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Wang A, Qi W, Gao T, Tang X. Molecular Contrast Optical Coherence Tomography and Its Applications in Medicine. Int J Mol Sci 2022; 23:ijms23063038. [PMID: 35328454 PMCID: PMC8949853 DOI: 10.3390/ijms23063038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/05/2022] [Accepted: 03/08/2022] [Indexed: 12/28/2022] Open
Abstract
The growing need to understand the molecular mechanisms of diseases has prompted the revolution in molecular imaging techniques along with nanomedicine development. Conventional optical coherence tomography (OCT) is a low-cost in vivo imaging modality that provides unique high spatial and temporal resolution anatomic images but little molecular information. However, given the widespread adoption of OCT in research and clinical practice, its robust molecular imaging extensions are strongly desired to combine with anatomical images. A range of relevant approaches has been reported already. In this article, we review the recent advances of molecular contrast OCT imaging techniques, the corresponding contrast agents, especially the nanoparticle-based ones, and their applications. We also summarize the properties, design criteria, merit, and demerit of those contrast agents. In the end, the prospects and challenges for further research and development in this field are outlined.
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Palma-Chavez JA, Kim W, Serafino M, Jo JA, Charoenphol P, Applegate BE. Methylene blue-filled biodegradable polymer particles as a contrast agent for optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2020; 11:4255-4274. [PMID: 32923040 PMCID: PMC7449750 DOI: 10.1364/boe.399322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 05/11/2023]
Abstract
Optical coherence tomography (OCT) images largely lack molecular information or molecular contrast. We address that issue here, reporting on the development of biodegradable micro and nano-spheres loaded with methylene blue (MB) as molecular contrast agents for OCT. MB is a constituent of FDA approved therapies and widely used as a dye in off-label clinical applications. The sequestration of MB within the polymer reduced toxicity and improved signal strength by drastically reducing the production of singlet oxygen and leuco-MB. The former leads to tissue damage and the latter to reduced image contrast. The spheres are also strongly scattering which improves molecular contrast signal localization and enhances signal strength. We demonstrate that these contrast agents may be imaged using both pump-probe OCT and photothermal OCT, using a 830 nm frequency domain OCT system and a 1.3 µm swept source OCT system. We also show that these contrast agents may be functionalized and targeted to specific receptors, e.g. the VCAM receptor known to be overexpressed in inflammation.
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Affiliation(s)
- Jorge A. Palma-Chavez
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Wihan Kim
- Department of Otolaryngology–Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Michael Serafino
- Department of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Javier A. Jo
- Department of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Phapanin Charoenphol
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Brian E. Applegate
- Department of Otolaryngology–Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
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3
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In vivo photothermal optical coherence tomography of endogenous and exogenous contrast agents in the eye. Sci Rep 2017; 7:9228. [PMID: 28835698 PMCID: PMC5569082 DOI: 10.1038/s41598-017-10050-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 08/02/2017] [Indexed: 11/08/2022] Open
Abstract
Optical coherence tomography (OCT) has become a standard-of-care in retinal imaging. OCT allows non-invasive imaging of the tissue structure but lacks specificity to contrast agents that could be used for in vivo molecular imaging. Photothermal OCT (PT-OCT) is a functional OCT-based technique that has been developed to detect absorbers in a sample. We demonstrate in vivo PT-OCT in the eye for the first time on both endogenous (melanin) and exogenous (gold nanorods) absorbers. Pigmented mice and albino mice (n = 6 eyes) were used to isolate the photothermal signal from the melanin in the retina. Pigmented mice with laser-induced choroidal neovascularization lesions (n = 7 eyes) were also imaged after a systemic injection of gold nanorods to observe their passive accumulation in the retina. This experiment demonstrates the feasibility of PT-OCT to image the distribution of both endogenous and exogenous absorbers in the mouse retina.
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Robles FE, Zhou KC, Fischer MC, Warren WS. Stimulated Raman scattering spectroscopic optical coherence tomography. OPTICA 2017; 4:243-246. [PMID: 29302608 PMCID: PMC5749255 DOI: 10.1364/optica.4.000243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We integrate spectroscopic optical coherence tomography (SOCT) with stimulated Raman scattering (SRS) to enable simultaneously multiplexed spatial and spectral imaging with sensitivity to many endogenous biochemical species that play an important role in biology and medicine. The combined approach, termed SRS-SOCT, overcomes the limitations of each individual method. Ultimately, SRS-SOCT has the potential to achieve fast, volumetric, and highly sensitive label-free molecular imaging. We demonstrate the approach by imaging excised human adipose tissue and detecting the lipids' Raman signatures in the high-wavenumber region.
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Affiliation(s)
- Francisco E. Robles
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Currently at Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory School of Medicine, tlanta, Georgia 30332, USA
| | - Kevin C. Zhou
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Martin C. Fischer
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Warren S. Warren
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
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Robles FE, Fischer MC, Warren WS. Dispersion-based stimulated Raman scattering spectroscopy, holography, and optical coherence tomography. OPTICS EXPRESS 2016; 24:485-98. [PMID: 26832279 PMCID: PMC4741354 DOI: 10.1364/oe.24.000485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Stimulated Raman scattering (SRS) enables fast, high resolution imaging of chemical constituents important to biological structures and functional processes, both in a label-free manner and using exogenous biomarkers. While this technology has shown remarkable potential, it is currently limited to point scanning and can only probe a few Raman bands at a time (most often, only one). In this work we take a fundamentally different approach to detecting the small nonlinear signals based on dispersion effects that accompany the loss/gain processes in SRS. In this proof of concept, we demonstrate that the dispersive measurements are more robust to noise compared to amplitude-based measurements, which then permit spectral or spatial multiplexing (potentially both, simultaneously). Finally, we illustrate how this method may enable different strategies for biochemical imaging using phase microscopy and optical coherence tomography.
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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.
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Affiliation(s)
- Jina Kim
- Department of Surgery, Duke University, Durham, NC 27710, USA
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Makita S, Yasuno Y. In vivo photothermal optical coherence tomography for non-invasive imaging of endogenous absorption agents. BIOMEDICAL OPTICS EXPRESS 2015; 6:1707-25. [PMID: 26137374 PMCID: PMC4467701 DOI: 10.1364/boe.6.001707] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 04/04/2015] [Indexed: 05/19/2023]
Abstract
In vivo photothermal optical coherence tomography (OCT) is demonstrated for cross-sectional imaging of endogenous absorption agents. In order to compromise the sensitivity, imaging speed, and sample motion immunity, a new photothermal detection scheme and phase processing method are developed. Phase-resolved swept-source OCT and fiber-pigtailed laser diode (providing excitation at 406 nm) are combined to construct a high-sensitivity photothermal OCT system. OCT probe and excitation beam coaxially illuminate and are focused on tissues. The photothermal excitation and detection procedure is designed to obtain high efficiency of photothermal effect measurement. The principle and method of depth-resolved cross-sectional imaging of absorption agents with photothermal OCT has been derived. The phase-resolved thermal expansion detection algorithm without motion artifact enables in vivo detection of photothermal effect. Phantom imaging with a blood phantom and in vivo human skin imaging are conducted. A phantom with guinea-pig blood as absorber has been scanned by the photothermal OCT system to prove the concept of cross-sectional absorption agent imaging. An in vivo human skin measurement is also performed with endogenous absorption agents.
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Affiliation(s)
- Shuichi Makita
- Computational Optics Group, University of Tsukuba, Tsukuba, 305-8573,
Japan
| | - Yoshiaki Yasuno
- Computational Optics Group, University of Tsukuba, Tsukuba, 305-8573,
Japan
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Abstract
An 830-nm spectral-domain optical coherence tomography (OCT) system with an integrated 663-nm diode pump laser has been developed to enable molecular contrast OCT imaging of methylene blue (MB), a common vital dye used clinically. The introduction of the 663-nm diode laser, which acts as the pump in this implementation of pump-probe OCT (PPOCT), represents a minor modification to an otherwise typical OCT system. A newly developed background subtraction technique completely removes all background from intensity noise at the pump modulation frequency, simplifying the interpretation of PPOCT images. These developments have enabled the first in vivo imaging of MB with PPOCT. Volumetric images of a zebrafish, stained by submersion in a 0.01% (w/v) solution of MB for 6 h, show accumulation of MB in the mesonephros, the primordial filtration organ.
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Affiliation(s)
- Wihan Kim
- Department of Biomedical Engineering, 5045 Emerging Technology Building, 3120 Texas A&M University, College Station, TX 77843, USA
| | - Brian E. Applegate
- Department of Biomedical Engineering, 5045 Emerging Technology Building, 3120 Texas A&M University, College Station, TX 77843, USA
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Carrasco-Zevallos O, Shelton RL, Kim W, Pearson J, Applegate BE. In vivo pump-probe optical coherence tomography imaging in Xenopus laevis. JOURNAL OF BIOPHOTONICS 2015; 8:25-35. [PMID: 24282110 PMCID: PMC4955517 DOI: 10.1002/jbio.201300119] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/30/2013] [Accepted: 10/30/2013] [Indexed: 05/25/2023]
Abstract
Currently, optical coherence tomography (OCT), is not capable of obtaining molecular information often crucial for identification of disease. To enable molecular imaging with OCT, we have further developed a technique that harnesses transient changes in light absorption in the sample to garner molecular information. A Fourier-domain Pump-Probe OCT (PPOCT) system utilizing a 532 nm pump and 830 nm probe has been developed for imaging hemoglobin. Methylene blue, a biological dye with well-know photophysics, was used to characterize the system before investigating the origin of the hemoglobin PPOCT signal. The first in vivo PPOCT images were recorded of the vasculature in Xenopus laevis. The technique was shown to work equally well in flowing and nonflowing vessels. Furthermore, PPOCT was compared with other OCT extensions which require flow, such as Doppler OCT and phase-variance OCT. PPOCT was shown to better delineate tortuous vessels, where nodes often restrict Doppler and phase-variance reconstruction.
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Affiliation(s)
- Oscar Carrasco-Zevallos
- Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA
| | - Ryan L. Shelton
- Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA
| | - Wihan Kim
- Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA
| | - Jeremy Pearson
- Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA
| | - Brian E. Applegate
- Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA
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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.
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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:
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Mattison SP, Kim W, Park J, Applegate BE. Molecular Imaging in Optical Coherence Tomography. CURRENT MOLECULAR IMAGING 2014; 3:88-105. [PMID: 25821718 PMCID: PMC4373611 DOI: 10.2174/2211555203666141117233442] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Optical coherence tomography (OCT) is a medical imaging technique that provides tomographic images at micron scales in three dimensions and high speeds. The addition of molecular contrast to the available morphological image holds great promise for extending OCT's impact in clinical practice and beyond. Fundamental limitations prevent OCT from directly taking advantage of powerful molecular processes such as fluorescence emission and incoherent Raman scattering. A wide range of approaches is being researched to provide molecular contrast to OCT. Here we review those approaches with particular attention to those that derive their molecular contrast directly from modulation of the OCT signal. We also provide a brief overview of the multimodal approaches to gaining molecular contrast coincident with OCT.
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Affiliation(s)
| | | | - Jesung Park
- Department of Biomedical Engineering, Texas A&M University, 3120 TAMU, College Station, TX 77843
| | - Brian E. Applegate
- Department of Biomedical Engineering, Texas A&M University, 3120 TAMU, College Station, TX 77843
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12
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Tucker-Schwartz JM, Beavers KR, Sit WW, Shah AT, Duvall CL, Skala MC. In vivo imaging of nanoparticle delivery and tumor microvasculature with multimodal optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2014; 5:1731-43. [PMID: 24940536 PMCID: PMC4052907 DOI: 10.1364/boe.5.001731] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/25/2014] [Accepted: 04/28/2014] [Indexed: 05/03/2023]
Abstract
Current imaging techniques capable of tracking nanoparticles in vivo supply either a large field of view or cellular resolution, but not both. Here, we demonstrate a multimodality imaging platform of optical coherence tomography (OCT) techniques for high resolution, wide field of view in vivo imaging of nanoparticles. This platform includes the first in vivo images of nanoparticle pharmacokinetics acquired with photothermal OCT (PTOCT), along with overlaying images of microvascular and tissue morphology. Gold nanorods (51.8 ± 8.1 nm by 15.2 ± 3.3 nm) were intravenously injected into mice, and their accumulation into mammary tumors was non-invasively imaged in vivo in three dimensions over 24 hours using PTOCT. Spatial frequency analysis of PTOCT images indicated that gold nanorods reached peak distribution throughout the tumors by 16 hours, and remained well-dispersed up to 24 hours post-injection. In contrast, the overall accumulation of gold nanorods within the tumors peaked around 16 hours post-injection. The accumulation of gold nanorods within the tumors was validated post-mortem with multiphoton microscopy. This shows the utility of PTOCT as part of a powerful multimodality imaging platform for the development of nanomedicines and drug delivery technologies.
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Affiliation(s)
| | - Kelsey R. Beavers
- Interdisciplinary Graduate Program in Materials Science, Vanderbilt University, Nashville, TN 37235, USA
| | - Wesley W. Sit
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Amy T. Shah
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Craig L. Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Melissa C. Skala
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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Oldenburg AL, Chhetri RK, Cooper JM, Wu WC, Troester MA, Tracy JB. Motility-, autocorrelation-, and polarization-sensitive optical coherence tomography discriminates cells and gold nanorods within 3D tissue cultures. OPTICS LETTERS 2013; 38:2923-6. [PMID: 23903180 PMCID: PMC3856705 DOI: 10.1364/ol.38.002923] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We propose a method for differentiating classes of light scatterers based upon their temporal and polarization properties computed from time series of polarization-sensitive optical coherence tomography (PS-OCT) images. The amplitude (motility) and time scale (autocorrelation decay time) of the speckle fluctuations are combined with the cross-polarization pixel-wise to render Motility-, autocorrelation-, and polarization-sensitive (MAPS) OCT contrast images. This combination of metrics provides high specificity for discriminating diffusive gold nanorods and mammary epithelial cell spheroids within 3D tissue culture, based on their unique MAPS signature. This has implications toward highly specific contrast in molecular (nanoparticle-based) and functional (cellular activity) imaging using standard PS-OCT hardware.
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Affiliation(s)
- Amy L Oldenburg
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255, USA.
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Robles FE, Samineni P, Wilson JW, Warren WS. Pump-probe nonlinear phase dispersion spectroscopy. OPTICS EXPRESS 2013; 21:9353-64. [PMID: 23609646 PMCID: PMC3656694 DOI: 10.1364/oe.21.009353] [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: 02/13/2013] [Revised: 04/01/2013] [Accepted: 04/04/2013] [Indexed: 05/22/2023]
Abstract
Pump-probe microscopy is an imaging technique that delivers molecular contrast of pigmented samples. Here, we introduce pump-probe nonlinear phase dispersion spectroscopy (PP-NLDS), a method that leverages pump-probe microscopy and spectral-domain interferometry to ascertain information from dispersive and resonant nonlinear effects. PP-NLDS extends the information content to four dimensions (phase, amplitude, wavelength, and pump-probe time-delay) that yield unique insight into a wider range of nonlinear interactions compared to conventional methods. This results in the ability to provide highly specific molecular contrast of pigmented and non-pigmented samples. A theoretical framework is described, and experimental results and simulations illustrate the potential of this method. Implications for biomedical imaging are discussed.
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Affiliation(s)
- Francisco E Robles
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
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Tucker-Schwartz JM, Meyer TA, Patil CA, Duvall CL, Skala MC. In vivo photothermal optical coherence tomography of gold nanorod contrast agents. BIOMEDICAL OPTICS EXPRESS 2012; 3:2881-95. [PMID: 23162726 PMCID: PMC3493242 DOI: 10.1364/boe.3.002881] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 10/12/2012] [Accepted: 10/15/2012] [Indexed: 05/18/2023]
Abstract
Photothermal optical coherence tomography (PT-OCT) is a potentially powerful tool for molecular imaging. Here, we characterize PT-OCT imaging of gold nanorod (GNR) contrast agents in phantoms, and we apply these techniques for in vivo GNR imaging. The PT-OCT signal was compared to the bio-heat equation in phantoms, and in vivo PT-OCT images were acquired from subcutaneous 400 pM GNR Matrigel injections into mice. Experiments revealed that PT-OCT signals varied as predicted by the bio-heat equation, with significant PT-OCT signal increases at 7.5 pM GNR compared to a scattering control (p < 0.01) while imaging in common path configuration. In vivo PT-OCT images demonstrated an appreciable increase in signal in the presence of GNRs compared to controls. Additionally, in vivo PT-OCT GNR signals were spatially distinct from blood vessels imaged with Doppler OCT. We anticipate that the demonstrated in vivo PT-OCT sensitivity to GNR contrast agents is sufficient to image molecular expression in vivo. Therefore, this work demonstrates the translation of PT-OCT to in vivo imaging and represents the next step towards its use as an in vivo molecular imaging tool.
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Catalano O. Critical analysis of the ultrasonographic criteria for diagnosing lymph node metastasis in patients with cutaneous melanoma: a systematic review. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2011; 30:547-560. [PMID: 21460155 DOI: 10.7863/jum.2011.30.4.547] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The purpose of this systematic review of the literature was to evaluate the use of ultrasonography (US) in the assessment of lymph node metastasis in patients with cutaneous melanoma. A multimodal strategy was used, which was mainly based on a PubMed database search. Among the 201 cumulative articles collected (years 1989-2009), 31 were found to match all of the inclusion criteria and to provide a description of the use of US scanning in lymph node melanoma metastasis. Data extracted included the author's name and country, journal and year of publication, prospective or retrospective nature of the study, single-center or multicenter nature of the study, period when US studies were performed, US transducers used, gray scale and color Doppler criteria used for diagnosis, and data on US accuracy. The diagnostic criteria used in the 31 selected articles were critically reviewed, illustrating to the reader the discrepancies and unclear aspects identified. On the basis of this review, the need to establish definitive, clearly defined, and univocal diagnostic criteria to be applied in daily clinical practice as well as to be used in articles to be published is emphasized.
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Affiliation(s)
- Orlando Catalano
- First Department of Radiology, National Cancer Institute Fondazione G. Pascale, Naples, Italy.
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