Optical Coherence Tomography
TL;DR: Tomographic imaging is demonstrated in vitro in the peripapillary area of the retina and in the coronary artery, two clinically relevant examples that are representative of transparent and turbid media, respectively.
Abstract: A technique called optical coherence tomography (OCT) has been developed for noninvasive cross-sectional imaging in biological systems. OCT uses low-coherence interferometry to produce a two-dimensional image of optical scattering from internal tissue microstructures in a way that is analogous to ultrasonic pulse-echo imaging. OCT has longitudinal and lateral spatial resolutions of a few micrometers and can detect reflected signals as small as approximately 10(-10) of the incident optical power. Tomographic imaging is demonstrated in vitro in the peripapillary area of the retina and in the coronary artery, two clinically relevant examples that are representative of transparent and turbid media, respectively.
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TL;DR: This document may be broadly used as a standard reference regarding the current state of theIVOCT imaging modality, intended for researchers and clinicians who use IVOCT and analyze IVO CT data.
1,501 citations
Cites background from "Optical Coherence Tomography"
...OCT is a light-based imaging modality that generates high-resolution cross-sectional images of tissue microstructure (3)....
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TL;DR: It is found that changing the amount of metal precursor added to the suspension of Ag nanocubes is a simple means of tuning both the composition and the localized surface plasmon resonance (LSPR) of the metal nanocages.
Abstract: Noble-metal nanocages comprise a novel class of nanostructures possessing hollow interiors and porous walls. They are prepared using a remarkably simple galvanic replacement reaction between solutions containing metal precursor salts and Ag nanostructures prepared through polyol reduction. The electrochemical potential difference between the two species drives the reaction, with the reduced metal depositing on the surface of the Ag nanostructure. In our most studied example, involving HAuCl4 as the metal precursor, the resultant Au is deposited epitaxially on the surface of the Ag nanocubes, adopting their underlying cubic form. Concurrent with this deposition, the interior Ag is oxidized and removed, together with alloying and dealloying, to produce hollow and, eventually, porous structures that we commonly refer to as Au nanocages. This approach is versatile, with a wide range of morphologies (e.g., nanorings, prism-shaped nanoboxes, nanotubes, and multiple-walled nanoshells or nanotubes) available upon...
1,255 citations
TL;DR: Methods for 2-D fundus imaging and techniques for 3-D optical coherence tomography (OCT) imaging are reviewed and aspects of image acquisition, image analysis, and clinical relevance are treated together considering their mutually interlinked relationships.
Abstract: Many important eye diseases as well as systemic diseases manifest themselves in the retina. While a number of other anatomical structures contribute to the process of vision, this review focuses on retinal imaging and image analysis. Following a brief overview of the most prevalent causes of blindness in the industrialized world that includes age-related macular degeneration, diabetic retinopathy, and glaucoma, the review is devoted to retinal imaging and image analysis methods and their clinical implications. Methods for 2-D fundus imaging and techniques for 3-D optical coherence tomography (OCT) imaging are reviewed. Special attention is given to quantitative techniques for analysis of fundus photographs with a focus on clinically relevant assessment of retinal vasculature, identification of retinal lesions, assessment of optic nerve head (ONH) shape, building retinal atlases, and to automated methods for population screening for retinal diseases. A separate section is devoted to 3-D analysis of OCT images, describing methods for segmentation and analysis of retinal layers, retinal vasculature, and 2-D/3-D detection of symptomatic exudate-associated derangements, as well as to OCT-based analysis of ONH morphology and shape. Throughout the paper, aspects of image acquisition, image analysis, and clinical relevance are treated together considering their mutually interlinked relationships.
1,118 citations
Cites background from "Optical Coherence Tomography"
...optical coherence tomography (OCT) to retinal imaging [36],...
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...1) Retinal Layer Detection: The segmentation of retinal layers in OCT scans has been an important goal since OCT’s availability to the ophthalmic community [36] as thickness changes in the layers are one indication of disease status (Section V-A3)....
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...gram determines the intensity at each depth [36]....
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TL;DR: The method, experimental setup, data processing, and images are discussed and it is shown that this technique might be as powerful as other optical coherence tomography techniques in the ophthalmologic imaging field.
Abstract: We present what is to our knowledge the first in vivo tomograms of human retina obtained by Fourier domain optical coherence tomography. We would like to show that this technique might be as powerful as other optical coherence tomography techniques in the ophthalmologic imaging field. The method, experimental setup, data processing, and images are discussed.
1,067 citations
TL;DR: Significantly enhanced drug release from composite hydrogels has been achieved in response to irradiation by light at 1064 nm and the nanoshell-composite hydrogel can release multiple bursts of protein in responseto repeated near-IR irradiation.
Abstract: A thermally sensitive polymer-particle composite that absorbs electromagnetic radiation, and uses the absorbed energy to trigger the delivery of a chemical is disclosed. Metal nanoshells are nanoparticulate materials that are suitable for use in the present composites and can be made according to a process that includes optically tuning or tailoring their maximum optical absorption to any desired wavelength primarily by altering the ratio of the core diameter to the shell thickness. Preferred nanoshells are selected that strongly absorb light in the near-infrared and thus produce heat. These nanoshells are combined with a temperature-sensitive material to provide an implantable or injectable material for modulated drug delivery via external exposure to near-IR light. This invention provides a means to improve the quality of life for persons requiring multiple injections of a drug, such as diabetes mellitus patients.
896 citations
Cites background from "Optical Coherence Tomography"
...One such application is optical coherence tomography (OCT), a process in which the reflections of a near-IR laser source are used to image tissues that lie beneath the skin.(10) Lankenau et al....
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