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 ...

Biological functions rely on microvasculature to deliver oxygen and nutrients and carry away metabolic waste. Measuring microvascular oxygen saturation (sO2), the fraction of oxygensaturated hemoglobin relative to total hemoglobin (unsaturated + saturated) in the blood, can assess tissue oxygenation and provide insights into tissue metabolism, inflammation, and oxygen-related pathologies. Several major diseases, such as cancer, diabetes mellitus, cardiovascular diseases, hypertension, chronic kidney disease, and neurodegenerative diseases, are related to local microvascular sO2. Therefore, it is of crucial importance to demonstrate an accurate and reliable method to measure microvascular sO2 for early diagnosis, monitoring disease progression, and evaluating treatments of oxygen metabolism ...

Optical Coherence Tomography (OCT) is an interferometric imaging modality that can visualize biological microstructure via cross-sectional images. OCT can construct 3D image data and produce a concise summary of the scanned objects. Because of the non-invasiveness and swift diagnostic procedure, OCT becomes a high potential technology for the real-time surgery guidance. Machine learning algorithms have been widely applied and investigated for automatic medical image analysis. This research proposes two deep learning models for OCT human tissue image classification. Based on the inception module structure, a deep dilated depthwise separable convolution neural network (DDSCN) model is proposed to combine the strength ...

Yongyang Huang received his B.S. degree in Physics at Peking University in July 2013. Since September 2013, he has been a Ph.D student in the Department of Electrical & Computer Engineering (ECE) in Lehigh University. His research area is focused on optical coherence tomography (OCT) and its applications in biomedical imaging.

This paper serves as a detailed overview of the software developed for the Falloposcope endoscope being developed by the Jennifer Barton Optics Tissue Laboratory. The Falloposcope is designed for a screening procedure for early detection of ovarian cancer in the fallopian tubes. The software controls a charge-coupled device (CCD) camera to perform reflectance and fluorescence imaging, which serves to navigate the endoscope to the fallopian tubes and surveil suspicious tissue regions. It also controls a swept source optical coherence tomography (SS-OCT) imaging system to provide high resolution, cross-sectional tomographic images of these tissue regions. CCD imaging is performed using a ...

The goal of this dissertation is to develop multimodal light scattering techniques using optical coherence tomography (OCT) to improve clinical diagnosis. OCT is a noninvasive optical imaging technique that utilizes low coherence interferometry to detect reflected and scattered light from a sample to produce depth resolved images. OCT is an emerging technology for a wide range of biomedical applications, with its largest impact in the field of ophthalmology to assess retinal morphology and abnormalities. Due to its excellent axial resolution, OCT has been often jointly used with a variety of other optical techniques in multimodal platforms for enhanced characterization of ...

Background: Visual perceptual impairments are well established in schizophrenia, ranging from deficits in basic visual discrimination to abnormalities in higher-level visual integration. Recent research has identified thinning o f retinal layers in individuals with schizophrenia, which may contribute to visual dysfunction. This study utilized optical coherence tomography to examine retinal integrity in individuals with schizophrenia, and investigated the contributions of retinal structure to low- and higher-level visual functions in schizophrenia. Methods: Participants were 12. individuals with schizophrenia-spectrum disorders and 12 age-matched healthy controls. Optical coherence tomography was utilized to obtain measurements for the retinal nerve fiber layer (RNFL), ganglion cell ...

In recent years, the importance of blood flow distribution has been highlighted in a wide range of diseases that involve the cerebral microvasculature. Specifically, microvascular heterogeneity, related to the non-uniform distribution of blood flow through the microvasculature, is an important parameter that is critical to the efficacy of oxygen extraction. As increased heterogeneity may lead to oxygen insufficiency, even with blood flow above ischemic levels, heterogeneity may be an important biomarker for understanding disease progression. However, current methods of quantifying microvascular heterogeneity over large microvascular networks that extend deep into biological tissue (such as the cerebral cortical microvasculature) are limited ...

Colorectal cancer (CRC) remains the second deadliest cancer in the United States, despite steady reduction in mortality rate over the last three decades. Colonoscopy is the gold-standard screening modality with high sensitivity and specificity to mature polyps. However, the miss rate for small (< 5 mm) lesions is estimated to be as high as 26%. Because the five-year survival rate for CRC detected at the local stage is 90%, there is a clear need for a screening procedure that is sensitive to these small lesions. Optical coherence tomography (OCT) has become a major biomedical imaging modality since its invention in 1991 ...

Recent advances in Optical Coherence Tomography (OCT) have enabled wide ranges of attractive applications, including characterization of biological tissues, morphological tracking, intravascular imaging, developmental biology and in functional spectroscopic aspects. Neural activity has been studied using optical methods in the past few decades. The use of light to probe neural activity allows outstanding resolution, and the possibility for simultaneous measurement from a range of targeted locations without physical contact with the tissue. Optically detectable signals, such as transient changes with phase and backscattered light intensity, are captured using spectral-domain OCT system. In this dissertation, a fundamental introduction to polarizationmaintaining fiber-based ...

The human eye is an organ that detects light from the environment and translates it into vision with the help of the brain. Eye health is critical to our daily life, such as working, reading, driving, sporting, and communicating with people. Malfunction of the eye can cause eye discomfort and clinical depressions, impair the patients’ independence, and compromise quality of life. For this reason, there is a broad range of interests in the field of eye research for better understanding of the eye that could help in early diagnosis and treatment of the prevalence eye diseases and benefit an increasing ...

Ophthalmic microsurgery is one of the most commonly performed surgical procedures in the world and it necessitates precise three-dimensional manipulation of tissue at submillimeter spatial scales. As a result, ophthalmic surgeons require an operating microscope to perform surgery and to asses alterations to the tissue. Unfortunately, modern operating microscopes provide a limited en face perspective of the three-dimensional surgical field, and surgeons must infer depth information using stereoscopy and cannot directly visualize subsurface anatomy. These limitations may compromise the surgeon’s ability to maneuver instruments axially and to comprehensively evaluate the three-dimensional tissue structure. Optical coherence tomography (OCT) is a ...

Over the past two decades, optical coherence tomography (OCT) has been successfully applied to various fields of biomedical researching and clinical studies, including cardiology, urology, dermatology, dentistry, oncology, and most successfully, ophthalmology. This dissertation seeks to extend the current OCT practice, which is still largely morphology-based, into a new dimension, functional analysis of metabolic activities in vivo. More specifically, the investigation is focused on retrieving blood oxygen saturation (sO2) using intrinsic hemoglobin optical absorption contrast. Most mammalian cells rely on aerobic respiration to support cellular function, which means they consume oxygen to create adenosine triphosphate (ATP). Metabolic rate of oxygen ...

Human vision starts when photoreceptors collect and respond to light. Photoreceptors do not function in isolation though, but share close interdependence with neighboring photoreceptors and underlying retinal pigment epithelium (RPE) cells. These cellular interactions are essential for normal function of the photoreceptor-RPE complex, but methods to assess these in the living human eye are limited. One approach that has gained increased promise is highresolution retinal imaging that has undergone tremendous technological advances over the last two decades to probe the living retina at the cellular level. Pivotal in these advances has been adaptive optics (AO) and optical coherence tomography (OCT ...

Optical Coherence Tomography (OCT) is an imaging tool that performs micronresolution, non-invasive, cross-sectional imaging by measuring the echoes of backscattered light. In this thesis, a custom-designed polarization-sensitive OCT (PS-OCT) system is discussed, which is implemented in using plasmonic gold nanorods (GNRs) as diffusion probes. PS-OCT imaging is undertaken in Newtonian fluids and validation of rotational and translational diffusion of GNRs with the Stokes-Einstein relation is presented via analysis of the autocorrelations of the OCT signals. Diffusion of GNRs in non-Newtonian fluids is also studied and the frequency-dependent viscoelasticity is also explored using generalized Stokes-Einstein relation. Furthermore, diffusion of GNRs in ...

Fourier domain optical coherence tomography (FD-OCT) is a high-speed, highresolution, and noninvasive imaging technique that can obtain cross-sectional images of light scattering medium, such as biomedical tissues. In this thesis, I report three novel methods in FD-OCT technique including common-path endoscopic FD-OCT, streakmode FD-OCT, and Doppler streak-mode FD-OCT. Finally, I apply the streak mode FDOCT to ultrahigh-speed, noninvasive, live imaging of embryonic chick hearts. An extension of conventional FD-OCT technique is endoscopic FD-OCT, which can access internal organs by utilizing a miniaturized catheter design. However, its image signal suffers from the bending of the endoscopic catheter. To address this problem ...