1. Articles from Qian Li

    1-19 of 19
    1. COVID-19 Causes Ciliary Dysfunction as Demonstrated by Human Intranasal Micro-Optical Coherence Tomography Imaging

      COVID-19 Causes Ciliary Dysfunction as Demonstrated by Human Intranasal Micro-Optical Coherence Tomography Imaging

      Severe acute respiratory syndrome coronavirus (SARS-CoV-2), causative agent of coronavirus disease 2019 (COVID-19), binds via ACE2 receptors, highly expressed in ciliated cells of the nasal epithelium. Micro-optical coherence tomography (μOCT) is a minimally invasive intranasal imaging technique that can determine cellular and functional dynamics of respiratory epithelia at 1-μm resolution, enabling real time visualization and quantification of epithelial anatomy, ciliary motion, and mucus transport. We hypothesized that respiratory epithelial cell dysfunction in COVID-19 will manifest as reduced ciliated cell function and mucociliary abnormalities, features readily visualized by μOCT. Symptomatic outpatients with SARS-CoV-2 aged ≥ 18 years were recruited within 14 ...

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    2. Analysis of Radial Peripapillary Capillary Density in Patients with Bietti Crystalline Dystrophy by Optical Coherence Tomography Angiography

      Analysis of Radial Peripapillary Capillary Density in Patients with Bietti Crystalline Dystrophy by Optical Coherence Tomography Angiography

      Objective: We wanted to investigate the radial peripapillary capillary (RPC) network in patients with Bietti crystalline dystrophy (BCD). Methods: We compared RPC densities in the disk and different peripapillary regions, obtained using optical coherence tomography angiography in 22 patients with BCD (37 eyes) and 22 healthy subjects (37 eyes). The BCD group was then divided into Stage 2 and Stage 3 subgroups based on Yuzawa staging, comparing the RPC densities of the two. Results: The disk area RPC density was 38.8% ± 6.3% in the BCD group and 49.2% ± 6.1% in the control group ( P < 0.001 ...

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    3. Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography

      Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography

      Significance: After three decades, more than 75,000 publications, tens of companies being involved in its commercialization, and a global market perspective of about USD 1.5 billion in 2023, optical coherence tomography (OCT) has become one of the fastest successfully translated imaging techniques with substantial clinical and economic impacts and acceptance. Aim: Our perspective focuses on disruptive forward-looking innovations and key technologies to further boost OCT performance and therefore enable significantly enhanced medical diagnosis. Approach: A comprehensive review of state-of-the-art accomplishments in OCT has been performed. Results: The most disruptive future OCT innovations include imaging resolution and speed (single-beam ...

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    4. REAP: Revealing drug tolerant persister cells in cancer using contrast enhanced optical coherence and photoacoustic tomography

      REAP: Revealing drug tolerant persister cells in cancer using contrast enhanced optical coherence and photoacoustic tomography

      Despite chemotherapy, residual tumors often rely on so-called drug tolerant persister (DTP) cells, which evade treatment to give rise to therapy-resistant relapse and refractory disease. Detection of residual tumor cells proves to be challenging because of the rarity and heterogeneity of DTP cells. In the framework of a H2020 project, REAP will gather researchers and engineers from six countries, who will combine their expertise in biology, chemistry, oncology, material sciences, photonics, and electrical and biomedical engineering in the hope of revealing DTPs in cancer using contrast enhanced multimodal optical imaging. Laser sources for photoacoustic microscopy (PAM), photoacoustic tomography (PAT), and ...

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    5. Ultra-high-resolution SD-OCM imaging with a compact polarization-aligned 840 nm broadband combined-SLED source

      Ultra-high-resolution SD-OCM imaging with a compact polarization-aligned 840 nm broadband combined-SLED source

      We analyze the influence of intrinsic polarization alignment on image quality and axial resolution employing a broadband 840 nm light source with an optical bandwidth of 160 nm and an output power of 12 mW tailored for spectral-domain optical coherence microscopy (SD-OCM) applications. Three superluminescent diodes (SLEDs) are integrated into a 14-pin butterfly module using a free-space micro-optical bench architecture, maintaining a constant polarization state across the full spectral output. We demonstrate superior imaging performance in comparison to traditionally coupled-SLED broadband light sources in a teleost model organism in-vivo .

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    6. Retinal neurovascular responses to transcorneal electrical stimulation measured with optical coherence tomography

      Retinal neurovascular responses to transcorneal electrical stimulation measured with optical coherence tomography

      Noninvasive transcorneal electrical stimulation (TES) has emerged as a potential strategy to facilitate visual restoration and promote retinal cell survival for certain retinal and optic nerve diseases owing to its neuroprotective effects. However, the neurovascular responses of retinal neurons evoked by TES have not been completely determined. To investigate this issue, we utilized a custom-designed spectral-domain optical coherence tomography (SD-OCT) to record the retinal neural and vascular responses under TES in vivo simultaneously. Significant increases of both positive and negative intrinsic optical signal (IOS) changes were recorded in all three segmented retinal layers, which mainly related to neural activities. However ...

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    7. Response to Comment on “Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography”

      Response to Comment on “Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography”

      We noticed that Spahr et al. commented on our latest paper “Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography”. In their comments, they concluded that the measured retinal pulse wave velocity (rPWV) in our paper was “highly surprising and contradictory to theoretical predictions and previously published results”. However, we have some different opinions regarding their comments.

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    8. Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      The human eyes provide a natural window for noninvasive measurement of the pulse wave velocity (PWV) of small arteries. By measuring the retinal PWV, the stiffness of small arteries can be assessed, which may better detect early vascular diseases. Therefore, retinal PWV measurement has attracted increasing attention. In this study, a jump-scanning method was proposed for non-invasive measurement of retinal PWV using spectral-domain OCT. The jump-scanning method uses the phase-resolved Doppler OCT to obtain the pulse shapes. To realize PWV measurement, the jump-scanning method extracts the transit time of the pulse wave from an original OCT scanning site to another ...

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    9. Dual band dual focus optical coherence tomography for imaging the whole eye segment

      Dual band dual focus optical coherence tomography for imaging the whole eye segment

      We developed an improved dual band dual focus spectral domain optical coherence tomography (SD-OCT) for in vivo 2D/3D imaging of the whole eye segment, including the whole anterior segment and retina. The system featured two OCT channels with two different bands centered at 840 nm and 1050 nm, which were designed to image the retina and the anterior segments of the eye, respectively. By combing the two probe light beams for co-axial scanning and separating them for focusing at different segments of the eye with a combination of three dichroic mirrors, we not only minimized the loss of the ...

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    10. UTILIZATION OF FUNDUS AUTOFLUORESCENCE, SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY, AND ENHANCED DEPTH IMAGING IN THE CHARACTERIZATION OF BIETTI CRYSTALLINE DYSTROPHY IN DIFFERENT STAGES

      UTILIZATION OF FUNDUS AUTOFLUORESCENCE, SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY, AND ENHANCED DEPTH IMAGING IN THE CHARACTERIZATION OF BIETTI CRYSTALLINE DYSTROPHY IN DIFFERENT STAGES

      Purpose: To characterize Bietti crystalline dystrophy (BCD) in different stages using multiple imaging modalities. Methods: Sixteen participants clinically diagnosed as BCD were included in the retrospective study and were categorized into 3 stages according to fundus photography. Eleven patients were genetically confirmed. Fundus autofluorescence, spectral domain optical coherence tomography, and enhanced depth imaging features of BCD were analyzed. Results: On fundus autofluorescence, the abnormal autofluorescence was shown to enlarge in area and decrease in intensity with stages. Using spectral domain optical coherence tomography, the abnormalities in Stage 1 were observed to localize in outer retinal layers, whereas in Stage 2 ...

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    11. PEGylated Aucore–Agshell Nanorods as Optical Coherence Tomography Signal Nanoamplifiers

      PEGylated Aucore–Agshell Nanorods as Optical Coherence Tomography Signal Nanoamplifiers

      Optimizing contrast enhancement in optical coherence tomography (OCT) is essential for producing specific image signals and realizing its potential use in various biomedical imaging fields besides ophthalmology and cardiology. Using nanoparticles as selective signal nanoamplifiers will be helpful to highlight the lesion sites and identify cancerous changes that are difficult to diagnose currently. In this study, a quantitatively detailed analysis on the improvement of contrast enhancement and penetration depth of Au core –Ag shell nanorods (Au@Ag NRs) as OCT contrast agent was performed. The average A-scan data of the tissue was extracted and investigated. The signal to noise ratio ...

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    12. Feature Of The Week 9/26/10: Researchers from University of Maryland Demonstrated Multimodality Optical Coherence Tomography and Fluorescence Laminar Optical Tomography Imaging

      Feature Of The Week 9/26/10: Researchers from University of Maryland Demonstrated Multimodality Optical Coherence Tomography and Fluorescence Laminar Optical Tomography Imaging
      Feature Of The Week 9/26/10: Multimodal imaging represents one of the current trends in the development of biophotonics imaging technologies for the integration of molecular and physiological information with structural information, enabling in vivo visualization and quantification of disease biomarkers and their progression over time. Multimodal imaging therefore improves the understanding of disease development, enables early diagnosis, and ultimately enhances treatment efficacy. This work presents an integration of optical coherence tomography (OCT) and fluorescence laminar optical tomography (FLOT), which combines the advantages of high-resolution structural imaging from OCT with high-sensitivity functional imaging from FLOT. This platform provides contextual ...
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    13. Integrated Optical Coherence Tomography (OCT) and Fluorescence Laminar Optical Tomography (FLOT)

      Integrated Optical Coherence Tomography (OCT) and Fluorescence Laminar Optical Tomography (FLOT)
      Multimodal imaging represents one of the current trends in the development of biophotonics imaging technologies. This paper briefly reviews current multimodal biophotonics imaging platforms in macroscopic, microscopic, and mesoscopic (or millimeter) scales. We also present a combined optical coherence tomography and line-scan fluorescence laminar optical tomography system for co-registered structural and molecular imaging with millimeter-scale imaging depth. Experimental results using a capillary phantom filled with the fluorescence dye Cy5.5 and a human breast cancer xenograft model are presented.
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    14. Optical Coherence Tomography of Human Kidney

      Optical Coherence Tomography of Human Kidney
      Purpose To determine histopathological status of living human kidneys in real time and a noninvasive fashion would be a significant advancement in renal disease diagnosis. Recently we reported that optical coherence tomography has the requisite high spatial resolution to noninvasively determine histopathological changes in rodent kidneys with μm scale resolution. We established whether optical coherence tomography could 1) effectively penetrate the connective tissue capsule surrounding human kidneys, 2) provide a global survey of the human renal surface and 3) determine histopathological changes in human renal microstructure. Materials and Methods Using a high speed optical coherence tomography system equipped with a ...
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    15. Multi-modality optical tomography for simultaneous morphological and molecular imaging

      Optical coherence tomography (OCT) is an emerging medical imaging technology that can generate high resolution cross-sectional imaging (1-2 mm in depth) of tissue microstructure in situ and in real time. Fluorescence imaging provides tissue biochemical, metabolism, and molecular information by measuring fluorescence intensity or spectroscopy of either intrinsic fluorophores or exogenous contrast agents. The combination of these two modalities provides complementary morphological, functional and molecular information to comprehensively assess tissue status. There is a great interest to further extend the fluorescence imaging into tomography in order to provide depth-resolved molecular function that can be coregistered with 3-D tissue morphology provided ...
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    16. Feature Of The Week 9/6/09: Automated Quantification of Microstructural Dimensions of the Human Kidney using Optical Coherence Tomography

      Feature Of The Week 9/6/09: Automated Quantification of Microstructural Dimensions of the Human Kidney using Optical Coherence Tomography
      Feature Of The Week 9/6/09: Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can non-invasively provide cross-sectional, high-resolution images of tissue morphology in situ and in real-time. Recent development in high-speed OCT enables the acquisition of a large amount of three-dimensional image d
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    17. Automated quantification of microstructural dimensions of the human kidney using optical coherence tomography (OCT)

      Automated quantification of microstructural dimensions of the human kidney using optical coherence tomography (OCT)
      Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can non-invasively provide cross-sectional, highresolution images of tissue morphology in situ and in real-time. We previously demonstrated that OCT is capable of visualizing characteristic kidney anatomic structures, including blood vessels, uriniferous tubules,glomeruli, and renal capsules on a Munich–Wistar rat model. Because the viability of a donor kidney is closely correlated with its tubular morphology, and a large amount of image datasets are expected when using OCT to scan the entire kidney to provide a global assessment of its viability, it is necessary to develop automatic image analysis ...
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    18. Three-dimensional coregistered optical coherence tomography and line-scanning fluorescence laminar optical tomography

      Three-dimensional coregistered optical coherence tomography and line-scanning fluorescence laminar optical tomography
      We present a combined optical coherence tomography (OCT) and line-scanning fluorescence laminar optical tomography (FLOT) system. This hybrid system enables coregistered structural and molecular imaging in 3D with 10–100 um resolution and millimeter-scale imaging depth. Experimental results on a capillary phantom with fluorescence dye Cy5.5 using an OCT/FLOT imaging system have been demonstrated.
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    19. Combining optical coherence tomography with fluorescence molecular imaging: towards simultaneous morphology and molecular imaging

      Optical coherence tomography (OCT) provides high-resolution, cross-sectional imaging of tissue microstructure in situ and in real-time, while fluorescence molecular imaging (FMI) enables the visualization of basic molecular processes. There are great interests in combining these two modalities so that the tissue's structural and molecular information can be obtained simultaneously. This could greatly benefit biomedical applications such as detecting early diseases and monitoring therapeutic interventions. In this research, a new optical system that combines OCT and FMI was developed. The system demonstrated that it could co-register en face OCT and FMI images with a 2.4 x 2.4 mm ...
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    1-19 of 19
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    1. (8 articles) University of Maryland
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    Three-dimensional coregistered optical coherence tomography and line-scanning fluorescence laminar optical tomography Automated quantification of microstructural dimensions of the human kidney using optical coherence tomography (OCT) Feature Of The Week 9/6/09: Automated Quantification of Microstructural Dimensions of the Human Kidney using Optical Coherence Tomography Optical Coherence Tomography of Human Kidney Integrated Optical Coherence Tomography (OCT) and Fluorescence Laminar Optical Tomography (FLOT) Feature Of The Week 9/26/10: Researchers from University of Maryland Demonstrated Multimodality Optical Coherence Tomography and Fluorescence Laminar Optical Tomography Imaging PEGylated Aucore–Agshell Nanorods as Optical Coherence Tomography Signal Nanoamplifiers Dual band dual focus optical coherence tomography for imaging the whole eye segment Advances in bronchoscopic optical coherence tomography and confocal laser endomicroscopy in pulmonary diseases Morphologic Stages of Rhegmatogenous Retinal Detachment Assessed with Swept-Source Optical Coherence Tomography En Face Images Using Ultra-Widefield Optical Coherence Tomography in 2 Cases of Traumatic Hypotony Maculopathy before and after Surgical Intervention Clinical Course of OCTA en face Imaging Findings in a Patient with HELLP Syndrome