1. Articles in category: Student Theses

    1-24 of 293 1 2 3 4 ... 11 12 13 »
    1. DEVELOPMENT OF PHASE DECORRELATION OPTICAL COHERENCE TOMOGRAPHY FOR ASSESSMENT OF THE OCULAR LENS AND CORNEA

      DEVELOPMENT OF PHASE DECORRELATION OPTICAL COHERENCE TOMOGRAPHY FOR ASSESSMENT OF THE OCULAR LENS AND CORNEA

      The human ocular system is tightly maintained in order to sharply focus images onto the retina. Our understanding of the ocular system has benefited from the study of biomechanical phenomena. For instance, the field has begun to understand a range of diseases as biomechanical in origin – such as keratoconus, glaucoma, and myopia. This mechanical understanding of disease has led to the development of new treatments, primarily crosslinking, which directly address the mechanical deficiency and have generally proved to be highly effective. Keratoconus, which until recently could only be treated through contact lenses and corneal transplants, can now be treated relatively ...

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    2. Multidimensional Data Processing for Optical Coherence Tomography Imaging (Thesis)

      Multidimensional Data Processing for Optical Coherence Tomography Imaging (Thesis)

      Optical Coherence Tomography (OCT) is a medical imaging technique which distinguishes itself by acquiring microscopic resolution images in-vivo at millimeter scale fields of view. The resulting in images are not only high-resolution, but often multi-dimensional to capture 3-D biological structures or temporal processes. The nature of multi-dimensional data presents a unique set of challenges to the OCT user that include acquiring, storing, and handling very large datasets, visualizing and understanding the data, and processing and analyzing the data. In this dissertation, three of these challenges are explored in depth: sub-resolution temporal analysis, 3-D modeling of fiber structures, and compressed sensing ...

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    3. Computational Methods for Image Acquisition and Analysis with Applications in Optical Coherence Tomography

      Computational Methods for Image Acquisition and Analysis with Applications in Optical Coherence Tomography

      The computational approach to image acquisition and analysis plays an important role in medical imaging and optical coherence tomography (OCT). This thesis is dedicated to the development and evaluation of algorithmic solutions for better image acquisition and analysis with a focus on OCT retinal imaging. For image acquisition, we first developed, implemented, and systematically evaluated a compressive sensing approach for image/signal acquisition for single-pixel camera architectures and an OCT system. Our evaluation outcome provides a detailed insight into implementing compressive data acquisition of those imaging systems. We further proposed a convolutional neural network model, LSHR-Net, as the first deep-learning ...

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    4. Towards estimation of optical and structural ophthalmic properties based on optical coherence tomography

      Towards estimation of optical and structural ophthalmic properties based on optical coherence tomography

      Early diagnosis of retinal diseases such as glaucoma will benefit from unbiased an precise estimation of both optical and structural properties of the RNFL as they provide a better understanding of the tissue characteristics. The main objective of this thesis was first to improve the estimation of the attenuation coefficients of layered samples and, second, to estimate the structural properties of RNFL. Unbiased estimation of optical tissue properties such as the attenuation coefficient require a model of the recorded OCT signal. To study the characteristics of the OCT signal, in Chapter 2, two simulation methods were presented for homogeneous samples ...

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    5. Optical coherence tomography (OCT) and irreversible electroporation (IRE) in the diagnosis and treatment of renal masses

      Optical coherence tomography (OCT) and irreversible electroporation (IRE) in the diagnosis and treatment of renal masses

      The first aim of this thesis is to investigate the diagnostic value of needle-based, percutaneous optical coherence tomography (OCT) in the differentiation of renal masses. Secondly, the feasibility and safety of percutaneous, irreversible electroporation (IRE) are assessed for the treatment of SRMs.

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    6. Multidimensional Data Processing for Optical Coherence Tomography Imaging (Thesis)

      Multidimensional Data Processing for Optical Coherence Tomography Imaging (Thesis)

      Optical Coherence Tomography (OCT) is a medical imaging technique which distinguishes itself by acquiring microscopic resolution images in-vivo at millimeter scale fields of view. The resulting in images are not only high-resolution, but often multi-dimensional to capture 3-D biological structures or temporal processes. The nature of multi-dimensional data presents a unique set of challenges to the OCT user that include acquiring, storing, and handling very large datasets, visualizing and understanding the data, and processing and analyzing the data. In this dissertation, three of these challenges are explored in depth: sub-resolution temporal analysis, 3-D modeling of fiber structures, and compressed sensing ...

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    7. The use of optical coherence tomography to enhance surgical margin assessment for canine mast cell tumors (Thesis)

      The use of optical coherence tomography to enhance surgical margin assessment for canine mast cell tumors (Thesis)

      Experiment 1: Objective: To document the appearance of artifacts created by commonly encountered surgical conditions and instrumentation on optical coherence tomography (OCT) and compare these findings with histopathology. Study design: Ex vivo study Animals: 5 canine cadavers Methods: Skin, subcutaneous fat, skeletal muscle, and fascia samples were obtained from fresh canine cadavers. Blood pooling, hemostatic crushing, scalpel blade cut, monopolar electrosurgery, bipolar vessel sealing device and ultrasonic energy surgical artifacts were induced on each tissue type. Each specimen was interrogated with OCT and subsequently histologically processed. Results: The majority of surgical instrumentation used for tumor excision created a high-scattering region ...

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    8. Automated Algorithm for Optical Coherence Tomography (OCT) Images of 3D Spheroids (Thesis)

      Automated Algorithm for Optical Coherence Tomography (OCT) Images of 3D Spheroids (Thesis)

      The application of three-dimensional (3D) tumor spheroids has been expanding due to their ability to closely mimic several features of solid tumors such as their cellular heterogeneity/organization and growth kinetics. Optical Coherence Tomography (OCT) system has been utilized to characterize 3D morphological and physiological information of multicellular tumor spheroids. In order to characterize and analyze the results of 3D OCT spheroid datasets, there is a need to develop an automated algorithm with high accuracy that can calculate the volume of a tumor spheroid and its necrotic tissues. The developed automated algorithm can automatically detect the margin of the 3D ...

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    9. Characterization Of The Macular Choriocapillaris In Dry Age-Related Macular Degeneration Using Swept-Source Optical Coherence Tomography Angiography (Thesis)

      Characterization Of The Macular Choriocapillaris In Dry Age-Related Macular Degeneration Using Swept-Source Optical Coherence Tomography Angiography (Thesis)

      The purpose of this study was to characterize further, using swept-source (SS-) optical coherence tomography angiography (OCTA), the relationship between dry age-related macular degeneration (AMD) and the macular choriocapillaris (CC), which may have pathophysiologic and therapeutic implications. It included (1) a topographic analysis to determine if there is a significant relationship between dry AMD stage and macular CC perfusion, and (2) an investigation of the predictive value of macular CC perfusion with respect to geographic atrophy (GA) growth rate. Study design was retrospective and cross-sectional. A database of 6x6 mm fovea-centered swept-source OCTA images of the CC from eyes with ...

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      Mentions: Yale University
    10. High-speed Time-stretch Optical Coherence Tomography (Thesis)

      High-speed Time-stretch Optical Coherence Tomography (Thesis)

      Supercontinuum sources have great potential in optical coherence tomography due to their ultrabroad spectra, which provide ultrahigh resolution images. High intensity noise of conventional supercontinuum sources, however, has been the limiting factor of widespread adoption, but the emergence of low noise supercontinuum sources promise to change this. In this thesis, both types of supercontinuum sources are tested in a spectrometer-based optical coherence tomography setup, where it is found that the low noise supercontinuum is able to produce the shot noise limited images, a feat that is not replicated by the conventional supercontinuum. Furthermore, the two types of supercontinuum sources are ...

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    11. Image-guidance in ophthalmic surgery using optical coherence tomography (Thesis)

      Image-guidance in ophthalmic surgery using optical coherence tomography (Thesis)

      Ophthalmic surgery involves manipulation of layered tissue structures on milli- to micrometer scales. Traditional surgical microscopes provide a two-dimensional view of the surgical field with limited depth perception which precludes accurate depth-resolved visualization of surgically-induced tissue morphology. Optical coherence tomography (OCT) enables non-contact exogenous contrast-free imaging of subsurface tissue microstructures, and is currently the gold standard for ophthalmic clinical diagnostics. Over the last decade, translation of OCT technologies to applications in surgical planning and guidance in ophthalmology has been an active area of research and commercialization. Clinical studies confirmed benefits of intraoperative OCT including verification that surgical goals have been ...

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    12. Studying Cerebral Blood Flow in Mouse Cortex with Optical Microangiography (Thesis)

      Studying Cerebral Blood Flow in Mouse Cortex with Optical Microangiography (Thesis)

      Optical coherence tomography (OCT) is a non-contact three-dimensional (3D) imaging modality which enables fast in vivo volumetric visualization of internal structures of biological tissues with high resolution. In this thesis, first, the application of OCT advanced extension - optical microangiography (OMAG) - was used to reveal the temporal profile of hemodynamic response to neural activation and the variation of depth-resolved blood flow changes in mouse cerebral cortex. The results showed that the largest hemodynamic response occurred in cortical layer IV. Second, OMAG and Doppler OMAG (DOMAG) techniques were applied to quantitatively evaluate the anesthesia effect on cerebral vessel morphology and blood flow ...

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    13. Traction force optical coherence microscopy: a new method to study the dynamic mechanical behavior of cells and multicellular collectives within scattering media (Thesis)

      Traction force optical coherence microscopy: a new method to study the dynamic mechanical behavior of cells and multicellular collectives within scattering media (Thesis)

      Mechanobiology is a prominent research field which seeks to elucidate the role of physical forces and mechanical interactions throughout various biological processes, including morphogenesis, wound healing, and cancer metastasis, among others. Traction force microscopy (TFM) is an important family of experimental techniques used by mechanobiologists to study and quantify the forces that cells exert upon their surroundings. Recent years have seen a growing demand for TFM methods capable of studying the dynamic, 3D, and collective behaviors of cells embedded within optically scattering media. However, traditional imaging modalities for TFM (e.g., confocal microscopy) do not currently allow researchers to satisfy ...

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    14. Deep learning for quantitative motion tracking based on optical coherence tomography (Thesis)

      Deep learning for quantitative motion tracking based on optical coherence tomography (Thesis)

      Optical coherence tomography (OCT) is a cross-sectional imaging modality based on low coherence light interferometry. OCT has been widely used in diagnostic ophthalmology and has found applications in other biomedical fields such as cancer detection and surgical guidance. In the Laboratory of Biophotonics Imaging and Sensing at New Jersey Institute of Technology, we developed a unique needle OCT imager based on a single fiber probe for breast cancer imaging. The needle OCT imager with sub-millimeter diameter can be inserted into tissue for minimally invasive in situ breast imaging. OCT imaging provides spatial resolution similar to histology and has the potential ...

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    15. Optical coherence tomography vs fundus photography in detecting macular edema in subjects with type 2 diabetes (Thesis)

      Optical coherence tomography vs fundus photography in detecting macular edema in subjects with type 2 diabetes (Thesis)

      Introduction The screening of diabetic retinopathy has been relied on fundus photography but since it is 2-dimensional, it is difficult to identify diabetic macular edema (DME), which is the most feared ocular complication related to diabetes. Optical coherence tomography (OCT) has been shown to be a useful tool in detecting and monitoring DME. The main objective of this study was to screen people with type 2 diabetes and find out how many patients have current diabetic macular edema and to compare different screening equipment by means of fundus photography and OCT when evaluating macular edema. Method The sample of this ...

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    16. Measuring 3D Optic Nerve Head Deformations using Digital Volume Correlation of in vivo Optical Coherence Tomography Data (Thesis)

      Measuring 3D Optic Nerve Head Deformations using Digital Volume Correlation of in vivo Optical Coherence Tomography Data (Thesis)

      The optic nerve head (ONH), located in the back of the eye, is a critical site in understanding the pathophysiology of glaucoma. However, longitudinal changes of the ONH as disease develops have not been well characterized. Our goal was to develop an improved tool to quantify these changes in an in vivo monkey model of glaucoma. Longitudinal spectral-domain optical coherence tomography (OCT) imaging of the ONH was performed every other week under manometric intraocular pressure (IOP) control (10 mmHg) in a monkey during baseline and after induction of unilateral experimental glaucoma. We developed a computational pipeline that applied digital volume ...

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    17. Optical coherence tomography for characterization of nanocomposite materials (Thesis)

      Optical coherence tomography for characterization of nanocomposite materials (Thesis)

      Nanocomposite materials play an increasingly important role in various application areas, be it in an industrial, medical or everyday environment. The unique properties of nanocomposites go beyond those of conventional composite materials. Because nanoparticles have a high surface-to-volume ratio such as carbon nanotubes, they can reinforce an embedding polymer host matrix mechanically, or they enhance the electrical material conductivity. A major challenge in the development of nanoparticles and nanocomposites is the control of particle size and shape, and of the uniform dispersion of nanoparticles in the host material. Conventional characterization techniques lack either resolution, or can only inspect details of ...

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    18. Red-light Heartbeat Control and Optical Coherence Microscopy (OCM) Imaging in Drosophila (Thesis)

      Red-light Heartbeat Control and Optical Coherence Microscopy (OCM) Imaging in Drosophila (Thesis)

      would like to thank my advisor Prof. Chao Zhou, who gave me the opportunity to pursue a higher-level education in the United States, and led me to the field of biomedical engineering. I still have the impression that I was attracted by the fast heartbeat of a Drosophila Prof. Zhou showed with a video in his presentation in Peking University in 2014. I was curious that how the fast heartbeat could be tracked using OCT. Fortunately, I got the opportunity to join the group during that summer. In the next several years during my PhD period, Prof. Zhou guided me ...

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    19. Functional High-Speed Optical Coherence Tomography (Thesis)

      Functional High-Speed Optical Coherence Tomography (Thesis)

      Optical coherence tomography (OCT) is a high speed, high resolution, noninvasive imaging technique that has seen applications across many clinical and biological research fields, with a particular focus in ophthalmic, cardiologic and dermatologic imaging. Ultrahigh speed OCT imaging has become of interest for high resolution, widefield in vivo imaging. Space division multiplexing optical coherence tomography (SDM-OCT) is a novel optical coherence tomography system which utilizes a parallel imaging approach to achieve ultrahigh imaging speeds. In this dissertation we develop an ophthalmic SDM-OCT system to obtain widefield structural and angiographic images of the human retina in vivo. With an 800 kHz ...

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    20. Robotics and Virtual Reality for Optical Coherence Tomography-Guided Ophthalmic Surgery and Diagnostics (Thesis)

      Robotics and Virtual Reality for Optical Coherence Tomography-Guided Ophthalmic Surgery and Diagnostics (Thesis)

      Ophthalmology is the only surgical specialty that routinely employs both microsurgical techniques and live intraoperative imaging, especially optical coherence tomography (OCT). Consequently, ophthalmic surgeons routinely face challenges in visualization and manipulation of small ocular tissues or in interpreting intraoperative imaging to guide their actions. This dissertation therefore seeks to advance the state-of-the-art in ophthalmic surgery with regards to manipulation, visualization, and interpretation. First, we address the interpretation challenge in ophthalmic surgery where live volumetric imaging from OCT systems recently incorporated into surgical microscopes has freed surgeons from the otherwise universal top-down viewpoint. These new viewpoints, however, disorient surgeons when directions ...

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      Mentions: Duke University
    21. Advances in Optical Coherence Tomography for Retinal Oximetry and Angiography (Thesis)

      Advances in Optical Coherence Tomography for Retinal Oximetry and Angiography (Thesis)

      Optical coherence tomography (OCT) is a high-resolution, non-contact, three-dimensional imaging technique, which has revolutionized the diagnosis and treatment of retinal diseases. Visible-light OCT (vis-OCT) extends OCT by enabling retinal oximetry – the measurement of oxygen saturation of hemoglobin from within individual retinal blood vessels. Three advances in the vis-OCT technique are presented: an improved vis-OCT oximetry method based on circumpapillary scan and graph-search segmentation; the calibration, simulation, and correction of spectroscopic sensitivity rolloff for vis-OCT oximetry; and the measurement of the inner retinal oxygen metabolism in the 50/10 oxygen-induced retinopathy model, an animal model for human retinopathy of prematurity. Optical ...

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    22. The analysis of prostate tissue by optical coherence tomography (Thesis)

      The analysis of prostate tissue by optical coherence tomography (Thesis)

      The prostate is the gland located around the urethra beneath the bladder that produces most of the sperm fluid (figure 1). Prostate cancer (PCa) accounted for almost 1 in 5 new cancer diagnoses in males in the USA in 2017, and 1 in 8 men will develop invasive cancer in the prostate in their lifetime [1]. Prostate cancer is the second most common cancer in men (after skin cancer) and the second most common cause of cancer-related death (after lung cancer). Advances in screening, diagnosis, and treatment have led to an overall survival increase from 69% in 1991-1995 to 89 ...

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    23. Invasive Coronary Artery Imaging Using Optical Coherence Tomography: A Cost-effectiveness and Implementation Process Analysis (Thesis)

      Invasive Coronary Artery Imaging Using Optical Coherence Tomography: A Cost-effectiveness and Implementation Process Analysis (Thesis)

      The aim of this project was the implementation of optical coherence tomography (OCT), an invasive intracoronary imaging (ICI) tool used for the visualization of coronary arteries. The implementation was performed in a structured manner by: (1) A literature review into the current applications of OCT in relation to current standards; (2) A thesis feasibility study into clinical practices, professional views and other processes regarding ICI; (3) A Master’s thesis including a cost-effectiveness analysis (CEA) and the actual implementation of OCT at the department. The project started with a literature review about the current applications of OCT in relation to ...

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