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Kunala K, Tang JAH, Parkins K, Hunter JJ. Multispectral label-free in vivo cellular imaging of human retinal pigment epithelium using adaptive optics fluorescence lifetime ophthalmoscopy improves feasibility for low emission analysis and increases sensitivity for detecting changes with age and eccentricity. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:S22707. [PMID: 38962492 PMCID: PMC11221116 DOI: 10.1117/1.jbo.29.s2.s22707] [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: 10/15/2023] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 07/05/2024]
Abstract
Significance Adaptive optics fluorescence lifetime ophthalmoscopy (AOFLIO) provides a label-free approach to observe functional and molecular changes at cellular scale in vivo. Adding multispectral capabilities improves interpretation of lifetime fluctuations due to individual fluorophores in the retinal pigment epithelium (RPE). Aim To quantify the cellular-scale changes in autofluorescence with age and eccentricity due to variations in lipofuscin, melanin, and melanolipofuscin in RPE using multispectral AOFLIO. Approach AOFLIO was performed on six subjects at seven eccentricities. Four imaging channels (λ ex / λ em ) were used: 473/SSC, 473/LSC, 532/LSC, and 765/NIR. Cells were segmented and the timing signals of each pixel in a cell were combined into a single histogram, which were then used to compute the lifetime and phasor parameters. An ANOVA was performed to investigate eccentricity and spectral effects on each parameter. Results A repeatability analysis revealed < 11.8 % change in lifetime parameters in repeat visits for 532/LSC. The 765/NIR and 532/LSC had eccentricity and age effects similar to previous reports. The 473/LSC had a change in eccentricity with mean lifetime and a phasor component. Both the 473/LSC and 473/SSC had changes in eccentricity in the short lifetime component and its relative contribution. The 473/SSC had no trend in eccentricity in phasor. The comparison across the four channels showed differences in lifetime and phasor parameters. Conclusions Multispectral AOFLIO can provide a more comprehensive picture of changes with age and eccentricity. These results indicate that cell segmentation has the potential to allow investigations in low-photon scenarios such as in older or diseased subjects with the co-capture of an NIR channel (such as 765/NIR) with the desired spectral channel. This work represents the first multispectral, cellular-scale fluorescence lifetime comparison in vivo in the human RPE and may be a useful method for tracking diseases.
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Affiliation(s)
- Karteek Kunala
- Stanford University, Byers Eye Institute, Palo Alto, California, United States
| | - Janet A. H. Tang
- University of Rochester, Center for Visual Science, Rochester, New York, United States
- University of Rochester, The Institute of Optics, Rochester, New York, United States
| | - Keith Parkins
- University of Rochester, Center for Visual Science, Rochester, New York, United States
| | - Jennifer J. Hunter
- University of Rochester, Center for Visual Science, Rochester, New York, United States
- University of Rochester, The Institute of Optics, Rochester, New York, United States
- University of Waterloo, School of Optometry and Vision Science, Waterloo, Ontario, Canada
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2
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Remala A, Reddy KK, Velagapudi P. Advances in Intravascular Ultrasound. INDIAN JOURNAL OF CARDIOVASCULAR DISEASE IN WOMEN 2023. [DOI: 10.25259/ijcdw_2_2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Since its inception, intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have played a significant role in evaluating the pathophysiology of coronary artery disease (CAD) guiding the interventional and medical management of CAD improving outcomes in patients. Although the benefits of each of these modalities have been proven, due to some limitations, no single intravascular imaging technique has been proven to provide a detailed and complete evaluation of all CAD lesions. The use of different intravascular imaging modalities sequentially may lead to complications, which are cumbersome, consume time, and add financial burden to the patient. Recently, hybrid imaging catheters that combine OCT and IVUS benefits have been developed to limit these problems. Intravascular imaging techniques we are using currently have some drawbacks that hinder accurate assessment of plaque morphology and pathobiology as demonstrated in many histological studies, causing difficulty in identifying high-risk plaques. To overcome these limitations, great efforts have been put into developing hybrid, dual-probe catheters by combining imaging modalities to get an accurate analysis of plaque characteristics, and high-risk lesions. At present, many dual-probe catheters are available including combined IVUS-OCT, near-infrared spectroscopy-IVUS that is available commercially, the OCT-near infrared fluorescence (NIRF) molecular imaging, IVUS-NIRF, and combined fluorescence lifetime-IVUS imaging. Application of this combined multimodal imaging in clinical practice overcomes the limitations of standalone imaging and helps in providing a comprehensive and accurate visualization of plaque characteristics, composition, and plaque biology. The present article summarizes the advances in hybrid intravascular imaging, analyses the technical hindrances that should be known to have a use in the different clinical circumstances, and the till date shreds of evidence available from their first clinical application aiming to bring these modalities into the limelight and their potential role in the study of CAD.
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Li C, Bec J, Zhou X, Marcu L. Dual-modality fluorescence lifetime imaging-optical coherence tomography intravascular catheter system with freeform catheter optics. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:076005. [PMID: 35864574 PMCID: PMC9300477 DOI: 10.1117/1.jbo.27.7.076005] [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: 05/17/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Intravascular imaging is key to investigations into atherosclerotic plaque pathobiology and cardiovascular diagnostics overall. The development of multimodal imaging devices compatible with intracoronary applications has the potential to address limitations of currently available single-modality systems. AIM We designed and characterized a robust, high performance multimodal imaging system that combines optical coherence tomography (OCT) and multispectral fluorescence lifetime imaging (FLIm) for intraluminal simultaneous assessment of structural and biochemical properties of coronary arteries. APPROACH Several shortcomings of existing FLIm-OCT catheter systems are addressed by adopting key features, namely (1) a custom fiber optic rotary joint based on an air bearing, (2) a broadband catheter using a freeform reflective optics, and (3) integrated solid-state FLIm detectors. Improvements are quantified using a combination of experimental characterization and simulations. RESULTS Excellent UV and IR coupling efficiencies and stability (IR: 75.7 % ± 0.4 % , UV: 45.7 % ± 0.35 % ) are achieved; high FLIm optical performance is obtained (UV beam FWHM: 50 μm) contemporaneously with excellent OCT beam quality (IR beam FWHM: 17 μm). High-quality FLIm OCT image of a human coronary artery specimen was acquired. CONCLUSION The ability of this intravascular imaging system to provide comprehensive structural and biochemical properties will be valuable to further our understanding of plaque pathophysiology and improve cardiovascular diagnostics.
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Affiliation(s)
- Cai Li
- University of California, Department of Biomedical Engineering, Davis, California, United States
| | - Julien Bec
- University of California, Department of Biomedical Engineering, Davis, California, United States
| | - Xiangnan Zhou
- University of California, Department of Biomedical Engineering, Davis, California, United States
| | - Laura Marcu
- University of California, Department of Biomedical Engineering, Davis, California, United States
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Alfonso-Garcia A, Bec J, Weyers B, Marsden M, Zhou X, Li C, Marcu L. Mesoscopic fluorescence lifetime imaging: Fundamental principles, clinical applications and future directions. JOURNAL OF BIOPHOTONICS 2021; 14:e202000472. [PMID: 33710785 PMCID: PMC8579869 DOI: 10.1002/jbio.202000472] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 05/16/2023]
Abstract
Fluorescence lifetime imaging (FLIm) is an optical spectroscopic imaging technique capable of real-time assessments of tissue properties in clinical settings. Label-free FLIm is sensitive to changes in tissue structure and biochemistry resulting from pathological conditions, thus providing optical contrast to identify and monitor the progression of disease. Technical and methodological advances over the last two decades have enabled the development of FLIm instrumentation for real-time, in situ, mesoscopic imaging compatible with standard clinical workflows. Herein, we review the fundamental working principles of mesoscopic FLIm, discuss the technical characteristics of current clinical FLIm instrumentation, highlight the most commonly used analytical methods to interpret fluorescence lifetime data and discuss the recent applications of FLIm in surgical oncology and cardiovascular diagnostics. Finally, we conclude with an outlook on the future directions of clinical FLIm.
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Affiliation(s)
- Alba Alfonso-Garcia
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Julien Bec
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Brent Weyers
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Mark Marsden
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Xiangnan Zhou
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Cai Li
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, Davis, California
- Department Neurological Surgery, University of California, Davis, California
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5
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Peng C, Wu H, Kim S, Dai X, Jiang X. Recent Advances in Transducers for Intravascular Ultrasound (IVUS) Imaging. SENSORS (BASEL, SWITZERLAND) 2021; 21:3540. [PMID: 34069613 PMCID: PMC8160965 DOI: 10.3390/s21103540] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/11/2021] [Accepted: 05/17/2021] [Indexed: 12/16/2022]
Abstract
As a well-known medical imaging methodology, intravascular ultrasound (IVUS) imaging plays a critical role in diagnosis, treatment guidance and post-treatment assessment of coronary artery diseases. By cannulating a miniature ultrasound transducer mounted catheter into an artery, the vessel lumen opening, vessel wall morphology and other associated blood and vessel properties can be precisely assessed in IVUS imaging. Ultrasound transducer, as the key component of an IVUS system, is critical in determining the IVUS imaging performance. In recent years, a wide range of achievements in ultrasound transducers have been reported for IVUS imaging applications. Herein, a comprehensive review is given on recent advances in ultrasound transducers for IVUS imaging. Firstly, a fundamental understanding of IVUS imaging principle, evaluation parameters and IVUS catheter are summarized. Secondly, three different types of ultrasound transducers (piezoelectric ultrasound transducer, piezoelectric micromachined ultrasound transducer and capacitive micromachined ultrasound transducer) for IVUS imaging are presented. Particularly, the recent advances in piezoelectric ultrasound transducer for IVUS imaging are extensively examined according to their different working mechanisms, configurations and materials adopted. Thirdly, IVUS-based multimodality intravascular imaging of atherosclerotic plaque is discussed. Finally, summary and perspectives on the future studies are highlighted for IVUS imaging applications.
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Affiliation(s)
- Chang Peng
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.P.); (H.W.)
| | - Huaiyu Wu
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.P.); (H.W.)
| | | | - Xuming Dai
- Department of Cardiology, New York-Presbyterian Queens Hospital, Flushing, NY 11355, USA;
| | - Xiaoning Jiang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.P.); (H.W.)
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Jin H, Zheng Z, Liu S, Zheng Y. Evaluation of Reconstruction Methodology for Helical Scan Guided Photoacoustic Endoscopy. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:4198-4208. [PMID: 32755852 DOI: 10.1109/tmi.2020.3014410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photoacoustic endoscopy (PAE), combining both advantages of optical contrast and acoustic resolution, can visualize the chemical-specific optical information of tissues inside human-body. Recently, its corresponding reconstruction methods have been extensively researched. However, most of them are limited on cylindrical scan trajectories, rather than a helical scan which is more clinically practical. On this note, this article proposes a methodology of imaging reconstruction and evaluation for helical scan guided PAE. Different from traditional reconstruction method, synthetic aperture focusing technique (SAFT), our method reconstructs image using wavefield extrapolation which significantly improves computational efficiency and even takes only 0.25 seconds for 3-D reconstructions. In addition, the proposed evaluation methodology can estimate the resolutions and deviations of reconstructed images in advance, and then can be used to optimize the PAE scan parameters. Groups of simulations as well as ex-vivo experiments with different scan parameters are provided to fully demonstrate the performance of the proposed techniques. The quantitatively measured angular resolutions and deviations agree well with our theoretical derivation results D√{rs2 +h2} / [1.25(rs rd +h2)] (rad) and -h l / (rs rd +h2) (rad), respectively D,rd, rs,h and l represent transducer diameter, radius of scan trajectory, radius of source position, unit helical pitch and the distance from targets to helical scan plane, respectively). This theoretical result also suits for circular and cylindrical scan in case of h = 0 .
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7
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Vazquez-Portalatin N, Alfonso-Garcia A, Liu JC, Marcu L, Panitch A. Physical, Biomechanical, and Optical Characterization of Collagen and Elastin Blend Hydrogels. Ann Biomed Eng 2020; 48:2924-2935. [PMID: 32929559 DOI: 10.1007/s10439-020-02605-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/02/2020] [Indexed: 12/13/2022]
Abstract
Collagen and elastin proteins are major components of the extracellular matrix of many organs. The presence of collagen and elastin networks, and their associated properties, in different tissues have led scientists to study collagen and elastin composites for use in tissue engineering. In this study, we characterized physical, biochemical, and optical properties of gels composed of collagen and elastin blends. We demonstrated that the addition of varying amounts of elastin to the constructs alters collagen fibrillogenesis, D-banding pattern length, and storage modulus. However, the addition of elastin does not affect collagen fibril diameter. We also evaluated the autofluorescence properties of the different collagen and elastin blends with fluorescence lifetime imaging (FLIm). Autofluorescence emission showed a red shift with the addition of elastin to the hydrogels. The fluorescence lifetime values of the gels increased with the addition of elastin and were strongly correlated with the storage moduli measurements. These results suggest that FLIm can be used to monitor the gels' mechanical properties nondestructively. These collagen and elastin constructs, along with the FLIm capabilities, can be used to develop and study collagen and elastin composites for tissue engineering and regenerative medicine.
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Affiliation(s)
- Nelda Vazquez-Portalatin
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA.,Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA
| | - Alba Alfonso-Garcia
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA
| | - Julie C Liu
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA.,Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Dr, West Lafayette, IN, 47907, USA
| | - Laura Marcu
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA
| | - Alyssa Panitch
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA. .,Department of Surgery, University of California, Davis, 2335 Stockton Boulevard, Sacramento, CA, 95817, USA.
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8
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Current Advances in the Diagnostic Imaging of Atherosclerosis: Insights into the Pathophysiology of Vulnerable Plaque. Int J Mol Sci 2020; 21:ijms21082992. [PMID: 32340284 PMCID: PMC7216001 DOI: 10.3390/ijms21082992] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/02/2020] [Accepted: 04/15/2020] [Indexed: 12/13/2022] Open
Abstract
Atherosclerosis is a lipoprotein-driven inflammatory disorder leading to a plaque formation at specific sites of the arterial tree. After decades of slow progression, atherosclerotic plaque rupture and formation of thrombi are the major factors responsible for the development of acute coronary syndromes (ACSs). In this regard, the detection of high-risk (vulnerable) plaques is an ultimate goal in the management of atherosclerosis and cardiovascular diseases (CVDs). Vulnerable plaques have specific morphological features that make their detection possible, hence allowing for identification of high-risk patients and the tailoring of therapy. Plaque ruptures predominantly occur amongst lesions characterized as thin-cap fibroatheromas (TCFA). Plaques without a rupture, such as plaque erosions, are also thrombi-forming lesions on the most frequent pathological intimal thickening or fibroatheromas. Many attempts to comprehensively identify vulnerable plaque constituents with different invasive and non-invasive imaging technologies have been made. In this review, advantages and limitations of invasive and non-invasive imaging modalities currently available for the identification of plaque components and morphologic features associated with plaque vulnerability, as well as their clinical diagnostic and prognostic value, were discussed.
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9
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Bec J, Li C, Marcu L. Broadband, freeform focusing micro-optics for a side-viewing imaging catheter. OPTICS LETTERS 2019; 44:4961-4964. [PMID: 31613239 PMCID: PMC9010228 DOI: 10.1364/ol.44.004961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 08/30/2019] [Indexed: 05/28/2023]
Abstract
Successful implementation of a catheter-based imaging system relies on the integration of high-performance miniaturized distal end optics. Typically, compensation of chromatic dispersion, as well as astigmatism introduced by the device's sheath, can be addressed only by combining multiple optical elements, adversely impacting size and manufacturability. Here, we present a 300×300×800 μm3 monolithic optic that provides high optical performances over an extended wavelength range (near UV-visible-IR) with minimal chromatic aberrations. The design of the optic, fully optimized using standard optical simulation tools, provides the ability to freely determine aperture and working distance. Manufacturing is cost effective and suited for prototyping and production alike. The experimental characterization of the optic demonstrates a good match with simulation results and performances well suited to both optical coherence tomography and fluorescence imaging, thus paving the way for high-performance multimodal endoscopy systems.
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Affiliation(s)
- Julien Bec
- Department of Biomedical Engineering, University of California, Davis, California 95616, USA
- Institute of Physical Chemistry and Abbe Center of Photonics (IPC), Friedrich-Schiller-University, D-07743 Jena, Germany
- Leibniz Institute of Photonic Technology, D-07745 Jena, Germany
| | - Cai Li
- Department of Biomedical Engineering, University of California, Davis, California 95616, USA
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, California 95616, USA
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10
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Li C, Alfonso-Garcia A, McMasters J, Bec J, Weyers B, Uyesaka L, Griffiths L, Panitch A, Marcu L. Simultaneous intraluminal imaging of tissue autofluorescence and eGFP-labeled cells in engineered vascular grafts inside a bioreactor. Methods Appl Fluoresc 2019; 7:044003. [PMID: 31505471 DOI: 10.1088/2050-6120/ab4342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The growing demand for tissue engineered vascular grafts (TEVG) motivates the development of optimized fabrication and monitoring procedures. Bioreactors which provide physiologically-relevant conditions are important for improving holistic TEVG properties and performance. Herein we describe a fiber-based intraluminal imaging system that allows for in situ assessment of vascular materials and re-cellularization processes inside a bioreactor by simultaneous and co-registered measurements of endogenous fluorescence lifetime and exogenous marker fluorescence intensity. The lumen of 6 vascular grafts (∼4 mm diameter) were scanned by reciprocally rotating a 41° angle polished multimode optical fiber inside a protective glass tube with outer diameter of 3 mm. Tubular bovine pericardium constructs were recellularized using enhanced Green Fluorescent Protein (eGFP) transfected cells in a custom bioreactor. The imaging system has resolved consistently the cellular autofluorescence from that of tissue matrix in situ based on the lifetime fluorescence properties of endogenous molecular species. The location of the re-cellularized area was validated by the eGFP emission. Current results demonstrate the potential of this system as a valuable tool in tissue engineering for in situ studies of cell-tissue interactions in cylindrical or other 3-dimensional structures.
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Affiliation(s)
- Cai Li
- Department of Material Science and Engineering, University of California, Davis, United States of America
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11
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Comprehensive intravascular imaging of atherosclerotic plaque in vivo using optical coherence tomography and fluorescence lifetime imaging. Sci Rep 2018; 8:14561. [PMID: 30267024 PMCID: PMC6162321 DOI: 10.1038/s41598-018-32951-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/18/2018] [Indexed: 02/08/2023] Open
Abstract
Comprehensive imaging of both the structural and biochemical characteristics of atherosclerotic plaque is essential for the diagnosis and study of coronary artery disease because both a plaque's morphology and its biochemical composition affect the level of risk it poses. Optical coherence tomography (OCT) and fluorescence lifetime imaging (FLIm) are promising optical imaging methods for characterizing coronary artery plaques morphologically and biochemically, respectively. In this study, we present a hybrid intravascular imaging device, including a custom-built OCT/FLIm system, a hybrid optical rotary joint, and an imaging catheter, to visualize the structure and biochemical composition of the plaque in an atherosclerotic rabbit artery in vivo. Especially, the autofluorescence lifetime of the endogenous tissue molecules can be used to characterize the biochemical composition; thus no exogenous contrast agent is required. Also, the physical properties of the imaging catheter and the imaging procedures are similar to those already used clinically, facilitating rapid translation into clinical use. This new intravascular imaging catheter can open up new opportunities for clinicians and researchers to investigate and diagnose coronary artery disease by simultaneously providing tissue microstructure and biochemical composition data in vivo without the use of exogenous contrast agent.
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Alfonso-Garcia A, Shklover J, Sherlock BE, Panitch A, Griffiths LG, Marcu L. Fiber-based fluorescence lifetime imaging of recellularization processes on vascular tissue constructs. JOURNAL OF BIOPHOTONICS 2018; 11:e201700391. [PMID: 29781171 PMCID: PMC7700018 DOI: 10.1002/jbio.201700391] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/16/2018] [Indexed: 05/22/2023]
Abstract
New techniques able to monitor the maturation of tissue engineered constructs over time are needed for a more efficient control of developmental parameters. Here, a label-free fluorescence lifetime imaging (FLIm) approach implemented through a single fiber-optic interface is reported for nondestructive in situ assessment of vascular biomaterials. Recellularization processes of antigen removed bovine pericardium scaffolds with endothelial cells and mesenchymal stem cells were evaluated on the serous and the fibrous sides of the scaffolds, 2 distinct extracellular matrix niches, over the course of a 7 day culture period. Results indicated that fluorescence lifetime successfully report cell presence resolved from extracellular matrix fluorescence. The recellularization process was more rapid on the serous side than on the fibrous side for both cell types, and endothelial cells expanded faster than mesenchymal stem cells on antigen-removed bovine pericardium. Fiber-based FLIm has the potential to become a nondestructive tool for the assessment of tissue maturation by allowing in situ imaging of intraluminal vascular biomaterials.
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Affiliation(s)
- Alba Alfonso-Garcia
- Department of Biomedical Engineering, University of California Davis, Davis, California
| | - Jeny Shklover
- Department of Biomedical Engineering, University of California Davis, Davis, California
| | - Benjamin E. Sherlock
- Department of Biomedical Engineering, University of California Davis, Davis, California
| | - Alyssa Panitch
- Department of Biomedical Engineering, University of California Davis, Davis, California
| | - Leigh G. Griffiths
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
| | - Laura Marcu
- Department of Biomedical Engineering, University of California Davis, Davis, California
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Alfonso-Garcia A, Haudenschild AK, Marcu L. Label-free assessment of carotid artery biochemical composition using fiber-based fluorescence lifetime imaging. BIOMEDICAL OPTICS EXPRESS 2018; 9:4064-4076. [PMID: 30615748 PMCID: PMC6157793 DOI: 10.1364/boe.9.004064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 07/11/2018] [Accepted: 07/12/2018] [Indexed: 05/08/2023]
Abstract
Novel diagnostic tools with the ability to monitor variations in biochemical composition and provide benchmark indicators of vascular tissue maturation are needed to create functional tissue replacements. We investigated the ability of fiber-based, label-free multispectral fluorescent lifetime imaging (FLIm) to quantify the anatomical variations in biochemical composition of native carotid arteries and validated these results against biochemical assays. FLIm-derived parameters in spectral band 415-455 nm correlated with tissue collagen content (R2 = 0.64) and cell number (R2 = 0.61) and in spectral band 465-553 nm strongly correlated with elastin content (R2 = 0.89). These results suggest that FLIm holds great potential for assessing vascular tissue maturation and functional properties based on tissue autofluorescence.
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Affiliation(s)
- Alba Alfonso-Garcia
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, CA 95616,
USA
- Authors contributed equally to this work
| | - Anne K. Haudenschild
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, CA 95616,
USA
- Authors contributed equally to this work
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, CA 95616,
USA
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Nam HS, Kang WJ, Lee MW, Song JW, Kim JW, Oh WY, Yoo H. Multispectral analog-mean-delay fluorescence lifetime imaging combined with optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2018; 9:1930-1947. [PMID: 29675330 PMCID: PMC5905935 DOI: 10.1364/boe.9.001930] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/15/2018] [Accepted: 03/18/2018] [Indexed: 05/19/2023]
Abstract
The pathophysiological progression of chronic diseases, including atherosclerosis and cancer, is closely related to compositional changes in biological tissues containing endogenous fluorophores such as collagen, elastin, and NADH, which exhibit strong autofluorescence under ultraviolet excitation. Fluorescence lifetime imaging (FLIm) provides robust detection of the compositional changes by measuring fluorescence lifetime, which is an inherent property of a fluorophore. In this paper, we present a dual-modality system combining a multispectral analog-mean-delay (AMD) FLIm and a high-speed swept-source optical coherence tomography (OCT) to simultaneously visualize the cross-sectional morphology and biochemical compositional information of a biological tissue. Experiments using standard fluorescent solutions showed that the fluorescence lifetime could be measured with a precision of less than 40 psec using the multispectral AMD-FLIm without averaging. In addition, we performed ex vivo imaging on rabbit iliac normal-looking and atherosclerotic specimens to demonstrate the feasibility of the combined FLIm-OCT system for atherosclerosis imaging. We expect that the combined FLIm-OCT will be a promising next-generation imaging technique for diagnosing atherosclerosis and cancer due to the advantages of the proposed label-free high-precision multispectral lifetime measurement.
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Affiliation(s)
- Hyeong Soo Nam
- Department of Biomedical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04673, South Korea
- Equally contributed to this study
| | - Woo Jae Kang
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Gwahang-no, Yuseong-gu, Daejeon 34141, South Korea
- Equally contributed to this study
| | - Min Woo Lee
- Department of Biomedical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04673, South Korea
| | - Joon Woo Song
- Cardiovascular Center, Korea University Guro Hospital, 148 Gurodong-ro, Guro-gu, Seoul 08308, South Korea
| | - Jin Won Kim
- Cardiovascular Center, Korea University Guro Hospital, 148 Gurodong-ro, Guro-gu, Seoul 08308, South Korea
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Gwahang-no, Yuseong-gu, Daejeon 34141, South Korea
| | - Hongki Yoo
- Department of Biomedical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04673, South Korea
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Katagiri Y, Tenekecioglu E, Serruys PW, Collet C, Katsikis A, Asano T, Miyazaki Y, Piek JJ, Wykrzykowska JJ, Bourantas C, Onuma Y. What does the future hold for novel intravascular imaging devices: a focus on morphological and physiological assessment of plaque. Expert Rev Med Devices 2017; 14:985-999. [DOI: 10.1080/17434440.2017.1407646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Yuki Katagiri
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | - Carlos Collet
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Athanasios Katsikis
- Department of Cardiology, General Military Hospital of Athens, Athens, Greece
| | - Taku Asano
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Yosuke Miyazaki
- ThoraxCenter, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jan J Piek
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Christos Bourantas
- Barts Heart Centre, Barts Health NHS Trust, London, UK
- Institute of Cardiovascular Sciences, University College London, London, UK
| | - Yoshinobu Onuma
- ThoraxCenter, Erasmus Medical Center, Rotterdam, The Netherlands
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16
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SHERLOCK BENJAMINE, PHIPPS JENNIFERE, BEC JULIEN, MARCU LAURA. Simultaneous, label-free, multispectral fluorescence lifetime imaging and optical coherence tomography using a double-clad fiber. OPTICS LETTERS 2017; 42:3753-3756. [PMID: 28957119 PMCID: PMC8951707 DOI: 10.1364/ol.42.003753] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We present a novel fiber-based imaging platform that allows simultaneous fluorescence lifetime imaging (FLIm) and optical coherence tomography (OCT) using a double-clad fiber. This platform acquires co-registered images showing structural and compositional contrast in unlabeled biological samples by scanning the fiber tip across the sample surface. In this Letter, we report a characterization of each modality and show examples of co-registered FLIm and OCT images acquired from a lemon segment and a section of human coronary artery. The close comparison between the combined FLIm and OCT images and a co-registered histology section provides a qualitative validation of the technique and highlights its potential for minimally invasive, multimodal imaging of tissue structure and composition.
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17
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Bec J, Phipps JE, Gorpas D, Ma D, Fatakdawala H, Margulies KB, Southard JA, Marcu L. In vivo label-free structural and biochemical imaging of coronary arteries using an integrated ultrasound and multispectral fluorescence lifetime catheter system. Sci Rep 2017; 7:8960. [PMID: 28827758 PMCID: PMC5566546 DOI: 10.1038/s41598-017-08056-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 07/03/2017] [Indexed: 11/09/2022] Open
Abstract
Existing clinical intravascular imaging modalities are not capable of accurate detection of critical plaque pathophysiology in the coronary arteries. This study reports the first intravascular catheter combining intravascular ultrasound (IVUS) with multispectral fluorescence lifetime imaging (FLIm) that enables label-free simultaneous assessment of morphological and biochemical features of coronary vessels in vivo. A 3.7 Fr catheter with a fiber-optic channel was constructed based on a 40 MHz clinical IVUS catheter. The ability to safely acquire co-registered FLIm-IVUS data in vivo using Dextran40 solution flushing was demonstrated in swine coronary arteries. FLIm parameters from the arterial wall were consistent with the emission of fluorophores present in healthy arterial wall (collagen, elastin). Additionally, structural and biochemical features from atherosclerotic lesions were acquired in ex vivo human coronary samples and corroborated with histological findings. Current results show that FLIm parameters linked to the amount of structural proteins (e.g. collagen, elastin) and lipids (e.g. foam cells, extracellular lipids) in the first 200 μm of the intima provide important biochemical information that can supplement IVUS data for a comprehensive assessment of plaques pathophysiology. The unique FLIm-IVUS system evaluated here has the potential to provide a comprehensive insight into atherosclerotic lesion formation, diagnostics and response to therapy.
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Affiliation(s)
- Julien Bec
- Department of Biomedical Engineering, University of California Davis, Davis, 95616, CA, USA
| | - Jennifer E Phipps
- Department of Biomedical Engineering, University of California Davis, Davis, 95616, CA, USA
| | - Dimitris Gorpas
- Department of Biomedical Engineering, University of California Davis, Davis, 95616, CA, USA.,Institute of Biological and Medical Imaging, Helmholtz Zentrum, München, Germany
| | - Dinglong Ma
- Department of Biomedical Engineering, University of California Davis, Davis, 95616, CA, USA
| | - Hussain Fatakdawala
- Department of Biomedical Engineering, University of California Davis, Davis, 95616, CA, USA.,Abbott, Sylmar, CA, USA
| | - Kenneth B Margulies
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Jeffrey A Southard
- UC Davis Health System, Division of Cardiovascular Medicine, University of California Davis, Sacramento, 95817, CA, USA
| | - Laura Marcu
- Department of Biomedical Engineering, University of California Davis, Davis, 95616, CA, USA.
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18
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Bourantas CV, Jaffer FA, Gijsen FJ, van Soest G, Madden SP, Courtney BK, Fard AM, Tenekecioglu E, Zeng Y, van der Steen AF, Emelianov S, Muller J, Stone PH, Marcu L, Tearney GJ, Serruys PW. Hybrid intravascular imaging: recent advances, technical considerations, and current applications in the study of plaque pathophysiology. Eur Heart J 2017; 38:400-412. [PMID: 27118197 PMCID: PMC5837589 DOI: 10.1093/eurheartj/ehw097] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 01/31/2016] [Accepted: 02/22/2016] [Indexed: 11/14/2022] Open
Abstract
Cumulative evidence from histology-based studies demonstrate that the currently available intravascular imaging techniques have fundamental limitations that do not allow complete and detailed evaluation of plaque morphology and pathobiology, limiting the ability to accurately identify high-risk plaques. To overcome these drawbacks, new efforts are developing for data fusion methodologies and the design of hybrid, dual-probe catheters to enable accurate assessment of plaque characteristics, and reliable identification of high-risk lesions. Today several dual-probe catheters have been introduced including combined near infrared spectroscopy-intravascular ultrasound (NIRS-IVUS), that is already commercially available, IVUS-optical coherence tomography (OCT), the OCT-NIRS, the OCT-near infrared fluorescence (NIRF) molecular imaging, IVUS-NIRF, IVUS intravascular photoacoustic imaging and combined fluorescence lifetime-IVUS imaging. These multimodal approaches appear able to overcome limitations of standalone imaging and provide comprehensive visualization of plaque composition and plaque biology. The aim of this review article is to summarize the advances in hybrid intravascular imaging, discuss the technical challenges that should be addressed in order to have a use in the clinical arena, and present the evidence from their first applications aiming to highlight their potential value in the study of atherosclerosis.
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Affiliation(s)
| | - Farouc A. Jaffer
- Cardiovascular Research Center and Cardiology Division, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA
| | - Frank J. Gijsen
- Thorax Center, Erasmus MC, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | - Gijs van Soest
- Thorax Center, Erasmus MC, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | | | - Brian K. Courtney
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
| | - Ali M. Fard
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA
| | - Erhan Tenekecioglu
- Thorax Center, Erasmus MC, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | - Yaping Zeng
- Thorax Center, Erasmus MC, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | | | - Stanislav Emelianov
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA
| | | | - Peter H. Stone
- Cardiovascular Division, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, CA, USA
| | - Guillermo J. Tearney
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA
| | - Patrick W. Serruys
- Thorax Center, Erasmus MC, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
- International Centre for Cardiovascular Health, NHLI, Imperial College London, London, UK
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19
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Cosci A, Nogueira MS, Pratavieira S, Takahama A, Azevedo RDS, Kurachi C. Time-resolved fluorescence spectroscopy for clinical diagnosis of actinic cheilitis. BIOMEDICAL OPTICS EXPRESS 2016; 7:4210-4219. [PMID: 27867726 PMCID: PMC5102522 DOI: 10.1364/boe.7.004210] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 05/28/2023]
Abstract
Actinic cheilitis is a potentially malignant disorder of the lips. Its first cause is believed to be UV sun radiation. The lesion is highly heterogeneous, making the choice of area to be biopsied difficult. This study exploits the capabilities of time-resolved fluorescence spectroscopy for the identification of the most representative area to be biopsied. A preliminary study was performed on fourteen patients. A classification algorithm was used on data acquired on nine different biopsies. The algorithm discriminated between absent, mild, and moderate dysplasia with a sensitivity of 92.9%, 90.0%, and 80.0%, respectively. The false positive rate for healthy tissue (specificity) was 88.8%.
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Affiliation(s)
- Alessandro Cosci
- Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Piazza del Viminale 1, 00184 Rome, Italy; IFAC-CNR, Istituto di Fisica Applicata "Nello Carrara," Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy; São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP Brazil;
| | - Marcelo Saito Nogueira
- São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP Brazil;
| | - Sebastião Pratavieira
- São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP Brazil
| | - Ademar Takahama
- Faculdade de Odontologia de Nova Friburgo, Universidade Federal Fluminense, RJ, Brazil
| | | | - Cristina Kurachi
- São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP Brazil
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20
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Dochow S, Ma D, Latka I, Bocklitz T, Hartl B, Bec J, Fatakdawala H, Marple E, Urmey K, Wachsmann-Hogiu S, Schmitt M, Marcu L, Popp J. Combined fiber probe for fluorescence lifetime and Raman spectroscopy. Anal Bioanal Chem 2015; 407:8291-301. [PMID: 26093843 PMCID: PMC4995092 DOI: 10.1007/s00216-015-8800-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 12/23/2022]
Abstract
In this contribution we present a dual modality fiber optic probe combining fluorescence lifetime imaging (FLIm) and Raman spectroscopy for in vivo endoscopic applications. The presented multi-spectroscopy probe enables efficient excitation and collection of fluorescence lifetime signals for FLIm in the UV/visible wavelength region, as well as of Raman spectra in the near-IR for simultaneous Raman/FLIm imaging. The probe was characterized in terms of its lateral resolution and distance dependency of the Raman and FLIm signals. In addition, the feasibility of the probe for in vivo FLIm and Raman spectral characterization of tissue was demonstrated. Graphical Abstract An image comparison between FLIm and Raman spectroscopy acquired with the bimodal probe onseveral tissue samples.
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Affiliation(s)
- Sebastian Dochow
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Dinglong Ma
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Drive, Davis, CA, 95616, USA
| | - Ines Latka
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Thomas Bocklitz
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Brad Hartl
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Drive, Davis, CA, 95616, USA
| | - Julien Bec
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Drive, Davis, CA, 95616, USA
| | - Hussain Fatakdawala
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Drive, Davis, CA, 95616, USA
| | - Eric Marple
- EmVision LCC, 1471 F Road, Loxahatchee, FL, 33470, USA
| | - Kirk Urmey
- EmVision LCC, 1471 F Road, Loxahatchee, FL, 33470, USA
| | - Sebastian Wachsmann-Hogiu
- Department of Pathology and Laboratory Medicine and Center for Biophotonics, University of California, Davis, 2700 Stockton Blvd., Sacramento, CA, 95817, USA
| | - Michael Schmitt
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Drive, Davis, CA, 95616, USA.
| | - Jürgen Popp
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany.
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Str. 9, 07745, Jena, Germany.
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21
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Fatakdawala H, Gorpas D, Bishop JW, Bec J, Ma D, Southard JA, Margulies KB, Marcu L. Fluorescence Lifetime Imaging Combined with Conventional Intravascular Ultrasound for Enhanced Assessment of Atherosclerotic Plaques: an Ex Vivo Study in Human Coronary Arteries. J Cardiovasc Transl Res 2015; 8:253-63. [PMID: 25931307 PMCID: PMC4473095 DOI: 10.1007/s12265-015-9627-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 04/15/2015] [Indexed: 11/16/2022]
Abstract
This study evaluates the ability of label-free fluorescence lifetime imaging (FLIm) to complement intravascular ultrasound (IVUS) for concurrent visualization of human coronary vessel composition, structure, and pathology. Co-registered FLIm and IVUS data from 16 coronary segments were correlated to eight distinct pathological features including thin-cap fibroatheroma (TCFA). The sensitivity, specificity, and positive predictive value for combined FLIm-IVUS (89, 99, 89 %) were better than FLIm (70, 98, 88 %) and IVUS (45, 94, 62 %) alone in distinguishing between pathologies. FLIm can assess compositional changes in luminal surface through variations in fluorescence lifetime values (<3.5 ns for lipid-rich areas; >4 ns for collagen-rich areas) enabling detection of macrophages in fibrous caps (sensitivity, 86 %) and distinguishing between relatively stable thick-cap fibroatheromas and rupture-prone TCFA (sensitivity, 80 %) amongst other features. Current results demonstrate the potential of FLIm-IVUS as a new intravascular method for improved evaluation of plaques that may subsequently aid in guiding coronary intervention.
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Affiliation(s)
- Hussain Fatakdawala
- Department of Biomedical Engineering, University of California Davis, 451 E. Health Sciences Drive, Davis, CA, 95616, USA
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22
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Fatakdawala H, Griffiths LG, Humphrey S, Marcu L. Time-resolved fluorescence spectroscopy and ultrasound backscatter microscopy for nondestructive evaluation of vascular grafts. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:080503. [PMID: 25147960 PMCID: PMC4407666 DOI: 10.1117/1.jbo.19.8.080503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 07/28/2014] [Accepted: 08/01/2014] [Indexed: 06/03/2023]
Abstract
Quantitative and qualitative evaluations of structure and composition are important in monitoring development of engineered vascular tissue both in vitro and in vivo. Destructive techniques are an obstacle for performing time-lapse analyses from a single sample or animal. This study demonstrates the ability of time-resolved fluorescence spectroscopy (TRFS) and ultrasound backscatter microscopy (UBM), as nondestructive and synergistic techniques, for compositional and morphological analyses of tissue grafts, respectively. UBM images and integrated backscatter coefficients demonstrate the ability to visualize and quantify postimplantation changes in vascular graft biomaterials such as loss of the external elastic lamina and intimal/medial thickening over the grafted region as well as graft integration with the surrounding tissue. TRFS results show significant changes in spectra, average lifetime, and fluorescence decay parameters owing to changes in collagen, elastin, and cellular content between normal and grafted tissue regions. These results lay the foundation for the application of a catheter-based technique for in vivo evaluation of vascular grafts using TRFS and UBM.
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Affiliation(s)
- Hussain Fatakdawala
- University of California Davis, Department of Biomedical Engineering, 451 East Health Sciences Drive, Davis, California 95616, United States
| | - Leigh G. Griffiths
- University of California Davis, Department of Medicine and Epidemiology, VM2 Building, Davis, California 95618, United States
| | - Sterling Humphrey
- University of California Davis, Department of Surgery, 2221 Stockton Boulevard, Sacramento, California 95817, United States
| | - Laura Marcu
- University of California Davis, Department of Biomedical Engineering, 451 East Health Sciences Drive, Davis, California 95616, United States
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