1. Articles from Tianyi Wang

    1-13 of 13
    1. Apparatus and methods for optical coherence tomography and two-photon luminescence imaging

      Apparatus and methods for optical coherence tomography and two-photon luminescence imaging

      Exemplary embodiments of the present disclosure include a combined catheter-based optical coherence tomography-two-photon luminescence (OCT-TPL) imaging system. Exemplary embodiments further include methods to detect, and further characterize the distribution of cellular components (e.g., macrophage, collagen/elastin fiber, lipid droplet) in thin-cap fibroatheromas with high spatial resolution in vivo.

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    2. Diagnosis of Thin-Capped Fibroatheromas in Intravascular Optical Coherence Tomography Images Effects of Light Scattering

      Diagnosis of Thin-Capped Fibroatheromas in Intravascular Optical Coherence Tomography Images Effects of Light Scattering

      Background— Intravascular optical coherence tomography (IVOCT) images are recorded by detecting light backscattered within coronary arteries. We hypothesize that non–thin-capped fibroatheroma (TCFA) causes may scatter light to create the false appearance of IVOCT TCFA. Methods and Results— Ten human cadaver hearts were imaged with IVOCT (n=14 coronary arteries). IVOCT and histological TCFA images were coregistered and compared. Of 21 IVOCT TCFAs (fibrous cap <65 μm, lipid arc >1 quadrant), only 8 were true histological TCFA. Foam cell infiltration was responsible for 70% of false IVOCT TCFA and caused both thick-capped fibroatheromas to appear as TCFA, and the appearance ...

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    3. Fourier optics analysis of phase-mask-based path-length-multiplexed optical coherence tomography

      Fourier optics analysis of phase-mask-based path-length-multiplexed optical coherence tomography

      Imaging below fingertip surface might be a useful alternative to the traditional fingerprint sensing since the internal finger features are more reliable than the external ones. One of the most promising subsurface imaging technique is optical coherence tomography (OCT), which, however, has to acquire 3-D data even when a single en face image is required. This makes OCT inherently slow for en face imaging and produce unnecessary large data sets. Here we demonstrate that full-field optical coherence tomography (FF-OCT) can be used to produce en face images of sweat pores and internal fingerprints, which can be used for the identification ...

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    4. Detection of plaque structure and composition using OCT combined with two-photon luminescence (TPL) imaging

      Detection of plaque structure and composition using OCT combined with two-photon luminescence (TPL) imaging

      Background and Objectives Atherosclerosis and plaque rupture leads to myocardial infarction and stroke. A novel hybrid optical coherence tomography (OCT) and two-photon luminescence (TPL) fiber-based imaging system was developed to characterize tissue constituents in the context of plaque morphology. Study Design/Materials and Methods Ex vivo coronary arteries (34 regions of interest) from three human hearts with atherosclerotic plaques were examined by OCT–TPL imaging. Histological sections (4 μm in thickness) were stained with Oil Red O for lipid, Von Kossa for calcium, and Verhoeff–Masson Tri-Elastic for collagen/elastin fibers and compared with imaging results. Results Biochemical components in ...

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    5. Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts

      Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts

      We sought to elucidate the mechanisms underlying two common intravascular optical coherence tomography (IV-OCT) artifacts that occur when imaging metallic stents: “merry-go-rounding” (MGR), which is an increase in strut arc length (SAL), and “blooming,” which is an increase in the strut reflection thickness (blooming thickness). Due to uncontrollable variables that occur in vivo , we performed an in vitro assessment of MGR and blooming in stented vessel phantoms. Using Xience V and Driver stents, we examined the effects of catheter offset, intimal strut coverage, and residual blood on SAL and blooming thickness in IV-OCT images. Catheter offset and strut coverage both ...

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    6. Apparatus And Methods For Optical Coherence Tomography And TWO-PHOTON Luminescence Imaging

      Apparatus And Methods For Optical Coherence Tomography And TWO-PHOTON Luminescence Imaging

      Exemplary embodiments of the present disclosure include a combined catheter- based optical coherence tomography - two-photon luminescence (OCT-TPL) imaging system. Exemplary embodiments further include methods to detect, and further characterize the distribution of cellular components (e.g., macrophage, collagen/elastin fiber, lipid droplet) in thin-cap fibroatheromas with high spatial resolution in vivo.

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    7. Development and application of optical imaging techniques in diagnosing cardiovascular disease (Thesis)

      Development and application of optical imaging techniques in diagnosing cardiovascular disease (Thesis)

      Atherosclerosis and specifically rupture of vulnerable plaques account for 23% of all deaths worldwide, far surpassing both infectious diseases and cancer. Plaque-based macrophages, often associated with lipid deposits, contribute to atherogenesis from initiation through progression, plaque rupture and ultimately, thrombosis. Therefore, the macrophage is an important early cellular marker related to vulnerability of atherosclerotic plaques. The objective of my research is to assess the ability of multiple optical imaging modalities to detect, and further characterize the distribution of macrophages (having taken up plasmonic gold nanoparticles as a contrast agent) and lipid deposits in atherosclerotic plaques. Tissue phantoms and macrophage cell ...

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    8. Dual-wavelength multifrequency photothermal wave imaging combined with optical coherence tomography for macrophage and lipid detection in atherosclerotic plaques using gold nanoparticles

      Dual-wavelength multifrequency photothermal wave imaging combined with optical coherence tomography for macrophage and lipid detection in atherosclerotic plaques using gold nanoparticles

      The objective of this study was to assess the ability of combined photothermal wave (PTW) imaging and optical coherence tomography (OCT) to detect, and further characterize the distribution of macrophages (having taken up plasmonic gold nanorose as a contrast agent) and lipid deposits in atherosclerotic plaques. Aortas with atherosclerotic plaques were harvested from nine male New Zealand white rabbits divided into nanorose- and saline-injected groups and were imaged by dual-wavelength (800 and 1210 nm) multifrequency (0.1, 1 and 4 Hz) PTW imaging in combination with OCT. Amplitude PTW images suggest that lateral and depth distribution of nanorose-loaded macrophages (confirmed ...

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    9. High-speed polarization sensitive optical coherence tomography for retinal diagnostics

      High-speed polarization sensitive optical coherence tomography for retinal diagnostics

      We report design and construction of an FPGA-based high-speed swept-source polarization-sensitive optical coherence tomography (SS-PS-OCT) system for clinical retinal imaging. Clinical application of the SS-PS-OCT system is accurate measurement and display of thickness, phase retardation and birefringence maps of the retinal nerve fiber layer (RNFL) in human subjects for early detection of glaucoma. The FPGA-based SS-PS-OCT system provides three incident polarization states on the eye and uses a bulk-optic polarization sensitive balanced detection module to record two orthogonal interference fringe signals. Interference fringe signals and relative phase retardation between two orthogonal polarization states are used to obtain Stokes vectors of ...

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    10. Changes in morphology and optical properties of sclera and choroidal layers due to hyperosmotic agent

      Changes in morphology and optical properties of sclera and choroidal layers due to hyperosmotic agent

      Light scattering in the normally white sclera prevents diagnostic imaging or delivery of a focused laser beam to a target in the underlying choroid layer. In this study, we examine optical clearing of the sclera and changes in blood flow resulting from the application of glycerol to the sclera of rabbits. Recovery dynamics are monitored after the application of saline. The speed of clearing for injection delivery is compared to the direct application of glycerol through an incision in the conjunctiva. Although, the same volume of glycerol was applied, the sclera cleared much faster (5 to 10 s) with the ...

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    11. Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms

      Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms

      Melanoma accounts for 75% of all skin cancer deaths. Pulsed photothermal radiometry (PPTR), optical coherence tomography (OCT) and ultrasound (US) are non-invasive imaging techniques that may be used to measure melanoma thickness, thus, determining surgical margins. We constructed a series of PDMS tissue phantoms simulating melanomas of different thicknesses. PPTR, OCT and US measurements were recorded from PDMS tissue phantoms and results were compared in terms of axial imaging range, axial resolution and imaging time. A Monte Carlo simulation and three-dimensional heat transfer model was constructed to simulate PPTR measurement. Experimental results show that PPTR and US can provide a ...

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    12. Depth resolved photothermal OCT detection of macrophages in tissue using nanorose

      Depth resolved photothermal OCT detection of macrophages in tissue using nanorose

      Application of photothermal Optical Coherence Tomography (OCT) to detect macrophages in ex vivo rabbit arteries which have engulfed nanoclusters of gold coated iron oxide (nanorose) is reported. Nanorose engulfed by macrophages associated with atherosclerotic lesions in rabbit arteries absorb incident laser (800nm) energy and cause optical pathlength (OP) variation which is measured using photothermal OCT. OP variation in polydimethyl siloxane tissue phantoms containing varying concentrations of nanorose match values predicted from nanoparticle and material properties. Measurement of OP variation in rabbit arteries in response to laser excitation provides an estimate of nanorose concentration in atherosclerotic lesions of 2.5x109 particles ...

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    13. Near infrared femtosecond laser ablation of urinary calculi in water

      Pulsed light emitted from a near infrared (=800nm) femtosecond laser is capable of plasma induced photodisruption of various materials. We used femtosecond laser pulses to ablate human urinary calculi. Femtosecond pulsed laser interaction with urinary calculi was investigated with various stone compositions, different incident fluences and number of applied pulses. Spectral-domain optical coherence tomography was used to image cross sections of ablation craters on the surface of urinary calculi. Our results indicate that femtosecond laser pulses can ablate various calculi compositions. Crater diameter and depth varies from tens of microns to several hundred microns when up to 1000 pulses were ...

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    1-13 of 13
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    Depth resolved photothermal OCT detection of macrophages in tissue using nanorose Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms Changes in morphology and optical properties of sclera and choroidal layers due to hyperosmotic agent High-speed polarization sensitive optical coherence tomography for retinal diagnostics Dual-wavelength multifrequency photothermal wave imaging combined with optical coherence tomography for macrophage and lipid detection in atherosclerotic plaques using gold nanoparticles Development and application of optical imaging techniques in diagnosing cardiovascular disease (Thesis) Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts Detection of plaque structure and composition using OCT combined with two-photon luminescence (TPL) imaging Fourier optics analysis of phase-mask-based path-length-multiplexed optical coherence tomography Normative data and associations of Optical Coherence Tomography Angiography measurements of the macula: The Singapore Malay Eye Study Automatic Segmentation and Measurement of Choroid Layer in High Myopia for OCT Imaging Using Deep Learning In-process monitoring in laser grooving with line-shaped femtosecond pulses using optical coherence tomography