1. Articles from Debasish Sen

    1-8 of 8
    1. Optical coherence tomography of lymphatic vessel endothelial hyaluronan receptors in vivo

      Optical coherence tomography of lymphatic vessel endothelial hyaluronan receptors in vivo

      Optical Coherence Tomography (OCT) imaging of living subjects offers millimeters depth of penetration into tissue while maintaining high spatial resolution. However, because most molecular biomarkers do not produce inherent OCT contrast signals, exogenous contrast agents must be employed to achieve molecular imaging. Here we demonstrate that microbeads (μBs) can be used as effective contrast agents to target cellular biomarkers in lymphatic vessels and can be detected by OCT using a phase variance algorithm. We applied this technique to image the molecular dynamics of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) in vivo , which showed significant down-regulation during tissue inflammation.

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    2. Speckle-modulating optical coherence tomography in living mice and humans

      Speckle-modulating optical coherence tomography in living mice and humans

      Optical coherence tomography (OCT) is a powerful biomedical imaging technology that relies on the coherent detection of backscattered light to image tissue morphology in vivo . As a consequence, OCT is susceptible to coherent noise (speckle noise), which imposes significant limitations on its diagnostic capabilities. Here we show speckle-modulating OCT (SM-OCT), a method based purely on light manipulation that virtually eliminates speckle noise originating from a sample. SM-OCT accomplishes this by creating and averaging an unlimited number of scans with uncorrelated speckle patterns without compromising spatial resolution. Using SM-OCT, we reveal small structures in the tissues of living animals, such as ...

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    3. In Vivo Molecular Optical Coherence Tomography of Lymphatic Vessel Endothelial Hyaluronan Receptors

      In Vivo Molecular Optical Coherence Tomography of Lymphatic Vessel Endothelial Hyaluronan Receptors

      Optical Coherence Tomography (OCT) imaging of living subjects offers increased depth of penetration while maintaining high spatial resolution when compared to other optical microscopy techniques. However, since most protein biomarkers do not exhibit inherent contrast detectable by OCT, exogenous contrast agents must be employed for imaging specific cellular biomarkers of interest. While a number of OCT contrast agents have been previously studied, demonstrations of molecular targeting with such agents in live animals have been historically challenging and notably limited in success. Here we demonstrate for the first time that microbeads (µBs) can be used as contrast agents to target cellular ...

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    4. Spectral contrast-enhanced optical coherence tomography for improved detection of tumor microvasculature and functional imaging of lymphatic drainage

      Spectral contrast-enhanced optical coherence tomography for improved detection of tumor microvasculature and functional imaging of lymphatic drainage

      Optical Coherence Tomography (OCT) is well-suited to study in vivo dynamics of blood circulation and lymphatic flow because of the technique’s combination of rapid image acquisition, micron spatial resolution, and penetration depth in turbid tissues. However, OCT has been historically constrained by a dearth of contrast agents that are readily distinguished from the strong scattering intrinsic to biological tissues. In this study, we demonstrate large gold nanorods (LGNRs) as optimized contrast agents for OCT. LGNRs produce 32-fold greater backscattering than GNRs previously tested for contrast-enhanced OCT. Furthermore, LGNRs exhibit 110-fold stronger spectral signal than conventional GNRs when coupled with ...

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    5. High sensitivity contrast enhanced optical coherence tomography for functional in vivo imaging

      High sensitivity contrast enhanced optical coherence tomography for functional in vivo imaging

      In this study, we developed and applied highly-scattering large gold nanorods (LGNRs) and custom spectral detection algorithms for high sensitivity contrast-enhanced optical coherence tomography (OCT). We were able to detect LGNRs at a concentration as low as 50 pM in blood. We used this approach for noninvasive 3D imaging of blood vessels deep in solid tumors in living mice. Additionally, we demonstrated multiplexed imaging of spectrally-distinct LGNRs that enabled observations of functional drainage in lymphatic networks. This method, which we call MOZART, provides a platform for molecular imaging and characterization of tissue noninvasively at cellular resolution

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    6. High-resolution contrast-enhanced optical coherence tomography in mice retinae

      High-resolution contrast-enhanced optical coherence tomography in mice retinae

      Optical coherence tomography (OCT) is a noninvasive interferometric imaging modality providing anatomical information at depths of millimeters and a resolution of micrometers. Conventional OCT images limit our knowledge to anatomical structures alone, without any contrast enhancement. Therefore, here we have, for the first time, optimized an OCT-based contrast-enhanced imaging system for imaging single cells and blood vessels in vivo inside the living mouse retina at subnanomolar sensitivity. We used bioconjugated gold nanorods (GNRs) as exogenous OCT contrast agents. Specifically, we used anti-mouse CD45 coated GNRs to label mouse leukocytes and mPEG-coated GNRs to determine sensitivity of GNR detection in vivo ...

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    7. Feature of the Week 04/02/2016: Contrast-Enhanced Optical Coherence Tomography with Picomolar Sensitivity for Functional in vivo Imaging (with Audio)

      Feature of the Week 04/02/2016:  Contrast-Enhanced Optical Coherence Tomography with Picomolar Sensitivity for Functional in vivo Imaging (with Audio)

      Optical Coherence Tomography (OCT) enables real-time imaging of living tissues with cellular resolution over large 3D fields of view.[1] However, functional and molecular capabilities for OCT remain elusive due to the difficulties of distinguishing exogenous contrast agents from intrinsic tissue scattering and absorption. Previous reports have detailed the use of magnetic probes,[2] absorbent dyes,[3] and gold nanoparticles[4] to produce OCT contrast enhancement through various mechanisms. In the current study, optimized large gold nanorods (LGNRs) and a customized aberration-free spectral detection algorithm were developed to demonstrate an improved platform for molecular imaging with OCT. LGNRs, which produce ...

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    8. Contrast-enhanced optical coherence tomography with picomolar sensitivity for functional in vivo imaging

      Contrast-enhanced optical coherence tomography with picomolar sensitivity for functional in vivo imaging

      Optical Coherence Tomography (OCT) enables real-time imaging of living tissues at cell-scale resolution over millimeters in three dimensions. Despite these advantages, functional biological studies with OCT have been limited by a lack of exogenous contrast agents that can be distinguished from tissue. Here we report an approach to functional OCT imaging that implements custom algorithms to spectrally identify unique contrast agents: large gold nanorods (LGNRs). LGNRs exhibit 110-fold greater spectral signal per particle than conventional GNRs, which enables detection of individual LGNRs in water and concentrations as low as 250 pM in the circulation of living mice. This translates to ...

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    1-8 of 8
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    1. (8 articles) Stanford University
    2. (8 articles) Adam de la Zerda
    3. (8 articles) Debasish Sen
    4. (8 articles) Orly Liba
    5. (6 articles) Elliott D. SoRelle
    6. (2 articles) Siavash Yousefi
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    Contrast-enhanced optical coherence tomography with picomolar sensitivity for functional in vivo imaging Feature of the Week 04/02/2016:  Contrast-Enhanced Optical Coherence Tomography with Picomolar Sensitivity for Functional in vivo Imaging (with Audio) High-resolution contrast-enhanced optical coherence tomography in mice retinae High sensitivity contrast enhanced optical coherence tomography for functional in vivo imaging Spectral contrast-enhanced optical coherence tomography for improved detection of tumor microvasculature and functional imaging of lymphatic drainage In Vivo Molecular Optical Coherence Tomography of Lymphatic Vessel Endothelial Hyaluronan Receptors Speckle-modulating optical coherence tomography in living mice and humans Optical coherence tomography of lymphatic vessel endothelial hyaluronan receptors in vivo A case report of a coronary myocardial bridge with impaired full-cycle ratio during dobutamine challenge Diagnosis of chronic stage of hypertensive retinopathy based on spectral domain optical coherence tomography A Cross-sectional Optical Coherence Tomography Study in Patients on Taxane-based Therapy and A Case Report with the Literature Review Determination of peripapillary vessel density in optic disc drusen using EDI-OCT and OCT angiography