WorldWideScience

Sample records for saggital optical tomography

  1. Dental Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Kun-Feng Lin

    2013-07-01

    Full Text Available This review paper describes the applications of dental optical coherence tomography (OCT in oral tissue images, caries, periodontal disease and oral cancer. The background of OCT, including basic theory, system setup, light sources, spatial resolution and system limitations, is provided. The comparisons between OCT and other clinical oral diagnostic methods are also discussed.

  2. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Andersen, Peter E.

    2015-01-01

    Optical coherence tomography (OCT) is a noninvasive imaging technique that provides real-time two- and three-dimensional images of scattering samples with micrometer resolution. Mapping the local reflectivity, OCT visualizes the morphology of the sample, in real time or at video rate. In addition...

  3. Optical Tomography in Combustion

    DEFF Research Database (Denmark)

    Evseev, Vadim

    spectral measurements at several line-of-sights with a view to applications for tomographic measurements on full-scale industrial combustion systems. The system was successfully applied on industrial scale for simultaneous fast exhaust gas temperature measurements in the three optical ports of the exhaust......D project, it was also important to investigate the spectral properties of major combustion species such as carbon dioxide and carbon monoxide in the infrared range at high temperatures to provide the theoretical background for the development of the optical tomography methods. The new software....... JQSRT 113 (2012) 2222, 10.1016/j.jqsrt.2012.07.015] included in the PhD thesis as an attachment. The knowledge and experience gained in the PhD project is the first important step towards introducing the advanced optical tomography methods of combustion diagnostics developed in the project to future...

  4. Solar tomography adaptive optics.

    Science.gov (United States)

    Ren, Deqing; Zhu, Yongtian; Zhang, Xi; Dou, Jiangpei; Zhao, Gang

    2014-03-10

    Conventional solar adaptive optics uses one deformable mirror (DM) and one guide star for wave-front sensing, which seriously limits high-resolution imaging over a large field of view (FOV). Recent progress toward multiconjugate adaptive optics indicates that atmosphere turbulence induced wave-front distortion at different altitudes can be reconstructed by using multiple guide stars. To maximize the performance over a large FOV, we propose a solar tomography adaptive optics (TAO) system that uses tomographic wave-front information and uses one DM. We show that by fully taking advantage of the knowledge of three-dimensional wave-front distribution, a classical solar adaptive optics with one DM can provide an extra performance gain for high-resolution imaging over a large FOV in the near infrared. The TAO will allow existing one-deformable-mirror solar adaptive optics to deliver better performance over a large FOV for high-resolution magnetic field investigation, where solar activities occur in a two-dimensional field up to 60'', and where the near infrared is superior to the visible in terms of magnetic field sensitivity.

  5. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Fercher, A.F.; Andersen, Peter E.

    2017-01-01

    Optical coherence tomography (OCT) is a technique that is used to peer inside a body noninvasively. Tissue structure defined by tissue absorption and scattering coefficients, and the speed of blood flow, are derived from the characteristics of light remitted by the body. Singly backscattered light...... used in the medical field, in particular, in ophthalmology. Owing to the high transmissivity of ocular media, the depth penetration is considerable. Corresponding applications in dermatology are somewhat hindered by the strong scattering of epidermic tissue (μs ≈ 102 mm−1). As OCT provides images...... for intraoperative monitoring, and in microsurgical intervention. Optical biopsy based on OCT also provides diagnostic information by differentiating the architectural morphology of urological tissue, gastrointestinal tissue, and respiratory tissue....

  6. Amplified Dispersive Optical Tomography

    CERN Document Server

    Goda, Keisuke; Jalali, Bahram

    2008-01-01

    Optical coherence tomography (OCT) has proven to be a powerful technique for studying tissue morphology in ophthalmology, cardiology, and endomicroscopy. Its performance is limited by the fundamental trade-off between the imaging sensitivity and acquisition speed -- a predicament common in virtually all imaging systems. In this paper, we circumvent this limit by using distributed Raman post-amplification of the reflection from the sample. We combine the amplification with simultaneously performed dispersive Fourier transformation, a process that maps the optical spectrum into an easily measured time-domain waveform. The Raman amplification enables measurement of weak signals which are otherwise buried in noise. It extends the depth range without sacrificing the acquisition speed or causing damage to the sample. As proof of concept, single-shot imaging with 15 dB improvement in sensitivity at an axial scan rate of 36.6 MHz is demonstrated.

  7. Optical Coherence Tomography

    Science.gov (United States)

    Huang, David

    Optical coherence tomography (OCT) is a new method for noninvasive cross-sectional imaging in biological systems. In OCT, the longitudinal locations of tissue structures are determined by measuring the time-of-flight delays of light backscattered from these structures. The optical delays are measured by low coherence interferometry. Information on lateral position is provided by transverse scanning of the probe beam. The two dimensional map of optical scattering from internal tissue microstructures is then represented in a false-color or grayscale image. OCT is the optical analog of ultrasonic pulse-echo imaging, but with greatly improved spatial resolutions (a few microns). This thesis describes the development of this new high resolution tomographic imaging technology and the demonstration of its use in a variety of tissues under both in vitro and in vivo conditions. In vitro OCT ranging and imaging studies were performed using human ocular and arterial tissues, two clinically relevant examples of transparent and turbid media, respectively. In the anterior eye, precise measurements of cornea and anterior chamber dimensions were made. In the arterial specimens, the differentiation between fatty -calcified and fibromuscular tissues was demonstrated. In vivo OCT imaging in the retina and optic nerve head in human subjects was also performed. The delineation of retinal layers, which has not been possible with other noninvasive imaging techniques, is demonstrated in these OCT images. OCT has high spatial resolution but limited penetration into turbid tissue. It has potential for diagnostic applications where high resolution is needed and optical access is available, such as in the eye, skin, surgically exposed tissues, and surfaces that can be reached by various catheters and endoscopic probes. In particular, the measurement of fine retinal structures promises improvements in the diagnosis and management of glaucoma, macular edema and other vitreo-retinal diseases

  8. Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Pier Alberto Testoni

    2007-01-01

    Full Text Available Optical coherence tomography (OCT is an optical imaging modality that performs high-resolution, cross-sectional, subsurface tomographic imaging of the microstructure of tissues. The physical principle of OCT is similar to that of B-mode ultrasound imaging, except that it uses infrared light waves rather than acoustic waves. The in vivo resolution is 10–25 times better (about 10 µm than with high-frequency ultrasound imaging, but the depth of penetration is limited to 1–3 mm, depending on tissue structure, depth of focus of the probe used, and pressure applied to the tissue surface. In the last decade, OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice, including the gastrointestinal tract and pancreatico-biliary ductal system. OCT imaging from the gastrointestinal tract can be done in humans by using narrow-diameter, catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope, for investigating the epithelial structure of the gastrointestinal tract, or a side-view endoscope, inside a standard transparent ERCP (endoscopic retrograde cholangiopancreatography catheter, for investigating the pancreatico-biliary ductal system. The esophagus and esophagogastric junction have been the most widely investigated organs so far; more recently, duodenum, colon, and the pancreatico-biliary ductal system have also been extensively investigated. OCT imaging of the gastrointestinal wall structure is characterized by a multiple-layer architecture that permits an accurate evaluation of the mucosa, lamina propria, muscularis mucosae, and part of the submucosa. The technique may therefore be used to identify preneoplastic conditions of the gastrointestinal tract, such as Barrett's epithelium and dysplasia, and evaluate the depth of penetration of early-stage neoplastic lesions. OCT imaging

  9. Optical tomography with structured illumination.

    Science.gov (United States)

    Lukic, Vladimir; Markel, Vadim A; Schotland, John C

    2009-04-01

    We consider the image reconstruction problem for optical tomography with structured illumination. A fast image reconstruction algorithm is proposed that reduces the required number of measurements of the optical field compared to methods that utilize point-source illumination. The results are illustrated with numerical simulations.

  10. Hyperspectral optical diffraction tomography

    CERN Document Server

    Jung, JaeHwang; Yoon, Jonghee; Park, YongKeun

    2015-01-01

    Here, we present a novel microscopic technique for measuring wavelength-dependent three-dimensional (3-D) distributions of the refractive indices (RIs) of microscopic samples in the visible wavelengths. Employing 3-D quantitative phase microscopy techniques with a wavelength-swept source, 3-D RI tomograms were obtained in the range of 450 - 700 nm with a spectral resolution of a few nanometers. The capability of the technique was demonstrated by measuring the hyperspectral 3-D RI tomograms of polystyrene beads, human red blood cells, and hepatocytes. The results demonstrate the potential for label-free molecular specific 3-D tomography of biological samples.

  11. Integrated-optics-based optical coherence tomography

    NARCIS (Netherlands)

    Nguyen, D.V.

    2013-01-01

    Optical coherence tomography (OCT) is a high resolution, imaging technique that has developed over the last 20 years from a complicated laboratory setup into a ready-to-use commercially available device. Instead of using electronic time gating as being used by ultrasound (US) imaging, in OCT, the op

  12. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Mogensen, Mette; Themstrup, Lotte; Banzhaf, Christina;

    2014-01-01

    as the optical analogue to ultrasound. The inherent safety of the technology allows for in vivo use of OCT in patients. The main strength of OCT is the depth resolution. In dermatology, most OCT research has turned on non-melanoma skin cancer (NMSC) and non-invasive monitoring of morphological changes...... tissue after therapy. The OCT images provide an advantageous combination of resolution and penetration depth, but specific studies of diagnostic sensitivity and specificity in dermatology are sparse. In order to improve OCT image quality and expand the potential of OCT, technical developments...... are necessary. It is suggested that the technology will be of particular interest to the routine follow-up of patients undergoing non-invasive therapy of malignant or premalignant keratinocyte tumours. It is speculated that the continued technological development can propel the method to a greater level...

  13. In Vivo Diffuse Optical Tomography and Fluorescence Molecular Tomography

    Directory of Open Access Journals (Sweden)

    Mingze Li

    2010-01-01

    Full Text Available Diffuse optical tomography (DOT and fluorescence molecular tomography (FMT are two attractive imaging techniques for in vivo physiological and psychological research. They have distinct advantages such as non-invasiveness, non-ionizing radiation, high sensitivity and longitudinal monitoring. This paper reviews the key components of DOT and FMT. Light propagation model, mathematical reconstruction algorithm, imaging instrumentation and medical applications are included. Future challenges and perspective on optical tomography are discussed.

  14. Optical Coherence Tomography: Advanced Modeling

    DEFF Research Database (Denmark)

    Andersen, Peter E.; Thrane, Lars; Yura, Harold T.;

    2013-01-01

    Analytical and numerical models for describing and understanding the light propagation in samples imaged by optical coherence tomography (OCT) systems are presented. An analytical model for calculating the OCT signal based on the extended Huygens-Fresnel principle valid both for the single......- and multiple-scattering regimes is derived. An advanced Monte Carlo model for calculating the OCT signal is also derived, and the validity of this model is shown through a mathematical proof based on the extended Huygens-Fresnel principle. From the analytical model, an algorithm for enhancing OCT images...... is developed, the so-called true-reflection algorithm in which the OCT signal may be corrected for the attenuation caused by scattering. The algorithm is verified experimentally and by using the Monte Carlo model as a numerical tissue phantom. Applications of extraction of optical properties from tissue...

  15. Optical Microangiography Based on Optical Coherence Tomography

    Science.gov (United States)

    Reif, Roberto; Wang, Ruikang K.

    Proper homeostasis regulation of in vivo biological systems requires microvascular blood perfusion, which is the process of delivering blood into the tissue's capillary beds. Abnormal tissue vascularization has been associated with various diseases such as cancer, diabetes, neurological disorders, wounds, and inflammation. Understanding the changes in the vascular network or microangiography will have an important role in determining the causes and developing potential treatments for these diseases. Optical coherence tomography (OCT) is a noninvasive method for imaging three-dimensional biological tissues with high resolution (~10 µm) and without requiring the use of contrast agents. In this chapter we review several techniques for using OCT to determine blood flow velocities and the vessel morphology (optical microangiography). Different techniques will be discussed with a brief explanation of their limitations. Also, methods for quantifying these images are presented, as well as the depiction of several applications.

  16. Anterior Segment Tomography with the Cirrus Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Eduardo B. Rodrigues

    2012-01-01

    Full Text Available Optical coherence tomography (OCT is an optical acquisition method to examine biological tissues. In recent years, OCT has become an important imaging technology used in diagnosing and following macular pathologies. Further development enabled application of optical coherence tomography in evaluation of the integrity of the nerve fiber layer, optic nerve cupping, anterior chamber angle, or corneal topography. In this manuscript we overview the use of OCT in the clinical practice to enable corneal, iris, ciliary body, and angle evaluation and diagnostics.

  17. Imaging granulomatous lesions with optical coherence tomography

    DEFF Research Database (Denmark)

    Banzhaf, Christina; Jemec, Gregor B E

    2012-01-01

    To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors.......To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors....

  18. Optical coherence tomography in dermatology

    Science.gov (United States)

    Sattler, Elke; Kästle, Raphaela; Welzel, Julia

    2013-06-01

    Optical coherence tomography (OCT) is a noninvasive diagnostic method that offers a view into the superficial layers of the skin in vivo in real-time. An infrared broadband light source allows the investigation of skin architecture and changes up to a depth of 1 to 2 mm with a resolution between 15 and 3 μm, depending on the system used. Thus OCT enables evaluation of skin lesions, especially nonmelanoma skin cancers and inflammatory diseases, quantification of skin changes, visualization of parasitic infestations, and examination of other indications such as the investigation of nails. OCT provides a quick and useful diagnostic imaging technique for a number of clinical questions and is a valuable addition or complement to other noninvasive imaging tools such as dermoscopy, high-frequency ultrasound, and confocal laser scan microscopy.

  19. Optical Coherence Tomography (OCT) in ophthalmology: introduction.

    Science.gov (United States)

    Fujimoto, James G; Drexler, Wolfgang; Schuman, Joel S; Hitzenberger, Christoph K

    2009-03-02

    The Optical Society (OSA) is pleased to present this special issue of Optics Express on "Optical Coherence Tomography (OCT) in Ophthalmology" as part of the new Interactive Science Publishing (ISP) project. The project is being performed in collaboration with the National Library of Medicine and represents a new paradigm for the publication of digital image and large dataset information.

  20. Second-harmonic optical coherence tomography

    Science.gov (United States)

    Jiang, Yi; Tomov, Ivan; Wang, Yimin; Chen, Zhongping

    2004-05-01

    Second-harmonic optical coherence tomography, which uses coherence gating of second-order nonlinear optical responses of biological tissues for imaging, is described and demonstrated. Femtosecond laser pulses were used to excite second-harmonic waves from collagen harvested from rat tail tendon and a reference nonlinear crystal. Second-harmonic interference fringe signals were detected and used for image construction. Because of the strong dependence of second-harmonic generation on molecular and tissue structures, this technique imparts contrast and resolution enhancement to conventional optical coherence tomography.

  1. Optical coherence tomography in late solar retinopathy

    Directory of Open Access Journals (Sweden)

    Janković Aleksandar

    2011-01-01

    Full Text Available Introduction. Solar retinopathy refers to retinal injury induced by direct or indirect solar viewing. Case report. We presented a patient who had observed partial solar eclipse 51 year before. He had bilaterally decreased vision and scar of the macular region at the time of presentation. The basic diagnostic tool applied in the presented patient, optical coherence tomography, showed hyporeflexivity of the outer retina in the segment of retinal pigment epithelialphotoreceptors complex with atrophy and thinning of the foveolar region. Conclusion. Optical coherence tomography is a powerful, non-invasive diagnostic tool which can ease the diagnosis and estimate the level and nature of the macular region damage.

  2. Optical coherence tomography: Technique and applications

    DEFF Research Database (Denmark)

    Thomsen, Jakob Borup; Sander, Birgit; Mogensen, Mette;

    2009-01-01

    Optical coherence tomography (OCT) is a noninvasive optical imaging modality providing real-time video rate images in two and three dimensions of biological tissues with micrometer resolution. OCT fills the gap between ultrasound and confocal microscopy, since it has a higher resolution than ultr...... of retinal diseases. The potential of OCT in many other applications is currently being explored, such as in developmental biology, skin cancer diagnostics, vulnerable plaque detection in cardiology, esophageal diagnostics and a number of other applications within oncology....

  3. Reconstructions in ultrasound modulated optical tomography

    KAUST Repository

    Allmaras, Moritz

    2011-01-01

    We introduce a mathematical model for ultrasound modulated optical tomography and present a simple reconstruction scheme for recovering the spatially varying optical absorption coefficient from scanning measurements with narrowly focused ultrasound signals. Computational results for this model show that the reconstruction of sharp features of the absorption coefficient is possible. A formal linearization of the model leads to an equation with a Fredholm operator, which explains the stability observed in our numerical experiments. © de Gruyter 2011.

  4. Optical tomography: forward and inverse problems

    CERN Document Server

    Arridge, Simon

    2009-01-01

    This paper is a review of recent mathematical and computational advances in optical tomography. We discuss the physical foundations of forward models for light propagation on microscopic, mesoscopic and macroscopic scales. We also consider direct and numerical approaches to the inverse problems that arise at each of these scales. Finally, we outline future directions and open problems in the field.

  5. Optical Coherence Tomography for Material Characterization

    NARCIS (Netherlands)

    Liu, P.

    2014-01-01

    Optical coherence tomography (OCT) is a non-invasive, contactless and high resolution imaging method, which allows the reconstruction of two or three dimensional depth-resolved images in turbid media. In the past 20 years, OCT has been extensively developed in the field of biomedical diagnostics, wh

  6. Functional optical coherence tomography of pigmented lesions

    NARCIS (Netherlands)

    Wessels, R.; Bruin, de D.M.; Relyveld, G.N.; Faber, D.J.; Vincent, A.D.; Sanders, J.; Leeuwen, van T.G.; Ruers, T.J.M.

    2015-01-01

    Background Cutaneous melanomas are diagnosed worldwide in 231 130 patients per year. The sensitivity and specificity of melanoma diagnosis expresses the need for an additional diagnostic method. Optical coherence tomography (OCT) has shown that it allows morphological (qualitative) description of im

  7. Gabor fusion master slave optical coherence tomography

    DEFF Research Database (Denmark)

    Cernat, Ramona; Bradu, Adrian; Israelsen, Niels Møller

    2017-01-01

    This paper describes the application of the Gabor filtering protocol to a Master/Slave (MS) swept source optical coherence tomography (SS)-OCT system at 1300 nm. The MS-OCT system delivers information from selected depths, a property that allows operation similar to that of a time domain OCT syst...

  8. Optical coherence tomography in conjunction with bronchoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Ascedio Jose; Takimura, Celso Kiyochi; Lemos Neto, Pedro Alves; Figueiredo, Viviane Rossi, E-mail: ascedio@gmail.com [Servico de Endoscopia Respiratoria, Hospital das Clinicas, Universidade de Sao Paulo (FM/USP), SP (Brazil)

    2012-07-01

    To evaluate the feasibility of and the potential for using optical coherence tomography in conjunction with conventional bronchoscopy in the evaluation of the airways. Methods: This was a pilot study based on an ex vivo experimental model involving three animals: one adult New Zealand rabbit and two Landrace pigs. An optical coherence tomography imaging catheter was inserted through the working channel of a flexible bronchoscope in order to reach the distal trachea of the animals. Images of the walls of the trachea were systematically taken along its entire length, from the distal to the proximal portion. Results: The imaging catheter was easily adapted to the working channel of the bronchoscope. High-resolution images of cross sections of the trachea were taken in real time, precisely delineating microstructures, such as the epithelium, submucosa, and cartilage, as well as the adventitia of the anterior and lateral tracheal walls. The corresponding layers of the epithelium, mucosa, and cartilage were clearly differentiated. The mucosa, submucosa, and trachealis muscle were clearly identified in the posterior wall. Conclusions: It is feasible to use an optical coherence tomography imaging catheter in combination with a flexible bronchoscope. Optical coherence tomography produces high resolution images that reveal the microanatomy of the trachea, including structures that are typically seen only on images produced by conventional histology. (author)

  9. Homodyne en face optical coherence tomography

    OpenAIRE

    Yaqoob, Zahid; Fingler, Jeff; Heng, Xin; Yang, Changhuei

    2006-01-01

    We demonstrate, for what we believe to be the first time, the use of a 3×3 fiber-optic coupler to realize a homodyne optical coherence tomography (OCT) system for en face imaging of highly scattering tissues and turbid media. The homodyne OCT setup exploits the inherent phase shifts between different output ports of a 3×3 fiber-optic coupler to extract amplitude information of a sample. Our homodyne en face OCT system features a measured resolution of 14 μm axially and 9.4 μm laterally with a...

  10. Single-Scattering Optical Tomography

    CERN Document Server

    Markel, V A; Markel, Vadim A.; Schotland, John C.

    2007-01-01

    We describe a novel tomographic imaging modality. The proposed technique utilizes visible or near-infrared light as a tissue probe in the ``mesoscopic'' scattering regime when the tissue layer exhibits sufficiently strong scattering so that its direct visual inspection is not possible, yet transmitted and reflected light are not diffuse. The forward model for light propagation in tissues is based on the scattering-order expansion of the radiative transport equation Green's function. The associated inverse problem is similar to the problem of inverting the Radon transform of x-ray tomography, except that the ray integrals are evaluated not along straight lines but along broken rays. As a result, the method does not require rotating the imaging device around the sample and taking multiple projections and, therefore, can be used in backscattering. An algebraic image reconstruction algorithm is numerically implemented using computer-generated data. An analytic image reconstruction formula analogous to the filtere...

  11. Optical tomography of the neonatal brain

    Energy Technology Data Exchange (ETDEWEB)

    Hebden, Jeremy C. [University College London, Department of Medical Physics and Bioengineering, London (United Kingdom); Austin, Topun [University College London, Department of Paediatrics and Child Health, London (United Kingdom)

    2007-11-15

    A new method of assessing neurological function and pathology in the newborn infant is being developed based on the transmission of near-infrared light across the brain. Absorption by blood over a range of wavelengths reveals a strong dependency on oxygenation status, and measurements of transmitted light enable the spatial variation in the concentrations of the oxygenated and de-oxygenated forms of hemoglobin to be derived. Optical tomography has so far provided static three-dimensional maps of blood volume and oxygenation as well as dynamic images revealing the brain's response to sensory stimulation and global hemodynamic changes. The imaging modality is being developed as a safe and non-invasive tool that can be utilized at the cotside in intensive care. Optical tomography of the healthy infant brain is also providing a means of studying neurophysiological processes during early development and the potential consequences of prematurity. (orig.)

  12. Optical tomography system for laboratory turbulence measurements

    Science.gov (United States)

    McMackin, Lenore J.; Pierson, Robert E.; Hugo, Ronald J.; Truman, C. Randall

    1998-10-01

    We describe the design and operation of a high speed optical tomography system for measuring 2D images of a dynamic phase object at a rate of 5 kHz. Data from a set of eight Hartmann wavefront sensors is back-projected to produce phase images showing the details of the inner structure of a heated air flow. Series of reconstructions at different downstream locations illustrate the development of flow structure and the effect of acoustic flow forcing.

  13. Turbidity Measurement Using An Optical Tomography System

    OpenAIRE

    Sallehuddin Bin Ibrahim

    2013-01-01

    Turbidity is used to describe water quality and it can be caused by the presence of suspended particles and organic matter such as algae, clay and silt. The measurement of turbidity level of water is vital to domestic water supplies since it is related to public health and water treatment process. This paper presents an investigation on an optical tomography system to estimate the turbidity level in a sample of water. The optical sensors consist of infrared light-emitting diodes (LED) as tran...

  14. Optical coherence tomography findings of quinine poisoning

    Directory of Open Access Journals (Sweden)

    John Christoforidis

    2011-01-01

    Full Text Available John Christoforidis, Robert Ricketts, Theodore Loizos, Susie ChangThe Ohio State University College of Medicine, Columbus, OH, USAPurpose: To report a case of acute quinine poisoning, document acute and chronic macular changes with optical coherence tomography imaging and fluorescein angiography (FA, and to review the literature on ocular toxicity of quinine.Methods: A 32-year-old white female presented to our Emergency Department after ingesting over 7.5 g of quinine. She underwent a complete ophthalmologic examination, fluorescein angiography, Stratus time-domain optical coherence tomography (OCT, and electroretinography at 72 hours and 15 months postingestion. Stratus time-domain and Cirrus spectral-domain OCT, fundus autofluorescence, and FA were obtained at 28 months postingestion.Results: Fluorescein angiography at 72 hours postingestion revealed normal filling times and vasculature. OCT showed marked thickening of the inner retina bilaterally. At 15 and 28 months follow-up, fundus photography and fluorescein angiography demonstrated optic nerve pallor, severely attenuated retinal vessels while OCT showed inner retinal atrophy. Fundus autofluorescence did not reveal any retinal pigmentary abnormalities.Conclusions: Quinine toxicity as seen by OCT reveals increased thickness with inner retinal hyperreflectivity acutely with development of significant retinal atrophy in the long-term. Fundus autofluorescence reveals an intact retinal pigment epithelial layer at 28 months. These findings suggest that quinine poisoning may produce a direct toxic effect on the inner retina in the acute phase resulting in long-term retinal atrophy.Keywords: retinal, optical coherence tomography, quinine toxicity 

  15. MEMS scanning micromirror for optical coherence tomography.

    Science.gov (United States)

    Strathman, Matthew; Liu, Yunbo; Keeler, Ethan G; Song, Mingli; Baran, Utku; Xi, Jiefeng; Sun, Ming-Ting; Wang, Ruikang; Li, Xingde; Lin, Lih Y

    2015-01-01

    This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique.

  16. Optical Coherence Tomography Angiography in Fovea Plana.

    Science.gov (United States)

    Dolz-Marco, Rosa; Phasukkijwatana, Nopasak; Sarraf, David; Freund, K Bailey

    2016-07-01

    Fovea plana is characterized by the anatomical absence of the foveal pit in eyes with normal visual function. The authors have analyzed three cases of idiopathic fovea plana with optical coherence tomography angiography (OCTA). As previously reported, the authors found the absence of a foveal avascular zone in all cases with OCTA; however, a preserved fusion of both the superficial and the deep capillary plexuses was found around the foveal center. This novel observation cannot be detected with conventional dye-based angiography, in which the deep capillary plexus is not visualized. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:670-673.].

  17. Optical coherence tomography investigations of ceramic lumineers

    Science.gov (United States)

    Fernandes, Luana O.; Graça, Natalia D. R. L.; Melo, Luciana S. A.; Silva, Claudio H. V.; Gomes, Anderson S. L.

    2016-02-01

    Lumineers are veneer laminates used as an alternative for aesthetic dental solutions of the highest quality, but the only current means of its performance assessment is visual inspection. The objective of this study was to use the Optical Coherence Tomography (OCT) technique working in spectral domain to analyze in vivo in a single patient, 14 lumineers 180 days after cementation. It was possible to observe images in various kinds of changes in the cementing line and the laminate. It was concluded that the OCT is an effective and promising method to clinical evaluation of the cementing line in lumineers.

  18. Adaptive optics optical coherence tomography for retina imaging

    Institute of Scientific and Technical Information of China (English)

    Guohua Shi; Yun Dai; Ling Wang; Zhihua Ding; Xuejun Rao; Yudong Zhang

    2008-01-01

    When optical coherence tomography (OCT) is used for human retina imaging, its transverse resolution is limited by the aberrations of human eyes. To overcome this disadvantage, a high resolution imaging system for living human retina, which consists of a time domain OCT system and a 37-elements adaptive optics (AO) system, has been developed. The AO closed loop rate is 20 frames per second, and the OCT has a 6.7-μm axial resolution. In this paper, this system is introduced and the high resolution imaging results for retina are presented.

  19. Fiber optic based optical coherence tomography (OCT) for dental applications

    Energy Technology Data Exchange (ETDEWEB)

    Everett, M. J., LLNL

    1998-06-02

    We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity We have produced, using this scanning device, in viva cross-sectional images of hard and soft dental tissues in human volunteers Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento-enamel junction, were visible in all the images The dento-enamel junction and the alveolar bone were identifiable in approximately two thirds of the images These images represent, to our knowledge, the first in viva OCT images of human dental tissue.

  20. Turbidity Measurement Using An Optical Tomography System

    Directory of Open Access Journals (Sweden)

    Sallehuddin Bin Ibrahim

    2013-10-01

    Full Text Available Turbidity is used to describe water quality and it can be caused by the presence of suspended particles and organic matter such as algae, clay and silt. The measurement of turbidity level of water is vital to domestic water supplies since it is related to public health and water treatment process. This paper presents an investigation on an optical tomography system to estimate the turbidity level in a sample of water. The optical sensors consist of infrared light-emitting diodes (LED as transmitters and photodiodes as the receivers where the projections of the sensors are designed in fan beam mode. The system was tested using a vertical flow pipe. The Independent Component Analysis (ICA method was used to display the concentration profile. Results obtained proved that the technique can provide the concentration profile representing the turbidity level of water.

  1. Optical Coherence Tomography Velocimetry with Complex Fluids

    Science.gov (United States)

    Malm, A.; Waigh, T. A.; Jaradat, S.; Tomlin, R.

    2015-04-01

    We present recent results obtained with an Optical Coherence Tomography Velocimetry technique. An optical interferometer measures the velocity of a sheared fluid at specific depths of the sample using the coherence length of the light source. The technique allows the dynamics of 3 pico liter volumes to be probed inside opaque complex fluids. In a study of opaque starch suspensions, classical bulk rheology experiments show non-linear shear thickening, whereas observations of the velocity profiles as a function of distance across the gap show Newtonian behavior. The ability of the technique to measure velocity fluctuations is also discussed for the case of polyacrylamide samples which were observed to display shear banding behavior. A relationship between the viscoelasticity of the sample and the size of the apparent fluctuations is observed.

  2. Near-Infrared Diffuse Optical Tomography

    Directory of Open Access Journals (Sweden)

    A. H. Hielscher

    2002-01-01

    Full Text Available Diffuse optical tomography (DOT is emerging as a viable new biomedical imaging modality. Using near-infrared (NIR light, this technique probes absorption as well as scattering properties of biological tissues. First commercial instruments are now available that allow users to obtain cross-sectional and volumetric views of various body parts. Currently, the main applications are brain, breast, limb, joint, and fluorescence/bioluminescence imaging. Although the spatial resolution is limited when compared with other imaging modalities, such as magnetic resonance imaging (MRI or X-ray computerized tomography (CT, DOT provides access to a variety of physiological parameters that otherwise are not accessible, including sub-second imaging of hemodynamics and other fast-changing processes. Furthermore, DOT can be realized in compact, portable instrumentation that allows for bedside monitoring at relatively low cost. In this paper, we present an overview of current state-of-the -art technology, including hardware and image-reconstruction algorithms, and focus on applications in brain and joint imaging. In addition, we present recent results of work on optical tomographic imaging in small animals.

  3. In vivo cellular visualization of the human retina using optical coherence tomography and adaptive optics

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, S S; Jones, S M; Chen, D C; Zawadzki, R J; Choi, S S; Laut, S P; Werner, J S

    2006-01-05

    Optical coherence tomography (OCT) sees the human retina sharply with adaptive optics. In vivo cellular visualization of the human retina at micrometer-scale resolution is possible by enhancing Fourier-domain optical-coherence tomography with adaptive optics, which compensate for the eye's optical aberrations.

  4. Optical Coherence Tomography in a Needle Format

    Science.gov (United States)

    Lorenser, Dirk; McLaughlin, Robert A.; Sampson, David D.

    In this chapter, we review the technology and applications of needle probes for optical coherence tomography (OCT). Needle probes are miniaturized fiber-optic probes that can be mounted inside hypodermic needles, allowing them to be inserted deep into the body during OCT imaging. This overcomes the very limited imaging depth of OCT of only 2-3 mm in biological tissue, enabling access to deep-tissue locations that are beyond the reach of free-space optical scan heads or catheters. This chapter provides an in-depth review of the current state-of-the art in needle probe technology, including optical design and fabrication, scan mechanisms (including three-dimensional scanning), and integration into OCT systems. It also provides an overview of emerging applications of this fascinating new imaging tool in areas such as cancer diagnosis, pulmonary imaging, imaging of the eye and imaging of the brain. Finally, two case studies are presented, illustrating needle-based OCT imaging in breast cancer and lungs.

  5. Optical coherence tomography technology and applications

    CERN Document Server

    Fujimoto, James

    2015-01-01

    Optical coherence tomography (OCT) is the optical analog of ultrasound imaging and is a powerful imaging technique that enables non-invasive, in vivo, high resolution, cross-sectional imaging in biological tissue.  Between 30 to 40 Million OCT imaging procedures are performed per year in ophthalmology.  The overall market is estimated at more than 0.5 Billion USD.  A new generation OCT technology was developed, dramatically increasing resolution and speed, achieving in vivo optical biopsy, i.e. the visualization of tissue architectural morphology in situ and in real time.  Functional extensions of OCT technology enable non-invasive, depth resolved functional assessment and imaging of tissue.  The book introduces OCT technology and applications not only from an optical and technological viewpoint, but also from the biomedical and clinical perspective. This second edition is widely extended and covers significantly more topics then the first edition of this book. The chapters are written leading intern...

  6. Optical tomography of the aurora and EISCAT

    Directory of Open Access Journals (Sweden)

    H. U. Frey

    Full Text Available Tomographic reconstruction of the three-dimensional auroral arc emission is used to obtain vertical and horizontal distributions of the optical auroral emission. Under the given experimental conditions with a very limited angular range and a small number of observers, algebraic reconstruction methods generally yield better results than transform techniques. Different algebraic reconstruction methods are tested with an auroral arc model and the best results are obtained with an iterative least-square method adapted from emission-computed tomography. The observation geometry used during a campaign in Norway in 1995 is tested with the arc model and root-mean-square errors, to be expected under the given geometrical conditions, are calculated. Although optimum geometry was not used, root-mean-square errors of less than 2% for the images and of the order of 30% for the distribution could be obtained. The method is applied to images from real observations. The correspondence of original pictures and projections of the reconstructed volume is discussed, and emission profiles along magnetic field lines through the three-dimensionally reconstructed arc are calibrated into electron density profiles with additional EISCAT measurements. Including a background profile and the temporal changes of the electron density due to recombination, good agreement can be obtained between measured profiles and the time-sequence of calculated profiles. These profiles are used to estimate the conductivity distribution in the vicinity of the EISCAT site. While the radar can only probe the ionosphere along the radar beam, the three-dimensional tomography enables conductivity estimates in a large area around the radar site.

    Key words. Tomography · Aurora · EISCAT · Ionosphere · Conductivity

  7. Diffuse Optical Tomography for Brain Imaging: Theory

    Science.gov (United States)

    Yuan, Zhen; Jiang, Huabei

    Diffuse optical tomography (DOT) is a noninvasive, nonionizing, and inexpensive imaging technique that uses near-infrared light to probe tissue optical properties. Regional variations in oxy- and deoxy-hemoglobin concentrations as well as blood flow and oxygen consumption can be imaged by monitoring spatiotemporal variations in the absorption spectra. For brain imaging, this provides DOT unique abilities to directly measure the hemodynamic, metabolic, and neuronal responses to cells (neurons), and tissue and organ activations with high temporal resolution and good tissue penetration. DOT can be used as a stand-alone modality or can be integrated with other imaging modalities such as fMRI/MRI, PET/CT, and EEG/MEG in studying neurophysiology and pathology. This book chapter serves as an introduction to the basic theory and principles of DOT for neuroimaging. It covers the major aspects of advances in neural optical imaging including mathematics, physics, chemistry, reconstruction algorithm, instrumentation, image-guided spectroscopy, neurovascular and neurometabolic coupling, and clinical applications.

  8. Nonlinear inversion schemes for fluorescence optical tomography.

    Science.gov (United States)

    Freiberger, Manuel; Egger, Herbert; Scharfetter, Hermann

    2010-11-01

    Fluorescence optical tomography is a non-invasive imaging modality that employs the absorption and re-emission of light by fluorescent dyes. The aim is to reconstruct the fluorophore distribution in a body from measurements of light intensities at the boundary. Due to the diffusive nature of light propagation in tissue, fluorescence tomography is a nonlinear and severely ill-posed problem, and some sort of regularization is required for a stable solution. In this paper we investigate reconstruction methods based on Tikhonov regularization with nonlinear penalty terms, namely total-variation regularization and a levelset-type method using a nonlinear parameterization of the unknown function. Moreover, we use the full threedimensional nonlinear forward model, which arises from the governing system of partial differential equations. We discuss the numerical realization of the regularization schemes by Newtontype iterations, present some details of the discretization by finite element methods, and outline the efficient implementation of sensitivity systems via adjoint methods. As we will demonstrate in numerical tests, the proposed nonlinear methods provide better reconstructions than standard methods based on linearized forward models and linear penalty terms. We will additionally illustrate, that the careful discretization of the methods derived on the continuous level allows to obtain reliable, mesh independent reconstruction algorithms.

  9. Advanced modelling of optical coherence tomography systems

    DEFF Research Database (Denmark)

    Andersen, Peter E.; Thrane, L.; Yura, H.T.;

    2004-01-01

    Analytical and numerical models for describing and understanding the light propagation in samples imaged by optical coherence tomography (OCT) systems are presented. An analytical model for calculating the OCT signal based on the extended Huygens–Fresnel principle valid both for the single...... and multiple scattering regimes is reviewed. An advanced Monte Carlo model for calculating the OCT signal is also reviewed, and the validity of this model is shown through a mathematical proof based on the extended Huygens–Fresnel principle. Moreover, for the first time the model is verified experimentally....... From the analytical model, an algorithm for enhancing OCT images is developed; the so-called true-reflection algorithm in which the OCT signal may be corrected for the attenuation caused by scattering. For the first time, the algorithm is demonstrated by using the Monte Carlo model as a numerical...

  10. Cubic meter volume optical coherence tomography

    Science.gov (United States)

    WANG, ZHAO; POTSAID, BENJAMIN; CHEN, LONG; DOERR, CHRIS; LEE, HSIANG-CHIEH; NIELSON, TORBEN; JAYARAMAN, VIJAYSEKHAR; CABLE, ALEX E.; SWANSON, ERIC; FUJIMOTO, JAMES G.

    2017-01-01

    Optical coherence tomography (OCT) is a powerful three-dimensional (3D) imaging modality with micrometer-scale axial resolution and up to multi-GigaVoxel/s imaging speed. However, the imaging range of high-speed OCT has been limited. Here, we report 3D OCT over cubic meter volumes using a long coherence length, 1310 nm vertical-cavity surface-emitting laser and silicon photonic integrated circuit dual-quadrature receiver technology combined with enhanced signal processing. We achieved 15 µm depth resolution for tomographic imaging at a 100 kHz axial scan rate over a 1.5 m range. We show 3D macroscopic imaging examples of a human mannequin, bicycle, machine shop gauge blocks, and a human skull/brain model. High-bandwidth, meter-range OCT demonstrates new capabilities that promise to enable a wide range of biomedical, scientific, industrial, and research applications. PMID:28239628

  11. Optical coherence tomography for diagnosing periodontal disease

    Science.gov (United States)

    Colston, Bill W., Jr.; Everett, Matthew J.; Da Silva, Luiz B.; Otis, Linda L.; Nathel, Howard

    1997-05-01

    We have, in this preliminary study, investigated the use of optical coherence tomography for diagnosis of periodontal disease. We took in vitro OCT images of the dental and periodontal tissues from a young pig and compared them to histological sections. These images distinguish tooth and soft tissue relationships that are important in diagnosing and assessing periodontal disease. We have imaged the attachment of gingiva to the tooth surface and located the cemento-enamel junction. This junction is an important reference point for defining attachment level in the diagnosis of periodontal disease. the boundary between enamel and dentin is also visible for most of the length of the anatomical crown, allowing quantitation of enamel thickness and character.

  12. Image Distortion of Optical Coherence Tomography

    Institute of Scientific and Technical Information of China (English)

    安源; 姚建铨

    2004-01-01

    A kind of image distortion in Optical Coherence Tomography (OCT) resulted from average refractive index changes between structures of bio-tissue is discussed for the first time.Analysis is given on following situations:1) Exact refraction index changes between microstructures;2)The gradient of average refractive index change between different tissue layers is parallel to the probe beam;3) The gradient of average refractive index change is vertical to the probe beam.The results show that the image distortion of situation 1) is usually negligible;in situation 2) there is a spread or shrink effect without relative location error; however,in situation 3) there is a significant image error inducing relative location displacement between different structures.Preliminary design to eliminate the distortion is presented,the method of which mainly based on the image classification and pixel array re-arrangement.

  13. EDITORIAL: Optical tomography and digital holography

    Science.gov (United States)

    Coupland, Jeremy; Lobera, Julia

    2008-07-01

    the resolution now places a limit on the size of the object that can be recorded. Some 60 years after the pioneering work of Gabor, digital imaging and associated computer technology offers a step change in capability with which to further exploit holography. Modern image sensors are now available with almost 30 million photosensitive elements, which corresponds to a staggering 100-fold increase compared to standard television images. At the same time personal computers have been optimized for imaging and graphics applications and this allows more sophisticated algorithms to be used in the reconstruction process. Although resolution still falls short of the materials used for optical holography, the ability to process data numerically generally outweighs this drawback and presents us with a host of new opportunities. Faced with the ability to record and process holograms numerically, it is natural to ask the question 'what information is present within recordings of scattered light?'. In fact this question could be posed by anyone using light, or indeed any other wave disturbance, for measurement purposes. For the case of optical holography, Wolf published his answer in 1969 [6], showing that for the case of weak scattering (small perturbations) and plane wave illumination, the amplitude and phase of each plane wave within the scattered field are proportional to those of a periodic variation in the refractive index contrast (i.e. a Bragg grating). This Fourier decomposition of the object was published almost simultaneously by Dandliker and Weiss [7], who also provided a graphical illustration of the technique. These works are the basis of optical tomography and provide us with the link between holographic data and 3D form. Digital holographic reconstruction and optical tomography was the theme of an international workshop [8] held in Loughborough in 2007, and many of the topics debated at the workshop have become the subject of the papers in this issue. In general

  14. Ultrathin lensed fiber-optic probe for optical coherence tomography.

    Science.gov (United States)

    Qiu, Y; Wang, Y; Belfield, K D; Liu, X

    2016-06-01

    We investigated and validated a novel method to develop ultrathin lensed fiber-optic (LFO) probes for optical coherence tomography (OCT) imaging. We made the LFO probe by attaching a segment of no core fiber (NCF) to the distal end of a single mode fiber (SMF) and generating a curved surface at the tip of the NCF using the electric arc of a fusion splicer. The novel fabrication approach enabled us to control the length of the NCF and the radius of the fiber lens independently. By strategically choosing these two parameters, the LFO probe could achieve a broad range of working distance and depth of focus for different OCT applications. A probe with 125μm diameter and lateral resolution up to 10μm was demonstrated. The low-cost, disposable and robust LFO probe is expected to have great potential for interstitial OCT imaging.

  15. Optical Magnetic Induction Tomography of the Heart

    Science.gov (United States)

    Marmugi, Luca; Renzoni, Ferruccio

    2016-04-01

    Atrial Fibrillation (AF) affects a significant fraction of the ageing population, causing a high level of morbidity and mortality. Despite its significance, the causes of AF are still not uniquely identified. This, combined with the lack of precise diagnostic and guiding tools, makes the clinical treatment of AF sub-optimal. We identify magnetic induction tomography as the most promising technique for the investigation of the causes of fibrillation and for its clinical practice. We therefore propose a novel optical instrument based on optical atomic magnetometers, fulfilling the requirements for diagnostic mapping of the heart’s conductivity. The feasibility of the device is here discussed in view of the final application. Thanks to the potential of atomic magnetometers for miniaturisation and extreme sensitivity at room temperature, a new generation of compact and non-invasive diagnostic instrumentation, with both bedside and intra-operative operation capability, is envisioned. Possible scenarios both in clinical practice and biomedical research are then discussed. The flexibility of the system makes it promising also for application in other fields, such as neurology and oncology.

  16. Optical coherence tomography for endodontic imaging

    Science.gov (United States)

    van Soest, G.; Shemesh, H.; Wu, M.-K.; van der Sluis, L. W. M.; Wesselink, P. R.

    2008-02-01

    In root canal therapy, complications frequently arise as a result of root fracture or imperfect cleaning of fins and invaginations. To date, there is no imaging method for nondestructive in vivo evaluation of the condition of the root canal, during or after treatment. There is a clinical need for a technique to detect defects before they give rise to complications. In this study we evaluate the ability of optical coherence tomography (OCT) to image root canal walls, and its capacity to identify complicating factors in root canal treatment. While the potential of OCT to identify caries has been explored before, endodontic imaging has not been reported. We imaged extracted lower front teeth after endodontic preparation and correlated these images to histological sections. A 3D OCT pullback scan was made with an endoscopic rotating optical fiber probe inside the root canal. All oval canals, uncleaned fins, risk zones, and one perforation that were detected by histology were also imaged by OCT. As an example of an area where OCT has clinical potential, we present a study of vertical root fracture identification with OCT.

  17. Optical coherence tomography used for internal biometrics

    Science.gov (United States)

    Chang, Shoude; Sherif, Sherif; Mao, Youxin; Flueraru, Costel

    2007-06-01

    Traditional biometric technologies used for security and person identification essentially deal with fingerprints, hand geometry and face images. However, because all these technologies use external features of human body, they can be easily fooled and tampered with by distorting, modifying or counterfeiting these features. Nowadays, internal biometrics which detects the internal ID features of an object is becoming increasingly important. Being capable of exploring under-skin structure, optical coherence tomography (OCT) system can be used as a powerful tool for internal biometrics. We have applied fiber-optic and full-field OCT systems to detect the multiple-layer 2D images and 3D profile of the fingerprints, which eventually result in a higher discrimination than the traditional 2D recognition methods. More importantly, the OCT based fingerprint recognition has the ability to easily distinguish artificial fingerprint dummies by analyzing the extracted layered surfaces. Experiments show that our OCT systems successfully detected the dummy, which was made of plasticene and was used to bypass the commercially available fingerprint scanning system with a false accept rate (FAR) of 100%.

  18. Evaluating the Use of Optical Coherence Tomography in Optic Neuritis

    Directory of Open Access Journals (Sweden)

    Fiona Costello

    2011-01-01

    Full Text Available Optic neuritis (ON is an inflammatory optic nerve injury, which is strongly associated with multiple sclerosis (MS. Axonal damage in the optic nerve manifests as retinal nerve fiber layer (RNFL deficits, which can be readily quantified with optical coherence tomography (OCT. The RNFL represents the most proximal region of the afferent visual pathway; and, as such, is a unique region of the central nervous system (CNS because it lacks myelin. Changes in retinal integrity can be correlated with reliable and quantifiable visual outcomes to provide a structural-functional paradigm of CNS injury. Because the eye provides a unique “view” into the effects of CNS inflammation, the ON “system model” may provide greater understanding about disease mechanisms, which underpin disability in MS. This review addresses the applications of OCT in study of ON patients, with specific reference to the published reports to date. The future role of OCT is discussed, both in terms of the potential gains and certain challenges associated with this evolving technology.

  19. Optical Biopsy Using Tissue Spectroscopy and Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Norman S Nishioka

    2003-01-01

    Full Text Available ‘Optical biopsy’ or ‘optical diagnostics’ is a technique whereby light energy is used to obtain information about the structure and function of tissues without disrupting them. In fluorescence spectroscopy, light energy (usually provided by a laser is used to excite tissues and the resulting fluorescence provides information about the target tissue. Its major gastrointestinal application has been in the evaluation of colonic polyps, in which it can reliably distinguish malignant from benign lesions. Optical coherence tomography (OCT has been used in the investigation of Barrett’s epithelium (and dysplasia, although a variety of other applications are feasible. For example, OCT could assist in the identification and staging of mucosal and submucosal neoplasms, the grading of inflammation in the stomach and intestine, the diagnosis of biliary tumours and the assessment of villous architecture. OCT differs from endoscopic ultrasound, a complementary modality, in that it has a much higher resolution but lesser depth of penetration. The images correlate with the histopathological appearance of tissues, and the addition of Doppler methods may enable it to evaluate the vascularity of tumours and the amount of blood flow in varices. Refinements in these new optical techniques will likely make them valuable in clinical practice, although their specific roles have yet to be determined.

  20. Coherent signal processing in optical coherence tomography

    Science.gov (United States)

    Kulkarni, Manish Dinkarrao

    1999-09-01

    Optical coherence tomography (OCT) is a novel method for non-invasive sub-surface imaging of biological tissue micro-structures. OCT achieves high spatial resolution ( ~ 15 m m in three dimensions) using a fiber-optically integrated system which is suitable for application in minimally invasive diagnostics, including endoscopy. OCT uses an optical heterodyne detection technique based on white light interferometry. Therefore extremely faint reflections ( ~ 10 fW) are routinely detected with high spatial localization. The goal of this thesis is twofold. The first is to present a theoretical model for describing image formation in OCT, and attempt to enhance the current level of understanding of this new modality. The second objective is to present signal processing methods for improving OCT image quality. We present deconvolution algorithms to obtain improved longitudinal resolution in OCT. This technique may be implemented without increasing system complexity as compared to current clinical OCT systems. Since the spectrum of the light backscattered from bio-scatterers is closely associated with ultrastructural variations in tissue, we propose a new technique for measuring spectra as a function of depth. This advance may assist OCT in differentiating various tissue types and detecting abnormalities within a tissue. In addition to depth resolved spectroscopy, Doppler processing of OCT signals can also improve OCT image contrast. We present a new technique, termed color Doppler OCT (CDOCT). It is an innovative extension of OCT for performing spatially localized optical Doppler velocimetry. Micron-resolution imaging of blood flow in sub-surface vessels in living tissue using CDOCT is demonstrated. The fundamental issues regarding the trade- off between the velocity estimation precision and image acquisition rate are presented. We also present novel algorithms for high accuracy velocity estimation. In many blood vessels velocities tend to be on the order of a few cm

  1. An All-Fiber-Optic Combined System of Noncontact Photoacoustic Tomography and Optical Coherence Tomography.

    Science.gov (United States)

    Eom, Jonghyun; Shin, Jun Geun; Park, Soongho; Rim, Sunghwan; Lee, Byeong Ha

    2016-05-20

    We propose an all-fiber-based dual-modal imaging system that combines noncontact photoacoustic tomography (PAT) and optical coherence tomography (OCT). The PAT remotely measures photoacoustic (PA) signals with a 1550-nm laser on the surface of a sample by utilizing a fiber interferometer as an ultrasound detector. The fiber-based OCT, employing a swept-source laser centered at 1310 nm, shares the sample arm of the PAT system. The fiber-optic probe for the combined system was homemade with a lensed single-mode fiber (SMF) and a large-core multimode fiber (MMF). The compact and robust common probe is capable of obtaining both the PA and the OCT signals at the same position without any physical contact. Additionally, the MMF of the probe delivers the short pulses of a Nd:YAG laser to efficiently excite the PA signals. We experimentally demonstrate the feasibility of the proposed dual-modal system with a phantom made of a fishing line and a black polyethylene terephthalate fiber in a tissue mimicking solution. The all-fiber-optic system, capable of providing complementary information about absorption and scattering, has a promising potential in minimally invasive and endoscopic imaging.

  2. Motion contrast using optical coherence tomography

    Science.gov (United States)

    Fingler, Jeffrey Paul

    Diagnosis of ophthalmic diseases like age-related macular degeneration is very important for treatment of the disease as well as the development of future treatments. Optical coherence tomography (OCT) is an optical interference technique which can measure the three-dimensional structural information of the reflecting layers within a sample. In retinal imaging, OCT is used as the primary diagnostic tool for structural abnormalities such as retinal holes and detachments. The contrast within the images of this technique is based upon reflectivity changes from different regions of the retina. This thesis demonstrates the developments of methods used to produce additional contrast to the structural OCT images based on the tiny fluctuations of motion experienced by the mobile scatterers within a sample. Motion contrast was observed for motions smaller than 50 nm in images of a variety of samples. Initial contrast method demonstrations used Brownian motion differences to separate regions of a mobile Intralipid solution from a static agarose gel, chosen in concentration to minimize reflectivity contrast. Zebrafish embryos in the range of 3-4 days post fertilization were imaged using several motion contrast methods to determine the capabilities of identifying regions of vascular flow. Vasculature identification was demonstrated in zebrafish for blood vessels of all orientations as small as 10 microns in diameter. Mouse retinal imaging utilized the same motion contrast methods to determine the contrast capabilities for motions associated with vasculature within the retina. Improved contrast imaging techniques demonstrated comparable images to fluorescein angiography, the gold standard of retinal vascular imaging. Future studies can improve the demonstrated contrast analysis techniques and apply them towards human retinal motion contrast imaging for ophthalmic diagnostic purposes.

  3. Optical Coherence Tomography in Tissue Engineering

    Science.gov (United States)

    Zhao, Youbo; Yang, Ying; Wang, Ruikang K.; Boppart, Stephen A.

    Tissue engineering holds the promise for a therapeutic solution in regenerative medicine. The primary goal of tissue engineering is the development of physiologically functional and biocompatible tissues/organs being implanted for the repair and replacement of damaged or diseased ones. Given the complexity in the developing processes of engineered tissues, which involves multi-dimensional interactions among cells of different types, three-dimensionally constructed scaffolds, and actively intervening bioreactors, a capable real-time imaging tool is critically required for expanding our knowledge about the developing process of desired tissues or organs. It has been recognized that optical coherence tomography (OCT), an emerging noninvasive imaging technique that provides high spatial resolution (up to the cellular level) and three-dimensional imaging capability, is a promising investigative tool for tissue engineering. This chapter discusses the existing and potential applications of OCT in tissue engineering. Example OCT investigations of the three major components of tissue engineering, i.e., cells, scaffolds, and bioreactors are overviewed. Imaging examples of OCT and its enabling functions and variants, e.g., Doppler OCT, polarization-sensitive OCT, optical coherence microscopy are emphasized. Remaining challenges in the application of OCT to tissue engineering are discussed, and the prospective solutions including the combination of OCT with other high-contrast and high-resolution modalities such as two-photon fluorescence microscopy are suggested as well. It is expected that OCT, along with its functional variants, will make important contributions toward revealing the complex cellular dynamics in engineered tissues as well as help us culture demanding tissue/organ implants that will advance regenerative medicine.

  4. Three-Dimensional Optical Coherence Tomography (3D OCT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Science Innovations, Inc. proposes to develop a new tool of 3D optical coherence tomography (OCT) for cellular level imaging at video frame rates and...

  5. Three-Dimensional Optical Coherence Tomography (3D OCT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Science Innovations, Inc. proposes a new tool of 3D optical coherence tomography (OCT) for cellular level imaging at video frame rates and dramatically...

  6. Anterior Eye Imaging with Optical Coherence Tomography

    Science.gov (United States)

    Huang, David; Li, Yan; Tang, Maolong

    The development of corneal and anterior segment optical coherence tomography (OCT) technology has advanced rapidly in recently years. The scan geometry and imaging wavelength are both important choices to make in designing anterior segment OCT systems. Rectangular scan geometry offers the least image distortion and is now used in most anterior OCT systems. The wavelength of OCT light source affects resolution and penetration. An optimal choice of the OCT imaging wavelength (840, 1,050, or 1,310 nm) depends on the application of interest. Newer generation Fourier-domain OCT technology can provide scan speed 100-1000 times faster than the time-domain technology. Various commercial anterior OCT systems are available on the market. A wide spectrum of diagnostic and surgical applications using anterior segment OCT had been investigated, including mapping of corneal and epithelial thicknesses, keratoconus screening, measuring corneal refractive power, corneal surgery planning and evaluation in LASIK, intracorneal ring implantation, assessment of angle closure glaucoma, anterior chamber biometry and intraocular lens implants, intraocular lens power calculation, and eye bank donor cornea screening.

  7. Polarization sensitive optical coherence tomography detection method

    Energy Technology Data Exchange (ETDEWEB)

    Everett, M J; Sathyam, U S; Colston, B W; DaSilva, L B; Fried, D; Ragadio, J N; Featherstone, J D B

    1999-05-12

    This study demonstrates the potential of polarization sensitive optical coherence tomography (PS-OCT) for non-invasive in vivo detection and characterization of early, incipient caries lesions. PS-OCT generates cross-sectional images of biological tissue while measuring the effect of the tissue on the polarization state of incident light. Clear discrimination between regions of normal and demineralized enamel is first shown in PS-OCT images of bovine enamel blocks containing well-characterized artificial lesions. High-resolution, cross-sectional images of extracted human teeth are then generated that clearly discriminate between the normal and carious regions on both the smooth and occlusal surfaces. Regions of the teeth that appeared to be demineralized in the PS-OCT images were verified using histological thin sections examined under polarized light microscopy. The PS-OCT system discriminates between normal and carious regions by measuring the polarization state of the back-scattered 1310 nm light, which is affected by the state of demineralization of the enamel. Demineralization of enamel increases the scattereing coefficient, thus depolarizing the incident light. This study shows that PS-OCT has great potential for the detection, characterization, and monitoring of incipient caries lesions.

  8. Optical Coherence Tomography Angiography in Retinal Diseases.

    Science.gov (United States)

    Chalam, K V; Sambhav, Kumar

    2016-01-01

    Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA) algorithm (a vital component of OCTA software) helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD), retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV) in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA). Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases.

  9. Anatomic Optical Coherence Tomography of Upper Airways

    Science.gov (United States)

    Chin Loy, Anthony; Jing, Joseph; Zhang, Jun; Wang, Yong; Elghobashi, Said; Chen, Zhongping; Wong, Brian J. F.

    The upper airway is a complex and intricate system responsible for respiration, phonation, and deglutition. Obstruction of the upper airways afflicts an estimated 12-18 million Americans. Pharyngeal size and shape are important factors in the pathogenesis of airway obstructions. In addition, nocturnal loss in pharyngeal muscular tone combined with high pharyngeal resistance can lead to collapse of the airway and periodic partial or complete upper airway obstruction. Anatomical optical coherence tomography (OCT) has the potential to provide high-speed three-dimensional tomographic images of the airway lumen without the use of ionizing radiation. In this chapter we describe the methods behind endoscopic OCT imaging and processing to generate full three dimensional anatomical models of the human airway which can be used in conjunction with numerical simulation methods to assess areas of airway obstruction. Combining this structural information with flow dynamic simulations, we can better estimate the site and causes of airway obstruction and better select and design surgery for patients with obstructive sleep apnea.

  10. Quantitative contrast-enhanced optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Winetraub, Yonatan; SoRelle, Elliott D. [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Biophysics Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Liba, Orly [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Zerda, Adam de la [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Biophysics Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States)

    2016-01-11

    We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects.

  11. Ultrahigh-resolution endoscopic optical coherence tomography

    Science.gov (United States)

    Chen, Yu; Herz, Paul R.; Hsiung, Pei-Lin; Aguirre, Aaron D.; Mashimo, Hiroshi; Desai, Saleem; Pedrosa, Macos; Koski, Amanda; Schmitt, Joseph M.; Fujimoto, James G.

    2005-01-01

    Early detection of gastrointestinal cancer is essential for the patient treatment and medical care. Endoscopically guided biopsy is currently the gold standard for the diagnosis of early esophageal cancer, but can suffer from high false negative rates due to sampling errors. Optical coherence tomography (OCT) is an emerging medical imaging technology which can generate high resolution, cross-sectional images of tissue in situ and in real time, without the removal of tissue specimen. Although endoscopic OCT has been used successfully to identify certain pathologies in the gastrointestinal tract, the resolution of current endoscopic OCT systems has been limited to 10 - 15 m for clinical procedures. In this study, in vivo imaging of the gastrointestinal tract is demonstrated at a three-fold higher resolution (gastro-esophageal junction and colon on animal model display tissue microstructures and architectural details at high resolution, and the features observed in the OCT images are well-matched with histology. The clinical feasibility study is conducted through delivering OCT imaging catheter using standard endoscope. OCT images of normal esophagus, Barrett's esophagus, and esophageal cancers are demonstrated with distinct features. The ability of high resolution endoscopic OCT to image tissue morphology at an unprecedented resolution in vivo would facilitate the development of OCT as a potential imaging modality for early detection of neoplastic changes.

  12. Optical coherence tomography angiography in retinal diseases

    Directory of Open Access Journals (Sweden)

    K V Chalam

    2016-01-01

    Full Text Available Optical coherence tomography angiography (OCTA is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA algorithm (a vital component of OCTA software helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD, retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA. Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases.

  13. Optical coherence tomography and Doppler optical coherence tomography in the gastrointestinal tract

    Institute of Scientific and Technical Information of China (English)

    Eugen Osiac; Adrian S(a)ftoiu; Dan Ionut Gheonea; Ion Mandrila; Radu Angelescu

    2011-01-01

    Optical coherence tomography(OCT)is a noninvasive,high-resolution,high-potential imaging method that has recently been introduced into medical investigations.A growing number of studies have used this technique in the field of gastroenterology in order to assist classical analyses.Lately,3D-imaging and Doppler capabilities have been developed in different configurations,which make this type of investigation more attractive.This paper reviews the principles and characteristics of OCT and Doppler-OCT in connection with analyses of the detection of normal and pathological structures,and with the possibility to investigate angiogenesis in the gastrointestinal tract.

  14. Adaptive optics optical coherence tomography at 1 MHz.

    Science.gov (United States)

    Kocaoglu, Omer P; Turner, Timothy L; Liu, Zhuolin; Miller, Donald T

    2014-12-01

    Image acquisition speed of optical coherence tomography (OCT) remains a fundamental barrier that limits its scientific and clinical utility. Here we demonstrate a novel multi-camera adaptive optics (AO-)OCT system for ophthalmologic use that operates at 1 million A-lines/s at a wavelength of 790 nm with 5.3 μm axial resolution in retinal tissue. Central to the spectral-domain design is a novel detection channel based on four high-speed spectrometers that receive light sequentially from a 1 × 4 optical switch assembly. Absence of moving parts enables ultra-fast (50ns) and precise switching with low insertion loss (-0.18 dB per channel). This manner of control makes use of all available light in the detection channel and avoids camera dead-time, both critical for imaging at high speeds. Additional benefit in signal-to-noise accrues from the larger numerical aperture afforded by the use of AO and yields retinal images of comparable dynamic range to that of clinical OCT. We validated system performance by a series of experiments that included imaging in both model and human eyes. We demonstrated the performance of our MHz AO-OCT system to capture detailed images of individual retinal nerve fiber bundles and cone photoreceptors. This is the fastest ophthalmic OCT system we know of in the 700 to 915 nm spectral band.

  15. Experimental Demonstration of Spectral Intensity Optical Coherence Tomography

    CERN Document Server

    Ryczkowski, Piotr; Friberg, Ari T; Genty, Goëry

    2015-01-01

    We demonstrate experimentally quantum-inspired, spectral-domain intensity optical coherence tomography. We show that the technique allows for both axial resolution improvement and dispersion cancellation compared to conventional optical coherence tomography. The method does not involve scanning and it works with classical light sources and standard photodetectors. The measurements are in excellent agreement with the theoretical predictions. We also propose an approach that enables the elimination of potential artifacts arising from multiple interfaces.

  16. Three-dimensional multifunctional optical coherence tomography for skin imaging

    Science.gov (United States)

    Li, En; Makita, Shuichi; Hong, Young-Joo; Kasaragod, Deepa; Sasaoka, Tomoko; Yamanari, Masahiro; Sugiyama, Satoshi; Yasuno, Yoshiaki

    2016-02-01

    Optical coherence tomography (OCT) visualizes cross-sectional microstructures of biological tissues. Recent developments of multifunctional OCT (MF-OCT) provides multiple optical contrasts which can reveal currently unknown tissue properties. In this contribution we demonstrate multifunctional OCT specially designed for dermatological investigation. And by utilizing it to measure four different body parts of in vivo human skin, three-dimensional scattering OCT, OCT angiography, polarization uniformity tomography, and local birefringence tomography images were obtained by a single scan. They respectively contrast the structure and morphology, vasculature, melanin content and collagen traits of the tissue.

  17. Imaging Granulomatous Lesions with Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Christina Banzhaf

    2012-01-01

    Full Text Available Aim: To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT images and compare this to previous studies of nonmelanoma skin tumors. Methods: Two patients with granulomas, tophi and granuloma annulare (GA, respectively, were photographed digitally, OCT-scanned and biopsied in the said order. Normal skin was OCT-scanned for comparison, but not biopsied. The OCT images from each lesion were compared with their histologic images as well as with OCT images with similar characteristics obtained from nonmelanoma skin tumors. Results: The OCT images of the tophi showed hyperreflective, rounded cloud-like structures in dermis, their upper part sharply delineated by a hyporeflective fringe. The deeper areas appeared blurred. The crystalline structures were delineated by a hyporeflective fringe. OCT images of GA showed two different structures in dermis: a hyporeflective rounded one, and one that was lobulated and wing-like. Conclusion: Granulomatous tissue surrounding urate deposits appeared as a clear hyporeflective fringe surrounding a light, hyperreflective area. The urate crystals appeared as hyperreflective areas, shielding the deeper part of dermis, meaning OCT could only visualize the upper part of the lesions. The lobulated, wing-like structure in GA may resemble diffuse GA or a dense lymphocytic infiltrate as seen on histology. The rounded structure in GA may represent an actual granuloma or either diffuse GA or a dense lymphocytic infiltrate as described above. This case suggests that OCT images granulomatous tissue as absorbent, hyporeflective areas, and urate crystals appear as reflective areas, obscuring the underlying tissue. In GA a new image shape looking like a wing has been found. The frequency, specificity and sensitivity of this new pattern in OCT imaging will require further studies.

  18. En-face optical coherence tomography revival

    Science.gov (United States)

    Bradu, Adrian; Kapinchev, Konstantin; Barnes, Frederick; Podoleanu, Adrian Gh.

    2016-03-01

    Quite recently, we introduced a novel Optical Coherence Tomography (OCT) method, termed as Master Slave OCT (MS-OCT), especially to deliver en-face images. MS-OCT operates like a time domain OCT, selecting signal from a selected depth only while scanning the laser beam across the sample. Time domain OCT allows real time production of an en-face image, although relatively slowly. As a major advance, the Master Slave method allows collection of signals from any number of depths, as required by the user. MS-OCT is an OCT method that does not require resampling of data and can be used to deliver en-face images from several depths simultaneously. However, as the MS-OCT method requires important computational resources, the number of multiple depth en-face images produced in real-time is limited. Here, we demonstrate that taking advantage of the parallel processing feature of the MS-OCT technology by harnessing the capabilities of graphics processing units (GPU)s, information from 384 depth positions is acquired in one raster with real time display of 40 en-face OCT images. These exhibit comparable resolution and sensitivity to the images produced using the traditional Fourier domain based method. The GPU facilitates versatile real time selection of parameters, such as the depth positions of the 40 images out of a set of 384 depth locations, as well as their axial resolution. Here, we present in parallel with the 40 en-face OCT images of a human tooth, a confocal microscopy lookalike image, together with two B-scan OCT images along rectangular directions.

  19. Self-Optical Coherence Tomography and Angiography

    Directory of Open Access Journals (Sweden)

    Ahmad M. Mansour

    2017-02-01

    Full Text Available Purpose: To present a new concept of self-optical coherence tomography (OCT and self-OCT angiography. Methods: The operator sits in the patient seat and manipulates the instrument body via the joystick with the dominant hand, while the dominant index is ready to press the capture button and while focusing on the fixation target. One senior ophthalmologist judged various OCT machines for ease of self-scan during a major ophthalmic convention. Separately, self-scans were also captured using a single OCT machine by one senior ophthalmologist and 5 junior optometrists and the scans were analyzed for both centration and image quality value (IQV, and compared to regular scans done by an operator. Results: Ten available OCT machines were tested for their ability to allow self-OCT. Machines that had one or more features of auto-alignment, auto-focus, and auto-shoot were ideal for self-OCT or self-OCT angiography. Self-scans done by the ophthalmologist (total 27 scans of right eye, mean IQV = 32.6, and 24 left eyes, mean IQV = 37.3, done over 9 months and 5 optometrists (total 24 scans, mean 34.8 done in one session were comparable to scans (total 11, mean IQV = 38.1 done by an operator for image quality. Decentration was very common in self-scans of the macula (37% right eye and 46% left eye versus 0% for scans of the right eye done by an operator. Conclusions: Self-OCT scans of the macular region can be done with good image quality but are often decentered. Advantages include privacy, potential use by ophthalmic health professionals, airspace station officers, and possible future home self-imaging of macula.

  20. Optical Coherence Tomography for Brain Imaging

    Science.gov (United States)

    Liu, Gangjun; Chen, Zhongping

    Recently, there has been growing interest in using OCT for brain imaging. A feasibility study of OCT for guiding deep brain probes has found that OCT can differentiate the white matter and gray matter because the white matter tends to have a higher peak reflectivity and steeper attenuation rate compared to gray matter. In vivo 3D visualization of the layered organization of a rat olfactory bulb with OCT has been demonstrated. OCT has been used for single myelin fiber imaging in living rodents without labeling. The refractive index in the rat somatosensory cortex has also been measured with OCT. In addition, functional extension of OCT, such as Doppler-OCT (D-OCT), polarization sensitive-OCT (PS-OCT), and phase-resolved-OCT (PR-OCT), can image and quantify physiological parameters in addition to the morphological structure image. Based on the scattering changes during neural activity, OCT has been used to measure the functional activation in neuronal tissues. PS-OCT, which combines polarization sensitive detection with OCT to determine tissue birefringence, has been used for the localization of nerve fiber bundles and the mapping of micrometer-scale fiber pathways in the brain. D-OCT, also named optical Doppler tomography (ODT), combines the Doppler principle with OCT to obtain high resolution tomographic images of moving constituents in highly scattering biological tissues. D-OCT has been successfully used to image cortical blood flow and map the blood vessel network for brain research. In this chapter, the principle and technology of OCT and D-OCT are reviewed and examples of potential applications are described.

  1. Carious growth monitoring with optical coherence tomography

    Science.gov (United States)

    Freitas, A. Z.; Zezell, D. M.; Mayer, M. P. A.; Ribeiro, A. C.; Gomes, A. S. L.; Vieira, N. D., Jr.

    2006-02-01

    Optical Coherence Tomography was used to monitor subsurface caries evolution process in vitro. Human tooth was used and bacteria were employed to induce caries lesions. Twenty-five human third molars, were used in this study. The teeth were cut longitudinally at mesio-distal direction; the surfaces were coated with nail varnish except for two squared windows (2x4 mm); at the cement-enamel junction. Artificial lesions were induced by a S. Mutans microbiological culture. The samples (N = 50) were divided into groups according to the demineralization time: 3, 5, 7, 9 and 11 days. The culture medium, was changed each 48 hours. After the demineralization process the samples were rinsed with double-deionized water and stored in a humid environment. The OCT system was implemented with average power of 96 μW in the sample arm, providing a 23 μm of axial resolution. The images were produced with lateral scans step of 10 μm. The detection system was composed by a detector, a demodulator and a computer. With the images generated by OCT it was possible to determine the lesion depth as function of sample exposition time to microbiological culture. We observed that the depth of the lesion in the root dentine increased from 70 μm to 230 μm, depending of exposure time, and follows the bacterial population growth law. This OCT system accurately depicts hard dental tissue and it was able to detect early caries in its structure, providing a powerful contactless high resolution image of lesions.

  2. Applications of Doppler optical coherence tomography

    Science.gov (United States)

    Xu, Zhiqiang

    A major development in biomedical imaging in the last decade has been optical coherence tomography (OCT). This technique enables microscale resolution, depth resolved imaging of the detailed morphology of transparent and nontransparent biological tissue in a noncontact and quasi-noninvasive way. In the first part of this dissertation, we will describe the development and the performance of our home-made OCT systems working with different wavelength regions based on free-space and optical fiber Michelson interferometers. The second part will focus on Doppler OCT (DOCT), an important extension of OCT, which enables the simultaneous evaluation of the structural information and of the fluid flow distribution at a localized position beneath the sample surface. Much effort has been spent during the past few years in our laboratory aimed at providing more accurate velocity measurements with an extended dynamic range. We also applied our technique in different research areas such as microfluidics and hemodynamics. Investigations on the optical properties of the biological tissues (such as absorption and scattering) corresponding to different center wavelengths, have been performed in our laboratory. We used a 10 femtosecond Ti:sapphire laser centered at about 810 nm associated with a free-space Michelson interferometer. The infrared sources were centered at about 1310 and 1560 nm with all-fiber interferometers. Comparative studies using three different sources for several in vitro biological tissues based on a graphical method illustrated how the optical properties affect the quality of the OCT images in terms of the penetration depth and backscattering intensity. We have shown the advantage of working with 810-nm emission wavelength for good backscattering amplitude and contrast, while sources emitting at 1570 nm give good penetration depth. The 1330-nm sources provide a good compromise between the two. Therefore, the choice of the source will ultimately determine the

  3. Spectral-domain optical coherence tomography on a silicon chip

    NARCIS (Netherlands)

    Akca, Bakiye Imran

    2012-01-01

    Optical coherence tomography (OCT) is a non-invasive optical technique for high-resolution cross-sectional imaging of specimens, with many applications in clinical medicine and industry (e.g. materials testing, quality assurance, and process control). Current state-of-the-art OCT systems operate in

  4. OPTICAL COHERENCE TOMOGRAPHY IN JUVENILE NEURONAL CEROID LIPOFUSCINOSIS

    DEFF Research Database (Denmark)

    Hansen, Michael S.; Hove, Marianne N; Jensen, Hanne;

    2016-01-01

    PURPOSE: To report optical coherence tomography findings obtained in two patients with juvenile neuronal ceroid lipofuscinosis. METHODS: Two case reports. RESULTS: Two 7-year-old girls presented with decreased visual acuity, clumsiness, night blindness, and behavioral problems. Optical coherence...... tomography showed an overall reduction in thickness of the central retina, as well as the outer and the inner retinal layers. The degenerative retinal changes were the same, despite different mutations in the CLN3 gene. CONCLUSION: In these rare cases of juvenile neuronal ceroid lipofuscinosis, optical...

  5. Accuracy of optical navigation systems for automatic head surgery: optical tracking versus optical coherence tomography

    Science.gov (United States)

    Díaz Díaz, Jesús; Riva, Mauro H.; Majdani, Omid; Ortmaier, Tobias

    2014-03-01

    The choice of a navigation system highly depends on the medical intervention and its accuracy demands. The most commonly used systems for image guided surgery (IGS) are based on optical and magnetic tracking systems. This paper compares two optical systems in terms of accuracy: state of the art triangulation-based optical tracking (OT) and optical coherence tomography (OCT). We use an experimental setup with a combined OCT and cutting laser, and an external OT. We simulate a robotic assisted surgical intervention, including planning, navigation, and processing, and compare the accuracies reached at a specific target with each navigation system.

  6. Spatial Fourier-decomposition optical fluorescen tomography-theoretical investigation

    Institute of Scientific and Technical Information of China (English)

    Cheng Liu; Dug Young Kim; Jianqiang Zhu

    2008-01-01

    A new three-dimensional (3D) optical fluorescent tomographic imaging scheme is proposed with structured illumination and spatial Fourierdomain decomposition methods for the first time. In this spatial Fourier-decomposition optical fluorescence tomography (SF-OFT), the intensity of focused excitation light from an objective lens is modulated to be a cosine function along the optical axis of the system. For a given position in a two-dimensional (2D) raster scanning process, the spatial frequency of the cosine function along the optical axis sweeps in a proper range while a series of fluorescence intensity are detected accordingly. By making an inverse discrete cosine transformation of these recorded intensity profiles, the distribution of fluorescent markers along the optical axis of a focused laser beam is obtained. A 3D optical fluorescent tomography can be achieved with this proposed SF-OFT technique with a simple 2D raster scanning process.

  7. The Development, Commercialization, and Impact of Optical Coherence Tomography.

    Science.gov (United States)

    Fujimoto, James; Swanson, Eric

    2016-07-01

    This review was written for the special issue of IOVS to describe the history of optical coherence tomography (OCT) and its evolution from a nonscientific, historic perspective. Optical coherence tomography has become a standard of care in ophthalmology, providing real-time information on structure and function - diagnosing disease, evaluating progression, and assessing response to therapy, as well as helping to understand disease pathogenesis and create new therapies. Optical coherence tomography also has applications in multiple clinical specialties, fundamental research, and manufacturing. We review the early history of OCT describing how research and development evolves and the important role of multidisciplinary collaboration and expertise. Optical coherence tomography had its origin in femtosecond optics, but used optical communications technologies and required advanced engineering for early OCT prototypes, clinical feasibility studies, entrepreneurship, and corporate development in order to achieve clinical acceptance and clinical impact. Critical advances were made by early career researchers, clinician scientists, engineering experts, and business leaders, which enabled OCT to have a worldwide impact on health care. We introduce the concept of an "ecosystem" consisting of research, government funding, collaboration and competition, clinical studies, innovation, entrepreneurship and industry, and impact - all of which must work synergistically. The process that we recount is long and challenging, but it is our hope that it might inspire early career professionals in science, engineering, and medicine, and that the clinical and research community will find this review of interest.

  8. Mapping distributed brain function and networks with diffuse optical tomography

    Science.gov (United States)

    Eggebrecht, Adam T.; Ferradal, Silvina L.; Robichaux-Viehoever, Amy; Hassanpour, Mahlega S.; Dehghani, Hamid; Snyder, Abraham Z.; Hershey, Tamara; Culver, Joseph P.

    2014-06-01

    Mapping of human brain function has revolutionized systems neuroscience. However, traditional functional neuroimaging by positron emission tomography or functional magnetic resonance imaging cannot be used when applications require portability, or are contraindicated because of ionizing radiation (positron emission tomography) or implanted metal (functional magnetic resonance imaging). Optical neuroimaging offers a non-invasive alternative that is radiation free and compatible with implanted metal and electronic devices (for example, pacemakers). However, optical imaging technology has heretofore lacked the combination of spatial resolution and wide field of view sufficient to map distributed brain functions. Here, we present a high-density diffuse optical tomography imaging array that can map higher-order, distributed brain function. The system was tested by imaging four hierarchical language tasks and multiple resting-state networks including the dorsal attention and default mode networks. Finally, we imaged brain function in patients with Parkinson's disease and implanted deep brain stimulators that preclude functional magnetic resonance imaging.

  9. Optical coherence tomography of the prostate nerves

    Science.gov (United States)

    Chitchian, Shahab

    Preservation of the cavernous nerves during prostate cancer surgery is critical in preserving a man's ability to have spontaneous erections following surgery. These microscopic nerves course along the surface of the prostate within a few millimeters of the prostate capsule, and they vary in size and location from one patient to another, making preservation of the nerves difficult during dissection and removal of a cancerous prostate gland. These observations may explain in part the wide variability in reported sexual potency rates (9--86%) following prostate cancer surgery. Any technology capable of providing improved identification, imaging, and visualization of the cavernous nerves during prostate cancer surgery would be of great assistance in improving sexual function after surgery, and result in direct patient benefit. Optical coherence tomography (OCT) is a noninvasive optical imaging technique capable of performing high-resolution cross-sectional in vivo and in situ imaging of microstructures in biological tissues. OCT imaging of the cavernous nerves in the rat and human prostate has recently been demonstrated. However, improvements in the OCT system and the quality of the images for identification of the cavernous nerves is necessary before clinical use. The following chapters describe complementary approaches to improving identification and imaging of the cavernous nerves during OCT of the prostate gland. After the introduction to OCT imaging of the prostate gland, the optimal wavelength for deep imaging of the prostate is studied in Chapter 2. An oblique-incidence single point measurement technique using a normal-detector scanning system was implemented to determine the absorption and reduced scattering coefficients, mua and m's , of fresh canine prostate tissue, ex vivo, from the diffuse reflectance profile of near-IR light as a function of source-detector distance. The effective attenuation coefficient, mueff, and the Optical Penetration Depth (OPD) were

  10. Optical atomic magnetometry for magnetic induction tomography of the heart

    CERN Document Server

    Deans, Cameron; Hussain, Sarah; Renzoni, Ferruccio

    2016-01-01

    We report on the use of radio-frequency optical atomic magnetometers for magnetic induction tomography measurements. We demonstrate the imaging of dummy targets of varying conductivities placed in the proximity of the sensor, in an unshielded environment at room-temperature and without background subtraction. The images produced by the system accurately reproduce the characteristics of the actual objects. Furthermore, we perform finite element simulations in order to assess the potential for measuring low-conductivity biological tissues with our system. Our results demonstrate the feasibility of an instrument based on optical atomic magnetometers for magnetic induction tomography imaging of biological samples, in particular for mapping anomalous conductivity in the heart.

  11. Optical Doppler tomography based on a field programmable gate array

    DEFF Research Database (Denmark)

    Larsen, Henning Engelbrecht; Nilsson, Ronnie Thorup; Thrane, Lars

    2008-01-01

    We report the design of and results obtained by using a field programmable gate array (FPGA) to digitally process optical Doppler tomography signals. The processor fits into the analog signal path in an existing optical coherence tomography setup. We demonstrate both Doppler frequency and envelope...... extraction using the Hilbert transform, all in a single FPGA. An FPGA implementation has certain advantages over general purpose digital signal processor (DSP) due to the fact that the processing elements operate in parallel as opposed to the DSP. which is primarily a sequential processor....

  12. High-resolution second harmonic optical coherence tomography

    Science.gov (United States)

    Jiang, Yi; Tomov, Ivan V.; Wang, Yimin; Chen, Zhongping

    2005-04-01

    A high-resolution Second Harmonic Optical Coherence Tomography (SH-OCT) system is demonstrated using a spectrum broadened femtosecond Ti:sapphire laser. An axial resolution of 4.2 μm at the second harmonic wave center wavelength of 400 nm has been achieved. Because the SH-OCT system uses the second harmonic generation signals that strongly depend on the orientation, polarization and local symmetry properties of chiral molecules, this technique provides unique contrast enhancement to conventional optical coherence tomography. The system is applied to image biological tissues like the rat-tail tendon. Images of highly organized collagen fibrils in the rat-tail tendon have been demonstrated.

  13. [Applications of optical coherence tomography (OCT) in neuro-ophthalmology].

    Science.gov (United States)

    Kernstock, C; Friebe, K; Tonagel, F

    2013-11-01

    Optical coherence tomography (OCT) has revolutionised ophthalmology. Due to modern instruments with extremely high resolution there are more and more applications also in neuro-ophthalmological disorders. This review gives an overview on typical changes in OCT for the following diseases: autosomal dominant optic atrophy, Leber hereditary optic neuropathy, toxic, traumatic and compressive optic neuropathy, optic nerve drusen, anterior ischaemic optic neuropathy, optic disc pit, papilledema, optic neuritis (isolated or associated with multiple sclerosis or neuromyelitis optica), neurodegenerative diseases and hereditary retinal diseases. A diagnosis exclusively based on an OCT examination is not always possible, but in several diseases there are pathognomonic changes that directly lead to the correct diagnosis. Particularly with the often complex settings in neuro-ophtalmology the OCT should be seen as a supplementary modality and not as a replacement for other techniques.

  14. Spectral domain optical coherence tomography and microperimetry in foveal hypoplasia

    Directory of Open Access Journals (Sweden)

    Swakshyar Saumya Pal

    2011-01-01

    Full Text Available A case of foveal hypoplasia associated with ocular albinism with anatomic and functional changes by various techniques using spectral domain optical coherence tomography (SD-OCT, microperimeter and confocal scanning laser ophthalmoscope is described. This case highlights the importance of microperimeter in detecting the functional abnormalities of vision and SD-OCT in identifying the retinal laminar abnormalities in foveal hypoplasia.

  15. TOPICAL REVIEW: Optical tomography: forward and inverse problems

    Science.gov (United States)

    Arridge, Simon R.; Schotland, John C.

    2009-12-01

    This is a review of recent mathematical and computational advances in optical tomography. We discuss the physical foundations of forward models for light propagation on microscopic, mesoscopic and macroscopic scales. We also consider direct and numerical approaches to the inverse problems that arise at each of these scales. Finally, we outline future directions and open problems in the field.

  16. Visible-Light Tomography Using an Optical Imaging-System

    NARCIS (Netherlands)

    Ingesson, L. C.; Koning, J. J.; Donne, A. J. H.; D.C. Schram,

    1992-01-01

    A system for tomography in the wavelength range 200-1 100 nm has been designed for the Rijnhuizen Tokamak Project (RTP). The plasma is viewed from five directions in one poloidal plane with a total of 80 detectors. An optical imaging system consisting of two spherical mirrors for each viewing direct

  17. Optical coherent tomography in diagnoses of peripheral retinal degenarations

    Directory of Open Access Journals (Sweden)

    O. G. Pozdeyeva

    2013-01-01

    Full Text Available Purpose: Studying the capabilities of optical coherence tomography (RTVue-100, OPTOVUE, USA in evaluation of peripheral retinal degenerations, vitreoretinal adhesions, adjacent vitreous body as well as measurement of morphometric data.Methods: The study included 189 patients (239 eyes with peripheral retinal degeneration. 77 men and 112 women aged 18 to 84 underwent an ophthalmologic examination since November 2012 until October 2013. The peripheral retina was visualized with the help of optical coherence tomography («RTVue-100,» USA. The fundography was carried out using a Nikon NF505‑AF (Japan fundus camera. All patients were examined with a Goldmann lens.Results: Optical coherence tomography was used to evaluate different kinds of peripheral retinal degenerations, such as lattice and snail track degeneration, isolated retinal tears, cystoid retinal degeneration, pathological hyperpigmentation, retinoschisis and cobblestone degeneration. The following morphometric data were studied: dimensions of the lesion (average length, retinal thickness along the edge of the lesion, retinal thickness at the base of the lesion and the vitreoretinal interface.Conclusion: Optical coherence tomography is a promising in vivo visualization method which is useful in evaluation of peripheral retinal degenerations, vitreoretinal adhesions and tractions. It also provides a comprehensive protocolling system and monitoring. It will enable ophthalmologists to better define laser and surgical treatment indications and evaluate therapy effectiveness.

  18. Polarization-Sensitive Quantum Optical Coherence Tomography: Experiment

    CERN Document Server

    Booth, Mark C; Teich, Malvin Carl

    2010-01-01

    Polarization-sensitive quantum optical coherence tomography (PS-QOCT) makes use of a Type-II twin-photon light source for carrying out optical sectioning with polarization sensitivity. A BBO nonlinear optical crystal pumped by a Ti:sapphire psec-pulsed laser is used to confirm the theoretical underpinnings of this imaging paradigm. PS-QOCT offers even-order dispersion cancellation with simultaneous access to the group-velocity dispersion characteristics of the interstitial medium between the reflecting surfaces of the sample.

  19. Optical Coherence Tomography to Assess Neurodegeneration in Multiple Sclerosis.

    Science.gov (United States)

    Petzold, Axel

    2016-01-01

    Retinal spectral domain optical coherence tomography (OCT) has emerged as a clinical and research tool in multiple sclerosis (MS) and optic neuritis (ON). This chapter summarizes a short OCT protocol as included in international consensus guidelines. The protocol was written for hands-on style such that both clinicians and OCT technicians can make use of it. The protocol is suitable for imaging of the optic nerve head and macular regions as a baseline for follow-up investigations, individual layer segmentation, and diagnostic assessment.

  20. Application of optical longitudinal tomography for dental introscopy

    Science.gov (United States)

    Levin, Gennady G.; Burgansky, Alexander A.; Levandovski, Alexei G.

    1997-08-01

    A new method of dental introscopy in-vitro is suggested by the authors. This method implies the usage of longitudinal tomography techniques and is characterized by non-invasive and non-harmful diagnostics features, as well as interactive regime of image reconstruction which lets an operator (doctor) to control the diagnostics process in real time. He-Ne laser emission is used for obtaining of the projections. By the means of longitudinal tomography, images of different sections of an object (tooth) can be reconstructed. An experiment was held by the authors in which 100 projections of a tooth (premolar) were obtained and images of 10 different sections were reconstructed. These images were later compared to real sections of the tooth. This experiment proved that optical longitudinal tomography can be successfully used for dental introscopy. Authors claim that optical tomographic methods can be used for diagnostics of other biological objects as well. Such objects are characterized by spatial geometrical anisotropy (tubular bones, phalanxes of fingers, penis, etc.). It is especially promising to use this method for children's dentistry. the authors discuss some features of the data acquisition system for optical longitudinal tomography. Reconstruction algorithms are described. The results of experimental reconstruction are presented and advantages of this diagnostics method are discussed.

  1. Early results of the posterior saggital anorectoplasty in the treatment of anorectal malformations in Nigerian children

    Directory of Open Access Journals (Sweden)

    Sowande O

    2006-01-01

    Full Text Available CONTEXT: The ultimate goal of reconstruction in anorectal malformations (ARM in children, is to create a functional and anatomically aesthetic neoanus. AIMS: To document our experience with the technique of PSARP in ARM and the immediate anatomical and functional outcome SETTINGS AND DESIGN: A retrospective study 39 patients with high and intermediate ARM, managed by the posterior saggital approach, at the Obafemi Awolowo University Teaching Hospital in Ile Ife, Nigeria MATERIALS AND METHODS: Patient′s bio-data were collected, as well as, the presentation, investigations, associated malformations, complications, average bowel opening per day and follow up. RESULTS: There were 17 males and 22 females (male: female ratio 1: 1.3. Twenty-three patients (59% and 15 patients (38.5%, had intermediate and high malformations respectively, while 1(2.5% had cloaca malformation. The mean age at presentation was 13.9±30.1 month (range 2 day to 15 years, while the mean age at PSARP was 21.6±29.9 months (range 2.5 days to 15 years. 3(7.6% patients required laparotomy to mobilize the rectal pouch from the abdomen. Mucosal prolapse was the most common significant postoperative problem, occurring in 4(10.3% patients. The average bowel motion was 3 times daily (range 1 to 8 times per day. CONCLUSIONS: The PSARP is a useful procedure for the correction of ARM, in children in developing countries, even in the absence of muscle stimulators. The immediate anatomical outcome is satisfactory, but functional results are difficult to access because of poor follow up.

  2. Imaging cutaneous T-Cell lymphoma with optical coherence tomography

    DEFF Research Database (Denmark)

    Ring, H.C.; Hansen Stamp, I.M.; Jemec, G.B.E.

    2012-01-01

    Aim: To investigate the presentation of a patch-stage cutaneous T-cell lymphoma (CTCL) using optical coherence tomography (OCT). Methods: A patient with a patch caused by CTCL was photographed digitally, OCT-scanned and biopsied. A normal skin area adjacent to the patch was OCT-scanned for compar......Aim: To investigate the presentation of a patch-stage cutaneous T-cell lymphoma (CTCL) using optical coherence tomography (OCT). Methods: A patient with a patch caused by CTCL was photographed digitally, OCT-scanned and biopsied. A normal skin area adjacent to the patch was OCT.......13 mm. A good immediate correlation was found between histology and OCT imaging of the sample. Conclusion: The aetiology of the elongated structures is thought to be lymphomatous infiltrates. Similar findings have been described in ocular lymphoma and may therefore be an important characteristic...

  3. Analysis of multiple scattering effects in optical Doppler tomography

    DEFF Research Database (Denmark)

    Yura, H.T.; Thrane, L.; Andersen, Peter E.

    2005-01-01

    Optical Doppler tomography (ODT) combines Doppler velocimetry and optical coherence tomography (OCT) to obtain high-resolution cross-sectional imaging of particle flow velocity in scattering media such as the human retina and skin. Here, we present the results of a theoretical analysis of ODT where...... multiple scattering effects are included. The purpose of this analysis is to determine how multiple scattering affects the estimation of the depth-resolved localized flow velocity. Depth-resolved velocity estimates are obtained directly from the corresponding mean or standard deviation of the observed...... Doppler frequency spectrum. Thus, in the present analysis, the dependence of the mean and standard deviation of the Doppler shift on the scattering properties of the flowing medium are obtained. Taking the multiple scattering effects into account, we are able to explain previous measurements of depth...

  4. Digital optical tomography system for dynamic breast imaging.

    Science.gov (United States)

    Flexman, Molly L; Khalil, Michael A; Al Abdi, Rabah; Kim, Hyun K; Fong, Christopher J; Desperito, Elise; Hershman, Dawn L; Barbour, Randall L; Hielscher, Andreas H

    2011-07-01

    Diffuse optical tomography has shown promising results as a tool for breast cancer screening and monitoring response to chemotherapy. Dynamic imaging of the transient response of the breast to an external stimulus, such as pressure or a respiratory maneuver, can provide additional information that can be used to detect tumors. We present a new digital continuous-wave optical tomography system designed to simultaneously image both breasts at fast frame rates and with a large number of sources and detectors. The system uses a master-slave digital signal processor-based detection architecture to achieve a dynamic range of 160 dB and a frame rate of 1.7 Hz with 32 sources, 64 detectors, and 4 wavelengths per breast. Included is a preliminary study of one healthy patient and two breast cancer patients showing the ability to identify an invasive carcinoma based on the hemodynamic response to a breath hold.

  5. Optical coherence tomography-based micro-particle image velocimetry.

    Science.gov (United States)

    Mujat, Mircea; Ferguson, R Daniel; Iftimia, Nicusor; Hammer, Daniel X; Nedyalkov, Ivaylo; Wosnik, Martin; Legner, Hartmut

    2013-11-15

    We present a new application of optical coherence tomography (OCT), widely used in biomedical imaging, to flow analysis in near-wall hydrodynamics for marine research. This unique capability, called OCT micro-particle image velocimetry, provides a high-resolution view of microscopic flow phenomena and measurement of flow statistics within the first millimeter of a boundary layer. The technique is demonstrated in a small flow cuvette and in a water tunnel.

  6. Parallel optical coherence tomography using a CCD camera

    Institute of Scientific and Technical Information of China (English)

    Junle Qu(屈军乐); Ravi S.Jonnal; Donald T. Miller

    2004-01-01

    Parallel optical coherence tomography is demonstrated using a 12-bit scientific-grade charge-coupled device array.A superluminescent diode in combination with a free-space Michelson interferometer was employed to achieve 10-μm axial resolution and 1.1-μm transverse resolution on a 902×575 μm2 field of view.We imaged a test mirror and bovine retinal tissue using a four-step phase shift method.

  7. Submicron Resolution Spectral-Domain Optical Coherence Tomography

    KAUST Repository

    Alarousu, Erkki

    2013-11-14

    Apparatuses and systems for submicron resolution spectral-domain optical coherence tomography (OCT) are disclosed. The system may use white light sources having wavelengths within 400-1000 nanometers, and achieve resolution below 1 .mu.m. The apparatus is aggregated into a unitary piece, and a user can connect the apparatus to a user provided controller and/or light source. The light source may be a supercontinuum source.

  8. The APOSTEL recommendations for reporting quantitative optical coherence tomography studies

    DEFF Research Database (Denmark)

    Cruz-Herranz, Andrés; Balk, Lisanne J; Oberwahrenbrock, Timm

    2016-01-01

    OBJECTIVE: To develop consensus recommendations for reporting of quantitative optical coherence tomography (OCT) study results. METHODS: A panel of experienced OCT researchers (including 11 neurologists, 2 ophthalmologists, and 2 neuroscientists) discussed requirements for performing and reporting...... relevant when reporting quantitative OCT studies. The areas covered are study protocol, acquisition device, acquisition settings, scanning protocol, funduscopic imaging, postacquisition data selection, postacquisition data analysis, recommended nomenclature, and statistical analysis. CONCLUSIONS...

  9. Multifocal cysticercosis with optical coherence tomography findings in a child

    Directory of Open Access Journals (Sweden)

    Manisha Agarwal

    2012-01-01

    Full Text Available We herein report a case with multifocal cysticercosis - sub-conjunctival cysticercus cyst, sub-retinal cysticercosis, and neurocysticercosis in a child. The optical coherence tomography (OCT findings of the sub-retinal cysticercus cyst are reported. He was treated with anti-helminthic drugs and oral prednisolone followed by surgical removal of the sub-retinal cyst. He subsequently underwent silicone oil removal with lens aspiration and intraocular lens implantation maintaining stable vision

  10. Clinical optical coherence tomography combined with multiphoton tomography of patients with skin diseases.

    Science.gov (United States)

    König, Karsten; Speicher, Marco; Bückle, Rainer; Reckfort, Julia; McKenzie, Gordon; Welzel, Julia; Koehler, Martin J; Elsner, Peter; Kaatz, Martin

    2009-07-01

    We report on the first clinical study based on optical coherence tomography (OCT) in combination with multiphoton tomography (MPT) and dermoscopy. 47 patients with a variety of skin diseases and disorders such as skin cancer, psoriasis, hemangioma, connective tissue diseases, pigmented lesions, and autoimmune bullous skin diseases have been investigated with (i) state-of-the-art OCT systems for dermatology including multibeam swept source OCT, (ii) the femtosecond laser multiphoton tomograph, and (iii) dermoscopes. Dermoscopy provides two-dimensional color images of the skin surface. OCT images reflect modifications of the intratissue refractive index whereas MPT is based on nonlinear excitation of endogenous fluorophores and second harmonic generation. A stack of cross-sectional OCT "wide field" images with a typical field of view of 5 x 2 mm(2) gave fast information on the depth and the volume of the lesion. Multiphoton tomography provided 0.36 x 0.36 mm(2) horizontal/diagonal optical sections within seconds of a particular region of interest with superior submicron resolution down to a tissue depth of 200 mum. The combination of OCT and MPT provides a unique powerful optical imaging modality for early detection of skin cancer and other skin diseases as well as for the evaluation of the efficiency of treatments.

  11. Breast cancer detection using phase contrast diffuse optical tomography

    Science.gov (United States)

    Liang, Xiaoping; Zhang, Qizhi; Li, Changqing; Grobmyer, Stephen R.; Fajardo, Laurie L.; Jiang, Huabei

    2007-02-01

    In this report, a phase-contrast diffuse optical tomography system, which can measure the refractive indices of human breast masses in vivo, is described. To investigate the utility of phase-contrast diffuse optical tomography (PCDOT) for differentiation of malignant and benign breast masses in humans, and to compare PCDOT with conventional diffuse optical tomography (DOT) for analysis of breast masses in humans. 35 breast masses were imaged in 33 patients (mean age = 51 years; range 22-80 years) using PCDOT. Images characterizing the tissue refractive index, absorption and scattering of breast masses were obtained with a finite element-based reconstruction algorithm. The accuracies of absorption and scattering images were compared with images of refractive index in light of the pathology results. Absorption and scattering images were unable to accurately discriminate benign from malignant lesions. Malignant lesions tended to have decreased refractive index allowing them to discriminate from benign lesions in most cases. The sensitivity, specificity, false positive value, and overall accuracy for refractive index were 81.8%, 70.8%, 29.2%, and 74.3%, respectively. Overall we show that benign and malignant breast masses in humans demonstrate different refractive index and differences in refractive index properties can be used to discriminate benign from malignant masses in patients with high accuracy. This opens up a new avenue for improved breast cancer detection using NIR diffusing light.

  12. Functional Doppler optical coherence tomography for cortical blood flow imaging

    Science.gov (United States)

    Yu, Lingfeng; Liu, Gangjun; Nguyen, Elaine; Choi, Bernard; Chen, Zhongping

    2010-02-01

    Optical methods have been widely used in basic neuroscience research to study the cerebral blood flow dynamics in order to overcome the low spatial resolution associated with magnetic resonance imaging and positron emission tomography. Although laser Doppler imaging and laser speckle imaging can map out en face cortical hemodynamics and columns, depth resolution is not available. Two-photon microscopy has been used for mapping cortical activity. However, flow measurement requires fluorescent dye injection, which can be problematic. The noninvasive and high resolution tomographic capabilities of optical coherence tomography make it a promising technique for mapping depth resolved cortical blood flow. Here, we present a functional Doppler optical coherence tomography (OCT) imaging modality for quantitative evaluation of cortical blood flow in a mouse model. Fast, repeated, Doppler OCT scans across a vessel of interest were performed to record flow dynamic information with a high temporal resolution of the cardiac cycles. Spectral Doppler analysis of continuous Doppler images demonstrates how the velocity components and longitudinally projected flow-volume-rate change over time, thereby providing complementary temporal flow information to the spatially distributed flow information of Doppler OCT. The proposed functional Doppler OCT imaging modality can be used to diagnose vessel stenosis/blockage or monitor blood flow changes due to pharmacological agents/neuronal activities. Non-invasive in-vivo mice experiments were performed to verify the capabilities of function Doppler OCT.

  13. Algorithm for localized adaptive diffuse optical tomography and its application in bioluminescence tomography

    Science.gov (United States)

    Naser, Mohamed A.; Patterson, Michael S.; Wong, John W.

    2014-04-01

    A reconstruction algorithm for diffuse optical tomography based on diffusion theory and finite element method is described. The algorithm reconstructs the optical properties in a permissible domain or region-of-interest to reduce the number of unknowns. The algorithm can be used to reconstruct optical properties for a segmented object (where a CT-scan or MRI is available) or a non-segmented object. For the latter, an adaptive segmentation algorithm merges contiguous regions with similar optical properties thereby reducing the number of unknowns. In calculating the Jacobian matrix the algorithm uses an efficient direct method so the required time is comparable to that needed for a single forward calculation. The reconstructed optical properties using segmented, non-segmented, and adaptively segmented 3D mouse anatomy (MOBY) are used to perform bioluminescence tomography (BLT) for two simulated internal sources. The BLT results suggest that the accuracy of reconstruction of total source power obtained without the segmentation provided by an auxiliary imaging method such as x-ray CT is comparable to that obtained when using perfect segmentation.

  14. Modeling light–tissue interaction in optical coherence tomography systems

    DEFF Research Database (Denmark)

    Andersen, Peter E.; Jørgensen, Thomas Martini; Thrane, Lars

    2015-01-01

    Optical coherence tomography (OCT) performs high-resolution, cross-sectional tomographic imaging of the internal tissue microstructure by measuring backscattered or backreflected light. The scope of this chapter is to present analytical and numerical models that are able to describe light......-tissue interactions and its influence on the performance of OCT systems including multiple scattering effects in heterogeneous media. In general, these models, analytical as well as numerical, may serve as important tools for improving interpretation of OCT images and also serve as prerequisites for extraction...... of tissue optical scattering parameters....

  15. The diagnosis of nasopharyngeal carcinoma by optical coherence tomography (OCT)

    Science.gov (United States)

    Li, J. H.; Du, Y.

    2016-06-01

    We have attempted to explore the intrinsic differences in the optical properties of the nasopharyngeal carcinoma (NPC) and normal tissue by optical coherence tomography (OCT). OCT imaging of normal tissue provided three layers of epithelium, lamina propria, and the brighter interface of basement membrane; while carcinomas disrupted the layered construction embedded in signal-poor images. The morphologies were consistent with histological findings. Sensitivity and specificity were 90% and 100%, respectively. This pilot study demonstrates that NPC could be diagnosed by visualization, which implies that OCT might be potentially used to differentiate normal from NPC tissue in the early stage as an invasive biopsy.

  16. Optical Coherence Tomography in Pulmonary Medicine

    Science.gov (United States)

    Murgu, Septimiu Dan; Brenner, Matthew; Chen, Zhongping; Suter, Melissa J.

    Advances in pulmonary diagnostics and therapeutics offer a major potential for optical imaging applications both in clinical practice and research settings. Complexities of pulmonary structures and function have restricted widespread OCT investigations and clinical applications, but these will likely be overcome by developments in OCT technology [1]. Some factors that have limited adaptation of OCT into the pulmonary setting in the past have been the shallow depth of penetration, resolution limitations, relatively slow access times, need to examine large surface areas with numerous branching airways, motion artifacts, as well as a need for development of practical imaging probes to reach the relevant locations in a minimally invasive way. Considerable recent engineering and analytical advances in OCT technology [2-8] have already overcome several of these obstacles and will enable much more extensive investigations into the role for structural and functional pulmonary OCT imaging [1].

  17. Optical Coherence Tomography: Modeling and Applications

    DEFF Research Database (Denmark)

    Thrane, Lars

    in previous theoretical models of OCT systems. It is demonstrated that the shower curtain effect is of utmost importance in the theoretical description of an OCT system. The analytical model, together with proper noise analysis of the OCT system, enables calculation of the SNR, where the optical properties...... geometry, i.e., reflection geometry, is developed. As in the new OCT model, multiple scattered photons has been taken into account together with multiple scattering effects. As an important result, a novel method of creating images based on measurements of the momentum width of the Wigner phase......An analytical model is presented that is able to describe the performance of OCT systems in both the single and multiple scattering regimes simultaneously. This model inherently includes the shower curtain effect, well-known for light propagation through the atmosphere. This effect has been omitted...

  18. Simultaneous measurement of group refractive index and thickness of optical samples using optical coherence tomography.

    Science.gov (United States)

    Cheng, Hsu-Chih; Liu, Yi-Cheng

    2010-02-10

    Optical coherence tomography (OCT), based on a Michelson interferometer and utilizing low coherence light as the optical source, is a novel technique for the noninvasive imaging of optical scattering media. A simple OCT scheme based on a 3 x 3 fiber coupler is presented for the simultaneous measurement of the refractive index and thickness of optical samples. The proposed system enables the refractive index and thickness to be determined without any prior knowledge of the sample parameters and is characterized by a simple and compact configuration, a straightforward measurement procedure, and a low cost. The feasibility of the proposed approach is demonstrated experimentally using BK7 and B270 optical glass samples.

  19. Simultaneous measurement of group refractive index and thickness of optical samples using optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hsu-Chih; Liu, Yi-Cheng

    2010-02-10

    Optical coherence tomography (OCT), based on a Michelson interferometer and utilizing low coherence light as the optical source, is a novel technique for the noninvasive imaging of optical scattering media. A simple OCT scheme based on a 3x3 fiber coupler is presented for the simultaneous measurement of the refractive index and thickness of optical samples. The proposed system enables the refractive index and thickness to be determined without any prior knowledge of the sample parameters and is characterized by a simple and compact configuration, a straightforward measurement procedure, and a low cost. The feasibility of the proposed approach is demonstrated experimentally using BK7 and B270 optical glass samples.

  20. Detection of coal dust in a mine using optical tomography

    Institute of Scientific and Technical Information of China (English)

    Wei Mingsheng; Tong Minming; Hao Jifei; Cai Li; Xu Jie

    2012-01-01

    A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations are the goal of this method.An optical sensor array is employed to realize an optical sensing field of the coal dust concentration during on-line monitoring.A novel image reconstruction algorithm,called the simultaneous iterative reconstruction technique (SIRT),is compared to the well known linear,back projection algorithm (LBP).The SIRT was applied to the present problem and tested by modeling.The disadvantage of the SIRT is a slow speed but some improvements have been made by adding a weighting function that reduces the relative error to 1.7% from 3.1% for 50 iterations.The results of image reconstruction are presented for both simulated and real objects.They prove that the optical tomography technique,based on a multi-source fan projection scheme,can be an effective approach for estimating coal dust distribution.This system can be applied in real time for continuous measurements in a mine.

  1. Passive endoscopic polarization sensitive optical coherence tomography with completely fiber based optical components

    Science.gov (United States)

    Cahill, Lucas; Lee, Anthony M. D.; Pahlevaninezhad, Hamid; Ng, Samson; MacAulay, Calum E.; Poh, Catherine; Lane, Pierre

    2015-03-01

    Polarization Sensitive Optical Coherence Tomography (PSOCT) is a functional extension of Optical Coherence Tomography (OCT) that is sensitive to well-structured, birefringent tissue such as scars, smooth muscle and cartilage. In this work, we present a novel completely fiber based swept source PSOCT system using a fiber-optic rotary pullback catheter. This PSOCT implementation uses only passive optical components and requires no calibration while adding minimal additional cost to a standard structural OCT imaging system. Due to its complete fiber construction, the system can be made compact and robust, while the fiber-optic catheter allows access to most endoscopic imaging sites. The 1.5mm diameter endoscopic probe can capture 100 frames per second at pullback speeds up to 15 mm/s allowing rapid traversal of large imaging fields. We validate the PSOCT system with known birefringent tissues and demonstrate in vivo PSOCT imaging of human oral scar tissue.

  2. Large area full-field optical coherence tomography

    Science.gov (United States)

    Chang, Shoude; Sherif, Sherif; Flueraru, Costel

    2006-09-01

    Optical Coherence Tomography (OCT) is a fundamentally new type of optical imaging technology. OCT performs high resolution, cross-sectional tomographic imaging of the internal structure in materials and biological systems. The biomedical applications of the OCT imaging systems have been developed for diagnostics of ophthalmology, dermatology, dentistry and cardiology. Most of existing OCT systems use point-scanning based technology, however, the 3-axis scanning makes the system slow and cumbersome. A few OCT systems working directly on 2D full-field images were reported, however, they are designed to work in a relatively small area, around couple of hundred microns square. In this paper, we present a design and implementation of a full-field OCT imaging system for acquiring tomography and with a working area around 15mm by 15 mm. The problems rising from full-field OCT are addressed and analyzed. The algorithms to extract the tomography are proposed. Two applications of multilayer information retrieval and 3D object imaging using full-field OCT are described.

  3. Multispectral guided fluorescence diffuse optical tomography using upconverting nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Svenmarker, Pontus, E-mail: pontus.svenmarker@physics.umu.se [Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Department of Physics, Umeå University, SE-901 87 Umeå (Sweden); Centre for Microbial Research (UCMR), Umeå University, SE-901 87 Umeå (Sweden); Xu, Can T.; Liu, Haichun; Wu, Xia; Andersson-Engels, Stefan [Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden)

    2014-02-17

    We report on improved image detectability for fluorescence diffuse optical tomography using upconverting nanoparticles doped with rare-earth elements. Core-shell NaYF{sub 4}:Yb{sup 3+}/Er{sup 3+}@NaYF{sub 4} upconverting nanoparticles were synthesized through a stoichiometric method. The Yb{sup 3+}/Er{sup 3+} sensitizer-activator pair yielded two anti-Stokes shifted fluorescence emission bands at 540 nm and 660 nm, here used to a priori estimate the fluorescence source depth with sub-millimeter precision. A spatially varying regularization incorporated the a priori fluorescence source depth estimation into the tomography reconstruction scheme. Tissue phantom experiments showed both an improved resolution and contrast in the reconstructed images as compared to not using any a priori information.

  4. CT guided diffuse optical tomography for breast cancer imaging

    Science.gov (United States)

    Baikejiang, Reheman; Zhang, Wei; Zhu, Dianwen; Li, Changqing

    2016-03-01

    Diffuse optical tomography (DOT) has attracted attentions in the last two decades due to its intrinsic sensitivity in imaging chromophores of tissues such as blood, water, and lipid. However, DOT has not been clinically accepted yet due to its low spatial resolution caused by strong optical scattering in tissues. Structural guidance provided by an anatomical imaging modality enhances the DOT imaging substantially. Here, we propose a computed tomography (CT) guided multispectral DOT imaging system for breast cancer detection. To validate its feasibility, we have built a prototype DOT imaging system which consists of a laser at wavelengths of 650 and an electron multiplying charge coupled device (EMCCD) camera. We have validated the CT guided DOT reconstruction algorithms with numerical simulations and phantom experiments, in which different imaging setup parameters, such as projection number of measurements, the width of measurement patch, have been investigated. Our results indicate that an EMCCD camera with air cooling is good enough for the transmission mode DOT imaging. We have also found that measurements at six projections are sufficient for DOT to reconstruct the optical targets with 4 times absorption contrast when the CT guidance is applied. Finally, we report our effort and progress on the integration of the multispectral DOT imaging system into a breast CT scanner.

  5. Miniature endoscopic optical coherence tomography for calculus detection.

    Science.gov (United States)

    Kao, Meng-Chun; Lin, Chun-Li; Kung, Che-Yen; Huang, Yi-Fung; Kuo, Wen-Chuan

    2015-08-20

    The effective treatment of periodontitis involves the detection and removal of subgingival dental calculus. However, subgingival calculus is more difficult to detect than supragingival calculus because it is firmly attached to root surfaces within periodontal pockets. To achieve a smooth root surface, clinicians often remove excessive amounts of root structure because of decreased visibility. In addition, enamel pearl, a rare type of ectopic enamel formation on the root surface, can easily be confused with dental calculus in the subgingival environment. In this study, we developed a fiber-probe swept-source optical coherence tomography (SSOCT) technique and combined it with the quantitative measurement of an optical parameter [standard deviation (SD) of the optical coherence tomography (OCT) intensity] to differentiate subgingival calculus from sound enamel, including enamel pearl. Two-dimensional circumferential images were constructed by rotating the miniprobe (0.9 mm diameter) while acquiring image lines, and the adjacent lines in each rotation were stacked to generate a three-dimensional volume. In OCT images, compared to sound enamel and enamel pearls, dental calculus showed significant differences (Pcalculus.

  6. Optical Coherence Tomography as a Tool for Ocular Dynamics Estimation

    Directory of Open Access Journals (Sweden)

    Damian Siedlecki

    2015-01-01

    Full Text Available Purpose. The aim of the study is to demonstrate that the ocular dynamics of the anterior chamber of the eye can be estimated quantitatively by means of optical coherence tomography (OCT. Methods. A commercial high speed, high resolution optical coherence tomographer was used. The sequences of tomographic images of the iridocorneal angle of three subjects were captured and each image from the sequence was processed in MATLAB environment in order to detect and identify the contours of the cornea and iris. The data on pulsatile displacements of the cornea and iris and the changes of the depth of the gap between them were retrieved from the sequences. Finally, the spectral analysis of the changes of these parameters was performed. Results. The results of the temporal and spectral analysis manifest the ocular microfluctuation that might be associated with breathing (manifested by 0.25 Hz peak in the power spectra, heart rate (1–1.5 Hz peak, and ocular hemodynamics (3.75–4.5 Hz peak. Conclusions. This paper shows that the optical coherence tomography can be used as a tool for noninvasive estimation of the ocular dynamics of the anterior segment of the eye, but its usability in diagnostics of the ocular hemodynamics needs further investigations.

  7. Fourier phase in Fourier-domain optical coherence tomography.

    Science.gov (United States)

    Uttam, Shikhar; Liu, Yang

    2015-12-01

    Phase of an electromagnetic wave propagating through a sample-of-interest is well understood in the context of quantitative phase imaging in transmission-mode microscopy. In the past decade, Fourier-domain optical coherence tomography has been used to extend quantitative phase imaging to the reflection-mode. Unlike transmission-mode electromagnetic phase, however, the origin and characteristics of reflection-mode Fourier phase are poorly understood, especially in samples with a slowly varying refractive index. In this paper, the general theory of Fourier phase from first principles is presented, and it is shown that Fourier phase is a joint estimate of subresolution offset and mean spatial frequency of the coherence-gated sample refractive index. It is also shown that both spectral-domain phase microscopy and depth-resolved spatial-domain low-coherence quantitative phase microscopy are special cases of this general theory. Analytical expressions are provided for both, and simulations are presented to explain and support the theoretical results. These results are further used to show how Fourier phase allows the estimation of an axial mean spatial frequency profile of the sample, along with depth-resolved characterization of localized optical density change and sample heterogeneity. Finally, a Fourier phase-based explanation of Doppler optical coherence tomography is also provided.

  8. Optical coherence tomography imaging of ocular and periocular tumours

    Science.gov (United States)

    Medina, Carlos A; Plesec, Thomas; Singh, Arun D

    2014-01-01

    Optical coherence tomography (OCT) has become pivotal in the practice of ophthalmology. Similar to other ophthalmic subspecialties, ophthalmic oncology has also incorporated OCT into practice. Anterior segment OCT (AS-OCT), ultra-high resolution OCT (UHR-OCT), spectral domain OCT (SD-OCT) and enhanced depth imaging OCT (EDI-OCT), have all been described to be helpful in the diagnosis, treatment planning and monitoring response of ocular and periocular tumours. Herein we discuss the role of OCT including the advantages and limitations of its use in the setting of common intraocular and adnexal tumours. PMID:24599420

  9. Optical diffraction tomography techniques for the study of cell pathophysiology

    CERN Document Server

    Kim, Kyoohyun; Shin, Seungwoo; Lee, SangYun; Yang, Su-A; Park, YongKeun

    2016-01-01

    Three-dimensional imaging of biological cells is crucial for the investigation of cell biology, provide valuable information to reveal the mechanisms behind pathophysiology of cells and tissues. Recent advances in optical diffraction tomography (ODT) have demonstrated the potential for the study of various cells with its unique advantages of quantitative and label-free imaging capability. To provide insight on this rapidly growing field of research and to discuss its applications in biology and medicine, we present the summary of the ODT principle and highlight recent studies utilizing ODT with the emphasis on the applications to the pathophysiology of cells.

  10. Primate retina imaging with polarization-sensitive optical coherence tomography

    Science.gov (United States)

    Ducros, Mathieu G.; Marsack, Jason D.; Rylander, H. Grady; Thomsen, Sharon L.; Milner, Thomas E.

    2001-12-01

    Polarization-sensitive optical coherence tomography (PSOCT) is applied to determine the depth-resolved polarization state of light backreflected from the eye. The birefringence of the retinal nerve fiber layer (RNFL) was observed and measured from PSOCT images recorded postmortem in a Rhesus monkey. An image-processing algorithm was developed to identify birefringent regions in acquired PSOCT retinal images and automatically determine the thickness of the RNFL. Values of the RNFL thickness determined from histology and PSOCT were compared. PSOCT may provide a new method to determine RNFL thickness and birefringence for glaucoma diagnostics.

  11. Ultrasound-Modulated Optical Tomography in Reflective and Coaxial Configuration

    Institute of Scientific and Technical Information of China (English)

    傅洪波; 邢达; 曾亚光; 王毅; 陈群

    2003-01-01

    Ultrasound-modulated optical tomography affords a very promising noninvasive imaging method for biomedical diagnosis. With this technique, an ultrasound beam is focused into a scattering medium to provide an accurate localization and, simultaneously, a modulation of laser light inside the medium. Based on the high-sensitivity detection technique, we have developed a unique reflective configuration, which was more convenient and practical than other existing configurations. Furthermore, the configuration also introduced a new scheme to improve the spatial resolution in the imaging. A phantom was imaged to validate the feasibility of the proposed configuration.

  12. High Speed Optical Tomography System for Imaging Dynamic Transparent Media

    Science.gov (United States)

    McMackin, Lenore; Hugo, Ronald J.; Pierson, R. E.; Truman, C. R.

    1997-11-01

    We describe the design and operation of a high speed optical tomography system for measuring two-dimensional images of a dynamic phase object at a rate of 5 kHz. Data from a set of eight Hartmann wavefront sensors is back-projected to produce phase images showing the details of the inner structure of a heated air flow. The tomographic reconstructions have a spatial resolution of approximately 2.0 mm and can measure temperature variations across the flow with an accuracy of about 0.7 C. Series of animated reconstructions at different downstream locations illustrate the development of flow structure and the effect of acoustic flow forcing.

  13. Single fiber perfusion phantom for optical coherence tomography

    Science.gov (United States)

    Podlipná, Petra; Kolář, Radim

    2013-06-01

    This paper presents the successful creation of new phantom for optical coherence tomography (OCT) aimed on perfusion simulation. The phantom is created from syringe pump and polypropylene hollow fiber with porous walls embeded in the glass capillary to provide small outer environment. Its function was tested by gold nanorods as a flowing medium and imaged by commercial swept-source OCT system. Results showed that the fiber is permeable for used gold nanorods which are frequently declared as possible contrast agents for OCT and this permeability can be displayed by OCT.

  14. All-optically integrated multimodality imaging system: combined photoacoustic microscopy, optical coherence tomography, and fluorescence imaging

    Science.gov (United States)

    Chen, Zhongjiang; Yang, Sihua; Xing, Da

    2016-10-01

    We have developed a multimodality imaging system by optically integrating all-optical photoacoustic microscopy (AOPAM), optical coherence tomography (OCT) and fluorescence microscopy (FLM) to provide complementary information including optical absorption, optical back-scattering and fluorescence contrast of biological tissue. By sharing the same low-coherence Michelson interferometer, AOPAM and OCT could be organically optically combined to obtain the absorption and scattering information of the biological tissues. Also, owing to using the same laser source and objective lens, intrinsically registered photoacoustic and fluorescence signals are obtained to present the radiative and nonradiative transition process of absorption. Simultaneously photoacoustic angiography, tissue structure and fluorescence molecular in vivo images of mouse ear were acquired to demonstrate the capabilities of the optically integrated trimodality imaging system, which can present more information to study tumor angiogenesis, vasculature, anatomical structure and microenvironments in vivo.

  15. Optical tractography of the mouse heart using polarization-sensitive optical coherence tomography.

    Science.gov (United States)

    Wang, Yuanbo; Yao, Gang

    2013-01-01

    We developed a method to image myocardial fiber architecture in the mouse heart using a Jones matrix-based polarization-sensitive optical coherence tomography (PSOCT) system. The "cross-helical" laminar structure of myocardial fibers can be clearly visualized using this technology. The obtained myocardial fiber organization agrees well with existing knowledge acquired using conventional histology and diffusion tensor magnetic resonance imaging.

  16. Quantitative characterization of developing collagen gels using optical coherence tomography

    Science.gov (United States)

    Levitz, David; Hinds, Monica T.; Choudhury, Niloy; Tran, Noi T.; Hanson, Stephen R.; Jacques, Steven L.

    2010-03-01

    Nondestructive optical imaging methods such as optical coherence tomography (OCT) have been proposed for characterizing engineered tissues such as collagen gels. In our study, OCT was used to image collagen gels with different seeding densities of smooth muscle cells (SMCs), including acellular gels, over a five-day period during which the gels contracted and became turbid with increased optical scattering. The gels were characterized quantitatively by their optical properties, specified by analysis of OCT data using a theoretical model. At 6 h, seeded cell density and scattering coefficient (μs) were correlated, with μs equal to 10.8 cm-1/(106 cells/mL). Seeded cell density and the scattering anisotropy (g) were uncorrelated. Over five days, the reflectivity in SMC gels gradually doubled with little change in optical attenuation, which indicated a decrease in g that increased backscatter, but only a small drop in μs. At five days, a subpopulation of sites on the gel showed substantially higher reflectivity (approximately a tenfold increase from the first 24 h). In summary, the increased turbidity of SMC gels that develops over time is due to a change in the structure of collagen, which affects g, and not simply due to a change in number density of collagen fibers due to contraction.

  17. Monte Carlo Simulations of Arterial Imaging with Optical Coherence Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, P.; Estabrook, K.; Everett, M.; London, R.A.; Maitland, D.; Zimmerman, G.; Colston, B.; da Silva, L.; Sathyam, U.

    2000-02-01

    The laser-tissue interaction code LATIS [London et al., Appl. Optics 36, 9068 ( 1998)] is used to analyze photon scattering histories representative of optical coherence tomography (OCT) experiment performed at Lawrence Livermore National Laboratory. Monte Carlo photonics with Henyey-Greenstein anisotropic scattering is implemented and used to simulate signal discrimination of intravascular structure. An analytic model is developed and used to obtain a scaling law relation for optimization of the OCT signal and to validate Monte Carlo photonics. The appropriateness of the Henyey-Greenstein phase function is studied by direct comparison with more detailed Mie scattering theory using an ensemble of spherical dielectric scatterers. Modest differences are found between the two prescriptions for describing photon angular scattering in tissue. In particular, the Mie scattering phase functions provide less overall reflectance signal but more signal contrast compared to the Henyey-Greenstein formulation.

  18. Optical coherence tomography a clinical and technical update

    CERN Document Server

    Cunha-Vaz, José

    2012-01-01

    Optical Coherence Tomography represents the ultimate noninvasive  ocular imaging technique although being in the field for over two-decades. This book encompasses both medical and technical developments and recent achievements. Here, the authors cover the field of application from the anterior to the posterior ocular segments (Part I) and present a comprehensive review on the development of OCT. Important developments towards  clinical applications are covered in Part II, ranging from the adaptive optics to the integration on a slit-lamp, and passing through new structural  and functional information extraction from OCT data. The book is intended to be informative, coherent and comprehensive for both the medical and technical communities and aims at easing the communication between the two fields and bridging the gap between the two scientific communities.

  19. Imaging of oral pathological tissue using optical coherence tomography

    Science.gov (United States)

    Canjau, Silvana; Todea, Carmen; Sinescu, Cosmin; Duma, Virgil-Florin; Topala, Florin I.; Podoleanu, Adrian G.

    2014-01-01

    Oral squamous cell carcinoma (OSCC) constitutes 90% of oral cancer. Early detection is a cornerstone to improve survival. Interaction of light with tissues may highlight changes in tissue structure and metabolism. We propose optical coherence tomography (OCT), as a non-invasive diagnosis method, being a new high-resolution optical technique that permits tri-dimensional (3-D), real-time imaging of near surface abnormalities in complex tissues. In this study half of the excisional biopsy was directed to the pathologist and the other half was assigned for OCT investigation. Histopathology validated the results. Areas of OSCC of the buccal mucosa were identified in the OCT images. The elements obserced included extensive epithelial down-growth, the disruption of the basement membrane, with areas of erosion, an epithelial layer that was highly variable in thickness and invasion into the sub-epithelial layers. Therefore, OCT appears to be a highly promising imaging modality.

  20. Non-diffusing photochromic gel for optical computed tomography phantoms

    Science.gov (United States)

    Jordan, K.

    2013-06-01

    This study examines photochromic response in radiation sensitive hydrogels. Genipin, crosslinked, gelatin gel can support high resolution images because the chromophores do not diffuse. A low power, 633 nm He-Ne laser was used to write lines into the gels by a photobleaching reaction. Optical cone-beam computed tomography (CBCT) scans mapped the high resolution images in 3D with 0.25 mm voxel resolution. A straight line was written into a deformed gel and then readout in its relaxed, initial shape. The curved, photo-bleached line demonstrated deformable 3D dosimetry is possible with this system to the balloon edge. High resolution, photochromic images provide key information for characterizing optical CT scanners and 3D dosimeters. Many, ionizing radiation, dosimeter materials demonstrate either a photochromic or photothermal response, allowing this approach to be widely used in quantitative 3D scanning.

  1. Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

    Science.gov (United States)

    Zabihian, Behrooz; Chen, Zhe; Rank, Elisabet; Sinz, Christoph; Bonesi, Marco; Sattmann, Harald; Ensher, Jason; Minneman, Michael P.; Hoover, Erich; Weingast, Jessika; Ginner, Laurin; Leitgeb, Rainer; Kittler, Harald; Zhang, Edward; Beard, Paul; Drexler, Wolfgang; Liu, Mengyang

    2016-09-01

    Studies have proven the relationship between cutaneous vasculature abnormalities and dermatological disorders, but to image vasculature noninvasively in vivo, advanced optical imaging techniques are required. In this study, we imaged a palm of a healthy volunteer and three subjects with cutaneous abnormalities with photoacoustic tomography (PAT) and optical coherence tomography with angiography extension (OCTA). Capillaries in the papillary dermis that are too small to be discerned with PAT are visualized with OCTA. From our results, we speculate that the PA signal from the palm is mostly from hemoglobin in capillaries rather than melanin, knowing that melanin concentration in volar skin is significantly smaller than that in other areas of the skin. We present for the first time OCTA images of capillaries along with the PAT images of the deeper vessels, demonstrating the complementary effective imaging depth range and the visualization capabilities of PAT and OCTA for imaging human skin in vivo. The proposed imaging system in this study could significantly improve treatment monitoring of dermatological diseases associated with cutaneous vasculature abnormalities.

  2. Subluxed traumatic cataract: optical coherence tomography findings and clinical management

    Directory of Open Access Journals (Sweden)

    Kuriyan AE

    2012-12-01

    Full Text Available Ajay E Kuriyan, Harry W Flynn Jr, Sonia H YooDepartment of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, FLAbstract: This case report describes the optical coherence tomography (OCT findings and clinical management of a patient with traumatic subluxed cataract. The patient presented with a traumatic subluxed cataract and vitreous prolapse into the anterior chamber. The anterior segment OCT showed vacuoles in the anterior subcapsular regions of the crystalline lens. The patient was treated with pars plana lensectomy, vitrectomy, and placement of an anterior chamber intraocular lens. The patient's best corrected visual acuity improved from hand motion at presentation to 20/25 during 3 years of follow-up. Anterior segment OCT demonstrates that the clinically visible vacuoles in traumatic cataract are located in the anterior subcapsular part of the lens. This is the first report in the literature using anterior segment OCT to visualize the subcapsular vacuolar changes in a traumatic cataract.Keywords: traumatic cataract, subluxed lens, vacuoles, anterior chamber intraocular lens, anterior segment optical coherence tomography

  3. High-speed optical coherence tomography signal processing on GPU

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiqi; Shi Guohua; Zhang Yudong, E-mail: lixiqi@yahoo.cn [Laboratory on Adaptive Optics, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209 (China)

    2011-01-01

    The signal processing speed of spectral domain optical coherence tomography (SD-OCT) has become a bottleneck in many medical applications. Recently, a time-domain interpolation method was proposed. This method not only gets a better signal-to noise ratio (SNR) but also gets a faster signal processing time for the SD-OCT than the widely used zero-padding interpolation method. Furthermore, the re-sampled data is obtained by convoluting the acquired data and the coefficients in time domain. Thus, a lot of interpolations can be performed concurrently. So, this interpolation method is suitable for parallel computing. An ultra-high optical coherence tomography signal processing can be realized by using graphics processing unit (GPU) with computer unified device architecture (CUDA). This paper will introduce the signal processing steps of SD-OCT on GPU. An experiment is performed to acquire a frame SD-OCT data (400A-linesx2048 pixel per A-line) and real-time processed the data on GPU. The results show that it can be finished in 6.208 milliseconds, which is 37 times faster than that on Central Processing Unit (CPU).

  4. Optical coherence tomography for retinal imaging in multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Zimmermann H

    2014-12-01

    Full Text Available Hanna Zimmermann,1 Timm Oberwahrenbrock,1 Alexander U Brandt,1 Friedemann Paul,1–3 Jan Dörr1,2 1NeuroCure Clinical Research Center, 2Clinical and Experimental Multiple Sclerosis Research Center, 3Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany Abstract: Visual disturbances caused by inflammatory and demyelinating processes of the visual system, mainly in the optic nerve, are a common symptom in multiple sclerosis (MS. Optical coherence tomography (OCT is a tool that is increasingly used for quantifying retinal damage in MS and other neurologic diseases. Based on spectral interferometry, it uses low-coherent infrared light to generate high-resolution spatial images of the retina. The retinal nerve fiber layer (RNFL consists of unmyelinated axons that form the optic nerve, and thus represents a part of the central nervous system. OCT allows for noninvasive measurements of RNFL thickness in micrometer resolution. With the help of OCT, researchers have managed to demonstrate that eyes of MS patients show distinct RNFL thinning after an event of acute optic neuritis in MS, and even subclinical damage in eyes with no previous optic neuritis. OCT is also a useful tool in terms of providing a differential diagnosis of MS toward, for example, neuromyelitis optica, a disease that usually shows stronger retinal thinning, or Susac syndrome, which is characterized by distinct patchy thinning of the inner retinal layers. RNFL thinning is associated with magnetic resonance imaging-derived measurements of the brain, such as whole-brain atrophy, gray and white matter atrophy, and optic radiation damage. These features suggest that OCT-derived retinal measurements are a complement for measuring central nervous system neurodegeneration in the context of clinical trials – for example, with neuroprotective substances. Keywords: visual function, multiple sclerosis, optic neuritis, retinal nerve fiber layer, neuromyelitis optica

  5. A 5° medial wedge reduces frontal but not saggital plane motion during jump landing in highly trained women athletes

    Directory of Open Access Journals (Sweden)

    Michael F Joseph

    2010-03-01

    Full Text Available Michael F Joseph1, Craig R Denegar1, Elaine Horn1, Bradley MacDougall1, Michael Rahl1, Jessica Sheehan1, Thomas Trojian2, Jeffery M Anderson1, James E Clark1, William J Kraemer11Department of Kinesiology, 2Department of Sports Medicine, University of Connecticut, Storrs, CT, USAAbstract: Lower extremity mechanics during landing have been linked to traumatic and nontraumatic knee injuries, particularly in women’s athletics. The effects of efforts to mitigate these risks have not been fully elucidated. We previously reported that a 5° medial wedge reduced ankle eversion and knee valgus. In the present report we further investigated the effect of a 5° medial wedge inserted in the shoes of female athletes on frontal plane hip motion, as well as ankle, knee, hip, and trunk saggital plane motion during a jump landing task. Kinematic data were obtained from 10 intercollegiate female athletes during jump landings from a 31 cm platform with and without a 5° medial wedge. Hip adduction was reduced 1.98° (95% CI 0.97–2.99° by the medial wedge but saggital plane motions were unaffected. A 5° medial wedge reduces frontal plane motion and takes the knee away from a position associated with anterior cruciate ligament injury and patellofemoral pain syndrome. Although frontal plane motion was not captured it is unlikely to have increased in a bilateral landing task. Thus, it is likely that greater muscle forces were generated in these highly trained athletes to dissipate ground reaction forces when a medial wedge was in place. Additional investigation in younger and lesser trained athletes is warranted to assess the impact of orthotic devices on knee joint mechanics.Keywords: jump landing, foot orthotic, lower extremity kinematics, knee biomechanics, knee injury

  6. Collaborative effects of wavefront shaping and optical clearing agent in optical coherence tomography

    CERN Document Server

    Yu, Hyeonseung; Jo, YoungJu; Lee, KyeoReh; Tuchin, Valery V; Jeong, Yong; Park, YongKeun

    2016-01-01

    We demonstrate that simultaneous application of optical clearing agents (OCAs) and complex wavefront shaping in optical coherence tomography (OCT) can provide significant enhancement of the penetration depth and imaging quality. OCA reduces optical inhomogeneity of a highly scattering sample, and the wavefront shaping of illumination light controls multiple scattering, resulting in an enhancement of the penetration depth and signal-to-noise ratio. A tissue phantom study shows that concurrent applications of OCA and wavefront shaping successfully operate in OCT imaging. The penetration depth enhancement is further demonstrated for ex vivo mouse ears, revealing hidden structures inaccessible with conventional OCT imaging.

  7. Cellular resolution volumetric in vivo retinal imaging with adaptive optics-optical coherence tomography.

    Science.gov (United States)

    Zawadzki, Robert J; Choi, Stacey S; Fuller, Alfred R; Evans, Julia W; Hamann, Bernd; Werner, John S

    2009-03-02

    Ultrahigh-resolution adaptive optics-optical coherence tomography (UHR-AO-OCT) instrumentation allowing monochromatic and chromatic aberration correction was used for volumetric in vivo retinal imaging of various retinal structures including the macula and optic nerve head (ONH). Novel visualization methods that simplify AO-OCT data viewing are presented, and include co-registration of AO-OCT volumes with fundus photography and stitching of multiple AO-OCT sub-volumes to create a large field of view (FOV) high-resolution volume. Additionally, we explored the utility of Interactive Science Publishing by linking all presented AO-OCT datasets with the OSA ISP software.

  8. High-resolution retinal imaging using adaptive optics and Fourier-domain optical coherence tomography

    Science.gov (United States)

    Olivier, Scot S.; Werner, John S.; Zawadzki, Robert J.; Laut, Sophie P.; Jones, Steven M.

    2010-09-07

    This invention permits retinal images to be acquired at high speed and with unprecedented resolution in three dimensions (4.times.4.times.6 .mu.m). The instrument achieves high lateral resolution by using adaptive optics to correct optical aberrations of the human eye in real time. High axial resolution and high speed are made possible by the use of Fourier-domain optical coherence tomography. Using this system, we have demonstrated the ability to image microscopic blood vessels and the cone photoreceptor mosaic.

  9. Developing High-Density Diffuse Optical Tomography for Neuroimaging

    Science.gov (United States)

    White, Brian Richard

    Clinicians who care for brain-injured patients and premature infants desire a bedside monitor of brain function. A decade ago, there was hope that optical imaging would be able to fill this role, as it combined fMRI's ability to construct cortical maps with EEG's portable, cap-based systems. However, early optical systems had poor imaging performance, and the momentum for the technique slowed. In our lab, we develop diffuse optical tomography (DOT), which is a more advanced method of performing optical imaging. My research has been to pioneer the in vivo use of DOT for advanced neuroimaging by (1) quantifying the advantages of DOT through both in silico simulation and in vivo performance metrics, (2) restoring confidence in the technique with the first retinotopic mapping of the visual cortex (a benchmark for fMRI and PET), and (3) creating concepts and methods for the clinical translation of DOT. Hospitalized patients are unable to perform complicated neurological tasks, which has motivated us to develop the first DOT methods for resting-state brain mapping with functional connectivity. Finally, in collaboration with neonatologists, I have extended these methods with proof-of-principle imaging of brain-injured premature infants. This work establishes DOT's improvements in imaging performance and readies it for multiple clinical and research roles.

  10. Overview of diffuse optical tomography and its clinical applications

    Science.gov (United States)

    Hoshi, Yoko; Yamada, Yukio

    2016-09-01

    Near-infrared diffuse optical tomography (DOT), one of the most sophisticated optical imaging techniques for observations through biological tissue, allows 3-D quantitative imaging of optical properties, which include functional and anatomical information. With DOT, it is expected to be possible to overcome the limitations of conventional near-infrared spectroscopy (NIRS) as well as offering the potential for diagnostic optical imaging. However, DOT has been under development for more than 30 years, and the difficulties in development are attributed to the fact that light is strongly scattered and that diffusive photons are used for the image reconstruction. The DOT algorithm is based on the techniques of inverse problems. The radiative transfer equation accurately describes photon propagation in biological tissue, while, because of its high computation load, the diffusion equation (DE) is often used as the forward model. However, the DE is invalid in low-scattering and/or highly absorbing regions and in the vicinity of light sources. The inverse problem is inherently ill-posed and highly undetermined. Here, we first summarize NIRS and then describe various approaches in the efforts to develop accurate and efficient DOT algorithms and present some examples of clinical applications. Finally, we discuss the future prospects of DOT.

  11. Optical coherence tomography segmentation reveals ganglion cell layer pathology after optic neuritis.

    Science.gov (United States)

    Syc, Stephanie B; Saidha, Shiv; Newsome, Scott D; Ratchford, John N; Levy, Michael; Ford, E'tona; Crainiceanu, Ciprian M; Durbin, Mary K; Oakley, Jonathan D; Meyer, Scott A; Frohman, Elliot M; Calabresi, Peter A

    2012-02-01

    Post-mortem ganglion cell dropout has been observed in multiple sclerosis; however, longitudinal in vivo assessment of retinal neuronal layers following acute optic neuritis remains largely unexplored. Peripapillary retinal nerve fibre layer thickness, measured by optical coherence tomography, has been proposed as an outcome measure in studies of neuroprotective agents in multiple sclerosis, yet potential swelling during the acute stages of optic neuritis may confound baseline measurements. The objective of this study was to ascertain whether patients with multiple sclerosis or neuromyelitis optica develop retinal neuronal layer pathology following acute optic neuritis, and to systematically characterize such changes in vivo over time. Spectral domain optical coherence tomography imaging, including automated retinal layer segmentation, was performed serially in 20 participants during the acute phase of optic neuritis, and again 3 and 6 months later. Imaging was performed cross-sectionally in 98 multiple sclerosis participants, 22 neuromyelitis optica participants and 72 healthy controls. Neuronal thinning was observed in the ganglion cell layer of eyes affected by acute optic neuritis 3 and 6 months after onset (P optica, with and without a history of optic neuritis, when compared with healthy controls (P optica and a history of optic neuritis exhibited the greatest reduction in ganglion cell layer thickness. Results from our in vivo longitudinal study demonstrate retinal neuronal layer thinning following acute optic neuritis, corroborating the hypothesis that axonal injury may cause neuronal pathology in multiple sclerosis. Further, these data provide evidence of subclinical disease activity, in both participants with multiple sclerosis and with neuromyelitis optica without a history of optic neuritis, a disease in which subclinical disease activity has not been widely appreciated. No pathology was seen in the inner or outer nuclear layers of eyes with optic

  12. Optical coherence tomography findings and retinal changes after vitrectomy for optic disc pit maculopathy

    Directory of Open Access Journals (Sweden)

    Gaurav Sanghi

    2014-01-01

    Full Text Available Purpose : To study the optical coherence tomography (OCT patterns in optic disc pit maculopathy and retinal changes after vitreous surgery. Materials and Methods : Retrospective review of consecutive cases with optic disc pit maculopathy seen at two tertiary eye institutes from January 2005 to June 2009. Results : Twenty-four eyes of 23 patients are included. The presenting visual acuity ranged from 20/400 to 20/20 (median:20/80. The median age at presentation was 24 years (range, 6-57 years. Optical coherence tomography demonstrated a combination of retinoschisis and outer layer detachment (OLD in 19 (79.17% eyes, OLD only in 3 (12.5% eyes and retinoschisis only in 2 (8.33% eyes. An obvious communication (outer layer hole between the schisis and OLD was seen in 14 (73.68% of the 19 eyes with both features. Of the 21 eyes with retinoschisis, schisis was present in multiple layers in 15 (71.43% and single layer in 6 (28.57% eyes. Eleven eyes underwent pars plana vitrectomy including creation of posterior vitreous detachment (PVD, fluid-air exchange, low intensity laser photocoagulation at the temporal edge of the optic disc pit and non-expansile perfluoropropane gas (14% injection. Five (45.45% of 11 eyes undergoing vitrectomy had complete resolution and 4 (36.36% eyes had partial resolution of maculopathy. Visual acuity improved in 8 (72.72% of 11 eyes. Conclusion : Optical coherence tomography demonstrates multiple layer schisis and outer layer detachment as main features of optic disc pit maculopathy. Vitrectomy with PVD induction, laser photocoagulation and gas tamponade results in anatomical and visual improvement in most cases with optic disc pit maculopathy.

  13. Integrated modeling of the GMT laser tomography adaptive optics system

    Science.gov (United States)

    Piatrou, Piotr

    2014-08-01

    Laser Tomography Adaptive Optics (LTAO) is one of adaptive optics systems planned for the Giant Magellan Telescope (GMT). End-to-end simulation tools that are able to cope with the complexity and computational burden of the AO systems to be installed on the extremely large telescopes such as GMT prove to be an integral part of the GMT LTAO system development endeavors. SL95, the Fortran 95 Simulation Library, is one of the software tools successfully used for the LTAO system end-to-end simulations. The goal of SL95 project is to provide a complete set of generic, richly parameterized mathematical models for key elements of the segmented telescope wavefront control systems including both active and adaptive optics as well as the models for atmospheric turbulence, extended light sources like Laser Guide Stars (LGS), light propagation engines and closed-loop controllers. The library is implemented as a hierarchical collection of classes capable of mutual interaction, which allows one to assemble complex wavefront control system configurations with multiple interacting control channels. In this paper we demonstrate the SL95 capabilities by building an integrated end-to-end model of the GMT LTAO system with 7 control channels: LGS tomography with Adaptive Secondary and on-instrument deformable mirrors, tip-tilt and vibration control, LGS stabilization, LGS focus control, truth sensor-based dynamic noncommon path aberration rejection, pupil position control, SLODAR-like embedded turbulence profiler. The rich parameterization of the SL95 classes allows to build detailed error budgets propagating through the system multiple errors and perturbations such as turbulence-, telescope-, telescope misalignment-, segment phasing error-, non-common path-induced aberrations, sensor noises, deformable mirror-to-sensor mis-registration, vibration, temporal errors, etc. We will present a short description of the SL95 architecture, as well as the sample GMT LTAO system simulation

  14. Non-Contact Optical Fluorescence Tomography for Small Animal Imaging: System Development and Multispectral Applications

    OpenAIRE

    2010-01-01

    Optical Fluorescence Tomography (OFT) of live small animals can yield optimum 3-dimensional imaging performance when large amounts of tomographic boundary information are used for reconstruction. Commonly, multiple source-detector projection measurements distributed over the tissue surface of the imaging object are used to generate raw data for tomography. Recent advances in multispectral optical tomography, however, provide an attractive alternative method to harness tomographic boundary dat...

  15. Monitoring changes of optical attenuation coefficients of acupuncture points during laser acupuncture by optical coherence tomography

    Science.gov (United States)

    Huang, Yimei; Yang, Hongqin; Wang, Yuhua; Zheng, Liqin; Xie, Shusen

    2010-11-01

    The physical properties of acupuncture point were important to discover the mechanism of acupuncture meridian. In this paper, we used an optical coherence tomography to monitor in vivo the changes of optical attenuation coefficients of Hegu acupuncture point and non-acupuncture point during laser irradiation on Yangxi acupuncture point. The optical attenuation coefficients of Hegu acupuncture point and non-acupuncture point were obtained by fitting the raw data according to the Beer-Lambert's law. The experimental results showed that the optical attenuation coefficient of Hegu acupuncture point decreased during the laser acupuncture, in contrast to a barely changed result in that of non-acupuncture point. The significant change of optical attenuation coefficient of Hegu acupuncture point indicated that there was a correlation between Hegu and Yangxi acupuncture points to some extent.

  16. Comparison of diffuse optical tomography of human breast with whole-body and breast-only positron emission tomography

    OpenAIRE

    Konecky, Soren D.; Choe, Regine; Corlu, Alper; Lee, Kijoon; Wiener, Rony; Srinivas, Shyam M.; Saffer, Janet R.; FREIFELDER, RICHARD; Karp, Joel S.; Hajjioui, Nassim; Azar, Fred; Yodh, Arjun G.

    2008-01-01

    We acquire and compare three-dimensional tomographic breast images of three females with suspicious masses using diffuse optical tomography (DOT) and positron emission tomography (PET). Co-registration of DOT and PET images was facilitated by a mutual information maximization algorithm. We also compared DOT and whole-body PET images of 14 patients with breast abnormalities. Positive correlations were found between total hemoglobin concentration and tissue scattering measured by DOT, and fluor...

  17. Miniature optical coherence tomography system based on silicon photonics

    Science.gov (United States)

    Margallo-Balbás, Eduardo; Pandraud, Gregory; French, Patrick J.

    2008-02-01

    Optical Coherence Tomography (OCT) is a promising medical imaging technique. It has found applications in many fields of medicine and has a large potential for the optical biopsy of tumours. One of the technological challenges impairing faster adoption of OCT is the relative complexity of the optical instrumentation required, which translates into expensive and bulky setups. In this paper we report an implementation of Time Domain OCT (TD-OCT) based on a silicon photonic platform. The devices are fabricated using Silicon-On-Insulator (SOI) wafers, on which rib waveguides are defined. While most of the components needed are well-known in this technology, a fast delay line with sufficient scanning range is a specific requirement of TD-OCT. In the system reported, this was obtained making use of the thermo-optical effect of silicon. By modulating the thermal resistance of the waveguide to the substrate, it is possible to establish a trade-off between maximum working frequency and power dissipation. Within this trade-off, the systems obtained can be operated in the kHz range, and they achieve temperature shifts corresponding to scanning ranges of over 2mm. Though the current implementation still requires external sources and detectors to be coupled to the Planar Lightwave Circuit (PLC), future work will include three-dimensional integration of these components onto the substrate. With the potential to include the read-out and driving electronics on the same die, the reported approach can yield extremely compact and low-cost TD-OCT systems, enabling a wealth of new applications, including gastrointestinal pills with optical biopsy capabilities.

  18. Handheld probes and galvanometer scanning for optical coherence tomography

    Science.gov (United States)

    Duma, V.-F.; Dobre, G.; Demian, D.; Cernat, R.; Sinescu, C.; Topala, F. I.; Negrutiu, M. L.; Hutiu, Gh.; Bradu, A.; Rolland, J. P.; Podoleanu, A. G.

    2015-09-01

    As part of the ongoing effort of the biomedical imaging community to move Optical Coherence Tomography (OCT) systems from the lab to the clinical environment and produce OCT systems appropriate for multiple types of investigations in a medical department, handheld probes equipped with different types of scanners need to be developed. These allow different areas of a patient's body to be investigated using OCT with the same system and even without changing the patient's position. This paper reviews first the state of the art regarding OCT handheld probes. Novel probes with a uni-dimensional (1D) galvanometer-based scanner (GS) developed in our groups are presented. Their advantages and limitations are discussed. Aspects regarding the use of galvoscanners with regard to Micro-Electro- Mechanical Systems (MEMS) are pointed out, in relationship with our studies on optimal scanning functions of galvanometer devices in OCT. These scanning functions are briefly discussed with regard to their main parameters: profile, theoretical duty cycle, scan frequency, and scan amplitude. The optical design of the galvoscanner and refractive optics combination in the probe head, optimized for various applications, is considered. Perspectives of the field are pointed out in the final part of the paper.

  19. Optical Coherence Tomography in Patients with Chiari I Malformation

    Directory of Open Access Journals (Sweden)

    Michele Figus

    2015-01-01

    Full Text Available Background/Aims. To evaluate optic nerve head with spectral domain optical coherence tomography (OCT in patients with Chiari I malformation (CMI compared to healthy controls. Methods. Cross-sectional study. OCT of the optic nerve head of 22 patients with CMI and 22 healthy controls was quantitatively analyzed. The healthy controls were matched for age and sex with the study population. Mean retinal nerve fiber layer (RNFL thickness was calculated for both eyes; the mean thickness value was also registered for each quadrant and for each subfield of the four quadrants. Results. CMI patients showed a reduction of the RNFL thickness in both eyes. This reduction was more statistically significant (P<0.05 for the inferior quadrant in the right eye and in each quadrant than nasal one in the left eye. Conclusion. A distress of the retinal nerve fibers could explain the observed reduction of the RNFL thickness in patients with CMI; in our series the reduction of the RNFL thickness seems lower when CMI is associated with syringomyelia.

  20. Full-field optical coherence tomography apply in sphere measurements

    Science.gov (United States)

    Shi, Wei; Li, Weiwei; li, Juncheng; Wang, Jingyu; Wang, Jianguo

    2016-10-01

    The geometry of a spherical surface, for example that of a precision optic, is completely determined by the radius -of-curvature at one point and the deviation from the perfect spherical form at all other points of the sphere. Full-field Optical Coherence Tomography (FF-OCT) is a parallel detection OCT technique that utilizes a 2D detector array. This technique avoids mechanical scanning in imaging optics, thereby speeding up the imaging process and enhancing the quality of images. The current paper presents an FF-OCT instrument that is designed to be used in sphere measurement with the principle of multiple delays (MD) OCT to evaluate the curvature and radius of curved objects in single-shot imaging. The optimum combination of the MD principle with the FF-OCT method was evaluated, and the radius of a metal ball was measured with this method. The generated 2n-1 contour lines were obtained by using an MDE with n delays in a single en-face OCT image. This method of measurement, it engaged in the measurement accuracy of spherical and enriches the means of measurement, to make a spherical scan techniques flexible application.

  1. Functional imaging of small tissue volumes with diffuse optical tomography

    Science.gov (United States)

    Klose, Alexander D.; Hielscher, Andreas H.

    2006-03-01

    Imaging of dynamic changes in blood parameters, functional brain imaging, and tumor imaging are the most advanced application areas of diffuse optical tomography (DOT). When dealing with the image reconstruction problem one is faced with the fact that near-infrared photons, unlike X-rays, are highly scattered when they traverse biological tissue. Image reconstruction schemes are required that model the light propagation inside biological tissue and predict measurements on the tissue surface. By iteratively changing the tissue-parameters until the predictions agree with the real measurements, a spatial distribution of optical properties inside the tissue is found. The optical properties can be related to the tissue oxygenation, inflammation, or to the fluorophore concentration of a biochemical marker. If the model of light propagation is inaccurate, the reconstruction process will lead to an inaccurate result as well. Here, we focus on difficulties that are encountered when DOT is employed for functional imaging of small tissue volumes, for example, in cancer studies involving small animals, or human finger joints for early diagnosis of rheumatoid arthritis. Most of the currently employed image reconstruction methods rely on the diffusion theory that is an approximation to the equation of radiative transfer. But, in the cases of small tissue volumes and tissues that contain low scattering regions diffusion theory has been shown to be of limited applicability Therefore, we employ a light propagation model that is based on the equation of radiative transfer, which promises to overcome the limitations.

  2. Optical coherence tomography for embryonic imaging: a review

    Science.gov (United States)

    Raghunathan, Raksha; Singh, Manmohan; Dickinson, Mary E.; Larin, Kirill V.

    2016-05-01

    Embryogenesis is a highly complex and dynamic process, and its visualization is crucial for understanding basic physiological processes during development and for identifying and assessing possible defects, malformations, and diseases. While traditional imaging modalities, such as ultrasound biomicroscopy, micro-magnetic resonance imaging, and micro-computed tomography, have long been adapted for embryonic imaging, these techniques generally have limitations in their speed, spatial resolution, and contrast to capture processes such as cardiodynamics during embryogenesis. Optical coherence tomography (OCT) is a noninvasive imaging modality with micrometer-scale spatial resolution and imaging depth up to a few millimeters in tissue. OCT has bridged the gap between ultrahigh resolution imaging techniques with limited imaging depth like confocal microscopy and modalities, such as ultrasound sonography, which have deeper penetration but poorer spatial resolution. Moreover, the noninvasive nature of OCT has enabled live imaging of embryos without any external contrast agents. We review how OCT has been utilized to study developing embryos and also discuss advances in techniques used in conjunction with OCT to understand embryonic development.

  3. Digital balanced detection for fast optical computerized tomography

    Science.gov (United States)

    Hafiz, Rehan; Ozanyan, Krikor B.

    2006-10-01

    Analogue Balanced Photo-detection has found extensive usage in high- sensitivity small signal applications e.g. coherent heterodyne detection. It is particularly effective for laser intensity noise removal. Nevertheless, the high cost of the commercially available analogue systems makes them unsuitable for multi-channel applications, such as fast tomography. In this paper a flexible, scalable, inexpensive and compact solution for multi channel digital balanced detection is presented. The proposed system has two components: an analogue front-end, comprising a differential photodiode amplifier for minimizing the external interference noise, and a digital balanced noise remover. The latter component initially calculates a balancing factor (BF) from the average power ratio of the signal and reference photocurrents, measured with the object removed from the signal path. Three digital balancing algorithms (DBAx) are considered for subsequent processing. In DBA1, BF is directly used in real-time ratiometric calculations. In DBA2, the BF is adjusted in real time by monitoring the window-averaged power of the received photocurrents. In DBA3, first the baseline is removed using differentiation and then ratiometric detection is performed. Using the digital alternative only one measurement of the reference beam is necessary for single-source, multi-channel detection systems. The data from multiple channels are processed in parallel by pipelined hardware, configured as a state machine. The proposed system leads to a fast optical computerized tomography system using digital balanced detection.

  4. Multibeam fluorescence diffuse optical tomography using upconverting nanoparticles.

    Science.gov (United States)

    Liu, Haichun; Xu, Can T; Andersson-Engels, Stefan

    2010-03-01

    Fluorescence diffuse optical tomography (FDOT) is a biomedical imaging modality that can be used for localization and quantification of fluorescent molecules inside turbid media. In this ill-posed problem, the reconstruction quality is directly determined by the amount and quality of the information obtained from the boundary measurements. Regularly, more information can be obtained by increasing the number of excitation positions in an FDOT system. However, the maximum number of excitation positions is limited by the finite size of the excitation beam. In the present work, we demonstrate a method in FDOT to exploit the unique nonlinear power dependence of upconverting nanoparticles to further increase the amount of information in a raster-scanning setup by including excitation with two beams simultaneously. We show that the additional information can be used to obtain more accurate reconstructions.

  5. Study on cerebral microcirculation by Optical Doppler Tomography

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Optical Doppler Tomography (ODT) provides a novel method to measure the blood flow velocity in vessels with the diameter at micrometer scale. Rats with cranial window are used as a model, and the changes in the blood flow velocity of cerebral arterioles in sensory cortex are measured in real time with an established ODT system, under electrical stimulation and drug administration. The results show significant differences in the blood flow velocity between experimental groups and control groups, demonstrating the feasibility of ODT in the cerebral microcircula- tion study. Compared with the conventional Doppler ultrasound, ODT provides much higher spatial resolution, and thus holds a promising future in the application of the cerebral microcirculation study, especially in the observation of the blood flow velocity in micrometer scale vessels.

  6. Statistical analysis of motion contrast in optical coherence tomography angiography

    CERN Document Server

    Cheng, Yuxuan; Pan, Cong; Lu, Tongtong; Hong, Tianyu; Ding, Zhihua; Li, Peng

    2015-01-01

    Optical coherence tomography angiography (Angio-OCT), mainly based on the temporal dynamics of OCT scattering signals, has found a range of potential applications in clinical and scientific researches. In this work, based on the model of random phasor sums, temporal statistics of the complex-valued OCT signals are mathematically described. Statistical distributions of the amplitude differential (AD) and complex differential (CD) Angio-OCT signals are derived. The theories are validated through the flow phantom and live animal experiments. Using the model developed in this work, the origin of the motion contrast in Angio-OCT is mathematically explained, and the implications in the improvement of motion contrast are further discussed, including threshold determination and its residual classification error, averaging method, and scanning protocol. The proposed mathematical model of Angio-OCT signals can aid in the optimal design of the system and associated algorithms.

  7. Evaluation of microfluidic channels with optical coherence tomography

    KAUST Repository

    Czajkowski, J.

    2010-06-25

    Application of time domain, ultra high resolution optical coherence tomography (UHR-OCT) in evaluation of microfluidic channels is demonstrated. Presented study was done using experimental UHR-OCT device based on a Kerr-lens mode locked Ti:sapphire femtosecond laser, a photonic crystal fibre and modified, free-space Michelson interferometer. To show potential of the technique, microfluidic chip fabricated by VTT Center for Printed Intelligence (Oulu, Finland) was measured. Ability for full volumetric reconstruction in non-contact manner enabled complete characterization of closed entity of a microfluidic channel without contamination and harm for the sample. Measurement, occurring problems, and methods of postprocessing for raw data are described. Results present completely resolved physical structure of the channel, its spatial dimensions, draft angles and evaluation of lamination quality.

  8. Optical coherence tomography for vulnerability assessment of sandstone.

    Science.gov (United States)

    Bemand, Elizabeth; Liang, Haida

    2013-05-10

    Sandstone is an important cultural heritage material, in both architectural and natural settings, such as neolithic rock art panels. The majority of deterioration effects in porous materials such as sandstone are influenced by the presence and movement of water through the material. The presence of water within the porous network of a material results in changes in the optical coherence tomography signal intensity that can be used to monitor the wetting front of water penetration of dry porous materials at various depths. The technique is able to detect wetting front velocities from 1 cm s(-1) to 10(-6) cm s(-1), covering the full range of hydraulic conductivities likely to occur in natural sandstones from pervious to impervious.

  9. Indications of Optical Coherence Tomography in Keratoplasties: Literature Review

    Directory of Open Access Journals (Sweden)

    Thiago Trindade Nesi

    2012-01-01

    Full Text Available Optical coherence tomography (OCT of the anterior segment, in particular corneal OCT, has become a reliable tool for the cornea specialist, as it provides the acquisition of digital images at high resolution with a noncontact technology. In penetrating or lamellar keratoplasties, OCT can be used to assess central corneal thickness and pachymetry maps, as well as precise measurements of deep stromal opacities, thereby guiding the surgeon to choose the best treatment option. OCT has also been used to evaluate the keratoplasty postoperative period, for early identification of possible complications, such as secondary glaucoma or donor disc detachments in endothelial keratoplasties. Intraoperatively, OCT can be used to assess stromal bed regularity and transparency in anterior lamellar surgeries, especially for those techniques in which a bare Descemet’s membrane is the goal. The purpose of this paper is to review and discuss the role of OCT as a diagnostic tool in various types of keratoplasties.

  10. Microvascular contrast enhancement in optical coherence tomography using microbubbles

    Science.gov (United States)

    Assadi, Homa; Demidov, Valentin; Karshafian, Raffi; Douplik, Alexandre; Vitkin, I. Alex

    2016-07-01

    Gas microbubbles (MBs) are investigated as intravascular optical coherence tomography (OCT) contrast agents. Agar + intralipid scattering tissue phantoms with two embedded microtubes were fabricated to model vascular blood flow. One was filled with human blood, and the other with a mixture of human blood + MB. Swept-source structural and speckle variance (sv) OCT images, as well as speckle decorrelation times, were evaluated under both no-flow and varying flow conditions. Faster decorrelation times and higher structural and svOCT image contrasts were detected in the presence of MB in all experiments. The effects were largest in the svOCT imaging mode, and uniformly diminished with increasing flow velocity. These findings suggest the feasibility of utilizing MB for tissue hemodynamic investigations and for microvasculature contrast enhancement in OCT angiography.

  11. Optical Coherence Tomography and Raman Spectroscopy of the retina

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J W; Zawadzki, R J; Liu, R; Chan, J; Lane, S; Werner, J S

    2009-01-16

    Imaging the structure and correlating it with the biochemical content of the retina holds promise for fundamental research and for clinical applications. Optical coherence tomography (OCT) is commonly used to image the 3D structure of the retina and while the added functionality of biochemical analysis afforded by Raman scattering could provide critical molecular signatures for clinicians and researchers, there are many technical challenges to combining these imaging modalities. We present an ex vivo OCT microscope combined with Raman spectroscopy capable of collecting morphological and molecular information about a sample simultaneously. The combined instrument will be used to investigate remaining technical challenges to combine these imaging modalities, such as the laser power levels needed to achieve a Raman signal above the noise level without damaging the sample.

  12. Improving resolution of optical coherence tomography for imaging of microstructures

    Science.gov (United States)

    Shen, Kai; Lu, Hui; Wang, James H.; Wang, Michael R.

    2015-03-01

    Multi-frame superresolution technique has been used to improve the lateral resolution of spectral domain optical coherence tomography (SD-OCT) for imaging of 3D microstructures. By adjusting the voltages applied to ? and ? galvanometer scanners in the measurement arm, small lateral imaging positional shifts have been introduced among different C-scans. Utilizing the extracted ?-? plane en face image frames from these specially offset C-scan image sets at the same axial position, we have reconstructed the lateral high resolution image by the efficient multi-frame superresolution technique. To further improve the image quality, we applied the latest K-SVD and bilateral total variation denoising algorithms to the raw SD-OCT lateral images before and along with the superresolution processing, respectively. The performance of the SD-OCT of improved lateral resolution is demonstrated by 3D imaging a microstructure fabricated by photolithography and a double-layer microfluidic device.

  13. Epidermal segmentation in high-definition optical coherence tomography.

    Science.gov (United States)

    Li, Annan; Cheng, Jun; Yow, Ai Ping; Wall, Carolin; Wong, Damon Wing Kee; Tey, Hong Liang; Liu, Jiang

    2015-01-01

    Epidermis segmentation is a crucial step in many dermatological applications. Recently, high-definition optical coherence tomography (HD-OCT) has been developed and applied to imaging subsurface skin tissues. In this paper, a novel epidermis segmentation method using HD-OCT is proposed in which the epidermis is segmented by 3 steps: the weighted least square-based pre-processing, the graph-based skin surface detection and the local integral projection-based dermal-epidermal junction detection respectively. Using a dataset of five 3D volumes, we found that this method correlates well with the conventional method of manually marking out the epidermis. This method can therefore serve to effectively and rapidly delineate the epidermis for study and clinical management of skin diseases.

  14. Study on cerebral microcirculation by Optical Doppler Tomography

    Institute of Scientific and Technical Information of China (English)

    MENG Jie; DING ZhiHua; YANG Yong; GUO ZhouYi

    2008-01-01

    Optical Doppler Tomography (ODT) provides a novel method to measure the blood flow velocity in vessels with the diameter at micrometer scale.Rats with cranial window are used as a model,and the changes in the blood flow velocity of cerebral arterioles in sensory cortex are measured in real time with an established ODT system,under electrical stimulation and drug administration.The results show significant differences in the blood flow velocity between experimental groups and control groups,demonstrating the feasibility of ODT in the cerebral microcircula-tion study.Compared with the conventional Doppler ultrasound,ODT provides much higher spatial resolution,and thus holds a promising future in the application of the cerebral microcirculation study,especially in the observation of the blood flow velocity in micrometer scale vessels.

  15. Volumetric (3D) compressive sensing spectral domain optical coherence tomography.

    Science.gov (United States)

    Xu, Daguang; Huang, Yong; Kang, Jin U

    2014-11-01

    In this work, we proposed a novel three-dimensional compressive sensing (CS) approach for spectral domain optical coherence tomography (SD OCT) volumetric image acquisition and reconstruction. Instead of taking a spectral volume whose size is the same as that of the volumetric image, our method uses a sub set of the original spectral volume that is under-sampled in all three dimensions, which reduces the amount of spectral measurements to less than 20% of that required by the Shan-non/Nyquist theory. The 3D image is recovered from the under-sampled spectral data dimension-by-dimension using the proposed three-step CS reconstruction strategy. Experimental results show that our method can significantly reduce the sampling rate required for a volumetric SD OCT image while preserving the image quality.

  16. Spectralis optical coherence tomography findings in Welder′s maculopathy

    Directory of Open Access Journals (Sweden)

    Aniruddha Mahindrakar

    2013-01-01

    Full Text Available Welder′s maculopathy is a form of photochemical damage to the retina and is typically characterized by involvement of the outer retinal layers. Spectral domain optical coherence tomography (SD-OCT imaging was performed in three eyes of two patients with clinical findings suggestive of Welder′s maculopathy in occupational welders. A faceted foveal lesion characterized clinical examination and the SD-OCT line scans images showed a distinct discontinuity of the photoreceptor inner and outer segment (IS/OS junction. The external limiting membrane (ELM and the retinal pigment epithelial (RPE layer remained intact at the site of IS/OS defect. SD-OCT imaging offers a noninvasive way of evaluating the microstructural changes at the fovea in Welder′s maculopathy.

  17. Optical coherence tomography for imaging of skin and skin diseases

    DEFF Research Database (Denmark)

    Mogensen, Mette; Thrane, Lars; Jørgensen, Thomas Martini

    2009-01-01

    Optical coherence tomography (OCT) is an emerging imaging technology based on light reflection. It provides real-time images with up to 2-mm penetration into the skin and a resolution of approximately 10 μm. It is routinely used in ophthalmology. The normal skin and its appendages have been studied......, as have many diseases. The method can provide accurate measures of epidermal and nail changes in normal tissue. Skin cancer and other tumors, as well as inflammatory diseases, have been studied and good agreement found between OCT images and histopathological architecture. OCT also allows noninvasive...... monitoring of morphologic changes in skin diseases and may have a particular role in the monitoring of medical treatment of nonmelanoma skin cancer. The technology is however still evolving and continued technological development will necessitate an ongoing evaluation of its diagnostic accuracy. Several...

  18. Resonant Doppler imaging with Fourier domain optical coherence tomography

    Science.gov (United States)

    Leitgeb, Rainer A.; Szklumowska, Anna; Pircher, Michael; Gotzinger, Erich; Fercher, Adolf F.

    2005-04-01

    Fourier Domain Optical Coherene Tomography (FD OCT) is a high speed imaging modality with increased sensitivity as compared to standard time domain (TD) OCT. The higher sensitivity is especially important, if strongly scattering tissue such as blood is investigated. Recently it could be shown that retinal blood flow can be assessed in-vivo by high speed FD OCT. However the detection bandwidth of color Doppler (CD) FDOCT is strongly limited due to blurring of the detected interference fringes during exposure. This leads to a loss of sensitivity for detection of fast changes in tissue. Using a moving mirror as a reference one can effectively increase the detection bandwidth for CD FDOCT and perform perfusion sectioning. The modality is called resonant CD FDOCT imaging. The principle of the method is presented and experimentally verified.

  19. 4D embryonic cardiography using gated optical coherence tomography

    Science.gov (United States)

    Jenkins, M. W.; Rothenberg, F.; Roy, D.; Nikolski, V. P.; Hu, Z.; Watanabe, M.; Wilson, D. L.; Efimov, I. R.; Rollins, A. M.

    2006-01-01

    Simultaneous imaging of very early embryonic heart structure and function has technical limitations of spatial and temporal resolution. We have developed a gated technique using optical coherence tomography (OCT) that can rapidly image beating embryonic hearts in four-dimensions (4D), at high spatial resolution (10-15 μm), and with a depth penetration of 1.5 - 2.0 mm that is suitable for the study of early embryonic hearts. We acquired data from paced, excised, embryonic chicken and mouse hearts using gated sampling and employed image processing techniques to visualize the hearts in 4D and measure physiologic parameters such as cardiac volume, ejection fraction, and wall thickness. This technique is being developed to longitudinally investigate the physiology of intact embryonic hearts and events that lead to congenital heart defects.

  20. Sensing of Tooth Microleakage Based on Dental Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Chia-Wei Sun

    2015-01-01

    Full Text Available This study describes microleakage sensing based on swept-source optical coherence tomography (SS-OCT. With a handheld scanning probe, the SS-OCT system can provide portable real-time imaging for clinical diagnosis. Radiography is the traditional clinical imaging instrument used for dentistry; however, it does not provide good contrast images between filling material and the enamel of treated teeth with microleakage. The results of this study show that microleakage can be detected with oral probing using SS-OCT in vivo. The calculated microleakage length was 401 μm and the width is 148 μm, which is consistent with the related histological biopsy measurements. The diagnosis of microleakage in teeth could be useful for prevention of secondary caries in the clinical treatment plans developed in the field of oral medicine.

  1. Imaging port wine stains by fiber optical coherence tomography

    Science.gov (United States)

    Zhao, Shiyong; Gu, Ying; Xue, Ping; Guo, Jin; Shen, Tingmei; Wang, Tianshi; Huang, Naiyan; Zhang, Li; Qiu, Haixia; Yu, Xin; Wei, Xunbin

    2010-05-01

    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 blood vessels. We demonstrate that OCT may be a useful tool for the noninvasive imaging of PWS. It may help determine the photosensitizer dose and laser parameters in photodynamic therapy for treating port wine stains.

  2. Towards spectral-domain optical coherence tomography on a silicon chip

    NARCIS (Netherlands)

    Akca, B.I.; Wörhoff, K.; Nguyen, V.D.; Kalkman, J.; Leeuwen, van T.G.; Ridder, de R.M.; Pollnau, M.

    2011-01-01

    Optical coherence tomography (OCT) is a widely used optical imaging technology, particularly in the medical field, since it can provide non-invasive, sub-micrometer resolution diagnostic images of tissue. Current OCT systems contain optical fibers and free-space optical components which make these i

  3. Optical coherence tomography of the pulmonary arteries: A systematic review.

    Science.gov (United States)

    Jorge, Elisabete; Baptista, Rui; Calisto, João; Faria, Henrique; Monteiro, Pedro; Pan, Manuel; Pêgo, Mariano

    2016-01-01

    Optical coherence tomography (OCT) is an imaging technique extensively used for visualizing the coronary circulation, where it assists clinical decision-making. Along with the new interventional procedures being introduced for pulmonary vascular disease, there is an increasing need for intravascular imaging of the pulmonary arteries. Additionally, measurements of the wall thickness of the pulmonary arteries of patients with various types of pulmonary hypertension (PH) may provide relevant diagnostic and prognostic information. The aim of this review is to summarize all the available evidence on the use of OCT for imaging the pulmonary bed and to describe a simple protocol for OCT image acquisition. We conducted a systematic review of the literature using electronic reference databases through February 2015 (MEDLINE, Cochrane Library, Web of Knowledge, and references cited in other studies) and the search terms "optical coherence tomography," "pulmonary hypertension," and "pulmonary arteries." Studies in which OCT was used to image the pulmonary vessels were considered for inclusion. We identified 14 studies reporting OCT imaging data from the pulmonary arteries. OCT was able to identify intravascular thrombi in patients with chronic thromboembolic PH (CTEPH), and an increase in vessel wall thickness was found in most patients with PH, compared with the controls. OCT has also been reported to be useful for the selection of balloon size in the setting of balloon pulmonary angioplasty for CTEPH. The main limitations include lack of standardization, little data on outcomes, cost, and the technical limitations involved in visualizing small-diameter (arteries, and may provide additional information in the assessment of patients with PH. Prospective high-quality studies assessing the safety, validity, and clinical impact of OCT imaging for pulmonary vessels are warranted.

  4. Foveal thickness after phacoemulsification as measured by optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Gerasimos Th Georgopoulos

    2008-08-01

    Full Text Available Gerasimos Th Georgopoulos, Dimitrios Papaconstantinou, Maria Niskopoulou, Marilita Moschos, Ilias Georgalas, Chrysanthi KoutsandreaGlaucoma Department, Medical School, Athens University, Athens, GreeceBackground: Despite a significant body of research, no consistency on postoperative foveal thickness as measured by optical coherence tomography (OCT, can be recorded. The purpose of our study was to evaluate the effect of uncomplicated cataract surgery in the thickness of the retina in the foveal area during the early postoperative period.Methods: In a prospective study, 79 eyes were assessed by OCT, on day 1, and weeks 2 and 4 after uncomplicated phacoemulsification with intraocular lens implantation in the Athens University Clinic. The outcome measure was the thickness of the retina in the foveal area.Results: The thickness of the retina preoperatively is significantly smaller (150.4 ± 18.8 (p < 0.05 than the thickness of the retina on day 1 (171.8 ± 21 and week 2 (159.7 ± 19 and returned to the initial levels on week 4 (152 ± 17.1. The estimated correlation coefficients between preoperative and postoperative thickness of the retina were significant (p < 0.05. Conversely, no association was found between postoperative visual acuity and thickness of the retina, neither between the phacoemulsification energy and retinal thickness. Operation time, although inversely related with postoperative visual acuity, was not associated with the thickness of the retina.Conclusions: Following phacoemulsification, an increase in the foveal thickness was detected in the early postoperative period, quantified and followed up by OCT. The foveal thickness returned to the preoperative level, 1 month following surgery in our study. No association was shown between intraoperative parameters and increased postoperative retinal thickness.Keywords: optical coherence tomography, phacoemulsification, retinal thickness

  5. Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Muhammad Faizan Shirazi

    2016-09-01

    Full Text Available An application of spectral domain optical coherence tomography (SD-OCT was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast scanning, while a stable linear motorized translational stage was used for lateral (slow scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are difficult to observe using visual inspection methods. The rapid inspection enabled by this setup led to the early detection of product defects on the manufacturing line, resulting in a significant improvement in the quality assurance of industrial products.

  6. Fiber-optic polarization diversity detection for rotary probe optical coherence tomography.

    Science.gov (United States)

    Lee, Anthony M D; Pahlevaninezhad, Hamid; Yang, Victor X D; Lam, Stephen; MacAulay, Calum; Lane, Pierre

    2014-06-15

    We report a polarization diversity detection scheme for optical coherence tomography with a new, custom, miniaturized fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the X and Y OCT polarization channels prior to interference and the PM fiber outputs ensure defined X and Y axes after interference. Advantages for this scheme include easier alignment, lower cost, and easier miniaturization compared to designs with free-space bulk optical components. We demonstrate the utility of the detection system to mitigate the effects of rapidly changing polarization states when imaging with rotating fiber optic probes in Intralipid suspension and during in vivo imaging of human airways.

  7. Depth Compensated Spectral Domain Optical Coherence Tomography via Digital Compensation

    CERN Document Server

    Boroomand, Ameneh; Shafiee, Mohammad Javad; Bizheva, Kostadinka; Wong, Alexander

    2015-01-01

    Spectral Domain Optical Coherence Tomography (SD-OCT) is a well-known imaging modality which allows for \\textit{in-vivo} visualization of the morphology of different biological tissues at cellular level resolutions. The overall SD-OCT imaging quality in terms of axial resolution and Signal-to-Noise Ratio (SNR) degrades with imaging depth, while the lateral resolution degrades with distance from the focal plane. This image quality degradation is due both to the design of the SD-OCT imaging system and the optical properties of the imaged object. Here, we present a novel Depth Compensated SD-OCT (DC-OCT) system that integrates a Depth Compensating Digital Signal Processing (DC-DSP) module to improve the overall imaging quality via digital compensation. The designed DC-DSP module can be integrated to any SD-OCT system and is able to simultaneously compensate for the depth-dependent loss of axial and lateral resolutions, depth-varying SNR, as well as sidelobe artifact for improved imaging quality. The integrated D...

  8. Optical coherence tomography in guided surgery of GI cancer

    Science.gov (United States)

    Zagaynova, Elena V.; Abelevich, Alexander I.; Zagaynov, Vladimir E.; Gladkova, Natalia D.; Denisenko, Arkady N.; Feldchtein, Felix I.; Snopova, Ludmila B.; Kutis, Irina S.

    2005-04-01

    Optical Coherence Tomography (OCT) is a new high spatial resolution, real-time optical imaging modality, known from prior pilot studies for its high sensitivity to invasive cancer. We reported our results in an OCT feasibility study for accurate determination of the proximal border for esophageal carcinoma and the distal border for rectal carcinoma. The OCT study enrolled 19 patients with rectal adenocarcinoma and 24 patients with distal esophageal carcinoma (14 squamous cell carcinomas, 10 adenocarcinomas). During pre-surgery planning endoscopy we performed in vivo OCT imaging of the tumor border at four dial clock axes (12, 3, 6 and 9 o"clock). The OCT border then was marked by an electrocoagulator, or by a methylene blue tattoo. A cold biopsy (from the esophagus) was performed at visual and OCT borders and compared with visual and OCT readings. 27 post-surgery excised specimens were analyzed. OCT borders matched the histopathology in 94% cases in the rectum and 83.3% in the esophagus. In the cases of a mismatch between the OCT and histology borders, a deep tumor invasion occurred in the muscle layer (esophagus, rectum). Because of its high sensitivity to mucosal cancer, OCT can be used for pre-surgery planning and surgery guidance of the proximal border for esophageal carcinoma and the distal border for rectal carcinoma. However, deep invasion in the rectum or esophageal wall has to be controlled by alternative diagnostic modalities.

  9. Optical coherence tomography: imaging architect for dermal microdialysis in psoriasis

    Science.gov (United States)

    O'Connell, M.-L.; O'Connor, W.; Ramsay, B.; Guihen, E.; Ho, W. L.; Leahy, M. J.

    2011-03-01

    Optical coherence tomography (OCT) has been used as part of a ground breaking translational study to shed some light on one of the worlds most prevalent autoimmune diseases; psoriasis. The work successfully integrates the fields of optical imaging, biochemistry and dermatology in conducting a dermal microdialysis (DMD) trial for quantitative histamine assessment amongst a group of psoriasis sufferers. The DMD process involves temporary insertion of microscopic hollow tubes into a layer of skin to measure the levels of histamine and other important biological molecules in psoriasis. For comparison purposes, DMD catheters were implanted into healthy, peri-lesional and lesional skin regions. The catheters' entry and exit points and their precise locations in the epidermal layer of the skin were confirmed using OCT thus obtaining high resolution, wide-field images of the affected skin as well as catheter placement whilst local microdialysis enabled a tissue chemistry profile to be obtained from these three skin regions including histamine, a local immune system activator known to contribute towards itch and inflammation. Together these tools offer a synergistic approach in the clinical assessment of the disease. In addition, OCT delivered a non-invasive and rapid method for analyzing the affected skin architecture.

  10. Spectral domain optical coherence tomography morphology in optic disc pit associated maculopathy

    Directory of Open Access Journals (Sweden)

    Janusz Michalewski

    2014-01-01

    Full Text Available Purpose: Our purpose was to study the clinical manifestation and course of optic pit maculopathy using Spectral Domain Optical Coherence Tomography (SD- OCT images. Materials and Methods: We used SD-OCT to examine 20 eyes of 19 patients with a macular detachment in combination with an optic. Results: We observed five different fovea appearances in regard to fluid localization. In five eyes, we recorded changes in the fluid distribution with SD-OCT. In 17/20 eyes, we noted a communication between the perineural and subretinal and/or intraretinal space at the margin of the optic disc. Conclusion: 3-dimensional SD-OCT (3D-SDOCT scans revealed a three-fold connection, between subretinal and intraretinal space, perineural space, and the vitreous cavity. Therefore, we suppose that intraretinal or subretinal fluid in optic pit maculopathy may have both a vitreous and cerebrospinal origin. A membrane, covering the optic nerve was noted in 14 cases. Even if it seems intact in some B-scans, it is not complete in others several micrometers apart. Additionally, we observed fluid accumulation below the margin of the optic disc and hyperreflective porous tissue in the optic disc excavation. Those findings do not influence the course of maculopathy.

  11. Focusing optics of a parallel beam CCD optical tomography apparatus for 3D radiation gel dosimetry.

    Science.gov (United States)

    Krstajić, Nikola; Doran, Simon J

    2006-04-21

    Optical tomography of gel dosimeters is a promising and cost-effective avenue for quality control of radiotherapy treatments such as intensity-modulated radiotherapy (IMRT). Systems based on a laser coupled to a photodiode have so far shown the best results within the context of optical scanning of radiosensitive gels, but are very slow ( approximately 9 min per slice) and poorly suited to measurements that require many slices. Here, we describe a fast, three-dimensional (3D) optical computed tomography (optical-CT) apparatus, based on a broad, collimated beam, obtained from a high power LED and detected by a charged coupled detector (CCD). The main advantages of such a system are (i) an acquisition speed approximately two orders of magnitude higher than a laser-based system when 3D data are required, and (ii) a greater simplicity of design. This paper advances our previous work by introducing a new design of focusing optics, which take information from a suitably positioned focal plane and project an image onto the CCD. An analysis of the ray optics is presented, which explains the roles of telecentricity, focusing, acceptance angle and depth-of-field (DOF) in the formation of projections. A discussion of the approximation involved in measuring the line integrals required for filtered backprojection reconstruction is given. Experimental results demonstrate (i) the effect on projections of changing the position of the focal plane of the apparatus, (ii) how to measure the acceptance angle of the optics, and (iii) the ability of the new scanner to image both absorbing and scattering gel phantoms. The quality of reconstructed images is very promising and suggests that the new apparatus may be useful in a clinical setting for fast and accurate 3D dosimetry.

  12. Multimodal full-field optical coherence tomography on biological tissue: toward all optical digital pathology

    Science.gov (United States)

    Harms, F.; Dalimier, E.; Vermeulen, P.; Fragola, A.; Boccara, A. C.

    2012-03-01

    Optical Coherence Tomography (OCT) is an efficient technique for in-depth optical biopsy of biological tissues, relying on interferometric selection of ballistic photons. Full-Field Optical Coherence Tomography (FF-OCT) is an alternative approach to Fourier-domain OCT (spectral or swept-source), allowing parallel acquisition of en-face optical sections. Using medium numerical aperture objective, it is possible to reach an isotropic resolution of about 1x1x1 ìm. After stitching a grid of acquired images, FF-OCT gives access to the architecture of the tissue, for both macroscopic and microscopic structures, in a non-invasive process, which makes the technique particularly suitable for applications in pathology. Here we report a multimodal approach to FF-OCT, combining two Full-Field techniques for collecting a backscattered endogeneous OCT image and a fluorescence exogeneous image in parallel. Considering pathological diagnosis of cancer, visualization of cell nuclei is of paramount importance. OCT images, even for the highest resolution, usually fail to identify individual nuclei due to the nature of the optical contrast used. We have built a multimodal optical microscope based on the combination of FF-OCT and Structured Illumination Microscopy (SIM). We used x30 immersion objectives, with a numerical aperture of 1.05, allowing for sub-micron transverse resolution. Fluorescent staining of nuclei was obtained using specific fluorescent dyes such as acridine orange. We present multimodal images of healthy and pathological skin tissue at various scales. This instrumental development paves the way for improvements of standard pathology procedures, as a faster, non sacrificial, operator independent digital optical method compared to frozen sections.

  13. Analysis of dental abfractions by optical coherence tomography

    Science.gov (United States)

    Demjan, Enikö; Mărcăuţeanu, Corina; Bratu, Dorin; Sinescu, Cosmin; Negruţiu, Meda; Ionita, Ciprian; Topală, Florin; Hughes, Michael; Bradu, Adrian; Dobre, George; Podoleanu, Adrian Gh.

    2010-02-01

    Aim and objectives. Abfraction is the pathological loss of cervical hard tooth substance caused by biomechanical overload. High horizontal occlusal forces result in large stress concentrations in the cervical region of the teeth. These stresses may be high enough to cause microfractures in the dental hard tissues, eventually resulting in the loss of cervical enamel and dentin. The present study proposes the microstructural characterization of these cervical lesions by en face optical coherence tomography (eFOCT). Material and methods: 31 extracted bicuspids were investigated using eFOCT. 24 teeth derived from patients with active bruxism and occlusal interferences; they presented deep buccal abfractions and variable degrees of occlusal pathological attrition. The other 7 bicuspids were not exposed to occlusal overload and had a normal morphology of the dental crowns. The dental samples were investigated using an eFOCT system operating at 1300 nm (B-scan at 1 Hz and C-scan mode at 2 Hz). The system has a lateral resolution better than 5 μm and a depth resolution of 9 μm in tissue. OCT images were further compared with micro - computer tomography images. Results. The eFOCT investigation of bicuspids with a normal morphology revealed a homogeneous structure of the buccal cervical enamel. The C-scan and B-scan images obtained from the occlusal overloaded bicuspids visualized the wedge-shaped loss of cervical enamel and damage in the microstructure of the underlaying dentin. The high occlusal forces produced a characteristic pattern of large cracks, which reached the tooth surface. Conclusions: eFOCT is a promising imaging method for dental abfractions and it may offer some insight on the etiological mechanism of these noncarious cervical lesions.

  14. Donor disc attachment assessment with intraoperative spectral optical coherence tomography during descemet stripping automated endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Edward Wylegala

    2013-01-01

    Full Text Available Optical coherence tomography has already been proven to be useful for pre- and post-surgical anterior eye segment assessment, especially in lamellar keratoplasty procedures. There is no evidence for intraoperative usefulness of optical coherence tomography (OCT. We present a case report of the intraoperative donor disc attachment assessment with spectral-domain optical coherence tomography in case of Descemet stripping automated endothelial keratoplasty (DSAEK surgery combined with corneal incisions. The effectiveness of the performed corneal stab incisions was visualized directly by OCT scan analysis. OCT assisted DSAEK allows the assessment of the accuracy of the Descemet stripping and donor disc attachment.

  15. Classifying murine glomerulonephritis using optical coherence tomography and optical coherence elastography.

    Science.gov (United States)

    Liu, Chih-Hao; Du, Yong; Singh, Manmohan; Wu, Chen; Han, Zhaolong; Li, Jiasong; Chang, Anthony; Mohan, Chandra; Larin, Kirill V

    2016-08-01

    Acute glomerulonephritis caused by antiglomerular basement membrane marked by high mortality. The primary reason for this is delayed diagnosis via blood examination, urine analysis, tissue biopsy, or ultrasound and X-ray computed tomography imaging. Blood, urine, and tissue-based diagnoses can be time consuming, while ultrasound and CT imaging have relatively low spatial resolution, with reduced sensitivity. Optical coherence tomography is a noninvasive and high-resolution imaging technique that provides superior spatial resolution (micrometer scale) as compared to ultrasound and CT. Changes in tissue properties can be detected based on the optical metrics analyzed from the OCT signals, such as optical attenuation and speckle variance. Furthermore, OCT does not rely on ionizing radiation as with CT imaging. In addition to structural changes, the elasticity of the kidney can significantly change due to nephritis. In this work, OCT has been utilized to quantify the difference in tissue properties between healthy and nephritic murine kidneys. Although OCT imaging could identify the diseased tissue, its classification accuracy is clinically inadequate. By combining optical metrics with elasticity, the classification accuracy improves from 76% to 95%. These results show that OCT combined with OCE can be a powerful tool for identifying and classifying nephritis. Therefore, the OCT/OCE method could potentially be used as a minimally invasive tool for longitudinal studies during the progression and therapy of glomerulonephritis as well as complement and, perhaps, substitute highly invasive tissue biopsies. Elastic-wave propagation in mouse healthy and nephritic kidneys.

  16. Ex vivo imaging of human thyroid pathology using integrated optical coherence tomography and optical coherence microscopy

    Science.gov (United States)

    Zhou, Chao; Wang, Yihong; Aguirre, Aaron D.; Tsai, Tsung-Han; Cohen, David W.; Connolly, James L.; Fujimoto, James G.

    2010-01-01

    We evaluate the feasibility of optical coherence tomography (OCT) and optical coherence microscopy (OCM) for imaging of benign and malignant thyroid lesions ex vivo using intrinsic optical contrast. 34 thyroid gland specimens are imaged from 17 patients, covering a spectrum of pathology ranging from normal thyroid to benign disease/neoplasms (multinodular colloid goiter, Hashimoto's thyroiditis, and follicular adenoma) and malignant thyroid tumors (papillary carcinoma and medullary carcinoma). Imaging is performed using an integrated OCT and OCM system, with tumor cells, can be identified from OCT and OCM images and are clearly differentiable from normal or benign thyroid tissues. With further development of needle-based imaging probes, OCT and OCM could be promising techniques to use for the screening of thyroid nodules and to improve the diagnostic specificity of fine needle aspiration evaluation.

  17. Profile and Determinants of Retinal Optical Intensity in Normal Eyes with Spectral Domain Optical Coherence Tomography.

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    Binyao Chen

    Full Text Available To investigate the profile and determinants of retinal optical intensity in normal subjects using 3D spectral domain optical coherence tomography (SD OCT.A total of 231 eyes from 231 healthy subjects ranging in age from 18 to 80 years were included and underwent a 3D OCT scan. Forty-four eyes were randomly chosen to be scanned by two operators for reproducibility analysis. Distribution of optical intensity of each layer and regions specified by the Early Treatment of Diabetic Retinopathy Study (ETDRS were investigated by analyzing the OCT raw data with our automatic graph-based algorithm. Univariate and multivariate analyses were performed between retinal optical intensity and sex, age, height, weight, spherical equivalent (SE, axial length, image quality, disc area and rim/disc area ratio (R/D area ratio.For optical intensity measurements, the intraclass correlation coefficient of each layer ranged from 0.815 to 0.941, indicating good reproducibility. Optical intensity was lowest in the central area of retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and photoreceptor layer, except for the retinal pigment epithelium (RPE. Optical intensity was positively correlated with image quality in all retinal layers (0.5530.05. There was no relationship between retinal optical intensity and sex, height, weight, SE, axial length, disc area and R/D area ratio.There was a specific pattern of distribution of retinal optical intensity in different regions. The optical intensity was affected by image quality and age. Image quality can be used as a reference for normalization. The effect of age needs to be taken into consideration when using OCT for diagnosis.

  18. Region-of-interest diffuse optical tomography system

    Science.gov (United States)

    Saikia, Manob Jyoti; Kanhirodan, Rajan

    2016-01-01

    Diffuse optical tomography (DOT) using near-infrared light is a promising tool for non-invasive imaging of deep tissue. This technique is capable of quantitative reconstruction of absorption (μa) and scattering coefficient (μs) inhomogeneities in the tissue. The rationale for reconstructing the optical property map is that the absorption coefficient variation provides diagnostic information about metabolic and disease states of the tissue. The aim of DOT is to reconstruct the internal tissue cross section with good spatial resolution and contrast from noisy measurements non-invasively. We develop a region-of-interest scanning system based on DOT principles. Modulated light is injected into the phantom/tissue through one of the four light emitting diode sources. The light traversing through the tissue gets partially absorbed and scattered multiple times. The intensity and phase of the exiting light are measured using a set of photodetectors. The light transport through a tissue is diffusive in nature and is modeled using radiative transfer equation. However, a simplified model based on diffusion equation (DE) can be used if the system satisfies following conditions: (a) the optical parameter of the inhomogeneity is close to the optical property of the background, and (b) μs of the medium is much greater than μa (μs > > μa). The light transport through a highly scattering tissue satisfies both of these conditions. A discrete version of DE based on finite element method is used for solving the inverse problem. The depth of probing light inside the tissue depends on the wavelength of light, absorption, and scattering coefficients of the medium and the separation between the source and detector locations. Extensive simulation studies have been carried out and the results are validated using two sets of experimental measurements. The utility of the system can be further improved by using multiple wavelength light sources. In such a scheme, the spectroscopic

  19. Region-of-interest diffuse optical tomography system

    Energy Technology Data Exchange (ETDEWEB)

    Saikia, Manob Jyoti; Kanhirodan, Rajan, E-mail: rajan@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2016-01-15

    Diffuse optical tomography (DOT) using near-infrared light is a promising tool for non-invasive imaging of deep tissue. This technique is capable of quantitative reconstruction of absorption (μ{sub a}) and scattering coefficient (μ{sub s}) inhomogeneities in the tissue. The rationale for reconstructing the optical property map is that the absorption coefficient variation provides diagnostic information about metabolic and disease states of the tissue. The aim of DOT is to reconstruct the internal tissue cross section with good spatial resolution and contrast from noisy measurements non-invasively. We develop a region-of-interest scanning system based on DOT principles. Modulated light is injected into the phantom/tissue through one of the four light emitting diode sources. The light traversing through the tissue gets partially absorbed and scattered multiple times. The intensity and phase of the exiting light are measured using a set of photodetectors. The light transport through a tissue is diffusive in nature and is modeled using radiative transfer equation. However, a simplified model based on diffusion equation (DE) can be used if the system satisfies following conditions: (a) the optical parameter of the inhomogeneity is close to the optical property of the background, and (b) μ{sub s} of the medium is much greater than μ{sub a} (μ{sub s} > > μ{sub a}). The light transport through a highly scattering tissue satisfies both of these conditions. A discrete version of DE based on finite element method is used for solving the inverse problem. The depth of probing light inside the tissue depends on the wavelength of light, absorption, and scattering coefficients of the medium and the separation between the source and detector locations. Extensive simulation studies have been carried out and the results are validated using two sets of experimental measurements. The utility of the system can be further improved by using multiple wavelength light sources. In such

  20. The use of optical coherence tomography in maxillofacial surgery

    Science.gov (United States)

    Al-Obaidi, Mohammed; Tandon, Rahul; Tiwana, Paul

    2015-02-01

    The ever-evolving medical field continues to trend toward less invasive approaches to the diagnosis and treatment of pathological conditions. Basic sciences research has allowed for improved technologies that are translated to the clinical sciences. Similarly, advancements in imaging modalities continue to improve and their applications become more varied. As such, surgeons and pathologists are able to depend on smaller samples for tissue diagnosis of pathological disease, where once large sections of tissue were needed. Optical coherence tomography (OCT), a high-resolution imaging technique, has been used extensively in different medical fields to improve diagnostic yield. Its use in dental fields, particularly in oral and maxillofacial surgery, remains limited. Our goal is to assess the use of OCT for improving soft tissue analysis and diagnosis, particularly for its applications in the field of oral and maxillofacial surgery. Optical coherence tomography is a modality that uses an optical signal using safe near-infrared light which is reflected off the sub-surface structures. This allows for high-resolution cross-sectional images of the tissue morphology to be obtained. Ophthalmologists have been using OCT to obtain images of the retina to assess for age-related macular degeneration. More recently, OCT has been used by Interventional Cardiology to image coronary arteries, and assess plaque thickness and morphology. This technology is now being investigated in several medical fields as a form of optical biopsy, providing in situ images with high-resolution morphology of tissues. We are particularly interested in its use on epithelial tissues, and therefore performed a literature review on the use of OCT for assessing epithelium. Evaluation of histologically-diagnosed actinic keratosis, for example, was found to correlate well with the imaging discrepancies found on OCT; and the in vivo assessment of atypical keratinocytes was firmly established. Additionally

  1. Integral ceramic superstructure evaluation using time domain optical coherence tomography

    Science.gov (United States)

    Sinescu, Cosmin; Bradu, Adrian; Topala, Florin I.; Negrutiu, Meda Lavinia; Duma, Virgil-Florin; Podoleanu, Adrian G.

    2014-02-01

    Optical Coherence Tomography (OCT) is a non-invasive low coherence interferometry technique that includes several technologies (and the corresponding devices and components), such as illumination and detection, interferometry, scanning, adaptive optics, microscopy and endoscopy. From its large area of applications, we consider in this paper a critical aspect in dentistry - to be investigated with a Time Domain (TD) OCT system. The clinical situation of an edentulous mandible is considered; it can be solved by inserting 2 to 6 implants. On these implants a mesostructure will be manufactured and on it a superstructure is needed. This superstructure can be integral ceramic; in this case materials defects could be trapped inside the ceramic layers and those defects could lead to fractures of the entire superstructure. In this paper we demonstrate that a TD-OCT imaging system has the potential to properly evaluate the presence of the defects inside the ceramic layers and those defects can be fixed before inserting the prosthesis inside the oral cavity. Three integral ceramic superstructures were developed by using a CAD/CAM technology. After the milling, the ceramic layers were applied on the core. All the three samples were evaluated by a TD-OCT system working at 1300 nm. For two of the superstructures evaluated, no defects were found in the most stressed areas. The third superstructure presented four ceramic defects in the mentioned areas. Because of those defects the superstructure may fracture. The integral ceramic prosthesis was send back to the dental laboratory to fix the problems related to the material defects found. Thus, TD-OCT proved to be a valuable method for diagnosing the ceramic defects inside the integral ceramic superstructures in order to prevent fractures at this level.

  2. Technical Note: Wet validation of optical tomography for drinking water discolouration studies

    Directory of Open Access Journals (Sweden)

    R. Floris

    2013-02-01

    Full Text Available This paper presents a set of validation experiments for the reconstruction of a cross-sectional particle concentration field in a transparent pipe filled with a fluid using optical tomography.

  3. Technical Note: Wet validation of optical tomography for drinking water discolouration studies

    Directory of Open Access Journals (Sweden)

    R. Floris

    2013-06-01

    Full Text Available This paper presents a set of validation experiments for the reconstruction of a cross-sectional particle concentration field in a transparent pipe filled with a fluid using optical tomography.

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

    Science.gov (United States)

    Yin, Biwei; Dwelle, Jordan; Wang, Bingqing; Wang, Tianyi; Feldman, Marc D; Rylander, Henry G; Milner, Thomas E

    2015-11-01

    Optical coherence tomography (OCT) is an imaging technique that constructs a depth-resolved image by measuring the optical path-length difference between broadband light backscattered from a sample and a reference surface. For many OCT sample arm optical configurations, sample illumination and backscattered light detection share a common path. When a phase mask is placed in the sample path, features in the detected signal are observed, which suggests that an analysis of a generic common path OCT imaging system is warranted. In this study, we present a Fourier optics analysis using a Fresnel diffraction approximation of an OCT system with a path-length-multiplexing element (PME) inserted in the sample arm optics. The analysis may be generalized for most phase-mask-based OCT systems. A radial-angle-diverse PME is analyzed in detail, and the point spread function, coherent transfer function, sensitivity of backscattering angular diversity detection, and signal formation in terms of sample spatial frequency are simulated and discussed. The analysis reveals important imaging features and application limitations of OCT imaging systems with a phase mask in the sample path optics.

  5. Effects of haemodilution on the optical properties of blood during coagulation studied by optical coherence tomography

    Science.gov (United States)

    Liu, B.; Liu, Y.; Wei, H.; Yang, X.; Wu, G.; Guo, Z.; Yang, H.; He, Y.; Xie, S.

    2016-11-01

    We report an investigation of the effects of blood dilution with hypertonic (7.5 %) and normal (0.9 %) saline on its optical properties during coagulation in vitro using optical coherence tomography. The light penetration depth and attenuation coefficient are obtained from the dependences of reflectance on the depth. Normal whole blood has served as the control group. The average coagulation time is equal to 420 +/- 16, 418 +/- 16 and 358 +/- 14 {\\text{s}} with blood volume replacement of 2 %, 11 %, and 20 % by 0.9 % normal saline, respectively. With 2 %, 11% and 20% blood volume replacement with 7.5 % hypertonic saline, the average coagulation time is 422 +/- 17, 1160 +/- 45 and 1730 +/- 69 {\\text{s}}, respectively. For normal whole blood, the average coagulation time amounts to 425 +/- 19 {\\text{s}}. it is shown that dilution with normal saline has a procoagulant effect when it replaces 20 % of blood volume, and hypertonic saline has an anticoagulant effect if it replaces 11 % or more of blood volume. It is concluded that optical coherence tomography is a potential technique to quantify and monitor the liquid - gel transition during the coagulation process of blood diluted by normal and hypertonic saline.

  6. Surface imaging of metallic material fractures using optical coherence tomography.

    Science.gov (United States)

    Hutiu, Gheorghe; Duma, Virgil-Florin; Demian, Dorin; Bradu, Adrian; Podoleanu, Adrian Gh

    2014-09-10

    We demonstrate the capability of optical coherence tomography (OCT) to perform topography of metallic surfaces after being subjected to ductile or brittle fracturing. Two steel samples, OL 37 and OL 52, and an antifriction Sn-Sb-Cu alloy were analyzed. Using an in-house-built swept source OCT system, height profiles were generated for the surfaces of the two samples. Based on such profiles, it can be concluded that the first two samples were subjected to ductile fracture, while the third one was subjected to brittle fracture. The OCT potential for assessing the surface state of materials after fracture was evaluated by comparing OCT images with images generated using an established method for such investigations, scanning electron microscopy (SEM). Analysis of cause of fracture is essential in response to damage of machinery parts during various accidents. Currently the analysis is performed using SEM, on samples removed from the metallic parts, while OCT would allow in situ imaging using mobile units. To the best of our knowledge, this is the first time that the OCT capability to replace SEM has been demonstrated. SEM is a more costly and time-consuming method to use in the investigation of surfaces of microstructures of metallic materials.

  7. Imaging Cutaneous T-Cell Lymphoma with Optical Coherence Tomography

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    Hans Christian Ring

    2012-07-01

    Full Text Available Aim: To investigate the presentation of a patch-stage cutaneous T-cell lymphoma (CTCL using optical coherence tomography (OCT. Methods: A patient with a patch caused by CTCL was photographed digitally, OCT-scanned and biopsied. A normal skin area adjacent to the patch was OCT-scanned for comparison, but not biopsied. The OCT image and the histological image were compared. Results: The OCT images illustrated a thickened and hyperreflective stratum corneum. OCT also demonstrated several elongated hyporeflective structures in the dermis. The largest structure was measured to have a width of 0.13 mm. A good immediate correlation was found between histology and OCT imaging of the sample. Conclusion: The aetiology of the elongated structures is thought to be lymphomatous infiltrates. Similar findings have been described in ocular lymphoma and may therefore be an important characteristic of cutaneous lymphoma. It may further be speculated that the differences in OCT images may reflect the biological behaviour of the infiltrate. This observation therefore suggests that OCT imaging may be a relevant tool for the in vivo investigation of mycosis fungoides and other CTCLs, but in order to verify these observed patterns in OCT imaging, further investigations will be required.

  8. Optical coherence tomography for the diagnosis of human otitis media

    Science.gov (United States)

    Cho, Nam Hyun; Jung, Unsang; Jang, Jeong Hun; Jung, Woonggyu; Kim, Jeehyun; Lee, Sang Heun; Boppart, Stephen A.

    2013-05-01

    We report the application of Optical Coherence Tomography (OCT) to various types of human cases of otitis media (OM). Whereas conventional diagnostic modalities for OM, including standard and pneumatic otoscopy, are limited to visualizing the surface information of the tympanic membrane (TM), OCT is able to effectively reveal the depth-resolved microstructural below the TM with a very high spatial resolution. With the potential advantage of using OCT for diagnosing different types of OM, we examined in-vivo the use of 840 nm wavelength, and OCT spectral domain OCT (SDOCT) techniques, in several human cases including normal ears, and ears with adhesive and effusion types of OM. Peculiar positions were identified in two-dimensional OCT images of abnormal TMs compared to images of a normal TM. Analysis of A-scan (axial depth-scans) data from these positions could successfully identify unique patterns for different constituents within effusions. These OCT images may not only be used for constructing a database for the diagnosis and classification of OM, but they may also demonstrate the feasibility and advantages for upgrading the current otoscopy techniques.

  9. Retinal Imaging of Infants on Spectral Domain Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Anand Vinekar

    2015-01-01

    Full Text Available Spectral domain coherence tomography (SD OCT has become an important tool in the management of pediatric retinal diseases. It is a noncontact imaging device that provides detailed assessment of the microanatomy and pathology of the infant retina with a short acquisition time allowing office examination without the requirement of anesthesia. Our understanding of the development and maturation of the infant fovea has been enhanced by SD OCT allowing an in vivo assessment that correlates with histopathology. This has helped us understand the critical correlation of foveal development with visual potential in the first year of life and beyond. In this review, we summarize the recent literature on the clinical applications of SD OCT in studying the pathoanatomy of the infant macula, its ability to detect subclinical features, and its correlation with disease and vision. Retinopathy of prematurity and macular edema have been discussed in detail. The review also summarizes the current status of SD OCT in other infant retinal conditions, imaging the optic nerve, the choroid, and the retinal nerve fibre in infants and children, and suggests future areas of research.

  10. Benefits of optical coherence tomography for imaging of skin diseases

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    Utz S.R.

    2015-09-01

    Full Text Available Aim: working out the methods of visualization of information obtained during optical coherent tomography in normal skin and in series of inflammatory disorders. Materials and Methods. OCS1300SS (made in Thorlabs, USA was used in which the source of emission of radiation was a super-luminiscent diode with mean wavelength of 1325 nm. 12 patients with different skin conditions and 5 virtually healthy volunteers were examined with ОСТ procedure in OPD and IPD settings. High resolution USG numerical system DUB (TPM GmbH, Germany was used for comparative USG assessment. Results. ОСТ demonstrated considerably more detailed picture of the objects scanned compared to USG investigation. Image obtained with the help of ОСТ contains vital information about sizes of macro-morphological elements, status of vascular elements and their density in different depths of the skin. Conclusion. Additional results obtained from ОСТ of the skin lesions in plane section improves attraction for ОСТ in practical dermatology.

  11. Thrombosis and morphology of plaque rupture using optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    GUO Jun; CHEN Yun-dai; TIAN Feng; LIU Hong-bin; CHEN Lian; SUN Zhi-jun; REN Yi-hong

    2013-01-01

    Background Thrombosis following plaque rupture is the main cause of acute coronary syndrome,but not all plaque ruptures lead to thrombosis.There are limited in vivo data on the relationship between the morphology of ruptured plaque and thrombosis.Methods We used optical coherence tomography (OCT) to investigate the morphology of plaque rupture and its relation to coronary artery thrombosis in patients with coronary heart disease.Forty-two patients with coronary artery plaque rupture detected by OCT were divided into two groups (with or without thrombus) and the morphological characteristics of ruptured plaque,including fibrous cap thickness and broken cap site,were recorded.Results The fibrous cap of ruptured plaque with thrombus was significantly thinner compared to caps without thrombus ((57.00±17.00) μm vs.(96.00±48.00) μm; P=0.0076).Conclusions Plaque rupture associated with thrombosis occurs primarily in plaque covered by a thin fibrous cap.Thick fibrous caps are associated with greater stability of ruptured plaque.

  12. Clinical use of optical coherence tomography and fractional flow reserve

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    Ivanović Vladimir

    2016-01-01

    Full Text Available Introduction. The aim of each diagnostic method is to serve as a guide in deciding about the right patient treatment. During myocardial revascularization the decision to perform revascularization is usually not easy to make, especially in case of borderline stenosis. It has been proven that it is not enough to base morphological evaluation of coronary artery vessel stenosis solely on angiography. It is necessary to include additional modern diagnostic methods for functional analysis and detailed morphological analysis using fractional flow reserve (FFR and optical coherence tomography (OCT, respectively. Case reports. In the first case report we showed the significance of morphological analysis using OCT and proved that it was not lumen stenosis. The second and the third case reports showed the complementarity between functional analysis (FFR and morphological analysis (OCT of stenosis in solving a complex coronary disease. The fourth case report showed the significance of OCT in dealing with the recurrent stent restenosis. Conclusion. By these short case reports we confirmed that percutaneous coronary intervention (PCI guided by angiography is definitely not enough in deciding about myocardial revascularization especially in patients with a complex coronary disease. In certain cases FFR and OCT procedures can be complementary methods and improve quality of revascularization, particularly in the case of recurrent in-stent restenosis.

  13. Micro-optical coherence tomography of the mammalian cochlea

    Science.gov (United States)

    Iyer, Janani S.; Batts, Shelley A.; Chu, Kengyeh K.; Sahin, Mehmet I.; Leung, Hui Min; Tearney, Guillermo J.; Stankovic, Konstantina M.

    2016-01-01

    The mammalian cochlea has historically resisted attempts at high-resolution, non-invasive imaging due to its small size, complex three-dimensional structure, and embedded location within the temporal bone. As a result, little is known about the relationship between an individual’s cochlear pathology and hearing function, and otologists must rely on physiological testing and imaging methods that offer limited resolution to obtain information about the inner ear prior to performing surgery. Micro-optical coherence tomography (μOCT) is a non-invasive, low-coherence interferometric imaging technique capable of resolving cellular-level anatomic structures. To determine whether μOCT is capable of resolving mammalian intracochlear anatomy, fixed guinea pig inner ears were imaged as whole temporal bones with cochlea in situ. Anatomical structures such as the tunnel of Corti, space of Nuel, modiolus, scalae, and cell groupings were visualized, in addition to individual cell types such as neuronal fibers, hair cells, and supporting cells. Visualization of these structures, via volumetrically-reconstructed image stacks and endoscopic perspective videos, represents an improvement over previous efforts using conventional OCT. These are the first μOCT images of mammalian cochlear anatomy, and they demonstrate μOCT’s potential utility as an imaging tool in otology research. PMID:27633610

  14. Optical coherence tomography-guided classification of epiretinal membranes.

    Science.gov (United States)

    Konidaris, Vasileios; Androudi, Sofia; Alexandridis, Alexandros; Dastiridou, Anna; Brazitikos, Periklis

    2015-08-01

    To study and classify epiretinal membranes (ERMs) based on spectral domain optical coherence tomography (SD-OCT) findings. One hundred and twelve patients with ERMs were examined clinically and underwent OCT examination. The anatomical structure of the macula and vitreoretinal interface was studied. ERMs were classified in two categories: A, with posterior vitreous detachment (PVD) (91 cases), and B, with the absence of PVD (21 cases). Category A was divided into two subcategories: A1, without contraction of the ERM (37 cases), and A2, with the presence of membrane contraction (54 cases). A2 was further subdivided into A2.1, with retinal folding (15 cases), A2.2, with edema (23 cases), A2.3, with cystoid macular edema (9 cases), and A2.4, with lamellar macular hole (7 cases). Category B was divided in two subcategories: B1, without vitreomacular traction (VMT) (4 cases), and B2, with the presence of VMT (17 cases). Category B2 was subdivided into B2.1, with edema (9 cases), B2.2, presenting retinal detachment (5 cases), and B2.3, with schisis (3 cases). OCT classification of ERMs provides useful information on the anatomical structure of the retina, and the accurate estimation of vitreoretinal interface.

  15. Polarization sensitive spectroscopic optical coherence tomography for multimodal imaging

    Science.gov (United States)

    Strąkowski, Marcin R.; Kraszewski, Maciej; Strąkowska, Paulina; Trojanowski, Michał

    2015-03-01

    Optical coherence tomography (OCT) is a non-invasive method for 3D and cross-sectional imaging of biological and non-biological objects. The OCT measurements are provided in non-contact and absolutely safe way for the tested sample. Nowadays, the OCT is widely applied in medical diagnosis especially in ophthalmology, as well as dermatology, oncology and many more. Despite of great progress in OCT measurements there are still a vast number of issues like tissue recognition or imaging contrast enhancement that have not been solved yet. Here we are going to present the polarization sensitive spectroscopic OCT system (PS-SOCT). The PS-SOCT combines the polarization sensitive analysis with time-frequency analysis. Unlike standard polarization sensitive OCT the PS-SOCT delivers spectral information about measured quantities e.g. tested object birefringence changes over the light spectra. This solution overcomes the limits of polarization sensitive analysis applied in standard PS-OCT. Based on spectral data obtained from PS-SOCT the exact value of birefringence can be calculated even for the objects that provide higher order of retardation. In this contribution the benefits of using the combination of time-frequency and polarization sensitive analysis are being expressed. Moreover, the PS-SOCT system features, as well as OCT measurement examples are presented.

  16. Spectral domain optical coherence tomography with dual-balanced detection

    Science.gov (United States)

    Bo, En; Liu, Xinyu; Chen, Si; Luo, Yuemei; Wang, Nanshuo; Wang, Xianghong; Liu, Linbo

    2016-03-01

    We developed a spectral domain optical coherence tomography (SD-OCT) system employing dual-balanced detection (DBD) for direct current term suppression and SNR enhancement, especially for auto-autocorrelation artifacts reduction. The DBD was achieved by using a beam splitter to building a free-space Michelson interferometer, which generated two interferometric spectra with a phase difference of π. These two phase-opposed spectra were guided to the spectrometer through two single mode fibers of the 8 fiber v-groove array and acquired by ultizing the upper two lines of a three-line CCD camera. We rotated this fiber v-groove array by 1.35 degrees to focus two spectra onto the first and second line of the CCD camera. Two spectra were aligned by optimum spectrum matching algorithm. By subtracting one spectrum from the other, this dual-balanced detection system achieved a direct current term suppression of ~30 dB, SNR enhancement of ~3 dB, and auto-autocorrelation artifacts reduction of ~10 dB experimentally. Finally we respectively validated the feasibility and performance of dual-balanced detection by imaging a glass plate and swine corneal tissue ex vivo. The quality of images obtained using dual-balanced detection was significantly improved with regard to the conventional single-detection (SD) images.

  17. Optical Coherence Tomography: Clinical Applications in Medical Practice

    Directory of Open Access Journals (Sweden)

    Abdullah Al-Mujaini

    2013-03-01

    Full Text Available Optical Coherence Tomography (OCT is a success story of scientific and technological co-operation between a physicist and a clinician. The concept of cross-sectional imaging revolutionalized the applicability of OCT in the medical profession. OCT is a non-contact, topographic, biomicroscopic device that provides high resolution, cross-sectional digital images of live biological tissues in vivo and in real time. OCT is based on the property of tissues to reflect and backscatter light involving low-coherence interferometry. The spatial resolution of as little as 3 microns or even less has allowed us to study tissues almost at a cellular level. Overall, OCT is an invaluable adjunct in the diagnosis and follow up of many diseases of both anterior and posterior segments of the eye, primarily or secondary to systemic diseases. The digitalization and advanced software has made it possible to store and retrieve huge patient data for patient services, clinical applications and academic research. OCT has revolutionized the sensitivity and specificity of diagnosis, follow up and response to treatment in almost all fields of clinical practice involving primary ocular pathologies and secondary ocular manifestations in systemic diseases like diabetes mellitus, hypertension, vascular and neurological diseases, thus benefitting non-ophthalmologists as well. Systemically, OCT is proving to be a helpful tool in substantiating early diagnosis in diseases like multiple sclerosis and drug induced retinopathies by detecting early changes in morphology of the retinal nerve fiber layer.

  18. Optic Coherence Tomography of Idiopathic Macular Epiretinal Membranes

    Institute of Scientific and Technical Information of China (English)

    Xing Liu; Yunlan Ling; Jingjing Huang; Xiaoping Zheng

    2002-01-01

    bjectives: To study the characteristics of optical coherence tomography (OCT)inopathic macular epiretinal membranes (IMEM) and the relationship between thethickness offovea and the vision of affected eyes.Methods:A total of 67 cases (73 eyes) with clinical diagnosis of IMEM using direct,indirect ophthalmoscope, three mirror contact lens, fundus color photography or fundusfluorescein angiography (FFA)were examined with OCTResults: Epiretinal membranes (ERMs) with macular edema were found in 32 eyes,proliferative ERMs in 20 eyes, ERMs with macular pseudoholes in 14 eyes and ERMswith laminar macular holes in 7 eyes. Based on OCT, the ERMs were clearly andpartially seperated from the retinal (27 eyes, 38.36% ), the retinal thickness of thefovea was the thickest in the proliferative ERMs and the thinnest in the ERMs withlaminar macular holes. The statistical analysis showed there was a negative correlationbetween the thickness of fovea and visual acuity ( r = - 0. 454, P = 0. 000).Conclusion:There were four types of images of OCT in IMEM: ERMs with macularedema, proliferative ERMs, ERMs with macular pseudohole and ERMs with laminarmacular hole; and the thicker the fovea under the OCT, the poorer the vision acuity in the affected eyes with ERMs.

  19. Ex vivo brain tumor analysis using spectroscopic optical coherence tomography

    Science.gov (United States)

    Lenz, Marcel; Krug, Robin; Welp, Hubert; Schmieder, Kirsten; Hofmann, Martin R.

    2016-03-01

    A big challenge during neurosurgeries is to distinguish between healthy tissue and cancerous tissue, but currently a suitable non-invasive real time imaging modality is not available. Optical Coherence Tomography (OCT) is a potential technique for such a modality. OCT has a penetration depth of 1-2 mm and a resolution of 1-15 μm which is sufficient to illustrate structural differences between healthy tissue and brain tumor. Therefore, we investigated gray and white matter of healthy central nervous system and meningioma samples with a Spectral Domain OCT System (Thorlabs Callisto). Additional OCT images were generated after paraffin embedding and after the samples were cut into 10 μm thin slices for histological investigation with a bright field microscope. All samples were stained with Hematoxylin and Eosin. In all cases B-scans and 3D images were made. Furthermore, a camera image of the investigated area was made by the built-in video camera of our OCT system. For orientation, the backsides of all samples were marked with blue ink. The structural differences between healthy tissue and meningioma samples were most pronounced directly after removal. After paraffin embedding these differences diminished. A correlation between OCT en face images and microscopy images can be seen. In order to increase contrast, post processing algorithms were applied. Hence we employed Spectroscopic OCT, pattern recognition algorithms and machine learning algorithms such as k-means Clustering and Principal Component Analysis.

  20. Screening cervical and oesophageal tissues using optical coherence tomography

    Science.gov (United States)

    Erry, Gavin R. G.; Bazant-Hegemark, Florian; Read, Mike D.; Stone, Nicholas

    2011-06-01

    Optical Coherence Tomography (OCT) is a technique that allows imaging tissue in three spatial dimensions. Such a technique makes it possible to examine the subsurface of the tissue. The depth of penetration into the tissue can be tailored by tuning the wavelength of the light source. While in some cases it is desirable to obtain deep penetration of the sample, when scanning for cancerous changes, it may only be necessary to penetrate the first few hundred micrometres. The use of a shorter wavelength, while decreasing the penetration depth, will improve the resolution of the instrument. While images from OCT systems contain speckle and other artefacts, there are methods of evaluating the information by using image processing techniques. Of particular interest is the scattering coefficient that can be derived from the OCT data. Using discriminant techniques on the scattering data (such as principal components analysis), gives a sensitive way of differentiating between changes in structure in the tissue. An extensive data collection was performed on cervical tissue using samples that ranged from normal to invasive cancer. The histopathology of each sample was gathered and was classified from normal to cancer. The scattering profiles of the data were averaged and gradient analysis was performed, showing that for small distances into the sample there is a significant difference between scattering profiles between cancerous and normal tissue. PCA was also performed on the data showing grouping into various stages of cancer.

  1. Towards quantitative analysis of retinal features in optical coherence tomography.

    Science.gov (United States)

    Baroni, Maurizio; Fortunato, Pina; La Torre, Agostino

    2007-05-01

    The purpose of this paper was to propose a new computer method for quantitative evaluation of representative features of the retina using optical coherence tomography (OCT). A multi-step approach was devised and positively tested for segmentation of the three main retinal layers: the vitreo-retinal interface and the inner and outer retina. Following a preprocessing step, three regions of interest were delimited. Significant peaks corresponding to high and low intensity strips were located along the OCT A-scan lines and accurate boundaries between different layers were obtained by maximizing an edge likelihood function. For a quantitative description, thickness measurement, densitometry, texture and curvature analyses were performed. As a first application, the effect of intravitreal injection of triamcinolone acetonide (IVTA) for the treatment of vitreo-retinal interface syndrome was evaluated. Almost all the parameters, measured on a set of 16 pathologic OCT images, were statistically different before and after IVTA injection (pvitreo-retinal interface and in the inner retinal layers. Texture parameters in the inner and outer retinal layers significantly correlated with the visual acuity restoration. According to these findings an IVTA injection might be considered a possible alternative to surgery for selected patients. In conclusion, the proposed approach appeared to be a promising tool for the investigation of tissue changes produced by pathology and/or therapy.

  2. Analysis of Craniocardiac Malformations in Xenopus using Optical Coherence Tomography

    Science.gov (United States)

    Deniz, Engin; Jonas, Stephan; Hooper, Michael; N. Griffin, John; Choma, Michael A.; Khokha, Mustafa K.

    2017-01-01

    Birth defects affect 3% of children in the United States. Among the birth defects, congenital heart disease and craniofacial malformations are major causes of mortality and morbidity. Unfortunately, the genetic mechanisms underlying craniocardiac malformations remain largely uncharacterized. To address this, human genomic studies are identifying sequence variations in patients, resulting in numerous candidate genes. However, the molecular mechanisms of pathogenesis for most candidate genes are unknown. Therefore, there is a need for functional analyses in rapid and efficient animal models of human disease. Here, we coupled the frog Xenopus tropicalis with Optical Coherence Tomography (OCT) to create a fast and efficient system for testing craniocardiac candidate genes. OCT can image cross-sections of microscopic structures in vivo at resolutions approaching histology. Here, we identify optimal OCT imaging planes to visualize and quantitate Xenopus heart and facial structures establishing normative data. Next we evaluate known human congenital heart diseases: cardiomyopathy and heterotaxy. Finally, we examine craniofacial defects by a known human teratogen, cyclopamine. We recapitulate human phenotypes readily and quantify the functional and structural defects. Using this approach, we can quickly test human craniocardiac candidate genes for phenocopy as a critical first step towards understanding disease mechanisms of the candidate genes. PMID:28195132

  3. Three-dimensional calibration targets for optical coherence tomography

    Science.gov (United States)

    Gabriele Sandrian, Michelle; Tomlins, Pete; Woolliams, Peter; Rasakanthan, Janarthanan; Lee, Graham C.; Yang, Anna; Považay, Boris; Alex, Aneesh; Sugden, Kate; Drexler, Wolfgang

    2012-03-01

    The recent expansion of clinical applications for optical coherence tomography (OCT) is driving the development of approaches for consistent image acquisition. There is a simultaneous need for time-stable, easy-to-use imaging targets for calibration and standardization of OCT devices. We present calibration targets consisting of three-dimensional structures etched into nanoparticle-embedded resin. Spherical iron oxide nanoparticles with a predominant particle diameter of 400 nm were homogeneously dispersed in a two part polyurethane resin and allowed to harden overnight. These samples were then etched using a precision micromachining femtosecond laser with a center wavelength of 1026 nm, 100kHz repetition rate and 450 fs pulse duration. A series of lines in depth were etched, varying the percentage of inscription energy and speed of the translation stage moving the target with respect to the laser. Samples were imaged with a dual wavelength spectral-domain OCT system (λ=800nm, ▵λ~180nm, and λ=1325nm, ▵λ~100nm) and point-spread function of nanoparticles within the target was measured.

  4. Using optical coherence tomography to detect peripheral pulmonary thrombi

    Institute of Scientific and Technical Information of China (English)

    HONG Cheng; WANG Wei; ZHONG Nan-shan; ZENG Guang-qiao; WU Hua

    2012-01-01

    Background Optical coherence tomography (OCT) is a new imaging technique capable of obtaining high-resolution intravascular images of small vessels and has been widely used in interventional cardiology.However,application of OCT in peripheral pulmonary arteries in patients has been seldom documented.Methods Three patients who were highly suspected peripheral pulmonary arteries thrombi and had undergone CT pulmonary angiography but tested negative for thrombi in peripheral pulmonary arteries were enrolled.Subsequently,OCT imaging was performed in peripheral pulmonary arteries.The patients received more than three-month anticoagulative treatment if thrombi were detected by OCT.Thereafter,OCT re-evaluation of the thrombolized blood vessels detected earlier was performed.The changes of thrombi before and after anticoagulative treatment were compared.Results Three patients underwent OCT imaging of peripheral pulmonary arteries.Thrombi were found in most of imaged vessels in these patients.Red and white thrombi can be differentiated,according to features of the thrombus on OCT images.After anticoagulation treatment,these patients' symptoms and hypoxemia improved.Repeated OCT imaging showed that most thrombi disappeared or became smaller.Conclusion OCT may be used as a potential tool for detecting peripheral pulmonary artery thrombi and differentiating red thrombi from white ones.

  5. The potential of optical coherence tomography for diagnosing meniscal pathology

    Science.gov (United States)

    Hang-Yin Ling, Carrie; Pozzi, Antonio; Thieman, Kelley M.; Tonks, Catherine A.; Guo, Shuguang; Xie, Huikai; Horodyski, MaryBeth

    2010-04-01

    Meniscal tears are often associated with anterior cruciate ligament (ACL) injury and may lead to pain and discomfort in humans. Maximal preservation of meniscal tissue is highly desirable to mitigate the progression of osteoarthritis. Guidelines of which meniscal tears are amenable to repair and what part of damaged tissues should be removed are elusive and lacking consensus. Images of microstructural changes in meniscus would potentially guide the surgeons to manage the meniscal tears better, but the resolution of current diagnostic techniques is limited for this application. In this study, we demonstrated the feasibility of using optical coherence tomography (OCT) for the diagnosis of meniscal pathology. Torn medial menisci were collected from dogs with ACL insufficiency. The torn meniscus was divided into three tissue samples and scanned by OCT and scanning electron microscopy (SEM). OCT and SEM images of torn menisci were compared. Each sample was evaluated for gross and microstructural abnormalities and reduction or loss of birefringence from the OCT images. The abnormalities detected with OCT were described for each type of tear. OCT holds promise in non-destructive and fast assessment of microstructural changes and tissue birefringence of meniscal tears. Future development of intraoperative OCT may help surgeons in the decision making of meniscal treatment.

  6. Marginal integrity evaluation of dental composite using optical coherence tomography

    Science.gov (United States)

    Stan, Adrian-Tudor; Cojocariu, Andreea-Codruta; Antal, Anca Adriana; Topala, Florin; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Duma, Virgil-Florin; Podoleanu, Adrian Gh.

    2016-03-01

    In clinical dental practice it is often difficult or even impossible to distinguish and control interfacial adhesive defects from adhesive restorations using visual inspection or other traditional diagnostic methods. Nonetheless, non-invasive biomedical imaging methods like Optical Coherence Tomography (OCT) may provide a better view in this diagnostic outline. The aim of this study is to explore evaluations of the marginal adaptation of class I resin composites restorations using Time Domain (TD) OCT. Posterior human teeth have been chosen for this study. The teeth were stored in 0.9% physiological saline solution prior to use. A classical round-shaped class I cavity was prepared and cavities were restored with Charisma Diamond composite by Heraeus Kulzer and using a system of etch and rinse boding. The specimens were subjected to water storage and then to thermo-cycling. Three dimensional (3-D) scans of the restoration were obtained using a TD-OCT system centered at a 1300 nm wavelength. Open marginal adaptation at the interfaces and gaps inside the composite resins materials were identified using the proposed method. In conclusion, OCT has numerous advantages which justify its use for in vitro, as well as for in vivo studies. It can therefore be considered for non-invasive and fast detection of gaps at the restoration interface.

  7. Spectral Domain Optical Coherence Tomography Findings in Posterior Microphthalmia

    Directory of Open Access Journals (Sweden)

    Emine Tınkır Kayıtmazbatır

    2014-05-01

    Full Text Available The retinal spectral domain optical coherence tomography (SD-OCT findings of two posterior microphthalmia cases are presented in this case report. For this purpose, the findings of two siblings aged five and seven years who presented to our clinic with the complain of far-sightedness and high hypermetropia were evaluated. Both cases diagnosed to have posterior microphthalmia demonstrated normal biomicroscopic anterior segment examination and gonioscopy findings and the axial lengths were measured to be shorter than 17mm. The SD-OCT analysis of papillomacular folds detected in fundus examination revealed contribution of only neurosensorial retina. Beneath the retinal fold, we observed bilateral cysts in the intraretinal area in one of the cases and a triangle-shaped hyporeflective space with an apex corresponding to that of the retinal fold in the subretinal area in both cases. SD-OCT is an adjunctive imaging tool for diagnosis and follow-up of degenerative changes in posterior microphthalmia. These changes may be also important for visual prognosis. (Turk J Ophthalmol 2014; 44: 240-2

  8. Video-rate volumetric optical coherence tomography-based microangiography

    Science.gov (United States)

    Baran, Utku; Wei, Wei; Xu, Jingjiang; Qi, Xiaoli; Davis, Wyatt O.; Wang, Ruikang K.

    2016-04-01

    Video-rate volumetric optical coherence tomography (vOCT) is relatively young in the field of OCT imaging but has great potential in biomedical applications. Due to the recent development of the MHz range swept laser sources, vOCT has started to gain attention in the community. Here, we report the first in vivo video-rate volumetric OCT-based microangiography (vOMAG) system by integrating an 18-kHz resonant microelectromechanical system (MEMS) mirror with a 1.6-MHz FDML swept source operating at ˜1.3 μm wavelength. Because the MEMS scanner can offer an effective B-frame rate of 36 kHz, we are able to engineer vOMAG with a video rate up to 25 Hz. This system was utilized for real-time volumetric in vivo visualization of cerebral microvasculature in mice. Moreover, we monitored the blood perfusion dynamics during stimulation within mouse ear in vivo. We also discussed this system's limitations. Prospective MEMS-enabled OCT probes with a real-time volumetric functional imaging capability can have a significant impact on endoscopic imaging and image-guided surgery applications.

  9. Optical coherence tomography use in the diagnosis of enamel defects

    Science.gov (United States)

    Al-Azri, Khalifa; Melita, Lucia N.; Strange, Adam P.; Festy, Frederic; Al-Jawad, Maisoon; Cook, Richard; Parekh, Susan; Bozec, Laurent

    2016-03-01

    Molar incisor hypomineralization (MIH) affects the permanent incisors and molars, whose undermineralized matrix is evidenced by lesions ranging from white to yellow/brown opacities to crumbling enamel lesions incapable of withstanding normal occlusal forces and function. Diagnosing the condition involves clinical and radiographic examination of these teeth, with known limitations in determining the depth extent of the enamel defects in particular. Optical coherence tomography (OCT) is an emerging hard and soft tissue imaging technique, which was investigated as a new potential diagnostic method in dentistry. A comparison between the diagnostic potential of the conventional methods and OCT was conducted. Compared to conventional imaging methods, OCT gave more information on the structure of the enamel defects as well as the depth extent of the defects into the enamel structure. Different types of enamel defects were compared, each type presenting a unique identifiable pattern when imaged using OCT. Additionally, advanced methods of OCT image analysis including backscattered light intensity profile analysis and enface reconstruction were performed. Both methods confirmed the potential of OCT in enamel defects diagnosis. In conclusion, OCT imaging enabled the identification of the type of enamel defect and the determination of the extent of the enamel defects in MIH with the advantage of being a radiation free diagnostic technique.

  10. Determination of dental decay rates with optical coherence tomography

    Science.gov (United States)

    Freitas, A. Z.; Zezell, D. M.; Mayer, M. P. A.; Ribeiro, A. C.; Gomes, A. S. L.; Vieira, N. D., Jr.

    2009-12-01

    We report the use of optical coherence tomography (OCT) to detect and quantify demineralization process induced by S. mutans biofilm in third molars human teeth. Artificial lesions were induced by a S. mutans microbiological culture and the samples (N = 50) were divided into groups according to the demineralization time: 3, 5, 7, 9, and 11 days. The OCT system was implemented using a light source delivering an average power of 96 μW in the sample arm, and spectral characteristics allowing 23 μm of axial resolution. The images were produced with lateral scans step of 10 μm and analyzed individually. As a result of the evaluation of theses images, lesion depth was calculated as function of demineralization time. The depth of the lesion in the root dentine increased from 70 μm to 230 μm (corrected by the enamel refraction index, 1.62 @ 856 nm), depending of exposure time. The lesion depth in root dentine was correlated to demineralization time, showing that it follows a geometrical progression like a bacteria growth law.

  11. Evaluation of fingerprint deformation using optical coherence tomography

    Science.gov (United States)

    Gutierrez da Costa, Henrique S.; Maxey, Jessica R.; Silva, Luciano; Ellerbee, Audrey K.

    2014-02-01

    Biometric identification systems have important applications to privacy and security. The most widely used of these, print identification, is based on imaging patterns present in the fingers, hands and feet that are formed by the ridges, valleys and pores of the skin. Most modern print sensors acquire images of the finger when pressed against a sensor surface. Unfortunately, this pressure may result in deformations, characterized by changes in the sizes and relative distances of the print patterns, and such changes have been shown to negatively affect the performance of fingerprint identification algorithms. Optical coherence tomography (OCT) is a novel imaging technique that is capable of imaging the subsurface of biological tissue. Hence, OCT may be used to obtain images of subdermal skin structures from which one can extract an internal fingerprint. The internal fingerprint is very similar in structure to the commonly used external fingerprint and is of increasing interest in investigations of identify fraud. We proposed and tested metrics based on measurements calculated from external and internal fingerprints to evaluate the amount of deformation of the skin. Such metrics were used to test hypotheses about the differences of deformation between the internal and external images, variations with the type of finger and location inside the fingerprint.

  12. Comparison of diffuse optical tomography of human breast with whole-body and breast-only positron emission tomography.

    Science.gov (United States)

    Konecky, Soren D; Choe, Regine; Corlu, Alper; Lee, Kijoon; Wiener, Rony; Srinivas, Shyam M; Saffer, Janet R; Freifelder, Richard; Karp, Joel S; Hajjioui, Nassim; Azar, Fred; Yodh, Arjun G

    2008-02-01

    We acquire and compare three-dimensional tomographic breast images of three females with suspicious masses using diffuse optical tomography (DOT) and positron emission tomography (PET). Co-registration of DOT and PET images was facilitated by a mutual information maximization algorithm. We also compared DOT and whole-body PET images of 14 patients with breast abnormalities. Positive correlations were found between total hemoglobin concentration and tissue scattering measured by DOT, and fluorodeoxyglucose (18F-FDG) uptake. In light of these observations, we suggest potential benefits of combining both PET and DOT for characterization of breast lesions.

  13. Application of optical coherence tomography attenuation imaging for quantification of optical properties in medulloblastoma

    Science.gov (United States)

    Vuong, Barry; Skowron, Patryk; Kiehl, Tim-Rasmus; Kyan, Matthew; Garzia, Livia; Genis, Helen; Sun, Cuiru; Taylor, Michael D.; Yang, Victor X. D.

    2015-03-01

    The hemodynamic environment is known to play a crucial role in the progression, rupture, and treatment of intracranial aneurysms. Currently there is difficulty assessing and measuring blood flow profiles in vivo. An emerging high resolution imaging modality known as split spectrum Doppler optical coherence tomography (ssDOCT) has demonstrated the capability to quantify hemodynamic patterns as well as arterial microstructural changes. In this study, we present a novel in vitro method to acquire precise blood flow patterns within a patient- specific aneurysm silicone flow models using ssDOCT imaging. Computational fluid dynamics (CFD) models were generated to verify ssDOCT results.

  14. CCD imaging for optical tomography of gel radiation dosimeters.

    Science.gov (United States)

    Wolodzko, J G; Marsden, C; Appleby, A

    1999-11-01

    Several investigations have been carried out by a number of researchers over the past few years to evaluate the utility of imaging gel dosimeters for the three-dimensional measurement of radiation fields. These have been proposed to be of particular value in mapping radiation dose distributions associated with emerging and complex approaches to cancer treatment such as conformal (CRT), intensity modulated (IMRT), "gamma knife," and pencil beam radiotherapies. Imaging of the gels has been successfully accomplished with clinical MRI units and via laser-based optical scanning. However, neither of these methods is generally accessible to all potential users, limiting the broader study and implementation of this valuable tool. We report here the design, methodology, and results of a preliminary study carried out to evaluate the utility of a new, inexpensive, and simplified approach to tomographic imaging of gel radiation dosimeters. For the purpose of this initial investigation, an array of liquid scintillation vials was prepared, containing a ferrous sulphate xylenol orange (FSX) gelatin formulation. The FSX formulation undergoes a change in optical absorption characteristics following irradiation, and the resulting color change can be observed visually. The vials were irradiated individually to different doses. Three-dimensional imaging was accomplished by tomographic reconstruction from two-dimensional optical images acquired using a diffuse, fluorescent light source, a digital charge-coupled device camera, single-photon-emission-computed tomography software, and other simple components designed by the authors. The resulting transverse images were evaluated through a region-of-interest (ROI) analysis to obtain the average change in image density in each vial as a function of radiation dose. These measured ROI values were subjected to a linear regression analysis to fit them to a straight line, and to determine the goodness of fit. Results from multiple imaging trials

  15. Three dimensional image reconstruction based on a wide-field optical coherence tomography system

    Science.gov (United States)

    Feng, Yinqi; Feng, Shengtong; Zhang, Min; Hao, Junjun

    2014-07-01

    Wide-field optical coherence tomography has a promising application for its high scanning rate and resolution. The principle of a wide-field optical coherence tomography system is described, and 2D images of glass slides are reconstructed using eight-stepped phase-shifting method in the system. Using VC6.0 and OpenGL programming, 3D images are reconstructed based on the Marching Cube algorithm with 2D image sequences. The experimental results show that the depth detection and three-dimensional tomography for translucent materials could be implemented efficiently in the WFOCT system.

  16. Optical clearing of melanoma in vivo: characterization by diffuse reflectance spectroscopy and optical coherence tomography

    Science.gov (United States)

    Pires, Layla; Demidov, Valentin; Vitkin, I. Alex; Bagnato, Vanderlei; Kurachi, Cristina; Wilson, Brian C.

    2016-08-01

    Melanoma is the most aggressive type of skin cancer, with significant risk of fatality. Due to its pigmentation, light-based imaging and treatment techniques are limited to near the tumor surface, which is inadequate, for example, to evaluate the microvascular density that is associated with prognosis. White-light diffuse reflectance spectroscopy (DRS) and near-infrared optical coherence tomography (OCT) were used to evaluate the effect of a topically applied optical clearing agent (OCA) in melanoma in vivo and to image the microvascular network. DRS was performed using a contact fiber optic probe in the range from 450 to 650 nm. OCT imaging was performed using a swept-source system at 1310 nm. The OCT image data were processed using speckle variance and depth-encoded algorithms. Diffuse reflectance signals decreased with clearing, dropping by ˜90% after 45 min. OCT was able to image the microvasculature in the pigmented melanoma tissue with good spatial resolution up to a depth of ˜300 μm without the use of OCA; improved contrast resolution was achieved with optical clearing to a depth of ˜750 μm in tumor. These findings are relevant to potential clinical applications in melanoma, such as assessing prognosis and treatment responses. Optical clearing may also facilitate the use of light-based treatments such as photodynamic therapy.

  17. All fiber optics circular-state swept source polarization-sensitive optical coherence tomography.

    Science.gov (United States)

    Lin, Hermann; Kao, Meng-Chun; Lai, Chih-Ming; Huang, Jyun-Cin; Kuo, Wen-Chuan

    2014-02-01

    A swept source (SS)-based circular-state (CS) polarization-sensitive optical coherence tomography (PS-OCT) constructed entirely with polarization-maintaining fiber optics components is proposed with the experimental verification. By means of the proposed calibration scheme, bulk quarter-wave plates can be replaced by fiber optics polarization controllers to, therefore, realize an all-fiber optics CS SSPS-OCT. We also present a numerical dispersion compensation method, which can not only enhance the axial resolution, but also improve the signal-to-noise ratio of the images. We demonstrate that this compact and portable CS SSPS-OCT system with an accuracy comparable to bulk optics systems requires less stringent lens alignment and can possibly serve as a technology to realize PS-OCT instrument for clinical applications (e.g., endoscopy). The largest deviations in the phase retardation (PR) and fast-axis (FA) angle due to sample probe in the linear scanning and a rotation angle smaller than 65 deg were of the same order as those in stationary probe setups. The influence of fiber bending on the measured PR and FA is also investigated. The largest deviations of the PR were 3.5 deg and the measured FA change by ~12 to 21 deg. Finally, in vivo imaging of the human fingertip and nail was successfully demonstrated with a linear scanning probe.

  18. In vivo optical coherence tomography of stimulus-evoked intrinsic optical signals in mouse retinas

    Science.gov (United States)

    Wang, Benquan; Lu, Yiming; Yao, Xincheng

    2016-09-01

    Intrinsic optical signal (IOS) imaging promises a noninvasive method for advanced study and diagnosis of eye diseases. Before pursuing clinical applications, it is essential to understand anatomic and physiological sources of retinal IOSs and to establish the relationship between IOS distortions and eye diseases. The purpose of this study was designed to demonstrate the feasibility of in vivo IOS imaging of mouse models. A high spatiotemporal resolution spectral domain optical coherence tomography (SD-OCT) was employed for depth-resolved retinal imaging. A custom-designed animal holder equipped with ear bar and bite bar was used to minimize eye movements. Dynamic OCT imaging revealed rapid IOS from the photoreceptor's outer segment immediately after the stimulation delivery, and slow IOS changes were observed from inner retinal layers. Comparative photoreceptor IOS and electroretinography recordings suggested that the fast photoreceptor IOS may be attributed to the early stage of phototransduction before the hyperpolarization of retinal photoreceptor.

  19. Optical coherence tomography: Monte Carlo simulation and improvement by optical amplification

    DEFF Research Database (Denmark)

    Tycho, Andreas

    2002-01-01

    An advanced novel Monte Carlo simulation model of the detection process of an optical coherence tomography (OCT) system is presented. For the first time it is shown analytically that the applicability of the incoherent Monte Carlo approach to model the heterodyne detection process of an OCT system...... model of the OCT signal. The OCT signal from a scattering medium are obtained for several beam and sample geometries using the new Monte Carlo model, and when comparing to results of an analytical model based on the extended Huygens-Fresnel principle excellent agreement is obtained. With the greater...... flexibility of Monte Carlo simulations, this new model is demonstrated to be excellent as a numerical phantom, i.e., as a substitute for otherwise difficult experiments. Finally, a new model of the signal-to-noise ratio (SNR) of an OCT system with optical amplification of the light reflected from the sample...

  20. Optical Sensing Method for Screening Disease in Melon Seeds by Using Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Jeehyun Kim

    2011-10-01

    Full Text Available We report a noble optical sensing method to diagnose seed abnormalities using optical coherence tomography (OCT. Melon seeds infected with Cucumber green mottle mosaic virus (CGMMV were scanned by OCT. The cross-sectional sensed area of the abnormal seeds showed an additional subsurface layer under the surface which is not found in normal seeds. The presence of CGMMV in the sample was examined by a blind test (n = 140 and compared by the reverse transcription-polymerase chain reaction. The abnormal layers (n = 40 were quantitatively investigated using A-scan sensing analysis and statistical method. By utilizing 3D OCT image reconstruction, we confirmed the distinctive layers on the whole seeds. These results show that OCT with the proposed data processing method can systemically pick up morphological modification induced by viral infection in seeds, and, furthermore, OCT can play an important role in automatic screening of viral infections in seeds.

  1. Optical coherence tomography of the rat cavernous nerves

    Science.gov (United States)

    Fried, Nathaniel M.; Rais-Bahrami, Soroush; Lagoda, Gwen A.; Chuang, Ying; Burnett, Arthur L.; Su, Li-Ming

    2007-02-01

    Improvements in identification, imaging, and visualization of the cavernous nerves during radical prostatectomy, which are responsible for erectile function, may improve nerve preservation and postoperative potency. Optical coherence tomography (OCT) is capable of real-time, high-resolution, cross-sectional, in vivo tissue imaging. The rat prostate serves as an excellent model for studying the use of OCT for imaging the cavernous nerves, as the rat cavernous nerve is a large, visible, and distinct bundle allowing for easy identification with OCT in addition to histologic confirmation. Imaging was performed with the Niris OCT system and a handheld 8 Fr probe, capable of acquiring real-time images with 11-μm axial and 25-μm lateral resolution in tissue. Open surgical exposure of the prostate was performed on a total of 6 male rats, and OCT images of the prostate, cavernous nerve, pelvic plexus ganglion, seminal vesicle, blood vessels, and periprostatic fat were acquired. Cavernous nerve electrical stimulation with simultaneous intracorporeal pressure measurements was performed to confirm proper identification of the cavernous nerves. The prostate and cavernous nerves were also processed for histologic analysis and further confirmation. Cross-sectional and longitudinal OCT images of the cavernous nerves were acquired and compared with histologic sections. The cavernous nerve and ganglion could be differentiated from the surrounding prostate gland, seminal vesicle, blood vessels, bladder, and fatty tissue. We report preliminary results of OCT images of the rat cavernous nerves with histologic correlation and erectile stimulation measurements, thus providing interpretation of prostate structures as they appear in OCT images.

  2. Automatic segmentation of choroidal thickness in optical coherence tomography.

    Science.gov (United States)

    Alonso-Caneiro, David; Read, Scott A; Collins, Michael J

    2013-01-01

    The assessment of choroidal thickness from optical coherence tomography (OCT) images of the human choroid is an important clinical and research task, since it provides valuable information regarding the eye's normal anatomy and physiology, and changes associated with various eye diseases and the development of refractive error. Due to the time consuming and subjective nature of manual image analysis, there is a need for the development of reliable objective automated methods of image segmentation to derive choroidal thickness measures. However, the detection of the two boundaries which delineate the choroid is a complicated and challenging task, in particular the detection of the outer choroidal boundary, due to a number of issues including: (i) the vascular ocular tissue is non-uniform and rich in non-homogeneous features, and (ii) the boundary can have a low contrast. In this paper, an automatic segmentation technique based on graph-search theory is presented to segment the inner choroidal boundary (ICB) and the outer choroidal boundary (OCB) to obtain the choroid thickness profile from OCT images. Before the segmentation, the B-scan is pre-processed to enhance the two boundaries of interest and to minimize the artifacts produced by surrounding features. The algorithm to detect the ICB is based on a simple edge filter and a directional weighted map penalty, while the algorithm to detect the OCB is based on OCT image enhancement and a dual brightness probability gradient. The method was tested on a large data set of images from a pediatric (1083 B-scans) and an adult (90 B-scans) population, which were previously manually segmented by an experienced observer. The results demonstrate the proposed method provides robust detection of the boundaries of interest and is a useful tool to extract clinical data.

  3. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography.

    Directory of Open Access Journals (Sweden)

    Mario E Giardini

    Full Text Available Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT. Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1 accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord, and 2 identify the position of a recording microelectrode approaching and inserting into the cord tissue 3 check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma for damage recognition, diagnosis and fast image-guided intervention.

  4. Optical coherence tomography using the Niris system in otolaryngology

    Science.gov (United States)

    Rubinstein, Marc; Armstrong, William B.; Djalilian, Hamid R.; Crumley, Roger L.; Kim, Jason H.; Nguyen, Quoc A.; Foulad, Allen I.; Ghasri, Pedram E.; Wong, Brian J. F.

    2009-02-01

    Objectives: To determine the feasibility and accuracy of the Niris Optical Coherence Tomography (OCT) system in imaging of the mucosal abnormalities of the head and neck. The Niris system is the first commercially available OCT device for applications outside ophthalmology. Methods: We obtained OCT images of benign, premalignant and malignant lesions throughout the head and neck, using the Niris OCT imaging system (Imalux, Cleveland, OH). This imaging system has a tissue penetration depth of approximately 1-2mm, a scanning range of 2mm and a spatial depth resolution of approximately 10-20μm. Imaging was performed in the outpatient setting and in the operating room using a flexible probe. Results: High-resolution cross-sectional images from the oral cavity, nasal cavity, ears and larynx showed distinct layers and structures such as mucosa layer, basal membrane and lamina propria, were clearly identified. In the pathology images disruption of the basal membrane was clearly shown. Device set-up took approximately 5 minutes and the image acquisition was rapid. The system can be operated by the person performing the exam. Conclusions: The Niris system is non invasive and easy to incorporate into the operating room and the clinic. It requires minimal set-up and requires only one person to operate. The unique ability of the OCT offers high-resolution images showing the microanatomy of different sites. OCT imaging with the Niris device potentially offers an efficient, quick and reliable imaging modality in guiding surgical biopsies, intra-operative decision making, and therapeutic options for different otolaryngologic pathologies and premalignant disease.

  5. Optical coherence tomography for blood glucose monitoring through signal attenuation

    Science.gov (United States)

    De Pretto, Lucas R.; Yoshimura, Tania M.; Ribeiro, Martha S.; de Freitas, Anderson Z.

    2016-03-01

    Development of non-invasive techniques for glucose monitoring is crucial to improve glucose control and treatment adherence in patients with diabetes. Hereafter, Optical Coherence Tomography (OCT) may offer a good alternative for portable glucometers, since it uses light to probe samples. Changes in the object of interest can alter the intensity of light returning from the sample and, through it, one can estimate the sample's attenuation coefficient (μt) of light. In this work, we aimed to explore the behavior of μt of mouse's blood under increasing glucose concentrations. Different samples were prepared in four glucose concentrations using a mixture of heparinized blood, phosphate buffer saline and glucose. Blood glucose concentrations were measured with a blood glucometer, for reference. We have also prepared other samples diluting the blood in isotonic saline solution to check the effect of a higher multiple-scattering component on the ability of the technique to differentiate glucose levels based on μt. The OCT system used was a commercial Spectral Radar OCT with 930 nm central wavelength and spectral bandwidth (FWHM) of 100 nm. The system proved to be sensitive for all blood glucose concentrations tested, with good correlations with the obtained attenuation coefficients. A linear tendency was observed, with an increase in attenuation with higher values of glucose. Statistical difference was observed between all groups (p<0.001). This work opens the possibility towards a non-invasive diagnostic modality using OCT for glycemic control, which eliminates the use of analytes and/or test strips, as in the case with commercially available glucometers.

  6. Role of Optical Coherence Tomography in Assessing Anterior Chamber Angles

    Science.gov (United States)

    Kochupurakal, Reema Thomas; Jha, Kirti Nath; Rajalakshmi, A.R.; Nagarajan, Swathi; Ezhumalai, G.

    2016-01-01

    Introduction Gonioscopy is the gold standard in assessing anterior chamber angles. However, interobserver variations are common and there is a need for reliable objective method of assessment. Aim To compare the anterior chamber angle by gonioscopy and Spectral Domain Optical Coherence Tomography (SD-OCT) in individuals with shallow anterior chamber. Materials and Methods This comparative observational study was conducted in a rural tertiary multi-speciality teaching hospital. A total of 101 eyes of 54 patients with shallow anterior chamber on slit lamp evaluation were included. Anterior chamber angle was graded by gonioscopy using the shaffer grading system. Angles were also assessed by SD-OCT with Trabecular Iris Angle (TIA) and Angle Opening Distance (AOD). Chi-square test, sensitivity, specificity, positive and negative predictive value to find correlation between OCT parameters and gonioscopy grading. Results Females represented 72.7%. The mean age was 53.93 ±8.24 years and mean anterior chamber depth was 2.47 ± 0.152 mm. Shaffer grade ≤ 2 were identified in 95(94%) superior, 42(41.5%) inferior, 65(64.3%) nasal and 57(56.4%) temporal quadrants. Cut-off values of TIA ≤ 22° and AOD ≤ 290 μm were taken as narrow angles on SD-OCT. TIA of ≤ 22° were found in 88(92.6%) nasal and 87(87%) temporal angles. AOD of ≤ 290 μm was found in 73(76.8%) nasal and 83(83%) temporal quadrants. Sensitivity in detecting narrow angles was 90.7% and 82.2% for TIA and AOD, while specificity was 11.7% and 23.4%, respectively. Conclusion Individuals were found to have narrow angles more with SD-OCT. Sensitivity was high and specificity was low in detecting narrow angles compared to gonioscopy, making it an unreliable tool for screening. PMID:27190851

  7. A proposed fibre optic time domain optical coherence tomography system using a micro-photonic stationary optical delay line

    Science.gov (United States)

    Jansz, Paul Vernon; Wild, Graham; Hinckley, Steven

    2008-04-01

    Conventional time domain Optical Coherence Tomography (OCT) relies on a reference Optical Delay Line (ODL). These reference ODLs require the physical movement of a mirror to scan a given depth range. This movement results in instrument degradation. We propose a new optical fibre based time domain OCT system that makes use of a micro-photonic structure as a stationary ODL. The proposed system uses an in-fibre interferometer, either a Michelson or a Mach-Zhender. The reference ODL makes use of a collimator to expand the light from the optical fibre. This is them expanded in one dimension via planar optics, that is, a cylindrical lens based telescope, using a concave and convex lens. The expanded beam is them passed through a transmissive Spatial Light Modulator (SLM), specifically a liquid crystal light valve used as an optical switch. Light is then reflected back through the system off the micro-photonic structure. The micro-photonic structure is a one dimensional array of stagged mirror steps, called a Stepped Mirror Structure (SMS). The system enables the selection of discrete optical delay lengths. The proposed ODL is capable of depth hoping and multicasting. We discuss the fabrication of the SMS, which consists of eight steps, each approximately 150 μm high. A change in notch frequency using an in-fibre Mach Zhender interferometer was used to gauge the average step height. The results gave an average step height of 146 μm.

  8. Spectrally encoded common-path fiber-optic-based parallel optical coherence tomography.

    Science.gov (United States)

    Lee, Kye-Sung; Hur, Hwan; Sung, Ha-Young; Kim, I Jong; Kim, Geon-Hee

    2016-09-15

    We demonstrate a fiber-optic-based parallel optical coherence tomography (OCT) using spectrally encoded extended illumination with a common-path handheld probe, where the flexibility and robustness of the system are significantly improved, which is critical in the clinical environment. To the best of our knowledge, we present the first parallel OCT based on fiber optics including a fiber coupler with a sensitivity of 94 dB, which is comparable to that of point-scanning OCT. We also investigated the effect of the phase stability of the fiber-based interferometry on the parallel OCT system by comparing the common-path OCT with two-arm OCT. Using the homemade common-path handheld probe based on a Mirau interferometer, the phase stability was 32 times better than that of the two-arm OCT. The axial resolution of the common-path OCT was measured as 5.1±0.3  μm. To demonstrate the in vivo imaging performance of the fiber-optic-based parallel OCT, human skin was imaged.

  9. Imaging patients with glaucoma using spectral-domain optical coherence tomography and optical microangiography

    Science.gov (United States)

    Auyeung, Kris; Auyeung, Kelsey; Kono, Rei; Chen, Chieh-Li; Zhang, Qinqin; Wang, Ruikang K.

    2015-03-01

    In ophthalmology, a reliable means of diagnosing glaucoma in its early stages is still an open issue. Past efforts, including forays into fluorescent angiography (FA) and early optical coherence tomography (OCT) systems, to develop a potential biomarker for the disease have been explored. However, this development has been hindered by the inability of the current techniques to provide useful depth and microvasculature information of the optic nerve head (ONH), which have been debated as possible hallmarks of glaucoma progression. We reasoned that a system incorporating a spectral-domain OCT (SD-OCT) based Optical Microangiography (OMAG) system, could allow an effective, non-invasive methodology to evaluate effects on microvasculature by glaucoma. SD-OCT follows the principle of light reflection and interference to produce detailed cross-sectional and 3D images of the eye. OMAG produces imaging contrasts via endogenous light scattering from moving particles, allowing for 3D image productions of dynamic blood perfusion at capillary-level resolution. The purpose of this study was to investigate the optic cup perfusion (flow) differences in glaucomatous and normal eyes. Images from three normal and five glaucomatous subjects were analyzed our OCT based OMAG system for blood perfusion and structural images, allowing for comparisons. Preliminary results from blood flow analysis revealed reduced blood perfusion within the whole-depth region encompassing the Lamina Cribrosa in glaucomatous cases as compared to normal ones. We conclude that our OCT-OMAG system may provide promise and viability for glaucoma screening.

  10. Quantification of the optical surface reflection and surface roughness of articular cartilage using optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Saarakkala, Simo; Wang Shuzhe; Huang Yanping; Zheng Yongping [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong (China)], E-mail: simo.saarakkala@uku.fi, E-mail: ypzheng@ieee.org

    2009-11-21

    Optical coherence tomography (OCT) is a promising new technique for characterizing the structural changes of articular cartilage in osteoarthritis (OA). The calculation of quantitative parameters from the OCT signal is an important step to develop OCT as an effective diagnostic technique. In this study, two novel parameters for the quantification of optical surface reflection and surface roughness from OCT measurements are introduced: optical surface reflection coefficient (ORC), describing the amount of a ratio of the optical reflection from cartilage surface with respect to that from a reference material, and OCT roughness index (ORI) indicating the smoothness of the cartilage surface. The sensitivity of ORC and ORI to detect changes in bovine articular cartilage samples after enzymatic degradations of collagen and proteoglycans using collagenase and trypsin enzymes, respectively, was tested in vitro. A significant decrease (p < 0.001) in ORC as well as a significant increase (p < 0.001) in ORI was observed after collagenase digestion. After trypsin digestion, no significant changes in ORC or ORI were observed. To conclude, the new parameters introduced were demonstrated to be feasible and sensitive to detect typical OA-like degenerative changes in the collagen network. From the clinical point of view, the quantification of OCT measurements is of great interest since OCT probes have been already miniaturized and applied in patient studies during arthroscopy or open knee surgery in vivo. Further studies are still necessary to demonstrate the clinical capability of the introduced parameters for naturally occurring early OA changes in the cartilage.

  11. Quantification of the optical surface reflection and surface roughness of articular cartilage using optical coherence tomography

    Science.gov (United States)

    Saarakkala, Simo; Wang, Shu-Zhe; Huang, Yan-Ping; Zheng, Yong-Ping

    2009-11-01

    Optical coherence tomography (OCT) is a promising new technique for characterizing the structural changes of articular cartilage in osteoarthritis (OA). The calculation of quantitative parameters from the OCT signal is an important step to develop OCT as an effective diagnostic technique. In this study, two novel parameters for the quantification of optical surface reflection and surface roughness from OCT measurements are introduced: optical surface reflection coefficient (ORC), describing the amount of a ratio of the optical reflection from cartilage surface with respect to that from a reference material, and OCT roughness index (ORI) indicating the smoothness of the cartilage surface. The sensitivity of ORC and ORI to detect changes in bovine articular cartilage samples after enzymatic degradations of collagen and proteoglycans using collagenase and trypsin enzymes, respectively, was tested in vitro. A significant decrease (p < 0.001) in ORC as well as a significant increase (p < 0.001) in ORI was observed after collagenase digestion. After trypsin digestion, no significant changes in ORC or ORI were observed. To conclude, the new parameters introduced were demonstrated to be feasible and sensitive to detect typical OA-like degenerative changes in the collagen network. From the clinical point of view, the quantification of OCT measurements is of great interest since OCT probes have been already miniaturized and applied in patient studies during arthroscopy or open knee surgery in vivo. Further studies are still necessary to demonstrate the clinical capability of the introduced parameters for naturally occurring early OA changes in the cartilage.

  12. Development and Application of Multifunctional Optical Coherence Tomography

    Science.gov (United States)

    Zhi, Zhongwei

    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

  13. Jones matrix analysis for a polarization-sensitive optical coherence tomography system using fiber-optic components

    OpenAIRE

    Park, B. H.; Pierce, M. C.; Cense, B.; De Boer, MR

    2004-01-01

    We present an analysis for polarization-sensitive optical coherence tomography that facilitates the unrestricted use of fiber and fiber-optic components throughout an interferometer and yields sample birefringence, diattenuation, and relative optic axis orientation. We use a novel Jones matrix approach that compares the polarization states of light reflected from the sample surface with those reflected from within a biological sample for pairs of depth scans. The incident polarization alterna...

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

    NARCIS (Netherlands)

    T. Wang (Teng); A.F.W. van der Steen (Ton); G. van Soest (Gijs)

    2012-01-01

    textabstractEndoscopic 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 o

  15. Edge-promoting reconstruction of absorption and diffusivity in optical tomography

    DEFF Research Database (Denmark)

    Hannukainen, A.; Harhanen, Lauri Oskari; Hyvönen, N.;

    2015-01-01

    In optical tomography a physical body is illuminated with near-infrared light and the resulting outward photon flux is measured at the object boundary. The goal is to reconstruct internal optical properties of the body, such as absorption and diffusivity. In this work, it is assumed that the imaged...

  16. Optimisation of post mortem cardiac computed tomography compared to optical coherence tomography and histopathology - Technical note

    DEFF Research Database (Denmark)

    Precht, Helle; Leth, Peter Mygind; Thygesen, Jesper

    2014-01-01

    Introduction: Coronary atherosclerosis is a leading cause of mortality. New technological developments in computed tomography (CT), including dual energy, iterative reconstructions and high definition scanning, could significantly improve the non-invasive identification of atherosclerosis plaques...

  17. Agreement of angle closure assessments between gonioscopy, anterior segment optical coherence tomography and spectral domain optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    Elton; Lik; Tong; Tay; Vernon; Khet; Yau; Yong; Boon; Ang; Lim; Stelson; Sia; Elizabeth; Poh; Ying; Wong; Leonard; Wei; Leon; Yip

    2015-01-01

    AIM: To determine angle closure agreements between gonioscopy and anterior segment optical coherence tomography(AS-OCT), as well as gonioscopy and spectral domain OCT(SD-OCT). A secondary objective was to quantify inter-observer agreements of AS-OCT and SD-OCT assessments.METHODS: Seventeen consecutive subjects(33 eyes)were recruited from the study hospital’s Glaucoma clinic.Gonioscopy was performed by a glaucomatologist masked to OCT results. OCT images were read independently by 2 other glaucomatologists masked to gonioscopy findings as well as each other’s analyses of OCT images.RESULTS: Totally 84.8% and 45.5% of scleral spurs were visualized in AS-OCT and SD-OCT images respectively(P <0.01). The agreement for angle closure between AS-OCT and gonioscopy was fair at k =0.31(95% confidence interval, CI: 0.03-0.59) and k =0.35(95%CI: 0.07-0.63) for reader 1 and 2 respectively. The agreement for angle closure between SD-OCT and gonioscopy was fair at k =0.21(95% CI: 0.07-0.49) and slight at k =0.17(95% CI: 0.08-0.42) for reader 1 and 2 respectively. The inter-reader agreement for angle closure in AS-OCT images was moderate at 0.51(95% CI: 0.13-0.88). The inter-reader agreement for angle closure in SD-OCT images was slight at 0.18(95% CI: 0.08-0.45).CONCLUSION: Significant proportion of scleral spurs were not visualised with SD-OCT imaging resulting in weaker inter-reader agreements. Identifying other angle landmarks in SD-OCT images will allow more consistent angle closure assessments. Gonioscopy and OCT imaging do not always agree in angle closure assessments but have their own advantages, and should be used together and not exclusively.

  18. 3D Human cartilage surface characterization by optical coherence tomography

    Science.gov (United States)

    Brill, Nicolai; Riedel, Jörn; Schmitt, Robert; Tingart, Markus; Truhn, Daniel; Pufe, Thomas; Jahr, Holger; Nebelung, Sven

    2015-10-01

    Early diagnosis and treatment of cartilage degeneration is of high clinical interest. Loss of surface integrity is considered one of the earliest and most reliable signs of degeneration, but cannot currently be evaluated objectively. Optical Coherence Tomography (OCT) is an arthroscopically available light-based non-destructive real-time imaging technology that allows imaging at micrometre resolutions to millimetre depths. As OCT-based surface evaluation standards remain to be defined, the present study investigated the diagnostic potential of 3D surface profile parameters in the comprehensive evaluation of cartilage degeneration. To this end, 45 cartilage samples of different degenerative grades were obtained from total knee replacements (2 males, 10 females; mean age 63.8 years), cut to standard size and imaged using a spectral-domain OCT device (Thorlabs, Germany). 3D OCT datasets of 8  ×  8, 4  ×  4 and 1  ×  1 mm (width  ×  length) were obtained and pre-processed (image adjustments, morphological filtering). Subsequent automated surface identification algorithms were used to obtain the 3D primary profiles, which were then filtered and processed using established algorithms employing ISO standards. The 3D surface profile thus obtained was used to calculate a set of 21 3D surface profile parameters, i.e. height (e.g. Sa), functional (e.g. Sk), hybrid (e.g. Sdq) and segmentation-related parameters (e.g. Spd). Samples underwent reference histological assessment according to the Degenerative Joint Disease classification. Statistical analyses included calculation of Spearman’s rho and assessment of inter-group differences using the Kruskal Wallis test. Overall, the majority of 3D surface profile parameters revealed significant degeneration-dependent differences and correlations with the exception of severe end-stage degeneration and were of distinct diagnostic value in the assessment of surface integrity. None of the 3D

  19. Differentiating Mild Papilledema and Buried Optic Nerve Head Drusen Using Spectral Domain Optical Coherence Tomography

    Science.gov (United States)

    Kulkarni, Kaushal M.; Pasol, Joshua; Rosa, Potyra R.; Lam, Byron L.

    2013-01-01

    Purpose To evaluate the clinical utility of spectral domain optical coherence tomography (SD-OCT) in differentiating mild papilledema from buried optic nerve head drusen (ONHD). Design Comparative case series. Participants 16 eyes of 9 patients with ultrasound-proven buried ONHD, 12 eyes of 6 patients with less than or equal to Frisén grade 2 papilledema due to idiopathic intracranial hypertension. 2 normal fellow eyes of patients with buried ONHD were included. Methods A raster scan on the optic nerve and retinal nerve fiber layer (RNFL) thickness analysis was performed on each eye using SD-OCT. Eight eyes underwent enhanced depth imaging SD-OCT. Images were assessed qualitatively and quantitatively to identify differentiating features between buried ONHD and papilledema. Five clinicians trained with a tutorial and masked to the underlying diagnosis reviewed the SD-OCT images of each eye independently to determine the diagnosis. Main outcome measures Differences in RNFL thickness in each quadrant between the two groups, and diagnostic accuracy of five independent clinicians based on the SD-OCT images alone. Results We found no statistically significant difference in RNFL thickness between buried ONHD and papilledema in any of the four quadrants. Diagnostic accuracy among the readers was low and ranged from 50–64%. The kappa coefficient of agreement among the readers was 0.35 (95% Confidence interval: 0.19, 0.54). Conclusions SD-OCT is not clinically reliable in differentiating buried ONHD and mild papilledema. PMID:24321144

  20. Repeatability and reproducibility of optic nerve head perfusion measurements using optical coherence tomography angiography

    Science.gov (United States)

    Chen, Chieh-Li; Bojikian, Karine D.; Xin, Chen; Wen, Joanne C.; Gupta, Divakar; Zhang, Qinqin; Mudumbai, Raghu C.; Johnstone, Murray A.; Chen, Philip P.; Wang, Ruikang K.

    2016-06-01

    Optical coherence tomography angiography (OCTA) has increasingly become a clinically useful technique in ophthalmic imaging. We evaluate the repeatability and reproducibility of blood perfusion in the optic nerve head (ONH) measured using optical microangiography (OMAG)-based OCTA. Ten eyes from 10 healthy volunteers are recruited and scanned three times with a 68-kHz Cirrus HD-OCT 5000-based OMAG prototype system (Carl Zeiss Meditec Inc., Dublin, California) centered at the ONH involving two separate visits within six weeks. Vascular images are generated with OMAG processing by detecting the differences in OCT signals between consecutive B-scans acquired at the same retina location. ONH perfusion is quantified as flux, vessel area density, and normalized flux within the ONH for the prelaminar, lamina cribrosa, and the full ONH. Coefficient of variation (CV) and intraclass correlation coefficient (ICC) are used to evaluate intravisit and intervisit repeatability, and interobserver reproducibility. ONH perfusion measurements show high repeatability [CV≤3.7% (intravisit) and ≤5.2% (intervisit)] and interobserver reproducibility (ICC≤0.966) in all three layers by three metrics. OCTA provides a noninvasive method to visualize and quantify ONH perfusion in human eyes with excellent repeatability and reproducibility, which may add additional insight into ONH perfusion in clinical practice.

  1. Optical scattering coefficient estimated by optical coherence tomography correlates with collagen content in ovarian tissue

    Science.gov (United States)

    Yang, Yi; Wang, Tianheng; Biswal, Nrusingh C.; Wang, Xiaohong; Sanders, Melinda; Brewer, Molly; Zhu, Quing

    2011-09-01

    Optical scattering coefficient from ex vivo unfixed normal and malignant ovarian tissue was quantitatively extracted by fitting optical coherence tomography (OCT) A-line signals to a single scattering model. 1097 average A-line measurements at a wavelength of 1310 nm were performed at 108 sites obtained from 18 ovaries. The average scattering coefficient obtained from the normal tissue group consisted of 833 measurements from 88 sites was 2.41 mm-1 (+/-0.59), while the average coefficient obtained from the malignant tissue group consisted of 264 measurements from 20 sites was 1.55 mm-1 (+/-0.46). The malignant ovarian tissue showed significant lower scattering than the normal group (p collagen within OCT imaging depth was analyzed from the tissue histological section stained with Sirius Red. The average collagen area fraction (CAF) obtained from the normal tissue group was 48.4% (+/-12.3%), while the average CAF obtained from the malignant tissue group was 11.4% (+/-4.7%). A statistical significance of the collagen content was found between the two groups (p < 0.001). These results demonstrated that quantitative measurements of optical scattering coefficient from OCT images could be a potential powerful method for ovarian cancer detection.

  2. Optical imaging of oral pathological tissue using optical coherence tomography and synchrotron radiation computed microtomography

    Science.gov (United States)

    Cânjǎu, Silvana; Todea, Carmen; Sinescu, Cosmin; Negrutiu, Meda L.; Duma, Virgil; Mǎnescu, Adrian; Topalǎ, Florin I.; Podoleanu, Adrian Gh.

    2013-06-01

    The efforts aimed at early diagnosis of oral cancer should be prioritized towards developing a new screening instrument, based on optical coherence tomography (OCT), to be used directly intraorally, able to perform a fast, real time, 3D and non-invasive diagnosis of oral malignancies. The first step in this direction would be to optimize the OCT image interpretation of oral tissues. Therefore we propose plastination as a tissue preparation method that better preserves three-dimensional structure for study by new optical imaging techniques. The OCT and the synchrotron radiation computed microtomography (micro-CT) were employed for tissue sample analyze. For validating the OCT results we used the gold standard diagnostic procedure for any suspicious lesion - histopathology. This is a preliminary study of comparing features provided by OCT and Micro-CT. In the conditions of the present study, OCT proves to be a highly promising imaging modality. The use of x-ray based topographic imaging of small biological samples has been limited by the low intrinsic x-ray absorption of non-mineralized tissue and the lack of established contrast agents. Plastination can be used to enhance optical imagies of oral soft tissue samples.

  3. Study of optical properties and proteoglycan content of tendons by polarization sensitive optical coherence tomography

    Science.gov (United States)

    Yang, Ying; Rupani, Asha; Bagnaninchi, Pierre; Wimpenny, Ian; Weightman, Alan

    2012-08-01

    The highly orientated collagen fibers in tendons play a critical role for transferring tensile stress, and they demonstrate birefringent optical properties. However, the influence that proteoglycans (PGs) have on the optical properties of tendons is yet to be fully elucidated. PGs are the essential components of the tendon extracellular matrix; the changes in their quantities and compositions have been associated with tendinopathies. In this study, polarization sensitive optical coherence tomography (PS-OCT) has been used to reveal the relationship between PG content/location and birefringence properties of tendons. Fresh chicken tendons were imaged at regular intervals by PS-OCT and polarization light microscopy during the extraction of PGs, using guanidine hydrochloride (GuHCl). Complementary time-lapsed images taken from the two modalities mutually demonstrated that the extraction of PGs disturbed the local organization of collagen bundles. This corresponded with a decrease in birefringence and associated banding pattern observed by PS-OCT. Furthermore, this study revealed there was a higher concentration of PGs in the outer sheath region than in the fascicles, and therefore the change in birefringence was reduced when extraction was performed on unsheathed tendons. The results provide new insights of tendon structure and the role of PGs on the structural stability of tendons, which also demonstrates the great potential for using PS-OCT as a diagnostic tool to examine tendon pathology.

  4. Optical coherence tomography: technology and applications (biological and medical physics, biomedical engineering)

    CERN Document Server

    2013-01-01

    Optical coherence tomography (OCT) is the optical analog of ultrasound imaging and is emerging as a powerful imaging technique that enables non-invasive, in vivo, high resolution, cross-sectional imaging in biological tissue. This book introduces OCT technology and applications not only from an optical and technological viewpoint, but also from biomedical and clinical perspectives. The chapters are written by leading research groups, in a style comprehensible to a broad audience.

  5. Structural examination of easel paintings with optical coherence tomography.

    Science.gov (United States)

    Targowski, Piotr; Iwanicka, Magdalena; Tymińska-Widmer, Ludmiła; Sylwestrzak, Marcin; Kwiatkowska, Ewa A

    2010-06-15

    Identification of the order, thickness, composition, and possibly the origin of the paint layers forming the structure of a painting, that is, its stratigraphy, is important in confirming its attribution and history as well as planning conservation treatments. The most common method of examination is analysis of a sample collected from the art object, both visually with a microscope and instrumentally through a variety of sophisticated, modern analytical tools. Because of its invasiveness, however, sampling is less than ideally compatible with conservation ethics; it is severely restricted with respect to the amount of material extirpated from the artwork. Sampling is also rather limited in that it provides only very local information. There is, therefore, a great need for a noninvasive method with sufficient in-depth resolution for resolving the stratigraphy of works of art. Optical coherence tomography (OCT) is a noninvasive, noncontact method of optical sectioning of partially transparent objects, with micrometer-level axial resolution. The method utilizes near-infrared light of low intensity (a few milliwatts) to obtain cross-sectional images of various objects; it has been mostly used in medical diagnostics. Through the serial collection of many such images, volume information may be extracted. The application of OCT to the examination of art objects has been in development since 2003. In this Account, we present a short introduction to the technique, briefly discuss the apparatus we use, and provide a paradigm for reading OCT tomograms. Unlike the majority of papers published previously, this Account focuses on one, very specific, use of OCT. We then consider two examples of successful, practical application of the technique. At the request of a conservation studio, the characteristics of inscriptions on two oil paintings, originating from the 18th and 19th centuries, were analyzed. In the first case, it was possible to resolve some questions concerning the

  6. Computational adaptive optics for broadband interferometric tomography of tissues and cells

    Science.gov (United States)

    Adie, Steven G.; Mulligan, Jeffrey A.

    2016-03-01

    Adaptive optics (AO) can shape aberrated optical wavefronts to physically restore the constructive interference needed for high-resolution imaging. With access to the complex optical field, however, many functions of optical hardware can be achieved computationally, including focusing and the compensation of optical aberrations to restore the constructive interference required for diffraction-limited imaging performance. Holography, which employs interferometric detection of the complex optical field, was developed based on this connection between hardware and computational image formation, although this link has only recently been exploited for 3D tomographic imaging in scattering biological tissues. This talk will present the underlying imaging science behind computational image formation with optical coherence tomography (OCT) -- a beam-scanned version of broadband digital holography. Analogous to hardware AO (HAO), we demonstrate computational adaptive optics (CAO) and optimization of the computed pupil correction in 'sensorless mode' (Zernike polynomial corrections with feedback from image metrics) or with the use of 'guide-stars' in the sample. We discuss the concept of an 'isotomic volume' as the volumetric extension of the 'isoplanatic patch' introduced in astronomical AO. Recent CAO results and ongoing work is highlighted to point to the potential biomedical impact of computed broadband interferometric tomography. We also discuss the advantages and disadvantages of HAO vs. CAO for the effective shaping of optical wavefronts, and highlight opportunities for hybrid approaches that synergistically combine the unique advantages of hardware and computational methods for rapid volumetric tomography with cellular resolution.

  7. Optic nerve head analysis of superior segmental optic hypoplasia using Heidelberg retina tomography

    Directory of Open Access Journals (Sweden)

    Atsushi Miki

    2010-10-01

    , especially in the nasal superior sector. Approximately half of the eyes with SSOH were classified as abnormal using indices developed for detecting glaucoma, but the sectorial analysis revealed that the affected sectors were different from those of glaucoma. Optic nerve head measurements using the HRT may be useful in evaluating the optic disc characteristics in eyes with SSOH.Keywords: superior segmental optic hypoplasia, Heidelberg retina tomography

  8. Functional imaging in bulk tissue specimens using optical emission tomography: fluorescence preservation during optical clearing

    Science.gov (United States)

    Sakhalkar, H. S.; Dewhirst, M.; Oliver, T.; Cao, Y.; Oldham, M.

    2007-04-01

    Optical emission computed tomography (optical-ECT) is a technique for imaging the three-dimensional (3D) distribution of fluorescent probes in biological tissue specimens with high contrast and spatial resolution. In optical-ECT, functional information can be imaged by (i) systemic application of functional labels (e.g. fluorophore labelled proteins) and/or (ii) endogenous expression of fluorescent reporter proteins (e.g. red fluorescent protein (RFP), green fluorescent protein (GFP)) in vivo. An essential prerequisite for optical-ECT is optical clearing, a procedure where tissue specimens are made transparent to light by sequential perfusion with fixing, dehydrating and clearing agents. In this study, we investigate clearing protocols involving a selection of common fixing (4% buffered paraformaldehyde (PFA), methanol and ethanol), dehydrating (methanol and ethanol) and clearing agents (methyl salicylate and benzyl-alcohol-benzyl-benzoate (BABB)) in order to determine a 'fluorescence friendly' clearing procedure. Cell culture experiments were employed to optimize the sequence of chemical treatments that best preserve fluorescence. Texas red (TxRed), fluorescein isothiocyanate (FITC), RFP and GFP were tested as fluorophores and fluorescent reporter proteins of interest. Fluorescent and control cells were imaged on a microscope using a DSred2 and FITC filter set. The most promising clearing protocols of cell culture experiments were applied to whole xenograft tumour specimens, to test their effectiveness in large unsectioned samples. Fluorescence of TxRed/FITC fluorophores was not found to be significantly affected by any of the test clearing protocols. RFP and GFP fluorescence, however, was found to be significantly greater when cell fixation was in ethanol. Fixation in either PFA or methanol resulted in diminished fluorescence. After ethanol fixation, the RFP and GFP fluorescence proved remarkably robust to subsequent exposure to either methyl salicylate or BABB

  9. Inner structure detection by optical tomography technology based on feedback of microchip Nd:YAG lasers.

    Science.gov (United States)

    Xu, Chunxin; Zhang, Shulian; Tan, Yidong; Zhao, Shijie

    2013-05-20

    We describe a new optical tomography technology based on feedback of microchip Nd:YAG lasers. In the case of feedback light frequency-shifted, light can be magnified by a fact of 10(6) in the Nd:YAG microchip lasers, which makes it possible to realize optical tomography with a greater depth than current optical tomography. The results of the measuring and imaging of kinds of samples are presented, which demonstrate the feasibility and potential of this approach in the inner structure detection. The system has a lateral resolution of ~1 μm, a vertical resolution of 15 μm and a longitudinal scanning range of over 10mm.

  10. The employment of optic coherence tomography in the diagnosis of papilledema

    Directory of Open Access Journals (Sweden)

    Yaney González Yglesias

    2009-11-01

    Full Text Available Background: The optic coherence tomography constitute one of the most revolucionary tool in the ophtalmic diagnosis in the latest years, and is very useful in the papilledema studies. Objectives: Evaluate the optic coherence tomography useful in papilledema diagnosis. Methods: Prospective, observacional and analytic study made since may to october 2007 in the neuroophtalmology deparment, Ophtalmology Cuban Institute “ Ramón Pando ferrer”. Were studied 27 patients that presented a typical papilledema in the first episode at least with 2 months of duration. Results: The female sex was predominant with 27 of medium age. The medium thickness values of nervous fiber layer were stadistic important betwen the sectors (p=0.000. The nervous fiber layer thickness was predominant in order to frequency in lower, upper, nasal and temporal sectors. Conclusions: The optic coherence tomography constitute an useful instrument to papilledema diagnosis.

  11. Imaging actinic keratosis by high-definition optical coherence tomography. Histomorphologic correlation

    DEFF Research Database (Denmark)

    Boone, Marc A L M; Norrenberg, Sarah; Jemec, Gregor B E;

    2013-01-01

    transversal and axial directions, enable to visualize individual cells up to a depth of around 570 μm filling the imaging gap between conventional optical coherence tomography and reflectance confocal microscopy. We sought to determine the feasibility of detecting and grading of actinic keratosis...... by this technique using criteria defined for reflectance confocal microscopy compared to histology. In this pilot study, skin lesions of 17 patients with a histologically proven actinic keratosis were imaged by high-definition optical coherence tomography just before excision and images analysed qualitatively...... of photodamage. Using features already suggested by reflectance confocal microscopy, the study implies that high-definition optical coherence tomography facilitates in vivo diagnosis of actinic keratosis and allows the grading of different actinic keratosis lesions for increased clinical utility....

  12. Comparison of optical coherence tomography, microcomputed tomography, and histology at a three-dimensionally imaged trabecular bone sample

    Science.gov (United States)

    Kasseck, Christoph; Kratz, Marita; Torcasio, Antonia; Gerhardt, Nils C.; van Lenthe, G. Harry; Gambichler, Thilo; Hoffmann, Klaus; Jones, David B.; Hofmann, Martin R.

    2010-07-01

    We investigate optical coherence tomography (OCT) as a method for imaging bone. The OCT images are compared directly to those of the standard methods of bone histology and microcomputed tomography (μCT) on a single, fixed human femoral trabecular bone sample. An advantage of OCT over bone histology is its noninvasive nature. OCT also images the lamellar structure of trabeculae at slightly higher contrast than normal bone histology. While μCT visualizes the trabecular framework of the whole sample, OCT can image additionally cells with a penetration depth limited approximately to 1 mm. The most significant advantage of OCT, however, is the absence of toxic effects (no ionizing radiation), i.e., continuous images may be made and individual cell tracking may be performed. The penetration depth of OCT, however, limits its use to small animal models and small bone organ cultures.

  13. Time-Gated Optical Projection Tomography Allows Visualization of Adult Zebrafish Internal Structures

    Science.gov (United States)

    Foglia, Efrem Alessandro; Pistocchi, Anna; D'Andrea, Cosimo; Valentini, Gianluca; Cubeddu, Rinaldo; De Silvestri, Sandro; Cerullo, Giulio; Cotelli, Franco

    2012-01-01

    Optical imaging through biological samples is compromised by tissue scattering and currently various approaches aim to overcome this limitation. In this paper we demonstrate that an all optical technique, based on non-linear upconversion of infrared ultrashort laser pulses and on multiple view acquisition, allows the reduction of scattering effects in tomographic imaging. This technique, namely Time-Gated Optical Projection Tomography (TGOPT), is used to reconstruct three dimensionally the internal structure of adult zebrafish without staining or clearing agents. This method extends the use of Optical Projection Tomography to optically diffusive samples yielding reconstructions with reduced artifacts, increased contrast and improved resolution with respect to those obtained with non-gated techniques. The paper shows that TGOPT is particularly suited for imaging the skeletal system and nervous structures of adult zebrafish. PMID:23185643

  14. Current and future potential of retinal optical coherence tomography in multiple sclerosis with and without optic neuritis.

    Science.gov (United States)

    Balk, Lisanne J; Petzold, Axel

    2014-01-01

    Multiple sclerosis (MS) is a disorder characterized by inflammation and neuroaxonal degeneration. The latter is held responsible for the irreversible disability in patients with MS. The eye is a unique window into the brain. With the advent of optical coherence tomography, accurate quantification of retinal layer thickness has become feasible. Neuroaxonal degeneration affecting the retinal layers is structurally and functionally related to pathology in the visual pathways, which is most severe following MS optic neuritis. This is relevant to recognize because MS optic neuritis may mask the subtle thinning of retinal layers associated with global CNS atrophy, which is also related to more global loss of neurological function. Taken together, optical coherence tomography stands at the brink of becoming a validated imaging biomarker for monitoring neurodegeneration in MS and to provide end points for clinical trials.

  15. Fingerprint imaging from the inside of a finger with full-field optical coherence tomography

    Science.gov (United States)

    Auksorius, Egidijus; Boccara, A. Claude

    2015-01-01

    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 purposes. PMID:26601009

  16. Reconstruction methods for sound visualization based on acousto-optic tomography

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Lylloff, Oliver; Barrera Figueroa, Salvador;

    2013-01-01

    The visualization of acoustic fields using acousto-optic tomography has recently proved to yield satisfactory results in the audible frequency range. The current implementation of this visualization technique uses a laser Doppler vibrometer (LDV) to measure the acousto-optic effect, that is...... tomographic techniques. The filtered back projection (FBP) method is the most popular reconstruction algorithm used for tomography in many fields of science. The present study takes the performance of the FBP method in sound visualization as a reference and investigates the use of alternative methods commonly...

  17. Integrated optical coherence tomography and optical coherence microscopy imaging of human pathology

    Science.gov (United States)

    Lee, Hsiang-Chieh; Zhou, Chao; Wang, Yihong; Aquirre, Aaron D.; Tsai, Tsung-Han; Cohen, David W.; Connolly, James L.; Fujimoto, James G.

    2010-02-01

    Excisional biopsy is the current gold standard for disease diagnosis; however, it requires a relatively long processing time and it may also suffer from unacceptable false negative rates due to sampling errors. Optical coherence tomography (OCT) is a promising imaging technique that provide real-time, high resolution and three-dimensional (3D) images of tissue morphology. Optical coherence microscopy (OCM) is an extension of OCT, combining both the coherence gating and the confocal gating techniques. OCM imaging achieves cellular resolution with deeper imaging depth compared to confocal microscopy. An integrated OCT/OCM imaging system can provide co-registered multiscale imaging of tissue morphology. 3D-OCT provides architectural information with a large field of view and can be used to find regions of interest; while OCM provides high magnification to enable cellular imaging. The integrated OCT/OCM system has an axial resolution of kidney (19), were imaged with OCT and OCM within 2 to 6 hours after excision. The images were compared with H & E histology to identify characteristic features useful for disease diagnosis. The feasibility of visualizing human pathology using integrated OCT/OCM was demonstrated in the pathology laboratory settings.

  18. Optical probe design with extended depth-of-focus for optical coherence microscopy and optical coherence tomography

    Science.gov (United States)

    Lee, Seungwan; Choi, Minseog; Lee, Eunsung; Jung, Kyu-Dong; Chang, Jong-hyeon; Kim, Woonbae

    2013-03-01

    In this report, Optical probe system for modality, optical coherence tomography (OCT) and optical coherence microscope (OCM), is presented. In order to control the back focal length from 2.2 mm to 27 mm, optical probe is designed using two liquid lenses and several lenses. The narrow depth of focus (DOF) in microscope is extended by phase filter such as cubic filter. The filter is modified so that DOF is extended only In the OCM mode. The section for the extended DOF of probe is controlled by iris. Therefore in OCT mode, the phase filter does not affect on the DOF of lens. In OCM mode, the Gaussian light and modified light will affect the DOF. The probe dimension is less than 4 mm diameter and less than 60 mm long. The scan range of system is 0.88 mm wide, 1 mm deep in the OCT and 510 μm wide, 1 mm deep in the OCM mode. The lens curvature and iris aperture are operated by digital microelectrofluidic lens and iris.

  19. Optical coherence tomography in papilledema and pseudopapilledema with and without optic nerve head drusen

    Directory of Open Access Journals (Sweden)

    Shikha Talwar Bassi

    2014-01-01

    Full Text Available Aim: To compare the spectral domain optical coherence tomography (SD-OCT findings of the optic disc and the peripapillary retina of patients with a true papilledema and pseudopapilledema with and without optic nerve head drusen (ONHD. Study Design: Retrospective Case Control Study. Subjects and Methods: Peripapillary retinal nerve fiber layer (PPRNFL thickness as depicted by SD-OCT of 94 eyes of 66 patients with papilledema (30 eyes, pseudopapiledema (31 eyes, and normal controls (33 eyes was analyzed. The mean RNFL thickness, total retinal thickness (TRT at a superior and inferior edge of the disc and the quadrant wise topography of increased RNFL were compared in all three groups. Sensitivity, specificity, and area under the receiver operating characteristic curve (AROC were calculated for all the parameters. Results: The median RNFL thickness was 185.4 (129.5-349.3 μm, 122.3 (109-156.3 μm and 91.62 ± 7 μm in papilledema, pseudopapilledema, and controls, respectively. Papilledema group had thicker PPRNFL in all quadrants except temporal quadrant. TRT was thicker in papilledema and pseudopapilledema compared to controls. ONHD could be directly visualized as high reflective clumps in the sub-retinal space or the RNFL in 30 eyes. Increased RNFL thickness in all four quadrants was noted 43.3% in papilledema and 9.7% in pseudopapilledema. Normal RNFL thickness in all four quadrants was noted in 0% in papilledema and 32.3% in pseudopapilledema. Nasal RNFL had the highest AROC (0.792 indicating high diagnostic ability to differentiate papilledema from pseudopapilledema. Conclusion: SD-OCT can be used as a tool to differentiate between papilledema and pseudopapilledema.

  20. Design and implementation of an optical simulation environment for bioluminescent tomography studies

    Institute of Scientific and Technical Information of China (English)

    LI Hui; TIAN Jie; LUO Jie; L(U) Yujie; CONG Wenxiang; WANG Ge

    2007-01-01

    As a challenging task for bioluminescent tomography simulation, a virtual optical environment is needed to solve the forward problem accurately, that is, to achieve a high precision for bioluminescent signal synthesis on the external body surface of a small animal. The molecular optical simulation environment named MOSE is implemented using the C + + programming language and the OpenGL techniques, including a user-friendly interface with interactive tools facilitating users' operations. The accuracy of the virtual optical environment is verified by error analysis of mesh simplification and comparison between MOSE results and experimental data. This virtual optical environment is accurate, flexible and efficient to simulate the photon propagation in complicated tissues, which has a great potential to become a software platform for bioluminescent tomography studies and other molecular imaging applications.

  1. Mapping coherence in measurement via full quantum tomography of a hybrid optical detector

    CERN Document Server

    Zhang, Lijian; Datta, Animesh; Puentes, Graciana; Lundeen, Jeff S; Jin, Xian-Min; Smith, Brian J; Plenio, Martin B; Walmsley, Ian A

    2012-01-01

    Quantum states and measurements exhibit wave-like --- continuous, or particle-like --- discrete, character. Hybrid discrete-continuous photonic systems are key to investigating fundamental quantum phenomena, generating superpositions of macroscopic states, and form essential resources for quantum-enhanced applications, e.g. entanglement distillation and quantum computation, as well as highly efficient optical telecommunications. Realizing the full potential of these hybrid systems requires quantum-optical measurements sensitive to complementary observables such as field quadrature amplitude and photon number. However, a thorough understanding of the practical performance of an optical detector interpolating between these two regions is absent. Here, we report the implementation of full quantum detector tomography, enabling the characterization of the simultaneous wave and photon-number sensitivities of quantum-optical detectors. This yields the largest parametrization to-date in quantum tomography experiments...

  2. Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yidong, E-mail: yidongyang@med.miami.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 and Department of Radiation Oncology, University of Miami School of Medicine, Miami, Florida 33136 (United States); Wang, Ken Kang-Hsin; Wong, John W. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States); Eslami, Sohrab; Iordachita, Iulian I. [Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Patterson, Michael S. [Juravinski Cancer Centre and Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S4K1 (Canada)

    2015-04-15

    Purpose: The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides excellent bone to soft tissue contrast, but is incapable of differentiating tumors from surrounding soft tissue. Bioluminescence tomography (BLT), in contrast, allows direct visualization of even subpalpable tumors and quantitative evaluation of tumor response. Integration of BLT with CBCT offers complementary image information, with CBCT delineating anatomic structures and BLT differentiating luminescent tumors. This study is to develop a systematic method to calibrate an integrated CBCT and BLT imaging system which can be adopted onboard the SARRP to guide focal tumor irradiation. Methods: The integrated imaging system consists of CBCT, diffuse optical tomography (DOT), and BLT. The anatomy acquired from CBCT and optical properties acquired from DOT serve as a priori information for the subsequent BLT reconstruction. Phantoms were designed and procedures were developed to calibrate the CBCT, DOT/BLT, and the entire integrated system. Geometrical calibration was performed to calibrate the CBCT system. Flat field correction was performed to correct the nonuniform response of the optical imaging system. Absolute emittance calibration was performed to convert the camera readout to the emittance at the phantom or animal surface, which enabled the direct reconstruction of the bioluminescence source strength. Phantom and mouse imaging were performed to validate the calibration. Results: All calibration procedures were successfully performed. Both CBCT of a thin wire and a euthanized mouse revealed no spatial artifact, validating the accuracy of the CBCT calibration. The absolute emittance calibration was validated with a 650 nm laser source, resulting in a 3

  3. Long-wavelength optical coherence tomography at 1.7 µm for enhanced imaging depth

    OpenAIRE

    Sharma, Utkarsh; Chang, Ernest W.; Seok H Yun

    2008-01-01

    Multiple scattering in a sample presents a significant limitation to achieve meaningful structural information at deeper penetration depths in optical coherence tomography (OCT). Previous studies suggest that the spectral region around 1.7 µm may exhibit reduced scattering coefficients in biological tissues compared to the widely used wavelengths around 1.3 µm. To investigate this long-wavelength region, we developed a wavelength-swept laser at 1.7 µm wavelength and conducted OCT or optical f...

  4. Two-dimensional optical tomography of hemodynamic changes in a preterm infant brain

    Institute of Scientific and Technical Information of China (English)

    Feng Gao; Yuan Xue; Huijuan Zhao; Takashi Kusaka; Masanori Ueno; Yukio Yamada

    2007-01-01

    Our preliminary results on two-dimensional (2D) optical tomographic imaging of hemodynamic changes in a preterm infant brain are reported. We use the established 16-channel time-correlated single photon counting system for the detection and generalized pulse spectrum technique based algorithm for the image reconstruction. The experiments demonstrate that diffuse optical tomography may be a potent means for investigating brain functions and neural development of infant brains in the perinatal period.

  5. Magnetic induction tomography using an all-optical ⁸⁷Rb atomic magnetometer.

    Science.gov (United States)

    Wickenbrock, Arne; Jurgilas, Sarunas; Dow, Albert; Marmugi, Luca; Renzoni, Ferruccio

    2014-11-15

    We demonstrate magnetic induction tomography (MIT) with an all-optical atomic magnetometer. Our instrument creates a conductivity map of conductive objects. Both the shape and size of the imaged samples compare very well with the actual shape and size. Given the potential of all-optical atomic magnetometers for miniaturization and extreme sensitivity, the proof-of-principle presented in this Letter opens up promising avenues in the development of instrumentation for MIT.

  6. Two-dimensional optical tomography of hemodynamic changes in a preterm infant brain

    Science.gov (United States)

    Gao, Feng; Xue, Yuan; Zhao, Huijuan; Kusaka, Takashi; Ueno, Masanori; Yamada, Yukio

    2007-08-01

    Our preliminary results on two-dimensional (2D) optical tomographic imaging of hemodynamic changes in a preterm infant brain are reported. We use the established 16-channel time-correlated single photon counting system for the detection and generalized pulse spectrum technique based algorithm for the image reconstruction. The experiments demonstrate that diffuse optical tomography may be a potent means for investigating brain functions and neural development of infant brains in the perinatal period.

  7. Design and testing of prototype handheld scanning probes for optical coherence tomography.

    Science.gov (United States)

    Demian, Dorin; Duma, Virgil-Florin; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Cernat, Ramona; Topala, Florin Ionel; Hutiu, Gheorghe; Bradu, Adrian; Podoleanu, Adrian Gh

    2014-08-01

    Three simple and low-cost configurations of handheld scanning probes for optical coherence tomography have been developed. Their design and testing for dentistry applications are presented. The first two configurations were built exclusively from available off-the-shelf optomechanical components, which, to the best of our knowledge, are the first designs of this type. The third configuration includes these components in an optimized and ergonomic probe. All the designs are presented in detail to allow for their duplication in any laboratory with a minimum effort, for applications that range from educational to high-end clinical investigations. Requirements that have to be fulfilled to achieve configurations which are reliable, ergonomic-for clinical environments, and easy to build are presented. While a range of applications is possible for the prototypes developed, in this study the handheld probes are tested ex vivo with a spectral domain optical coherence tomography system built in-house, for dental constructs. A previous testing with a swept source optical coherence tomography system has also been performed both in vivo and ex vivo for ear, nose, and throat-in a medical environment. The applications use the capability of optical coherence tomography to achieve real-time, high-resolution, non-contact, and non-destructive interferometric investigations with micrometer resolutions and millimeter penetration depth inside the sample. In this study, testing the quality of the material of one of the most used types of dental prosthesis, metalo-ceramic is thus demonstrated.

  8. The amplitude and the phase or: Measuring directional and random motion with optical coherence tomography

    NARCIS (Netherlands)

    Weiss, N.M.

    2016-01-01

    Optical coherence tomography (OCT) uses a low coherence light source and a Michelson interferometer to measure path-length resolved backscatter profiles of samples with micrometer resolution and up to a few millimeters long. The OCT amplitude is typically used to generate images of the sample. Addit

  9. Imaging of basal cell carcinoma by high-definition optical coherence tomography

    DEFF Research Database (Denmark)

    Boone, M A L M; Norrenberg, S; Jemec, G B E;

    2012-01-01

    With the continued development of noninvasive therapies for basal cell carcinoma (BCC) such as photodynamic therapy and immune therapies, noninvasive diagnosis and monitoring become increasingly relevant. High-definition optical coherence tomography (HD-OCT) is a high-resolution imaging tool...

  10. Localized measurement of longitudinal and transverse flow velocities in colloidal suspensions using optical coherence tomography

    NARCIS (Netherlands)

    Weiss, N.; Van Leeuwen, T.G.; Kalkman, J.

    2013-01-01

    We report on localized measurement of the longitudinal and transverse flow velocities in a colloidal suspension using optical coherence tomography. We present a model for the path-length resolved autocorrelation function including diffusion and flow, which we experimentally verify. For flow that is

  11. Optical coherence tomography complemented by hyperspectral imaging for the study of protective wood coatings

    NARCIS (Netherlands)

    Dingemans, L.M.; Papadakis, V.; Liu, P.; Adam, A.J.L.; Groves, R.M.

    2015-01-01

    Optical coherence tomography (OCT) is a contactless and non-destructive testing (NDT) technique based on lowcoherence interferometry. It has recently become a popular NDT-tool for evaluating cultural heritage. In this study, protective coatings on wood and their penetration into the wood structure w

  12. Near-infrared optical coherence tomography for the inspection of fiber composites

    NARCIS (Netherlands)

    Liu, P.; Yao, L.; Groves, R.M.

    2015-01-01

    Optical coherence tomography (OCT) is a non-invasive imaging method, which allows the econstruction of three dimensional depth-resolved images with microscale resolution. Originally developed for biomedical diagnostics, nowadays it also shows a high potential for applications in the field of non-des

  13. Dimensional quality control of Ti-Ni dental file by optical coordinate metrology and computed tomography

    DEFF Research Database (Denmark)

    Yagüe-Fabra, J.A.; Tosello, Guido; Ontiveros, S.

    2014-01-01

    Endodontic dental files usually present complex 3D geometries, which make the complete measurement of the component very challenging with conventional micro metrology tools. Computed Tomography (CT) can represent a suitable alternative solution to micro metrology tools based on optical and tactil...

  14. Optical Coherence Tomography for the Assessment of Coronary Atherosclerosis and Vessel Response after Stent Implantation

    NARCIS (Netherlands)

    N. Gonzalo (Nieves)

    2010-01-01

    textabstractOptical Coherence Tomography (OCT) is a light-based imaging modality that can provide in vivo high-resolution images of the coronary artery with a level of resolution (axial 10-20 µm) ten times higher than intravascular ultrasound. The technique, uses low-coherent near infrarred light t

  15. In vivo Imaging of Sarcoptes scabiei Infestation Using Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Banzhaf, Christina Alette; Themstrup, Lotte; Ring, Hans Christian

    2013-01-01

    BACKGROUND: Sarcoptes scabiei can be visualized with different imaging tools. Optical coherence tomography (OCT) may have the potential to describe the changes in skin morphology due to scabies infestation and visualize the parasite. METHODS: Five patients from the Departments of Dermatology......, this technology could potentially allow rapid, non-invasive, in vivo diagnosis and analysis of infestations....

  16. Retrospective image-based gating of intracoronary optical coherence tomography: Implications for quantitative analysis

    NARCIS (Netherlands)

    K. Sihan (Kenji); C.P. Botha (Charl); F.H. Post (Frits); S. de Winter (Sebastiaan); N. Gonzalo (Nieves); E.S. Regar (Eveline); P.W.J.C. Serruys (Patrick); R. Hamers (Ronald); N. Bruining (Nico)

    2011-01-01

    textabstractAims: Images acquired of coronary vessels during a pullback of time-domain optical coherence tomography (OCT) are influenced by the dynamics of the heart. This study explores the feasibility of applying an in-house developed retrospective image-based gating method for OCT and the influen

  17. Combined Raman spectroscopy and optical coherence tomography device for tissue characterization

    NARCIS (Netherlands)

    Patil, Chetan A.; Bosschaart, Nienke; Keller, Matthew D.; Leeuwen, van Ton G.; Mahadevan-Jansen, Anita

    2008-01-01

    coherence tomography (OCT) along a common optical axis. The device enhances application of both RS and OCT by precisely guiding RS acquisition with OCT images while also compensating for the lack of molecular specificity in OCT with the biochemical specificity of RS. We characterize the system perfo

  18. Effect of optical coherence tomography (OCT) in assessing the prognosis of central serouschorioretinopathy

    Institute of Scientific and Technical Information of China (English)

    Lin Zhou; Yan Lu

    2015-01-01

    Objective:To study the effect of optical coherence tomography (OCT) in assessing the prognosis of central serouschorioretinopathy.Methods: 100 cases of central serous chorioretinopathy patients diagnosed in our hospital from 2013 May to 2014 May were enrolled in observation group and furtherly divided into neural epithelium detachment group, pigment epithelium detachment group, neural and pigment epithelium detachment group according to FFA. 100 cases health people received healthy examination in our hospital during the same period were enrolled in control group. Then optical coherence tomography and multifocal ERG results were compared.Results:(1) optical coherence tomography: Sfct, Nct, Sct, Tct, Ict of observation group were higher than those of control group; Sfct, Nct, Sct, Tct, Ict of neural and pigment epithelium detachment group were higher than those of neural epithelium detachment group and pigment epithelium detachment group; (2) multifocal ERG: 1ring and 2 ring of P1 wave reaction density of observation group were lower than those of control group; 3ring, 4 ring, 5 ring of P1 wave reaction density of observation group had no difference with control group.Conclusion:optical coherence tomography (OCT) can accurately assay choroidal thickness of central serouschorioretinopathy and has good consistency with fundus fluorescein angiography and multifocal ERG results.

  19. Early Swept-Source Optical Coherence Tomography Angiography Findings in Unilateral Acute Idiopathic Maculopathy.

    Science.gov (United States)

    Nicolo, Massimo; Rosa, Raffaella; Musetti, Donatella; Musolino, Maria; Traverso, Carlo Enrico

    2016-02-01

    Unilateral acute idiopathic maculopathy (UAIM) is a rare disorder presenting in young people with an acute onset of unilateral central visual loss often associated with a prodromal flu-like illness. The authors present the early anatomical findings of a 35-year-old man clinically diagnosed with UAIM using swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography.

  20. Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies

    DEFF Research Database (Denmark)

    Tearney, Guillermo J; Regar, Evelyn; Akasaka, Takashi

    2012-01-01

    The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the di...... the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease....

  1. Simultaneous dual wavelength eye-tracked ultrahigh resolution retinal and choroidal optical coherence tomography

    DEFF Research Database (Denmark)

    Unterhuber, A.; Povaay, B.; Müller, André;

    2013-01-01

    We demonstrate an optical coherence tomography device that simultaneously combines different novel ultrabroad bandwidth light sources centered in the 800 and 1060 nm regions, operating at 66 kHz depth scan rate, and a confocal laser scanning ophthalmoscope-based eye tracker to permit motion-artif...

  2. Complete Two-dimensional Muellermetric Imaging of Biological Tissue Using Heterodyned Optical Coherence Tomography

    CERN Document Server

    Liu, Xue; Shahriar, M S

    2010-01-01

    A polarization-sensitive optical coherence tomography system based on heterodyning and filtering techniques is built to perform Stokesmetric imaging of different layers of depths in a porcine tendon sample. The complete 4\\times4 backscattering Muellermetric images of one layer are acquired using such a system. The images reveal information indiscernible from a conventional OCT system.

  3. Clinical experiences with optical coherence tomography in epithelial (pre)malignancies

    NARCIS (Netherlands)

    Wessels, Ronni

    2015-01-01

    This thesis describes the potential of optical coherence tomography (OCT) to differentiate between normal tissue and (pre)malignant tissue in epithelial cancers. It can be divided in research performed in the genital area and the field of melanoma. Chapter 2 describes the principles of the OCT-tec

  4. The predictive value of optical coherence tomography after grid laser photocoagulation for diffuse diabetic macular oedema

    DEFF Research Database (Denmark)

    Soliman, W.; Sander, B.; Soliman, K.A.E.N.

    2008-01-01

    Purpose: To assess the predictive value of optical coherence tomography (OCT) mapping of retinal thickness and intraretinal morphological changes after macular grid for diffuse diabetic macular oedema (DMO). Methods: We carried out a prospective, non-controlled, case series study, in which 28 con...

  5. Measurement of biofilm growth and local hydrodynamics using optical coherence tomography

    NARCIS (Netherlands)

    Weiss, Nicolas; El Tayeb El Obied, Khalid; Kalkman, Jeroen; Lammertink, Rob G.H.; Leeuwen, van Ton G.

    2016-01-01

    We report on localized and simultaneous measurement of biofilm growth and local hydrodynamics in a microfluidic channel using optical coherence tomography. We measure independently with high spatio-temporal resolution the longitudinal flow velocity component parallel to the imaging beam and the tran

  6. Full wave model of image formation in optical coherence tomography applicable to general samples.

    Science.gov (United States)

    Munro, Peter R T; Curatolo, Andrea; Sampson, David D

    2015-02-09

    We demonstrate a highly realistic model of optical coherence tomography, based on an existing model of coherent optical microscopes, which employs a full wave description of light. A defining feature of the model is the decoupling of the key functions of an optical coherence tomography system: sample illumination, light-sample interaction and the collection of light scattered by the sample. We show how such a model can be implemented using the finite-difference time-domain method to model light propagation in general samples. The model employs vectorial focussing theory to represent the optical system and, thus, incorporates general illumination beam types and detection optics. To demonstrate its versatility, we model image formation of a stratified medium, a numerical point-spread function phantom and a numerical phantom, based upon a physical three-dimensional structured phantom employed in our laboratory. We show that simulated images compare well with experimental images of a three-dimensional structured phantom. Such a model provides a powerful means to advance all aspects of optical coherence tomography imaging.

  7. Imaging retinal nerve fiber bundles using optical coherence tomography with adaptive optics.

    Science.gov (United States)

    Kocaoglu, Omer P; Cense, Barry; Jonnal, Ravi S; Wang, Qiang; Lee, Sangyeol; Gao, Weihua; Miller, Donald T

    2011-08-15

    Early detection of axonal tissue loss in retinal nerve fiber layer (RNFL) is critical for effective treatment and management of diseases such as glaucoma. This study aims to evaluate the capability of ultrahigh-resolution optical coherence tomography with adaptive optics (UHR-AO-OCT) for imaging the RNFL axonal bundles (RNFBs) with 3×3×3μm(3) resolution in the eye. We used a research-grade UHR-AO-OCT system to acquire 3°×3° volumes in four normal subjects and one subject with an arcuate retinal nerve fiber layer defect (n=5; 29-62years). Cross section (B-scans) and en face (C-scan) slices extracted from the volumes were used to assess visibility and size distribution of individual RNFBs. In one subject, we reimaged the same RNFBs twice over a 7month interval and compared bundle width and thickness between the two imaging sessions. Lastly we compared images of an arcuate RNFL defect acquired with UHR-AO-OCT and commercial OCT (Heidelberg Spectralis). Individual RNFBs were distinguishable in all subjects at 3° retinal eccentricity in both cross-sectional and en face views (width: 30-50μm, thickness: 10-15μm). At 6° retinal eccentricity, RNFBs were distinguishable in three of the five subjects in both views (width: 30-45μm, thickness: 20-40μm). Width and thickness RNFB measurements taken 7months apart were strongly correlated (p<0.0005). Mean difference and standard deviation of the differences between the two measurement sessions were -0.1±4.0μm (width) and 0.3±1.5μm (thickness). UHR-AO-OCT outperformed commercial OCT in terms of clarity of the microscopic retina. To our knowledge, these are the first measurements of RNFB cross section reported in the living human eye.

  8. Imaging human retinal pigment epithelium cells using adaptive optics optical coherence tomography

    Science.gov (United States)

    Liu, Zhuolin; Kocaoglu, Omer P.; Turner, Timothy L.; Miller, Donald T.

    2016-03-01

    Retinal pigment epithelium (RPE) cells are vital to health of the outer retina, but are often compromised in ageing and major ocular diseases that lead to blindness. Early manifestation of RPE disruption occurs at the cellular level, and while biomarkers at this scale hold considerable promise, RPE cells have proven extremely challenging to image in the living human eye. We present a novel method based on optical coherence tomography (OCT) equipped with adaptive optics (AO) that overcomes the associated technical obstacles. The method takes advantage of the 3D resolution of AO-OCT, but more critically sub-cellular segmentation and registration that permit organelle motility to be used as a novel contrast mechanism. With this method, we successfully visualized RPE cells and characterized their 3D reflectance profile in every subject and retinal location (3° and 7° temporal to the fovea) imaged to date. We have quantified RPE packing geometry in terms of cell density, cone-to-RPE ratio, and number of nearest neighbors using Voronoi and power spectra analyses. RPE cell density (cells/mm2) showed no significant difference between 3° (4,892+/-691) and 7° (4,780+/-354). In contrast, cone-to- RPE ratio was significantly higher at 3° (3.88+/-0.52:1) than 7° (2.31+/- 0.23:1). Voronoi analysis also showed most RPE cells have six nearest neighbors, which was significantly larger than the next two most prevalent associations: five and seven. Averaged across the five subjects, prevalence of cells with six neighbors was 51.4+/-3.58% at 3°, and 54.58+/-3.01% at 7°. These results are consistent with histology and in vivo studies using other imaging modalities.

  9. Photons-based medical imaging - Radiology, X-ray tomography, gamma and positrons tomography, optical imaging; Imagerie medicale a base de photons - Radiologie, tomographie X, tomographie gamma et positons, imagerie optique

    Energy Technology Data Exchange (ETDEWEB)

    Fanet, H.; Dinten, J.M.; Moy, J.P.; Rinkel, J. [CEA Leti, Grenoble (France); Buvat, I. [IMNC - CNRS, Orsay (France); Da Silva, A. [Institut Fresnel, Marseille (France); Douek, P.; Peyrin, F. [INSA Lyon, Lyon Univ. (France); Frija, G. [Hopital Europeen George Pompidou, Paris (France); Trebossen, R. [CEA-Service hospitalier Frederic Joliot, Orsay (France)

    2010-07-01

    This book describes the different principles used in medical imaging. The detection aspects, the processing electronics and algorithms are detailed for the different techniques. This first tome analyses the photons-based techniques (X-rays, gamma rays and visible light). Content: 1 - physical background: radiation-matter interaction, consequences on detection and medical imaging; 2 - detectors for medical imaging; 3 - processing of numerical radiography images for quantization; 4 - X-ray tomography; 5 - positrons emission tomography: principles and applications; 6 - mono-photonic imaging; 7 - optical imaging; Index. (J.S.)

  10. Test target for characterizing 3D resolution of optical coherence tomography

    Science.gov (United States)

    Hu, Zhixiong; Hao, Bingtao; Liu, Wenli; Hong, Baoyu; Li, Jiao

    2014-12-01

    Optical coherence tomography (OCT) is a non-invasive 3D imaging technology which has been applied or investigated in many diagnostic fields including ophthalmology, dermatology, dentistry, cardiovasology, endoscopy, brain imaging and so on. Optical resolution is an important characteristic that can describe the quality and utility of an image acquiring system. We employ 3D printing technology to design and fabricate a test target for characterizing 3D resolution of optical coherence tomography. The test target which mimics USAF 1951 test chart was produced with photopolymer. By measuring the 3D test target, axial resolution as well as lateral resolution of a spectral domain OCT system was evaluated. For comparison, conventional microscope and surface profiler were employed to characterize the 3D test targets. The results demonstrate that the 3D resolution test targets have the potential of qualitatively and quantitatively validating the performance of OCT systems.

  11. Image reconstruction using wavelet multi-resolution technique for time-domain diffuse optical tomography

    Science.gov (United States)

    Yang, Fang; Gao, Feng; Jiao, Yuting; Zhao, Huijuan

    2010-02-01

    It is generally believed that the inverse problem in diffuse optical tomography (DOT) is highly ill-posed and its solution is always under-determined and sensitive to noise, which is the main problem in the application of DOT. In this paper, we propose a method on image reconstruction for time-domain diffuse optical tomography based on panel detection and Finite-Difference Method, and introduce an approach to reduce the number of unknown parameters in the reconstruction process. We propose a multi-level scheme to reduce the number of unknowns by parameterizing the spatial distribution of optical properties via wavelet transform and then reconstruct the coefficients of this transform. Compared with previous traditional uni-level full spatial domain algorithm, this method can efficiently improve the reconstruction quality. Numerical simulations show that wavelet-based multi-level inversion is superior to the uni-level algebraic reconstruction technique.

  12. In vitro birefringence imaging with spectral domain polarization-sensitive optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    Qiang Gong; Chuanmao Fan; Fan Zhang; Jianquan Yao

    2008-01-01

    Spectral domain polarization-sensitive optical coherence tomography (SDPS-OCT) is a depth-resolved polarization-sensitive interferometry which integrates polarization optics into spectral domain optical co-herence tomography (SD-OCT). This configuration can obtain birefringence information of samples and improve the imaging speed. In this paper, horizontally polarized light is used to replace natural light of the source. Then, right-rotated circularly polarized light is the incident sample light. To obtain two orthogonal components of the polarized interferogram, the reflected light of the reference arm is set to be 45° linearly polarized light. These two components are acquired by two spectrometers synchronously. The system was employed to achieve 12.8-#m axial resolution and 4.36-#m transverse resolution. We have imaged in vitro chicken tendon and muscle tissues with these system.

  13. Comparative study of iterative reconstruction algorithms for missing cone problems in optical diffraction tomography.

    Science.gov (United States)

    Lim, JooWon; Lee, KyeoReh; Jin, Kyong Hwan; Shin, Seungwoo; Lee, SeoEun; Park, YongKeun; Ye, Jong Chul

    2015-06-29

    In optical tomography, there exist certain spatial frequency components that cannot be measured due to the limited projection angles imposed by the numerical aperture of objective lenses. This limitation, often called as the missing cone problem, causes the under-estimation of refractive index (RI) values in tomograms and results in severe elongations of RI distributions along the optical axis. To address this missing cone problem, several iterative reconstruction algorithms have been introduced exploiting prior knowledge such as positivity in RI differences or edges of samples. In this paper, various existing iterative reconstruction algorithms are systematically compared for mitigating the missing cone problem in optical diffraction tomography. In particular, three representative regularization schemes, edge preserving, total variation regularization, and the Gerchberg-Papoulis algorithm, were numerically and experimentally evaluated using spherical beads as well as real biological samples; human red blood cells and hepatocyte cells. Our work will provide important guidelines for choosing the appropriate regularization in ODT.

  14. Sagittal laser optical tomography for imaging of rheumatoid finger joints

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, Andreas H [Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027 (United States); Klose, Alexander D [Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027 (United States); Scheel, Alexander K [Department of Nephrology and Rheumatology, Georg-August University, Goettingen (Germany); Moa-Anderson, Bryte [Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027 (United States); Backhaus, Marina [Department of Rheumatology and Clinical Immunology, Charite University Hospital, Berlin (Germany); Netz, Uwe [Institute for Medical Physics and Laser Medicine, Free University of Berlin, Berlin (Germany); Beuthan, Juergen [Institute for Medical Physics and Laser Medicine, Free University of Berlin, Berlin (Germany)

    2004-04-07

    We present a novel optical tomographic imaging system that was designed to determine two-dimensional spatial distribution of optical properties in a sagittal plane through finger joints. The system incorporates a single laser diode and a single silicon photodetector into a scanning device that records spatially resolved light intensities as they are transmitted through a finger. These data are input to a model-based iterative image reconstruction (MOBIIR) scheme, which uses the equation of radiative transfer (ERT) as a forward model for light propagation through tissue. We have used this system to obtain tomographic images of six proximal interphalangeal finger joints from two patients with rheumatoid arthritis. The optical images were compared to clinical symptoms and ultrasound images.

  15. Direct Estimation of Optical Parameters From Photoacoustic Time Series in Quantitative Photoacoustic Tomography.

    Science.gov (United States)

    Pulkkinen, Aki; Cox, Ben T; Arridge, Simon R; Goh, Hwan; Kaipio, Jari P; Tarvainen, Tanja

    2016-11-01

    Estimation of optical absorption and scattering of a target is an inverse problem associated with quantitative photoacoustic tomography. Conventionally, the problem is expressed as two folded. First, images of initial pressure distribution created by absorption of a light pulse are formed based on acoustic boundary measurements. Then, the optical properties are determined based on these photoacoustic images. The optical stage of the inverse problem can thus suffer from, for example, artefacts caused by the acoustic stage. These could be caused by imperfections in the acoustic measurement setting, of which an example is a limited view acoustic measurement geometry. In this work, the forward model of quantitative photoacoustic tomography is treated as a coupled acoustic and optical model and the inverse problem is solved by using a Bayesian approach. Spatial distribution of the optical properties of the imaged target are estimated directly from the photoacoustic time series in varying acoustic detection and optical illumination configurations. It is numerically demonstrated, that estimation of optical properties of the imaged target is feasible in limited view acoustic detection setting.

  16. Coherent broadband light source for parallel optical coherence tomography

    NARCIS (Netherlands)

    Rivier, S.; Laversenne, L.; Bourquin, S.; Salathé, R.P.; Pollnau, M.; Grivas, C.; Shepherd, D.P.; Eason, R.W.; Flury, M.; Philipoussis, I.; Herzig, H.P.

    2004-01-01

    A Ti:sapphire planar waveguide is rib structured by Ar ion milling to provide parallel channel waveguides. By coupling high-power pump light through a microlens array into the waveguides, a novel broadband luminescent parallel emitter is demonstrated as a light source for parallel optical coherence

  17. Optical Effects at projection measurements for Terahertz tomography

    Science.gov (United States)

    Brahm, A.; Wilms, A.; Tymoshchuk, M.; Grossmann, C.; Notni, G.; Tünnermann, A.

    2014-10-01

    Optical effects like refraction, diffraction and edge effects have an influence on Terahertz measurements. They can result in image artifacts which makes it difficult to detect and resolve material defects inside the samples. We used a geometrical optical ray tracing approach to analyze the optical effects at Terahertz projection measurements which can be used to perform 2D or 3D THz images. We measured rectangular and cylindrical samples made of PEEK (Polyetheretherketon), POM (Polyoxymethylen), and PMMA (Polymethylmethacrylat) and compared the results to simulations that are realized with the software ZEMAX. We were able to simulate the measured Fresnel refraction and transmission behavior for rectangular cuboids with a length of 25 mm and cylinders with diameter of 25 mm. We showed the influence of diffraction and edge effects at samples with different sizes made of PMMA. Thus, the optical effect of refraction was significant and observable for cylinders with diameters greater than 1.5 mm and holes with diameter greater than 2.5 mm.

  18. Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images

    Science.gov (United States)

    Minamino, Takuya; Mine, Atsushi; Matsumoto, Mariko; Sugawa, Yoshihiko; Kabetani, Tomoshige; Higashi, Mami; Kawaguchi, Asuka; Ohmi, Masato; Awazu, Kunio; Yatani, Hirofumi

    2015-10-01

    No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root.

  19. Laser Tomography Adaptive Optics (LTAO): A performance study

    CERN Document Server

    Tatulli, E

    2013-01-01

    We present an analytical derivation of the on-axis performance of Adaptive Optics systems using a given number of guide stars of arbitrary altitude, distributed at arbitrary angular positions in the sky. The expressions of the residual error are given for cases of both continuous and discrete turbulent atmospheric profiles. Assuming Shack-Hartmann wavefront sensing with circular apertures, we demonstrate that the error is formally described by integrals of products of three Bessel functions. We compare the performance of Adaptive Optics correction when using natural, Sodium or Rayleigh laser guide stars. For small diameter class telescopes (~5m), we show that a few number of Rayleigh beacons can provide similar performance to that of a single Sodium laser, for a lower overall cost of the instrument. For bigger apertures, using Rayleigh stars may not be such a suitable alternative because of the too severe cone effect that drastically degrades the quality of the correction.

  20. Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography.

    Science.gov (United States)

    Bennett, J L; de Seze, J; Lana-Peixoto, M; Palace, J; Waldman, A; Schippling, S; Tenembaum, S; Banwell, B; Greenberg, B; Levy, M; Fujihara, K; Chan, K H; Kim, H J; Asgari, N; Sato, D K; Saiz, A; Wuerfel, J; Zimmermann, H; Green, A; Villoslada, P; Paul, F

    2015-05-01

    Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients' RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies.

  1. Advanced Technologies for Structural and Functional Optical Coherence Tomography

    Science.gov (United States)

    2015-01-07

    bidirectional laser Doppler velocimetry (BLDV) combined with fundus photography is one of the most well suited methods for quantitative TRBF measurement...interventions or predict treatment outcomes. In another set of studies, we continued advancing the state of the art of the endoscopic OCT technology by...visualization by means of single-exposure speckle photography ," Optics Communications, vol. 37, pp. 326-330, 1981. [127] R. Bonner and R. Nossal, "Model for

  2. Tomography for multiconjugate adaptive optics systems using laser guide stars

    Science.gov (United States)

    Gavel, Donald T.

    2004-10-01

    In this paper we present a solution to the MCAO reconstruction problem using multiple laser guide stars and show that it can be interpreted as a form of back-projection tomography. It is shown that a key intermediate step is to determine a minimum-variance estimate of the index variations over the atmospheric volume. We follow the idea of Tokovinin and Viard [JOSA-A, April 2001] in initially formulating the problem in the Fourier domain; we then extend the interpretation to the spatial domain. The former results were limited to the case of infinite aperture and plane wave beacons, and the statistically optimal wavefront solution was given for a single science direction. The new approach is more general and interpretable as tomographic back-projections, which gives rise to algorithms for the finite aperture, cone (laser) beams, and wide-science-field cases. A fortuitous consequence of this analysis is that a "fast" algorithm suitable for real-time implementation has become evident. The reconstruction requires only filtering and the inversion of small (dimension = number of guidestars) matrices. In simulations, we compare results with those of a spatial domain least-square matrix-inversion method.

  3. Jones matrix analysis for a polarization-sensitive optical coherence tomography system using fiber-optic components

    Science.gov (United States)

    Hyle Park, B.; Pierce, Mark C.; Cense, Barry; de Boer, Johannes F.

    2004-11-01

    We present an analysis for polarization-sensitive optical coherence tomography that facilitates the unrestricted use of fiber and fiber-optic components throughout an interferometer and yields sample birefringence, diattenuation, and relative optic axis orientation. We use a novel Jones matrix approach that compares the polarization states of light reflected from the sample surface with those reflected from within a biological sample for pairs of depth scans. The incident polarization alternated between two states that are perpendicular in a Poincaré sphere representation to ensure proper detection of tissue birefringence regardless of optical fiber contributions. The method was validated by comparing the calculated diattenuation of a polarizing sheet, chicken tendon, and muscle with that obtained by independent measurement. The relative importance of diattenuation versus birefringence to angular displacement of Stokes vectors on a Poincaré sphere was quantified.

  4. Extraction of optical scattering parameters and attenuation compensation in optical coherence tomography images of multi-layered tissue structures

    DEFF Research Database (Denmark)

    Thrane, Lars; Frosz, Michael Henoch; Tycho, Andreas

    2004-01-01

    A recently developed analytical optical coherence tomography (OCT) model [Thrane et al., J. Opt. Soc. Am. A 17, 484 (2000)] allows the extraction of optical scattering parameters from OCT images, thereby permitting attenuation compensation in those images. By expanding this theoretical model, we...... have developed a new method for extracting optical scattering parameters from multilayered tissue structures in vivo. To verify this, we used a Monte Carlo (MC) OCT model as a numerical phantom to simulate the OCT signal for het-erogeneous multilayered tissue. Excellent agreement between the extracted...... values of the optical scattering properties of the different layers and the corresponding input reference values of the MC simulation was obtained, which demonstrates the feasibility of the method for in vivo applications. This is to our knowledge the first time such verification has been obtained...

  5. Optical design of an optical coherence tomography and multispectral fluorescence imaging endoscope to detect early stage ovarian cancer

    Science.gov (United States)

    Tate, Tyler; Keenan, Molly; Swan, Elizabeth; Black, John; Utzinger, Urs; Barton, Jennifer

    2014-12-01

    The five year survival rate for ovarian cancer is over 90% if early detection occurs, yet no effective early screening method exists. We have designed and are constructing a dual modality Optical Coherence Tomography (OCT) and Multispectral Fluorescence Imaging (MFI) endoscope to optically screen the Fallopian tube and ovary for early stage cancer. The endoscope reaches the ovary via the natural pathway of the vagina, cervix, uterus and Fallopian tube. In order to navigate the Fallopian tube the endoscope must have an outer diameter of 600 μm, be highly flexible, steerable, tracking and nonperforating. The imaging systems consists of six optical subsystems, two from OCT and four from MFI. The optical subsystems have independent and interrelated design criteria. The endoscope will be tested on realistic tissue models and ex vivo tissue to prove feasibility of future human trials. Ultimately the project aims to provide women the first effective ovarian cancer screening technique.

  6. Block matching 3D random noise filtering for absorption optical projection tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fumene Feruglio, P; Vinegoni, C; Weissleder, R [Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114 (United States); Gros, J [Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115 (United States); Sbarbati, A, E-mail: cvinegoni@mgh.harvard.ed [Department of Morphological and Biomedical Sciences, University of Verona, Strada Le Grazie 8, 37134 Verona (Italy)

    2010-09-21

    Absorption and emission optical projection tomography (OPT), alternatively referred to as optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT), are recently developed three-dimensional imaging techniques with value for developmental biology and ex vivo gene expression studies. The techniques' principles are similar to the ones used for x-ray computed tomography and are based on the approximation of negligible light scattering in optically cleared samples. The optical clearing is achieved by a chemical procedure which aims at substituting the cellular fluids within the sample with a cell membranes' index matching solution. Once cleared the sample presents very low scattering and is then illuminated with a light collimated beam whose intensity is captured in transillumination mode by a CCD camera. Different projection images of the sample are subsequently obtained over a 360{sup 0} full rotation, and a standard backprojection algorithm can be used in a similar fashion as for x-ray tomography in order to obtain absorption maps. Because not all biological samples present significant absorption contrast, it is not always possible to obtain projections with a good signal-to-noise ratio, a condition necessary to achieve high-quality tomographic reconstructions. Such is the case for example, for early stage's embryos. In this work we demonstrate how, through the use of a random noise removal algorithm, the image quality of the reconstructions can be considerably improved even when the noise is strongly present in the acquired projections. Specifically, we implemented a block matching 3D (BM3D) filter applying it separately on each acquired transillumination projection before performing a complete three-dimensional tomographical reconstruction. To test the efficiency of the adopted filtering scheme, a phantom and a real biological sample were processed. In both cases, the BM3D filter led to a signal-to-noise ratio

  7. Image reconstruction for optical tomography using photon density waves

    Science.gov (United States)

    Khalaf, Reem; van der Zee, Pieter; Dixon, Laurence C. W.; Davies, Alan

    1998-12-01

    The forward model in this work is based on the frequency- dependent diffusion approximation. The diffusion approximation is solved using the Finite Element Method with the Robin Boundary condition. The model is 2D, with a circular domain simulating the cross section of a limb. The meshes are generated with FIDAP, a computational fluid dynamics package. The diffusion matrix is solved using Cholesky decomposition, and results on the boundary for a modulated source include AC and DC data for a given set of optical parameters.

  8. Multiple Fan-Beam Optical Tomography: Modelling Techniques

    Directory of Open Access Journals (Sweden)

    Pang Jon Fea

    2009-10-01

    Full Text Available This paper explains in detail the solution to the forward and inverse problem faced in this research. In the forward problem section, the projection geometry and the sensor modelling are discussed. The dimensions, distributions and arrangements of the optical fibre sensors are determined based on the real hardware constructed and these are explained in the projection geometry section. The general idea in sensor modelling is to simulate an artificial environment, but with similar system properties, to predict the actual sensor values for various flow models in the hardware system. The sensitivity maps produced from the solution of the forward problems are important in reconstructing the tomographic image.

  9. Sound field reconstruction using acousto-optic tomography

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

    2012-01-01

    When sound propagates through a medium, it results in pressure fluctuations that change the instantaneous density of the medium. Under such circumstances, the refractive index that characterizes the propagation of light is not constant, but influenced by the acoustic field. This kind of interaction...... the acousto-optic effect in air, and demonstrates that it can be measured with a laser Doppler vibrometer in the audible frequency range. The tomographic reconstruction is tested by means of computer simulations and measurements. The main features observed in the simulations are also recognized...

  10. Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Bourezak, Rafik; Boulet, Benoit; Lamouche, Guy

    2010-08-01

    We present an innovative integration of an intravascular optical coherence tomography probe into a computerized balloon deployment system to monitor the balloon inflation process. The high-resolution intraluminal imaging of the balloon provides a detailed assessment of the balloon quality and, consequently, a technique to improve the balloon manufacturing process. A custom-built swept-source optical coherence tomography system is used for real-time imaging. A semicompliant balloon with a nominal diameter of 4 mm is fabricated for the experiments. Imaging results correspond to balloon deployment in air and inside an artery phantom. A characterization of the balloon diameter, wall thickness, compliance, and elastic modulus is provided, based on image segmentation. Using the images obtained from the probe pullback, a three-dimensional visualization of the inflated balloon is presented.

  11. New variational image decomposition model for simultaneously denoising and segmenting optical coherence tomography images.

    Science.gov (United States)

    Duan, Jinming; Tench, Christopher; Gottlob, Irene; Proudlock, Frank; Bai, Li

    2015-11-21

    Optical coherence tomography (OCT) imaging plays an important role in clinical diagnosis and monitoring of diseases of the human retina. Automated analysis of optical coherence tomography images is a challenging task as the images are inherently noisy. In this paper, a novel variational image decomposition model is proposed to decompose an OCT image into three components: the first component is the original image but with the noise completely removed; the second contains the set of edges representing the retinal layer boundaries present in the image; and the third is an image of noise, or in image decomposition terms, the texture, or oscillatory patterns of the original image. In addition, a fast Fourier transform based split Bregman algorithm is developed to improve computational efficiency of solving the proposed model. Extensive experiments are conducted on both synthesised and real OCT images to demonstrate that the proposed model outperforms the state-of-the-art speckle noise reduction methods and leads to accurate retinal layer segmentation.

  12. Theoretical limit of spatial resolution in diffuse optical tomography using a perturbation model

    Energy Technology Data Exchange (ETDEWEB)

    Konovalov, A B; Vlasov, V V [E.I. Zababakhin All-Russian Scientific-Research Institute of Technical Physics, Russian Federal Nuclear Centre, Snezhinsk, Chelyabinsk region (Russian Federation)

    2014-03-28

    We have assessed the limit of spatial resolution of timedomain diffuse optical tomography (DOT) based on a perturbation reconstruction model. From the viewpoint of the structure reconstruction accuracy, three different approaches to solving the inverse DOT problem are compared. The first approach involves reconstruction of diffuse tomograms from straight lines, the second – from average curvilinear trajectories of photons and the third – from total banana-shaped distributions of photon trajectories. In order to obtain estimates of resolution, we have derived analytical expressions for the point spread function and modulation transfer function, as well as have performed a numerical experiment on reconstruction of rectangular scattering objects with circular absorbing inhomogeneities. It is shown that in passing from reconstruction from straight lines to reconstruction using distributions of photon trajectories we can improve resolution by almost an order of magnitude and exceed the accuracy of reconstruction of multi-step algorithms used in DOT. (optical tomography)

  13. Quantitative analysis of the Stratus optical coherence tomography fast macular thickness map reports

    Directory of Open Access Journals (Sweden)

    Domalpally Amitha

    2010-01-01

    Full Text Available The cross sectional optical coherence tomography images have an important role in evaluating retinal diseases. The reports generated by the Stratus fast macular thickness scan protocol are useful for both clinical and research purposes. The centerpoint thickness is an important outcome measure for many therapeutic trials related to macular disease. The data is susceptible to artifacts such as decentration and boundary line errors and could be potentially erroneous. An understanding of how the data is generated is essential before utilizing the data. This article describes the interpretation of the fast macular thickness map report, assessment of the quality of an optical coherence tomography image and identification of the artifacts that could influence the numeric data.

  14. Early detection of tooth wear by en-face optical coherence tomography

    Science.gov (United States)

    Mărcăuteanu, Corina; Negrutiu, Meda; Sinescu, Cosmin; Demjan, Eniko; Hughes, Mike; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

    2009-02-01

    Excessive dental wear (pathological attrition and/or abfractions) is a frequent complication in bruxing patients. The parafunction causes heavy occlusal loads. The aim of this study is the early detection and monitoring of occlusal overload in bruxing patients. En-face optical coherence tomography was used for investigating and imaging of several extracted tooth, with a normal morphology, derived from patients with active bruxism and from subjects without parafunction. We found a characteristic pattern of enamel cracks in patients with first degree bruxism and with a normal tooth morphology. We conclude that the en-face optical coherence tomography is a promising non-invasive alternative technique for the early detection of occlusal overload, before it becomes clinically evident as tooth wear.

  15. Flow rate estimation by optical coherence tomography using contrast dilution approach

    Science.gov (United States)

    Štohanzlová, Petra; Kolář, Radim

    2015-07-01

    This paper describes experiments and methodology for flow rate estimation using optical coherence tomography and dilution method in single fiber setup. The single fiber is created from custom made glass capillary and polypropylene hollow fiber. As a data source, measurements on single fiber phantom with continuous flow of carrier medium and bolus of Intralipid solution as a contrast agent were used using Thorlabs OCT OCS1300SS. The measured data were processed by methods of image processing, in order to precisely align the individual images in the sequence and extract dilution curves from the area inside the fiber. An experiment proved that optical coherence tomography can be used for flow rate estimation by the dilution method with precision around 7%.

  16. Swept source optical coherence tomography based on non-uniform discrete fourier transform

    Institute of Scientific and Technical Information of China (English)

    Tong Wu; Zhihua Ding; Kai Wang; Chuan Wang

    2009-01-01

    A high-speed high-sensitivity swept source optical coherence tomography (SSOCT) system using a high speed swept laser source is developed.Non-uniform discrete fourier transform (NDFT) method is introduced in the SSOCT system for data processing.Frequency calibration method based on a Mach-Zender interferometer (MZI) and conventional data interpolation method is also adopted in the system for comparison.Optical coherence tomography (OCT) images from SSOCT based on the NDFT method,the MZI method,and the interpolation method are illustrated.The axial resolution of the SSOCT based on the NDFT method is comparable to that of the SSOCT system using MZI calibration method and conventional data interpolation method.The SSOCT system based on the NDFT method can achieve higher signal intensity than that of the system based on the MZI calibration method and conventional data interpolation method because of the better utilization of the power of source.

  17. High-resolution second-harmonic optical coherence tomography of collagen in rat-tail tendon

    Science.gov (United States)

    Jiang, Yi; Tomov, Ivan V.; Wang, Yimin; Chen, Zhongping

    2005-03-01

    A high-resolution second-harmonic optical coherence tomography (SH-OCT) system is demonstrated using a spectrum broadened femtosecond Ti :sapphire laser. An axial resolution of 4.2μm at the second-harmonic wave center wavelength of 400 nm has been achieved. Because the SH-OCT system uses the second-harmonic generation signals that strongly depend on the orientation, polarization, and local symmetry properties of chiral molecules, this technique provides unique contrast enhancement to conventional optical coherence tomography. The system is applied to image biological tissues of the rat-tail tendon. Highly organized collagen fibrils in the rat-tail tendon can be visualized in recorded images.

  18. Phase-sensitive multiple reference optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Dsouza, Roshan I.; Subhash, Hrebesh; Neuhaus, Kai; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2016-03-01

    Multiple reference OCT (MR-OCT) is a recently developed novel time-domain OCT platform based on a miniature reference arm optical delay, which utilizes a single miniature actuator and a partial mirror to generate recirculating optical delay for extended axial-scan range. MR-OCT technology promises to fit into a robust and cost-effective design, compatible with integration into consumer-level devices for addressing wide applications in mobile healthcare and biometry applications. Using conventional intensity based OCT processing techniques, the high-resolution structural imaging capability of MR-OCT has been recently demonstrated for various applications including in vivo human samples. In this study, we demonstrate the feasibility of implementing phase based processing with MR-OCT for various functional applications such as Doppler imaging and sensing of blood vessels, and for tissue vibrography applications. The MR-OCT system operates at 1310nm with a spatial resolution of ~26 µm and an axial scan rate of 600Hz. Initial studies show a displacement-sensitivity of ~20 nm to ~120 nm for the first 1 to 9 orders of reflections, respectively with a mirror as test-sample. The corresponding minimum resolvable velocity for these orders are ~2.3 µm/sec and ~15 µm/sec respectively. Data from a chick chorioallantoic membrane (CAM) model will be shown to demonstrate the feasibility of MR-OCT for imaging in-vivo blood flow.

  19. Optical coherence tomography based microangiography: A tool good for dermatology applications (Conference Presentation)

    Science.gov (United States)

    Wang, Ruikang K.; Baran, Utku; Choi, Woo J.

    2016-02-01

    Optical coherence tomography (OCT) based microangiography (OMAG) is a new imaging technique enabling the visualization of blood flow within microcirculatory tissue beds in vivo with high resolution. In this talk, the concept and advantages of OMAG will be discussed and its potential clinical applications in the dermatology will be shown, demonstrating its usefulness in the clinical monitoring and therapeutic treatment of various skin pathologies, e.g. acne, port wine stain and wound healing.

  20. Optical coherence tomography-current technology and applications in clinical and biomedical research

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Sander, Birgit; Mogensen, Mette

    2011-01-01

    Optical coherence tomography (OCT) is a noninvasive imaging technique that provides real-time two- and three-dimensional images of scattering samples with micrometer resolution. By mapping the local reflectivity, OCT visualizes the morphology of the sample. In addition, functional properties such...... biology. The number of companies involved in manufacturing OCT systems has increased substantially during the last few years (especially due to its success in opthalmology), and this technology can be expected to continue to spread into various fields of application....

  1. Automatic airway wall segmentation and thickness measurement for long-range optical coherence tomography images.

    Science.gov (United States)

    Qi, Li; Huang, Shenghai; Heidari, Andrew E; Dai, Cuixia; Zhu, Jiang; Zhang, Xuping; Chen, Zhongping

    2015-12-28

    We present an automatic segmentation method for the delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers are accurately extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with sheep airway OCT images. Quantitative thicknesses of the mucosal layers are obtained automatically for smoke inhalation injury experiments.

  2. Probing biological nanotopology via diffusion of weakly constrained plasmonic nanorods with optical coherence tomography

    OpenAIRE

    Chhetri, Raghav K.; Blackmon, Richard L.; Wu, Wei-Chen; Hill, David B.; Button, Brian; Casbas-Hernandez, Patricia; Troester, Melissa A; Tracy, Joseph B.; Oldenburg, Amy L.

    2014-01-01

    Many diseases are characterized by nanostructural changes in connective fibers and soluble proteins, which can indicate or drive disease progression. Noninvasive methods sensitive to nanotopological changes in 3D tissue models can elucidate biophysical changes associated with disease progression. Nanoparticles probe their environment via their diffusion, which is impacted by the size and connectivity of pores into which they freely diffuse. Here, we show that optical coherence tomography prov...

  3. Repeatability of Perimacular Ganglion Cell Complex Analysis with Spectral-Domain Optical Coherence Tomography

    OpenAIRE

    Ng, Dorothy S. K.; Preeti Gupta; Yih Chung Tham; Chye Fong Peck; Tien Yin Wong; Mohammad Kamran Ikram; Cheung, Carol Y.

    2015-01-01

    Purpose. To assess the repeatability of spectral-domain optical coherence tomography to measure macular and perimacular ganglion cell complex thicknesses and compare retinal ganglion cell parameters between algorithms. Methods. Ninety-two nonglaucomatous eyes from 92 participants underwent macular and perimacular ganglion cell complex thickness measurement using OCT-HS100 Glaucoma 3D algorithm and these measurements were repeated for 34 subjects. All subjects also had macular ganglion cell-in...

  4. Visualization of peripheral pulmonary artery red thrombi utilizing optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Cheng; Wang, Wei; Zhong, Nan Shan; Zeng, Guang Qiao; Zhang, Nuo Fu [The First Affiliated Hospital of Guangzhou Medical College, Guangzhou (China)

    2013-10-15

    Optical coherence tomography (OCT) is a new imaging technique capable of obtaining high-resolution intravascular images and has been used in interventional cardiology. However, an application of OCT in pulmonary arteries had seldom been documented. In this case, OCT imaging is performed in peripheral pulmonary arteries and shows mural red thrombi. Subsequently, the red thrombi are aspirated and confirmed by a histological examination. These findings suggest that OCT may be a useful tool to depict peripheral pulmonary artery thrombi.

  5. Analog CMOS circuit design and characterization for optical coherence tomography signal processing.

    Science.gov (United States)

    Kariya, Rajesh; Mathine, David L; Barton, Jennifer K

    2004-12-01

    We have developed a custom analog CMOS circuit to perform the signal processing for an optical coherence tomography imaging system. The circuit is realized in a 1.5 microm low-noise analog CMOS technology. The circuitry extracts the Doppler frequency from the signal and electrically mixes this with the original signal to provide a filtered A-scan. The circuitry was used to produce a two-dimensional image of an onion.

  6. Decreased light attenuation in cerebral cortex during cerebral edema detected using optical coherence tomography

    OpenAIRE

    Rodriguez, Carissa L. R.; Szu, Jenny I.; Eberle, Melissa M.; Wang, Yan; Hsu, Mike S.; Binder, Devin K.; Park, B. Hyle

    2014-01-01

    Abstract. Cerebral edema develops in response to a variety of conditions, including traumatic brain injury and stroke, and contributes to the poor prognosis associated with these injuries. This study examines the use of optical coherence tomography (OCT) for detecting cerebral edema in vivo. Three-dimensional imaging of an in vivo water intoxication model in mice was performed using a spectral-domain OCT system centered at 1300 nm. The change in attenuation coefficient was calculated and cere...

  7. Flow patterns on spectral-domain optical coherence tomography reveal flow directions at retinal vessel bifurcations

    DEFF Research Database (Denmark)

    Willerslev, Anne; Li, Xiao Q; Munch, Inger C

    2014-01-01

    PURPOSE: To study intravascular characteristics of flowing blood in retinal vessels using spectral-domain optical coherence tomography (SD-OCT). METHODS: Examination of selected arterial bifurcations and venous sites of confluence in 25 healthy 11-year-old children recruited as an ad hoc subsample...... be determined using SD-OCT. This feature may assist the identification of flow reversal near sites of vascular occlusion, the analysis of blood flow near vascular malformations and the segmentation of retinal SD-OCT images....

  8. Towards using spectral domain optical coherence tomography for dental wear monitoring

    Science.gov (United States)

    Mǎrcǎuteanu, Corina; Bradu, Adrian; Sinescu, Cosmin; Topalǎ, Florin I.; Negrutiu, Meda Lavinia; Podoleanu, Adrian G.

    2014-03-01

    In this paper we demonstrate that fast spectral domain optical coherence tomography imaging systems have the potential to monitor the evolution of pathological dental wear. On 10 caries free teeth, four levels of artificially defects similar to those observed in the clinic were created. After every level of induced defect, OCT scanning was performed. B-scans were acquired and 3D reconstructions were generated.

  9. Feasibility and methodology of optical coherence tomography imaging of human intracranial aneurysms: ex vivo pilot study

    Science.gov (United States)

    Vuong, Barry; Sun, Cuiru; Khiel, Tim-Rasmus; Gardecki, Joseph A.; Standish, Beau A.; da Costa, Leodante; de Morais, Josaphat; Tearney, Guillermo J.; Yang, Victor X. D.

    2012-02-01

    Rupture of intracranial aneurysm is a common cause of subarachnoid hemorrhage. An aneurysm may undergo microscopic morphological changes or remodeling of the vessel wall prior to rupture, which could potentially be imaged. In this study we present methods of tissue sample preparation of intracranial aneurysms and correlation between optical coherence tomography imaging and routine histology. OCT has a potential future in the assessment of microscopic features of aneurysms, which may correlate to the risk of rupture.

  10. High-resolution spectral domain anterior segment optical coherence tomography in type 1 boston keratoprosthesis

    OpenAIRE

    2013-01-01

    Purpose: To report the results of imaging using high-resolution, Fourier domain anterior segment optical coherence tomography (AS-OCT) to evaluate patients with a type 1 Boston Keratoprosthesis (KPro). Methods: We performed a retrospective comparative study of patients in whom we implanted the Boston KPro. A total of 26 eyes of 23 patients from the Cornea Service at the University of California Davis Eye Center were included. Subjects were evaluated with the Spectralis AS-OCT (Heidelberg Engi...

  11. Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography.

    Science.gov (United States)

    Lee, Jonghwan; Wu, Weicheng; Lesage, Frederic; Boas, David A

    2013-11-01

    As capillaries exhibit heterogeneous and fluctuating dynamics even during baseline, a technique measuring red blood cell (RBC) speed and flux over many capillaries at the same time is needed. Here, we report that optical coherence tomography can capture individual RBC passage simultaneously over many capillaries located at different depths. Further, we demonstrate the ability to quantify RBC speed, flux, and linear density. This technique will provide a means to monitor microvascular flow dynamics over many capillaries at different depths at the same time.

  12. Application of optical coherence tomography enhances reproducibility of arthroscopic evaluation of equine joints

    OpenAIRE

    Niemelä, Tytti; Virén, Tuomas; Liukkonen, Jukka; te Moller, Nikae; Puhakka, Pia H.; Jurvelin, Jukka S.; Tulamo, R.M.; Töyräs, Juha

    2014-01-01

    Background: Arthroscopy is widely used in various equine joints for diagnostic and surgical purposes. However, accuracy of defining the extent of cartilage lesions and reproducibility in grading of lesions are not optimal. Therefore, there is a need for new, more quantitative arthroscopic methods. Arthroscopic optical coherence tomography (OCT) imaging is a promising tool introduced for quantitative detection of cartilage degeneration and scoring of the severity of chondral lesions. The aim o...

  13. Application of optical coherence tomography enhances reproducibility of arthroscopic evaluation of equine joints

    OpenAIRE

    Niemelä, Tytti; Virén, Tuomas; Liukkonen, Jukka; Argüelles, David; te Moller, Nikae C R; Puhakka, Pia H.; Jurvelin, Jukka S.; Tulamo, Riitta-Mari; Töyräs, Juha

    2014-01-01

    Background Arthroscopy is widely used in various equine joints for diagnostic and surgical purposes. However, accuracy of defining the extent of cartilage lesions and reproducibility in grading of lesions are not optimal. Therefore, there is a need for new, more quantitative arthroscopic methods. Arthroscopic optical coherence tomography (OCT) imaging is a promising tool introduced for quantitative detection of cartilage degeneration and scoring of the severity of chondral lesions. The aim of...

  14. X-ray tomography for structural analysis of microstructured and multimaterial optical fibers and preforms.

    Science.gov (United States)

    Sandoghchi, S R; Jasion, G T; Wheeler, N V; Jain, S; Lian, Z; Wooler, J P; Boardman, R P; Baddela, N; Chen, Y; Hayes, J; Fokoua, E Numkam; Bradley, T; Gray, D R; Mousavi, S M; Petrovich, M; Poletti, F; Richardson, D J

    2014-10-20

    Specialty optical fibers, in particular microstructured and multi-material optical fibers, have complex geometry in terms of structure and/or material composition. Their fabrication, although rapidly developing, is still at a very early stage of development compared with conventional optical fibers. Structural characterization of these fibers during every step of their multi-stage fabrication process is paramount to optimize the fiber-drawing process. The complexity of these fibers restricts the use of conventional refractometry and microscopy techniques to determine their structural and material composition. Here we present, to the best of our knowledge, the first nondestructive structural and material investigation of specialty optical fibers using X-ray computed tomography (CT) methods, not achievable using other techniques. Recent advances in X-ray CT techniques allow the examination of optical fibers and their preforms with sub-micron resolution while preserving the specimen for onward processing and use. In this work, we study some of the most challenging specialty optical fibers and their preforms. We analyze a hollow core photonic band gap fiber and its preforms, and bond quality at the joint between two fusion-spliced hollow core fibers. Additionally, we studied a multi-element optical fiber and a metal incorporated dual suspended-core optical fiber. The application of X-ray CT can be extended to almost all optical fiber types, preforms and devices.

  15. Optical coherence tomography of the preterm eye: from retinopathy of prematurity to brain development

    Directory of Open Access Journals (Sweden)

    Rothman AL

    2016-05-01

    Full Text Available Adam L Rothman,1,2 Shwetha Mangalesh,1 Xi Chen,1 Cynthia A Toth1,3 1Department of Ophthalmology, Duke University School of Medicine, Durham, 2Department of Internal Medicine, Cone Health, Greensboro, 3Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA Abstract: Preterm infants with retinopathy of prematurity are at increased risk of poor neurodevelopmental outcomes. Because the neurosensory retina is an extension of the central nervous system, anatomic abnormalities in the anterior visual pathway often relate to system and central nervous system health. We describe optical coherence tomography as a powerful imaging modality that has recently been adapted to the infant population and provides noninvasive, high-resolution, cross-sectional imaging of the infant eye at the bedside. Optical coherence tomography has increased understanding of normal eye development and has identified several potential biomarkers of brain abnormalities and poorer neurodevelopment. Keywords: preterm infant, optical coherence tomography, neurosensory retina, biomarkers, retinopathy, brain development

  16. The complementary benefit of anterior segment optical coherence tomography in penetrating keratoplasty

    Directory of Open Access Journals (Sweden)

    Yenerel NM

    2013-07-01

    Full Text Available Nursal Melda Yenerel,1 Raciha Beril Kucumen,2 Ebru Gorgun3 1Haydarpasa Numune Research and Training Hospital, Istanbul, Turkey; 2Yeditepe University Medical Faculty, Department of Ophthalmology, Istanbul, Turkey; 3Dunya Goz Eye Hospital, Istanbul, Turkey Purpose: To evaluate the utility of anterior segment optical coherence tomography (AS-OCT assessment in the pre- and postsurgical management of full-thickness corneal grafts. Methods: Seventy eyes of 58 patients who had penetrating keratoplasty were included in the study. High resolution AS-OCT scans of the cornea and the anterior segment were performed before and after transplantation in 17 eyes with the VisanteTM optical coherence tomography. Fifty-three eyes were examined in the late postoperative period. Results: The mean follow-up was 4.3 years (range, 1–15 years. Six different graft–host junctions were identified. Three patients with graft rejection, four patients with anterior synechia, and three patients with corneal ulcer were evaluated. Preoperative evaluation of eyes with semiopaque and totally opaque corneas revealed important information about anterior segment structures additional to slit-lamp findings. Conclusion: AS-OCT is a useful complementary tool for the evaluation of penetrating corneal transplantation surgery and in the management of its postoperative complications. Keywords: anterior segment optical coherence tomography, imaging techniques, penetrating keratoplasty

  17. Optical Doppler tomography and spectral Doppler imaging of localized ischemic stroke in a mouse model

    Science.gov (United States)

    Yu, Lingfeng; Nguyen, Elaine; Liu, Gangjun; Rao, Bin; Choi, Bernard; Chen, Zhongping

    2010-02-01

    We present a combined optical Doppler tomography/spectral Doppler imaging modality to quantitatively evaluate the dynamic blood circulation and the artery blockage before and after a localized ischemic stroke in a mouse model. Optical Doppler Tomography (ODT) combines the Doppler principle with optical coherence tomography for noninvasive localization and measurement of particle flow velocity in highly scattering media with micrometer scale spatial resolution. Spectral Doppler imaging (SDI) provides complementary temporal flow information to the spatially distributed flow information of Doppler imaging. Fast, repeated, ODT scans across an entire vessel were performed to record flow dynamic information with high temporal resolution of cardiac cycles. Spectral Doppler analysis of continuous Doppler images demonstrates how the velocity components and longitudinally projected flow-volume-rate change over time for scatters within the imaging volume using spectral Doppler waveforms. Furthermore, vascular conditions can be quantified with various Doppler-angle-independent flow indices. Non-invasive in-vivo mice experiments were performed to evaluate microvascular blood circulation of a localized ischemic stroke mouse model.

  18. Characteristics of polyacrylamide gel with THPC and Turnbull Blue gel dosimeters evaluated using optical tomography

    Science.gov (United States)

    Pilařová (Vávrů), Kateřina; Kozubíková, Petra; Šolc, Jaroslav; Spěváček, Václav

    2014-11-01

    The purpose of this study was to compare characteristics of radiochromic gel - Turnbull Blue gel (TB gel) with polymer gel - polyacrylamide gel and tetrakis hydroxymethyl phosphonium chloride (PAGAT) using optical tomography. Both types of gels were examined in terms of dose sensitivity, dose response linearity and background value of spectrophotometric absorbance. The calibration curve was obtained for 60Co irradiation performed on Gammacell 220 at predefined gamma dose levels between 0 and 140 Gy for TBG and 0-15 Gy for PAGAT. To measure relative dose distributions from stereotactic irradiation, dosimeters were irradiated on Leksell Gamma Knife Perfexion. The cylindrical glass housings filled with gel were attached to the stereotactic frame. They were exposed with single shot and 16 mm collimator by 65 Gy to a 50% prescription isodose for TB gel and 4 Gy to a 50% prescription isodose for PAGAT. Evaluations of dosimeters were performed on an UV-vis Spectrophotometer Helios β and an optical cone beam homemade tomography scanner with a 16-bit astronomy CCD camera with a set of color filters. The advantages and potential disadvantages for both types of gel dosimeters were summarized. Dose distribution in central slice and measured profiles of 16 mm shot shows excellent correspondence with treatment planning system Leksell GammaPlan® for both PAGAT and Turnbull Blue gels. Gel dosimeters are suitable for steep dose gradient verification. An optical tomography evaluation method is successful. Dose response characteristics of TB gel and PAGAT gel are presented.

  19. Correlation of optic neuritis and retinal nerve fibre thickness using optical coherence tomography in a cohort of multiple sclerosis patients

    Directory of Open Access Journals (Sweden)

    Izanne Roos

    2016-03-01

    Full Text Available Background: Optical coherence tomography (OCT is a fast, non-invasive imaging technology that produces 3D, high-resolution images of the retina. Direct visualisation of the retina allows a unique opportunity to study the effects of multiple sclerosis (MS-associated neurodegeneration on retinal ganglion cells as well as effects of retrobulbar demyelination on axonal and retinal architecture through measurement of retinal nerve fibre layer (RNFL thickness and total macular volume (TMV. These findings are clinically important as axonal loss is irreversible and correlates with disability.Aim: To determine the role and usefulness of OCT in a local cohort of MS patients.Setting: Neurology Clinic, Inkosi Albert Luthuli Central Hospital, KwaZulu-Natal, South Africa.Methods: Nineteen patients with MS currently being treated with interferon β-1b underwent OCT examination of both eyes. RNFL thickness and macular volume were measured and correlated with clinical disease characteristics, history of optic neuritis and level of disability.Results: Mean RNFL thickness was 77.3 μm with no significant difference in mean RNFL in eyes with a history of optic neuritis (ON and those without (p = 0.4. Eyes with a history of ON did, however, have significantly thinner RNFL compared with the contralateral eye (p = 0.04. Despite a strong correlation between TMV and RNFL (p = 0.001, a subset of patients with normal RNFL had TMV that was less than 1% of what was expected. There was no correlation between RNFL and disability scores.Conclusion: OCT enables a direct axonal ‘optical biopsy’, for monitoring disease progression and treatment response in MS. RNFL thinning occurs independently of a history of optic neuritis and may represent a chronic optic neuropathy in patients with MS.Keywords: Multiple sclerosis; optical coherence tomography

  20. Polarization-sensitive swept-source optical coherence tomography with continuous source polarization modulation

    OpenAIRE

    Yamanari, Masahiro; Makita, Shuichi; Yasuno, Yoshiaki

    2008-01-01

    We present fiber-based polarization-sensitive swept-source optical coherence tomography (SS-OCT) based on continuous source polarization modulation. The light source is a frequency swept laser centered at 1.31 μm with a scanning rate of 20 kHz. The incident polarization is modulated by a resonant electro-optic modulator at 33.3 MHz, which is one-third of the data acquisition frequency. The zeroth- and first-order harmonic components of the OCT signals with respect to the polarization modulati...

  1. Dual-path handheld system for cornea and retina imaging using optical coherence tomography

    Science.gov (United States)

    Shirazi, Muhammad Faizan; Wijesinghe, Ruchire Eranga; Ravichandran, Naresh Kumar; Kim, Pilun; Jeon, Mansik; Kim, Jeehyun

    2016-11-01

    A dual-path handheld system is proposed for cornea and retina imaging using spectral domain optical coherence tomography. The handheld sample arm is designed to acquire two images simultaneously. Both eyes of a person can be imaged at the same time to obtain the images of the cornea of one eye and the retina of the other eye. Cornea, retina, and optic disc images are acquired with the proposed sample arm. Experimental results demonstrate the usefulness of this system for imaging of different eye segments. This system reduces the time required for imaging of the two eyes and is cost effective.

  2. Calibration-free B-scan images produced by master/slave optical coherence tomography

    OpenAIRE

    Bradu, Adrian; Podoleanu, Adrian G.H.

    2014-01-01

    We report on a novel method to produce B-scan images in spectral domain optical coherence tomography (SD-OCT). The method proceeds in two steps. In the first step, using a mirror in the sample arm of the interferometer, channeled spectra are acquired for different values of the optical path difference (OPD) and stored as masks. In the second step, the mirror is replaced with an object and the captured channelled spectrum is correlated with each mask, providing the interference strength from t...

  3. Towards multimodal detection of melanoma thickness based on optical coherence tomography and optoacoustics

    Science.gov (United States)

    Rahlves, M.; Varkentin, A.; Stritzel, J.; Blumenröther, E.; Mazurenka, M.; Wollweber, M.; Roth, B.

    2016-03-01

    Melanoma skin cancer has one of the highest mortality rates of all types of cancer if not detected at an early stage. The survival rate is highly dependent on its penetration depth, which is commonly determined by histopathology. In this work, we aim at combining optical coherence tomography and optoacoustic as a non-invasive all-optical method to measure the penetration depth of melanoma. We present our recent achievements to setup a handheld multimodal device and also results from first in vivo measurements on healthy and cancerous skin tissue, which are compared to measurements obtained by ultrasound and histopathology.

  4. Speckle decorrelation in Ultrasound-modulated optical tomography made by heterodyne holography

    CERN Document Server

    Gross, M

    2016-01-01

    Ultrasound-modulated optical tomography (UOT) is a technique that images optical contrast deep inside scattering media. Heterodyne holography is a promising tool able to detect the UOT tagged photons with high efficiency. In this work, we describe theoretically the detection of the tagged photon in heterodyne holography based UOT, show how to filter the untagged photon discuss, and discuss the effect of speckle decorrelation. We show that optimal detection sensitivity can obtain, if the frame exposure time is of the order of the decorrelation time.

  5. In-vivo retinal imaging by optical coherence tomography using an RSOD-based phase modulator

    Institute of Scientific and Technical Information of China (English)

    Ling WANG; Zhi-hua DING; Guo-hua SHI; Yu-dong ZHANG

    2009-01-01

    Fourier-domain rapid scanning optical delay line (RSOD) was introduced for phase modulation and depth scanning in a time-domain optical coherence tomography (TD-OCT) system. Investigation of parameter optimization of RSOD was conducted.Experiments for RSOD characterization at different parameters of the groove pitch, focal length, galvomirror size, etc. were performed. By implementing the optimized RSOD in our established TD-OCT system with a broadband light source centered at 840 nm with 50 nm bandwidth, in vivo retina imaging of a rabbit was presented, demonstrating the feasibility of high-quality TD-OCT imaging using an RSOD-based phase modulator.

  6. Real time mass flow rate measurement using multiple fan beam optical tomography.

    Science.gov (United States)

    Abdul Rahim, R; Leong, L C; Chan, K S; Rahiman, M H; Pang, J F

    2008-01-01

    This paper presents the implementing multiple fan beam projection technique using optical fibre sensors for a tomography system. From the dynamic experiment of solid/gas flow using plastic beads in a gravity flow rig, the designed optical fibre sensors are reliable in measuring the mass flow rate below 40% of flow. Another important matter that has been discussed is the image processing rate or IPR. Generally, the applied image reconstruction algorithms, the construction of the sensor and also the designed software are considered to be reliable and suitable to perform real-time image reconstruction and mass flow rate measurements.

  7. Imaging hemodynamic changes in preterm infant brains with two-dimensional diffuse optical tomography

    Science.gov (United States)

    Gao, Feng; Ma, Yiwen; Yang, Fang; Zhao, Huijuan; Jiang, Jingying; Kusaka, Takashi; Ueno, Masanori; Yamada, Yukio

    2008-02-01

    We present our preliminary results on two-dimensional (2-D) optical tomographic imaging of hemodynamic changes of two preterm infant brains in different ventilation settings conditions. The investigations use the established two-wavelength, 16-channel time-correlated single photon counting system for the detection, and the generalized pulse spectrum technique based algorithm for the image reconstruction. The experiments demonstrate that two-dimensional diffuse optical tomography may be a potent and relatively simple way of investigating the functions and neural development of infant brains in the perinatal period.

  8. A signal separation technique for sub-cellular imaging using dynamic optical coherence tomography

    CERN Document Server

    Ammari, Habib; Shi, Cong

    2016-01-01

    This paper aims at imaging the dynamics of metabolic activity of cells. Using dynamic optical coherence tomography, we introduce a new multi-particle dynamical model to simulate the movements of the collagen and the cell metabolic activity and develop an efficient signal separation technique for sub-cellular imaging. We perform a singular-value decomposition of the dynamic optical images to isolate the intensity of the metabolic activity. We prove that the largest eigenvalue of the associated Casorati matrix corresponds to the collagen. We present several numerical simulations to illustrate and validate our approach.

  9. Versatile Wideband Balanced Detector for Quantum Optical Homodyne Tomography

    CERN Document Server

    Kumar, Ranjeet; MacRae, Andrew; Cairns, E; Huntington, E H; Lvovsky, A I

    2011-01-01

    We present a comprehensive theory and an easy to follow method for the design and construction of a wideband homodyne detector for time-domain quantum measurements. We show how one can evaluate the performance of a detector in a specific time-domain experiment based on electronic spectral characteristic of that detector. We then present and characterize a high-performance detector constructed using inexpensive, commercially available components such as low-noise high-speed operational amplifiers and high-bandwidth photodiodes. Our detector shows linear behavior up to a level of over 13 dB clearance between shot noise and electronic noise, in the range from DC to 100 MHz. The detector can be used for measuring quantum optical field quadratures both in the continuous-wave and pulsed regimes with pulse repetition rates up to about 250 MHz.

  10. Diagnostic ability of barrett's index to detect dysthyroid optic neuropathy using multidetector computed tomography

    Directory of Open Access Journals (Sweden)

    Mário L. R. Monteiro

    2008-01-01

    Full Text Available OBJECTIVES: The objective of this study was to evaluate the ability of a muscular index (Barrett's Index, calculated with multidetector computed tomography, to detect dysthyroid optic neuropathy in patients with Graves' orbitopathy. METHODS: Thirty-six patients with Graves' orbitopathy were prospectively studied and submitted to neuro-ophthalmic evaluation and multidetector computed tomography scans of the orbits. Orbits were divided into two groups: those with and without dysthyroid optic neuropathy. Barrett's index was calculated as the percentage of the orbit occupied by muscles. Sensitivity and specificity were determined for several index values. RESULTS: Sixty-four orbits (19 with and 45 without dysthyroid optic neuropathy met the inclusion criteria for the study. The mean Barrett's index values (± SD were 64.47% ± 6.06% and 49.44% ± 10.94%in the groups with and without dysthyroid optic neuropathy, respectively (p60% should be carefully examined and followed for the development of dysthyroid optic neuropathy.

  11. Improvement of tissue analysis and classification using optical coherence tomography combined with Raman spectroscopy

    Science.gov (United States)

    Liu, Chih-Hao; Qi, Ji; Lu, Jing; Wang, Shang; Wu, Chen; Shih, Wei-Chuan; Larin, Kirill V.

    2014-02-01

    Optical coherence tomography (OCT) is an optical imaging technique that is capable of performing high-resolution (approaching the histopathology level) and real-time imaging of tissues without use of contrast agents. Based on these advantages, the pathological features of tumors (in micro scale) can be identified during resection surgery. However, the accuracy of tumor margin prediction still needs to be enhanced for assisting the judgment of surgeons. In this regard, we present a two-dimensional computational method for advanced tissue analysis and characterization based on optical coherence tomography (OCT) and Raman spectroscopy (RS). The method combines the slope of OCT intensity signal and the Principal component (PC) of RS, and relies on the tissue optical attenuation and chemical ingredients for the classification of tissue types. Our pilot experiments were performed on mouse kidney, liver and small intestine. Results demonstrate the improvement of the tissue differentiation compared with the analysis only based on the OCT detection. This combined OCT/RS method is potentially useful as a novel optical biopsy technique for cancer detection.

  12. Spectral Domain Optical Coherence Tomography in Diffuse Unilateral Subacute Neuroretinitis

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre de A. Garcia Filho

    2011-01-01

    Full Text Available Purpose. To describe the SD-OCT findings in patients with diffuse unilateral subacute neuroretinitis (DUSN and evaluate CRT and RNFL thickness. Methods. Patients with clinical diagnosis of DUSN who were submitted to SD-OCT were included in the study. Complete ophthalmologic examination and SD-OCT were performed. Cirrus scan strategy protocols used were macular cube, optic nerve head cube, and HD-5 line raster. Results. Eight patients with DUSN were included. Mean RNFL thickness was 80.25 μm and 104.75 μm for affected and normal eyes, respectively. Late stage had mean RNFL thickness of 74.83 μm compared to 96.5 μm in early stage. Mean CMT was 205.5 μm for affected eyes and 255.13 μm for normal fellow eyes. Conclusion. RNFL and CMT were thinner in DUSN eyes compared to normal eyes. Late-stage disease had more pronounced thinning compared to early-stage patients. This thinning in RNFL and CMT may reflect the low visual acuity in patients with DUSN.

  13. Optical tomography reconstruction algorithm with the finite element method: An optimal approach with regularization tools

    Energy Technology Data Exchange (ETDEWEB)

    Balima, O., E-mail: ofbalima@gmail.com [Département des Sciences Appliquées, Université du Québec à Chicoutimi, 555 bd de l’Université, Chicoutimi, QC, Canada G7H 2B1 (Canada); Favennec, Y. [LTN UMR CNRS 6607 – Polytech’ Nantes – La Chantrerie, Rue Christian Pauc, BP 50609 44 306 Nantes Cedex 3 (France); Rousse, D. [Chaire de recherche industrielle en technologies de l’énergie et en efficacité énergétique (t3e), École de technologie supérieure, 201 Boul. Mgr, Bourget Lévis, QC, Canada G6V 6Z3 (Canada)

    2013-10-15

    Highlights: •New strategies to improve the accuracy of the reconstruction through mesh and finite element parameterization. •Use of gradient filtering through an alternative inner product within the adjoint method. •An integral form of the cost function is used to make the reconstruction compatible with all finite element formulations, continuous and discontinuous. •Gradient-based algorithm with the adjoint method is used for the reconstruction. -- Abstract: Optical tomography is mathematically treated as a non-linear inverse problem where the optical properties of the probed medium are recovered through the minimization of the errors between the experimental measurements and their predictions with a numerical model at the locations of the detectors. According to the ill-posed behavior of the inverse problem, some regularization tools must be performed and the Tikhonov penalization type is the most commonly used in optical tomography applications. This paper introduces an optimized approach for optical tomography reconstruction with the finite element method. An integral form of the cost function is used to take into account the surfaces of the detectors and make the reconstruction compatible with all finite element formulations, continuous and discontinuous. Through a gradient-based algorithm where the adjoint method is used to compute the gradient of the cost function, an alternative inner product is employed for preconditioning the reconstruction algorithm. Moreover, appropriate re-parameterization of the optical properties is performed. These regularization strategies are compared with the classical Tikhonov penalization one. It is shown that both the re-parameterization and the use of the Sobolev cost function gradient are efficient for solving such an ill-posed inverse problem.

  14. Using swept source optical coherence tomography to monitor wound healing in tissue engineered skin

    Science.gov (United States)

    Smith, L. E.; Lu, Z.; Bonesi, M.; Smallwood, R.; Matcher, S. J.; MacNeil, S.

    2010-02-01

    There is an increasing need for a robust simple to use non-invasive imaging technology for monitoring tissue engineered constructs as they develop. We have applied optical coherence tomography (OCT), a relatively new optical technique, to image tissue engineered constructs. Our aim was to evaluate the use of swept-source optical coherence tomography (SSOCT) to non-invasively image reconstructed skin as it developed over several weeks. The epidermis of the reconstructed skin was readily distinguished from the neodermis when examined with standard histology - a destructive imaging technique - of samples. The development of reconstructed skin based on deepithelialised acellular dermis (DED) was accurately monitored with SS-OCT over three weeks and confirmed with conventional histology. It was also possible to image changes in the epidermis due to the presence of melanoma and the healing of these 3D models after wounding with a scalpel, with or without the addition of a fibrin clot. SS-OCT is proving to be a valuable tool in tissue engineering, showing great promise for the non-invasive imaging of optically turbid tissue engineered constructs, including tissue engineered skin.

  15. Decreased retinal nerve fibre layer thickness detected by optical coherence tomography in patients with ethambutol‐induced optic neuropathy

    Science.gov (United States)

    Chai, Samantha J; Foroozan, Rod

    2007-01-01

    Background It is difficult to assess the degree of optic nerve damage in patients with ethambutol‐induced optic neuropathy, especially just after the onset of visual loss, when the optic disc typically looks normal. Aim To evaluate changes in retinal nerve fibre layer thickness (RNFLT) using optical coherence tomography (OCT) in patients with optic neuropathy within 3 months of cessation of ethambutol treatment. Design A retrospective observational case series from a single neuro‐ophthalmology practice. Methods 8 patients with a history of ethambutol‐induced optic neuropathy were examined within 3 months after stopping ethambutol treatment. All patients underwent a neuro‐ophthalmologic examination, including visual acuity, colour vision, visual fields and funduscopy. OCT was performed on both eyes of each patient using the retinal nerve fibre layer analysis protocol. Results The interval between cessation of ethambutol treatment and the initial visit ranged from 1 week to 3 months. All patients had visual deficits characteristic of ethambutol‐induced optic neuropathy at their initial visit, and the follow‐up examination was performed within 12 months. Compared with the initial RNFLT, there was a statistically significant decrease in the mean RNFLT of the temporal, superior and nasal quadrants (p = 0.009, 0.019 and 0.025, respectively), with the greatest decrease in the temporal quadrant (mean decrease 26.5 μm). Conclusions A decrease in RNFLT is observed in all quadrants in patients with ethambutol‐induced optic neuropathy who have recently discontinued the medication. This decrease is most pronounced in the temporal quadrant of the optic disc. PMID:17215265

  16. OPTICAL TOMOGRAPHY: Nanoparticles as contrast-enhancing agents in optical coherence tomography imaging of the structural components of skin: Quantitative evaluation

    Science.gov (United States)

    Kirillin, M. Yu; Agrba, P. D.; Sirotkina, M. A.; Shiryamova, M. V.; Zagainova, E. V.; Kamenskii, V. A.

    2010-08-01

    This work examines the effect of gold nanoshells and titania nanoparticles on the imaging contrast of structural components of skin in optical coherence tomography (OCT). Experimental data are compared to Monte Carlo (MC) simulation results. In experiments with pig skin in vivo, the epidermis — dermis contrast is improved from 0.78 ± 0.03 to 0.92 ± 0.04 by gold nanoshells applied to the skin surface and from 0.78 ± 0.03 to 0.86 ± 0.04 by titania nanoparticles. The contrast of glands is enhanced by titania from 0.68 ± 0.12 to 0.84 ± 0.07. The highest contrast is reached 120 — 150 min after applying gold nanoshells and 160 — 200 min after applying titania. According to the MC simulation results, the contrast of inclusions increases from zero to 0.85 and 0.65, respectively.

  17. Extraction of linear anisotropic parameters using optical coherence tomography and hybrid Mueller matrix formalism.

    Science.gov (United States)

    Liao, Chia-Chi; Lo, Yu-Lung

    2015-04-20

    A method is proposed for extracting the linear birefringence (LB) and linear dichroism (LD) properties of an anisotropic optical sample using reflection-mode optical coherence tomography (OCT) and a hybrid Mueller matrix formalism. To ensure the accuracy of the extracted parameter values, a method is proposed for calibrating and compensating the polarization distortion effect induced by the beam splitters in the OCT system using a composite quarter-waveplate / half-waveplate / quarter-waveplate structure. The validity of the proposed method is confirmed by extracting the LB and LD properties of a quarter-wave plate and a defective polarizer. To the best of the authors' knowledge, the method proposed in this study represents the first reported attempt to utilize an inverse Mueller matrix formalism and a reflection-mode OCT structure to extract the LB and LD parameters of optically anisotropic samples.

  18. AM ultrasound-modulated optical tomography with real-time FFT

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We report on a novel ultrasound-modulated optical tomographic technique applied in dense tissue-simulating turbid media. A 1 MHz ultrasound beam is focused into the media to modulate and tag the scattering laser light passing through the ultrasonic focused zone. A 10 kHz sinusoidal wave, as a detection wave, is carried by the ultrasound beam through amplitude-modulation (AM). The scattering photons that come from the focused zone carry the modulated information, received by detector and demodulated by real-time fast Fourier transform (FFT). The optical tomographic images of the tissue simulating media and buried object are reconstructed with AM spectral intensity. This method can be applied to imaging three-dimensional tissue structures with different optical parameters. For the first time, we obtained the tomography of buried objects in biological tissue phantoms with a detecting depth of 30 mm.

  19. Parameters measurement of rigid gas permeable contact lens based on optical coherence tomography

    Science.gov (United States)

    Zhu, Dexi; Shen, Meixiao; Li, Yiyu

    2012-10-01

    Spectral domain optical coherence tomography (OCT) was developed in order to measure the geometric parameters of rigid gas permeable (RGP) contact lens. With custom designed OCT system, an ultra-high axial resolution of 3.3 μm in lens was achieved. The OCT image was corrected to eliminate the optical distortion and actual surfaces of lens were shown in contour map. Central thickness, lens diameter, base curve and front surface curvature at optical zone were calculated from the contour map. The results match well with the real values measured by conventional instruments. Our research indicates that OCT can be used to test the RGP lens in a simple and exact way.

  20. Fiber-Based Polarization Diversity Detection for Polarization-Sensitive Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Hamid Pahlevaninezhad

    2014-09-01

    Full Text Available We present a new fiber-based polarization diversity detection (PDD scheme for polarization sensitive optical coherence tomography (PSOCT. This implementation uses a new custom miniaturized polarization-maintaining fiber coupler with single mode (SM fiber inputs and polarization maintaining (PM fiber outputs. The SM fiber inputs obviate matching the optical lengths of the two orthogonal OCT polarization channels prior to interference while the PM fiber outputs ensure defined orthogonal axes after interference. Advantages of this detection scheme over those with bulk optics PDD include lower cost, easier miniaturization, and more relaxed alignment and handling issues. We incorporate this PDD scheme into a galvanometer-scanned OCT system to demonstrate system calibration and PSOCT imaging of an achromatic quarter-wave plate, fingernail in vivo, and chicken breast, salmon, cow leg, and basa fish muscle samples ex vivo.

  1. Bilateral Vitreopapillary Traction Demonstrated by Optical Coherence Tomography Mistaken for Papilledema

    Directory of Open Access Journals (Sweden)

    Elizabeth Houle

    2012-01-01

    Full Text Available Purpose. The purpose of this study was to report a case of bilateral vitreopapillary traction, previously misdiagnosed as papilledema. Methods. A case report is presented of a 47-year-old woman with a prior diagnosis of papilledema, who is shown to have bilateral vitreopapillary traction rather than true optic disc swelling, confirmed by optical coherence tomography (OCT. Results. OCT showed vitreous traction surrounding the optic discs of both eyes. Fluorescein angiography demonstrated focal leakage of both discs. Conclusion. Bilateral disc elevation caused by vitreous traction can be confused with papilledema. In such cases, OCT can be used to arrive at the correct diagnosis. Although the phenomenon of vitreopapillary traction is well reported, this case indicates that not all ophthalmologists recognize the condition.

  2. Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography.

    Science.gov (United States)

    Maia, Ana Marly Araújo; de Freitas, Anderson Zanardi; de L Campello, Sergio; Gomes, Anderson Stevens Leônidas; Karlsson, Lena

    2016-06-01

    An in vitro study of morphological alterations between sound dental structure and artificially induced white spot lesions in human teeth, was performed through the loss of fluorescence by Quantitative Light-Induced Fluorescence (QLF) and the alterations of the light attenuation coefficient by Optical Coherence Tomography (OCT). To analyze the OCT images using a commercially available system, a special algorithm was applied, whereas the QLF images were analyzed using the software available in the commercial system employed. When analyzing the sound region against white spot lesions region by QLF, a reduction in the fluorescence intensity was observed, whilst an increase of light attenuation by the OCT system occurred. Comparison of the percentage of alteration between optical properties of sound and artificial enamel caries regions showed that OCT processed images through the attenuation of light enhanced the tooth optical alterations more than fluorescence detected by QLF System. QLF versus OCT imaging of enamel caries: a photonics assessment.

  3. Optical Coherence Tomography in Multiple Sclerosis and Neuromyelitis Optica: An Update

    Directory of Open Access Journals (Sweden)

    Susana Noval

    2011-01-01

    Full Text Available Optical coherence tomography (OCT uses light interference patterns to produce a cross-sectional image of the retina. It is capable of measuring the unmyelinated axons of the retinal ganglionar cells as they converge on the optic disc. In a disease like multiple sclerosis (MS, in which axonal loss has been identified as an important cause of sustained disability, it may prove an invaluable tool. OCT has demonstrated that axonal loss occurs after each episode of optic neuritis and that the degree of axonal loss is correlated to visual outcomes. Furthermore, axonal loss occurs in MS even in the absence of inflammatory episodes, and the degree of this loss is correlated with the duration of the disease process, with more thinning as the disease advances and in progressive forms. Thus, OCT retinal nerve fiber layer measurements may represent an objective outcome measure with which to evaluate the effect of treatment.

  4. Identification of prefrontal cortex (BA10) activation while performing Stroop test using diffuse optical tomography

    Science.gov (United States)

    Khadka, Sabin; Chityala, Srujan R.; Tian, Fenghua; Liu, Hanli

    2011-03-01

    Stroop test is commonly used as a behavior-testing tool for psychological examinations that are related to attention and cognitive control of the human brain. Studies have shown activations in Broadmann area 10 (BA10) of prefrontal cortex (PFC) during attention and cognitive process. The use of diffuse optical tomography (DOT) for human brain mapping is becoming more prevalent. In this study we expect to find neural correlates between the performed cognitive tasks and hemodynamic signals detected by a DOT system. Our initial observation showed activation of oxy-hemoglobin concentration in BA 10, which is consistent with some results seen by positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). Our study demonstrates the possibility of combining DOT with Stroop test to quantitatively investigate cognitive functions of the human brain at the prefrontal cortex.

  5. Impact of non-stationary optical illumination on image reconstruction in optoacoustic tomography

    CERN Document Server

    Lou, Yang; Oraevsky, Alexander A; Anastasio, Mark A

    2016-01-01

    Optoacoustic tomography (OAT), also known as photoacoustic tomography, is a rapidly emerging hybrid imaging technique that possesses great potential for a wide range of biomedical imaging applications. In OAT, a laser is employed to illuminate the tissue of interest and acoustic signals are produced via the photoacoustic effect. From these data, an estimate of the distribution of the absorbed optical energy density within the tissue is reconstructed, referred to as the object function. This quantity is defined, in part, by the distribution of light fluence within the tissue that is established by the laser source. When performing three-dimensional imaging of large objects, such as a female human breast, it can be difficult to achieve a relatively uniform coverage of light fluence within the volume of interest when the position of the laser source is fixed. To circumvent this, researchers have proposed illumination schemes in which the relative position of the laser source and ultrasound probe is fixed, and bo...

  6. Spontaneous Coronary Dissection: “Live Flash” Optical Coherence Tomography Guided Angioplasty

    Science.gov (United States)

    Bento, Angela Pimenta; Fernandes, Renato Gil dos Santos Pinto; Neves, David Cintra Henriques Silva; Patrício, Lino Manuel Ribeiro; de Aguiar, José Eduardo Chambel

    2016-01-01

    Optical Coherence tomography (OCT) is a light-based imaging modality which shows tremendous potential in the setting of coronary imaging. Spontaneous coronary artery dissection (SCAD) is an infrequent cause of acute coronary syndrome (ACS). The diagnosis of SCAD is made mainly with invasive coronary angiography, although adjunctive imaging modalities such as computed tomography angiography, IVUS, and OCT may increase the diagnostic yield. The authors describe a clinical case of a young woman admitted with the diagnosis of ACS. The ACS was caused by SCAD detected in the coronary angiography and the angioplasty was guided by OCT. OCT use in the setting of SCAD has been already described and the true innovation in this case was this unique use of OCT. The guidance of angioplasty with live and short images was very useful as it allowed clearly identifying the position of the guidewires at any given moment without the use of prohibitive amounts of contrast. PMID:26989520

  7. Optical diffraction tomography using a digital micromirror device for stable measurements of 4-D refractive index tomography of cells

    CERN Document Server

    Shin, Seungwoo; Kim, Taeho; Yoon, Jonghee; Hong, Kihyun; Park, Jinah; Park, YongKeun

    2016-01-01

    Optical diffraction tomography (ODT) is an interferometric microscopy technique capable of measuring 3-D refractive index (RI) distribution of transparent samples. Multiple 2-D holograms of a sample illuminated with various angles are measured, from which 3-D RI map of the sample is reconstructed via the diffraction theory. ODT has been proved as a powerful tool for the study of biological cells, due to its non-invasiveness, label-free and quantitative imaging capability. Recently, our group has demonstrated that a digital micromirror device (DMD) can be exploited for fast and precise control of illumination beams for ODT. In this work, we systematically study the precision and stability of the ODT system equipped with a DMD and present measurements of 3-D and 4-D RI maps of various types of live cells including human red blood cells, white blood cells, hepatocytes, and HeLa cells. Furthermore, we also demonstrate the effective visualization of 3-D RI maps of live cells utilizing the measured information abou...

  8. Optical diffraction tomography using a digital micromirror device for stable measurements of 4D refractive index tomography of cells

    Science.gov (United States)

    Shin, Seungwoo; Kim, Kyoohyun; Kim, Taeho; Yoon, Jonghee; Hong, Kihyun; Park, Jinah; Park, YongKeun

    2016-03-01

    Optical diffraction tomography (ODT) is an interferometric microscopy technique capable of measuring 3-D refractive index (RI) distribution of transparent samples. Multiple 2-D holograms of a sample illuminated with various angles are measured, from which 3-D RI map of the sample is reconstructed via the diffraction theory. ODT has been proved as a powerful tool for the study of biological cells, due to its non-invasiveness, label-free and quantitative imaging capability. Recently, our group has demonstrated that a digital micromirror device (DMD) can be exploited for fast and precise control of illumination beams for ODT. In this work, we systematically study the precision and stability of the ODT system equipped with a DMD and present measurements of 3-D and 4-D RI maps of various types of live cells including human red blood cells, white blood cells, hepatocytes, and HeLa cells. Furthermore, we also demonstrate the effective visualization of 3-D RI maps of live cells utilizing the measured information about the values and gradient of RI tomograms.

  9. Three-dimensional correction of conduction velocity in the embryonic heart using integrated optical mapping and optical coherence tomography

    Science.gov (United States)

    Ma, Pei; Wang, Yves T.; Gu, Shi; Watanabe, Michiko; Jenkins, Michael W.; Rollins, Andrew M.

    2014-07-01

    Optical mapping (OM) of cardiac electrical activity conventionally collects information from a three-dimensional (3-D) surface as a two-dimensional (2-D) projection map. When applied to measurements of the embryonic heart, this method ignores the substantial and complex curvature of the heart surface, resulting in significant errors when calculating conduction velocity, an important electrophysiological parameter. Optical coherence tomography (OCT) is capable of imaging the 3-D structure of the embryonic heart and accurately characterizing the surface topology. We demonstrate an integrated OCT/OM imaging system capable of simultaneous conduction mapping and 3-D structural imaging. From these multimodal data, we obtained 3-D activation maps and corrected conduction velocity maps of early embryonic quail hearts. 3-D correction eliminates underestimation bias in 2-D conduction velocity measurements, therefore enabling more accurate measurements with less experimental variability. The integrated system will also open the door to correlate the structure and electrophysiology, thereby improving our understanding of heart development.

  10. Development of novel high-speed en face optical coherence tomography system using KTN optical beam deflector

    Science.gov (United States)

    Ohmi, Masato; Fukuda, Akihiro; Miyazu, Jun; Ueno, Masahiro; Toyoda, Seiji; Kobayashi, Junya

    2015-02-01

    We developed a novel high-speed en face optical coherence tomography (OCT) system using a KTa1-xNbxO3 (KTN) optical beam deflector. Using the imaging system, fast scanning was performed at 200 kHz by the KTN beam deflector, while slow scanning was performed at 400 Hz by the galvanometer mirror. In a preliminary experiment, we obtained en face OCT images of a human fingerprint at 400 fps. This is the highest speed reported in time-domain en face OCT imaging and is comparable to the speed of swept-source OCT. A 3D-OCT image of a sweat gland was also obtained by our imaging system.

  11. Study of continuous-wave domain fluorescence diffuse optical tomography for quality control on agricultural produce

    Energy Technology Data Exchange (ETDEWEB)

    Nadhira, Vebi, E-mail: vebi@tf.itb.ac.id; Kurniadi, Deddy, E-mail: vebi@tf.itb.ac.id; Juliastuti, E., E-mail: vebi@tf.itb.ac.id; Sutiswan, Adeline, E-mail: vebi@tf.itb.ac.id [Instrumentation and Control Research Group, Faculty of Industrial Technology, Institute Technology of Bandung, Ganesha 10 40132 Bandung (Indonesia)

    2014-03-24

    The importance of monitoring the quality of vegetables and fruits is prosperity by giving a competitive advantage for producer and providing a more healthy food for consumer. Diffuse Optical Tomography (DOT) is offering the possibility to detect the internal defects of the agricultural produce quality. Fluorescence diffuse optical tomography (FDOT) is the development of DOT, offering the possibilities to improve spatial resolution and to contrast image. The purpose of this research is to compare FDOT and DOT in forward analysis with continuous wave approach. The scattering and absorbing parameters of potatoes are used to represent the real condition. The object was illuminated by the NIR source from some positions on the boundary of object. A set of NIR detector are placed on the peripheral position of the object to measure the intensity of propagated or emitted light. In the simulation, we varied a condition of object then we analyzed the sensitivity of forward problem. The result of this study shows that FDOT has a better sensitivity than DOT and a better potential to monitor internal defects of agricultural produce because of the contrast value between optical and fluorescence properties of agricultural produce normal tissue and defects.

  12. Derivation of a Monte Carlo method for modeling heterodyne detection in optical coherence tomography systems

    DEFF Research Database (Denmark)

    Tycho, Andreas; Jørgensen, Thomas Martini; Andersen, Peter E.

    2002-01-01

    A Monte Carlo (MC) method for modeling optical coherence tomography (OCT) measurements of a diffusely reflecting discontinuity emb edded in a scattering medium is presented. For the first time to the authors' knowledge it is shown analytically that the applicability of an MC approach to this opti......A Monte Carlo (MC) method for modeling optical coherence tomography (OCT) measurements of a diffusely reflecting discontinuity emb edded in a scattering medium is presented. For the first time to the authors' knowledge it is shown analytically that the applicability of an MC approach...... to this optical geometry is firmly justified, because, as we show, in the conjugate image plane the field reflected from the sample is delta-correlated from which it follows that the heterodyne signal is calculated from the intensity distribution only. This is not a trivial result because, in general, the light...... focused beam, and it is shown that in free space the full three-dimensional intensity distribution of a Gaussian beam is obtained. The OCT signal and the intensity distribution in a scattering medium have been obtained for several geometries with the suggested MC method; when this model and a recently...

  13. In Vivo Near Infrared Virtual Intraoperative Surgical Photoacoustic Optical Coherence Tomography

    Science.gov (United States)

    Lee, Donghyun; Lee, Changho; Kim, Sehui; Zhou, Qifa; Kim, Jeehyun; Kim, Chulhong

    2016-01-01

    Since its first implementation in otolaryngological surgery nearly a century ago, the surgical microscope has improved the accuracy and the safety of microsurgeries. However, the microscope shows only a magnified surface view of the surgical region. To overcome this limitation, either optical coherence tomography (OCT) or photoacoustic microscopy (PAM) has been independently combined with conventional surgical microscope. Herein, we present a near-infrared virtual intraoperative photoacoustic optical coherence tomography (NIR-VISPAOCT) system that combines both PAM and OCT with a conventional surgical microscope. Using optical scattering and absorption, the NIR-VISPAOCT system simultaneously provides surgeons with real-time comprehensive biological information such as tumor margins, tissue structure, and a magnified view of the region of interest. Moreover, by utilizing a miniaturized beam projector, it can back-project 2D cross-sectional PAM and OCT images onto the microscopic view plane. In this way, both microscopic and cross-sectional PAM and OCT images are concurrently displayed on the ocular lens of the microscope. To verify the usability of the NIR-VISPAOCT system, we demonstrate simulated surgeries, including in vivo image-guided melanoma resection surgery and in vivo needle injection of carbon particles into a mouse thigh. The proposed NIR-VISPAOCT system has potential applications in neurosurgery, ophthalmological surgery, and other microsurgeries. PMID:27731390

  14. Prospectively electrocardiogram-triggered high-pitch spiral acquisition coronary computed tomography angiography for assessment of biodegradable vascular scaffold expansion: Comparison with optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    D’Alfonso, Maria Grazia [Interventional Cardiology Unit University Of Florence, Heart and Vessels department, AOU Careggi, Florence (Italy); Mattesini, Alessio, E-mail: amattesini@gmail.com [Interventional Cardiology Unit University Of Florence, Heart and Vessels department, AOU Careggi, Florence (Italy); Meucci, Francesco [Interventional Cardiology Unit University Of Florence, Heart and Vessels department, AOU Careggi, Florence (Italy); Acquafresca, Manlio [Radiology Unit 4, Radiology Department, AOU Careggi, Florence (Italy); Gensini, Gian Franco; Valente, Serafina [Interventional Cardiology Unit University Of Florence, Heart and Vessels department, AOU Careggi, Florence (Italy)

    2014-11-15

    BVS polymeric struts are transparent to the light so that the vessel wall contour can be easily visualized using optical coherence tomography (OCT). Therefore OCT represents a unique tool for both the evaluation of the resorption process and for the assessment of acute BVS mechanical failure. Similarly, the metal-free struts allow unrestricted coronary computed tomography angiography (CCTA), thus this non invasive method might become the gold standard for a non invasive assessment of BVS. In this case we show the ability of CCTA, performed with a low X-Ray dose, to provide a good evaluation of scaffold expansion. The quantitative measurements were in agreement with those obtained with OCT.

  15. Innovation and fusion of x-ray and optical tomography for mouse studies of breast cancer

    Science.gov (United States)

    Wang, Ge; Cong, Wenxiang; Yang, Qingsong; Pian, Qi; Zhu, Shouping; Liang, Jimin; Barroso, Margarida; Intes, Xavier

    2016-10-01

    For early detection and targeted therapy, receptor expression profiling is instrumental to classifying breast cancer into sub-groups. In particular, human epidermal growth factor receptor 2 (HER2) expression has been shown to have both prognostic and predictive values. Recently, an increasingly more complex view of HER2 in breast cancer has emerged from genome sequencing that highlights the role of inter- and intra-tumor heterogeneity in therapy resistance. Studies on such heterogeneity demand high-content, high-resolution functional and molecular imaging in vivo, which cannot be achieved using any single imaging tool. Clearly, there is a critical need to develop a multimodality approach for breast cancer imaging. Since 2006, grating-based x-ray imaging has been developed for much-improved x-ray images. In 2014, the demonstration of fluorescence molecular tomography (FMT) guided by x-ray grating-based micro-CT was reported with encouraging results and major drawbacks. In this paper, we propose to integrate grating-based x-ray tomography (GXT) and high-dimensional optical tomography (HOT) into the first-of-its-kind truly-fused GXT-HOT (pronounced as "Get Hot") system for imaging of breast tumor heterogeneity, HER2 expression and dimerization, and therapeutic response. The primary innovation lies in developing a brand-new high-content, high-throughput x-ray optical imager based on several contemporary techniques to have MRI-type soft tissue contrast, PET-like sensitivity and specificity, and micro-CT-equivalent resolution. This system consists of two orthogonal x-ray Talbot-Lau interferometric imaging chains and a hyperspectral time-resolved single-pixel optical imager. Both the system design and pilot results will be reported in this paper, along with relevant issues under further investigation.

  16. Reproducibility of Perfusion Parameters of Optic Disc and Macula in Rhesus Monkeys by Optical Coherence Tomography Angiography

    Institute of Scientific and Technical Information of China (English)

    Jing Li; Yi-Quan Yang; Di-Ya Yang; Xiang-Xiang Liu; Yun-Xiao Sun; Shi-Fei Wei; Ning-Li Wang

    2016-01-01

    Background:Optical coherence tomography (OCT) angiography is a novel technique by which we can detect the local perfusion of fundus directly.The aim of this study was to evaluate the reproducibility of optic disc and macular flow perfusion parameters in rhesus monkeys using OCT angiography.Methods:Eighteen healthy monkeys (18 eyes) were subjected to optic disc and macula flow index measurements via a high-speed and high-resolution spectral-domain OCT XR Avanti with a split-spectrum amplitude de-correlation angiography algorithm.Right eye was imaged 3 times during the first examination and once during each of the two following examinations.The intra-visit and inter-visit intraclass correlation coefficients (ICCs) were both determined.Results:The average flow indices of the four optic disc area layers were 0.171 ± 0.009 (optic nerve head),0.015 ± 0.004 (vitreous),0.052 ± 0.009 (radial peripapillary capillary),and 0.167 ± 0.011 (choroid).Average flow indices of the four macula area layers were 0.044 ± 0.011 (superficial retina),0.036 ± 0.011 (deep retina),0.016 ± 0.009 (outer retina),and 0.155 ± 0.013 (choroid).Intra-visit (ICC value:0.821-0.954) and inter-visit (ICC value:0.844-0.899) repeatability were both high.Conclusions:The study is about the reproducibility of optic disc and macular perfusion parameters as measured by OCT angiography in healthy rhesus monkeys.Flow index measurement reproducibility is high for both the optic disc and macula of normal monkey eyes.OCT angiography might be a useful technique to assess changes when examining monkeys with experimental ocular diseases.

  17. Neurofibromatosis: an update of ophthalmic characteristics and applications of optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Abdolrahimzadeh B

    2016-05-01

    Full Text Available Barmak Abdolrahimzadeh,1 Domenica Carmen Piraino,2 Giorgio Albanese,2 Filippo Cruciani,2 Siavash Rahimi3 1Polimed Beltramelli Medical Center, Rome, Italy; 2Section of Ophthalmology, Department of Sense Organs, University of Rome “Sapienza”, Rome, Italy; 3Pathology Centre, Queen Alexandra Hospital, Portsmouth, UK Abstract: Neurofibromatosis (NF is a multisystem disorder and tumor predisposition syndrome caused by genetic mutation on chromosome 17-17q11.2 in NF type 1 (NF1, and on chromosome 22-22q12.2 in NF type 2. The disorder is characterized by considerable heterogeneity of clinical expression. NF1 is the form with the most characteristic ocular manifestations. Lisch nodules of the iris are among the well-known diagnostic criteria for the disease. Glaucoma and associated globe enlargement have been described in a significant proportion of patients with NF1 and orbital–facial involvement. Optic nerve glioma may cause strabismus and proptosis, and palpebral neurofibroma may reach considerable size and occasionally show malignant transformation. Near infrared reflectance has greatly contributed to enhancing our knowledge on choroidal alterations in NF1. Indeed, some authors have proposed to include these among the diagnostic criteria. Optical coherence tomography has given new insight on retinal alterations and is a noninvasive tool in the management of optic nerve gliomas in children. Ocular manifestations in NF type 2 can range from early-onset cataracts in up to 80% of cases to optic nerve hamartomas and combined pigment epithelial and retinal hamartomas. Keywords: neurofibromatosis, ophthalmic, optical coherence tomography, infrared reflectance, choroideal nodules, Lisch nodules

  18. Volumetric Diffuse Optical Tomography for Small Animals Using a CCD-Camera-Based Imaging System

    Directory of Open Access Journals (Sweden)

    Zi-Jing Lin

    2012-01-01

    Full Text Available We report the feasibility of three-dimensional (3D volumetric diffuse optical tomography for small animal imaging by using a CCD-camera-based imaging system with a newly developed depth compensation algorithm (DCA. Our computer simulations and laboratory phantom studies have demonstrated that the combination of a CCD camera and DCA can significantly improve the accuracy in depth localization and lead to reconstruction of 3D volumetric images. This approach may present great interests for noninvasive 3D localization of an anomaly hidden in tissue, such as a tumor or a stroke lesion, for preclinical small animal models.

  19. Monitoring the gingival regeneration after aesthetic surgery with optical coherence tomography

    Science.gov (United States)

    Fernandes, Luana O.; Graça, Natalia D. R. L.; Melo, Luciana S. A.; Silva, Claudio H. V.; Gomes, Anderson S. L.

    2016-02-01

    The aim of this study was to use the Optical Coherence Tomography (OCT) technique working in spectral domain (Swept Source OCT at 1325 nm, Thorlabs, New Jersey, USA) to monitor the tissue repair in patients undergoing periodontal plastic surgery. The evaluations were done over a period of 60 days. It was observed that 15 days after periodontal surgery the gum was still in different healing process as compared to the observation after 60 days. Thus it is clear that, despite some technical limitations, the OCT is an efficient method in the evaluation of regeneration gingival.

  20. Optical coherence tomography following percutaneous coronary intervention with Excimer laser coronary atherectomy

    Energy Technology Data Exchange (ETDEWEB)

    Rawlins, John, E-mail: john.rawlins@doctors.net.uk; Talwar, Suneel; Green, Mark; O’Kane, Peter

    2014-01-15

    The indications for Excimer laser coronary atherectomy (ELCA) have been refined in modern interventional practice. With the expanding role for optical coherence tomography (OCT) providing high-resolution intra-coronary imaging, this article examines the appearance of the coronary lumen after ELCA. Each indication for ELCA is discussed and illustrated with a clinical case, followed by detailed analysis of the OCT imaging pre and post ELCA. The aim of the article is to provide information to interventional cardiologists to facilitate decision making during PCI, when ELCA has been used as part of the interventional strategy.

  1. Quantum optical coherence tomography using three time-energy entangled photons

    Science.gov (United States)

    Lopez-Mago, Dorilian; Burguete, Arturo; Campos, Eernesto

    2016-09-01

    Quantum Optical Coherence Tomography can achieve a greater image resolution compared to its classical counterpart, due to the entanglement of the photon pairs. Following the idea that higher the number of entangled photons, higher the resolution, we study the physical underpinnings that appear when using photon triplets. Unlike the usual Hong-Ou-Mandel interferometer used for QOCT, a much simpler implementation in the form of a Michelson interferometer is used in this work. We find that axial resolution can be improved by a factor of four. Additionally, we provide the numerical method to reconstruct the image given the triple coincidence rate.

  2. Photoinduced cell morphology alterations quantified within adipose tissues by spectral optical coherence tomography.

    Science.gov (United States)

    Yanina, Irina Yu; Trunina, Natalia A; Tuchin, Valery V

    2013-11-01

    Morphological changes of the adipose tissue at phototreatment are studied in vitro using optical coherence tomography. The 200 to 600 μm fat tissue slices are used in the experiments. The observed change in the tissue structure was associated with fat cell lipolysis and destruction caused by the photodynamic effect. It is found that overall heating of a sample from room to physiological temperature leads to deeper and faster morphology tissue changes if other processing conditions are kept constant. These data support the hypothesis that photodynamic/photothermal treatment induces fat cell lipolysis during some period after treatment.

  3. Resolving directional ambiguity in dynamic light scattering-based transverse motion velocimetry in optical coherence tomography

    Science.gov (United States)

    Huang, Brendan K.; Choma, Michael A.

    2014-01-01

    Dynamic Light Scattering-based Optical Coherence Tomography approaches have been successfully implemented to measure total transverse (xy) flow speed, but are unable to resolve directionality. We propose a method to extract directional velocity in the transverse plane by introducing a variable scan bias to our system. Our velocity estimation, which yields the directional velocity component along the scan axis, is also independent of any point spread function calibration. By combining our approach with Doppler velocimetry, we show three-component velocimetry that is appropriately dependent on latitudinal and longitudinal angle. PMID:24487855

  4. Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography

    Science.gov (United States)

    Heidari, Andrew E.; Moghaddam, Samer; Troung, Kimberly K.; Chou, Lidek; Genberg, Carl; Brenner, Matthew; Chen, Zhongping

    2015-12-01

    Biofilm formation has been linked to ventilator-associated pneumonia, which is a prevalent infection in hospital intensive care units. Currently, there is no rapid diagnostic tool to assess the degree of biofilm formation or cellular biofilm composition. Optical coherence tomography (OCT) is a minimally invasive, nonionizing imaging modality that can be used to provide high-resolution cross-sectional images. Biofilm deposited in critical care patients' endotracheal tubes was analyzed in vitro. This study demonstrates that OCT could potentially be used as a diagnostic tool to analyze and assess the degree of biofilm formation and extent of airway obstruction caused by biofilm in endotracheal tubes.

  5. Optical Coherence Tomography Imaging of Choroidal Abnormalities in Neurofibromatosis Type 1

    Directory of Open Access Journals (Sweden)

    Shinji Makino

    2013-01-01

    Full Text Available We report a case of neurofibromatosis type 1 (NF1 examined by infrared fundus autofluorescence (IR-FAF and optical coherence tomography (OCT to characterize the associated choroidal abnormalities. The conventional ophthalmoscopic findings were unremarkable. However, IR-FAF revealed multiple bright patchy lesions in the choroid of the posterior pole, in both eyes. OCT demonstrated irregular hyperreflectivity at the sites of these lesions. Patients with NF1 may have typical choroidal lesions that are visible on IR-FAF, which can be confirmed through OCT.

  6. Dual-modality photothermal optical coherence tomography and magnetic-resonance imaging of carbon nanotubes.

    Science.gov (United States)

    Tucker-Schwartz, Jason M; Hong, Tu; Colvin, Daniel C; Xu, Yaqiong; Skala, Melissa C

    2012-03-01

    We demonstrate polyethylene-glycol-coated single-walled carbon nanotubes (CNTs) as contrast agents for both photothermal optical coherence tomography (OCT) and magnetic-resonance imaging (MRI). Photothermal OCT was accomplished with a spectral domain OCT system with an amplitude-modulated 750 nm pump beam using 10 mW of power, and T(2) MRI was achieved with a 4.7 T animal system. Photothermal OCT and T(2) MRI achieved sensitivities of nanomolar concentrations to CNTs dispersed in amine-terminated polyethylene glycol, thus establishing the potential for dual-modality molecular imaging with CNTs.

  7. Dual Modality Photothermal Optical Coherence Tomography and Magnetic Resonance Imaging of Carbon Nanotubes

    OpenAIRE

    Tucker – Schwartz, Jason M.; Hong, Tu; Colvin, Daniel C.; Xu, Yaqiong; Skala, Melissa C.

    2012-01-01

    We demonstrate polyethylene glycol coated single-walled carbon nanotubes (CNTs) as contrast agents for both photothermal optical coherence tomography (OCT) and magnetic resonance imaging. Photothermal OCT was accomplished with a spectral domain OCT system with an amplitude modulated 750 nm pump beam using 10 mW of power, and T2 MR imaging was achieved with a 4.7 T animal system. Photothermal OCT and T2 MR imaging achieved sensitivities of nM concentrations to CNTs dispersed in amine terminate...

  8. Mechanisms of Very Late Drug-Eluting Stent Thrombosis Assessed by Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Taniwaki, Masanori; Radu, Maria D; Zaugg, Serge

    2016-01-01

    suitable for analysis. VLST occurred at a median of 4.7 years (interquartile range, 3.1-7.5 years). An underlying putative cause by optical coherence tomography was identified in 98% of cases. The most frequent findings were strut malapposition (34.5%), neoatherosclerosis (27.6%), uncovered struts (12.1...... of malapposed or uncovered struts (3.40 mm; 95% confidence interval, 2.55-4.25; versus 1.29 mm; 95% confidence interval, 0.81-1.77; P

  9. Evaluation of Retinal Changes Using Optical Coherence Tomography in a Pediatric Case of Susac Syndrome

    Directory of Open Access Journals (Sweden)

    Mehmet Kola

    2017-01-01

    Full Text Available Susac syndrome is a rare occlusive vasculopathy affecting the retina, inner ear and brain. The cause is unknown, although it generally affects young women. This syndrome can be difficult to diagnose because its signs can only be revealed by detailed examination. These signs are not always concomitant, but may appear at different times. This report describes a pediatric case who was diagnosed with Susac syndrome when retinal lesions were identified in the inactive period with the help of optical coherence tomography (OCT. The purpose of this case report is to emphasize the importance of OCT in clarifying undefined retinal changes in Susac syndrome.

  10. Real-time dispersion-compensated image reconstruction for compressive sensing spectral domain optical coherence tomography.

    Science.gov (United States)

    Xu, Daguang; Huang, Yong; Kang, Jin U

    2014-09-01

    In this work, we propose a novel dispersion compensation method that enables real-time compressive sensing (CS) spectral domain optical coherence tomography (SD OCT) image reconstruction. We show that dispersion compensation can be incorporated into CS SD OCT by multiplying the dispersion-correcting terms by the undersampled spectral data before CS reconstruction. High-quality SD OCT imaging with dispersion compensation was demonstrated at a speed in excess of 70 frames per s using 40% of the spectral measurements required by the well-known Shannon/Nyquist theory. The data processing and image display were performed on a conventional workstation having three graphics processing units.

  11. The early-stage diagnosis of albinic embryos by applying optical coherence tomography

    Science.gov (United States)

    Yang, Bor-Wen; Wang, Shih-Yuan; Wang, Yu-Yen; Cai, Jyun-Jhang; Chang, Chung-Hao

    2013-09-01

    Albinism is a kind of congenital disease of abnormal metabolism. Poecilia reticulata (guppy fish) is chosen as the model to study the development of albinic embryos as it is albinic, ovoviviparous and with short life period. This study proposed an imaging method for penetrative embryo investigation using optical coherence tomography. By imaging through guppy mother’s reproduction purse, we found the embryo’s eyes were the early-developed albinism features. As human’s ocular albinism typically appear at about four weeks old, it is the time to determine if an embryo will grow into an albino.

  12. Quantification of choroidal neovascularization vessel length using optical coherence tomography angiography

    Science.gov (United States)

    Gao, Simon S.; Liu, Li; Bailey, Steven T.; Flaxel, Christina J.; Huang, David; Li, Dengwang; Jia, Yali

    2016-07-01

    Quantification of choroidal neovascularization (CNV) as visualized by optical coherence tomography angiography (OCTA) may have importance clinically when diagnosing or tracking disease. Here, we present an automated algorithm to quantify the vessel skeleton of CNV as vessel length. Initial segmentation of the CNV on en face angiograms was achieved using saliency-based detection and thresholding. A level set method was then used to refine vessel edges. Finally, a skeleton algorithm was applied to identify vessel centerlines. The algorithm was tested on nine OCTA scans from participants with CNV and comparisons of the algorithm's output to manual delineation showed good agreement.

  13. Time-multiplexed structured illumination using a DMD for optical diffraction tomography

    CERN Document Server

    Lee, Kyeoreh; Kim, Geon; Shin, Seungwoo; Park, YongKeun

    2016-01-01

    We present a novel illumination control technique for optical diffraction tomography (ODT). Various spatial frequencies of beam illumination were controlled by displaying time-averaged sinusoidal patterns using a digital micromirror device (DMD). Compared to the previous method using binary Lee holograms, the present method eliminates unwanted diffracted beams which may deteriorate the image quality of the ODT. We demonstrated the capability of the present method by reconstructing three-dimensional refractive index (RI) distributions of various samples, with high RI sensitivity (\\sigma_\\Delta n = 3.15 +/- 10-4), and reconstructing 3-D RI tomograms of biological samples, which provided quantitative biochemical and morphological information about the samples.

  14. An elegant technique for ex vivo imaging in experimental research—Optical coherence tomography (OCT)

    DEFF Research Database (Denmark)

    Tschernig, T.; Thrane, Lars; Jørgensen, Thomas Martini

    2013-01-01

    Optical coherence tomography (OCT) is an elegant technology for imaging of tissues and organs and has been established for clinical use for around a decade. Thus, it is used in vivo but can also serve as a valuable ex vivo imaging tool in experimental research. Here, a brief overview is given...... with a focus on an ex vivo application of OCT. Image and video examples of freshly obtained murine lungs are included. The main advantage of OCT for ex vivo analysis is the non-contact, non-invasive, and non-destructive fast acquisition of a three-dimensional data set with micrometer-resolution....

  15. A Focal Chorioretinal Bartonella Lesion Analyzed by Optical Coherence Tomography Angiography.

    Science.gov (United States)

    Pichi, Francesco; Srivastava, Sunil K; Levinson, Ashleigh; Baynes, Kimberly M; Traut, Caitlyn; Lowder, Careen Y

    2016-06-01

    Neovascularization may be associated with cat-scratch neuroretinitis in the absence of retinal vascular occlusion. Bartonella organisms establish an intimate relationship with the vascular endothelium, causing angioproliferative lesions, which might represent a dedicated pathogenic strategy for expanding the bacterial host cell habitat. In the eye, pathological angiogenesis caused by Bartonella has been described as peripapillary or macular choroidal neovascularization, but the presence of neovascularization within foci of chorioretinitis has never before been reported. The authors present a case of Bartonella chorioretinitis in which optical coherence tomography angiography, by detecting erythrocyte motion, was able to identify neovessels inside the infectious focus. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:585-588.].

  16. In vivo quantification of cochlin in glaucomatous DBA/2J mice using optical coherence tomography

    Science.gov (United States)

    Wang, Jianhua; Aljohani, Ayman; Carreon, Teresia; Gregori, Giovanni; Bhattacharya, Sanjoy K.

    2015-01-01

    The expression of cochlin in the trabecular meshwork (TM) precedes the clinical glaucoma symptoms in DBA/2J mice. The ability to quantify cochlin in the local tissue (TM) offers potential diagnostic and prognostic values. We present two (spectroscopic and magnetomotive) optical coherence tomography (OCT) approaches for in vivo cochlin quantification in a periodic manner. The cochlin-antibody OCT signal remains stable for up to 24 hours as seen at 3.5 hours after injection allowing for repeated quantification in the living mouse eyes. PMID:26047051

  17. Colorectal neoplasm characterization based on swept-source optical coherence tomography

    Science.gov (United States)

    Lu, Chih-Wei; Chiu, Han-Mo; Sun, Chia-Wei

    2009-07-01

    Most of the colorectal cancer has grown from the adenomatous polyp. Adenomatous lesions have a well-documented relationship to colorectal cancer in previous studies. Thus, to detect the morphological changes between polyp and tumor can allow early diagnosis of colorectal cancer and simultaneous removal of lesions. In this paper, the various adenoma/carcinoma in-vitro samples are monitored by our swept-source optical coherence tomography (SS-OCT) system. The significant results indicate a great potential for early detection of colorectal adenomas based on the SS-OCT imaging.

  18. Imaging of human breast tissue using polarization sensitive optical coherence tomography

    Science.gov (United States)

    Verma, Y.; Gautam, M.; Divakar Rao, K.; Swami, M. K.; Gupta, P. K.

    2011-12-01

    We report a study on the use of polarization sensitive optical coherence tomography (PSOCT) for discriminating malignant (invasive ductal carcinoma), benign (fibroadenoma) and normal (adipocytes) breast tissue sites. The results show that while conventional OCT, that utilizes only the intensity of light back-scattered from tissue microstructures, is able to discriminate breast tissues as normal (adipocytes) and abnormal (malignant and benign) tissues, PS-OCT helps in discriminating between malignant and benign tissue sites also. The estimated values of birefringence obtained from the PSOCT imaging show that benign breast tissue samples have significantly higher birefringence as compared to the malignant tissue samples.

  19. Ultrahigh resolution optical coherence tomography with femtosecond Ti:sapphire laser and photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    XUE Ping; James G FUJIMOTO

    2008-01-01

    Optical coherence tomography (OCT) with ultrahigh axial resolution was achieved by the super-contin- uum generated by coupling femtosecond pulses from a commercial Ti :sapphire laser into an air-silica microstructure fiber. The visible spectrum of the super-continuum from 450 to 700 nm centered at 540 nm can be generated. A free-space axial OCT resolution of 0.64 IJm was achieved. The sensitivity of OCT system was 108 dB with incident light power 3 mW at sample, only 7dB below the theoretical limit. Subcellular OCT imaging was also demonstrated, showing great potential for biomedical application.

  20. Digital signal processor-based real-time optical Doppler tomography system.

    Science.gov (United States)

    Yan, Shikui; Piao, Daqing; Chen, Yueli; Zhu, Quing

    2004-01-01

    We present a real-time data-processing and display unit based on a custom-designed digital signal processor (DSP) module for imaging tissue structure and Doppler blood flow. The DSP module is incorporated into a conventional optical coherence tomography system. We also demonstrate the flexibility of embedding advanced Doppler processing algorithms in the DSP module. Two advanced velocity estimation algorithms previously introduced by us are incorporated in this DSP module. Experiments on Intralipid flow demonstrate that a pulsatile flow of several hundred pulses per minute can be faithfully captured in M-scan mode by this DSP system. In vivo imaging of a rat's abdominal blood flow is also presented.

  1. Morphological characterization of cells in concentrated suspensions using multispectral diffuse optical tomography.

    Science.gov (United States)

    Hajihashemi, Mohammad Reza; Li, Xiaoqi; Jiang, Huabei

    2012-10-01

    Based on a non-spherical model of particle scattering, we investigate the capabilities and limitations of a T-matrix based inverse algorithm to morphologically characterize cells in concentrated suspensions. Here the cells are modeled as randomly orientated spheroidal particles with homogenous dielectric properties and suspended in turbid media. The inverse algorithm retrieves the geometrical parameters and the concentration of cells simultaneously by inverting the reduced scattering coefficient spectra obtained from multispectral diffuse optical tomography (MS-DOT). Both round and spheroidal cells are tested and the role of multiple and higher order scattering of particles on the performance of the algorithm is evaluated using different concentrations of cells.

  2. Measurement of the refractive index of human teeth by optical coherence tomography

    Science.gov (United States)

    Meng, Zhuo; Yao, X. Steve; Yao, Hui; Liang, Yan; Liu, Tiegen; Li, Yanni; Wang, Guanhua; Lan, Shoufeng

    2009-05-01

    We describe a novel method based on optical coherence tomography (OCT) for the accurate measurement of the refractive index of in vitro human teeth. We obtain the refractive indices of enamel, dentin, and cementum to be 1.631+/-0.007, 1.540+/-0.013, and 1.582+/-0.010, respectively. The profile of the refractive index is readily obtained via an OCT B scan across a tooth. This method can be used to study the refractive index changes caused by dental decay and therefore has great potential for the clinical diagnosis of early dental caries.

  3. Non-invasive assessment of corneal crosslinking changes using polarization sensitive optical coherence tomography

    Science.gov (United States)

    Alonso-Caneiro, D.; Yamanari, M.; Fukuda, S.; Hoshi, S.; Nagase, S.; Oshika, T.; Yasuno, Y.; Collins, M.

    2013-03-01

    Collagen crosslinking (CXL) has shown promising results in the prevention of the progression of keratoconus and corneal ectasia. However, techniques for in vivo and in situ assessment of the treatment are limited. In this study, ex vivo porcine eyes were treated with a chemical CXL agent (glutaraldehyde), during which polarization sensitive optical coherence tomography (PS-OCT) recordings were acquired simultaneously to assess the sensitivity of the technique to assess changes in the cornea. The results obtained in this study suggest that PSOCT may be a suitable technique to measure CXL changes in situ and to assess the local changes in the treated region of the cornea.

  4. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    Science.gov (United States)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-03-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  5. A new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    Science.gov (United States)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-10-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) annihilation photon pair coincidence time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit of around 100 ps. On the other hand, modulation mechanisms of a material's optical properties as exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to study whether ionizing radiation can also produce fast modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5x10-6 is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the radiation source flux rate and average photon energy.

  6. Scanning laser optical computed tomography system for large volume 3D dosimetry

    Science.gov (United States)

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2017-04-01

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  7. Scanning laser optical computed tomography system for large volume 3D dosimetry.

    Science.gov (United States)

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2017-04-07

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  8. Novel electro-optical coupling technique for magnetic resonance-compatible positron emission tomography detectors.

    Science.gov (United States)

    Olcott, Peter D; Peng, Hao; Levin, Craig S

    2009-01-01

    A new magnetic resonance imaging (MRI)-compatible positron emission tomography (PET) detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL) diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs.

  9. Novel Electro-Optical Coupling Technique for Magnetic Resonance-Compatible Positron Emission Tomography Detectors

    Directory of Open Access Journals (Sweden)

    Peter D. Olcott

    2009-03-01

    Full Text Available A new magnetic resonance imaging (MRI-compatible positron emission tomography (PET detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs.

  10. A promising new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    Science.gov (United States)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-11-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to for the first time study whether ionizing radiation can produce modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5× {{10}-6} is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the detected event rate and average photon energy of the radiation source.

  11. Optical coherence tomography evaluation of retinal nerve fiber layer in longitudinally extensive transverse myelitis

    Directory of Open Access Journals (Sweden)

    Frederico C. Moura

    2011-02-01

    Full Text Available OBJECTIVE: To compare optical coherence tomography (OCT measurements on the retinal nerve fiber layer (RNFL of healthy controls and patients with longitudinally extensive transverse myelitis (LETM without previous optic neuritis. METHOD: Twenty-six eyes from 26 patients with LETM and 26 control eyes were subjected to automated perimetry and OCT for comparison of RNFL measurements. RESULTS: The mean deviation values from perimetry were significantly lower in patients with LETM than in controls (p<0.0001. RNFL measurements in the nasal quadrant and in the 3-o'clock segment were significantly smaller in LETM eyes than in controls. (p=0.04 and p=0.006, respectively. No significantly differences in other RNFL measurements were found. CONCLUSION: Patients with LETM may present localized RNFL loss, particularly on the nasal side of the optic disc, associated with slight visual field defects, even in the absence of previous episodes of optic neuritis. These findings emphasize the fact that patients with LETM may experience attacks of subclinical optic nerve damage.

  12. Doppler optical coherence microscopy and tomography applied to inner ear mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Page, Scott; Freeman, Dennis M. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Ghaffari, Roozbeh [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States)

    2015-12-31

    While it is clear that cochlear traveling waves underlie the extraordinary sensitivity, frequency selectivity, and dynamic range of mammalian hearing, the underlying micromechanical mechanisms remain unresolved. Recent advances in low coherence measurement techniques show promise over traditional laser Doppler vibrometry and video microscopy, which are limited by low reflectivities of cochlear structures and restricted optical access. Doppler optical coherence tomography (DOCT) and Doppler optical coherence microscopy (DOCM) both utilize a broadband source to limit constructive interference of scattered light to a small axial depth called a coherence gate. The coherence gate can be swept axially to image and measure sub-nanometer motions of cochlear structures throughout the cochlear partition. The coherence gate of DOCT is generally narrower than the confocal gate of the focusing optics, enabling increased axial resolution (typically 15 μm) within optical sections of the cochlear partition. DOCM, frequently implemented in the time domain, centers the coherence gate on the focal plane, achieving enhanced lateral and axial resolution when the confocal gate is narrower than the coherence gate. We compare these two complementary systems and demonstrate their utility in studying cellular and micromechanical mechanisms involved in mammalian hearing.

  13. A partial reconstruction scheme for continuous wave diffuse optical tomography with reflection geometry.

    Science.gov (United States)

    Patra, Rusha; Dutta, Pranab K

    2015-01-01

    Image quality and photon measurement with good SNR (signal to noise ratio) in continuous wave diffuse optical tomography depend on the source detector density and sensitivity of photo detector. For large volume objects, it is difficult to obtain detectable light intensity with good SNR over the whole boundary. As an alternative, instead of the full boundary, the measurements are taken over a semi circle as in reflection geometry and a partial reconstruction scheme for the same is proposed in this paper. The cross-sectional optical parameters are reconstructed for different half of the sample with modified boundary conditions and finally the average of all the reconstructions are considered as the final reconstructed image. Simulation and experimental results have been illustrated to validate the proposed method. The main advantage of this scheme is to improve signal to noise ratio which controls the quality of reconstruction in actual phantoms. The use of continuous wave measurement makes the system cost effective as well.

  14. Online monitoring of printed electronics by Spectral-Domain Optical Coherence Tomography

    KAUST Repository

    Alarousu, Erkki

    2013-03-28

    Spectral-Domain Optical Coherence Tomography (SD-OCT) is an optical method capable of 3D imaging of object\\'s internal structure with micron-scale resolution. Modern SD-OCT tools offer the speed capable of online monitoring of printed devices. This paper demonstrates the use of SD-OCT in a simulated roll-to-roll (R2R) process through monitoring some structural properties of moving screen printed interdigitated electrodes. It is shown that structural properties can be resolved for speeds up to ca. 1m/min, which is the first step towards application of this method in real manufacturing processes, including roll-to-roll (R2R) printing.

  15. Morphology and epidermal thickness of normal skin imaged by optical coherence tomography

    DEFF Research Database (Denmark)

    Mogensen, Mette; Morsy, Hanan A.; Thrane, Lars;

    2008-01-01

    Background: Optical coherence tomography (OCT) is an optical imaging technology with a potential in the non-invasive diagnosis of skin cancer. To identify skin pathologies using OCT, it is of prime importance to establish baseline morphological features of normal skin. Aims: The aim of this study....... In glabrous skin the stratum corneum is visible. Children had larger ET (p skin-type-related differences in ET were found. Conclusion: This study contributes to understanding OCT and PS-OCT images of normal skin and indicates that OCT...... is to describe normal skin morphology using OCT and polarization-sensitive OCT (PS-OCT), which is a way of representing birefringent tissue such as collagen in OCT images. Anatomical locations in 20 healthy volunteers were imaged, and epidermal thickness (ET) was measured and compared to age, gender and skin...

  16. Parallel programming of gradient-based iterative image reconstruction schemes for optical tomography.

    Science.gov (United States)

    Hielscher, Andreas H; Bartel, Sebastian

    2004-02-01

    Optical tomography (OT) is a fast developing novel imaging modality that uses near-infrared (NIR) light to obtain cross-sectional views of optical properties inside the human body. A major challenge remains the time-consuming, computational-intensive image reconstruction problem that converts NIR transmission measurements into cross-sectional images. To increase the speed of iterative image reconstruction schemes that are commonly applied for OT, we have developed and implemented several parallel algorithms on a cluster of workstations. Static process distribution as well as dynamic load balancing schemes suitable for heterogeneous clusters and varying machine performances are introduced and tested. The resulting algorithms are shown to accelerate the reconstruction process to various degrees, substantially reducing the computation times for clinically relevant problems.

  17. Broadband Fourier domain mode-locked laser for optical coherence tomography at 1060 nm

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

    2012-01-01

    Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human posterior eye segment (retina, choroid, sclera) due to low absorption in water and deep penetration into the tissue. Rapidly tunable light sources, such as Fourier domain mode-locked (FDML) lasers...... implemented an FDML laser using a new SOA featuring broad gain bandwidth and high output power. The output spectrum coincides with the wavelength range of minimal water absorption, making the light source ideal for OCT imaging of the posterior eye segment. With a moderate SOA current (270 mA) we achieve up......, enable acquisition of densely sampled three-dimensional datasets covering a wide field of view. However, semiconductor optical amplifiers (SOAs)-the typical laser gain media for swept sources-for the 1060nm band could until recently only provide relatively low output power and bandwidth. We have...

  18. Three-dimensional surface reconstruction within noncontact diffuse optical tomography using structured light.

    Science.gov (United States)

    Baum, Kirstin; Hartmann, Raimo; Bischoff, Tobias; Oelerich, Jan O; Finkensieper, Stephan; Heverhagen, Johannes T

    2012-12-01

    A main field in biomedical optics research is diffuse optical tomography, where intensity variations of the transmitted light traversing through tissue are detected. Mathematical models and reconstruction algorithms based on finite element methods and Monte Carlo simulations describe the light transport inside the tissue and determine differences in absorption and scattering coefficients. Precise knowledge of the sample's surface shape and orientation is required to provide boundary conditions for these techniques. We propose an integrated method based on structured light three-dimensional (3-D) scanning that provides detailed surface information of the object, which is usable for volume mesh creation and allows the normalization of the intensity dispersion between surface and camera. The experimental setup is complemented by polarization difference imaging to avoid overlaying byproducts caused by inter-reflections and multiple scattering in semitransparent tissue.

  19. Analog CMOS design for optical coherence tomography signal detection and processing.

    Science.gov (United States)

    Xu, Wei; Mathine, David L; Barton, Jennifer K

    2008-02-01

    A CMOS circuit was designed and fabricated for optical coherence tomography (OCT) signal detection and processing. The circuit includes a photoreceiver, differential gain stage and lock-in amplifier based demodulator. The photoreceiver consists of a CMOS photodetector and low noise differential transimpedance amplifier which converts the optical interference signal into a voltage. The differential gain stage further amplifies the signal. The in-phase and quadrature channels of the lock-in amplifier each include an analog mixer and switched-capacitor low-pass filter with an external mixer reference signal. The interferogram envelope and phase can be extracted with this configuration, enabling Doppler OCT measurements. A sensitivity of -80 dB is achieved with faithful reproduction of the interferometric signal envelope. A sample image of finger tip is presented.

  20. Diagnostic value of optical coherence tomography for intracranial pressure in idiopathic intracranial hypertension

    DEFF Research Database (Denmark)

    Skau, M; Yri, H; Sander, B;

    2013-01-01

    , and 20 healthy controls. Investigations included measurement of peripapillary retinal nerve fiber layer thickness (RNFLT) and total retinal thickness (RT), automated visual field testing, and measurement of CSF opening pressure. An OCT elevation diagram was developed as a new diagnostic tool....... The diagnostic ability of OCT as a marker of increased ICP (> 25 cmH(2)O) was investigated using multiple regression and receiver operating characteristic (ROC) curves. RESULTS: OCT elevation diagrams showed that in 60 % of patients newly diagnosed with IIH and in 10 % of patients with long-term IIH, 50...... optic atrophy. The aim of this study was to evaluate the diagnostic value of optical coherence tomography (OCT) as a marker for CSF opening pressure in patients with idiopathic intracranial hypertension (IIH). METHODS: We conducted a case-control study of 20 newly diagnosed, 21 long-term IIH patients...

  1. Lensed fiber probes designed as an alternative to bulk probes in optical coherence tomography.

    Science.gov (United States)

    Ryu, Seon Young; Choi, Hae Young; Na, Jihoon; Choi, Woo June; Lee, Byeong Ha

    2008-04-01

    We demonstrate a compact all-fiber sampling probe for an optical coherence tomography (OCT) system. By forming a focusing lens directly on the tip of an optical fiber, a compact sampling probe could be implemented. To simultaneously achieve a sufficiently long working distance and a good lateral resolution, we employed a large-mode area photonic crystal fiber (PCF) and a coreless silica fiber (CSF) of the same diameters. A working distance of up to 1270 microm, a 3 dB distance range of 2210 microm, and a transverse resolution of 14.2 microm were achieved with the implemented PCF lensed fiber; these values are comparable to those obtainable with a conventional objective lens having an NA of 0.25 (10 x). The performance of the OCT system equipped with the proposed PCF lensed fiber is presented by showing the OCT images of a rat finger as a biological sample and a pearl as an in-depth sample.

  2. Three-dimensional surface reconstruction within noncontact diffuse optical tomography using structured light

    Science.gov (United States)

    Baum, Kirstin; Hartmann, Raimo; Bischoff, Tobias; Oelerich, Jan O.; Finkensieper, Stephan; Heverhagen, Johannes T.

    2012-12-01

    A main field in biomedical optics research is diffuse optical tomography, where intensity variations of the transmitted light traversing through tissue are detected. Mathematical models and reconstruction algorithms based on finite element methods and Monte Carlo simulations describe the light transport inside the tissue and determine differences in absorption and scattering coefficients. Precise knowledge of the sample's surface shape and orientation is required to provide boundary conditions for these techniques. We propose an integrated method based on structured light three-dimensional (3-D) scanning that provides detailed surface information of the object, which is usable for volume mesh creation and allows the normalization of the intensity dispersion between surface and camera. The experimental setup is complemented by polarization difference imaging to avoid overlaying byproducts caused by inter-reflections and multiple scattering in semitransparent tissue.

  3. Optical coherence tomography imaging of the basal ganglia: feasibility and brief review

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, W. O. Contreras; Ângelos, J. S. [Divisão de Neurocirurgia Funcional, Departamento de Neurologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Martinez, R. C. R. [Laboratório de Neuromodulação e Dor Experimental, Hospital Sírio-Libanes, São Paulo, SP (Brazil); Takimura, C. K. [Instituto do Coração, Universidade de São Paulo, São Paulo, SP (Brazil); Teixeira, M. J. [Divisão de Neurocirurgia Funcional, Departamento de Neurologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Lemos, P. A. Neto [Instituto do Coração, Universidade de São Paulo, São Paulo, SP (Brazil); Fonoff, E. T., E-mail: fonoffet@usp.br [Divisão de Neurocirurgia Funcional, Departamento de Neurologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

    2015-09-29

    Optical coherence tomography (OCT) is a promising medical imaging technique that uses light to capture real-time cross-sectional images from biological tissues in micrometer resolution. Commercially available optical coherence tomography systems are employed in diverse applications, including art conservation and diagnostic medicine, notably in cardiology and ophthalmology. Application of this technology in the brain may enable distinction between white matter and gray matter, and obtainment of detailed images from within the encephalon. We present, herein, the in vivo implementation of OCT imaging in the rat brain striatum. For this, two male 60-day-old rats (Rattus norvegicus, Albinus variation, Wistar) were stereotactically implanted with guide cannulas into the striatum to guide a 2.7-French diameter high-definition OCT imaging catheter (Dragonfly™, St. Jude Medical, USA). Obtained images were compared with corresponding histologically stained sections to collect imaging samples. A brief analysis of OCT technology and its current applications is also reported, as well as intra-cerebral OCT feasibility on brain mapping during neurosurgical procedures.

  4. In vivo noninvasive measurement of preprandial and postprandial blood glucose using optical coherence tomography

    Science.gov (United States)

    Zhang, Ying; Zhang, Xiyang; Li, Zhifang; Li, Hui

    2016-10-01

    Blood glucose concentration measurement is essential for the diagnosis and treatment of diabetes. However, conventional glucose measurement methods are invasive and not suitable for real-time monitoring. This study demonstrated a noninvasive blood glucose measurement method using optical coherence tomography to image human lip in vivo. Optical coherence tomography (OCT) is a noninvasive and depth-resolved technique capable of acquiring tissue structure images in real time. Human lip has very thin skin and is full of blood vessels, which is appropriate for noninvasive glucose measurement. To verify the feasibility of OCT for glucose concentration monitoring, two groups of OCT imaging data were obtained from human lips of normal people. In one group, OCT images of lip were acquired from people on an empty stomach. In the other group, the same sites of lip were observed by OCT 2 hours after breakfast. Evident differences were found from two groups of OCT images that correspond to preprandial glucose and 2- hour postprandial glucose, respectively. The relationship between OCT image and blood glucose concentration was investigated. The result indicates that OCT possesses considerable prospects in terms of noninvasive blood glucose measurement.

  5. Study on image feature extraction and classification for human colorectal cancer using optical coherence tomography

    Science.gov (United States)

    Huang, Shu-Wei; Yang, Shan-Yi; Huang, Wei-Cheng; Chiu, Han-Mo; Lu, Chih-Wei

    2011-06-01

    Most of the colorectal cancer has grown from the adenomatous polyp. Adenomatous lesions have a well-documented relationship to colorectal cancer in previous studies. Thus, to detect the morphological changes between polyp and tumor can allow early diagnosis of colorectal cancer and simultaneous removal of lesions. OCT (Optical coherence tomography) has been several advantages including high resolution and non-invasive cross-sectional image in vivo. In this study, we investigated the relationship between the B-scan OCT image features and histology of malignant human colorectal tissues, also en-face OCT image and the endoscopic image pattern. The in-vitro experiments were performed by a swept-source optical coherence tomography (SS-OCT) system; the swept source has a center wavelength at 1310 nm and 160nm in wavelength scanning range which produced 6 um axial resolution. In the study, the en-face images were reconstructed by integrating the axial values in 3D OCT images. The reconstructed en-face images show the same roundish or gyrus-like pattern with endoscopy images. The pattern of en-face images relate to the stages of colon cancer. Endoscopic OCT technique would provide three-dimensional imaging and rapidly reconstruct en-face images which can increase the speed of colon cancer diagnosis. Our results indicate a great potential for early detection of colorectal adenomas by using the OCT imaging.

  6. Spectral domain optical coherence tomography documented rapid resolution of pseudophakic cystoid macular edema with topical difluprednate

    Directory of Open Access Journals (Sweden)

    Chalam KV

    2012-01-01

    Full Text Available KV Chalam, Vijay Khetpal, Chirag J PatelDepartment of Ophthalmology, University of Florida Jacksonville, FL, USAIntroduction: Pseudophakic cystoid macular edema is a common cause of poor vision after cataract surgery, and topical corticosteroids and nonsteroidal anti-inflammatory drugs are used for its treatment. We investigated the effectiveness of difluprednate (Durezol®, recently approved by the US Food and Drug Administration in the treatment of cystoid macular edema, assisted with spectral domain optical coherence tomography (SD-OCT.Case report: A 63-year-old African-American woman presented 6 weeks after uneventful cataract surgery in her left eye with decreased vision and associated distortion of the central visual field. Fluorescein angiogram and SD-OCT confirmed pseudophakic cystoid macular edema. Difluprednate was topically administered twice daily and monitored with serial imaging. Resolution was noted after 1 month of topical therapy, with improvement in visual acuity and resolution of distortion.Conclusion: Difluprednate is an effective treatment for patients with severe pseudophakic cystoid macular edema. SD-OCT allows the physician to monitor resolution of the macular edema easily.Keywords: cystoid macular edema, difluprednate, spectral domain optical coherence tomography, pseudophakic

  7. Optical coherence tomography studies provides new insights into diagnosis and prognosis of infantile nystagmus: a review.

    Science.gov (United States)

    Thomas, Mervyn G; Gottlob, Irene

    2012-12-01

    Infantile nystagmus is commonly associated with afferent abnormalities that can be detected using a range of investigative modalities. Optical coherence tomography allows high-resolution in vivo imaging of the retina. Recent studies have shown characteristic foveal abnormalities in patients with albinism, PAX6 mutations, and isolated foveal hypoplasia. Arrested development of the fovea leads to foveal hypoplasia, which causes reduction in visual acuity. Previous studies have shown correlations between visual acuity and the degree of foveal hypoplasia. Furthermore, in achromatopsia a characteristic lesion has been described that is associated with cone photoreceptor degeneration. Patients with achromatopsia also have foveal hypoplasia, however with atypical features. The signs of photoreceptor degeneration were progressive, which suggests that gene therapy is likely to be most beneficial if given within the first few years of life. With the advent of high speed and ultrahigh resolution optical coherence tomography it is now possible to document reliably the stages of foveal development and cone photoreceptor degeneration. This will aid clinicians in diagnosis and predicting prognosis in patients with infantile nystagmus.

  8. Optical coherence tomography assessment and quantification of intracoronary thrombus: Status and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Italo, E-mail: italo.porto@gmail.com [Interventional Cardiology Unit, San Donato Hospital, Arezzo (Italy); Mattesini, Alessio; Valente, Serafina [Interventional Cardiology Unit, Careggi Hospital, Florence (Italy); Prati, Francesco [Interventional Cardiology San Giovanni Hospital, Rome (Italy); CLI foundation (Italy); Crea, Filippo [Department of Cardiovascular Sciences, Catholic University of the Sacred Heart, Rome (Italy); Bolognese, Leonardo [Interventional Cardiology Unit, San Donato Hospital, Arezzo (Italy)

    2015-04-15

    Coronary angiography is the “golden standard” imaging technique in interventional cardiology and it is still widely used to guide interventions. A major drawback of this technique, however, is that it is inaccurate in the evaluation and quantification of intracoronary thrombus burden, a critical prognosticator and predictor of intraprocedural complications in acute coronary syndromes. The introduction of optical coherence tomography (OCT) holds the promise of overcoming this important limitation, as near-infrared light is uniquely sensitive to hemoglobin, the pigment of red blood cells trapped in the thrombus. This narrative review will focus on the use of OCT for the assessment, evaluation and quantification of intracoronary thrombosis. - Highlights: • Thrombotic burden in acute coronary syndromes Is not adequately evaluated by standard coronary angiography, whereas Optical Coherence Tomography is exquisitely sensitive to the hemoglobin contained in red blood cells and can be used to precisely quantify thrombus. • Both research and clinical applications have been developed using the OCT-based evaluation of thrombus. In particular, whereas precise quantification scores are useful for comparing antithrombotic therapies in randomized trials, both pharmacological and mechanical, the most important practical applications for OCT-based assessment of thrombus are the individuation of culprit lesions in the context of diffuse atheromata in acute coronary syndromes, and the so-called “delayed stenting” strategies. • Improvements in 3D rendering techniques are on the verge of revolutionizing OCT-based thrombus assessment, allowing extremely precise quantification of the thrombotic burden.

  9. Blood flow changes after unilateral carotid artery ligation monitored by optical coherence tomography

    Science.gov (United States)

    Ma, Yushu; Liang, Chengbo; Suo, Yanyan; Zhao, Yuqian; Wang, Yi; Xu, Tao; Wang, Ruikang; Ma, Zhenhe

    2016-03-01

    Unilateral carotid artery ligation which could induce adaptive improvement is a classic model that has been widely used to study pathology of ischemic disease. In those studies, blood flow is an important parameter to characterize the ischemia. Optical coherence tomography (OCT) is a powerful imaging modality which can provide depth resolved images in biological tissue with high spatial and temporal resolution. SPF rats was anesthetized with isoflurane and divided into two groups. In first group, bilateral carotid artery was surgically exposed, and then left carotid artery was ligated. Blood flow changes of the contralateral carotid artery was monitored using high speed spectral domain optical coherence tomography, including the absolute flow velocity and the flow volume. In the other group, skull window was opened at the ipsilateral cerebral cortex of ligation and blood supply of small artery was measured before and after the ligation. The measured results demonstrate the blood supply compensation process after unilateral carotid artery ligation. With the superiority of high resolution, OCT is an effective technology in monitoring results of carotid artery after ligation.

  10. Optical coherence tomography diagnostics for onco–urology. Review of clinical perspectives

    Directory of Open Access Journals (Sweden)

    Sergiy Kharchenko

    2013-01-01

    Full Text Available Introduction. Optical coherence tomography (OCT is being investigated widely for use in urologic pathology. The current imaging of urogenital cancers cannot be perfect, thus, routine methods demands new updates or inventions of alternative radiological scope. OCT presents so–called “live” optical biopsy. The authors aim to review this modality for uro–oncological purposes.Matherial and methods. A series of 37 publications between 1989 and 2012 was selected and cited from GoogleScholar and PubMED/MEDLINE. The urogenital tract (bladder, ureter, scrotum organs and prostate was imaged by OCT.Results. The overall OCT sensitivity, specificity, accuracy, negative and positive predictive values ranged a lot on example of the urinary bladder’s tumors screening. The data were 75–100%, 65–97.9%, 92%, 75%, 100%, respectively. Notwithstanding, a diagnostic importance of OCT may be comparable with urine cytology, cystoscopy, computerized tomography and magnetic resonance imaging.Conclusions. OCT demonstrated its imaging potential, while till the present OCT plays role of an additional imaging. Future progress of OCT involvement in experimental and clinical once–urological diagnostics is needed under high evidence control.

  11. Simulation of a fast diffuse optical tomography system based on radiative transfer equation

    Science.gov (United States)

    Motevalli, S. M.; Payani, A.

    2016-12-01

    Studies show that near-infrared (NIR) light (light with wavelength between 700nm and 1300nm) undergoes two interactions, absorption and scattering, when it penetrates a tissue. Since scattering is the predominant interaction, the calculation of light distribution in the tissue and the image reconstruction of absorption and scattering coefficients are very complicated. Some analytical and numerical methods, such as radiative transport equation and Monte Carlo method, have been used for the simulation of light penetration in tissue. Recently, some investigators in the world have tried to develop a diffuse optical tomography system. In these systems, NIR light penetrates the tissue and passes through the tissue. Then, light exiting the tissue is measured by NIR detectors placed around the tissue. These data are collected from all the detectors and transferred to the computational parts (including hardware and software), which make a cross-sectional image of the tissue after performing some computational processes. In this paper, the results of the simulation of an optical diffuse tomography system are presented. This simulation involves two stages: a) Simulation of the forward problem (or light penetration in the tissue), which is performed by solving the diffusion approximation equation in the stationary state using FEM. b) Simulation of the inverse problem (or image reconstruction), which is performed by the optimization algorithm called Broyden quasi-Newton. This method of image reconstruction is faster compared to the other Newton-based optimization algorithms, such as the Levenberg-Marquardt one.

  12. Ultra-high resolution optical coherence tomography analysis of bull's eye maculopathy in chloroquine users

    Directory of Open Access Journals (Sweden)

    Celso Morita

    2014-06-01

    Full Text Available Purpose: Register and compare anatomical changes, structural and quantitative found in optical coherence tomography Stratus and Topcon 3D in chronic users of chloroquine. Methods: Five patients were diagnosed with toxic "bull's eye" maculopathy was submitted to macular optical coherence tomography examination (Stratus and Topcon 3D. Results: Both tools demonstrated an increase reflectivity of choriocapillaris unit just foveal retinal pigment epithelium atrophy. However, Topcon 3D provided to all patients better description of the line corresponding to the transition between inner and outer segments of photoreceptors. Using the possibility of assembling threedimensional images and subtraction selective retinal layers, we found a lesion with a target that reflects the greater thickness of retinal pigment epithelium in central and parafoveal region that is matched to preserve macular photoreceptors. Conclusion: it was observed better resolution and faster image capture by Topcon 3D than Stratus OCT, that provided more detailed analysis of the line corresponding to transition between outer and inner segment of photoreceptors in macular region. With Topcon 3D, it was possible to evaluate soundly the thickness of retinal pigment epithelium in central and parafoveal region that caused an increase reflectivity of choriocapillaris creating a image with a target unpublished before.

  13. Three-dimensional imaging of artificial fingerprint by optical coherence tomography

    Science.gov (United States)

    Larin, Kirill V.; Cheng, Yezeng

    2008-03-01

    Fingerprint recognition is one of the popular used methods of biometrics. However, due to the surface topography limitation, fingerprint recognition scanners are easily been spoofed, e.g. using artificial fingerprint dummies. Thus, biometric fingerprint identification devices need to be more accurate and secure to deal with different fraudulent methods including dummy fingerprints. Previously, we demonstrated that Optical Coherence Tomography (OCT) images revealed the presence of the artificial fingerprints (made from different household materials, such as cement and liquid silicone rubber) at all times, while the artificial fingerprints easily spoofed the commercial fingerprint reader. Also we demonstrated that an analysis of the autocorrelation of the OCT images could be used in automatic recognition systems. Here, we exploited the three-dimensional (3D) imaging of the artificial fingerprint by OCT to generate vivid 3D image for both the artificial fingerprint layer and the real fingerprint layer beneath. With the reconstructed 3D image, it could not only point out whether there exists an artificial material, which is intended to spoof the scanner, above the real finger, but also could provide the hacker's fingerprint. The results of these studies suggested that Optical Coherence Tomography could be a powerful real-time noninvasive method for accurate identification of artificial fingerprints real fingerprints as well.

  14. Argus II retinal prosthesis malrotation and repositioning with intraoperative optical coherence tomography in a posterior staphyloma

    Directory of Open Access Journals (Sweden)

    Seider MI

    2015-11-01

    Full Text Available Michael I Seider, Paul Hahn Duke University Eye Center, Durham, NC, USA Introduction: The Argus II retinal prosthesis may improve visual function in patients with severe vision loss from retinitis pigmentosa. Optimal centration of the electrode array over the macula is important to achieve optimal visual results. Argus tack malrotation is a novel entity that may be encountered during placement, especially in patients with posterior staphyloma.Methods: Retrospective case review.Results: During tacking of the electronics array a clockwise rotation occurred resulting in malposition. We hypothesize this was secondary to undue rotation or posterior pressure applied during tack insertion in conjunction with placement over a previously unrecognized posterior staphyloma. Intraoperative optical coherence tomography, because of the cross-sectional images provided, was helpful in visualizing the distance between the electronics array and the retina, which was difficult to assess using the surgical microscope alone. Repositioning was achieved by adjusting the tack without removal. The patient experienced an improvement in vision as a result of the surgery.Conclusion: Malrotation may occur when tacking the Argus II prosthesis, and the presence of a posterior staphyloma may increase this risk. It is important to differentiate malrotation from tack misplacement – the former may be addressed with array unrotation or partial tack withdrawal and the latter may require tack removal and reinsertion. Also, intraoperative optical coherence tomography may be helpful in characterizing electronics array position during surgery. Keywords: Argus, retinitis pigmentosa, retinal tack

  15. Monitoring neovascularization in aggressive posterior retinopathy of prematurity using optical coherence tomography angiography.

    Science.gov (United States)

    Vinekar, Anand; Chidambara, Lavanya; Jayadev, Chaitra; Sivakumar, Munusamy; Webers, Carroll A B; Shetty, Bhujang

    2016-06-01

    We describe the use of optical coherence tomography angiography (OCTA) in detecting and monitoring regression of the neovascular complex (NVC) in a case of aggressive posterior retinopathy of prematurity (AP-ROP). A premature Asian Indian girl with AP-ROP underwent laser photoablation at 26 days of life. Persistent NVC at the posterior border of the lasered retinal bed was detected clinically. On en face spectral domain optical coherence tomography (SD-OCT) and OCTA, the NVC appeared as an arborizing vascular net in the superficial capillary plexus. The deep capillary plexus and outer retinal layers showed corresponding flow outlines that suggested deeper extensions of the lesion. Supplemental laser treatment of the NVC was performed. Ten days later repeat en face SD-OCT and OCTA of the identical retinal location revealed that the vascular tortuosity and dilatation had reduced and that the flow lesions in the deeper layers were undetectable. Our findings in this case suggest that the NVC in AP-ROP extends beyond the superficial retina.

  16. The influence of glass fibers on elongational viscosity studied by means of optical coherence tomography and X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Aigner, M., E-mail: michael.aigner@jku.at; Köpplmayr, T., E-mail: thomas.koepplmayr@jku.at, E-mail: Christian.lang@jku.at; Lang, C., E-mail: thomas.koepplmayr@jku.at, E-mail: Christian.lang@jku.at; Burzic, I., E-mail: ivana.burzic@jku.at, E-mail: juergen.miethlinger@jku.at; Miethlinger, J., E-mail: ivana.burzic@jku.at, E-mail: juergen.miethlinger@jku.at [Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz (Austria); Salaberger, D., E-mail: dietmar.salaberger@fh-wels.at [University of Applied Sciences Upper Austria (Austria); Buchsbaum, A., E-mail: andreas.buchsbaum@recendt.at; Leitner, M. [Research Center for Non Destructive Testing GmbH (Austria); Heise, B., E-mail: bettina.heise@jku.at [Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, ZONA, Austria and Institute for Knowledge-based Mathematical Systems, Johannes Kepler University Linz (Austria); Schausberger, S. E., E-mail: stefan.schausberger@jku.at; Stifter, D. [Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, ZONA (Austria)

    2014-05-15

    We report on the flow characteristics of glass-fiber-reinforced polymers in elongational rheometry. Unlike polymers with geometrically isotropic fillers, glass-fiber-reinforced polymers exhibit flow behavior and rheology that depend heavily on the orientation, the length distribution and the content of the fibers. One of the primary objectives of this study was to determine the effect of fiber orientation, concentration and distribution on the entrance pressure drop by means of optical coherence tomography (OCT), full-field optical coherence microscopy (FF-OCM), and X-ray computed tomography (X-CT). Both pressure drop and melt flow were analyzed using a special elongation die (Thermo Scientific X-Die [3]) for inline measurements. Samples with a variety of fiber volume fractions, fiber lengths and processing temperatures were measured.

  17. Imaging internal flows in a drying sessile polymer dispersion drop using Spectral Radar Optical Coherence Tomography (SR-OCT).

    Science.gov (United States)

    Manukyan, Selin; Sauer, Hans M; Roisman, Ilia V; Baldwin, Kyle A; Fairhurst, David J; Liang, Haida; Venzmer, Joachim; Tropea, Cameron

    2013-04-01

    In this work, we present the visualization of the internal flows in a drying sessile polymer dispersion drop on hydrophilic and hydrophobic surfaces with Spectral Radar Optical Coherence Tomography (SR-OCT). We have found that surface features such as the initial contact angle and pinning of the contact line, play a crucial role on the flow direction and final shape of the dried drop. Moreover, imaging through selection of vertical slices using optical coherence tomography offers a feasible alternative compared to imaging through selection of narrow horizontal slices using confocal microscopy for turbid, barely transparent fluids.

  18. Optical Coherence Tomography Parameters in Morbidly Obese Patients Who Underwent Laparoscopic Sleeve Gastrectomy

    Directory of Open Access Journals (Sweden)

    Berna Dogan

    2016-01-01

    Full Text Available Purpose. To investigate changes in optical coherence tomography parameters in morbidly obese patients who had undergone laparoscopic sleeve gastrectomy (LSG. Methods. A total of 41 eyes of 41 morbidly obese patients (BMI ≥ 40 who had undergone LSG were included in study. The topographic optic disc parameters, central macular thickness (CMT, total macular volume (TMV, and retinal ganglion cell layer (RGCL were measured by spectral-domain optical coherence tomography (SD-OCT. Subfoveal choroidal thickness (SFCT was measured by enhanced deep imaging-optical coherence tomography (EDI-OCT. Results. The mean CMT was 237.4±24.5 μm, 239.3±24.1 μm, and 240.4±24.5 μm preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. The mean TMV was 9.88±0.52 mm3, 9.96±0.56 mm3, and 9.99±0.56 mm3 preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. The mean RGCL was 81.2±6.5 μm, 82.7±6.6 μm, and 82.9±6.5 μm preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. The mean SFCT was 309.8±71.8 μm, 331.0±81.4 μm, and 352.7±81.4 μm preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. No statistically significant differences were found between the preoperative values and 3- and 6-month postoperative values in rim area (p=0.34, disc area (p=0.64, vertical cup/disc ratio (p=0.39, cup volume (p=0.08, or retinal nerve fiber layer (p=0.90. Conclusions. Morbidly obese patients who undergo LSG experience a statistically significant increase in CMT, TMV, SFCT, and RGCL at 3 months and 6 months after surgery.

  19. Time-frequency analysis in optical coherence tomography for technical objects examination

    Science.gov (United States)

    StrÄ kowski, Marcin R.; Kraszewski, Maciej; Trojanowski, Michał; Pluciński, Jerzy

    2014-05-01

    Optical coherence tomography (OCT) is one of the most advanced optical measurement techniques for complex structure visualization. The advantages of OCT have been used for surface and subsurface defect detection in composite materials, polymers, ceramics, non-metallic protective coatings, and many more. Our research activity has been focused on timefrequency spectroscopic analysis in OCT. It is based on time resolved spectral analysis of the backscattered optical signal delivered by the OCT. The time-frequency method gives spectral characteristic of optical radiation backscattered or backreflected from the particular points inside the tested device. This provides more information about the sample, which are useful for further analysis. Nowadays, the applications of spectroscopic analysis for composite layers characterization or tissue recognition have been reported. During our studies we have found new applications of spectroscopic analysis. We have used this method for thickness estimation of thin films, which are under the resolution of OCT. Also, we have combined the spectroscopic analysis with polarization sensitive OCT (PS-OCT). This approach enables to obtain a multiorder retardation value directly and may become a breakthrough in PS-OCT measurements of highly birefringent media. In this work, we present the time-frequency spectroscopic algorithms and their applications for OCT. Also, the theoretical simulations and measurement validation of this method are shown.

  20. Gradient-based iterative image reconstruction scheme for time-resolved optical tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, A.H.; Klose, A.D. [State Univ. of New York, Brooklyn, NY (United States). Dept. of Pathology; Hanson, K.M. [Los Alamos National Lab., NM (United States)

    1999-03-01

    Currently available tomographic image reconstruction schemes for optical tomography (OT) are mostly based on the limiting assumptions of small perturbations and a priori knowledge of the optical properties of a reference medium. Furthermore, these algorithms usually require the inversion of large, full, ill-conditioned Jacobian matrices. In this work a gradient-based iterative image reconstruction (GIIR) method is presented that promises to overcome current limitations. The code consists of three major parts: (1) A finite-difference, time-resolved, diffusion forward model is used to predict detector readings based on the spatial distribution of optical properties; (2) An objective function that describes the difference between predicted and measured data; (3) An updating method that uses the gradient of the objective function in a line minimization scheme to provide subsequent guesses of the spatial distribution of the optical properties for the forward model. The reconstruction of these properties is completed, once a minimum of this objective function is found. After a presentation of the mathematical background, two- and three-dimensional reconstruction of simple heterogeneous media as well as the clinically relevant example of ventricular bleeding in the brain are discussed. Numerical studies suggest that intraventricular hemorrhages can be detected using the GIIR technique, even in the presence of a heterogeneous background.

  1. Spectral domain optical coherence tomography with extended depth-of-focus by aperture synthesis

    Science.gov (United States)

    Bo, En; Liu, Linbo

    2016-10-01

    We developed a spectral domain optical coherence tomography (SD-OCT) with an extended depth-of-focus (DOF) by synthetizing aperture. For a designated Gaussian-shape light source, the lateral resolution was determined by the numerical aperture (NA) of the objective lens and can be approximately maintained over the confocal parameter, which was defined as twice the Rayleigh range. However, the DOF was proportional to the square of the lateral resolution. Consequently, a trade-off existed between the DOF and lateral resolution, and researchers had to weigh and judge which was more important for their research reasonably. In this study, three distinct optical apertures were obtained by imbedding a circular phase spacer in the sample arm. Due to the optical path difference between three distinct apertures caused by the phase spacer, three images were aligned with equal spacing along z-axis vertically. By correcting the optical path difference (OPD) and defocus-induced wavefront curvature, three images with distinct depths were coherently summed together. This system digitally refocused the sample tissue and obtained a brand new image with higher lateral resolution over the confocal parameter when imaging the polystyrene calibration beads.

  2. Doppler Fourier Domain Optical Coherence Tomography for Label-Free Tissue Angiography

    Science.gov (United States)

    Leitgeb, Rainer A.; Szkulmowski, Maciej; Blatter, Cedric; Wojtkowski, Maciej

    Information about tissue perfusion and the vascular structure is certainly most important for assessment of tissue state or personal health and the diagnosis of any pathological conditions. It is therefore of key medical interest to have tools available for both quantitative blood flow assessment as well as qualitative vascular imaging. The strength of optical techniques is the unprecedented level of detail even for small capillary structures or microaneurysms and the possibility to combine different techniques for additional tissue spectroscopy giving insight into tissue metabolism. There is an immediate diagnostic and pharmacological demand for high-resolution, label-free, tissue angiography and flow assessment that in addition allow for precise depth gating of flow information. The most promising candidate is Doppler optical coherence tomography (DOCT) being noncontact, label free, and without employing hazardous radiation. DOCT provides fully quantitative volumetric information about blood flow together with the vascular and structural anatomy. Besides flow quantification, analysis of OCT signal fluctuations allows to contrast moving scatterers in tissue such as red blood cells from static tissue. This allows for non-invasive optical angiography and yields high resolution even for smallest capillaries. Because of the huge potential of DOCT and lable-free optical angiography for diagnosis, the last years saw a rapid increase of publications in this field with many different approaches. The present chapter gives an overview over existing Doppler OCT approaches and angiography techniques. It furthermore discusses limitations and noise issues, and gives examples for angiography in the eye and the skin.

  3. Monitoring of interaction of low-frequency electric field with biological tissues upon optical clearing with optical coherence tomography

    Science.gov (United States)

    Peña, Adrián F.; Doronin, Alexander; Tuchin, Valery V.; Meglinski, Igor

    2014-08-01

    The influence of a low-frequency electric field applied to soft biological tissues ex vivo at normal conditions and upon the topical application of optical clearing agents has been studied by optical coherence tomography (OCT). The electro-kinetic response of tissues has been observed and quantitatively evaluated by the double correlation OCT approach, utilizing consistent application of an adaptive Wiener filtering and Fourier domain correlation algorithm. The results show that fluctuations, induced by the electric field within the biological tissues are exponentially increased in time. We demonstrate that in comparison to impedance measurements and the mapping of the temperature profile at the surface of the tissue samples, the double correlation OCT approach is much more sensitive to the changes associated with the tissues' electro-kinetic response. We also found that topical application of the optical clearing agent reduces the tissues' electro-kinetic response and is cooling the tissue, thus reducing the temperature induced by the electric current by a few degrees. We anticipate that dcOCT approach can find a new application in bioelectrical impedance analysis and monitoring of the electric properties of biological tissues, including the resistivity of high water content tissues and its variations.

  4. Morphological and functional changes in spectral domain optical coherence tomography and microperimetry in macular microhole variants: Spectral domain optical coherence tomography and microperimetry correlation

    Directory of Open Access Journals (Sweden)

    Laxmi Gella

    2012-01-01

    Full Text Available Purpose: To evaluate the relationship between the morphology and retinal function of macular microhole (MMH variants. Materials and Methods: We evaluated 12 eyes of 11 patients with defects in the IS/OS junction of photoreceptor layer with SD-OCT. All patients underwent comprehensive ophthalmic examination including spectral domain optical coherence tomography (SD-OCT and microperimetry. Results: The mean logMAR visual acuity in the affected eye was 0.15 ± 0.17 (range 0.00-0.5. Mean horizontal diameter of the MMH was 163 ± 99 μm; the mean retinal sensitivity in the area corresponding to the MMH was 13.79 ± 4.6 dB. Negative correlation was found between the MMH diameter and the retinal sensitivity (r = -0.65, p0 = 0.02. Three morphological patterns of MMH variants were recognized on SD-OCT, which did not differ in retinal sensitivities. Conclusion: We described and classified the MMH variants and made an assessment on the physiological functions using microperimeter.

  5. High-resolution imaging of biological tissue with full-field optical coherence tomography

    Science.gov (United States)

    Zhu, Yue; Gao, Wanrong

    2015-03-01

    A new full-field optical coherence tomography system with high-resolution has been developed for imaging of cells and tissues. Compared with other FF-OCT (Full-field optical coherence tomography, FF-OCT) systems illuminated with optical fiber bundle, the improved Köhler illumination arrangement with a halogen lamp was used in the proposed FF-OCT system. High numerical aperture microscopic objectives were used for imaging and a piezoelectric ceramic transducer (PZT) was used for phase-shifting. En-face tomographic images can be obtained by applying the five-step phase-shifting algorithm to a series of interferometric images which are recorded by a smart camera. Three-dimensional images can be generated from these tomographic images. Imaging of the chip of Intel Pentium 4 processor demonstrated the ultrahigh resolution of the system (lateral resolution is 0.8μm ), which approaches the theoretical resolution 0.7 μm× 0.5 μm (lateral × axial). En-face images of cells of onion show an excellent performance of the system in generating en-face images of biological tissues. Then, unstained pig stomach was imaged as a tissue and gastric pits could be easily recognized using FF-OCT system. Our study provides evidence for the potential ability of FFOCT in identifying gastric pits from pig stomach tissue. Finally, label-free and unstained ex vivo human liver tissues from both normal and tumor were imaged with this FFOCT system. The results show that the setup has the potential for medical diagnosis applications such liver cancer diagnosis.

  6. Offline fusion of co-registered intravascular ultrasound and frequency domain optical coherence tomography images for the analysis of human atherosclerotic plaques

    DEFF Research Database (Denmark)

    Räber, Lorenz; Heo, Jung Ho; Radu, Maria D

    2012-01-01

    To demonstrate the feasibility and potential usefulness of an offline fusion of matched optical coherence tomography (OCT) and intravascular ultrasound (IVUS)/virtual histology (IVUS-VH) images.......To demonstrate the feasibility and potential usefulness of an offline fusion of matched optical coherence tomography (OCT) and intravascular ultrasound (IVUS)/virtual histology (IVUS-VH) images....

  7. Multimodal photoacoustic and optical coherence tomography scanner using an all optical detection scheme for 3D morphological skin imaging.

    Science.gov (United States)

    Zhang, Edward Z; Povazay, Boris; Laufer, Jan; Alex, Aneesh; Hofer, Bernd; Pedley, Barbara; Glittenberg, Carl; Treeby, Bradley; Cox, Ben; Beard, Paul; Drexler, Wolfgang

    2011-08-01

    A noninvasive, multimodal photoacoustic and optical coherence tomography (PAT/OCT) scanner for three-dimensional in vivo (3D) skin imaging is described. The system employs an integrated, all optical detection scheme for both modalities in backward mode utilizing a shared 2D optical scanner with a field-of-view of ~13 × 13 mm(2). The photoacoustic waves were detected using a Fabry Perot polymer film ultrasound sensor placed on the surface of the skin. The sensor is transparent in the spectral range 590-1200 nm. This permits the photoacoustic excitation beam (670-680 nm) and the OCT probe beam (1050 nm) to be transmitted through the sensor head and into the underlying tissue thus providing a backward mode imaging configuration. The respective OCT and PAT axial resolutions were 8 and 20 µm and the lateral resolutions were 18 and 50-100 µm. The system provides greater penetration depth than previous combined PA/OCT devices due to the longer wavelength of the OCT beam (1050 nm rather than 829-870 nm) and by operating in the tomographic rather than the optical resolution mode of photoacoustic imaging. Three-dimensional in vivo images of the vasculature and the surrounding tissue micro-morphology in murine and human skin were acquired. These studies demonstrated the complementary contrast and tissue information provided by each modality for high-resolution 3D imaging of vascular structures to depths of up to 5 mm. Potential applications include characterizing skin conditions such as tumors, vascular lesions, soft tissue damage such as burns and wounds, inflammatory conditions such as dermatitis and other superficial tissue abnormalities.

  8. Diagnostic ability of Humphrey perimetry, Octopus perimetry, and optical coherence tomography for glaucomatous optic neuropathy.

    Science.gov (United States)

    Monsalve, B; Ferreras, A; Calvo, P; Urcola, J A; Figus, M; Monsalve, J; Frezzotti, P

    2016-11-11

    PurposeTo evaluate and compare the diagnostic accuracy of the Humphrey Field Analyzer (HFA), Octopus perimetry, and Cirrus OCT for glaucomatous optic neuropathy.MethodsEighty-eight healthy individuals and 150 open-angle glaucoma patients were consecutive and prospectively selected. Eligibility criteria for the glaucoma group were intraocular pressure ≥21 mm Hg and glaucomatous optic nerve head morphology. All subjects underwent a reliable standard automated perimetry with the HFA and Octopus perimeter, and were imaged with the Cirrus OCT. Receiver-operating characteristic (ROC) curves were plotted for the threshold values and main indices of the HFA and Octopus, the peripapillary retinal nerve fiber layer thicknesses, and the optic nerve head parameters. Sensitivities at 85 and 95% fixed-specificities were also calculated. The best areas under the ROC curves (AUCs) were compared using the DeLong method.ResultsIn the glaucoma group, mean deviation (MD) was -5.42±4.6 dB for HFA and 3.90±3.6 dB for Octopus. The MD of the HFA (0.966; P<0.001), mean sensitivity of the Octopus (0.941; P<0.001), and average cup-to-disc (C/D) ratio measured by the Cirrus OCT (0.958; P<0.001) had the largest AUCs for each test studied. There were no significant differences among them. Sensitivities at 95% fixed-specificity were 82% for pattern standard deviation of the HFA, 81.3% for average C/D ratio of OCT, and 80% for the MD of the Octopus.ConclusionsHFA, Octopus, and Cirrus OCT demonstrated similar diagnostic accuracies for glaucomatous optic neuropathy. Visual field and OCT provide supplementary information and thus these tests are not interchangeable.Eye advance online publication, 11 November 2016; doi:10.1038/eye.2016.251.

  9. Apices of maxillary premolars observed by swept source optical coherence tomography

    Science.gov (United States)

    Ebihara, Arata; Iino, Yoshiko; Yoshioka, Toshihiko; Hanada, Takahiro; Sunakawa, Mitsuhiro; Sumi, Yasunori; Suda, Hideaki

    2015-02-01

    Apicoectomy is performed for the management of apical periodontitis when orthograde root canal treatment is not possible or is ineffective. Prior to the surgery, cone beam computed tomography (CBCT) examination is often performed to evaluate the lesion and the adjacent tissues. During the surgical procedure, the root apex is resected and the resected surface is usually observed under dental operating microscope (DOM). However, it is difficult to evaluate the details and the subsurface structure of the root using CBCT and DOM. A new diagnostic system, swept source optical coherence tomography (SS-OCT), has been developed to observe the subsurface anatomical structure. The aim of this study was to observe resected apical root canals of human maxillary premolars using SS-OCT and compare the findings with those observed using CBCT and DOM. Six extracted human maxillary premolars were used. After microfocus computed tomography (Micro CT; for gold standard) and CBCT scanning of the root, 1 mm of the apex was cut perpendicular to the long axis of the tooth. Each resected surface was treated with EDTA, irrigated with saline solution, and stained with methylene blue dye. The resected surface was observed with DOM and SS-OCT. This sequence was repeated three times. The number of root canals was counted and statistically evaluated. There was no significant difference in the accuracy of detecting root canals among CBCT, DOM and SS-OCT (p > 0.05, Wilcoxon test). Because SS-OCT can be used in real time during surgery, it would be a useful tool for observing resected apical root canals.

  10. Stray light in cone beam optical computed tomography: II. Reduction using a convergent light source

    Science.gov (United States)

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2016-04-01

    Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1  ±  2)% between mean values over a wide range from 0.036 to 0.43 cm-1. For the finger phantom, agreement is found with a maximum deviation of (4  ±  2)% between mean values over a range of 0.1-0.47 cm-1. With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

  11. Small field dose delivery evaluations using cone beam optical computed tomography-based polymer gel dosimetry

    Directory of Open Access Journals (Sweden)

    Timothy Olding

    2011-01-01

    Full Text Available This paper explores the combination of cone beam optical computed tomography with an N-isopropylacrylamide (NIPAM-based polymer gel dosimeter for three-dimensional dose imaging of small field deliveries. Initial investigations indicate that cone beam optical imaging of polymer gels is complicated by scattered stray light perturbation. This can lead to significant dosimetry failures in comparison to dose readout by magnetic resonance imaging (MRI. For example, only 60% of the voxels from an optical CT dose readout of a 1 l dosimeter passed a two-dimensional Low′s gamma test (at a 3%, 3 mm criteria, relative to a treatment plan for a well-characterized pencil beam delivery. When the same dosimeter was probed by MRI, a 93% pass rate was observed. The optical dose measurement was improved after modifications to the dosimeter preparation, matching its performance with the imaging capabilities of the scanner. With the new dosimeter preparation, 99.7% of the optical CT voxels passed a Low′s gamma test at the 3%, 3 mm criteria and 92.7% at a 2%, 2 mm criteria. The fitted interjar dose responses of a small sample set of modified dosimeters prepared (a from the same gel batch and (b from different gel batches prepared on the same day were found to be in agreement to within 3.6% and 3.8%, respectively, over the full dose range. Without drawing any statistical conclusions, this experiment gives a preliminary indication that intrabatch or interbatch NIPAM dosimeters prepared on the same day should be suitable for dose sensitivity calibration.

  12. Assessment of the optic nerve head parameters using Heidelberg retinal tomography III in preterm children.

    Directory of Open Access Journals (Sweden)

    Salem Alshaarawi

    Full Text Available BACKGROUND: Variations in optic nerve head morphology and abnormal retinal vascular pattern have been described in preterm children using digital image analysis of fundus photograph, optical coherence tomograph and serial funduscopy. We aimed to compare the optic nerve head parameters in preterm and term Malay children using Heidelberg Retinal Tomograph III. DESIGN: A cross sectional study. METHODOLOGY/PRINCIPAL FINDINGS: Thirty-two preterm Malay children who were born at up to 32 weeks postconception, and 32 term Malay children aged 8-16 years old were recruited into this cross sectional study, which was conducted in the Hospital Universiti Sains Malaysia, Malaysia from January to December 2011. Their optic nerves were scanned and analyzed using a Heidelberg Retinal Tomography (HRT III (Heidelberg Engineering, Germany. Preterm children showed an increased rim volume (SD (0.56 (0.26 vs 0.44 (0.18 mm(3, respectively, smaller cup shape (SD (0.18 (0.07 vs 0.25 (0.06 mm, respectively, increased height variation contour (SD (0.44 (0.14 vs 0.35 (0.08 mm, respectively, and increased cup depth (SD (0.24 (0.11 vs 0.17 (0.05 mm(3, respectively when compared to their normal peers (p0.05 in our study. CONCLUSIONS/SIGNIFICANCE: Preterm children exhibit different characteristics of optic nerve head parameters with HRT III analysis. Increased cup depth in preterm children suggests a need for close observation and monitoring. It may raise suspicion of pediatric glaucoma when proper documentation of intraocular pressure and clinical funduscopy are unsuccessful in uncooperative children.

  13. Stray light in cone beam optical computed tomography: II. Reduction using a convergent light source.

    Science.gov (United States)

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2016-04-07

    Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1  ±  2)% between mean values over a wide range from 0.036 to 0.43 cm(-1). For the finger phantom, agreement is found with a maximum deviation of (4  ±  2)% between mean values over a range of 0.1-0.47 cm(-1). With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

  14. Depth-encoded synthetic aperture optical coherence tomography of biological tissues with extended focal depth.

    Science.gov (United States)

    Mo, Jianhua; de Groot, Mattijs; de Boer, Johannes F

    2015-02-23

    Optical coherence tomography (OCT) has proven to be able to provide three-dimensional (3D) volumetric images of scattering biological tissues for in vivo medical diagnostics. Unlike conventional optical microscopy, its depth-resolving ability (axial resolution) is exclusively determined by the laser source and therefore invariant over the full imaging depth. In contrast, its transverse resolution is determined by the objective's numerical aperture and the wavelength which is only approximately maintained over twice the Rayleigh range. However, the prevailing laser sources for OCT allow image depths of more than 5 mm which is considerably longer than the Rayleigh range. This limits high transverse resolution imaging with OCT. Previously, we reported a novel method to extend the depth-of-focus (DOF) of OCT imaging in Mo et al.Opt. Express 21, 10048 (2013)]. The approach is to create three different optical apertures via pupil segmentation with an annular phase plate. These three optical apertures produce three OCT images from the same sample, which are encoded to different depth positions in a single OCT B-scan. This allows for correcting the defocus-induced curvature of wave front in the pupil so as to improve the focus. As a consequence, the three images originating from those three optical apertures can be used to reconstruct a new image with an extended DOF. In this study, we successfully applied this method for the first time to both an artificial phantom and biological tissues over a four times larger depth range. The results demonstrate a significant DOF improvement, paving the way for 3D high resolution OCT imaging beyond the conventional Rayleigh range.

  15. Optical coherence tomography findings in Huntington's disease: a potential biomarker of disease progression.

    Science.gov (United States)

    Kersten, Hannah M; Danesh-Meyer, Helen V; Kilfoyle, Dean H; Roxburgh, Richard H

    2015-11-01

    Previous reports of ocular abnormalities in Huntington's disease (HD) have detailed eye movement disorders. The objective of this case-control study was to investigate optic nerve and macular morphology in HD using optical coherence tomography (OCT). A total of 26 HD patients and 29 controls underwent a thorough ophthalmic examination including spectral domain OCT scans of the macula and peripapillary retinal nerve fibre layer (RNFL). Genetic testing results, disease duration, HD disease burden scores and Unified HD Rating Scale motor scores were acquired for HD patients. Temporal RNFL thickness was significantly reduced in the HD group (62.3 vs. 69.8 μm, p = 0.005), and there was a significant negative correlation between temporal RNFL thickness and disease duration (R (2) = -0.51, p = 0.04). Average peripapillary RNFL thickness was not significantly different between the HD and control groups. There was a significant negative correlation between macular volume and disease duration (R (2) = -0.71, p = 0.002), and motor scores (R (2) = -0.56, p = 0.01). Colour vision was significantly poorer in the HD group. Temporal RNFL is preferentially thinned in HD patients, possibly implicating mitochondrial dysfunction as the temporal RNFL is reduced in the patients with some mitochondrial disorders, including Leber's hereditary optic neuropathy. The correlation between the decrease in macular volume and temporal RNFL, and increasing disease severity suggests that OCT may be a useful biomarker for disease progression in HD. Larger, longitudinal studies are required.

  16. Optimal Analysis Method for Dynamic Contrast-Enhanced Diffuse Optical Tomography

    Directory of Open Access Journals (Sweden)

    Michael Ghijsen

    2011-01-01

    Full Text Available Diffuse Optical Tomography (DOT is an optical imaging modality that has various clinical applications. However, the spatial resolution and quantitative accuracy of DOT is poor due to strong photon scatting in biological tissue. Structural a priori information from another high spatial resolution imaging modality such as Magnetic Resonance Imaging (MRI has been demonstrated to significantly improve DOT accuracy. In addition, a contrast agent can be used to obtain differential absorption images of the lesion by using dynamic contrast enhanced DOT (DCE-DOT. This produces a relative absorption map that consists of subtracting a reconstructed baseline image from reconstructed images in which optical contrast is included. In this study, we investigated and compared different reconstruction methods and analysis approaches for regular endogenous DOT and DCE-DOT with and without MR anatomical a priori information for arbitrarily-shaped objects. Our phantom and animal studies have shown that superior image quality and higher accuracy can be achieved using DCE-DOT together with MR structural a priori information. Hence, implementation of a combined MRI-DOT system to image ICG enhancement can potentially be a promising tool for breast cancer imaging.

  17. Photodynamic therapy induces epidermal thickening in hairless mice skin: an optical coherence tomography assessment

    Science.gov (United States)

    Jorge, Ana Elisa S.; Campos, Carolina P.; Freitas, Anderson Z.; Bagnato, Vanderlei S.

    2014-03-01

    Photodynamic therapy (PDT) promotes skin improvement according to many practitioners, however the immediately in vivo assessment of its response remains clinically inaccessible. As a non-invasive modality, optical coherence tomography (OCT) has been shown a feasible optical diagnostic technique that provides images in real time, avoiding tissue biopsies. For this reason, our investigation focused on evaluates the PDT effect on a rodent model by means of OCT. Therefore, a normal hairless mouse skin has undergone a single-session PDT, which was performed with topical 5- aminolevulinic acid (ALA) cream using a red (630 nm) light emitting diode (LED) which reached the light dose of 75 J/cm2. As the optical imaging tool, an OCT (930 nm) with axial resolution of 6.0 microns in air was used, generating images with contact to the mouse skin before, immediately after, 24 hours, and 2 weeks after the correspondent procedure. Our result demonstrates that, within 24 hours after ALA-PDT, the mouse skin from the PDT group has shown epidermal thickness (ET), which has substantially increased after 2 weeks from the treatment day. Moreover, the skin surface has become evener after ALA-PDT. Concluding, this investigation demonstrates that the OCT is a feasible and reliable technique that allows real-time cross-sectional imaging of skin, which can quantify an outcome and predict whether the PDT reaches its goal.

  18. High-resolution multiphoton optical tomography of tissues: an in vitro and in vivo study

    Science.gov (United States)

    Riemann, Iris; Schenke-Layland, Katja; Ehlers, Alexander; Dimitrow, Enrico; Kaatz, Martin; Elsner, Peter; Martin, Sven; König, Karsten

    2006-03-01

    Multiphoton optical tomography based on NIR (near-infrared) femtosecond laser pulses provides non-invasive optical sectioning of skin with high spatial intracellular resolution and high tissue penetration. The imaging system DermaInspect was used to perform this technology in clinical studies in vivo on patients with suspicious melanoma. Pigmented cell clusters based on non-linear luminescence were clearly distinguished from non-pigmented cells in the epidermis using the autofluorescence of endogenous fluorophores like NAD(P)H, flavins, keratin, elastin, collagen and melanin. Some of the investigated tissues showed differences in the structure of the epidermal layers and the presence of dendritic cells compared to normal skin. Multiphoton laser microscopy was used to visualize extracellular matrix (ECM) structures of native and tissueengineered heart valves. The quality of the resulting 3-D images allowed an exact differentiation between collagenous and elastic fibers. The analysis of heart valve tissues of patients with cardiomyopathy revealed a dramatic loss of its capability to generate SH (second harmonic), indicating a structural deformation of the collagenous fibers, which was virtually impossible to obtain by routine histological or immunohistological staining. These results indicate that NIR femtosecond laser scanning systems can be employed as novel non-invasive optical technology for 3-D resolved ECM component imaging and in vitro and in vivo tissue diagnosis.

  19. Large-volume optical coherence tomography with real-time correction of geometric distortion artifacts

    CERN Document Server

    Van der Jeught, Sam; Bradu, Adrian; Podoleanu, Adrian Gh; Dirckx, Joris J J

    2012-01-01

    Large-volume optical coherence tomography (OCT)-setups employ scanning mirrors and suffer from non-linear geometric distortion artifacts in which the degree of distortion is determined by the maximum angles over which the mirrors rotate. In this chapter, we describe a straightforward approach to correct for these distortion artifacts, creating an alternative to previously reported ray-tracing schemes that are unable to apply these corrections in real-time. By implementing the proposed 3D recalibration algorithm on the graphics card of a standard computer, this feature can be applied in real-time. We validate the accuracy of the technique using OCT measurements of a highly curved object within a large imaging volume of 12.35 x 10.13 x 2.36 mm^3. The resulting 3D object shape measurements are compared against high-resolution and aberration-free optical profilometry measurements. Maintaining an optical resolution of <10 micron within the sample, both axially and transversally, we realized a real-time, high-re...

  20. En-face full-field optical coherence tomography for fast and efficient fingerprints acquisition

    Science.gov (United States)

    Harms, Fabrice; Dalimier, Eugénie; Boccara, A. Claude

    2014-05-01

    Optical coherence tomography (OCT) has been recently proposed by a number of laboratories as a promising tool for fingerprints acquisitions and for fakes discrimination. Indeed OCT being a non-contact, non-destructive optical method that virtually sections the volume of biological tissues that strongly scatter light it appears obvious to use it for fingerprints. Nevertheless most of the OCT setups have to go through the long acquisition of a full 3D image to isolate an "en-face" image suitable for fingerprint analysis. A few "en-face" OCT approaches have been proposed that use either a complex 2D scanning setup and image processing, or a full-field illumination using a camera and a spatially coherent source that induces crosstalks and degrades the image quality. We show here that Full Field OCT (FFOCT) using a spatially incoherent source is able to provide "en-face" high quality optical sectioning of the fingers skin. Indeed such approach shows a unique spatial resolution able to reveal a number of morphological details of fingerprints that are not seen with competing OCT setups. In particular the cellular structure of the stratum corneum and the epidermis-dermis interface appear clearly. We describe our high-resolution (1 micrometer, isotropic) setup and show our first design to get a large field of view while keeping a good sectioning ability of about 3 micrometers. We display the results obtained using these two setups for fingerprints examination.

  1. High-resolution handheld rigid endomicroscope based on full-field optical coherence tomography

    Science.gov (United States)

    Benoit a la Guillaume, Emilie; Martins, Franck; Boccara, Claude; Harms, Fabrice

    2016-02-01

    Full-field optical coherence tomography (FF-OCT) is a powerful tool for nondestructive assessment of biological tissue, i.e., for the structural examination of tissue in depth at a cellular resolution. Mostly known as a microscopy device for ex vivo analysis, FF-OCT has also been adapted to endoscopy setups since it shows good potential for in situ cancer diagnosis and biopsy guidance. Nevertheless, all the attempts to perform endoscopic FF-OCT imaging did not go beyond lab setups. We describe here, to the best of our knowledge, the first handheld FF-OCT endoscope based on a tandem interferometry assembly using incoherent illumination. A common-path passive imaging interferometer at the tip of an optical probe makes it robust and insensitive to environmental perturbations, and a low finesse Fabry-Perot processing interferometer guarantees a compact system. A good resolution (2.7 μm transverse and 6 μm axial) is maintained through the long distance, small diameter relay optics of the probe, and a good signal-to-noise ratio is achieved in a limited 100 ms acquisition time. High-resolution images and a movie of a rat brain slice have been recorded by moving the contact endoscope over the surface of the sample, allowing for tissue microscopic exploration at 20 μm under the surface. These promising ex vivo results open new perspectives for in vivo imaging of biological tissue, in particular, in the field of cancer and surgical margin assessment.

  2. Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography.

    Science.gov (United States)

    Shen, Liangbo; Carrasco-Zevallos, Oscar; Keller, Brenton; Viehland, Christian; Waterman, Gar; Hahn, Paul S; Kuo, Anthony N; Toth, Cynthia A; Izatt, Joseph A

    2016-05-01

    Intra-operative optical coherence tomography (OCT) requires a display technology which allows surgeons to visualize OCT data without disrupting surgery. Previous research and commercial intrasurgical OCT systems have integrated heads-up display (HUD) systems into surgical microscopes to provide monoscopic viewing of OCT data through one microscope ocular. To take full advantage of our previously reported real-time volumetric microscope-integrated OCT (4D MIOCT) system, we describe a stereoscopic HUD which projects a stereo pair of OCT volume renderings into both oculars simultaneously. The stereoscopic HUD uses a novel optical design employing spatial multiplexing to project dual OCT volume renderings utilizing a single micro-display. The optical performance of the surgical microscope with the HUD was quantitatively characterized and the addition of the HUD was found not to substantially effect the resolution, field of view, or pincushion distortion of the operating microscope. In a pilot depth perception subject study, five ophthalmic surgeons completed a pre-set dexterity task with 50.0% (SD = 37.3%) higher success rate and in 35.0% (SD = 24.8%) less time on average with stereoscopic OCT vision compared to monoscopic OCT vision. Preliminary experience using the HUD in 40 vitreo-retinal human surgeries by five ophthalmic surgeons is reported, in which all surgeons reported that the HUD did not alter their normal view of surgery and that live surgical maneuvers were readily visible in displayed stereoscopic OCT volumes.

  3. Design & development of a galvanometer inspired dual beam optical coherence tomography system for flow velocity quantification of the microvasculature

    OpenAIRE

    McElligott-Daly, Susan; Jonathan, E.; Martin J. Leahy

    2011-01-01

    peer-reviewed This paper reports initial experimentation of a dual beam flow velocity estimation setup based on optical coherence tomography (OCT) for biomedical applications. The proposed work incorporates a low cost switching mechanism (rotating galvanometer mirror) for optical signal discrimination between adjacent fiber channels enabling quasisimultaneous multiple specimen scanning. A cascaded interferometric design is used with two sample output arms orientated in parallel to eacho...

  4. Swept source optical coherence tomography for quantitative and qualitative assessment of dental composite restorations

    Science.gov (United States)

    Sadr, Alireza; Shimada, Yasushi; Mayoral, Juan Ricardo; Hariri, Ilnaz; Bakhsh, Turki A.; Sumi, Yasunori; Tagami, Junji

    2011-03-01

    The aim of this work was to explore the utility of swept-source optical coherence tomography (SS-OCT) for quantitative evaluation of dental composite restorations. The system (Santec, Japan) with a center wavelength of around 1300 nm and axial resolution of 12 μm was used to record data during and after placement of light-cured composites. The Fresnel phenomenon at the interfacial defects resulted in brighter areas indicating gaps as small as a few micrometers. The gap extension at the interface was quantified and compared to the observation by confocal laser scanning microscope after trimming the specimen to the same cross-section. Also, video imaging of the composite during polymerization could provide information about real-time kinetics of contraction stress and resulting gaps, distinguishing them from those gaps resulting from poor adaptation of composite to the cavity prior to polymerization. Some samples were also subjected to a high resolution microfocus X-ray computed tomography (μCT) assessment; it was found that differentiation of smaller gaps from the radiolucent bonding layer was difficult with 3D μCT. Finally, a clinical imaging example using a newly developed dental SS-OCT system with an intra-oral scanning probe (Panasonic Healthcare, Japan) is presented. SS-OCT is a unique tool for clinical assessment and laboratory research on resin-based dental restorations. Supported by GCOE at TMDU and NCGG.

  5. New approach for mathematical problems of the optical tomography of highly scattering (biological) objects

    Science.gov (United States)

    Lyubimov, Vladimir V.; Kravtsenyuk, Olga V.; Murzin, Alexander G.

    1999-06-01

    We present a new method which we call the method of Photon Average Trajectory (PAT). This method provides an image reconstruction in real-time operation mode obtaining the images of superresolution quality. It is shown that time- resolved solutions of unsteady-state radiation transfer and diffusion equations permit to separate out in an explicit from the distribution function P for the probability density for a signal passage through various internal points of studied body while signal propagates from a source point to a detector point. The function P has a characteristic view of Baye's formula. Our analysis has allowed to establish a number of generalized rules of analytical derivation of the function P for highly scattering bodies of arbitrary shapes and for different measurement conditions. It is also shown that, the shadows at the body surface induced by internal macroinhomogeneities can be represented in terms of trajectory integral along the PAT. This approach for the optical tomography using multiply scattered light makes it similar to the conventional computer tomography. In this representation the integrated is the generalized distribution function of internal macroinhomogeneities averaged over the instantaneous values of the distribution P and normalized to the relative velocity of the center movement along the PAT of the distribution P.

  6. Measurement of ciliary beat frequency using ultra-high resolution optical coherence tomography

    Science.gov (United States)

    Chen, Jason J.; Jing, Joseph C.; Su, Erica; Badger, Christopher; Coughlan, Carolyn A.; Chen, Zhongping; Wong, Brian J. F.

    2016-02-01

    Ciliated epithelial cells populate up to 80% of the surface area of the human airway and are responsible for mucociliary transport, which is the key protective mechanism that provides the first line of defense in the respiratory tract. Cilia beat in a rhythmic pattern and may be easily affected by allergens, pollutants, and pathogens, altering ciliary beat frequency (CBF) subsequently. Diseases including cystic fibrosis, chronic obstructive pulmonary disease, and primary ciliary dyskinesia may also decrease CBF. CBF is therefore a critical component of respiratory health. The current clinical method of measuring CBF is phase-contrast microscopy, which involves a tissue biopsy obtained via brushing of the nasal cavity. While this method is minimally invasive, the tissue sample must be oriented to display its profile view, making the visualization of a single layer of cilia challenging. In addition, the conventional method requires subjective analysis of CBF, e.g., manually counting by visual inspection. On the contrary, optical coherence tomography (OCT) has been used to study the retina in ophthalmology as well as vasculature in cardiology, and offers higher resolution than conventional computed tomography and magnetic resonance imaging. Based on this technology, our lab specifically developed an ultra-high resolution OCT system to image the microstructure of the ciliated epithelial cells. Doppler analysis was also performed to determine CBF. Lastly, we also developed a program that utilizes fast Fourier transform to determine CBF under phase-contrast microscopy, providing a more objective method compared to the current method.

  7. Microvascular anastomosis in rodent model evaluated by Fourier domain Doppler optical coherence tomography

    Science.gov (United States)

    Huang, Yong; Tong, Dedi; Zhu, Shan; Wu, Lehao; Ibrahim, Zuhaib; Lee, WP Andrew; Brandacher, Gerald; Kang, Jin U.

    2014-03-01

    Vascular and microvascular anastomosis are critical components of reconstructive microsurgery, vascular surgery and transplant surgery. Imaging modality that provides immediate, real-time in-depth view and 3D structure and flow information of the surgical site can be a great valuable tool for the surgeon to evaluate surgical outcome following both conventional and innovative anastomosis techniques, thus potentially increase the surgical success rate. Microvascular anastomosis for vessels with outer diameter smaller than 1.0 mm is extremely challenging and effective evaluation of the outcome is very difficult if not impossible using computed tomography (CT) angiograms, magnetic resonance (MR) angiograms and ultrasound Doppler. Optical coherence tomography (OCT) is a non-invasive high-resolution (micron level), high-speed, 3D imaging modality that has been adopted widely in biomedical and clinical applications. Phaseresolved Doppler OCT that explores the phase information of OCT signals has been shown to be capable of characterizing dynamic blood flow clinically. In this work, we explore the capability of Fourier domain Doppler OCT as an evaluation tool to detect commonly encountered post-operative complications that will cause surgical failure and to confirm positive result with surgeon's observation. Both suture and cuff based techniques were evaluated on the femoral artery and vein in the rodent model.

  8. Repeatability of swept-source optical coherence tomography retinal and choroidal thickness measurements in neovascular age-related macular degeneration

    DEFF Research Database (Denmark)

    Hanumunthadu, Daren; Ilginis, Tomas; Restori, Marie

    2017-01-01

    BACKGROUND: The aim was to determine the intrasession repeatability of swept-source optical coherence tomography (SS-OCT)-derived retinal and choroidal thickness measurements in eyes with neovascular age-related macular degeneration (nAMD). METHODS: A prospective study consisting of patients with...

  9. Normative data of outer photoreceptor layer thickness obtained by software image enhancing based on Stratus optical coherence tomography images

    DEFF Research Database (Denmark)

    Christensen, U.C.; Kroyer, K.; Thomadsen, J.

    2008-01-01

    Aim: To present normative data of outer photoreceptor layer thickness obtained by a new semiautomatic image analysis algorithm operating on contrast-enhanced optical coherence tomography (OCT) images. Methods: Eight Stratus OCT3 scans from identical retinal locations from 25 normal eyes were regi...

  10. Guided access cavity preparation using cone-beam computed tomography and optical surface scans - an ex vivo study

    DEFF Research Database (Denmark)

    Buchgreitz, J; Buchgreitz, M; Mortensen, D

    2016-01-01

    AIM: To evaluate ex vivo, the accuracy of a preparation procedure planned for teeth with pulp canal obliteration (PCO) using a guide rail concept based on a cone-beam computed tomography (CBCT) scan merged with an optical surface scan. METHODOLOGY: A total of 48 teeth were mounted in acrylic bloc...

  11. Retinal nerve fiber layer thickness in subgroups of multiple sclerosis, measured by optical coherence tomography and scanning laser polarimetry

    NARCIS (Netherlands)

    T.A.M. Siepman (Theodora); M. Wefers Bettink-Remeijer (Marijke); R.Q. Hintzen (Rogier)

    2010-01-01

    textabstractOptical coherence tomography (OCT) and scanning laser polarimetry (GDx ECC) are non-invasive methods used to assess retinal nerve fiber layer (RNFL) thickness, which may be a reliable tool used to monitor axonal loss in multiple sclerosis (MS). The objectives of this study are (1) to com

  12. Multi-modal adaptive optics system including fundus photography and optical coherence tomography for the clinical setting.

    Science.gov (United States)

    Salas, Matthias; Drexler, Wolfgang; Levecq, Xavier; Lamory, Barbara; Ritter, Markus; Prager, Sonja; Hafner, Julia; Schmidt-Erfurth, Ursula; Pircher, Michael

    2016-05-01

    We present a new compact multi-modal imaging prototype that combines an adaptive optics (AO) fundus camera with AO-optical coherence tomography (OCT) in a single instrument. The prototype allows acquiring AO fundus images with a field of view of 4°x4° and with a frame rate of 10fps. The exposure time of a single image is 10 ms. The short exposure time results in nearly motion artifact-free high resolution images of the retina. The AO-OCT mode allows acquiring volumetric data of the retina at 200kHz A-scan rate with a transverse resolution of ~4 µm and an axial resolution of ~5 µm. OCT imaging is acquired within a field of view of 2°x2° located at the central part of the AO fundus image. Recording of OCT volume data takes 0.8 seconds. The performance of the new system is tested in healthy volunteers and patients with retinal diseases.

  13. Assessment of the Optic Disc Morphology Using Spectral-Domain Optical Coherence Tomography and Scanning Laser Ophthalmoscopy

    Directory of Open Access Journals (Sweden)

    Pilar Calvo

    2014-01-01

    Full Text Available Objective. To compare the equivalent optic nerve head (OHN parameters obtained with confocal scanning laser ophthalmoscopy (HRT3 and spectral-domain optical coherence tomography (OCT in healthy and glaucoma patients. Methods. One hundred and eighty-two consecutive healthy subjects and 156 patients with open-angle glaucoma were divided into 2 groups according to intraocular pressure and visual field outcomes. All participants underwent imaging of the ONH with the HRT3 and the Cirrus OCT. The ONH parameters and the receiver operating characteristic (ROC curves were compared between both groups. Results. Mean age did not differ between the normal and glaucoma groups (59.55 ± 9.7 years and 61.05 ± 9.4 years, resp.; P=0.15. Rim area, average cup-to-disc (C/D ratio, vertical C/D ratio, and cup volume were different between both instruments (P<0.001. All equivalent ONH parameters, except disc area, were different between both groups (P<0.001. The best areas under the ROC curve were observed for vertical C/D ratio (0.980 for OCT and 0.942 for HRT3; P=0.11. Sensitivities at 95% fixed-specificities of OCT parameters were higher than those of HRT3. Conclusions. Equivalent ONH parameters of Cirrus OCT and HRT3 are different and cannot be used interchangeably. ONH parameters measured with OCT yielded a slightly better diagnostic performance.

  14. Diffuse optical fluorescence tomography using time-resolved data acquired in transmission

    Science.gov (United States)

    Leblond, Frederic; Fortier, Simon; Friedlander, Michael P.

    2007-02-01

    We present an algorithm using data acquired with a time-resolved system with the goal of reconstructing sources of fluorescence emanating from the deep interior of highly scattering biological tissues. A novelty in our tomography algorithm is the integration of a light transport model adapted to rodent geometries. For small volumes, our analysis suggest that neglecting the index of refraction mismatch between diffusive and non-diffusive regions, as well as the curved nature of the boundary, can have a profound impact on fluorescent images and spectroscopic applications relying on diffusion curve fitting. Moreover, we introduce a new least-squares solver with bound constraints adapted for optical problems where a physical non-negative constraint can be imposed. Finally, we find that maximizing the time-related information content of the data in the reconstruction process significantly enhances the quality of fluorescence images. Preliminary noise propagation and detector placement optimization analysis are also presented.

  15. Advances in broad bandwidth light sources for ultrahigh resolution optical coherence tomography.

    Science.gov (United States)

    Unterhuber, A; Povazay, B; Bizheva, K; Hermann, B; Sattmann, H; Stingl, A; Le, T; Seefeld, M; Menzel, R; Preusser, M; Budka, H; Schubert, Ch; Reitsamer, H; Ahnelt, P K; Morgan, J E; Cowey, A; Drexler, W

    2004-04-07

    Novel ultra-broad bandwidth light sources enabling unprecedented sub-2 microm axial resolution over the 400 nm-1700 nm wavelength range have been developed and evaluated with respect to their feasibility for clinical ultrahigh resolution optical coherence tomography (UHR OCT) applications. The state-of-the-art light sources described here include a compact Kerr lens mode locked Ti:sapphire laser (lambdaC = 785 nm, delta lambda = 260 nm, P(out) = 50 mW) and different nonlinear fibre-based light sources with spectral bandwidths (at full width at half maximum) up to 350 nm at lambdaC = 1130 nm and 470 nm at lambdaC = 1375 nm. In vitro UHR OCT imaging is demonstrated at multiple wavelengths in human cancer cells, animal ganglion cells as well as in neuropathologic and ophthalmic biopsies in order to compare and optimize UHR OCT image contrast, resolution and penetration depth.

  16. Evaluation of effective noise bandwidth for broadband optical coherence tomography operation.

    Science.gov (United States)

    Cernat, Ramona; Dobre, George M; Bradu, Adrian; Podoleanu, Adrian Gh

    2009-04-01

    Key noise parameters in optical coherence tomography (OCT) systems employing splitters with a nonflat spectral response are evaluated using a supercontinuum fiber laser source with a spectrum of 450 nm-1700 nm and a time domain OCT architecture based on 1300 nm fiber splitters. The spectral behavior of the splitter leading to balanced detection is measured over a range of 300 nm. Because of spectrally different signals at the balanced detector input a residual excess photon noise term results. A rigorous treatment of this noise term [Appl. Opt.43, 4802 (2004)] introduced two new quantities that take into account the spectral properties of the coupler. In this report, we have evaluated these two noise bandwidth quantities and comparatively assessed the noise behavior predicted by the classical theory with the theory based on the two new noise bandwidths. We show that under certain operating parameters, the additional excess photon noise is twice that predicted for a coupler with a flat spectral response.

  17. Utilizing optical coherence tomography for CAD/CAM of indirect dental restorations

    Science.gov (United States)

    Chityala, Ravishankar; Vidal, Carola; Jones, Robert

    Optical Coherence Tomography (OCT) has seen broad application in dentistry including early carious lesion detection and imaging defects in resin composite restorations. This study investigates expanding the clinical usefulness by investigating methods to use OCT for obtaining three-dimensional (3D) digital impressions, which can be integrated to CAD/CAM manufacturing of indirect restorations. 3D surface topography `before' and `after' a cavity preparation was acquired by an intraoral cross polarization swept source OCT (CP-OCT) system with a Micro-Electro-Mechanical System (MEMS) scanning mirror. Image registration and segmentation methods were used to digitally construct a replacement restoration that modeled the original surface morphology of a hydroxyapatite sample. After high resolution additive manufacturing (e.g. polymer 3D printing) of the replacement restoration, micro-CT imaging was performed to examine the marginal adaptation. This study establishes the protocol for further investigation of integrating OCT with CAD/CAM of indirect dental restorations.

  18. Optical coherence tomography assessment of a complex bifurcation lesion treated with double kissing Crush technique

    Science.gov (United States)

    Cai, Jin-Zan; Zhang, Yao-Jun; Xu, Tian; Zhu, Yong-Xiang; Mao, Chen-Yu; Bourantas, Christos V.; Crake, Tom; Chen, Shao-Liang

    2017-01-01

    Abstract The DEFINITION (Impact of the complexity of bifurcation lesions treated with drug-eluting stents) study has provided a novel classification to evaluate the complexity of coronary bifurcation lesion according to coronary angiography, but angiographic imaging due to its low resolution and inherited limitation may result in an inaccurate adjudication. We used optical coherence tomography (OCT) to further evaluate the coronary characteristics in a patient with “simple” bifurcation lesion which was classified by the DEFINITION criteria. However, a “complex” bifurcation lesion was defined and confirmed according to the OCT results. A double kissing Crush stenting approach was adopted to treat this “complex” case finally. The immediate and long-term angiographic and OCT results were excellent. OCT may be useful imaging modality to classify complexity of coronary bifurcation lesion and subsequently guide its treatment strategy. PMID:28072714

  19. Microscope-integrated optical coherence tomography for image-aided positioning of glaucoma surgery

    Science.gov (United States)

    Li, Xiqi; Wei, Ling; Dong, Xuechuan; Huang, Ping; Zhang, Chun; He, Yi; Shi, Guohua; Zhang, Yudong

    2015-07-01

    Most glaucoma surgeries involve creating new aqueous outflow pathways with the use of a small surgical instrument. This article reported a microscope-integrated, real-time, high-speed, swept-source optical coherence tomography system (SS-OCT) with a 1310-nm light source for glaucoma surgery. A special mechanism was designed to produce an adjustable system suitable for use in surgery. A two-graphic processing unit architecture was used to speed up the data processing and real-time volumetric rendering. The position of the surgical instrument can be monitored and measured using the microscope and a grid-inserted image of the SS-OCT. Finally, experiments were simulated to assess the effectiveness of this integrated system. Experimental results show that this system is a suitable positioning tool for glaucoma surgery.

  20. Endoscopic swept-source optical coherence tomography based on a two-axis microelectromechanical system mirror

    Science.gov (United States)

    Wang, Donglin; Fu, Linlai; Wang, Xin; Gong, Zhongjian; Samuelson, Sean; Duan, Can; Jia, Hongzhi; Ma, Jun Shan; Xie, Huikai

    2013-08-01

    A microelectromechanical system (MEMS) mirror based endoscopic swept-source optical coherence tomography (SS-OCT) system that can perform three-dimensional (3-D) imaging at high speed is reported. The key component enabling 3-D endoscopic imaging is a two-axis MEMS scanning mirror which has a 0.8×0.8 mm2 mirror plate and a 1.6×1.4 mm2 device footprint. The diameter of the endoscopic probe is only 3.5 mm. The imaging rate of the SS-OCT system is 50 frames/s. OCT images of both human suspicious oral leukoplakia tissue and normal buccal mucosa were taken in vivo and compared. The OCT imaging result agrees well with the histopathological analysis.