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Download or read book High-speed Polarization-sensitive Optical Coherence Tomography: Toward Intraoperative Cancer Imaging written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Milos Todorovic
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (69 download)
Download or read book Time-domain Polarization-sensitive Optical Coherence Tomography in Soft Biological Tissue written by Milos Todorovic and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new, high-speed, fiber-based Mueller-matrix optical coherence tomography system with continuous source-polarization modulation is presented. For in vivo experimentation, the sample arm optics are integrated into a hand-held probe. The system0́9s parameters were verified through imaging standard optical elements. A unique feature of polarization-sensitive Mueller optical coherence tomography is that by measuring Jones or Mueller matrices, it can reveal the complete polarization properties of biological samples, even in the presence of diattenuation. Presented here for the first time are mapped local polarization properties of biological samples obtained by using polar decomposition in combination with least-squares fitting to differentiate measured integrated Jones matrices with respect to depth. In addition, a new concept of dual attenuation coefficients to characterize diattenuation per unit infinitesimal length in tissues is introduced. The algorithm was experimentally verified using measurements of a section of porcine tendon and the septum of a rat heart. The application of the system for burn imaging and healing monitoring was demonstrated on porcine skin because of its similarity to the human skin. The results showed a clear localization of the thermally damaged region. The local birefringence of the intravital porcine skin was mapped by using a differentiation algorithm. The burn areas in the OCT images agree well with the histology, thus demonstrating the system0́9s potential for burn-depth determination and post-injury healing monitoring. Another major application of the fiber-based Mueller-matrix optical coherence tomography system with continuous source-polarization modulation covered here is in vivo imaging of early stages of skin cancer. The OCT images of SENCAR mice skin affected by the tumorigenesis show the structural changes in skin resulting from precancerous papilloma formations that are consistent with histology, which proves the system0́9s potential for early skin cancer detection.
Author : Miao Zhang
Publisher :
ISBN 13 :
Total Pages : 144 pages
Book Rating : 4.:/5 (967 download)
Download or read book Towards High Speed High Sensitivity Optical Coherence Tomography for in Vivo Functional Imaging written by Miao Zhang and published by . This book was released on 2015 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation has developed several innovative techniques based on physics and engineering towards a high speed and high sensitivity optical coherence tomography (OCT) for in vivo functional imaging of biological subjects. We applied innovation to a dual-band Fourier domain OCT (FD-OCT) that provides depth-resolved spectroscopic imaging, enhancing tissue contrast and reduces image speckle. Previous dual-band FD-OCT systems could not correctly give the tissue spectroscopic contrast due to depth-related discrepancy in the imaging modality and attenuation in biological tissue samples. We successfully designed a new dual-band full-range FD-OCT imaging and developed an algorithm to compensate the depth-related fall-off and light attenuation. In our imaging system, the complex conjugate artifact is suppressed using a new spatial convolution approach. A graphics processing unit (GPU) accelerates the system for ultrahigh speed processing. Improved spectroscopic contrast and sensitivity were achieved in imaging tissue phantoms, human cancer xenografts and muscle tissues dissected from severely compromised immune deficient mice as well as living mice, benefiting from the depth-related compensations. We further developed an OCT imaging using a finite energy Airy beam that is generated with a phase mask. The depth of field (DOF) is greatly improved in comparison with traditional OCT systems using focused Gaussian beam. We demonstrated that a tradeoff between the sensitivity and the DOF can be controlled by the decay factor of the finite energy Airy beam via changing the pattern scale of on the phase mask.
Author : Mark E. Brezinski
Publisher : Elsevier
ISBN 13 : 0080464947
Total Pages : 645 pages
Book Rating : 4.0/5 (84 download)
Download or read book Optical Coherence Tomography written by Mark E. Brezinski and published by Elsevier. This book was released on 2006-08-25 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Coherence Tomography gives a broad treatment of the subject which will include 1)the optics, science, and physics needed to understand the technology 2) a description of applications with a critical look at how the technology will successfully address actual clinical need, and 3) a discussion of delivery of OCT to the patient, FDA approval and comparisons with available competing technologies. The required mathematical rigor will be present where needed but be presented in such a way that it will not prevent non-scientists and non-engineers from gaining a basic understanding of OCT and the applications as well as the issues of bringing the technology to the market. - Optical Coherence Tomography is a new medical high-resolution imaging technology which offers distinct advantages over current medical imaging technologies and is attracting a large number of researchers. - Provides non-scientists and non-engineers basic understanding of Optical Coherence Tomography applications and issues.
Author : Yueli Chen
Publisher :
ISBN 13 :
Total Pages : 240 pages
Book Rating : 4.:/5 (711 download)
Download or read book Optical Coherence Tomography Instrumentation and Application written by Yueli Chen and published by . This book was released on 2006 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Peijun Tang
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)
Download or read book Development and Application of Polarization Sensitive Optical Coherence Tomography written by Peijun Tang and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT), a three-dimensional optical imaging technique based on low coherence interferometry, can be extended to measure the functional property of the biological sample. As a functional extension of OCT, polarization sensitive optical coherence tomography (PSOCT) enables 3D imaging of the anisotropic biological samples, such as scar, tendon, muscle, collagen, and nerve fiber bundles. This thesis focuses on the development and application of PSOCT. This goal includes four specific aims. The first aim is to develop a single input PSOCT imaging system with an improved image contrast. To achieve this aim, the polarization state is utilized as the imaging parameter and visualized using the Stokes parameters-based color-encoded algorithm. The second aim is to develop an algorithm that can derive depth-resolved polarization parameters with the single input PSOCT system. Towards this aim, a PSOCT-based polarization state transmission model is proposed. Based on this model, a novel method that utilizes discrete differential geometry (DDG) combined with a series of 3D rotations is developed to derive the local axis orientation and phase retardation. The third aim is to use the developed DDG-based PST method to extract the collagen organization embedded within the soft biological tissues. To achieve this aim, the proposed method is utilized to image the local axis orientation of the collagen fibers of the rodent heart and human facial skin. The fourth aim is to use the multiparameter provided by the PSOCT to detect and characterize the white spot lesions in the enamel of the tooth. Towards this aim, multiple parameters in the PSOCT: scattering, attenuation, degree of polarization (DOP), local axis orientation, and local phase retardation of the sample are provided simultaneously for the comprehensive investigation of the location, depth, and severity of the white spot lesions.
Download or read book Development and Application of Optical Coherence Tomography (Oct). written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 : 9789493330344
Total Pages : 0 pages
Book Rating : 4.3/5 (33 download)
Download or read book Imaging of Fiber Structures in the Posterior Eye written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imaging the human body is the most important diagnostic tool in healthcare. Therefore, there is an endless need for improvement of imaging techniques. In this thesis, an extension of a medical imaging technique is further developed to provide extra image contrast based on polarization-changing properties of the tissue. This technique, called polarization-sensitive optical coherence tomography (PS-OCT), is an extension of optical coherence tomography (OCT), which is often used in ophthalmology to create high resolution images of the retina of the human eye. Retinal imaging is the main application of PS-OCT chosen for this thesis. Extra image contrast in PS-OCT includes imaging of birefringence, depolarization, and optic axis of the tissue. An in-house built PS-OCT setup is presented and improved. This setup is then used throughout the thesis to create 3D in vivo retinal images of healthy volunteers and patients. Improvements of PS-OCT data analysis are presented and demonstrated in healthy volunteers. A new imaging metric, optic axis uniformity (OAxU), is introduced. OAxU is defined as the length of the spatially averaged optic axis and varies between 0 and 1. Differential Mueller matrix calculations have been implemented and improved to visualize birefringent structures and their optic axes locally. A deep-learning model is developed as a tool to segment the PS-OCT images. Improvement of PS-OCT analysis allows for orientation images of the collagen in the peripapillary sclera, revealing a radially oriented fiber layer preceding a circumferentially orientated fiber layer. Close to the optic nerve head (ONH), the circumferentially oriented layer displaces the radially oriented fiber layer. PS-OCT is used to image patients with high myopia, glaucoma, osteogenesis imperfecta (OI) or wet age-related macular degeneration (wAMD) to compare the visualization of these new findings in ocular fibrillar architecture to healthy volunteers. These diseases are relevant for PS-OCT imaging to detect changes in scleral collagen, damage to the RNFL, or subretinal fibrosis. Multiple parameters are investigated in this study, including birefringence of the sclera and its correlation with axial length, orientations of RNFL in glaucoma patients, dimensions of the circularly oriented sclera (COS) ring, and thickness of the radially oriented sclera (ROS) layer. The ROS is thinner in myopia patients and OI patients. Besides a thinner ROS layer, birefringence of the sclera was lower in OI patients. Fibrosis can be detected and its orientation can be determined in 3D in AMD patients. Fibrosis shows a higher organization than expected and was often observed in large patches of similar orientations which can vary in depth. The applicability of (PS-)OCT goes beyond ophthalmology. In this thesis, it is investigated whether PS-OCT would be valuable in the imaging of airway. Multiple diseased lungs and healthy lungs are imaged ex vivo to investigate differences in alveoli size/presence and ASM thickness. Optic axis orientation images proved very useful to discriminate different birefringent structures, which is not possible in standard OCT imaging. This allowed for automatic ASM segmentation which is relevant for diseases were this layer is thickened such as asthma, fibrotic sarcoidosis (FS), and fibrotic hypersensitivity pneumonitis (fHP).
Author : Amit Shrikant Paranjape
Publisher :
ISBN 13 :
Total Pages : 354 pages
Book Rating : 4.:/5 (732 download)
Download or read book Application of Polarization Sensitive Optical Coherence Tomography (PS-OCT) and Phase Sensitive Optical Coherence Tomography (PhS-OCT) for Retinal Diagnostics written by Amit Shrikant Paranjape and published by . This book was released on 2011 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Enhanced Polarization-Sensitive Swept Source Optical Coherence Tomography (EPS-SS-OCT) instrument for high sensitivity cross-sectional imaging of Retinal Nerve Fiber Layer (RNFL) has been designed, constructed, and verified. The instrument is capable of measuring the thickness and birefringence of the RNFL. Birefringence change of the RNFL could serve as an early indicator of glaucoma. The associated image processing methods for completely automated, time efficient algorithm to segment the RNFL in images of the human retina recorded by the EPS-SS-OCT. Detected RNFL boundaries are used to compute peripapillary thickness maps. Numerical algorithms to compute the birefringence of the detected RNFL layer are presented along with the associated phase retardation and birefringence peripapillary maps. Glaucoma affects the vitality of retinal ganglion cell axons in the retinal nerve fiber layer (RNFL) and may be clinically detected through a change in RNFL birefringence. Comprehensive peripapillary maps of healthy and glaucoma suspect human RNFL birefringence were constructed using EPS-SS-OCT. Presence of macrophages is a hallmark of several retinal diseases such as drusen and age related macular degeneration. Application of photothermal Optical Coherence Tomography (OCT) to detect macrophages in ex vivo arteries which have engulfed nanoclusters of gold coated iron oxide (nanorose) is reported. Nanorose engulfed by macrophages in 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 arteries in response to laser excitation provides an estimate of nanorose concentration in arteries 2.5x109 particles/ml. OP variation in nanoparticle containing artery sections and tissue phantoms taking up nanorose has a different magnitude and profile from that observed in control aorta and phantoms without macrophages and is consistent with macrophage presence as identified with RAM-11 histology staining. Our results suggest that tissue regions with macrophages taking up nanorose can be detected using photothermal OCT.
Author : Patrick Wai-Kit Yiu
Publisher :
ISBN 13 :
Total Pages : 117 pages
Book Rating : 4.:/5 (13 download)
Download or read book High Speed Swept Source Optical Coherence Tomography Handheld Instrument at 1310nm for Point-of-care Imaging written by Patrick Wai-Kit Yiu and published by . This book was released on 2018 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is a novel biomedical imaging technique that functions as a type of "optical biopsy" by using low coherence interferometry to non-invasively generate high resolution cross-sectional images of tissue in real time. OCT has become a standard diagnostic tool in ophthalmology and investigators have demonstrated OCT in a variety of biomedical applications including cardiology, gastroenterology, dermatology, and urology. Recent research advances in swept source lasers have enabled swept source OCT (SS-OCT) to achieve imaging speeds 5-50x faster than commercially available spectral domain OCT (SD-OCT) systems. This thesis describes the design of a handheld SS-OCT instrument for portable-real-time imaging in situ at the point of care. Traditional OCT devices require bulky table-mounted systems, but the handheld device has the potential to be used as an advanced point-of-care diagnostic instrument in primary care settings or intraoperatively. The combination of the wide scanning angle in the handheld and the high imaging speed of SS-OCT could allow for screening of pathology with a single volumetric data set spanning the areas of interest on the patient. The compact, easy-to-use form factor could enable the adoption of SS-OCT in settings like primary care clinics or the surgical theater where space is limited. Emergent applications can include intraoperative assessment of kidney transplant viability, as many donor kidneys suffer ischemic insult while awaiting transplant and there is a critical clinical need for a reliable, real-time assay to evaluate donor kidney viability and predict post-transplant outcome.
Author : Ahhyun Nam
Publisher :
ISBN 13 :
Total Pages : 167 pages
Book Rating : 4.:/5 (986 download)
Download or read book Development and Translation of Label-free Functional Microscopy Based on Optical Coherence Tomography written by Ahhyun Nam and published by . This book was released on 2017 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT), an imaging modality based on low coherence interferometry, can be extended to obtain various endogenous functional contrasts. This thesis focuses on the development and translation of angiographic and polarization sensitive (PS) OCT techniques for clinical and preclinical applications. This goal includes four specific aims. The first aim is to develop a clinical imaging system to image the anatomy and microvasculature of human skin. The second aim is to develop a high performance post-processing algorithm for angiographic OCT. Towards this aim, we developed a processing algorithm based on complex differential variance (CDV) and confirmed its performance by benchmarking it against other published algorithms. The third aim is to develop a new approach for achieving high spatial resolution with an extended depth of focus for angiographic imaging. To achieve this aim, we have designed and built a triband wavelength system in which each spectrum is tightly focused at displaced focal planes to yield high transverse resolution over an effectively extended depth range. The fourth aim is to provide an imaging platform for preclinical study of peripheral nerve injury and repair. The vascularization is assessed by angiographic OCT, and the degree of myelination is measured by PS-OCT. These results confirm that the OCT platform can reveal new insights into preclinical studies of nerve regeneration and may ultimately provide a means for clinical intraoperative assessment of peripheral nerve health.
Author : Bettina Heise
Publisher : Sudwestdeutscher Verlag Fur Hochschulschriften AG
ISBN 13 : 9783838120584
Total Pages : 180 pages
Book Rating : 4.1/5 (25 download)
Download or read book Image Processing for Phase-Sensitive Optical Coherence Tomography written by Bettina Heise and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2010-11 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phase-sensitive imaging techniques, suitable for investigating structures in the micron range, are discussed in this book with a focus on optical coherence tomography (OCT). The probed samples are mostly of technical nature, but the methods in general are not restricted to technical applications. Moreover, several imaging aspects, originating from biological applications, recently have been transferred to technical material sciences. OCT imaging is presented here mainly by its phase-sensitive modifications: polarization-sensitive OCT (PS-OCT) and differential phase contrast OCT (DPC-OCT). The comparison to quantitative imaging in phase contrast microscopy techniques has been drawn to illustrate the similarities, differences, and limitations of both techniques. The potential for appropriate image processing is demonstrated in this context to obtain improved quantitative and localized information about specimens and material behavior. The book connects the field of optics, mathematics, and image processing from an interdisciplinary point of view.
Author : Kye-Sung Lee
Publisher :
ISBN 13 :
Total Pages : 142 pages
Book Rating : 4.:/5 (528 download)
Download or read book Extended Focus Range High Resolution Endoscopic Optical Coherence Tomography written by Kye-Sung Lee and published by . This book was released on 2008 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, medical imaging is playing an important role in medicine as it provides the techniques and processes used to create images of the human body or parts thereof for clinical purposes (medical procedures seeking to reveal, diagnose or examine disease) or medical science (including the study of normal anatomy and function). Modalities are developing over time to achieve the highest possible resolution, speed of image acquisition, sensitivity, and specificity. In the past decade, advances in optics, fiber, as well as laser technology have enabled the development of noninvasive optical biomedical imaging technology that can also be applied to endoscopy to reach deeper locations in the human body. The purpose of this dissertation is to investigate a full system design and optimization of an optical coherence tomography (OCT) system to achieve high axial and lateral resolution together with an extended depth of focus for endoscopic in vivo imaging. In this research aimed at advancing endoscopic OCT imaging, two high axial resolution optical coherence tomography systems were developed: (1) a spectrometer-based frequency-domain (FD) OCT achieving an axial resolution of ~2.5 [micrometers] using a Ti:Sa femtosecond laser with a 120nm bandwidth centered at 800nm and (2) a swept-source based FD OCT employing a high speed Fourier domain mode locked (FDML) laser that achieves real time in vivo imaging with ~8 [micrometers] axial resolution at an acquisition speed of 90,000 A-scans/sec. A critical prior limitation of FD OCT systems is the presence of mirror images in the image reconstruction algorithm that could only be eliminated at the expense of depth and speed of imaging. A key contribution of this research is the development of a novel FD OCT imager that enables full range depth imaging without a loss in acquisition speed. Furthermore, towards the need for better axial resolution, we developed a mathematical model of the OCT signal that includes the effect on phase modulation of phase delay, group delay, and dispersion. From the mathematical model we saw that a Fourier domain optical delay line (FD ODL) incorporated into the reference arm of the OCT system represented a path to higher performance. Here we then present a method to compensate for overall system dispersion with a FDODL that maintains the axial resolution at the limit determined solely by the coherence length of a broadband source. In the development of OCT for endoscopic applications, the need for long depth of focus imaging is critical to accommodate the placement of the catheter anywhere within a vessel. A potential solution to this challenge is Bessel-beam imaging. In a first step, a Bessel-beam based confocal scanning optical microscopy (BCSOM) using an axicon and single mode fiber was investigated with a mathematical model and simulation. The BCSOM approach was then implemented in a FD OCT system that delivered high lateral resolution over a long depth of focus. We reported on the imaging in biological samples for the first time with a double-pass microoptics axicon that demonstrated clearly invariant SNR and 8 [micrometers] lateral resolution images across a 4 mm depth of focus. Finally, we describe the design and fabrication of a catheter incorporated in the FD OCT. The design, conceived for a 5 mm outer diameter catheter, allows 360 degree scanning with a lateral resolution of about 5 [micrometers] across a depth of focus of about 1.6 mm. The dissertation concludes with comments for related future work.
Author : Michael Christopher Oliveira
Publisher :
ISBN 13 : 9781321320367
Total Pages : 103 pages
Book Rating : 4.3/5 (23 download)
Download or read book Multi-scale Optical Coherence Tomography Imaging written by Michael Christopher Oliveira and published by . This book was released on 2014 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: An optical modality capable of quantitative, label-free, high-speed and high-resolution imaging across spatiotemporal scales coupled with sophisticated software for image reconstruction and quantitative analyses would be of great utility to scientists and engineers in the medical and life sciences fields. Currently, a combination of optical imaging techniques and software packages are needed to address the list of capabilities described previously. Optical coherence tomography is an optical imaging technique based on low coherence interferometry capable of measuring light backscattered from the sample at micrometer-level resolutions over millimeter-level penetration depths in biological tissue. Phase-sensitive extensions of OCT enable the functional assessment of biological tissue samples as well as the structural examination of samples down to the single-cell level. This dissertation describes the development and application of high-speed real-time multi-functional spectral-domain OCT (MF-SD-OCT) for structural and functional examination of biological samples across spatiotemporal scales. A discussion of the development of a GPU-accelerated high-speed MF-SD-OCT imaging system accompanied by demonstrations of the performance enhancements due to the GPU are presented initially. Next, the development of MF-SD-OCT-based quantitative methods for the structural and functional assessment and characterization and classification of biological tissue samples is discussed. The utility of these methods is demonstrated through structural, functional and optical characterization and classification of peripheral nerve and muscle tissue. The dissertation concludes with a discussion of the improvements made to spectral-domain optical coherence phase microscopy (SD-OCPM) to enable dynamic live cell imaging and the application of dynamic live cell SD-OCPM for morphological visualization of cheek epithelial cells and examination of functionally stimulated morphological changes in neurons. The work described in this dissertation demonstrates the versatility of OCT imaging technology to perform quantitative, label-free, high-speed and high-resolution imaging across spatiotemporal scales, enabling the examination of native dynamic tissue and cellular physiology.
Author : Gereon Hüttmann
Publisher :
ISBN 13 :
Total Pages : 49 pages
Book Rating : 4.:/5 (874 download)
Download or read book Optical Coherence Tomography (OCT) for High-speed Imaging and Therapy Control written by Gereon Hüttmann and published by . This book was released on 2013 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Zhongwei Zhi
Publisher :
ISBN 13 :
Total Pages : 135 pages
Book Rating : 4.:/5 (898 download)
Download or read book Development and Application of Multifunctional Optical Coherence Tomography written by Zhongwei Zhi and published by . This book was released on 2014 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microcirculation refers to the functions of capillaries and the neighboring lymphatic vessels. It plays a vital role in the pathophysiology of disorders in many clinical areas including cardiology, dermatology, neurology and ophthalmology, and so forth. It is crucial to develop imaging technologies that can provide both qualitative and quantitative information as to how microcirculation responds to certain injury and/or disease, and its treatment. Optical coherence tomography (OCT) is a non-invasive optical imaging technique for high-resolution cross-sectional imaging of specimens, with many applications in clinical medicine. Current state-of-the-art OCT systems operate in the Fourier domain, using either a broadband light source with a spectrometer, known as spectral domain OCT (SDOCT), or a rapidly tunable laser, known as swept source OCT (SSOCT). The current Fourier domain OCT systems have dramatically improvement in sensitivity, resolution and speed compared to time domain OCT. In addition to the improvement in the OCT system hardware, different methods for functional measurements of tissue beds have been developed and demonstrated. This includes but not limited to, i) Phase-resolved Doppler OCT for quantifying the blood flow, ii) OCT angiography for visualization of microvasculature, iii) Polarization sensitive OCT for measuring the intrinsic optical property/ birefringence of tissue, iv) spectroscopic OCT for measuring blood oxygenation, etc. Functional OCT can provide important clinical information that is not available in the typical intensity based structural OCT images. Among these functional OCT modalities, Doppler OCT and OCT angiography attract great interests as they show high capability for in vivo study of microvascular pathology. By analyzing the Doppler effect of a flowing particle on light frequency, Doppler OCT allows the quantification of the blood flow speed and blood flow rate. The most popular approach for Doppler OCT is achieved through analysis of the phase term in complex OCT signal which termed as Phase-resolved Doppler OCT. However, as limited by the phase noise and motion, Phase-resolved Doppler OCT can only be applied for relative large blood vessels, such as arterioles and venules. On the other hand, in order to visualize the microcirculation network, a number of strategies to enable better contrast of microvasculature components, which we termed OCT angiography, have been introduced during recent years. As a variation of Fourier domain OCT, optical microangiography (OMAG) is one of earliest proposed OCT angiography technique which is capable of generating 3D images of dynamic blood perfusion distribution within microcirculatory tissue beds. The OMAG algorithm works by separating the static and moving elements by high pass filtering on complex valued interferometric data after Fourier transform. Based on the conventional OMAG algorithm, we further developed ultra-high sensitive OMAG (UHS-OMAG) by switching the high-pass filtering from fast scan direction (adjacent A-lines within one B-frame) to slow scan direction (adjacent B-frames), which has a dramatically improved performance for capillary network imaging and analysis. Apart from the microvascular study with current available functional OCT for, visualization of the lymphatic system (lymph nodes and lymphatic vessels) plays a significant role in assessing patients with various malignancies and lymphedema. However, there is a lack of label-free and noninvasive method for lymphangiography. Hence, a cutting edge research to investigate the capability of OCT as a tool for non-invasive and label-free lymphangiography would be highly desired. The objective of my thesis is to develop a multiple-functional SDOCT system to image the microcirculation and quantify the several important parameters of microcirculation within microcirculatory tissue beds, and further apply it for pre-clinical research applications. The multifunctional OCT system provides modalities including structural OCT, OCT angiography, Doppler OCT and Optical lymphangiography, for multi-parametric study of tissue microstructure, blood vessel morphology, blood flow and lymphatic vessel all together. The thesis mainly focus on two parts: first, development of multi-functional OCT/optical microangiography (OMAG) system and methods for volumetric imaging of microvasculature and quantitative measurement of blood flow, and its application for pathological research in ophthalmology on rodent eye models; second, development of ultra-high resolution OCT system and algorithm for simultaneous label free imaging of blood and lymphatic vessel, and its application in wound healing study on mouse ear flap model. Objectives of my research are achieved through the following specific aims: Aim 1: Improve the sensitivity of OMAG for microvasculature imaging; perform volumetric and quantitative imaging of vasculature with combined OMAG and Phase-resolved Doppler OCT for in vivo study of vascular physiology. Aim 2: Develop high speed high resolution OCT system and method for rodent eye imaging. Apply the combined OMAG and Phase-resolved Doppler OCT approach to investigate the impact of elevated intraocular pressure on retinal, choroidal and optic nerve head blood flow in rat eye model, which aids to the better understanding of the mechanism and development of glaucoma. Aim 3: Apply the developed OCT system and ultra-high sensitive OMAG algorithm for noninvasive imaging of retinal morphology and microvasculature in obese mice, which may play an important role in early diagnosis of Diabetic retinopathy. Aim 4: Developing an ultra-high resolution SDOCT system using broadband Supercontinuum light source to achieve ultra-high resolution microvasculature imaging of biological tissue. Aim 5: Develop methods for simultaneous label free optical imaging of blood and lymphatic vessel and demonstrate its capability by monitoring the blood and lymph response to wound healing on mouse ear pinna model.
Author : Wolfgang Drexler
Publisher : Springer Verlag
ISBN 13 : 9783540775492
Total Pages : 1346 pages
Book Rating : 4.7/5 (754 download)
Download or read book Optical Coherence Tomography written by Wolfgang Drexler and published by Springer Verlag. This book was released on 2008 with total page 1346 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces optical coherence tomography, a high resolution imaging technique that enables non-invasive in vivo cross-sectional imaging of biological tissue. Covers optical and technological consderations as well biomedical and clinical perspectives.
