Purpose: : To demonstrate the depth resolved birefringence imaging of retina using polarization sensitive Fourier domain optical coherence tomography system. Methods: : Fiber-based polarization sensitive Fourier domain optical coherence tomography system was developed. Fiber birefringence was compensated with surface reflection from the retina. Phase retardation and orientation of the birefringence can be measured with Jones matrix based algorism in addition to conventional cross sectional OCT. Synchronized two line-CCD cameras allow high-speed measurement of birefringence of retina in vivo. Results: : Retinal phase retardation map was visualized as depth-resolved image. Retinal birefringence tomograph of healthy volunteers were analyzed and compared to earlier literatures; the results of polarization sensitive time domain optical coherence tomography and histological knowledge. Conclusions: : Polarization sensitive Fourier domain optical coherence tomography allowed visualizing depth-resolved ...
TY - JOUR. T1 - Age and retinal nerve fiber layer thickness measured by spectral domain optical coherence tomography.. AU - Lee, Jong Yeon. AU - Hwang, Young Hoon. AU - Lee, Sun Min. AU - Kim, Yong Yeon. PY - 2012/6/1. Y1 - 2012/6/1. N2 - To evaluate the association between age and peripapillary retinal nerve fiber layer (RNFL) thickness measured by Cirrus high-definition (HD) spectral domain optical coherence tomography (OCT) in healthy Korean subjects. A total of 302 eyes from 155 healthy Korean subjects (age range, 20 to 79 years) underwent RNFL thickness measurements using the Cirrus HD-OCT. Average, quadrant, and clock-hour RNFL thickness parameters were analyzed in terms of age using linear mixed effect models. Average RNFL demonstrated a slope of -2.1 μm per decade of age (p , 0.001). In quadrant analysis, superior (-3.4 μm/decade, p , 0.001) and inferior (-2.9 μm/decade, p , 0.001) quadrants showed steeper slopes, whereas temporal (-1.1 μm/decade, p , 0.001) and nasal (-1.0 ...
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Previous studies have almost exclusively used standard time-domain optical coherence tomography (TD-OCT, Stratus OCT; Carl Zeiss Meditec, Dublin, California) as a non-invasive retinal ocular imaging technique to measure structural changes in the axonal integrity of the retinal nerve fibre layer (RNFL) in patients with glaucoma, various optic neuropathies, optic neuritis (ON) and/or multiple sclerosis (MS).1-3 … ...
We demonstrate a novel technique to determine the size of Mie scatterers with high sensitivity. Our technique is based on spectral domain optical coherence tomography measurements of the phase dispersion that is induced by the scattering process. We use both Mie scattering predictions and dispersion measurements of phantoms to show that the scattering dispersion is very sensitive to small changes in the size and/or refractive index of the scatterer. We also show the light scattered from a single sphere is, in some cases, non-minimum phase. Therefore, the phase is independent of the intensity of the scattered light, and both intensity and phase must be measured directly in order to characterize more completely the scattering problem. Phase dispersion measurements may have application to distinguishing the size and refractive index of scattering particles in biological tissue samples.. ©2006 Optical Society of America. Full Article , PDF Article ...
Asejczyk-Widlicka, Magdelena, Schachar, Ronald A. and Pierscionek, Barbara K. (2008) Optical coherence tomography measurements of the fresh porcine eye and response of the outer coats of the eye to volume increase. Journal of Biomedical Optics, 13(2), 024002. ISSN (print) 1083-3668 ...
Purpose: To determine the choroidal thickness (CT) profile in keratoconus (KC) patients using swept-source optical coherence tomography (SS-OCT). Methods: This was a prospective, cross-sectional study. One hundred two eyes of 52 KC patients were studied using Pentacam and SS-OCT. The macular CT profile was created by manually measuring the distance between the retinal pigment epithelium and the choroid-sclera junction on horizontal b-scans at nine different macular locations. The results were compared to 93 eyes of 93 healthy controls. Results: Mean age of the KC group was 34.9 ± 13.5 years and mean axial length (AL) was 24.1 ± 1.3 mm. Mean topographic KC classification (TKC) was 2.0; 39 eyes were classified as early KC (TKC ,1-2), 34 eyes as moderate (TKC 2, 2-3), and 29 as advanced (TKC 3+). Mean subfoveal CT was 383.2 μm in KC patients and 280.5 μm in control group (P , 0.001). CT in KC patients was statistically thicker in all measure locations (P , 0.001). CT in KC eyes decreased with ...
Optical Coherence Tomography Market: Global Historical Growth (2012-2016) & Future Outlook (2017-2024) Demand Analysis & Opportunity Evaluation". The global optical coherence tomography market is segmented into application such as ophthalmology, dermatology, oncology, cardiovascular, dentistry and cancer detection. Among these segments, ophthalmology segment is expected to occupy the top position in overall optical coherence tomography market. Further, the growth of this segment is attributed to various factors such as increasing number of patients affected with eyes disorders such as age-related macular degeneration, diabetic retinopathy, macular edema and others. Apart from this, dermatology segment mask an outstanding CAGR in near future owing to growing skin disorders and continuous technological advancement in the field of optical coherence tomography.. Global optical coherence tomography market is expected to register a 10.9% CAGR over the forecast period. Moreover, the global optical ...
Definition of Optical coherence tomography in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is Optical coherence tomography? Meaning of Optical coherence tomography as a legal term. What does Optical coherence tomography mean in law?
OBJECTIVES: We used optical coherence tomography, which has a resolution of |20 microm, to analyze thin layers of neointima in rapamycin-eluting coronary stents. BACKGROUND: Lack of neointimal coverage has been implicated in the pathogenesis of drug-eluting coronary stent thrombosis. Angiography and intracoronary ultrasound lack the resolution to examine this. METHODS: We conducted a randomized trial in patients receiving polymer-coated rapamycin-eluting stents (Cypher, Cordis, Johnson & Johnson, Miami, Florida) and nonpolymer rapamycin-eluting stents (Yukon, Translumina, Hechingen, Germany) to examine neointimal thickness, stent strut coverage, and protrusion at 90 days. Twenty-four patients (n = 12 for each group) underwent stent deployment and invasive follow-up at 90 days with optical coherence tomography. The primary end point was binary stent strut coverage. Coprimary end points were neointimal thickness and stent strut luminal protrusion. RESULTS: No patient had angiographic restenosis. For
We describe a bidirectional color Doppler Fourier-domain optical coherence tomography system capable of measuring absolute velocities of moving scatterers by illuminating the sample with two linearly and orthogonally polarized beams, incident at a known angle on the sample. The velocity calculation is independent of the exact orientation of the velocity vector in the detection plane. First measurements were performed on a rotating disk driven at well-defined velocities and tilted by various small angles. Our results indicate a high correlation between preset and calculated velocities (correlation coefficient 0.999) and the independency of these velocities from the tilting angle of the disk. We demonstrate that bidirectional color Doppler optical coherence tomography allows for the measurement of absolute blood flow values in vivo in human retinal vessels.. © 2008 Optical Society of America. Full Article , PDF Article ...
Imaging choroidal neovascular membrane using en face swept-source optical coherence tomography angiography Magdy Moussa,1,2 Mahmoud Leila,3 Hagar Khalid1,2 1Ophthalmology Department, Faculty of Medicine, Tanta University, Tanta, Egypt; 2MEDIC Eye Center, Tanta, Egypt; 3Retina Department, Research Institute of Ophthalmology, Giza, Egypt Purpose: The aim of this study was to assess the efficacy of swept-source optical coherence tomography angiography (SS-OCTA) in delineating the morphology of choroidal neovascular membrane (CNV). Patients and methods: This was a retrospective observational case series reviewing clinical data and fundus fluorescein angiography (FFA), swept-source optical coherence tomography (SS-OCT), and SS-OCTA images of patients with CNV and comparing the findings. The swept-source technology enables deeper penetration and superior axial resolution. The incorporated blood flow detection algorithm, optical coherence tomography angiography ratio analysis (OCTARA), enables visualization
Purpose: The purpose of this study was to cluster the test points of the combined 24-2 and 10-2 visual fields (VFs) and circumpapillary retinal nerve fiber layer thickness (cpRNFLT) sectors using explanatory factor analyses (EFAs). The correlations between the VF clusters and cpRNFLT clusters were determined, and a new function-structure relationship map was determined. Methods: Two hundred fifty-four eyes of 166 subjects (13 normal eyes and 241 eyes with glaucoma) were studied retrospectively. All eyes had an axial length ,27 mm and had undergone 24-2 and 10-2 VF tests using the Swedish Interactive Threshold Algorithm (SITA-standard) and cpRNFLT examinations by spectral domain optical coherence tomography within a 3-month period. Explanatory factor analysis was performed to group the 116 test points of the combined 24-2/10-2 VF test grids into a smaller number of VF clusters. Another EFA was performed to cluster the 24 cpRNFLT sectors. The correlations between the VF clusters and the cpRNFLT ...
Authors: Ian C. Han, MD1; S. Scott Whitmore, PhD1; D. Brice Critser, BS, CRA1; Edwin M. Stone, MD, PhD1. Author Affiliations: 1Institute for Vision Research, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242. Purpose: Choroideremia is an X-linked condition characterized by profound choroidal thinning and outer retinal loss which typically begin peripherally and spare the central macula until later in the disease course. The depth of imaging and wide field of view enabled by swept-source optical coherence tomography (SS-OCT) and angiography (SS-OCTA) may be advantageous for characterizing the extent of pathology deep to the choroid and beyond the macula. We aim to describe SS-OCT and SS-OCTA findings in a cohort of patients with choroideremia. Methods: This is a retrospective, cross-sectional study of consecutive patients with molecularly-confirmed choroideremia seen at a tertiary referral center from September 12, 2017 to September 11, 2018. All patients ...
The Worldwide Optical Coherence Tomography Market is growing with the rapid pace; mainly due the burgeoning Healthcare Sector. According to a recent study report published by the Market Research Future, The World Optical Coherence Tomography Market is booming and expected to gain prominence over the forecast period. The Market is forecasted to demonstrate a huge growth by 2023, surpassing its previous growth records in terms of value & volume. The World Market research report of Optical Coherence Tomography is expected to reach US$ 1.59 billion in 2023 from US$ 0.14 billion in 2016 with a CAGR of approximately 8.2% during the forecast period 2017-2023.. Market Research Future published new report, titled "Optical Coherence Tomography Market -Research Report: Forecast to 2023".. Some of the Key Players in this market are: Carl Zeiss Meditec AG, Heidelberg Engineering GmbH and Agfa Healthcare. Other players in this market are: Imalux Corporation, Michelson Diagnostics, Novacam Technologies Inc. ...
The Worldwide Optical Coherence Tomography Market is growing with the rapid pace; mainly due the burgeoning Healthcare Sector. According to a recent study report published by the Market Research Future, The World Optical Coherence Tomography Market is booming and expected to gain prominence over the forecast period. The Market is forecasted to demonstrate a huge growth by 2023, surpassing its previous growth records in terms of value & volume. The World Market research report of Optical Coherence Tomography is expected to reach US$ 1.59 billion in 2023 from US$ 0.14 billion in 2016 with a CAGR of approximately 8.2% during the forecast period 2017-2023.. Market Research Future published new report, titled "Optical Coherence Tomography Market -Research Report: Forecast to 2023".. Some of the Key Players in this market are: Carl Zeiss Meditec AG, Heidelberg Engineering GmbH and Agfa Healthcare. Other players in this market are: Imalux Corporation, Michelson Diagnostics, Novacam Technologies Inc. ...
The development of high-resolution and high-speed OCT technology as well as OCT compatible catheter/endoscopes and other delivery systems represent the future of OCT imaging clinical applications. The unique capabilities of OCT imaging make it an ideal choice for the diagnosis and clinical management of many diseases. In 2015, the total revenue of the intravascular OCT market was $128 million; it increased to $140 million in 2016. The primary factors contributing in the growth of the Optical Coherence Tomography (OCT) market is growing aging population and extensive application scope of the technology. Moreover, technological benefits of OCT such as ability to visualize in-depth structures of the eye, mucosal membranes, surface tissues and vascular systems; is significantly driving the growth of the Optical Coherence Tomography (OCT) market. Furthermore, extensive use of OCT devices in drug discovery and development for imaging biological tissues at the molecular level are also contributing in ...
Macular edema is a common cause of visual loss at uveitic patients. The aim of our study was to investigate retinal and choroidal thickness at the macula in anterior (AU) and intermediate (IMU) uveitis and in healthy individuals using spectral domain optical coherence tomography (SD-OCT). Case-control study of 21 patients with AU and 23 patients with IMU and 34 age-matched healthy controls was performed with Spectralis SD-OCT (Heidelberg Engineering, Germany). High resolution SD-OCT scans and macular mapping were applied for automated measurement of retinal thickness. Standardized, masked manual measurement of the choroidal thickness was performed in the center of the ETDRS fields on enhanced depth imaging (EDI) scans. Evaluation of central retinal subfield thickness, 3 mm and 6 mm perifoveal rings was performed in the corresponding ETDRS zones in patient groups. The mean central retinal subfield thickness was significantly higher in IMU (368.65 ± 115.88 μm, p = 0.0003), but not significantly
Purpose: To describe a technique to obtain combined images of vitreoretinal and choroidal structures using spectral-domain (SD) optical coherence tomography (OCT) and to evaluate applicability in normal eyes and limitations in eyes with cataract. Design: Prospective, observational case series. Methods: Three different foveal scans, including conventional SD OCT, enhanced depth imaging OCT and the novel method called combined depth imaging (CDI) OCT, were obtained in 42 eyes of healthy volunteers and in 26 eyes with cataract using the Heidelberg Spectralis HRA (Heidelberg Engineering). The CDI OCT images were obtained manually using an image modification process that enhances the vitreoretinal interface first and then the choroid, while averaging 100 separate OCT scans. The visualization of the inner border of the preretinal pocket and the outer border of the choroid was graded by independent masked observers for each OCT scan method. Results: The CDI technique was able to create a good-quality ...
Computerized Assessment of Intraretinal and Subretinal Fluid Regions in Spectral-Domain Optical Coherence Tomography Images of the Retina
Optical coherence tomography (OCT) is an imaging method which can image with micrometer-scale resolution up to a few millimeters deep into, for example, living biological tissues and preserved tissue samples. An improved apparatus and image reconstruction algorithm for parallel Fourier Domain OCT which greatly eases requirements for interferometer stability and also allows for more efficient parallel image acquisition is provided. The apparatuses and algorithms reconstruct images from interfered, low-coherence, multiwave length signals having a π radian phase difference relative to one another. Other numbers of signals and other phase differences may be alternatively used, with some combinations resulting in higher resolution and image stability. The apparatus also eliminates a need for bulk optics to modulate a phase delay in a reference arm of the optical path. Images may be reconstructed using two spectrometers, where each is coupled to a detector array such as a photodiode array.
Color Doppler optical coherence tomography (CDOCT) is a noninvasive optical imaging technique for micro-meter-scale physiological flow mapping simultaneously with morphological optical coherence tomography imaging. We have developed a novel CDOCT signal-processing strategy capable of imaging physiological flow rates at 8 frames/s. Our new strategy features hardware-implemented digital autocorrelation across subsequent scans, permitting us to measure 300-Hz-8-kHz Doppler shifts upon signals of 0.6-MHz bandwidth. The performance of the CDOCT system was demonstrated in a flow phantom and in vivo in Xenopus laevis.. © 2002 Optical Society of America. Full Article , PDF Article ...
Christensen UC, Krøyer K, Sander B, Larsen M, la Cour M. Ophthalmology. 2009 Dec;116(12):2430-6. Christensen UC, Krøyer K, Sander B, Jorgensen TM, Larsen M, la Cour M.Macular morphology and visual acuity after macular hole surgery with or without internal limiting membrane peeling. Br J Ophthalmol. 2010 Jan;94(1):41-7 Fujiwara T, Imamura Y, Margolis R, Slakter JS, Spaide RF. Enhanced depth imaging optical coherence tomography of the choroid in highly myopic eyes. Am J Ophthalmol. 2009 Sep;148(3):445-50. Hirata M, Tsujikawa A, Matsumoto A, Hangai M, Ooto S, Yamashiro K, Akiba M, Yoshimura N. Macular choroidal thickness and volume in normal subjects measured by swept-source optical coherence tomography. Invest Ophthalmol Vis Sci. 2011 Jul 1;52(8):4971-8 Marschall S, Sander B, Mogensen M, Jørgensen TM, Andersen PE. Optical coherence tomography-current technology and applications in clinical and biomedical research. Anal Bioanal Chem. 2011 Jul;400(9):2699-720. Sander B, Larsen M, Thrane L, ...
Purpose. We determined ocular and systemic factors influencing macular thickness measured by spectral-domain optical coherence tomography (SD-OCT) in a population-based sample of healthy eyes. Methods. We recruited 490 healthy Chinese adults, aged 40 to 80 years, from the Singapore Chinese Eye Study, a population-based survey. All participants underwent a comprehensive eye examination and a standardized interview. The SD-OCT (Cirrus HD-OCT, software version 6.0) was used to measure a range of macular thickness parameters (central foveal subfield thickness, average inner macular thickness, average outer macular thickness, overall average macular thickness, and overall macular cube volume). Linear regression analyses were performed to examine the effects of various ocular and systemic factors on macular thickness. Results. The mean (standard deviation) age of the subjects was 53.17 (6.14) years and 50.0% of them were male. The mean central foveal subfield, average inner, and average outer macular ...
A study of retinal microvascular changes in Diabetic Macular Edema using the swept - source optical coherence tomography angiography (OCTA) after being treated
A combined ultrahigh resolution optical coherence tomography (UHROCT) and a electroretinography (ERG) system is presented for simultaneous imaging of the retinal structure and physiological response to light stimulation in the rodent eye. The 1060-nm UHROCT system provides ~3×5 µm (axial×lateral) resolution in the rat retina and time resolution of 22 µs. A custom-designed light stimulator integrated into the UHROCT imaging probe provides light stimuli with user-selected color, duration, and intensity. The performance of the combined system is demonstrated in vivo in healthy rats, and in a rat model of drug-induced outer retinal degeneration. Experimental results show correlation between the observed structural and physiological changes in the healthy and degenerated retina ...
TY - JOUR. T1 - Automated detection of shadow artifacts in optical coherence tomography angiography. AU - Camino, Acner. AU - Yali, Jia. AU - Yu, Jeffrey. AU - Wang, Jie. AU - Liu, Liang. AU - Huang, David. PY - 2019/3/1. Y1 - 2019/3/1. N2 - Frequently, when imaging retinal vasculature with optical coherence tomography angiography (OCTA) in diseased eyes, there are unavoidable obstacles to the propagation of light such as vitreous floaters or the pupil boundary. These obstacles can block the optical coherence tomography (OCT) beam and impede the visualization of the underlying retinal microcirculation. Detecting these shadow artifacts is especially important in the quantification of metrics that assess retinal disease progression because they might masquerade as regional perfusion loss. In this work, we present an algorithm to identify shadowed areas in OCTA of healthy subjects as well as patients with diabetic retinopathy, uveitis and age-related macular degeneration. The aim is to exclude ...
Ivan Bravo Gonzalo (Speaker), Michael Maria (Other), Rasmus Dybbro Engelsholm (Other), Thomas Feuchter (Other), Lasse Leick (Other), Peter Morten Moselund (Other), Adrian Podoleanu (Other), Bang, O. (Other ...
This program, entitled Advanced Technologies for Structural and Functional Optical Coherence Tomography, is a collaborative effort between investigators at the Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics; Dr. David Boas, Associate Professor in Radiology, Harvard Medical School at the Massachusetts General Hospital, Martinos Center for Biomedical Imaging; and Dr. Jay Duker, Director, New England Eye Center, Professor and Chair of Ophthalmology, Tufts University School of Medicine. The objective of this program is to develop and apply advanced optical coherence tomography (OCT) technologies for ultrahigh resolution and functional imaging in biomedical applications.
... ISEC employs the Carl Zeiss Meditec Stratus OCT for detailed cross sectional imaging of the eye. The OCT incorporates optical coherence tomography technology to provide comprehensive imaging and measurement of glaucoma and retinal disease. Currently, Stratus OCT is the gold standard in vivo imaging device for the posterior segment and offers proven reproducibility for disease management.. The Stratus OCT provides real-time cross-sectional images and quantitative analysis of retinal features to optimize the diagnosis and monitoring of retinal disease and for enhanced pre- and post-therapy assessment. The device is beneficial for evaluation of cataract patients, pre- and post-operatively, and for the assessment of early signs of glaucoma and glaucomatous change.. Retinal Nerve Fiber Layer (RNFL) Analysis. Circular scans around the optic nerve head capture RNFL measurement of the peripapillary region. Analyses provide comparison of measurements to a normative ...
Most patients of established retinitis pigmentosa (RP) have subnormal peripheral vision and heavily rely on central vision for their daily activities. Central visual acuity is dependent on photoreceptor survival at the macula. Identification of structural changes that precede visual loss is essential. The aim of this study was to correlate the Spectral Domain-Optical Coherence Tomography (SD-OCT) characteristics with visual acuity in patients with typical RP. This was a retrospective, observational case series of 224 eyes of 113 RP patients conducted a tertiary eye care center. SD-OCT imaging was done for all eyes. Central retinal thickness (CRT), photoreceptor outer segment length (PROS), foveal outer segment pigment epithelial thickness (FOSPET) and ellipsoid zone (EZ) extent were measured. A new variable, FOSPET-PROS ratio (FPR), obtained by dividing FOSPET by PROS is defined and correlated to corrected distance visual acuity (CDVA) in logMAR using linear regression. Out of 113 patients, 71 were
In vivo visualization and quantification of choriocapillaris vascular anatomy is a fundamental step in understanding the relation between choriocapillaris degradation and atrophic retinopathies, including geographic atrophy. We describe a process utilizing ultrahigh-speed swept-source optical coherence tomography and a custom-designed local min-max normalized masking algorithm to extract in vivo anatomical metrics of the choriocapillaris. We used a swept-source optical coherence tomography system with a 1.6 MHz A-scan rate to image ...
TY - JOUR. T1 - Diagnostic capability of 3d peripapillary retinal volume for glaucoma using optical coherence tomography customized software. AU - Liu, Yingna. AU - Jassim, Firas. AU - Braaf, Boy. AU - Khoueir, Ziad. AU - Poon, Linda Yi Chieh. AU - Ben-David, Geulah S.. AU - Papadogeorgou, Georgia. AU - Tsikata, Edem. AU - Simavli, Huseyin. AU - Que, Christian. AU - Lee, Ramon. AU - Shieh, Eric. AU - Vakoc, Benjamin J.. AU - Bouma, Brett E.. AU - De Boer, Johannes F.. AU - Chen, Teresa C.. PY - 2019/8. Y1 - 2019/8. N2 - Précis:The diagnostic capability of peripapillary retinal volume is similar to peripapillary retinal nerve fiber layer thickness for diagnosing glaucoma, but with fewer artifacts.Purpose:To compare the diagnostic capability of 3-dimensional peripapillary retinal volume (RV) versus 2-dimensional peripapillary retinal nerve fiber layer (RNFL) thickness for open-angle glaucoma.Patients and Methods:A retrospective cross-sectional analysis was conducted. A total of 180 subjects (113 ...
Circadian rhythms are endogenous, entrainable oscillations of physical, mental and behavioural processes in response to local environmental cues such as daylight, which are present in the living beings, including humans. Circadian rhythms have been related to cardiovascular function and pathology. However, the role that circadian clock genes play in heart development and function in a whole animal in vivo are poorly understood. The Drosophila cryptochrome (dCry) is a circadian clock gene that encodes a major component of the circadian clock negative feedback loop. Compared to the embryonic stage, the relative expression levels of dCry showed a significant increase (|100-fold) in Drosophila during the pupa and adult stages. In this study, we utilized an ultrahigh resolution optical coherence microscopy (OCM) system to perform non-invasive and longitudinal analysis of functional and morphological changes in the Drosophila heart throughout its post-embryonic lifecycle for the first time. The Drosophila
We report a 10-year-old boy with unusually dense, bilateral central posterior capsule pigmentation associated with the characteristic clinical features of pigment dispersion syndrome, including Krukenbergs spindle and dense trabecular pigmentation in both eyes. There was no history of trauma , laser or intraocular surgeries . The presence of posterior or backward bowing of iris suggested a reverse pupillary block mechanism of pigment dispersion syndrome. Nd Yag laser peripheral iridotomy was performed in both eyes to relieve reverse pupillary block. Anterior segment optical coherence tomography (AS-OCT) showed reversal of iris concavity after laser iridotomy.. ...
Comparison of coronary arterial lumen dimensions on angiography and plaque characteristics on optical coherence tomography images and their changes induced by statin. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
A model that describes the concentration of photothermal (light-to-heat converters) compounds as a function of depth in a turbid medium is developed. The system consists of a pump laser (808 nm modulated at 400 Hz), which heats a photothermal compound, and a phase sensitive spectral domain optical coherence tomography system, which detects the changes in the optical path length of the sample induced by the temperature increase. The model is theoretically derived and the coefficients are empirically determined using solid homogeneous gel phantoms. The model is validated by reconstructing the concentration of a photothermal compound in thick single and double layer solid phantoms ...
Extraction of Layers of Vertebrate Retina from Optical Coherence Tomography Images by using Active Contour Model with Structuring ...
The |i|Journal of Biomedical Optics|/i| (JBO) publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and biomedical research.
We report a versatile imaging system combining scanning laser ophthalmoscopy (SLO) and T-scan based en face ultrahigh resolution optical coherence tomography (OCT). The image carrier is generated using the optical path difference modulation introduced by the X-Y galvo-scanner mirrors specific to en face OCT (without optical modulators in the reference arm). The light source is a compact superluminescent diode based source with 150 nm FWHM spectrum, centered at 890 nm. We demonstrate en face B-scan and C-scan ultrahigh resolution OCT imaging of the human retina in vivo, with an axial resolution of 3.2 μm in tissue. The system is capable of acquiring large lateral size ultrahigh resolution OCT scans of a maximum field size of 20°. The acquisition speed is up to 2 frames/s for both OCT B-scans and C-scans. The measured system sensitivity is more than 98 dB, for a power level to the target of 1 mW and maximum lateral scan size. The C-scans are, to the best of our knowledge, the first and the ...
The ZEISS Cirrus HD-OCT 4000 enable examination of the posterior and anterior of the eye at an extremely fine spatial scale, without surgical biopsy or even any contact with the eye. The Cirrus HD-OCT builds on and refines the retinal imaging technology first introduced with the ZEISS Stratus OCT™. HD-OCT stands for "high-definition optical coherence tomography.". Employing the advanced imaging technology of spectral domain optical coherence tomography, Cirrus HD-OCT acquires OCT data about 70 times faster (27,000 vs. 400 A-scans per second) and with better resolution (5 μm vs. ~10 μm axial resolution in tissue), compared to first-generation OCT technology. Cirrus acquires whole cubes of OCT image data, composed of hundreds of line scans, in about the same time as Stratus acquires a six-line scan. You can view these data cubes in three planes, or through three dimensions, giving you access to an extensive amount of retinal image data in one scan.. The Cirrus HD-OCT with Retinal Nerve Fiber ...
PubMed Central Canada (PMC Canada) provides free access to a stable and permanent online digital archive of full-text, peer-reviewed health and life sciences research publications. It builds on PubMed Central (PMC), the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature and is a member of the broader PMC International (PMCI) network of e-repositories.
TY - JOUR. T1 - Projection-Resolved Optical Coherence Tomography Angiography of Macular Retinal Circulation in Glaucoma. AU - Takusagawa, Hana. AU - Liu, Liang. AU - Ma, Kelly N.. AU - Yali, Jia. AU - Gao, Simon S.. AU - Zhang, Miao. AU - Edmunds, Lorna (Beth). AU - Parikh, Mansi. AU - Tehrani, Shandiz. AU - Morrison, John. AU - Huang, David. PY - 2017. Y1 - 2017. N2 - Purpose: To detect macular perfusion defects in glaucoma using projection-resolved optical coherence tomography (OCT) angiography. Design: Prospective observation study. Participants: A total of 30 perimetric glaucoma and 30 age-matched normal participants were included. Methods: One eye of each participant was imaged using 6 × 6-mm macular OCT angiography (OCTA) scan pattern by 70-kHz 840-nm spectral-domain OCT. Flow signal was calculated by the split-spectrum amplitude-decorrelation angiography algorithm. A projection-resolved OCTA (PR-OCTA) algorithm was used to remove flow projection artifacts. Four en face OCTA slabs were ...
Aims: To determine the frequency distribution of false-positive Stratus optical coherence tomography (OCT) results of healthy eyes in terms of peripapillary location.. Methods: One eye of each of 137 healthy Korean subjects was included. The false-positive rates (FPRs) relating to retinal nerve fibre layer (RNFL) thickness parameters were determined.. Results: Of the 12 clock-hour positions, the 2 and 4 oclock positions showed the highest FPRs of 5.1% and 4.4%, respectively, and 7, 8 and 11 oclock had the lowest FPRs of 0% at ,5% level. At ,1% level, 2 and 6 oclock had an FPR of 0.7%, while the FPR was 0% for all other clock-hours. The FPRs for quadrant thicknesses at ,5% level were: 0.7% for temporal; 0% for superior; 5.1% for nasal; and 2.2% for inferior. At ,1% level, the inferior showed the highest FPR of 0.7%, and the other three quadrants 0%. According to line graph analysis, the 80-120 test point sections had FPRs of 4.4-6.6%, while the 0-40 and 210-256 sections were 0-0.7% at ,5% ...
Fourier domain Optical coherence microscopy (FDOCM) offers excellent sensitivity and high axial resolution to image the structure of biological tissue. The depth information is extracted in parallel and allows very high volume acquisition rates. The present system uses a diffractionless beam, produced with an axicon lens, to achieve high lateral resolution all while maintaining an extended depth of field (xf). The xfOCM signal reveals the spatial distribution of changes of the refractive index in the sample that scatter the incident light. To identify and validate the functionality of the observed structures can proof difficult. In this work the xfOCM setup was interfaced with a fluorescent lifetime imaging (FLIM) system, working in the Fourier domain and measuring the phase offset between the modulated excitation signal and the returned fluorescence intensity. Both the fluorescence amplitude and lifetime are retrieved. The amplitude contains important information due to the selective labeling ...
article{f8b9e269-18db-4a46-8cd7-c506ebb1ac88, abstract = {,b,Abstract in Undetermined,/b,,br/,,br, Background: The performance of glaucoma diagnostic systems could be conceivably improved by the integration of functional and structural test measurements that provide relevant and complementary information for reaching a diagnosis. The purpose of this study was to investigate the performance of data fusion methods and techniques for simple combination of Standard Automated Perimetry (SAP) and Optical Coherence Tomography (OCT) data for the diagnosis of glaucoma using Artificial Neural Networks (ANNs). ,br/,,br, ,br/,,br, Methods: Humphrey 24-2 SITA standard SAP and StratusOCT tests were prospectively collected from a randomly selected population of 125 healthy persons and 135 patients with glaucomatous optic nerve heads and used as input for the ANNs. We tested commercially available standard parameters as well as novel ones (fused OCT and SAP data) that exploit the spatial relationship between ...
ARTICLE{Wintergerst:SREP2020, author = {Wintergerst, Maximilian and Gorgi Zadeh, Shekoufeh and Wiens, Vitalis and Thiele, Sarah and Schmitz-Valckenberg, Steffen and Holz, Frank and Finger, Robert and Schultz, Thomas}, pages = {7395}, title = {Replication and Refinement of an Algorithm for Automated Drusen Segmentation on Optical Coherence Tomography}, journal = {Scientific Reports}, volume = {10}, year = {2020}, abstract = {Here, we investigate the extent to which re-implementing a previously published algorithm for OCT-based drusen quantification permits replicating the reported accuracy on an independent dataset. We refined that algorithm so that its accuracy is increased. Following a systematic literature search, an algorithm was selected based on its reported excellent results. Several steps were added to improve its accuracy. The replicated and refined algorithms were evaluated on an independent dataset with the same metrics as in the original publication. Accuracy of the refined algorithm ...
We describe the spectral domain optical coherence tomography (SD-OCT) findings in three patients with acute syphilitic posterior placoid chorioretinitis (ASPPC). The SD-OCT images demonstrate the pathologic changes in ASPPC with a high level of anatomic detail and may provide information about the pathophysiology of the disease. We report a series of three consecutive patients seen at the Wilmer Eye Institute in 2012 and 2013 who presented with clinical and laboratory findings consistent with a diagnosis of unilateral ASPPC. Two of the three patients had HIV co-infection with good immune recovery. SD-OCT images from their initial (pre-treatment) presentation demonstrated thickening and hyperreflective nodularity of the choroid-retinal pigment epithelium (RPE) complex, with focal disruption of the overlying photoreceptor inner segment-outer segment junction in the areas corresponding to the retinal lesions seen on clinical examination. These changes improved with intravenous antibiotic treatment over a 3
TY - JOUR. T1 - Vascular abnormalities in patients with Stargardt disease assessed with optical coherence tomography angiography. AU - Battaglia Parodi, M. AU - Cicinelli, MV. AU - Rabiolo, A. AU - Pierro, L. AU - Bolognesi, G. AU - Bandello, F. PY - 2017. Y1 - 2017. N2 - Aims To describe the vascular abnormalities in patients affected by Stargardt disease (STGD1) by means of optical coherence tomography angiography (OCT-A). Methods Cross-sectional case series, with the following inclusion criteria: diagnosis of STGD1, clear ocular media, and stable fixation. Patients underwent best-corrected visual acuity (BCVA), biomicroscopy, applanation tonometry, short-wavelength fundus autofluorescence (SW-FAF) (HRA Heidelberg, Germany), 3×3 Swept Source OCT-A (Topcon Corporation, Japan). Foveal avascular zone (FAZ) area was manually outlined and removed from the vessel density analysis (ImageJ). Main outcome was vessel density assessment in the superficial capillary plexus (SCP), in the deep capillary ...
The ability to have accurate and catheter based intravascular imaging provides interventional physicians with invaluable insight into the procedural vascular anatomy [1]. Luminal angiography has long been the gold standard for visualizing the arterial lumen and is routinely used for arterial reconstruction. Nevertheless, the structural composition of diseased arterial beds is not adequately visualized by angiography [2]. Intravascular imaging provides important structural information, which is frequently used for diagnostic and therapeutic decision making during the interventional procedure. The highest resolution source for intravascular imaging, optical coherence tomography (OCT), is a sub-surface imaging modality using near-infrared light [3].. Physicians use OCT to evaluate, characterize and understand intravascular anatomic features of normal and abnormal vessels. OCT accomplishes this via emission of a light source and no additional ioninizig radiation.. Initially, intravascular ultrasound ...