1. Articles from Jinyong Ha

    1-14 of 14
    1. Optical rotary junction incorporating a hollow shaft DC motor for high-speed catheter-based optical coherence tomography

      Optical rotary junction incorporating a hollow shaft DC motor for high-speed catheter-based optical coherence tomography

      In intravascular optical coherence tomography (OCT), the optical rotary junction plays an important role in rotating and pulling back the catheter to generate cross-sectional coronary artery images. To meet the requirements of high-speed intravascular OCT in a clinical setting, the rotary junction should generate high torque and low vibration. In this Letter, we demonstrate an ultrahigh speed optical rotary junction incorporating a hollow shaft brushless DC servomotor to remove a pulley belt, or a gear to minimize vibration noise and transfer stable torque. To evaluate the performance of the rotary junction, the vibration noise and variation of rotation were measured ...

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    2. Automated accurate lumen segmentation using L-mode interpolation for three-dimensional intravascular optical coherence tomography

      Automated accurate lumen segmentation using L-mode interpolation for three-dimensional intravascular optical coherence tomography

      Intravascular optical coherence tomography (IVOCT) lumen-based computational flow dynamics (CFD) enables physiologic evaluations such as of the fractional flow reserve (FFR) and wall sheer stress. In this study, we developed an accurate, time-efficient method for extracting lumen contours of the coronary artery. The contours of cross-sectional images containing wide intimal discontinuities due to guide wire shadowing and large bifurcations were delineated by utilizing the natural longitudinal lumen continuity of the arteries. Our algorithm was applied to 5931 pre-intervention OCT images acquired from 40 patients. For a quantitative comparison, the images were also processed through manual segmentation (the reference standard) and ...

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    3. Assessing Computational Fractional Flow Reserve From Optical Coherence Tomography in Patients With Intermediate Coronary Stenosis in the Left Anterior Descending Artery

      Assessing Computational Fractional Flow Reserve From Optical Coherence Tomography in Patients With Intermediate Coronary Stenosis in the Left Anterior Descending Artery

      Background— Intravascular optical coherence tomography (OCT) imaging provides limited information on the functional assessment of coronary stenosis. We evaluated a new approach to OCT image–based computation modeling, which can be used to estimate the fractional flow reserve (FFR) in patients with intermediate coronary stenosis. Methods and Results— Ninety-two patients with intermediate diameter stenosis in the left anterior descending artery underwent both FFR measurement with pressure wires and OCT examination. Using the OCT data, a computational fluid dynamics algorithm was used to calculate the computational FFR (FFR OCT ). The diagnostic performance of the FFR OCT was assessed based on the ...

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    4. Three-dimensional optical coherence tomographic analysis of eccentric morphology of the jailed side-branch ostium in coronary bifurcation lesions

      Three-dimensional optical coherence tomographic analysis of eccentric morphology of the jailed side-branch ostium in coronary bifurcation lesions

      Background The severity of angiographic diameter stenosis of the jailed side-branch ostium is usually overestimated over the three-dimensional (3D) optical coherence tomography (OCT)-measured actual stenosis. Using the 3D-OCT, morphologic changes in the jailed side-branch ostium were evaluated before and after a single stent crossover at coronary bifurcation lesions. Methods In 109 patients who received a single stent crossover at coronary bifurcation lesions, the pre- and post-intervention minimal lumen area (MLA) and the eccentricity of the jailed side-branch ostium were measured with 3D-OCT. The eccentricity index was defined as the ratio of maximal diameter/minimal diameter of the jailed side-branch ...

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    5. Eccentric morphology of jailed side-branch ostium after stent crossover in coronary bifurcation lesions: A three-dimensional optical coherence tomographic analysis

      Eccentric morphology of jailed side-branch ostium after stent crossover in coronary bifurcation lesions: A three-dimensional optical coherence tomographic analysis

      Background Angiographic stenosis of a jailed side-branch ostium is usually observed after a single-stent crossover at coronary bifurcation lesions. However, the stenosis severity is typically overestimated due to the limited information obtained from two-dimensional morphology by angiography. We evaluated the actual stenosis of jailed side-branch ostium using three-dimensional (3D) optical coherence tomography (OCT). Methods Using 3D reconstructions of OCT data, we analyzed minimal lumen area (MLA) and eccentricity of the jailed side-branch ostium in 41 patients who were treated with single stent crossover at coronary bifurcation lesions and subsequently underwent serial OCT follow-up. Results The MLA of jailed side-branch ostium ...

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    6. The Relationship Between Post-Stent Strut Apposition and Follow-Up Strut Coverage Assessed by a Contour Plot Optical Coherence Tomography Analysis

      The Relationship Between Post-Stent Strut Apposition and Follow-Up Strut Coverage Assessed by a Contour Plot Optical Coherence Tomography Analysis

      Objectives This study sought to evaluate the relationship between post-stent strut apposition and follow-up strut coverage using contour plot optical coherence tomographic analysis. Background Tracking the fate of interested regions of struts at different time points has not been investigated. Methods Post-intervention and 6-month follow-up optical coherence tomographic evaluations were performed in 82 patients treated with biolimus- (n = 37) or sirolimus-eluting stents (n = 45). Post-stent apposition was classified as embedded, apposed, or malapposed. For volumetric stent evaluation, the post-intervention strut-artery distance and the neointimal thickness at follow-up were measured as a function of the circumferential arc length and longitudinal stent ...

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    7. Randomised comparison of strut coverage between Nobori biolimus-eluting and sirolimus-eluting stents: an optical coherence tomography analysis

      Randomised comparison of strut coverage between Nobori biolimus-eluting and sirolimus-eluting stents: an optical coherence tomography analysis

      Aims: The aims of this study were to compare strut tissue coverage at six-month follow-up after Nobori biolimus-eluting stent (N-BES) versus sirolimus-eluting stent (SES) implantation. Methods and results: A total of 120 patients with a single stenotic lesion requiring revascularisation were randomly assigned to either N-BES (n=60) or SES (n=60). Baseline optical coherence tomography (OCT) was performed post stent implantation, and follow-up OCT was scheduled at six months. Post-intervention and follow-up OCT analyses were available in 51 (85.0%) and 52 (86.7%) patients, respectively. The primary endpoint was the percentage of uncovered struts at follow-up OCT in ...

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    8. System, method and computer-accessible medium for tracking vessel motion during three-dimensional coronary artery microscopy

      System, method and computer-accessible medium for tracking vessel motion during three-dimensional coronary artery microscopy

      Exemplary embodiments of apparatus, method and computer accessible medium can be provided which can facilitate a determination of at least one characteristic of a structure. For example, it is possible to use at least one first arrangement which can be structured to provide at least one first transmitted radiation along a first axis and at least one second transmitted radiation along a second axis. The first and second transmitted radiations can impact the structure and generate respective first and second returned radiation. The first and second axis can be provided at a predetermined angle with respect with one another which ...

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    9. Broadband wavelength swept source combining a quantum dot and a quantum well SOA in the wavelength range of 1153–1366 nm

      Broadband wavelength swept source combining a quantum dot and a quantum well SOA in the wavelength range of 1153–1366 nm

      wide tuning range wavelength swept laser for high axial resolution optical coherence tomography reported. Here, a parallel configuration of a quantum dot semiconductor optical amplifier (SOA) and a quantum well SOA is utilised for broadband optical source. The total scanning range of over 210 nm (192 nm at 10 dB) from 1153 to 1366 nm is reported. To investigate the feasiblity of the swept light source, demonstrated is an optical frequency domain imaging (OFDI) system. The system sensitivity of 101 dB is reported and axial resolution of 6.0 µm in air is achieved. Finally, ex vivo OFDI imaging of ...

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      Mentions: Samsung
    10. Neointimal patterns obtained by optical coherence tomography correlate with specific histological components and neointimal proliferation in a swine model of restenosis

      Neointimal patterns obtained by optical coherence tomography correlate with specific histological components and neointimal proliferation in a swine model of restenosis

      Aims Although optical coherence tomography (OCT) is capable to detect microscopic peri-strut changes that seem to be related to neointimal inhibition and healing, its ability to characterize these components is still limited. In this study, we aimed to compare different OCT morphological characteristics with different in-stent neointimal tissue types analysed by histology. Methods A total of 69 stents (39 drug eluting and 30 bare metal stents) were implanted in coronary arteries of 27 swine. By OCT, neointimal type was classified as homogeneous, heterogeneous, or layered according to its pattern of backscatter and optical intensity. The resulting optical patterns were correlated ...

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    11. Feature Of The Week 3/3/13: Complex wavefront shaping for optimal depth-selective focusing in optical coherence tomography

      Feature Of The Week 3/3/13: Complex wavefront shaping for optimal depth-selective focusing in optical coherence tomography

      We present that a novel wavefront shaping approach improves the penetration depth and sensitivity of optical coherence tomography (OCT) by systematically control multiple light scattering. As well known, the penetration depth of OCT is significantly limited due to multiple light scattering that is resulted from refractive inhomogeneity. Whereas OCT can achieve satisfactory penetration depth in ophthalmology where the tissue structures are relatively transparent (weakly turbid), the limited penetration depth of OCT prevents general applications to other highly turbid opaque tissues such as skin tissue. Conventional approaches to attempt to solve this issue in OCT have revealed challenges in dealing with ...

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    12. Complex wavefront shaping for optimal depth-selective focusing in optical coherence tomography

      Complex wavefront shaping for optimal depth-selective focusing in optical coherence tomography

      We report on an approach to exploit multiple light scattering by shaping the incident wavefront in optical coherence tomography (OCT). Most of the reflected signal from biological tissue consists of multiply scattered light, which is regarded as noise in OCT. A digital mirror device (DMD) is utilized to shape the incident wavefront such that the maximal energy is focused at a specific depth in a highly scattering sample using a coherence-gated reflectance signal as feedback. The proof-of-concept experiment demonstrates that this approach enhances depth-selective focusing in the presence of optical inhomogeneity, and thus extends the penetration depth in spectral domain-OCT ...

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    13. Compensation of motion artifacts in intracoronary optical frequency domain imaging and optical coherence tomography

      Compensation of motion artifacts in intracoronary optical frequency domain imaging and optical coherence tomography

      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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    1-14 of 14
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  2. Topics in the News

    1. (8 articles) Yonsei University
    2. (7 articles) Jung-Sun Kim
    3. (6 articles) Yangsoo Jang
    4. (6 articles) Myeong-Ki Hong
    5. (6 articles) Young-Guk Ko
    6. (6 articles) Dong Hoon Choi
    7. (3 articles) Samsung
    8. (3 articles) Cardiovascular Research Foundation
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    10. (2 articles) Brett E. Bouma
    11. (1 articles) Medical University of Vienna
    12. (1 articles) Harbin Medical University
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    Compensation of motion artifacts in intracoronary optical frequency domain imaging and optical coherence tomography Assessing Neointimal Coverage After DES Implantation by 3D OCT Complex wavefront shaping for optimal depth-selective focusing in optical coherence tomography Feature Of The Week 3/3/13: Complex wavefront shaping for optimal depth-selective focusing in optical coherence tomography Neointimal patterns obtained by optical coherence tomography correlate with specific histological components and neointimal proliferation in a swine model of restenosis Broadband wavelength swept source combining a quantum dot and a quantum well SOA in the wavelength range of 1153–1366 nm System, method and computer-accessible medium for tracking vessel motion during three-dimensional coronary artery microscopy Randomised comparison of strut coverage between Nobori biolimus-eluting and sirolimus-eluting stents: an optical coherence tomography analysis The Relationship Between Post-Stent Strut Apposition and Follow-Up Strut Coverage Assessed by a Contour Plot Optical Coherence Tomography Analysis Eccentric morphology of jailed side-branch ostium after stent crossover in coronary bifurcation lesions: A three-dimensional optical coherence tomographic analysis Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age Direct en-face, speckle-reduced images using angular-compounded Master-Slave optical coherence tomography