1. Articles from Roman Kuranov

    1-10 of 10
    1. High-speed balanced-detection visible-light optical coherence tomography in the human retina using subpixel spectrometer calibration

      High-speed balanced-detection visible-light optical coherence tomography in the human retina using subpixel spectrometer calibration

      Increases in speed and sensitivity enabled rapid clinical adoption of optical coherence tomography (OCT) in ophthalmology. Recently, visible-light OCT (vis-OCT) achieved ultrahigh axial resolution, improved tissue contrast, and provided new functional imaging capabilities, demonstrating the potential to improve clinical care further. However, limited speed and sensitivity caused by the high relative intensity noise (RIN) in supercontinuum lasers impeded the clinical adoption of vis-OCT. To overcome these limitations, we developed balanced-detection vis-OCT (BD-vis-OCT), which uses two calibrated spectrometers to cancel RIN and other noises. We analyzed the RIN to achieve robust subpixel calibration between the two spectrometers and showed that BD-vis-OCT ...

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    2. Balanced-detection visible-light optical coherence tomography

      Balanced-detection visible-light optical coherence tomography

      Increases in speed and sensitivity enabled rapid clinical adoption of optical coherence tomography (OCT) in ophthalmology. Recently visible-light OCT (vis-OCT) achieved ultrahigh axial resolution, improved tissue contrast, and new functional imaging capabilities, demonstrating the potential to improve clincal care further. However, limited speed and sensitivity caused by the high relative intensity noise (RIN) in supercontinuum lasers impeded the clinical adoption of vis-OCT. To overcome these limitations, we developed balanced-detection vis-OCT (BD-vis-OCT), which uses two calibrated spectrometers to cancel noises common to sample and reference arms, including RIN. We analyzed the RIN to achieve a robust pixel-to-pixel calibration between the two ...

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    3. In Vivo Sublayer Analysis Of Human Retinal Inner Plexiform Layer Obtained By Visible-Light Optical Coherence Tomography

      In Vivo Sublayer Analysis Of Human Retinal Inner Plexiform Layer Obtained By Visible-Light Optical Coherence Tomography

      Purpose: Growing evidence suggests, in glaucoma, the dendritic degeneration of subpopulation of the retinal ganglion cells (RGCs) may precede RGCs soma death. Since different RGCs synapse in different IPL sublayers, visualization of the lamellar structure of the IPL could enable both clinical and fundamental advances in glaucoma understanding and management. In this pilot study, we investigated whether visible-light optical coherence tomography (vis-OCT) could detect the difference in the inner plexiform layer (IPL) sublayers thicknesses between small cohorts of healthy and glaucomatous subjects. Method: We investigated vis-OCT retinal images from nine healthy and five glaucomatous subjects. Four of the healthy subjects ...

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    4. VIS-OCT needs stable, versatile light sources

      VIS-OCT needs stable, versatile light sources

      Optical coherence tomography (OCT) is the gold standard for noninvasive retinal imaging, enabling ophthalmologists to diagnose and treat multiple ocular diseases. Compared to traditional OCT, which uses near-infrared (NIR) wavelengths of light, visible-light OCT (VIS-OCT) offers superior spatial resolution and novel functional imaging capabilities. VIS-OCT provides the most accurate means for measuring retinal oxygen saturation, a key biomarker for understanding changes in tissue metabolism associated with the pathology of various retinal diseases. Traditional OCT has dominated ophthalmic diagnostics for the past 30 years. Thanks to investment in and development of key OCT components, there is an opportunity to accelerate adoption ...

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    5. Spectrally dependent roll-off in visible-light optical coherence tomography

      Spectrally dependent roll-off in visible-light optical coherence tomography

      Recent development of visible-light optical coherence tomography (vis-OCT) has introduced new applications for noninvasive spectroscopic imaging. However, the measured spectra may be altered by spectrally dependent roll-off (SDR). We formulated a mathematical model for SDR that accounted for nonuniform wavenumber spacing, optical aberrations, and misalignments in the spectrometer. We simulated SDR based on this model and found strong agreement with measurements from a vis-OCT system. We verified that SDR altered spectroscopic measurements of fully oxygenated blood. We corrected these alterations by normalizing each spectrally dependent A-line by the measured SDR of the spectrometer. Our investigations of SDR are critical for ...

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    6. Longitudinal deep-brain imaging in mouse using visible-light optical coherence tomography through chronic microprism cranial window

      Longitudinal deep-brain imaging in mouse using visible-light optical coherence tomography through chronic microprism cranial window

      We longitudinally imaged both the superficial and deep cortical microvascular networks in brains of healthy mice and in a mouse model of stroke in vivo using visible-light optical coherence tomography (vis-OCT). We surgically implanted a microprism in mouse brains sealed by a chronic cranial window. The microprism enabled vis-OCT to image the entire depth of the mouse cortex. Following microprism implantation, we imaged the mice for 28 days and found that that it took around 15 days for both the superficial and deep cortical microvessels to recover from the implantation surgery. After the brains recovered, we introduced ischemic strokes by ...

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    7. Speckle reduction in visible-light optical coherence tomography using scan modulation

      Speckle reduction in visible-light optical coherence tomography using scan modulation

      We present a technique to reduce speckle in visible-light optical coherence tomography (vis-OCT) that preserves fine structural details and is robust against sample motion. Specifically, we locally modulate B-scans orthogonally to their axis of acquisition. Such modulation enables acquisition of uncorrelated speckle patterns from similar anatomical locations, which can be averaged to reduce speckle. To verify the effectiveness of speckle reduction, we performed in-vivo retinal imaging using modulated raster and circular scans in both mice and humans. We compared speckle-reduced vis-OCT images with the images acquired with unmodulated B-scans from the same anatomical locations. We compared contrast-to-noise ratio (CNR) and ...

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    8. Apparatus and methods for uniform frequency sample clocking

      Apparatus and methods for uniform frequency sample clocking
      A method and a system for Uniform Frequency Sample Clocking to directly sample the OCT signal with a temporally-non-linear sampling clock derived from a k-space wavemeter on the external sample clock input port of a digitizer. The Uniform Frequency Sample Clocking comprises at least one Pathway, which includes characterizing the swept light source, creating a digital representation of the waveform based from the characterization data, and generating a clock signal using a waveform generator to output the clock signal to a digitizer external clock.
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    9. Depth resolved photothermal OCT detection of macrophages in tissue using nanorose

      Depth resolved photothermal OCT detection of macrophages in tissue using nanorose

      Application of photothermal Optical Coherence Tomography (OCT) to detect macrophages in ex vivo rabbit arteries which have engulfed nanoclusters of gold coated iron oxide (nanorose) is reported. Nanorose engulfed by macrophages associated with atherosclerotic lesions in rabbit arteries absorb incident laser (800nm) energy and cause optical pathlength (OP) variation which is measured using photothermal OCT. OP variation in polydimethyl siloxane tissue phantoms containing varying concentrations of nanorose match values predicted from nanoparticle and material properties. Measurement of OP variation in rabbit arteries in response to laser excitation provides an estimate of nanorose concentration in atherosclerotic lesions of 2.5x109 particles ...

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    1-10 of 10
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  2. Topics in the News

    1. (7 articles) Northwestern University
    2. (4 articles) Opticent Health
    3. (2 articles) NYU Langone Medical Center
    4. (2 articles) University of Texas at Austin
    5. (1 articles) University of Texas Health Science Center
    6. (1 articles) Volcano Corporation
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    Depth resolved photothermal OCT detection of macrophages in tissue using nanorose Apparatus and methods for uniform frequency sample clocking Methods And Apparatus Related To Photothermal Optical Coherence Tomography (Oct) Speckle reduction in visible-light optical coherence tomography using scan modulation Longitudinal deep-brain imaging in mouse using visible-light optical coherence tomography through chronic microprism cranial window Spectrally dependent roll-off in visible-light optical coherence tomography VIS-OCT needs stable, versatile light sources In Vivo Sublayer Analysis Of Human Retinal Inner Plexiform Layer Obtained By Visible-Light Optical Coherence Tomography Balanced-detection visible-light optical coherence tomography High-speed balanced-detection visible-light optical coherence tomography in the human retina using subpixel spectrometer calibration Normative data and associations of Optical Coherence Tomography Angiography measurements of the macula: The Singapore Malay Eye Study Automatic Segmentation and Measurement of Choroid Layer in High Myopia for OCT Imaging Using Deep Learning