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    1. Towards automated classification of clinical optical coherence tomography data of dense tissues

      The native contrast of optical coherence tomography (OCT) data in dense tissues can pose a challenge for clinical decision making. Automated data evaluation is one way of enhancing the clinical utility of measurements. Methods for extracting information from structural OCT data are appraised here. A-scan analysis allows characterization of layer thickness and scattering parameters, whereas image analysis renders itself to segmentation, texture and speckle analysis. All fully automated approaches combine pre-processing, feature registration, data reduction, and classification. Pre-processing requires de-noising, feature recognition, normalization and refining. In the current literature, image exclusion criteria, initial parameters, or manual input are common requirements ...
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    2. Imaging of actinic porokeratosis by optical coherence tomography (OCT)

      Imaging of actinic porokeratosis by optical coherence tomography (OCT)
      Disseminated superficial actinic porokeratosis (DSAP) is a rare, genetically heterogeneous skin disorder. We report a case of a 73-year-old female patient who was diagnosed with DSAP by optical coherence tomography (OCT) and histology. During the last 4 years prior to diagnosis, she had developed numerous (pre)malignant lesions of the skin of the lower legs including actinic keratoses, squamous cell carcinomas and Bowen’s disease. DSAP lesions and actinic keratoses were resistant to topical treatment with imiquimod and retinoids, but improved with photodynamic therapy (PDT).
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    3. Visante® anterior segment OCT in a patient with gas bubbles in the anterior chamber after femtosecond laser corneal flap formation

      Abstract  A patient with anterior chamber gas bubbles after LASIK flap formation with femtosecond laser is presented. A 33-year-old male patient had LASIK for myopia with corneal flap formation with IntraLase® FS30 femtosecond laser. In the right eye, air bubbles were observed in anterior chamber after successful flap formation. Laser correction was completed successfully, by Wavelight® Allegretto WaveTM Eye-Q excimer laser, without eye-tracker. Visante® anterior segment optical coherence tomography imaging displayed that the pocket extended to limbal area, with stromal bed thickness of >600 μm at that area. We propose as possible causes of the air bubbles scattering of femtosecond ...
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    4. Optical Coherence Tomography: Technology & Applications (Book)

      Optical Coherence Tomography: Technology & Applications (Book)
      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. A new generation OCT technology has now been developed, representing a quantum leap in 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. These new techniques should not only improve image contrast, but should also enable the differentiation of pathologies via ...
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    5. Using the Light Scattering Component of Optical Intrinsic Signals to Visualize In Vivo Functional Structures of Neural Tissues (Book Chapter)

      Using the Light Scattering Component of Optical Intrinsic Signals to Visualize In Vivo Functional Structures of Neural Tissues (Book Chapter)
      Visualization of changes in reflected light from in vivo brain tissues reveals spatial patterns of neural activity. An important factor which influences the degree of light reflected includes the change in light scattering elicited by neural activation. Microstructures of neural tissues generally cause light scattering, and neural activities are associated with some changes in the microstructures. Here, we show that the optical properties unique to light scattering enable us to visualize spatial patterns of retinal activity non-invasively (FRG: functional retinography), and resolve functional structures in depth (fOCT: functional optical coherence tomography). Content Type ProtocolDOI 10.1007/978-1-59745-543-5_6Authors Uma Maheswari RajagopalanKazushige ...
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    6. Diagnostic Modalities in Diabetic Retinopathy (Book Chapter)

      Diagnostic Modalities in Diabetic Retinopathy (Book Chapter)
      In addition to ophthalmologic examination and retinal fundus photography, diagnostic modalities including fluorescein angiography (FA) and optical coherence tomography (OCT) currently play important roles in the evaluation of patients with diabetic retin- opathy (DR). Fluorescein angiography has been a major diagnostic procedure in the clinical evaluation of DR for several decades. This chapter will review the principles and methodology underlying fluorescein angiography, as well as its specific application to the evaluation of diabetic retinopathy and especially retinal vascular permeability. Although fluorescein angiography provides valuable anatomic and functional information pertaining to the retinal vasculature, it does not provide ultrastructural anatomic detail ...
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    7. Optical coherence tomography in multiple sclerosis; Thickness of the retinal nerve fiber layer as a potential measure of axonal loss and brain atrophy

      Background Axonal distribution within the retinal nerve fiber layer (RNFL) measured by optical coherence tomography (OCT) correlates with axonal viability and integrity. Objective To investigate correlations between RNFL and MRI measures of axonal loss in MS patients. Methods Fifty one remitting-relapsing MS patients, 20 with a history of optic neuritis (MS-ON), 31 without optic neuritis (MS N-ON), and 12 healthy control subjects (HC) were included in the study. RNFL was measured by OCT and brain atrophy was assessed by MRI. Results The average RNFL in the affected eye (AE) in the MS-ON group was significantly lower than the RNFL in ...
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    8. Improved reproducibility of retinal nerve fiber layer thickness measurements with the repeat-scan protocol using the Stratus OCT in normal and glaucomatous eyes

      Abstract Background  Optical coherence tomography has become within the last years an established imaging technique with many applications in ophthalmology, and an important tool which contributes to earlier and more accurate diagnosis of glaucoma. As a consequence, detection sensitivity is highly valued. The aim of this study was to assess the reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness measurements by the Stratus Optical Coherence Tomograph (OCT) using the Fast- and Repeat-scan protocols in normal and glaucomatous eyes. Methods  In the clinical setting, RNFL thickness measurements were obtained from a control group of 40 subjects, consisting of 20 normal ...
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    9. Identification of Layers in a Tomographic Image of an Eye Based on the Canny Edge Detection

      In the paper we present an algorithm for the identification of retina layers using the Canny edge detection for images obtained with OCT (Optical Coherence Tomography) Copernicus. The developed algorithm is an extension of the approaches covered in [4] and allows the identification and detection of hyaline-retinal border layers, the retina and other. The algorithm was implemented in the Matlab environment and the C language. Content Type Book ChapterDOI 10.1007/978-3-540-68168-7_26Authors Robert Koprowski, University of Silesia Faculty of Computer Science and Materials Science Institute of Computer Science, Department of Biomedical Computer Systems ul. Bedzinska 39 41-200 SosnowiecZygmunt Wrobel, University ...
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    10. Optical Coherence Tomography Imaging for Evaluating the Photobiomodulation Effects on Tissue Regeneration in Periodontal Tissue

      Optical Coherence Tomography (OCT) is a noninvasive method for imaging dental microstructure which has the potential of evaluating the health of periodontal tissue. OCT provides an “optical biopsy” of tissue 2–3 mm in depth. This sixth modality of imaging was pioneered at Lawrence Livermore National Laboratory. OCT is based on the optical scattering signatures within tissue structure. With the use of a broad spectrum bandwidth light source, high resolution images, up to 10 times the resolution of x-ray, can detect important tissue interfaces within the periodontal sulcus and its' relationship to the attachment apparatus of the tooth. Multiple cross-sectional ...
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    11. Geometric Deformable Model Driven by CoCRFs: Application to Optical Coherence Tomography

      We present a geometric deformable model driven by dynamically updated probability fields. The shape is defined with the signed distance function, and the internal (smoothness) energy consists of a C 1 continuity constraint, a shape prior, and a term that forces the zero-level of the shape distance function towards a connected form. The image probability fields are estimated by our collaborative Conditional Random Field (CoCRF), which is updated during the evolution in an active learning manner: it infers class posteriors in pixels or regions with feature ambiguities by assessing the joint appearance of neighboring sites and using the classification confidence ...
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    12. Towards Multi-Directional OCT for Speckle Noise Reduction

      Multi-directional optical coherence tomography (MD-OCT) applies and extends the concept of angular compounding for speckle noise reduction to the area of OCT imaging. OCT images are acquired from a wide range of angles of view. Averaging of the rotated images therefore requires compensation of the parallax which is achieved by simple image registration for image reconstruction. Test measurements of a sample structure in a low and highly scattering environment show that the method improves the signal-to-noise ratio by a factor of 4 and hence reduces speckle noise significantly. Experimental results also show that the proposed averaging increases the performance of ...
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    13. Multifocal VEP and OCT in optic neuritis: a topographical study of the structure–function relationship

      Abstract Purpose To investigate topographical relationship between amplitude of multifocal visual evoked potentials (mfVEP) and retinal nerve fibre layer (RNFL) thickness following acute optic neuritis (ON). Patients and Methods Fifty patients with a clinical diagnosis of acute unilateral ON between 6 and 36 months prior to the study and 25 age-matched controls underwent mfVEP testing (Accumap V 2.1, ObjectiVision Pty Ltd, Sydney, Australia) and OCT imaging (fast RNFL protocol, Stratus™, software version 3.0, Carl Zeiss Meditec, Inc., Dublin, CA). RNFL thickness and mfVEP amplitude were measured for upper, temporal and lower retinal sectors and corresponding areas of the ...
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    14. Anterior segment optical coherence tomography in eye injuries

      Background To evaluate the usefulness of anterior segment optical coherence tomography (AS OCT) for initial diagnosis and for monitoring treatment results in eye injury cases. Methods We examined 38 eyes of 34 patients with different types of ocular injuries: penetrating injury (eight eyes), perforating injury (two eyes), intraocular foreign body (four eyes), ocular burn (nine eyes), contusion (13 eyes), and lamellar laceration (two eyes). The mean age of the patients was 33.8 years. AS OCT examination was performed at the initial visit, directly after injury, and repeated as treatment progressed. Both anterior chamber components and corneal pachymetry were evaluated ...
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    15. Evolution of lamellar macular hole studied by optical coherence tomography

      Abstract Purpose  To study the natural course of lamellar macular hole (LMH) as examined by optical coherence tomography (OCT) in a noncomparative observational case series. Methods  Forty-one eyes of 41 patients with LMH were included in this analysis. Baseline and final OCT findings related to LMH diameter, foveal thickness and visual acuity (VA) were collected and compared. Mean follow-up was 37.1 months. Main outcome measures were best-corrected visual acuity (BCVA), diameter of the LMH opening, foveal thickness, epiretinal membrane (ERM), posterior vitreous detachment (PVD) and vitreoretinal traction. Results  The diameter of the LMH increased by an average of 13 ...
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    16. Update: histopathology-based definition of gastroesophageal reflux disease and Barrett's esophagus

      Summary BACKGROUND: Gastroesophageal reflux disease (GERD) is associated with columnar lined esophagus (CLE) and Barrett's esophagus (BE), which may progress towards esophageal adenocarcinoma. Currently a mixture of symptoms, endoscopic and histopathologic criteria and results obtained from esophageal function tests define GERD. We searched for a histopathology-based definition of GERD. METHODS: Review on GERD-histopathology. RESULTS: Multilevel biopsies and the novel Paull-Chandrasoma histopathology-classification of CLE define those with reflux and risk for development of esophageal adenocarcinoma (those with Barrett's esophagus and dysplasia) and list three abnormal nondysplastic epithelia between squamous and gastric oxyntic mucosa: cardiac mucosa (CM), oxyntocardiac mucosa (OCM ...
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    17. Dynamic variation of hemodynamic shear stress on the walls of developing chick hearts: computational models of the heart outflow tract

      Abstract  Heart morphogenesis and growth are influenced by hemodynamic forces (wall shear stress and blood pressure) acting on the walls of the heart. Mechanisms by which hemodynamic forces affect heart development are not well understood, in part because of difficulties involved in measuring these forces in vivo. In this paper, we show how wall shear stress in the heart outflow tract (OFT) of chick embryos at an early developmental stage (HH18) are affected by changes in the geometry and motion of the OFT wall. In particular, we were interested in the effects of cardiac cushions, which are protrusions of the ...
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    18. Optical Coherence Tomography with Applications in Cancer Imaging

      Optical coherence tomography (OCT) is a rapidly emerging optical imaging technique for a wide range of biological, medical, and material investigations [1, 2]. OCT was initially developed in the early 1990s, and has provided researchers with a novel means by which biological specimens and nonbiological samples can be visualized. A primary advantage of OCT is the ability to image tissue microstructure in situ at micron-scale image resolution, without the need for excision of a specimen for tissue processing. The optical ranging in OCT is analogous to ultrasound B-mode imaging, except that OCT uses low-coherence light rather than high-frequency sound. Cross-sectional ...
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    19. Advanced Photodynamic Therapy

      Photodynamic therapy (PDT) is the use of drugs (photosensitizers) that are activated by visible or near infrared light to produce specific biological effects in cells or tissues [1]. The basic steps in a PDT treatment are application of the photosensitizer (systemically or topically), a time interval to allow for photosensitizer accumulation in the target diseased tissue or cells, and illumination of the target area or volume with light of an appropriate wavelength to activate the sensitizer. PDT is a highly multidisciplinary topic, involving optical biophysics and bioengineering, synthetic chemistry, pharmacology, photophysics and photochemistry, photobiology, and different clinical specialties. The main ...
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    20. Endoscopic Detection of Esophageal Neoplasia (Book Chapter)

      Endoscopic Detection of Esophageal Neoplasia (Book Chapter)

      Book Chapter: Endoscopic visualization of the esophagus has been practiced since the 19th century; the first illuminated views were obtained by Mikulicz in 1880 (1). Esophagogastroduodenoscopy (EGD) or “upper endoscopy” is one of the most frequently performed semi-invasive procedures, currently accounting for approx 25% of all endoscopies conducted annually. Use of endoscopy to detect esophageal dysplasia in the United States is primarily limited to evaluation of Barrett’s esophagus (BE), an eponym describing metaplastic replacement of normal squamous mucosa of the esophagus with a columnar epithelium resembling that found in the small intestine (Fig. 1) (2). BE is the major ...

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    21. The risk of drug-eluting stent thrombosis with noncardiac surgery

      Abstract Patients in whom any kind of stent, particularly a drug-eluting stent (DES), was recently implanted are at risk for stent thrombosis when they undergo noncardiac surgery, even months or years after their implantation. The risk of DES thrombosis is likely decreased by delaying noncardiac surgery for as long as possible and continuing dual or at least single antiplatelet therapy in the perioperative period. Preoperative identification and close monitoring of patients with DES may allow prevention and prompt detection and treatment of this catastrophic complication.
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