1. Articles from Min Woo Lee

    1-14 of 14
    1. Comprehensive Assessment of High-Risk Plaques by Dual-Modal Imaging Catheter in Coronary Artery

      Comprehensive Assessment of High-Risk Plaques by Dual-Modal Imaging Catheter in Coronary Artery

      Coronary plaque destabilization involves alterations in microstructure and biochemical composition; however, no imaging approach allows such comprehensive characterization. Herein, the authors demonstrated a simultaneous microstructural and biochemical assessment of high-risk plaques in the coronary arteries in a beating heart using a fully integrated optical coherence tomography and fluorescence lifetime imaging (FLIm). It was found that plaque components such as lipids, macrophages, lipids+macrophages, and fibrotic tissues had unique fluorescence lifetime signatures that were distinguishable using multispectral FLIm. Because FLIm yielded massive biochemical readouts, the authors incorporated machine learning framework into FLIm, and ultimately, their approach enabled an automated, quantitative imaging ...

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    2. In Vivo Cellular-Level 3D Imaging of Peripheral Nerves Using a Dual-Focusing Technique for Intra-Neural Interface Implantation

      In Vivo Cellular-Level 3D Imaging of Peripheral Nerves Using a Dual-Focusing Technique for Intra-Neural Interface Implantation

      In vivo volumetric imaging of the microstructural changes of peripheral nerves with an inserted electrode could be key for solving the chronic implantation failure of an intra-neural interface necessary to provide amputated patients with natural motion and sensation. Thus far, no imaging devices can provide a cellular-level three-dimensional (3D) structural images of a peripheral nerve in vivo. In this study, an optical coherence tomography-based peripheral nerve imaging platform that employs a newly proposed depth of focus extension technique is reported. A point spread function with the finest transverse resolution of 1.27 µm enables the cellular-level volumetric visualization of the ...

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    3. Repeatability of Optical Coherence Tomography Angiography Measurements in Patients with Retinal Vein Occlusion

      Repeatability of Optical Coherence Tomography Angiography Measurements in Patients with Retinal Vein Occlusion

      Purpose: To analyze the repeatability of vessel density (VD) measurements and manual foveal avascular zone (FAZ) measure-ments using optical coherence tomography angiography (OCTA) in patients with retinal vein occlusion (RVO) without macular edema.Methods: The study population consisted of patients with RVO and central macular thickness <300 μm. For each subject, measurements were performed twice with a 5-minute interval. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated to analyze the repeatability of results obtained with the OCTA device. To identify factors relat-ed to repeatability, we performed Pearson correlation analyses based on the CV of potential factors ...

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    4. Astigmatism-corrected endoscopic imaging probe for optical coherence tomography using soft lithography

      Astigmatism-corrected endoscopic imaging probe for optical coherence tomography using soft lithography

      In endoscopic optical coherence tomography, a transparent protective sheath is used to protect the optics and tissue. However, the sheath causes astigmatism, which degrades transverse resolution and signal-to-noise ratio due to the cylindrical lens effect. Generally used methods for correcting this astigmatism are complex, difficult to control precisely, high-cost, and increase the dimensions of the imaging probe. To overcome these problems, we have developed an astigmatism-corrected imaging probe with an epoxy window. The astigmatism is precisely and cost-effectively adjusted controlling the curvature radius of the epoxy window, which is produced by soft lithography. Using the fiber optic fusion splicing, the ...

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    5. A comparison of choroidal thicknesses between pachychoroid and normochoroid eyes acquired from wide‐field swept‐source OCT

      A comparison of choroidal thicknesses between pachychoroid and normochoroid eyes acquired from wide‐field swept‐source OCT

      Purpose We investigated the wide‐field choroidal thickness (CT) using swept‐source optical coherence tomography (SS‐OCT) and compared the characteristics of the choroidal layer between pachychoroid and normochoroid groups. Methods A total of 120 eyes from 120 normal subjects were included. All subjects were divided into two groups according to the subfoveal CT (≥300 μm, pachychoroid group; <300μm, normochoroid group). All subjects underwent an HD spotlight 16 mm scan using SS‐OCT. The CT was measured at the following 12 points: subfoveal, 3 points in the nasal peripapillary area, 6 points in the macular area and 2 peripheral ...

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    6. Flexible endoscopic micro-optical coherence tomography for three-dimensional imaging of the arterial microstructure

      Flexible endoscopic micro-optical coherence tomography for three-dimensional imaging of the arterial microstructure

      Micro-optical coherence tomography (µOCT) is a novel imaging approach enabling visualization of the microstructures of biological tissues at a cellular or sub-cellular level. However, it has been challenging to develop a miniaturized flexible endoscopic µOCT probe allowing helical luminal scanning. In this study, we built a flexible endoscopic µOCT probe with an outer diameter of 1.2 mm, which acquires three-dimensional images of the arterial microstructures via helical scanning with an axial and lateral resolutions of 1.83 µm and 3.38 µm in air, respectively. Furthermore, the depth of focus of the µOCT imaging probe was extended two-fold using ...

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    7. Repeatability of Manual Measurement of Foveal Avascular Zone Area in Optical Coherence Tomography Angiography Images in High Myopia

      Repeatability of Manual Measurement of Foveal Avascular Zone Area in Optical Coherence Tomography Angiography Images in High Myopia

      Purpose To analyze the repeatability of manual measurement of foveal avascular zone (FAZ) area in an optical coherence tomography angiography (OCTA) image in high myopia. Methods This study comprised patients with high myopia and controls. Two consecutive FAZ areas of the superficial and deep capillary plexus were obtained using OCTA. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were assessed, and univariate and multivariate generalized linear mixed models were conducted to identify factors related to repeatability. Results Thirty eyes with high myopia and 34 eyes of healthy subjects were included in the study. The mean age in high ...

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    8. Interocular Symmetry of Optical Coherence Tomography Angiography Parameters in Normal Eyes of Korean Adults

      Interocular Symmetry of Optical Coherence Tomography Angiography Parameters in Normal Eyes of Korean Adults

      Purpose To evaluate the interocular symmetry of microvascular parameters measured by optical coherence tomography angiography (OCTA) in normal eyes of Korean adults. Methods We retrospectively reviewed the retinal microvascular structure of 91 healthy Korean subjects (182 eyes). We used OCTA to measure the area of the foveal avascular zone (FAZ), vessel density (VD), and perfusion density (PD) in both eyes. Intraclass correlation coefficients (ICCs), coefficients of variation (CVs), and Pearson correlation coefficients were calculated to evaluate the extent of agreement and correlations between binocular OCTA measurements. Results Both eyes had similar microvascular characteristics: FAZ area (right eye: 0.31 ± 0 ...

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    9. Associations Between Individual Retinal Layer Thicknesses And Diabetic Peripheral Neuropathy Using Retinal Layer Segmentation Analysis

      Associations Between Individual Retinal Layer Thicknesses And Diabetic Peripheral Neuropathy Using Retinal Layer Segmentation Analysis

      Purpose: To evaluate clinical correlations between the thicknesses of individual retinal layers in the foveal area of diabetic patients and the presence of diabetic peripheral neuropathy (DPN). Methods: This retrospective, observational, cross-sectional study enrolled a total of 120 eyes from 120 patients. The eyes were divided into 3 groups: normal controls (n = 42 eyes), patients with diabetes mellitus (n = 42 eyes) but no DPN, and patients with diabetes mellitus and DPN (n = 36 eyes). The primary outcome measures were the thickness of all retinal layers in the central 1-mm zone measured using the segmentation analysis of spectral-domain optical coherence tomography ...

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    10. Comprehensive intravascular imaging of atherosclerotic plaque in vivo using optical coherence tomography and fluorescence lifetime imaging

      Comprehensive intravascular imaging of atherosclerotic plaque in vivo using optical coherence tomography and fluorescence lifetime imaging

      Comprehensive imaging of both the structural and biochemical characteristics of atherosclerotic plaque is essential for the diagnosis and study of coronary artery disease because both a plaque’s morphology and its biochemical composition affect the level of risk it poses. Optical coherence tomography (OCT) and fluorescence lifetime imaging (FLIm) are promising optical imaging methods for characterizing coronary artery plaques morphologically and biochemically, respectively. In this study, we present a hybrid intravascular imaging device, including a custom-built OCT/FLIm system, a hybrid optical rotary joint, and an imaging catheter, to visualize the structure and biochemical composition of the plaque in an ...

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    11. Multispectral analog-mean-delay fluorescence lifetime imaging combined with optical coherence tomography

      Multispectral analog-mean-delay fluorescence lifetime imaging combined with optical coherence tomography

      The pathophysiological progression of chronic diseases, including atherosclerosis and cancer, is closely related to compositional changes in biological tissues containing endogenous fluorophores such as collagen, elastin, and NADH, which exhibit strong autofluorescence under ultraviolet excitation. Fluorescence lifetime imaging (FLIm) provides robust detection of the compositional changes by measuring fluorescence lifetime, which is an inherent property of a fluorophore. In this paper, we present a dual-modality system combining a multispectral analog-mean-delay (AMD) FLIm and a high-speed swept-source optical coherence tomography (OCT) to simultaneously visualize the cross-sectional morphology and biochemical compositional information of a biological tissue. Experiments using standard fluorescent solutions showed ...

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    12. Intracoronary dual-modal optical coherence tomography-near-infrared fluorescence structural–molecular imaging with a clinical dose of indocyanine green for the assessment of high-risk plaques and stent-associated inflammation in a beating coronary artery

      Intracoronary dual-modal optical coherence tomography-near-infrared fluorescence structural–molecular imaging with a clinical dose of indocyanine green for the assessment of high-risk plaques and stent-associated inflammation in a beating coronary artery

      Aims Inflammation plays essential role in development of plaque disruption and coronary stent-associated complications. This study aimed to examine whether intracoronary dual-modal optical coherence tomography (OCT)-near-infrared fluorescence (NIRF) structural–molecular imaging with indocyanine green (ICG) can estimate inflammation in swine coronary artery. Methods and results After administration of clinically approved NIRF-enhancing ICG (2.0 mg/kg) or saline, rapid coronary imaging (20 mm/s pullback speed) using a fully integrated OCT-NIRF catheter was safely performed in 12 atheromatous Yucatan minipigs and in 7 drug-eluting stent (DES)-implanted Yorkshire pigs. Stronger NIRF activity was identified in OCT-proven high-risk plaque compared ...

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    13. Feature Of The Week 8/31/14: Fully Integrated High-speed Intravascular OCT/NIRF Structural/Molecular Imaging In Vivo using a Clinically-available NIRF Emitting Indocyanine Green to Detect Inflamed Lipid-rich Atheromata in Coronary-sized Vessels

      Feature Of The Week 8/31/14: Fully Integrated High-speed Intravascular OCT/NIRF Structural/Molecular Imaging In Vivo using a Clinically-available NIRF Emitting Indocyanine Green to Detect Inflamed Lipid-rich Atheromata in Coronary-sized Vessels

      In current study, we fully integrated near-infrared fluorescence (NIRF) molecular imaging into intravascular OCT structural imaging. The OCT/NIRF single catheter imaging clearly demonstrated the microstructure of atheromata and simultaneously identified ICG-enhancing macrophage abundant lipid-rich areas of the plaques. Ex vivo NIRF imaging evidently validated in vivo OCT-NIRF imaging. NIRF signals on ex vivo fluorescence reflectance imaging colocalized well with in vivo NIRF imaging. In vitro ICG cell uptake, correlative fluorescence microscopy, and histopathology corroborated the in vivo imaging findings. Herein, our research team have solved the issues critical for application of this OCT/NIRF imaging technology to clinical practice ...

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    14. Fully Integrated High-Speed Intravascular OCT/NIRF Structural/Molecular Imaging In Vivo Using a Clinically Available Near-Infrared Fluorescence–Emitting Indocyanine Green to Detect Inflamed Lipid-Rich Atheromata in Coronary-Sized Vessels

      Fully Integrated High-Speed Intravascular OCT/NIRF Structural/Molecular Imaging In Vivo Using a Clinically Available Near-Infrared Fluorescence–Emitting Indocyanine Green to Detect Inflamed Lipid-Rich Atheromata in Coronary-Sized Vessels

      Background— Lipid-rich inflamed coronary plaques a reprone to rupture. The purpose of this study was to assess lipid-rich inflamed plaques invivo using fully integrated high-speed optical coherence tomography (OCT)/ near-infrared fluorescence (NIRF) molecular imaging with a Food and Drug Administration– a pproved indocyanine green (ICG). Methods a nd Results— A n integrated high-speed intravascular OCT/NIRF imaging c a theter a nd a du a l-mod a l OCT/NIRF system were constructed b a sed on a cl in ic a l OCT pl a tform. For imaging lipid-rich inflamed plaques, the Food and Drug Administration– approved NIRF-emitting ICG ...

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    1-14 of 14
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    1. (9 articles) Korea Advanced Institute of Science and Technology
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    Fully Integrated High-Speed Intravascular OCT/NIRF Structural/Molecular Imaging In Vivo Using a Clinically Available Near-Infrared Fluorescence–Emitting Indocyanine Green to Detect Inflamed Lipid-Rich Atheromata in Coronary-Sized Vessels Feature Of The Week 8/31/14: Fully Integrated High-speed Intravascular OCT/NIRF Structural/Molecular Imaging In Vivo using a Clinically-available NIRF Emitting Indocyanine Green to Detect Inflamed Lipid-rich Atheromata in Coronary-sized Vessels Intracoronary dual-modal optical coherence tomography-near-infrared fluorescence structural–molecular imaging with a clinical dose of indocyanine green for the assessment of high-risk plaques and stent-associated inflammation in a beating coronary artery Multispectral analog-mean-delay fluorescence lifetime imaging combined with optical coherence tomography Comprehensive intravascular imaging of atherosclerotic plaque in vivo using optical coherence tomography and fluorescence lifetime imaging Associations Between Individual Retinal Layer Thicknesses And Diabetic Peripheral Neuropathy Using Retinal Layer Segmentation Analysis Interocular Symmetry of Optical Coherence Tomography Angiography Parameters in Normal Eyes of Korean Adults Repeatability of Manual Measurement of Foveal Avascular Zone Area in Optical Coherence Tomography Angiography Images in High Myopia Flexible endoscopic micro-optical coherence tomography for three-dimensional imaging of the arterial microstructure Astigmatism-corrected endoscopic imaging probe for optical coherence tomography using soft lithography Association of retinal thickness and microvasculature with cognitive performance and brain volumes in elderly adults A Deep Learning Framework for the Detection and Quantification of Reticular Pseudodrusen and Drusen on Optical Coherence Tomography