1. Articles from bioRxiv.org

    biorxiv.org

  2. 1-7 of 7
    1. Aperture Phase Modulation with Adaptive Optics: A Novel Approach for Speckle Reduction and Structure Extraction in Optical Coherence Tomography

      Aperture Phase Modulation with Adaptive Optics: A Novel Approach for Speckle Reduction and Structure Extraction in Optical Coherence Tomography

      Speckle is an inevitable consequence of the use of coherent light in optical coherence tomography (OCT), and often acts as noise that obscures micro-structures of biological tissue. We here present a novel method of suppressing speckle noise intrinsically compatible with adaptive optics (AO) in OCT system: by modulating the phase inside the imaging system pupil aperture with a segmented deformable mirror, thus producing minor perturbations in the point spread function (PSF) to create un-correlated speckle pattern between B-scans, and further averaging to wash out the speckle but maintain the structures. It is a well-controlled and universal method which can efficiently ...

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    2. Functional retinal imaging using adaptive optics swept-source OCT at 1.6MHz

      Functional retinal imaging using adaptive optics swept-source OCT at 1.6MHz

      bjective optical assessment of photoreceptor function may permit earlier diagnosis of retinal disease than current methods such as perimetry, electrophysiology, and clinical imaging. In this work, we describe an adaptive optics (AO) optical coherence tomography (OCT) system designed to measure functional responses of single cones to visible stimuli. The OCT subsystem consisted of a raster-scanning Fourier-domain mode-locked laser that acquires A-scans at 1.64MHz with a center wavelength of 1063nm, and an AO subsystem providing diffraction-limited imaging. Analysis of serial volumetric images revealed phase changes of cone photoreceptors consistent with outer segment elongation and proportional to stimulus intensity, as well ...

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    3. Spectral Contrast Optical Coherence Tomography Angiography Enables Single-Scan Vessel Imaging

      Spectral Contrast Optical Coherence Tomography Angiography Enables Single-Scan Vessel Imaging

      Optical Coherence Tomography angiography relies on motion for contrast and requires at least two data acquisitions per point-wise scanning location. We present a method termed Spectral Contrast Optical Coherence Tomography Angiography using visible light which relies on the spectral signatures of blood to obtain angiography from a single scan using endogenous contrast. We demonstrate the molecular sensitivity of this method enabling lymphatic, blood, and tissue discrimination.

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    4. Microscale light management and inherent optical properties of intact corals studied with optical coherence tomography

      Microscale light management and inherent optical properties of intact corals studied with optical coherence tomography

      Coral reefs are highly productive photosynthetic systems and coral optics studies suggest that such high efficiency is due to optimised light scattering by coral tissue and skeleton. Here, we characterise the inherent optical properties, i.e., the scattering coefficient, μ s , and the anisotropy of scattering, g , of 8 intact coral species using optical coherence tomography (OCT). Specifically, we describe light scattering by coral skeletons, coenoarc tissues, polyp tentacles and areas covered by fluorescent pigments (FP). Our results reveal that light scattering between coral species ranges from μ s = 3 mm -1 ( Stylophora pistillata ) to μ s = 25 mm -1 ( Echinopora lamelosa ). For ...

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    5. Generating perfusion maps from structural optical coherence tomography with artificial intelligence

      Generating perfusion maps from structural optical coherence tomography with artificial intelligence

      Despite significant advances in artificial intelligence (AI) for computer vision, its application in medical imaging has been limited by the burden and limits of expert-generated labels. We used images from optical coherence tomography angiography (OCTA), a relatively new imaging modality that measures perfusion of the retinal vasculature, to train an AI algorithm to generate vasculature maps from standard structural optical coherence tomography (OCT) images of the same retinae, both exceeding the ability and bypassing the need for expert labeling. Deep learning was able to infer perfusion of microvasculature from structural OCT images with similar fidelity to OCTA and significantly better ...

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    6. Optical Coherence Tomography Reveals Mechanobiologically Stable Self-Organizing Di-Fork Architecture of Mice Cutaneous Scars

      Optical Coherence Tomography Reveals Mechanobiologically Stable Self-Organizing Di-Fork Architecture of Mice Cutaneous Scars

      Scientific studies report crucial impacts of biomechanical effectors to modulate wound healing either by scarring or regeneration. Further, the biological decision to predominantly favor the former is still cryptic. Real-time visualization of biomechanical manifestations in situ in scarring is hence necessary. Endorsed by nanostructural testing, synthetic phantom analysis, and computational simulations, we found strong mechanobiological correlates for Swept Source Optical Coherence Tomography (SS-OCT) speckles in mice cutaneous repair (full-thickness) up to 10 months. The theoretical basis of the optomechanics to provide insights into scar form-factor and evolution is proposed. Optomechanical changes have been considered as the resultant of intrinsic (e ...

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    7. In vivo imaging of coral tissue and skeleton with optical coherence tomography

      In vivo imaging of coral tissue and skeleton with optical coherence tomography

      Optical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissues in vivo and in real time. We present the first application of OCT for in vivo imaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host ...

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    1-7 of 7
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