1. 1-24 of 327 1 2 3 4 ... 12 13 14 »
    1. Bioresorbable vascular scaffold overlap evaluation with optical coherence tomography after implantation with or without enhanced stent visualization system (WOLFIE study): a two-centre prospective comparison

      Bioresorbable vascular scaffold overlap evaluation with optical coherence tomography after implantation with or without enhanced stent visualization system (WOLFIE study): a two-centre prospective comparison

      To assess if enhanced stent visualization (ESV)-guided implantation of overlapping bioresorbable vascular scaffold (BVS) is superior to angiography alone-guided implantation in the reduction of overlap length. WOLFIE is a two-centre prospective open study enrolling 30 patients treated with implantation of at least two overlapping BVS. In the first centre (London), BVS implantation was guided by conventional angiography, while in the second centre (Ferrara), an ESV system was systematically employed. The primary endpoint of the study was overlap length. Secondary endpoints were: stacked struts number, area, thickness, and amount of clusters. In the ESV-guided group, overlap length was significantly lower ...

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    2. GaAs-Based Superluminescent Light-Emitting Diodes with 290-nm Emission Bandwidth by Using Hybrid Quantum Well/Quantum Dot Structures

      GaAs-Based Superluminescent Light-Emitting Diodes with 290-nm Emission Bandwidth by Using Hybrid Quantum Well/Quantum Dot Structures

      A high-performance superluminescent light-emitting diode (SLD) based upon a hybrid quantum well (QW)/quantum dot (QD) active element is reported and is assessed with regard to the resolution obtainable in an optical coherence tomography system. We report on the appearance of strong emission from higher order optical transition from the QW in a hybrid QW/QD structure. This additional emission broadening method contributes significantly to obtaining a 3-dB linewidth of 290 nm centered at 1200 nm, with 2.4 mW at room temperature.

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    3. Measurement of early changes in anterior chamber morphology after cataract extraction measured by anterior segment optical coherence tomography

      Measurement of early changes in anterior chamber morphology after cataract extraction measured by anterior segment optical coherence tomography

      Objective To evaluate the serial changes in anterior chamber depth (ACD) and angle parameters early after cataract surgery using anterior segment optical coherence tomography (ASOCT). Methods This was a retrospective chart review, case–control study; 150 eyes of 106 patients who underwent cataract surgery. Based on ACD and angle findings, the eyes were classified into two groups, open-angle eyes (87 eyes) and narrow-angle eyes (63 eyes). ASOCT was used to measure ACD and angle parameters (angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle (TIA [ 1 ]). Serial changes in each group were measured before and ...

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    4. Spectral-domain optical coherence tomography of macula in myopia

      Spectral-domain optical coherence tomography of macula in myopia

      The aim of this study is to determine the associations between regional macular thickness and gender, age, axial length, and degree of myopia in young and middle-aged healthy myopic eyes. One hundred and seventy-one subjects with −0.5 diopters of myopia or worse underwent prospective macular thickness measurement by Spectralis spectral-domain optical coherence tomography. Subjects’ mean age was 32.40 ± 8.25 years (range 18 to 49 years), with 45 % being male. The mean degree of myopia was −4.57 ± 3.52 diopters, with a mean axial length of 25.09 ± 1.67 mm. Multivariate regression analysis demonstrated significantly thicker ...

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    5. Retinal imaging with en face and cross-sectional optical coherence tomography delineates outer retinal changes in cancer-associated retinopathy secondary to Merkel cell carcinoma

      Retinal imaging with en face and cross-sectional optical coherence tomography delineates outer retinal changes in cancer-associated retinopathy secondary to Merkel cell carcinoma

      Background The study aims to correlate Fourier-domain optical coherence tomography (FD-OCT) with Goldmann visual field (GVF) to show the photoreceptor (PR) structure and function relationship in the first described case of cancer-associated retinopathy (CAR) from Merkel cell carcinoma. Findings A case study of a patient with CAR who was imaged with serial GVF and FD-OCT over a 2-year period was carried out. En face images were created using a custom algorithm from the volumetric Fourier-domain OCT scans at the PR level. The areas of decreased PR reflectivity on the en face images were compared with GVF obtained at the same ...

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    6. Beyond Endoscopy-Ultrasound, Optical Coherence Tomography and Confocal Laser Endomicroscopy (Book Chapter)

      Beyond Endoscopy-Ultrasound, Optical Coherence Tomography and Confocal Laser Endomicroscopy (Book Chapter)

      One of the main challenges in endoscopic diagnosis and treatment of upper urinary tract urothelial carcinoma is the complicated anatomy and the small size of the upper urinary tract, resulting in high demands on the armamentarium and expertise of the urologist. Difficulties to reach the complete collecting system could result in an incomplete visual inspection.

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    7. Quantitative precision of optical frequency domain imaging: direct comparison with frequency domain optical coherence tomography and intravascular ultrasound

      Quantitative precision of optical frequency domain imaging: direct comparison with frequency domain optical coherence tomography and intravascular ultrasound

      No systematic validation study is available with optical frequency domain imaging (OFDI), directly compared with frequency domain optical coherence tomography (FD-OCT) and intravascular ultrasound (IVUS). Controversy also remains about the impact of different stent contour tracing methods by OFDI/FD-OCT. In vitro: coronary phantom models (1.51–5.04 mm) were imaged with OFDI, FD-OCT, and IVUS, demonstrating excellent quantitative precision with a slight overestimation of mean lumen diameter (difference 0.01–0.02 mm). In vivo: corresponding 64 OFDI/IVUS images of stented coronary segments from 20 swines were analyzed. Minimum lumen area by OFDI was larger than IVUS ...

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    8. Comparison of the performance of zotarolimus- and everolimus-eluting stents by optical coherence tomography and coronary angioscopy

      Comparison of the performance of zotarolimus- and everolimus-eluting stents by optical coherence tomography and coronary angioscopy

      Overall stent performance should be characterized by geometric luminal gain acquisition, neointimal coverage of the stent struts, and stabilization of the underlying inflammatory neoatheroma. The aim of this study was to compare the performance of zotarolimus-eluting stent (ZES), everolimus-eluting stent (EES) and bare metal stent (BMS) using optical coherence tomography (OCT) and coronary angioscopy. For 36 stented coronary lesions (BMS, 12 lesions; ZES, 11 lesions; EES, 13 lesions) in 27 patients, we calculated neointimal area and uncovered stent strut rate based on OCT findings at 10 months after stent placement. The grades of neointimal coverage and yellow color, both of ...

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    9. Optical coherence tomography angiography findings of choroidal neovascularization in pseudoxanthoma elasticum

      Optical coherence tomography angiography findings of choroidal neovascularization in pseudoxanthoma elasticum

      Angioid streaks (AS) are the most common ocular manifestation in patients with pseudoxanthoma elasticum (PXE). The major cause of severe visual loss in patients with AS is choroidal neovascularization (CNV). We report the optical coherence tomography angiography (OCTA) findings of CNV in a patient with PXE and angioid streaks. A 51-year-old man with PXE presented with visual disturbance in his right eye. Best corrected visual acuity was 20/30 OD and 20/30 OS. Funduscopic examination revealed angioid streaks and type 1 NV in his right eye. Multimodal imaging including OCTA demonstrated CNV nasal to the fovea. The morphology and ...

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      Mentions: K. Bailey Freund
    10. Optical coherence tomography and pathological myopia: an update of the literature

      Optical coherence tomography and pathological myopia: an update of the literature

      The purpose of this paper is to give an updated review of the last clinical entities in pathological myopia proposed by means of new generation optical coherence tomography (OCT), including enhanced depth imaging (EDI-OCT) and swept source OCT (SS-OCT). PubMed and Google engine search were carried out using the terms “pathological myopia” associated with “coherence tomography,” “enhanced depth imaging,” and “swept source OCT.” Latest publications up to Jan 2015 about myopia-related complications, including open-angle chronic glaucoma, peripapillary retinal changes, acquired macular diseases, and choroidal neovascularization, have been reviewed. New OCT technologies have led to a greater insight in pathophysiology of ...

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    11. Abnormal traction of the vitreous detected by swept-source optical coherence tomography is related to the maculopathy associated with optic disc pits

      Abnormal traction of the vitreous detected by swept-source optical coherence tomography is related to the maculopathy associated with optic disc pits

      Background Maculopathy associated with optic disc pits (ODP), which sometimes causes severe visual loss, usually appears in late childhood or early adulthood. However, it has long been unclear how the disease begins to develop at these ages. We evaluated the relationship between vitreous structure and maculopathy associated with ODP. Methods Six patients (seven eyes) with ODP were diagnosed between July 1990 and May 2013. Fundus photographs and swept-source optical coherence tomography (SS-OCT) images were evaluated retrospectively, and the vitreous at the vitreoretinal interface was visualized by reconstructing three-dimensional SS-OCT images. Vitrectomy was performed in the eyes with maculopathy. Results Among ...

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    12. Correlation between optic disc perfusion and glaucomatous severity in patients with open-angle glaucoma: an optical coherence tomography angiography study

      Correlation between optic disc perfusion and glaucomatous severity in patients with open-angle glaucoma: an optical coherence tomography angiography study

      Purpose To explore how optic disc perfusion varies in patients with open-angle glaucoma (OAG) and how this correlates with glaucoma severity. Methods We performed a prospective and cross-sectional observational study that included 62 eyes from 62 patients with OAG, divided into three groups according to their visual field (VF) results, and 20 eyes from 20 normal control subjects. Optic disc perfusion was studied using optical coherence tomography angiography (angio-OCT), and flow index and vessel density were determined. The VF, mean deviation (MD), pattern standard deviation (PSD), retinal nerve fiber layer (RNFL) thickness, and ganglion cell complex (GCC) thickness were also ...

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    13. OCT demonstrating neoatherosclerosis as part of the continuous process of coronary artery disease

      OCT demonstrating neoatherosclerosis as part of the continuous process of coronary artery disease

      Although the advent of drug-eluting stents has reduced the rates of target vessel revascularization, there are observations of ongoing stent failure occurring very late after stent implantation and presenting as very late restenosis or as very late stent thrombosis. The de novo development of atherosclerosis within the neointimal region, called neoatherosclerosis, has been identified as one of the pathomechanisms of these observed late stent failures. The mechanisms of neoatherosclerosis development and its association with stent failure are currently the subject of intensive research. Optical coherence tomography (OCT) is an invasive imaging modality that allows us to visualize the micromorphology of ...

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    14. Experimental investigation of intravascular OCT for imaging of intracranial aneurysms

      Experimental investigation of intravascular OCT for imaging of intracranial aneurysms

      Purpose Rupture risk assessment of an intracranial aneurysm (IA) is an important factor for indication of therapy. Until today, there is no suitable objective prediction method. Conventional imaging modalities cannot assess the IA’s vessel wall. We investigated the ability of intravascular optical coherence tomography (OCT) as a new tool for the characterization and evaluation of IAs. Materials and methods An experimental setup for acquisition of geometrical aneurysm parameters was developed. Object of basic investigation was a silicone phantom with six IAs from patient data. For structural information, three circle of Willis were dissected and imaged postmortem. All image data ...

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    15. Optical coherence tomography findings in Huntington’s disease: a potential biomarker of disease progression - Online First

      Optical coherence tomography findings in Huntington’s disease: a potential biomarker of disease progression - Online First

      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 ...

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    16. Comparison of long-term in-stent vascular response between abluminal groove-filled biodegradable polymer sirolimus-eluting stent and durable polymer everolimus-eluting stent: 3-year OCT follow-up from the TARGET I trial

      Comparison of long-term in-stent vascular response between abluminal groove-filled biodegradable polymer sirolimus-eluting stent and durable polymer everolimus-eluting stent: 3-year OCT follow-up from the TARGET I trial

      The study sought to compare long-term optical coherence tomography (OCT)-based in-stent vascular response between the abluminal groove-filled biodegradable polymer sirolimus-eluting stent (SES) and the durable polymer everolimus-eluting stent (EES) in the TARGET I trial. The TARGET I trial was a prospective, multicenter, randomized clinical trial which enrolled 458 patients with single de novo lesions treated by abluminal groove-filled biodegradable polymer SES and EES. A subset of 43 patients underwent angiography and OCT examinations at 3 years. All OCT images were analyzed at 0.4 mm intervals. A similar increase in angiographic late lumen loss was observed in SES and ...

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    17. Reflection, phase and en -face sectional imaging of scattering objects using quasi-single-shot wide-field optical coherence tomography

      Reflection, phase and en -face sectional imaging of scattering objects using quasi-single-shot wide-field optical coherence tomography

      We report a quasi-single-shot wide-field optical coherence tomography system that enables to measure the reflection, phase and en - face OCT images from the same setup using the glass jig. The jig consisting of a wedge glass substrate and a glue dot is contacted to the tissue surfaces, and the data within glue dot is used to reduce the phase noise of the interference signal. The reconstructed image size of the object was 4.0 mm × 4.3 mm. The standard deviation (STD) of the phase variation was minimized by 54 % and obtained to be 0.027 rad for the poke ...

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    18. Intraoperative Assessment of Final Margins with a Handheld Optical Imaging Probe During Breast-Conserving Surgery May Reduce the Reoperation Rate: Results of a Multicenter Stud

      Intraoperative Assessment of Final Margins with a Handheld Optical Imaging Probe During Breast-Conserving Surgery May Reduce the Reoperation Rate: Results of a Multicenter Stud

      Background A multicenter, prospective, blinded study was performed to test the feasibility of using a handheld optical imaging probe for the intraoperative assessment of final surgical margins during breast-conserving surgery (BCS) and to determine the potential impact on patient outcomes. Methods Forty-six patients with early-stage breast cancer (one with bilateral disease) undergoing BCS at two study sites, the Johns Hopkins Hospital and Anne Arundel Medical Center, were enrolled in this study. During BCS, cavity-shaved margins were obtained and the final margins were examined ex vivo in the operating room with a probe incorporating optical coherence tomography (OCT) hardware and interferometric ...

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    19. Clinical utility of quantitative bright spots analysis in patients with acute coronary syndrome: an optical coherence tomography study

      Clinical utility of quantitative bright spots analysis in patients with acute coronary syndrome: an optical coherence tomography study

      To investigate the clinical significance of bright spots in coronary plaque detected by optical coherence tomography (OCT) in patients with coronary artery disease. We identified 112 patients [acute coronary syndromes (ACS): n = 50, stable angina pectoris (SAP): n = 62] who underwent OCT imaging of the culprit lesion. A novel OCT algorithm was applied to detect bright spots representing the juxtaposition of a variety of plaque components including macrophages. The density of bright spots within the most superficial 250 μm of the vessel wall was measured at the site of culprit lesion. Bright spot density in the culprit lesion was significantly ...

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    20. Stage-based frequency-modulated full-range complex Fourier-domain optical coherence tomography

      Stage-based frequency-modulated full-range complex Fourier-domain optical coherence tomography

      We propose a simple method to modulate spatial interferogram to achieve full-range complex imaging in Fourier-domain optical coherence tomography, in which a sample stage is employed which can be adjusted to introduce a constant carrier frequency into the interference signal during the B-scan by adjusting the stage angle with respect to the normal to the object under test. An additional phase, which is linearly related to the lateral position, is then induced in the A-scan. The in vivo images of human skin were generated which demonstrate that the method proposed can generate the cross-sectional image with the same quality with ...

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      Mentions: Wanrong Gao
    21. Dental optical coherence tomography: new potential diagnostic system for cracked-tooth syndrome

      Dental optical coherence tomography: new potential diagnostic system for cracked-tooth syndrome

      Purpose The aim of the present study was to determine the reliability of optical coherence tomography (OCT) in detecting cracked teeth and its relative clinical effectiveness by comparing it with other diagnostic methods including conventional visual inspection, trans-illumination, and micro-computed tomography (micro-CT). Methods The reliability of swept source OCT (SS-OCT) was verified by comparing the number of detected crack lines on 109 surfaces of 61 teeth with those detected with other conventional methods. Results One to one comparison revealed that crack lines that were invisible with naked eyes could be found in SS-OCT images. The detection ability of SS-OCT was ...

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    22. Absolute velocity measurement using three-beam spectral-domain Doppler optical coherence tomography

      Absolute velocity measurement using three-beam spectral-domain Doppler optical coherence tomography

      We report the development of a three-beam spectral-domain Doppler optical coherence tomography setup that allows single interferometer-based measurement of absolute flow velocity. The setup makes use of galvo-based phase shifting to remove complex conjugate mirror artifact and a beam displacer in the sample arm to avoid cross talk image. The results show that the developed approach allows efficient utilization of the imaging range of the spectral-domain optical coherence tomography setup for three-beam-based velocity measurement.

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    23. High Resolution Optical Coherence Tomography for Bio-Imaging

      High Resolution Optical Coherence Tomography for Bio-Imaging

      Optical coherence tomography (OCT) is a low-coherence interferometry based bio-imaging technology. It has attracted extensive research interests in recent years for its non-invasive, high-speed and high-resolution properties. Numerous schemes for improving OCT resolutions have been demonstrated in literature. This chapter gives a comprehensive review of the recent developments of spectral domain (SD)-OCT systems with either high axial-resolution or lateral resolution, and then highlights the wide applications of such high-resolution OCT systems in biomedical imaging process. The influences of high-resolution OCT systems towards translational medicine are also discussed

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