All Articles from Hongki Yoo -Optical Coherence Tomography News

Articles from Hongki Yoo

1-18 of 18
1. Flexible endoscopic micro-optical coherence tomography for three-dimensional imaging of the arterial microstructure
  
  Explore Nature Publishing Group Jun 10 2020 Cardiology , Probes
  
  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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  Mentions: Korea University Korea Advanced Institute of Science and Technology Hongki Yoo
2. Comprehensive intravascular imaging of atherosclerotic plaque in vivo using optical coherence tomography and fluorescence lifetime imaging
  
  Explore Nature Publishing Group Oct 2 2018 Cardiology
  
  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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  Mentions: Wang Yuhl Oh Hanyang University Korea University
3. Multispectral analog-mean-delay fluorescence lifetime imaging combined with optical coherence tomography
  
  Explore OSA | OSA Publishing Apr 16 2018
  
  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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  Mentions: Wang Yuhl Oh Hanyang University Korea University
4. Endoscopic micro-optical coherence tomography with extended depth of focus using a binary phase spatial filter
  
  Explore OSA | OSA Publishing Jan 20 2017 Gastroenterology , Probes
  
  Micro-optical coherence tomography (μOCT) is an advanced imaging technique that acquires a three-dimensional microstructure of biological samples with a high spatial resolution, up to 1 μm, by using a broadband light source and a high numerical aperture (NA) lens. As high NA produces a short depth of focus (DOF), extending the DOF is necessary to obtain a reasonable imaging depth. However, due to the complexity of optics and the limited space, it has been challenging to fabricate endoscopic μOCT, which is essential for clinical translation. Here, we report an endoscopic μOCT probe with an extended DOF by using a binary ...
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  Mentions: Hanyang University Jin Won Kim Hongki Yoo
5. Characterization of lipid-rich plaques using spectroscopic optical coherence tomography
  
  Explore SPIE | Journal Jul 9 2016 Cardiology
  
  Intravascular optical coherence tomography (IV-OCT) is a high-resolution imaging method used to visualize the internal structures of walls of coronary arteries in vivo . However, accurate characterization of atherosclerotic plaques with gray-scale IV-OCT images is often limited by various intrinsic artifacts. In this study, we present an algorithm for characterizing lipid-rich plaques with a spectroscopic OCT technique based on a Gaussian center of mass (GCOM) metric. The GCOM metric, which reflects the absorbance properties of lipids, was validated using a lipid phantom. In addition, the proposed characterization method was successfully demonstrated in vivo using an atherosclerotic rabbit model and was found ...
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  Mentions: Wang Yuhl Oh Hanyang University Korea University
6. Automated detection of vessel lumen and stent struts in intravascular optical coherence tomography to evaluate stent apposition and neointimal coverage
  
  Explore Scitation Mar 1 2016 Cardiology
  
  Purpose: Intravascular optical coherence tomography (IV-OCT) is a high-resolution imaging method used to visualize the microstructure of arterial walls in vivo . IV-OCT enables the clinician to clearly observe and accurately measure stent apposition and neointimal coverage of coronary stents, which are associated with side effects such as in-stent thrombosis. In this study, the authors present an algorithm for quantifying stent apposition and neointimal coverage by automatically detecting lumen contours and stent struts in IV-OCT images. Methods: The algorithm utilizes OCT intensity images and their first and second gradient images along the axial direction to detect lumen contours and stent strut ...
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  Mentions: Hanyang University Korea University Jin Won Kim
7. 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
  
  Explore Oxford Journals Jan 21 2016 Cardiology
  
  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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  Mentions: Wang Yuhl Oh Hanyang University Korea University
8. Design and fabrication of an optical probe with a phase filter for extended depth of focus
  
  Explore OSA | OSA Publishing Jan 18 2016 Probes
  
  The trade-off between spot size and depth of focus (DOF) often limits the performance of optical systems, such as optical coherence tomography and optical tweezers. Although researchers have proposed various methods to extend the DOF in free-space optics, many are difficult to implement in miniaturized optical probes due to space limitations. In this study, we present an optical probe with an extended DOF using a binary phase spatial filter (BPSF). The BPSF pattern was fabricated on the distal tip of an optical probe with a diameter of 1 mm by replica molding soft lithography, which can be easily implemented in ...
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  Mentions: Hanyang University Hongki Yoo
9. A bi-directional assessment of spontaneous coronary artery dissection by three-dimensional flythrough rending of optical coherence tomography images
  
  Explore Oxford Journals Jan 5 2015 Cardiology
  
  A 71-year-old woman was admitted to our hospital due to unstable chest pain. Coronary angiography demonstrated a complex eccentric lesion with 80% narrowing of the right coronary arterial lumen ( Panel A ). Intravascular optical coherence tomography (IV-OCT) revealed typical characteristics of spontaneous coronary artery...
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  Mentions: Hanyang University Korea University Jin Won Kim
10. 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
  
  Explore Optical Coherence Tomography News Aug 31 2014 Cardiology
  
  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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  Mentions: Wang Yuhl Oh FDA Hanyang University
11. 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
  
  Explore Circulation Jul 31 2014 Cardiology
  
  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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  Mentions: Wang Yuhl Oh FDA Hanyang University
12. Three-dimensional intravascular optical coherence tomography rendering assessment of spontaneous coronary artery dissection concomitant with left main ostial critical stenosis
  
  Explore ScienceDirect Jun 22 2014 Cardiology
  
  Images in Intervention
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  Mentions: Abbot Hanyang University Korea University
13. Coronary Stent Fracture Complicated Multiple Aneurysms Confirmed by 3-Dimensional Reconstruction of Intravascular-Optical Coherence Tomography in a Patient Treated With Open-Cell Designed Drug-Eluting Stent
  
  Explore Circulation Jan 20 2014 Cardiology
  
  A 55-year-old man with a previous history of cerebral infarct and hypertension presented to our cardiovascular center complaining of angina in November 2011. Chronic total occlusion in the proximal left anterior descending artery was identified by coronary angiography (Figure 1A). The patient subsequently underwent percutaneous coronary intervention. Wiring was done successfully with a tapered stiff wire (Conquest Pro 20; ASAHI INTECC). After multiple predilation, a single drug-eluting stent (3.0 × 18 mm) of an open-cell design and bioabsorbable polymer (Nobori; Terumo, Tokyo, Japan) was implanted using a 3.5-mm noncompliant balloon (inflation pressure, 24 atmospheric pressure; Quantum Maverick Balloon; Boston ...
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  Mentions: Terumo Corporation Boston Scientific Hanyang University
14. Evaluation of optical reflectance techniques for imaging of alveolar structure
  
  Explore Linking to Scitation Content Jun 11 2012 Pulmonology
  
  Three-dimensional (3-D) visualization of the fine structures within the lung parenchyma could advance our understanding of alveolar physiology and pathophysiology. Current knowledge has been primarily based on histology, but it is a destructive two-dimensional (2-D) technique that is limited by tissue processing artifacts. Micro-CT provides high-resolution three-dimensional (3-D) imaging within a limited sample size, but is not applicable to intact lungs from larger animals or humans. Optical reflectance techniques offer the promise to visualize alveolar regions of the large animal or human lung with sub-cellular resolution in three dimensions. Here, we present the capabilities of three optical reflectance techniques, namely ...
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  Mentions: Guillermo J. Tearney Brett E. Bouma Massachusetts Institute of Technology
15. Optical frequency domain imaging system and catheters for volumetric imaging of the human esophagus
  
  Explore Photonics Society of Poland Dec 29 2011 Gastroenterology , Oncology
  
  Barrett's esophagus (BE) is a metaplastic disorder that can undergo dysplastic progression, leading to esophageal adenocarcinoma. Upper endoscopy is the standard of care for screening for BE, but this technique has a relatively low diagnostic accuracy and high cost due to the requirement of conscious sedation. Optical frequency domain imaging (OFDI) is a high-speed imaging modality that generates cross-sectional images of tissues with a resolution of approximately 10µm that is sufficient for detecting microscopic tissue architecture. In combination with a balloon-centering catheter, this method enables BE diagnosis over the entire distal esophagus. Full Text: PDFReferences S. H. Yun ...
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  Mentions: Guillermo J. Tearney Brett E. Bouma Massachusetts Institute of Technology
16. Intra-arterial catheter for simultaneous microstructural and molecular imaging in vivo
  
  Explore Nature Publishing Group Nov 6 2011 Cardiology
  
  Advancing understanding of human coronary artery disease requires new methods that can be used in patients for studying atherosclerotic plaque microstructure in relation to the molecular mechanisms that underlie its initiation, progression and clinical complications, including myocardial infarction and sudden cardiac death. Here we report a dual-modality intra-arterial catheter for simultaneous microstructural and molecular imaging in vivo using a combination of optical frequency domain imaging (OFDI) and near-infrared fluorescence (NIRF) imaging. By providing simultaneous molecular information in the context of the surrounding tissue microstructure, this new catheter could provide new opportunities for investigating coronary atherosclerosis and stent healing and for ...
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  Mentions: Guillermo J. Tearney Brett E. Bouma Massachusetts Institute of Technology
17. Compensation of motion artifacts in intracoronary optical frequency domain imaging and optical coherence tomography
  
  Explore SpringerLink Home Oct 13 2011 Cardiology
  
  Abstract Intracoronary optical coherence tomography and optical frequency domain imaging (OFDI) have been utilized for two-dimensional and three-dimensional imaging of vascular microanatomy. Image quality and the spatial accuracy of multidimensional reconstructions, however, can be degraded due to artifacts resulting from relative motion between the intracoronary catheter and the vessel wall. To track the relative motion of a catheter with regard to the vessel, a motion tracking system was incorporated with a standard OFDI system by using wavelength division multiplexing techniques. Motion of the vessel was acquired by a frequency shift of the backscattered light caused by the Doppler effect. A ...
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  Mentions: Guillermo J. Tearney Brett E. Bouma Massachusetts General Hospital
18. Barrett's Esophagus Screening Using Balloon-Based Optical Frequency Domain Imaging: A Comparison With Endoscopy
  
  Explore Gastrointestinal Endoscopy Mar 31 2010 Gastroenterology
  
  Abstracts submitted to ASGE 2010. Optical coherence tomography (OCT) is a high-resolution cross-sectional imaging modality that has been shown to accurately differentiate esophageal pathology relevant to screening and surveillance in Barrett's patients. We have previously demonstrated that optical frequency domain imaging (OFDI), a high speed 2nd generation embodiment of OCT, may be used to perform volumetric microscopy of the distal esophagus in patients. In this present study we compare the sensitivity of OFDI to endoscopy for the diagnosis of specialized intestinal metaplasia (SIM), using histopathology as the gold standard.
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  Mentions: Guillermo J. Tearney Brett E. Bouma Massachusetts General Hospital
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