang HF. Human retinal imaging using visible-light optical coherence tomography guided by scanning laser ophthalmoscopy. BIOMEDICAL OPTICS EXPRESS 2015; 6:3701-13. [PMID: 26504622 PMCID: PMC4605031 DOI: 10.1364/boe.6.003701] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/21/2015] [Accepted: 08/23/2015] [Indexed: 05/18/2023]
Abstract
We achieved human retinal imaging using visible-light optical coherence tomography (vis-OCT) guided by an integrated scanning laser ophthalmoscopy (SLO). We adapted a spectral domain OCT configuration and used a supercontinuum laser as the illumating source. The center wavelength was 564 nm and the bandwidth was 115 nm, which provided a 0.97 µm axial resolution measured in air. We characterized the sensitivity to be 86 dB with 226 µW incidence power on the pupil. We also integrated an SLO that shared the same optical path of the vis-OCT sample arm for alignment purposes. We demonstrated the retinal imaging from both systems centered at the fovea and optic nerve head with 20° × 20° and 10° × 10° field of view. We observed similar anatomical structures in vis-OCT and NIR-OCT. The contrast appeared different from vis-OCT to NIR-OCT, including slightly weaker signal from intra-retinal layers, and increased visibility and contrast of anatomical layers in the outer retina.
Collapse
Affiliation(s)
- Ji Yi
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- These authors contributed equally to this work
| | - Siyu Chen
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- These authors contributed equally to this work
| | - Xiao Shu
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- These authors contributed equally to this work
| | - Amani A. Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Ave, Chicago, IL 60611 USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Ave, Chicago, IL 60611 USA
| |
Collapse
|
57
|
Chen C, Florian K, Rajesh K, Max R, Christian K, Florian S, Michael S. Recovering the superficial microvascular pattern via diffuse reflection imaging: phantom validation. Biomed Eng Online 2015; 14:87. [PMID: 26419826 PMCID: PMC4589028 DOI: 10.1186/s12938-015-0081-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 09/03/2015] [Indexed: 11/26/2022] Open
Abstract
Background Diffuse reflection imaging could potentially be used to recover the superficial microvasculature under cutaneous tissue and the associated blood oxygenation status with a modified imaging resolution. The aim of this work is to deliver a new approach of local off-axis scanning diffuse reflection imaging, with the revisit of the modified Beer–Lambert Law (MBLL). Methods To validate this, the system is used to recover the micron-scale subsurface vessel structure interiorly embedded in a skin equivalent tissue phantom. This vessel structure is perfused with oxygenated meta-hemoglobin solution. Results Our preliminary results confirm that the thin vessel structure can be mapped into a 2-D planar image. The distributions of oxygenated hemoglobin concentration (\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$Ct_{HbO_{2}}$$\end{document}CtHbO2) and deoxygenated hemoglobin concentration (\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$Ct_{RHb}$$\end{document}CtRHb) can be co-registerated through the MBLL upon the CW spectroscopy, the scattering issue is addressed in the reformed MBLL. The recovered pattern matches to the estimation from the simultaneous optical coherence tomography studies. Conclusions With further modification, this system may serve as the first prototype to investigate the superficial microvasculature in the expotential skin cancer loci, or a micro-lesion of vascular dermatosis.
Collapse
Affiliation(s)
- Chen Chen
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany. .,Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052, Erlangen, Germany.
| | - Klämpfl Florian
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany.
| | - Kanawade Rajesh
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany. .,Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052, Erlangen, Germany.
| | - Riemann Max
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Glück Str. 11, 91054, Erlangen, Germany.
| | - Knipfer Christian
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Glück Str. 11, 91054, Erlangen, Germany.
| | - Stelzle Florian
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Glück Str. 11, 91054, Erlangen, Germany.
| | - Schmidt Michael
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany. .,Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052, Erlangen, Germany.
| |
Collapse
|
58
|
Chen S, Yi J, Zhang HF. Measuring oxygen saturation in retinal and choroidal circulations in rats using visible light optical coherence tomography angiography. BIOMEDICAL OPTICS EXPRESS 2015; 6:2840-53. [PMID: 26309748 PMCID: PMC4541512 DOI: 10.1364/boe.6.002840] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/30/2015] [Accepted: 07/06/2015] [Indexed: 05/20/2023]
Abstract
Visible light optical coherence tomography (vis-OCT) has demonstrated its capability of measuring vascular oxygen saturation (sO2) in vivo. Enhanced by OCT angiography, the signal from microvasculature can be further isolated and directly used for sO2 extraction. In this work, we extended the theoretical formulation for OCT angiography-based oximetry by incorporating the contribution from motion contrast enhancement. We presented a new method to eliminate the associated confounding variables due to blood flow. First, we performed in vitro experiments to verify our theory, showing a stable spectral derivative within the selected wavelength bands for sO2 extraction. Then, we tested our method in vivo to measure retinal sO2 in rats inhaling different gas mixtures: normal air, 5% CO2, pure O2, and 10% O2. Absolute sO2 values in major arterioles and venules in the retinal circulation can be accurately measured. In addition, we demonstrated the relative changes of sO2 can be measured non-invasively from choriocapillaris immediately underneath the retinal pigmented epithelium (RPE) in rodents.
Collapse
Affiliation(s)
- Siyu Chen
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd. Evanston, IL 60208 USA
- These authors contributed equally to this work
| | - Ji Yi
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd. Evanston, IL 60208 USA
- These authors contributed equally to this work
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd. Evanston, IL 60208 USA
- Department of Ophthalmology, Northwestern University, 2145 Sheridan Rd., Evanston 60208, USA
| |
Collapse
|
59
|
Kim J, Brown W, Maher JR, Levinson H, Wax A. Functional optical coherence tomography: principles and progress. Phys Med Biol 2015; 60:R211-37. [PMID: 25951836 PMCID: PMC4448140 DOI: 10.1088/0031-9155/60/10/r211] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In the past decade, several functional extensions of optical coherence tomography (OCT) have emerged, and this review highlights key advances in instrumentation, theoretical analysis, signal processing and clinical application of these extensions. We review five principal extensions: Doppler OCT (DOCT), polarization-sensitive OCT (PS-OCT), optical coherence elastography (OCE), spectroscopic OCT (SOCT), and molecular imaging OCT. The former three have been further developed with studies in both ex vivo and in vivo human tissues. This review emphasizes the newer techniques of SOCT and molecular imaging OCT, which show excellent potential for clinical application but have yet to be well reviewed in the literature. SOCT elucidates tissue characteristics, such as oxygenation and carcinogenesis, by detecting wavelength-dependent absorption and scattering of light in tissues. While SOCT measures endogenous biochemical distributions, molecular imaging OCT detects exogenous molecular contrast agents. These newer advances in functional OCT broaden the potential clinical application of OCT by providing novel ways to understand tissue activity that cannot be accomplished by other current imaging methodologies.
Collapse
Affiliation(s)
- Jina Kim
- Department of Surgery, Duke University, Durham, NC 27710, USA
| | | | | | | | | |
Collapse
|
60
|
Chen S, Yi J, Liu W, Backman V, Zhang HF. Monte Carlo Investigation of Optical Coherence Tomography Retinal Oximetry. IEEE Trans Biomed Eng 2015; 62:2308-15. [PMID: 25955984 DOI: 10.1109/tbme.2015.2424689] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Optical coherence tomography (OCT) oximetry explores the possibility to measure retinal hemoglobin oxygen saturation level (sO2). We investigated the accuracy of OCT retinal oximetry using Monte Carlo simulation in a commonly used four-layer retinal model. After we determined the appropriate number of simulated photon packets, we studied the effects of blood vessel diameter, signal sampling position, physiological sO2 level, and the blood packing factor on the accuracy of sO2 estimation in OCT retinal oximetry. The simulation results showed that a packing factor between 0.2 and 0.4 yields a reasonably accurate estimation of sO2 within a 5% error tolerance, which is independent of vessel diameter and sampling position, when visible-light illumination is used in OCT. We further explored the optimal optical spectral range for OCT retinal oximetry. The simulation results suggest that visible spectral range around 560 nm is better suited than near-infrared spectral range around 800 nm for OCT oximetry to warrant accurate measurements.
Collapse
|
61
|
Chong SP, Merkle CW, Leahy C, Radhakrishnan H, Srinivasan VJ. Quantitative microvascular hemoglobin mapping using visible light spectroscopic Optical Coherence Tomography. BIOMEDICAL OPTICS EXPRESS 2015; 6:1429-50. [PMID: 25909026 PMCID: PMC4399681 DOI: 10.1364/boe.6.001429] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/19/2015] [Accepted: 03/14/2015] [Indexed: 05/18/2023]
Abstract
Quantification of chromophore concentrations in reflectance mode remains a major challenge for biomedical optics. Spectroscopic Optical Coherence Tomography (SOCT) provides depth-resolved spectroscopic information necessary for quantitative analysis of chromophores, like hemoglobin, but conventional SOCT analysis methods are applicable only to well-defined specular reflections, which may be absent in highly scattering biological tissue. Here, by fitting of the dynamic scattering signal spectrum in the OCT angiogram using a forward model of light propagation, we quantitatively determine hemoglobin concentrations directly. Importantly, this methodology enables mapping of both oxygen saturation and total hemoglobin concentration, or alternatively, oxyhemoglobin and deoxyhemoglobin concentration, simultaneously. Quantification was verified by ex vivo blood measurements at various pO2 and hematocrit levels. Imaging results from the rodent brain and retina are presented. Confounds including noise and scattering, as well as potential clinical applications, are discussed.
Collapse
|
62
|
Kabbua T, Anwised P, Boonmee A, Subedi BP, Pierce BS, Thammasirirak S. Autoinduction, purification, and characterization of soluble α-globin chains of crocodile (Crocodylus siamensis) hemoglobin in Escherichia coli. Protein Expr Purif 2014; 103:56-63. [DOI: 10.1016/j.pep.2014.08.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/19/2014] [Accepted: 08/20/2014] [Indexed: 01/30/2023]
|
63
|
Maher JR, Jaedicke V, Medina M, Levinson H, Selim MA, Brown WJ, Wax A. In vivo analysis of burns in a mouse model using spectroscopic optical coherence tomography. OPTICS LETTERS 2014; 39:5594-7. [PMID: 25360936 PMCID: PMC4370176 DOI: 10.1364/ol.39.005594] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Spectroscopic analysis of biological tissues can provide insight into changes in structure and function due to disease or injury. Depth-resolved spectroscopic measurements can be implemented for tissue imaging using optical coherence tomography (OCT). Here, spectroscopic OCT is applied to in vivo measurement of burn injury in a mouse model. Data processing and analysis methods are compared for their accuracy. Overall accuracy in classifying burned tissue was found to be as high as 91%, producing an area under the curve of a receiver operating characteristic curve of 0.97. The origins of the spectral changes are identified by correlation with histopathology.
Collapse
Affiliation(s)
- Jason R. Maher
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
| | - Volker Jaedicke
- Photonics and Terahertz Technology, Ruhr-Universität Bochum, Universitätsstr 150, 44780 Bochum, Germany
| | - Manuel Medina
- Department of Surgery, Duke University Medical Center, Durham, NC 27708
| | - Howard Levinson
- Department of Surgery, Duke University Medical Center, Durham, NC 27708
- Department of Pathology, Duke University Medical Center, Durham, NC 27708
| | | | - William J. Brown
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
- Corresponding author:
| |
Collapse
|
64
|
Steppan J, Hogue CW. Cerebral and tissue oximetry. Best Pract Res Clin Anaesthesiol 2014; 28:429-39. [PMID: 25480772 DOI: 10.1016/j.bpa.2014.09.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 09/10/2014] [Accepted: 09/16/2014] [Indexed: 01/20/2023]
Abstract
The use of near-infrared spectroscopy (NIRS) has been increasingly adopted in cardiac surgery to measure regional cerebral oxygen saturation. This method takes advantage of the fact that light in the near-infrared spectrum penetrates tissue, including bone and muscle. Sensors are placed at fixed distances from a light emitter, and algorithms subtract superficial light absorption from deep absorption to provide an index of tissue oxygenation. Although the popularity of NIRS monitoring is growing, definitive data that prove outcome benefits with its use remain sparse. Therefore, widespread, routine use of NIRS as a standard-of-care monitor cannot be recommended at present. Recent investigations have focused on the use of NIRS in subgroups that may benefit from NIRS monitoring, such as pediatric patients. Furthermore, a novel application of processed NIRS information for monitoring cerebral autoregulation and tissue oxygenation (e.g., kidneys and the gut) is promising.
Collapse
Affiliation(s)
- Jochen Steppan
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Charles W Hogue
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.
| |
Collapse
|
65
|
Jung J, Kim K, Yu H, Lee K, Lee S, Nahm S, Park H, Park Y. Biomedical applications of holographic microspectroscopy [invited]. APPLIED OPTICS 2014; 53:G111-22. [PMID: 25322118 DOI: 10.1364/ao.53.00g111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The identification and quantification of specific molecules are crucial for studying the pathophysiology of cells, tissues, and organs as well as diagnosis and treatment of diseases. Recent advances in holographic microspectroscopy, based on quantitative phase imaging or optical coherence tomography techniques, show promise for label-free noninvasive optical detection and quantification of specific molecules in living cells and tissues (e.g., hemoglobin protein). To provide important insight into the potential employment of holographic spectroscopy techniques in biological research and for related practical applications, we review the principles of holographic microspectroscopy techniques and highlight recent studies.
Collapse
|
66
|
Davis MA, Kazmi SMS, Dunn AK. Imaging depth and multiple scattering in laser speckle contrast imaging. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086001. [PMID: 25089945 PMCID: PMC4119427 DOI: 10.1117/1.jbo.19.8.086001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/15/2014] [Accepted: 06/23/2014] [Indexed: 05/18/2023]
Abstract
Laser speckle contrast imaging (LSCI) is a powerful and simple method for full field imaging of blood flow. However, the depth dependence and the degree of multiple scattering have not been thoroughly investigated. We employ three-dimensional Monte Carlo simulations of photon propagation combined with high resolution vascular anatomy to investigate these two issues. We found that 95% of the detected signal comes from the top 700 μm of tissue. Additionally, we observed that single-intravascular scattering is an accurate description of photon sampling dynamics, but that regions of interest (ROIs) in areas free of obvious surface vessels had fewer intravascular scattering events than ROI over resolved surface vessels. Furthermore, we observed that the local vascular anatomy can strongly affect the depth dependence of LSCI. We performed simulations over a wide range of intravascular and extravascular scattering properties to confirm the applicability of these results to LSCI imaging over a wide range of visible and near-infrared wavelengths.
Collapse
Affiliation(s)
- Mitchell A. Davis
- The University of Texas at Austin, Department of Electrical and Computer Engineering, Austin, Texas 78712, United States
| | - S. M. Shams Kazmi
- The University of Texas at Austin, Department of Biomedical Engineering, Austin, Texas 78712, United States
| | - Andrew K. Dunn
- The University of Texas at Austin, Department of Biomedical Engineering, Austin, Texas 78712, United States
- Address all correspondence to: Andrew K. Dunn, E-mail:
| |
Collapse
|
67
|
Tsai TH, Fujimoto JG, Mashimo H. Endoscopic Optical Coherence Tomography for Clinical Gastroenterology. Diagnostics (Basel) 2014; 4:57-93. [PMID: 26852678 PMCID: PMC4665545 DOI: 10.3390/diagnostics4020057] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 04/18/2014] [Accepted: 04/22/2014] [Indexed: 12/12/2022] Open
Abstract
Optical coherence tomography (OCT) is a real-time optical imaging technique that is similar in principle to ultrasonography, but employs light instead of sound waves and allows depth-resolved images with near-microscopic resolution. Endoscopic OCT allows the evaluation of broad-field and subsurface areas and can be used ancillary to standard endoscopy, narrow band imaging, chromoendoscopy, magnification endoscopy, and confocal endomicroscopy. This review article will provide an overview of the clinical utility of endoscopic OCT in the gastrointestinal tract and of recent achievements using state-of-the-art endoscopic 3D-OCT imaging systems.
Collapse
Affiliation(s)
- Tsung-Han Tsai
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - James G Fujimoto
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Hiroshi Mashimo
- Veterans Affairs Boston Healthcare System and Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
68
|
Yi J, Radosevich AJ, Stypula-Cyrus Y, Mutyal NN, Azarin SM, Horcher E, Goldberg MJ, Bianchi LK, Bajaj S, Roy HK, Backman V. Spatially resolved optical and ultrastructural properties of colorectal and pancreatic field carcinogenesis observed by inverse spectroscopic optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:36013. [PMID: 24643530 PMCID: PMC4019430 DOI: 10.1117/1.jbo.19.3.036013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 02/13/2014] [Accepted: 02/17/2014] [Indexed: 05/18/2023]
Abstract
Field carcinogenesis is the initial stage of cancer progression. Understanding field carcinogenesis is valuable for both cancer biology and clinical medicine. Here, we used inverse spectroscopic optical coherence tomography to study colorectal cancer (CRC) and pancreatic cancer (PC) field carcinogenesis. Depth-resolved optical and ultrastructural properties of the mucosa were quantified from histologically normal rectal biopsies from patients with and without colon adenomas (n=85) as well as from histologically normal peri-ampullary duodenal biopsies from patients with and without PC (n=22). Changes in the epithelium and stroma in CRC field carcinogenesis were separately quantified. In both compartments, optical and ultra-structural alterations were consistent. Optical alterations included lower backscattering (μb) and reduced scattering (μs') coefficients and higher anisotropy factor g. Ultrastructurally pronounced alterations were observed at length scales up to ∼450 nm, with the shape of the mass density correlation function having a higher shape factor D, thus implying a shift to larger length scales. Similar alterations were found in the PC field carcinogenesis despite the difference in genetic pathways and etiologies. We further verified that the chromatin clumping in epithelial cells and collagen cross-linking caused D to increase in vitro and could be among the mechanisms responsible for the observed changes in epithelium and stroma, respectively.
Collapse
Affiliation(s)
- Ji Yi
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Andrew J. Radosevich
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Yolanda Stypula-Cyrus
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Nikhil N. Mutyal
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Samira Michelle Azarin
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Elizabeth Horcher
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Michael J. Goldberg
- NorthShore University Health Systems, Department of Internal Medicine, Evanston, Illinois 60201
| | - Laura K. Bianchi
- NorthShore University Health Systems, Department of Internal Medicine, Evanston, Illinois 60201
| | - Shailesh Bajaj
- NorthShore University Health Systems, Department of Internal Medicine, Evanston, Illinois 60201
| | - Hemant K. Roy
- Boston Medical Center, Department of Medicine, Boston, Massachusetts 02118
| | - Vadim Backman
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208
- Address all correspondence to: Vadim Backman, E-mail:
| |
Collapse
|
69
|
Jung JH, Jang J, Park Y. Spectro-refractometry of individual microscopic objects using swept-source quantitative phase imaging. Anal Chem 2013; 85:10519-25. [PMID: 24079982 DOI: 10.1021/ac402521u] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We present a novel spectroscopic quantitative phase imaging technique with a wavelength swept-source, referred to as swept-source diffraction phase microscopy (ssDPM), for quantifying the optical dispersion of microscopic individual samples. Employing the swept-source and the principle of common-path interferometry, ssDPM measures the multispectral full-field quantitative phase imaging and spectroscopic microrefractometry of transparent microscopic samples in the visible spectrum with a wavelength range of 450-750 nm and a spectral resolution of less than 8 nm. With unprecedented precision and sensitivity, we demonstrate the quantitative spectroscopic microrefractometry of individual polystyrene beads, 30% bovine serum albumin solution, and healthy human red blood cells.
Collapse
Affiliation(s)
- Jae-Hwang Jung
- Department of Physics, Korea Advanced Institute of Science and Technology , Daejeon 305-701, South Korea
| | | | | |
Collapse
|
70
|
Hart VP, Doyle TE. Simulation of diffuse photon migration in tissue by a Monte Carlo method derived from the optical scattering of spheroids. APPLIED OPTICS 2013; 52:6220-6229. [PMID: 24085080 DOI: 10.1364/ao.52.006220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 07/29/2013] [Indexed: 06/02/2023]
Abstract
A Monte Carlo method was derived from the optical scattering properties of spheroidal particles and used for modeling diffuse photon migration in biological tissue. The spheroidal scattering solution used a separation of variables approach and numerical calculation of the light intensity as a function of the scattering angle. A Monte Carlo algorithm was then developed which utilized the scattering solution to determine successive photon trajectories in a three-dimensional simulation of optical diffusion and resultant scattering intensities in virtual tissue. Monte Carlo simulations using isotropic randomization, Henyey-Greenstein phase functions, and spherical Mie scattering were additionally developed and used for comparison to the spheroidal method. Intensity profiles extracted from diffusion simulations showed that the four models differed significantly. The depth of scattering extinction varied widely among the four models, with the isotropic, spherical, spheroidal, and phase function models displaying total extinction at depths of 3.62, 2.83, 3.28, and 1.95 cm, respectively. The results suggest that advanced scattering simulations could be used as a diagnostic tool by distinguishing specific cellular structures in the diffused signal. For example, simulations could be used to detect large concentrations of deformed cell nuclei indicative of early stage cancer. The presented technique is proposed to be a more physical description of photon migration than existing phase function methods. This is attributed to the spheroidal structure of highly scattering mitochondria and elongation of the cell nucleus, which occurs in the initial phases of certain cancers. The potential applications of the model and its importance to diffusive imaging techniques are discussed.
Collapse
|
71
|
Yi J, Wei Q, Liu W, Backman V, Zhang HF. Visible-light optical coherence tomography for retinal oximetry. OPTICS LETTERS 2013; 38:1796-8. [PMID: 23722747 PMCID: PMC3986589 DOI: 10.1364/ol.38.001796] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We applied a visible-light spectroscopic optical coherence tomography (vis-OCT) for in vivo retinal oximetry. To extract hemoglobin oxygen saturation (sO(2)) in individual retinal vessels, we established a comprehensive analytical model to describe optical absorption, optical scattering, and blood cell packing factor in the whole blood and fit the acquired vis-OCT signals from the bottom of each imaged vessel. We found that averaged sO(2) values in arterial and venous bloods were 95% and 72%, respectively.
Collapse
Affiliation(s)
- Ji Yi
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Qing Wei
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Wenzhong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Department of Ophthalmology, Northwestern University, Chicago, Illinois 60611, USA
| |
Collapse
|
72
|
Liu W, Jiao S, Zhang HF. Accuracy of retinal oximetry: a Monte Carlo investigation. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:066003. [PMID: 23733019 PMCID: PMC3669519 DOI: 10.1117/1.jbo.18.6.066003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Retinal hemoglobin oxygen saturation (sO2) level is believed to be associated with the pathophysiology of several leading blinding diseases. Methods to properly measure retinal sO2 have been investigated for decades; however, the accuracy of retinal oximetry is still considered to be limited. The Monte Carlo simulation of photon transport in retina to examine how the accuracy of retinal oximetry is affected by local parameters is discussed. Fundus photography was simulated in a multilayer retinal model, in which a single vessel segment with 0.7 sO2 was embedded, at six optical wavelengths. Then, 200 million photons were traced in each simulation to ensure statistically stable results. The optical reflectance and energy deposit were recorded to measure sO2 using both the reflection method (existing retinal oximetry) and a new absorption method, photoacoustic ophthalmoscopy (PAOM). By varying the vessel diameter and melanin concentration in the retinal pigment epithelium, the relative error of sO2 measurement in the reflection method increased with increasing vessel diameter and melanin concentration; in comparison, the sO2 measurement was insensitive to these two parameters in PAOM. The results suggest that PAOM potentially can be a more accurate tool in quantifying retinal sO2.
Collapse
Affiliation(s)
- Wenzhong Liu
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois 60208
| | - Shuliang Jiao
- Florida International University, Department of Biomedical Engineering, Miami, Florida 33174
| | - Hao F. Zhang
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois 60208
- Northwestern University, Department of Ophthalmology, Chicago, Illinois 60611
- Address all correspondence to: Hao F. Zhang, Northwestern University, Department of Biomedical Engineering, Evanston, Illinois 60208. Tel: 847-491-2946; Fax: 847-491-4928; E-mail:
| |
Collapse
|
73
|
Kim S, Rinehart MT, Park H, Zhu Y, Wax A. Phase-sensitive OCT imaging of multiple nanoparticle species using spectrally multiplexed single pulse photothermal excitation. BIOMEDICAL OPTICS EXPRESS 2012; 3:2579-86. [PMID: 23082297 PMCID: PMC3470000 DOI: 10.1364/boe.3.002579] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/02/2012] [Accepted: 09/13/2012] [Indexed: 05/24/2023]
Abstract
We apply phase-sensitive optical coherence tomography to image multiple nanoparticle species with two excitation wavelengths matched to their distinct absorption peaks. Using different modulation frequencies, multiple species collocated within the sample can be distinguished. In addition, we characterize single-pulse excitation schemes as a method to minimize bulk heating of the sample. We demonstrate this new scheme with B-mode photothermal measurements of tissue phantoms.
Collapse
|
74
|
Li YL, Seekell K, Yuan H, Robles FE, Wax A. Multispectral nanoparticle contrast agents for true-color spectroscopic optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2012; 3:1914-23. [PMID: 22876354 PMCID: PMC3409709 DOI: 10.1364/boe.3.001914] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 05/18/2023]
Abstract
We have recently developed a novel dual window scheme for processing spectroscopic OCT images to provide spatially resolved true color imaging of chromophores in scattering samples. Here we apply this method to measure the extinction spectra of plasmonic nanoparticles at various concentrations for potential in vivo applications. We experimentally demonstrate sub-nanomolar sensitivity in the measurement of nanoparticle concentrations, and show that colorimetric imaging with multiple species of nanoparticles produces enhanced contrast for spectroscopic OCT in both tissue phantom and cell studies.
Collapse
Affiliation(s)
- You Leo Li
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| | - Kevin Seekell
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| | - Hsiangkuo Yuan
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| | | | - Adam Wax
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| |
Collapse
|
75
|
Rinehart M, Zhu Y, Wax A. Quantitative phase spectroscopy. BIOMEDICAL OPTICS EXPRESS 2012; 3:958-65. [PMID: 22567588 PMCID: PMC3342200 DOI: 10.1364/boe.3.000958] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 04/05/2012] [Accepted: 04/10/2012] [Indexed: 05/18/2023]
Abstract
Quantitative phase spectroscopy is presented as a novel method of measuring the wavelength-dependent refractive index of microscopic volumes. Light from a broadband source is filtered to an ~5 nm bandwidth and rapidly tuned across the visible spectrum in 1 nm increments by an acousto-optic tunable filter (AOTF). Quantitative phase images of semitransparent samples are recovered at each wavelength using off-axis interferometry and are processed to recover relative and absolute dispersion measurements. We demonstrate the utility of this approach by (i) spectrally averaging phase images to reduce coherent noise, (ii) measuring absorptive and dispersive features in microspheres, and (iii) quantifying bulk hemoglobin concentrations by absolute refractive index measurements. Considerations of using low coherence illumination and the extension of spectral techniques in quantitative phase measurements are discussed.
Collapse
|
76
|
Bosschaart N, Kok JH, Newsum AM, Ouweneel DM, Mentink R, van Leeuwen TG, Aalders MCG. Limitations and opportunities of transcutaneous bilirubin measurements. Pediatrics 2012; 129:689-94. [PMID: 22430456 DOI: 10.1542/peds.2011-2586] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Although transcutaneous bilirubinometers have existed for over 30 years, the clinical utility of the technique is limited to a screening method for hyperbilirubinemia, rather than a replacement for invasive blood sampling. In this study, we investigate the reason for this limited clinical value and address possibilities for improvement. METHODS To obtain better insight into the physiology of bilirubin measurements, we evaluated a transcutaneous bilirubinometer that determines not only the cutaneous bilirubin concentration (TcB) but also the blood volume fraction (BVF) in the investigated skin volume. For 49 neonates (gestational age 30 ± 3.1 weeks, postnatal age 6 [4-10] days) at our NICU, we performed 124 TcB and 55 BVF measurements. RESULTS The TcB correlated well with the total serum bilirubin concentration (TSB) (r = 0.88) with an uncertainty of 55 µmol/L. The BVF in the measured skin volume ranged between 0.1% and 0.75%. CONCLUSIONS The performance of our bilirubinometer is comparable to existing transcutaneous devices. The limited clinical value of current bilirubinometers can be explained by the low BVF in the skin volume that is probed by these devices. Because the TcB depends for over 99% on the contribution of extravascular bilirubin, it is a physiologically different parameter from the TSB. Hence, the standard method of evaluation that compares the TcB to the TSB is insufficient to fully investigate the clinical value of transcutaneous bilirubinometers, ie, their predictive value for kernicterus. We suggest that the clinical value may be improved considerably by changing either the method of evaluation or the technological design of transcutaneous bilirubinometers.
Collapse
Affiliation(s)
- Nienke Bosschaart
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.
| | | | | | | | | | | | | |
Collapse
|
77
|
Davis MA, Shams Kazmi SM, Ponticorvo A, Dunn AK. Depth dependence of vascular fluorescence imaging. BIOMEDICAL OPTICS EXPRESS 2011; 2:3349-62. [PMID: 22162824 PMCID: PMC3233253 DOI: 10.1364/boe.2.003349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/01/2011] [Accepted: 11/15/2011] [Indexed: 05/19/2023]
Abstract
In vivo surface imaging of fluorescently labeled vasculature has become a widely used tool for functional brain imaging studies. Techniques such as phosphorescence quenching for oxygen tension measurements and indocyanine green fluorescence for vessel perfusion monitoring rely on surface measurements of vascular fluorescence. However, the depth dependence of the measured fluorescence signals has not been modeled in great detail. In this paper, we investigate the depth dependence of the measured signals using a three-dimensional Monte Carlo model combined with high resolution vascular anatomy. We found that a bulk-vascularization assumption to modeling the depth dependence of the signal does not provide an accurate picture of penetration depth of the collected fluorescence signal in most cases. Instead the physical distribution of microvasculature, the degree of absorption difference between extravascular and intravascular space, and the overall difference in absorption at the excitation and emission wavelengths must be taken into account to determine the depth penetration of the fluorescence signal. Additionally, we found that using targeted illumination can provide for superior surface vessel sensitivity over wide-field illumination, with small area detection offering an even greater amount of sensitivity to surface vasculature. Depth sensitivity can be enhanced by either increasing the detector area or increasing the illumination area. Finally, we see that excitation wavelength and vessel size can affect intra-vessel sampling distribution, as well as the amount of signal that originates from inside the vessel under targeted illumination conditions.
Collapse
Affiliation(s)
- Mitchell A. Davis
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712,
USA
| | - S. M. Shams Kazmi
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712,
USA
| | - Adrien Ponticorvo
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712,
USA
| | - Andrew K. Dunn
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712,
USA
| |
Collapse
|
78
|
Abstract
Nonlinear phase dispersion spectroscopy is introduced as a means to retrieve wideband, high spectral resolution profiles of the wavelength-dependent real part of the refractive index. The method is based on detecting dispersion effects imparted to a light field with low coherence transmitted through a thin sample and detected interferometrically in the spectral domain. The same sampled signal is also processed to yield quantitative phase maps and spectral information regarding the total attenuation coefficient using spectral-domain phase microscopy and spectroscopic optical coherence tomography (SOCT), respectively. Proof-of-concept experiments using fluorescent and nonfluorescent polystyrene beads and another using a red blood cell demonstrate the ability of the method to quantify various absorptive/dispersive features. The increased sensitivity of this method, novel to our knowledge, is compared to intensity-based spectroscopy (e.g., SOCT), and potential applications are discussed.
Collapse
Affiliation(s)
- Francisco E Robles
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA.
| | | | | |
Collapse
|
79
|
Robles FE, Wilson C, Grant G, Wax A. Molecular imaging true-colour spectroscopic optical coherence tomography. NATURE PHOTONICS 2011; 5:744-747. [PMID: 23144652 PMCID: PMC3491993 DOI: 10.1038/nphoton.2011.257] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Molecular imaging holds a pivotal role in medicine due to its ability to provide invaluable insight into disease mechanisms at molecular and cellular levels. To this end, various techniques have been developed for molecular imaging, each with its own advantages and disadvantages(1-4). For example, fluorescence imaging achieves micrometre-scale resolution, but has low penetration depths and is mostly limited to exogenous agents. Here, we demonstrate molecular imaging of endogenous and exogenous chromophores using a novel form of spectroscopic optical coherence tomography. Our approach consists of using a wide spectral bandwidth laser source centred in the visible spectrum, thereby allowing facile assessment of haemoglobin oxygen levels, providing contrast from readily available absorbers, and enabling true-colour representation of samples. This approach provides high spectral fidelity while imaging at the micrometre scale in three dimensions. Molecular imaging true-colour spectroscopic optical coherence tomography (METRiCS OCT) has significant implications for many biomedical applications including ophthalmology, early cancer detection, and understanding fundamental disease mechanisms such as hypoxia and angiogenesis.
Collapse
Affiliation(s)
- Francisco E. Robles
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, USA
- Medical Physics Program, Duke University, Durham, North Carolina 27708, USA
| | - Christy Wilson
- Pediatric Neurosurgery, Duke University, Durham, North Carolina 27708, USA
| | - Gerald Grant
- Pediatric Neurosurgery, Duke University, Durham, North Carolina 27708, USA
| | - Adam Wax
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, USA
- Medical Physics Program, Duke University, Durham, North Carolina 27708, USA
- Correspondence and requests for materials should be addressed to A.W.
| |
Collapse
|
80
|
Kuranov RV, Kazmi S, McElroy AB, Kiel JW, Dunn AK, Milner TE, Duong TQ. In vivo depth-resolved oxygen saturation by Dual-Wavelength Photothermal (DWP) OCT. OPTICS EXPRESS 2011; 19:23831-44. [PMID: 22109408 PMCID: PMC3482904 DOI: 10.1364/oe.19.023831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Microvasculature hemoglobin oxygen saturation (SaO2) is important in the progression of various pathologies. Non-invasive depth-resolved measurement of SaO2 levels in tissue microvasculature has the potential to provide early biomarkers and a better understanding of the pathophysiological processes allowing improved diagnostics and prediction of disease progression. We report proof-of-concept in vivo depth-resolved measurement of SaO(2) levels in selected 30 µm diameter arterioles in the murine brain using Dual-Wavelength Photothermal (DWP) Optical Coherence Tomography (OCT) with 800 nm and 770 nm photothermal excitation wavelengths. Depth location of back-reflected light from a target arteriole was confirmed using Doppler and speckle contrast OCT images. SaO(2) measured in a murine arteriole with DWP-OCT is linearly correlated (R(2)=0.98) with systemic SaO(2) values recorded by a pulse-oximeter. DWP-OCT are steadily lower (10.1%) than systemic SaO(2) values except during pure oxygen breathing. DWP-OCT is insensitive to OCT intensity variations and is a candidate approach for in vivo depth-resolved quantitative imaging of microvascular SaO(2) levels.
Collapse
Affiliation(s)
- Roman V Kuranov
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA.
| | | | | | | | | | | | | |
Collapse
|
81
|
Liu X, Zhang K, Huang Y, Kang JU. Spectroscopic-speckle variance OCT for microvasculature detection and analysis. BIOMEDICAL OPTICS EXPRESS 2011; 2:2995-3009. [PMID: 22076262 PMCID: PMC3207370 DOI: 10.1364/boe.2.002995] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/29/2011] [Accepted: 10/02/2011] [Indexed: 05/20/2023]
Abstract
We propose and studied optical coherence tomography (OCT) combining spectroscopic (SOCT) and speckle variance (svOCT) functions to effectively detect locations of microvasculatures and assess blood oxygen saturation level. Chorioallantoic membrane of a chick embryo was imaged in vivo to perform the analysis of the system. We also studied the effect of speckle in spectral domain using experimental data and performed time-averaging to reduce speckle noise locally. We combined SOCT and svOCT images using hue, saturation and value (HSV) color map to show the localized spectroscopic property of blood. Results show distinct spectroscopic properties between arterial blood and capillary blood.
Collapse
|
82
|
Bosschaart N, Faber DJ, van Leeuwen TG, Aalders MCG. In vivo low-coherence spectroscopic measurements of local hemoglobin absorption spectra in human skin. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:100504. [PMID: 22029343 DOI: 10.1117/1.3644497] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Localized spectroscopic measurements of optical properties are invaluable for diagnostic applications that involve layered tissue structures, but conventional spectroscopic techniques lack exact control over the size and depth of the probed tissue volume. We show that low-coherence spectroscopy (LCS) overcomes these limitations by measuring local attenuation and absorption coefficient spectra in layered phantoms. In addition, we demonstrate the first in vivo LCS measurements of the human epidermis and dermis only. From the measured absorption in two distinct regions of the dermal microcirculation, we determine total hemoglobin concentration (3.0±0.5 g∕l and 7.8±1.2 g∕l) and oxygen saturation.
Collapse
Affiliation(s)
- Nienke Bosschaart
- University of Amsterdam, Academic Medical Center, Department of Biomedical Engineering and Physics, P.O. Box 22700, NL-1100 DE Amsterdam, The Netherlands.
| | | | | | | |
Collapse
|
83
|
Gambichler T, Jaedicke V, Terras S. Optical coherence tomography in dermatology: technical and clinical aspects. Arch Dermatol Res 2011; 303:457-73. [DOI: 10.1007/s00403-011-1152-x] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Revised: 05/04/2011] [Accepted: 05/19/2011] [Indexed: 11/24/2022]
|
84
|
Kuranov RV, Qiu J, McElroy AB, Estrada A, Salvaggio A, Kiel J, Dunn AK, Duong TQ, Milner TE. Depth-resolved blood oxygen saturation measurement by dual-wavelength photothermal (DWP) optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2011; 2:491-504. [PMID: 21412455 PMCID: PMC3047355 DOI: 10.1364/boe.2.000491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 01/24/2011] [Accepted: 01/29/2011] [Indexed: 05/03/2023]
Abstract
Non-invasive depth-resolved measurement of hemoglobin oxygen saturation (SaO(2)) levels in discrete blood vessels may have implications for diagnosis and treatment of various pathologies. We introduce a novel Dual-Wavelength Photothermal (DWP) Optical Coherence Tomography (OCT) for non-invasive depth-resolved measurement of SaO(2) levels in a blood vessel phantom. DWP OCT SaO(2) is linearly correlated with blood-gas SaO(2) measurements. We demonstrate 6.3% precision in SaO(2) levels measured a phantom blood vessel using DWP-OCT with 800 and 765 nm excitation wavelengths. Sources of uncertainty in SaO(2) levels measured with DWP-OCT are identified and characterized.
Collapse
Affiliation(s)
- Roman V. Kuranov
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Jinze Qiu
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Austin B. McElroy
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Arnold Estrada
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Anthony Salvaggio
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Jeffrey Kiel
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Andrew K. Dunn
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Timothy Q. Duong
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
- South Texas Veterans Health Care System, San Antonio, Texas 78229, USA
| | - Thomas E. Milner
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| |
Collapse
|