1. Articles from Tianshi Wang

    1-14 of 14
    1. Feature Of The Week 09/10/2017: Thermo-elastic Optical Coherence Tomography

      Feature Of The Week 09/10/2017: Thermo-elastic  Optical Coherence Tomography

      The conventional OCT image contrast is derived from elastic scattering, and shows the internal structure of the sample. The determination of the tissue type in OCT images usually depends on the interpretation by the image reader. More accurate tissue type contrast may be achieved by new OCT-based imaging modalities, with sensitivity to other physical parameters than scattering alone. Phase-sensitive OCT can detect tissue motion on nanometer-to- micrometer length scales using the phase of the OCT signal. Depending on the nature of the excitation, different functional images can be reconstructed: a mechanical stimulus yields images of tissue elasticity (optical coherence elastography ...

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    2. Thermo-elastic optical coherence tomography

      Thermo-elastic optical coherence tomography

      The absorption of nanosecond laser pulses induces rapid thermo-elastic deformation in tissue. A sub-micrometer scale displacement occurs within a few microseconds after the pulse arrival. In this Letter, we investigate the laser-induced thermo-elastic deformation using a 1.5 MHz phase-sensitive optical coherence tomography (OCT) system. A displacement image can be reconstructed, which enables a new modality of phase-sensitive OCT, called thermo-elastic OCT. An analysis of the results shows that the optical absorption is a dominating factor for the displacement. Thermo-elastic OCT is capable of visualizing inclusions that do not appear on the structural OCT image, providing additional tissue type information.

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    3. Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy

      Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy

      Intravascular optical coherence tomography (IV-OCT) has gained widespread use over the past few years, offering highly detailed images of coronary artery pathologies and interventions (1) . In contrast to the cross-sectional view, longitudinal sections and 3-dimensional (3D) renderings are affected by cardiac motion artifacts and undersampling, complicating interpretation and measurements (2) . We developed Heartbeat OCT, a new OCT method that achieves up to 4,000 frames/s imaging speed for isotropically sampled volume datasets acquired within the diastolic phase of 1 cardiac cycle to restore 3D IV-OCT image fidelity. In this research letter, we present the first in vivo data acquired ...

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    4. Heartbeat Optical Coherence Tomography (Thesis)

      Heartbeat Optical Coherence Tomography (Thesis)

      Coronary artery disease (CAD) is a manifestation of atherosclerosis, a systemic inflammatory disease of the arteries that causes the formation of plaques in the artery walls. Different plaques may give rise to different symptoms: a gradual narrowing (stenosis) of the vessel by growth of a fibrous or calcific plaque will cause chest pain (due to cardiac ischemia) upon exertion, a condition called stable CAD. Sudden onset of chest pain, or chest pain at rest, is a symptom of unstable CAD or acute coronary syndrome (ACS), which is associated with thrombus formation on plaques, mostly due to rupture of a lipid-core ...

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    5. Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography

      Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography

      Intravascular optical coherence tomography (IV-OCT) has gained widespread use over the past few years, offering highly detailed images of the coronary artery pathologies and interventions. In contrast to the cross-sectional view, longitudinal sections and three-dimensional (3D) renderings are affected by cardiac motion artifacts and undersampling, complicating interpretation and measurements. We developed Heartbeat OCT, a new OCT method that overcomes these issues. This study aims to demonstrate in vivo Heartbeat OCT in a preclinical setting, imaging eliminating cardiac motion artifacts, undersampling and non-uniform rotational distortion, to generate high-quality OCT volumes. Using a micro motor actuated catheter and a MHz sweep rate ...

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    6. Heartbeat OCT: in vivo intravascular megahertz-optical coherence tomography

      Heartbeat OCT: in vivo intravascular megahertz-optical coherence tomography

      Cardiac motion artifacts, non-uniform rotational distortion and undersampling affect the image quality and the diagnostic impact of intravascular optical coherence tomography (IV-OCT). In this study we demonstrate how these limitations of IV-OCT can be addressed by using an imaging system that we called “Heartbeat OCT”, combining a fast Fourier Domain Mode Locked laser, fast pullback, and a micromotor actuated catheter, designed to examine a coronary vessel in less than one cardiac cycle. We acquired in vivo data sets of two coronary arteries in a porcine heart with both Heartbeat OCT, working at 2.88 MHz A-line rate, 4000 frames/s ...

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    7. A Micromotor Catheter for Intravascular Optical Coherence Tomography

      A Micromotor Catheter for Intravascular Optical Coherence Tomography

      We have developed a new form of intravascular optical coherence tomography (IV-OCT) that allows the extremely fast acquisition of high-resolution images of the coronary arteries. This process leads to much better image quality by eliminating cardiac motion artefacts and undersampling. It relies on a catheter that incorporates a synchronous micromotor with a diameter of 1.0 mm and a rotational speed of up to 5600 revolutions per second, enabling an IV-OCT frame rate of 5.6 kHz. This speed is matched by a wavelength-swept laser that generates up to 2.8 million image lines per second. With this setup, our ...

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    8. Feature Of The Week 6/30/13: Ultrafast Intravascular Optical Coherence Tomography Imaging

      Feature Of The Week 6/30/13: Ultrafast Intravascular Optical Coherence Tomography Imaging

      The fastest commercial intravascular optical coherence tomography (OCT) systems acquire 160 frames/second with 500 lines/frame, and the pullback speed is limited to 40 mm∕s. In this situation, the images are under sampled in the pullback direction: Only 12% of the lumen is sampled because the sampling interval of 250 μm is much larger than the transverse resolution, which is approximately 30 μm. In clinical situations, the cardiac motion also affects the OCT acquisition. The pullback procedure for the whole artery takes several seconds. The cardiac motion during acquisition will cause inaccuracy in frame spacing and possibly frame ...

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    9. Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second

      Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second

      We demonstrated intravascular OCT imaging with frame rate up to 3.2 kHz (192,000 rpm scanning). This was achieved by using a custom-built catheter in which the circumferential scanning was actuated by a 1.0 mm diameter synchronous motor. The OCT system was based on a Fourier Domain Mode Locked laser operating at an A-line rate of 1.6 MHz. The diameter of the catheter was 1.1 mm at the tip. Ex vivo images of human coronary artery (~78.4 mm length) were acquired at a pullback speed of 100 mm/s. True 3D volumetric imaging of the ...

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    10. Intravascular optical coherence tomography imaging at 3200 frames per second

      Intravascular optical coherence tomography imaging at 3200 frames per second

      We demonstrate intravascular optical coherence tomography (OCT) imaging with frame rate up to 3.2 kHz (192,000 rpm scanning). This was achieved by using a custom-built catheter in which the circumferential scanning was actuated by a 1.0 mm diameter synchronous motor. The OCT system, with an imaging depth of 3.7 mm (in air), is based on a Fourier domain mode locked laser operating at an A-line rate of 1.6 MHz. The diameter of the catheter is 1.1 mm at the tip. Ex vivo images of human coronary artery (78.4 mm length) were acquired at ...

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    11. Numerical analysis of astigmatism correction in gradient refractive index lens based optical coherence tomography catheters

      Numerical analysis of astigmatism correction in gradient refractive index lens based optical coherence tomography catheters

      Endoscopic optical coherence tomography (OCT) catheters comprise a transparent tube to separate the imaging instrument from tissues. This tube acts as a cylindrical lens, introducing astigmatism into the beam. In this report, we quantified this negative effect using optical simulations of OCT catheter devices, and discuss possible compensation strategies. For esophageal imaging, the astigmatism is aggravated by the long working distance. For intracoronary imaging, the beam quality is degraded due to the liquid imaging environment. A nearly circular beam profile can be achieved by a curved focusing optics. We also consider the method of matching refractive indices, and it is ...

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    12. Handheld optical coherence tomography device for photodynamic therapy

      Handheld optical coherence tomography device for photodynamic therapy

      Photodynamic therapy (PDT) is a very effective treatment for port wine stains (PWS). To guide and assess PDT treatment, a handheld optical coherence tomography (OCT) probe was designed for real-time imaging of the PWS patient. The system uses a light source with a center wavelength of 1310 nm, -3 dB bandwidth of 90 nm and an optical power of 9 mW. The system also has a spatial resolution of 8 um (lateral) × 7 um (axial), an imaging rate of 4 frames per second, and a 102 dB sensitivity. We then demonstrate that the OCT imaging system can clearly distinguish between ...

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    13. Imaging port wine stains by fiber optical coherence tomography

      Imaging port wine stains by fiber optical coherence tomography

      We develop a fiber optical coherence tomography (OCT) system in the clinical utility of imaging port wine stains (PWS). We use our OCT system on 41 patients with PWS to document the difference between PWS skin and contralateral normal skin. The system, which operates at 4 frames/s with axial and transverse resolutions of 10 and 9 µm, respectively, in the skin tissue, can clearly distinguish the dilated dermal blood vessels from normal tissue. We present OCT images of patients with PWS and normal human skin. We obtain the structural parameters, including epidermal thickness and diameter and depth of dilated ...

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    14. Optical coherence tomography for ultrahigh-resolution 3D imaging of cell development and real-time guiding for photodynamic therapy

      Optical coherence tomography is a new emerging technique for cross-sectional imaging with high spatial resolution of micrometer scale. It enables in vivo and non-invasive imaging with no need to contact the sample and is widely used in biological and clinic application. In this paper optical coherence tomography is demonstrated for both biological and clinic applications. For biological application, a white-light interference microscope is developed for ultrahigh-resolution full-field optical coherence tomography (full-field OCT) to implement 3D imaging of biological tissue. Spatial resolution of 0.9µm×1.1µm (transverse×axial) is achieved A system sensitivity of 85 dB is obtained ...

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    1-14 of 14
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  2. Topics in the News

    1. (14 articles) Tianshi Wang
    2. (11 articles) Anton F. W. van der Steen
    3. (10 articles) Gijs van Soest
    4. (9 articles) Erasmus University
    5. (8 articles) Robert A. Huber
    6. (8 articles) Tom Pfeiffer
    7. (8 articles) Wolfgang Wieser
    8. (6 articles) Geert Springeling
    9. (5 articles) Ludwig Maximilian University of Munich
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    11. (1 articles) Nicolaus Copernicus University
    12. (1 articles) Harvard University
    13. (1 articles) Massachusetts General Hospital
    14. (1 articles) Technical University of Munich
    15. (1 articles) Fernando Alfonso
    16. (1 articles) Martin L. Villiger
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    Imaging port wine stains by fiber optical coherence tomography Handheld optical coherence tomography device for photodynamic therapy Numerical analysis of astigmatism correction in gradient refractive index lens based optical coherence tomography catheters Intravascular optical coherence tomography imaging at 3200 frames per second Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second Feature Of The Week 6/30/13: Ultrafast Intravascular Optical Coherence Tomography Imaging A Micromotor Catheter for Intravascular Optical Coherence Tomography Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography Feature Of The Week 09/10/2017: Thermo-elastic  Optical Coherence Tomography Prediction of scar size in rats six months after burns based on early post injury polarization-sensitive optical frequency domain imaging Optical coherence tomography in diagnosis and monitoring multiple sclerosis Very Late Scaffold Thrombosis: Insights from Optical Coherence Tomography and Histopathology