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    1. Ultrahigh-Resolution Optical Coherence Elastography Images Cellular-Scale Stiffness of Mouse Aorta

      Ultrahigh-Resolution Optical Coherence Elastography Images Cellular-Scale Stiffness of Mouse Aorta

      Cellular-scale imaging of the mechanical properties of tissue has helped to reveal the origins of disease; however, cellular-scale resolution is not readily achievable in intact tissue volumes. Here, we demonstrate volumetric imaging of Young’s modulus using ultrahigh-resolution optical coherence elastography, and apply it to characterizing the stiffness of mouse aortas. We achieve isotropic resolution of better than 15 μ m over a 1-mm lateral field of view through the entire depth of an intact aortic wall. We employ a method of quasi-static compression elastography that measures volumetric axial strain and uses a compliant, transparent layer to measure surface axial stress ...

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    2. Broadband supercontinuum generation spanning 1.5–13 μm in Ge11.5As24Se64.5 based chalcogenide glass step index optical fiber

      Broadband supercontinuum generation spanning 1.5–13 μm in Ge11.5As24Se64.5 based chalcogenide glass step index optical fiber

      We have reported a design of a step index optical fiber in Ge 11.5 As 24 Se 64.5 chalcogenide glass. The proposed design of optical fiber is analyzed using full vectorial finite element method. The structure offers a high nonlinear coefficient of 1431 W −1  km −1 . Due to this high nonlinearity of the optical fiber a supercontinuum spectrum ranging from 1.5–13 μm is generated in only 10 mm long fiber by applying 50 fs laser secant pulses of 4000 W peak power at the pump wavelength of 3.1 μm. The use of femtosecond pulse ...

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    3. Coronary dissection or a recanalized thrombus? Optical coherence tomography has the answer

      Coronary dissection or a recanalized thrombus? Optical coherence tomography has the answer

      Intra-luminal coronary haziness during coronary angiography can be secondary to ulcerated plaque, spontaneous coronary dissection or a thrombus. During percutaneous coronary intervention, management may differ depending upon the etiology of haziness. Intravascular ultrasound and optical coherence tomography have greatly enhanced the differentiation of such intra-luminal haziness. We hereby report two cases of intra-luminal coronary haziness secondary to suspected spontaneous coronary artery dissection, which turned out to be recanalized thrombus on optical coherence tomography imaging.

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    4. Plaque Rupture in Coronary Atherosclerosis Is Associated With Increased Plaque Structural Stress

      Plaque Rupture in Coronary Atherosclerosis Is Associated With Increased Plaque Structural Stress

      Objectives The aim of this study was to identify the determinants of plaque structural stress (PSS) and the relationship between PSS and plaques with rupture. Background Plaque rupture is the most common cause of myocardial infarction , occurring particularly in higher risk lesions such as fibroatheromas. However, prospective intravascular ultrasound–virtual histology studies indicate that <10% higher risk plaques cause clinical events over 3 years, indicating that other factors also determine plaque rupture. Plaque rupture occurs when PSS exceeds its mechanical strength; however, the determinants of PSS and its association with plaques with proven rupture are not known. Methods We analyzed ...

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    5. Tomographic Biomarkers Predicting Progression to Fibrosis in Treated Neovascular Age-Related Macular Degeneration: A Multimodal Imaging Study

      Tomographic Biomarkers Predicting Progression to Fibrosis in Treated Neovascular Age-Related Macular Degeneration: A Multimodal Imaging Study

      Purpose To describe the photoreceptor–retinal pigment epithelium (RPE) interface changes and to analyze the relationships between these features and hyperreflective material (HRM) with scarring and atrophy at the macula of patients with neovascular age-related macular degeneration (nAMD). Design Retrospective single-center observational study. Participants A total of 150 eyes from 144 patients with naive nAMD were included. Methods All patients had OCT (HRA-OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany) at baseline and at 1, 3, 6, and 12 months. Macular scar and macular atrophy (MA) were determined on multimodal imaging, including color fundus (CF) and near-infrared imaging at baseline and month ...

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    6. Optical Coherence Tomography: A Novel Imaging Method for Post-lumpectomy Breast Margin Assessment—A Multi-reader Study

      Optical Coherence Tomography: A Novel Imaging Method for Post-lumpectomy Breast Margin Assessment—A Multi-reader Study

      Rationale and Objectives This study aimed to assess whether different breast cancer subspecialty physicians can be trained to distinguish non-suspicious from suspicious areas of post-lumpectomy specimen margin in patients with breast cancer using optical coherence tomography (OCT) images (a near-infrared based imaging technique) with final histology as the reference standard. Materials and Methods This institutional review board-exempt, Health Insurance Portability and Accountability Act-compliant study was performed on 63 surgically excised breast specimens from 35 female patients, creating a 90-case atlas containing both non-suspicious and suspicious areas for cancer. OCT images of the specimens were performed, providing 6.5–15 µm ...

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    7. Evaluating the effects of organic matter bioavailability on nanofiltration membrane using real-time monitoring

      Evaluating the effects of organic matter bioavailability on nanofiltration membrane using real-time monitoring

      We studied the influence of bioavailability of organic matter on membrane fouling layer development by comparing the filtration of two feed waters (wetland water and graywater). Dissolved organic carbon (DOC) concentration, size exclusion chromatography (SEC), and fluorescence excitation-emission matrix (FEEM) were used to characterize the bioavailability of organic matter in these water samples during the nanofiltration process. The wetland sample contained a high proportion of humic acid- and fulvic acid-like matter with low bioavailability, whereas the graywater sample comprised substantial amounts of aromatic proteins and microbial byproduct-like matter with high bioavailability. In addition, the molecular size distribution revealed that the ...

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    8. Comparison of optical coherence tomography findings and visual field changes in patients with primary open-angle glaucoma and amyotrophic lateral sclerosis

      Comparison of optical coherence tomography findings and visual field changes in patients with primary open-angle glaucoma and amyotrophic lateral sclerosis

      Recent studies revealing genetic connection of primary open angle glaucoma (POAG) and amyotrophic lateral sclerosis (ALS) have received particular attention. Exploring the evidence for common pathogenesis of these two progressive neurological disorders may assist in understanding the mechanism and searching for new treatment. Retinal nerve fiber layer (RNFL) defect and corresponding visual field (VF) impairment are well known neuropathy signs in glaucoma. In our study, thickness of certain retinal layer in ALS patients was analyzed to detect ganglion cell’s soma and axon, and for first time visual field was examined for ALS. The correlation of retinal involvement and ALS ...

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    9. Qualitative and quantitative assessment of cartilage degeneration using full-field optical coherence tomography ex vivo

      Qualitative and quantitative assessment of cartilage degeneration using full-field optical coherence tomography ex vivo

      Objective The purpose of this study was to investigate the ability of full-field optical coherence tomography (FFOCT) to qualitatively and quantitatively evaluate cartilage degeneration using the qualitative evaluation of histology sections as the reference. Design 33 human knee cartilage samples of variable degeneration were included in the study. A closely matching histology and FFOCT image was acquired for each sample. The cartilage degeneration was qualitatively evaluated by assigning a grade to each histology and FFOCT image. The relevance of the performed grading was assessed by calculating the intra- and inter-observer reproducibility and calculating the concordance between the histology and FFOCT ...

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    10. The application of optical coherence tomography angiography in retinal diseases

      The application of optical coherence tomography angiography in retinal diseases

      Optical coherence tomography angiography (OCTA) is a new, noninvasive imaging technique that generates real-time volumetric data on chorioretinal vasculature and its flow pattern. With the advent of high-speed optical coherence tomography, established en face chorioretinal segmentation, and efficient algorithms, OCTA generates images that resemble an angiogram. The principle of OCTA involves determining the change in backscattering between consecutive B-scans and then attributing the differences to the flow of erythrocytes through retinal blood vessels . OCTA has shown promise in the evaluation of common ophthalmologic diseases such as diabetic retinopathy , age-related macular degeneration , and retinal vascular occlusions . It quantifies vascular compromise reflecting ...

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    11. Optical coherence tomography in diagnosis and monitoring multiple sclerosis

      Optical coherence tomography in diagnosis and monitoring multiple sclerosis

      This paper presents application of optical coherence tomography (OCT) for diagnosis and monitoring of multiple sclerosis (MS). The peripapillary retinal nerve fibre layer thinning and the reduced total macular volume analysis are shown. With the course of the MS, the severity of these abnormalities increases which reflects the progressive degeneration of retinal ganglion cells and nerve fibres. The OCT parameters are sensitive, non-invasive indicators useful in assessing the progression of inflammation and neurodegeneration in MS.

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    12. Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy

      Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy

      Cell mechanical behaviour is increasingly recognised as a central biophysical parameter in cancer and stem cell research, and methods of investigating their mechanical behaviour are therefore needed. We have developed a novel qualitative method based on quantitative phase imaging which is capable of investigating cell mechanical behaviour in real-time at cellular resolution using optical coherence phase microscopy (OCPM), and stimulating the cells non-invasively using hydrostatic pressure. The method was exemplified to distinguish between cells with distinct mechanical properties, and transient change induced by Cytochalasin D. We showed the potential of quantitative phase imaging to detect nanoscale intracellular displacement induced by ...

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    13. Clinical study of optical coherence tomography in the diagnosis of peripheral pulmonary artery thrombus

      Clinical study of optical coherence tomography in the diagnosis of peripheral pulmonary artery thrombus

      Background Peripheral pulmonary artery thrombus (PPT) is common in the clinic. However, due to the lack of an ideal diagnostic tool, PPT cannot be quickly diagnosed and effectively treated at present. Optical coherence tomography (OCT) is a new intravascular imaging technique that is characterized by high image resolution. This technique is suitable for small vessel imaging and has the ability to distinguish red and white thrombi. Objective This study aimed to evaluate the value of OCT in the diagnosis of PPT and in identifying the nature of thrombi by comparing the difference in sensitivity between OCT and selective pulmonary angiography ...

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      Mentions: Wei Wang
    14. Relationship between optical coherence tomography-derived morphological criteria and functional relevance as determined by fractional flow reserve

      Relationship between optical coherence tomography-derived morphological criteria and functional relevance as determined by fractional flow reserve

      Background Although several previous studies have indicated that optical coherence tomography (OCT)-derived minimal lumen area (MLA) correlates with fractional flow reserve (FFR) severity, other morphologic criteria for functionally significant coronary stenosis assessed by FFR have not been fully elucidated. This study aimed to identify OCT-based morphological predictors of physiologically significant ischemia assessed by FFR in angiographically intermediate coronary lesions. Methods We investigated 194 de novo intermediate coronary lesions in 178 patients with stable angina pectoris who underwent OCT imaging and FFR measurement. The lesions were divided into two groups according to an FFR threshold: ischemia group, FFR <0.75 ...

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    15. Stent thrombosis: what's up in 2017?

      Stent thrombosis: what's up in 2017?

      Stent thrombosis (ST) is still a dreadful and threatening complication of percutaneous coronary intervention (PCI) with a high risk of morbi-mortality. Nevertheless, it becomes exceptional (0.6% at 1 year and 0.15%/year later) thanks to improvement of stents and use of new P2Y12 inhibitors. Endo-coronary imaging and especially Optical Coherence Tomography (OCT) change radically its understanding with revealing quiet systematic morphologic endoluminal abnormalities (97% of the cases). OCT becomes an essential tool in practice (ESC recommendation class IIa) and allows a therapeutic strategy optimization. Its prevention is based on mechanical causes correction and a personalized adaptation of anti-platelet ...

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    16. Two-harmonic complex spectral-domain optical coherence tomography using achromatic sinusoidal phase modulation

      Two-harmonic complex spectral-domain optical coherence tomography using achromatic sinusoidal phase modulation

      We resolve the complex conjugate ambiguity in spectral-domain optical coherence tomography (SD-OCT) by using achromatic two-harmonic method. Unlike previous researches, the optical phase of the fiber interferometer is modulated by an achromatic phase shifter based on an optical delay line. The achromatic phase modulation leads to a wavelength-independent scaling coefficient for the two harmonics. Dividing the mean absolute value of the first harmonic by that of the second harmonic in a B-scan interferogram directly gives the scaling coefficient. It greatly simplifies the determination of the magnitude ratio between the two harmonics without the need of third harmonic and cumbersome iterative ...

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    17. Three-year follow-up optical coherence tomography of under-expanded drug-eluting stent in-stent restenosis treated with ABSORB bioresorbable vascular scaffold following ultra-high pressure pre-dilatation

      Three-year follow-up optical coherence tomography of under-expanded drug-eluting stent in-stent restenosis treated with ABSORB bioresorbable vascular scaffold following ultra-high pressure pre-dilatation

      The management of in-stent restenosis continues to be a common challenge in modern interventional cardiology . Drug-eluting stents have emerged to be an effective treatment following bare-metal stent in-stent restenosis as compared with drug-coated balloon angioplasty and repeat bare-metal stenting . The addition of another metallic layer is however undesirable and may limit further treatment options. In the last few years, everolimus-eluting bioresorbable vascular scaffolds have become available in treating native coronary artery disease with complete hydrolysis into water and carbon dioxide within 3–5 years. To exploit this property, we successfully used it to manage a case of drug-eluting stent in-stent ...

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    18. Growth of quantum three-dimensional structure of InGaAs emitting at ~1 µm applicable for a broadband near-infrared light source

      Growth of quantum three-dimensional structure of InGaAs emitting at ~1 µm applicable for a broadband near-infrared light source

      We obtained a high-intensity and broadband emission centered at ~1 µm from InGaAs quantum three-dimensional (3D) structures grown on a GaAs substrate using molecular beam epitaxy. An InGaAs thin layer grown on GaAs with a thickness close to the critical layer thickness is normally affected by strain as a result of the lattice mismatch and introduced misfit dislocations. However, under certain growth conditions for the In concentration and growth temperature, the growth mode of the InGaAs layer can be transformed from two-dimensional to 3D growth. We found the optimal conditions to obtain a broadband emission from 3D structures with a ...

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    19. Multiple Mechanisms in 1 In-Stent Restenosis Assessed by Optical Coherence Tomography

      Multiple Mechanisms in 1 In-Stent Restenosis Assessed by Optical Coherence Tomography

      A 65-year-old male patient was admitted due to unstable angina . The patient had received percutaneous coronary intervention with 2 overlapping Taxus paclitaxel-eluting stents (Boston Scientific, Natick, Massachusetts) (3.5 × 32 mm and 3.0 × 32 mm) for his left anterior descending coronary artery long lesion 7 years ago. Coronary angiography showed left anterior descending coronary artery total occlusion since the previous first stent ( Figure 1A ). After wiring and balloon pre-dilatation, we opened the lesion ( Figure 1B ) and used optical coherence tomography (OCT) (St. Jude, Westford, Massachusetts) to check the causes of in-stent restenosis (ISR) ( Figure 1C ). Three coexisting putative causes ...

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    20. Detection of early changes in the coronary artery microstructure after heart transplantation: A prospective optical coherence tomography study

      Detection of early changes in the coronary artery microstructure after heart transplantation: A prospective optical coherence tomography study

      Objectives To describe and characterize changes in the coronary artery microstructure during the first year following heart transplantation (HTx) by serial optical coherence tomography (OCT) scans. Background OCT enables in-vivo cardiac allograft vasculopathy (CAV) microstructure characterization. Early coronary artery microstructure changes after HTx may provide important mechanistic information regarding CAV development. Methods Twenty-six patients were enrolled at routine baseline coronary angiography 3 months after HTx. Coronary OCT scans were performed in all three major vessels at baseline and were repeated 12 months after HTx. We contoured the vessel layers for absolute and relative measurements. Lipid plaques, calcified plaques, layered fibrotic ...

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    21. Analyzing external and internal membrane fouling by oil emulsions via 3D optical coherence tomography

      Analyzing external and internal membrane fouling by oil emulsions via 3D optical coherence tomography

      Membrane-based filtration is an emerging technique for processing oily wastewater. Improving the efficiency of oil-water separation via membranes entails novel techniques for studying the complex interactions between the oil droplets and membrane underlying fouling. This paper presents the first study that applies optical coherence tomography (OCT) to the characterization of membrane fouling by oil emulsions. A series of dead-end filtration experiments was performed to characterize the rejection of oil droplets (~ 10 µm; hexadecane) by the membrane structure (0.45 µm PVDF) via three-dimensional (3D) OCT scanning in real time. The experimental results were compared with the control experiments with ~ 10 ...

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