1. 1-24 of 467 1 2 3 4 ... 18 19 20 »
    1. Development of a new catheter prototype for laser thrombolysis under guidance of optical coherence tomography (OCT): validation of feasibility and efficacy in a preclinical model

      Development of a new catheter prototype for laser thrombolysis under guidance of optical coherence tomography (OCT): validation of feasibility and efficacy in a preclinical model

      In this feasibility study, a novel catheter prototype for laser thrombolysis under the guidance of optical coherence tomography (OCT) was designed and evaluated in a preclinical model. Human arteries and veins were integrated into a physiological flow model and occluded with thrombi made from the Chandler Loop. There were four experimental groups: placebo, 20 mg alteplase, laser, 20 mg alteplase + laser. The extent of thrombolysis was analyzed by weighing, OCT imaging and relative thrombus size. In the alteplase group, thrombus size decreased to 0.250 ± 0.036 g (p < 0.0001) and 14.495 ± 0.526 mm 2 (p < 0 ...

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    2. Effects of age and gender on macular thickness in healthy subjects using spectral optical coherence tomography/scanning laser ophthalmoscopy

      Effects of age and gender on macular thickness in healthy subjects using spectral optical coherence tomography/scanning laser ophthalmoscopy

      Purpose To examine healthy subjects for normal macular thickness values and determine the effects of gender and age in a Turkish population, using spectral optical coherence tomography/scanning laser ophthalmoscopy (OCT/SLO). Material and method Six hundred fourteen eyes of 307 subjects with no history of ocular diseases and normal ophthalmic examination were recruited in this cross-sectional, prospective study. The participants were divided into three groups based on age (between 20 and 29 years: group 1, between 30 and 39 years: group 2, between 40 and 49 years: group 3). All subjects were scanned with spectral OCT/SLO, performed by ...

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    3. Morphological differences between optic disc collaterals and neovascularization on optical coherence tomography angiography

      Morphological differences between optic disc collaterals and neovascularization on optical coherence tomography angiography

      Background To study morphological features of optic disc venous collaterals (OVCs) and neovascularization of optic disc (NVD) on optical coherence tomography angiography (OCTA). Methods Patients with OVCs and NVDs secondary to ischemic retinal diseases were prospectively enrolled. Multimodal imaging was performed using color fundus photography, fluorescein angiography (FA), and OCTA. Morphological evaluation of en-face structural OCT, cross-sectional and en-face OCTA was performed. Results Twenty eyes (20 patients; OVCs: n  = 10 and NVD: n  = 10) were included. OVCs appeared as small, loopy vessels distinct from surrounding peripapillary capillaries on OCTA in the radial peripapillary capillary frame. NVDs appeared as a mesh ...

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      Mentions: Vishali Gupta
    4. Optical coherence tomography findings after longitudinal ablation for an underexpanded stent in a heavily calcified lesion: a case repor

      Optical coherence tomography findings after longitudinal ablation for an underexpanded stent in a heavily calcified lesion: a case repor

      Background Heavy coronary artery calcification is responsible for stent underexpansion, which is associated with increased in-stent restenosis. Here we report a case in which optical coherence tomography (OCT) demonstrated that the metal component of an underexpanded stent previously implanted in a heavy calcified lesion had been completely removed after ablation with rotational atherectomy. Case presentation An 83-year-old man with exertional angina was referred to our hospital. Coronary angiography revealed severe stenosis in the proximal portion of the right coronary artery and left circumflex artery and chronic total occlusion (CTO) in the mid portion of the left anterior descending artery (LAD ...

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    5. Accuracy of coronary computed tomography angiography for bioresorbable scaffold luminal investigation: a comparison with optical coherence tomography

      Accuracy of coronary computed tomography angiography for bioresorbable scaffold luminal investigation: a comparison with optical coherence tomography

      To establish the accuracy of coronary computed tomography angiography (CTA) for in-scaffold quantitative evaluation with optical coherence tomography (OCT) as a reference. The translucent backbone of the bioresorbable scaffold allow us to evaluate non-invasively the coronary lumen with coronary CTA. In the ABSORB first-in-man studies, coronary CTA was shown to be feasible for quantitative luminal assessment. Nevertheless, a comparison with an intravascular modality with higher resolution has never been performed. In the ABSORB Cohort B trial, 101 patient with non-complex lesions were treated with the fully biodegradable vascular scaffold. For this analysis, all patients who underwent coronary CTA at 18 ...

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    6. Spectral Domain Optical Coherence Tomography in Macular Diseases (Textbook)

      Spectral Domain Optical Coherence Tomography in Macular Diseases (Textbook)

      Undoubtedly, optical coherence tomography has changed the approach of clinicians in their daily practice. The evolution of technology from time domain to spectral domain and swept source OCT increased the possibilities of imaging the retinal and choroidal details. Newer evaluations are now available to better understand the diseases and to fi nd new biomarkers for retinal and choroidal pathologies. From measurement to morphology could be the right description of changes occurring from time domain to spectral domain. The possibility to visualize retinal and choroidal morphology in real life and not only post-mortem allowed a better understanding not only of the ...

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    7. Different foveal schisis patterns in each retinal layer in eyes with hereditary juvenile retinoschisis evaluated by en-face optical coherence tomography

      Different foveal schisis patterns in each retinal layer in eyes with hereditary juvenile retinoschisis evaluated by en-face optical coherence tomography

      Purpose To analyze the structures of schisis in eyes with hereditary juvenile retinoschisis using en-face optical coherence tomography (OCT) imaging. Methods In this retrospective observational study, we reviewed the medical records of patients with hereditary juvenile retinoschisis who underwent comprehensive ophthalmic examinations including swept-source OCT. Results OCT images were obtained from 16 eyes of nine boys (mean age ± standard deviation, 10.6 ± 4.0 years). The horizontal OCT images at the fovea showed inner nuclear layer (INL) schisis in one eye (6.3 %), ganglion cell layer (GCL) and INL schisis in 12 eyes (75.0 %), INL and outer plexiform layer ...

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    8. Spectral-domain optical coherence tomography findings in idiopathic lamellar macular hole

      Spectral-domain optical coherence tomography findings in idiopathic lamellar macular hole

      Background To evaluate demographic, functional, and morphological parameters of idiopathic lamellar macular hole (ILMH). Methods Observational longitudinal retrospective study. Optical coherence tomography examinations and corresponding clinical charts of a series of consecutive patients affected by ILMH, between January 2010 and March 2015, from the database of the Department of Ophthalmology of Trento Hospital, Italy, have been collected and examined. Demographic and functional parameters were: age (year), gender (male/female), eye (right/left), lens status, best-corrected visual acuity (BCVA) in logarithm of the minimum angle of resolution (LogMAR). Tomographic parameters were: LMH shape pattern (intraretinal splitting LMH, IR split LMH, and ...

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    9. Dual-path handheld system for cornea and retina imaging using optical coherence tomography

      Dual-path handheld system for cornea and retina imaging using optical coherence tomography

      A dual-path handheld system is proposed for cornea and retina imaging using spectral domain optical coherence tomography. The handheld sample arm is designed to acquire two images simultaneously. Both eyes of a person can be imaged at the same time to obtain the images of the cornea of one eye and the retina of the other eye. Cornea, retina, and optic disc images are acquired with the proposed sample arm. Experimental results demonstrate the usefulness of this system for imaging of different eye segments. This system reduces the time required for imaging of the two eyes and is cost effective.

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    10. Measurements of donor endothelial keratoplasty lenticules prepared from fresh donated whole eyes by using ultrasound and optical coherence tomography

      Measurements of donor endothelial keratoplasty lenticules prepared from fresh donated whole eyes by using ultrasound and optical coherence tomography

      This study was conducted to analyze the profile and thickness of endothelial keratoplasty lenticules prepared from fresh donated whole eyes with Visante optical coherence tomography (V-OCT) compared to measurements obtained from ultrasound pachymetry (USP) at the Central Eye Bank of Iran. Microkeratome-assisted precut corneas were prepared for Descemet stripping automated endothelial keratoplasty by using standard eye bank protocol. Central posterior lenticule thickness (CPLT) on fresh whole eye, before excising corneoscleral disc and transferring to Optisol-GS, was measured by USP. V-OCT was used to measure central, paracentral, and midperipheral thicknesses of lenticules after transferring the tissue to Optisol-GS. Chi Square and ...

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    11. Disruption of bioresorbable vascular scaffold struts due to loss of radial integrity: insights from optical coherence tomography

      Disruption of bioresorbable vascular scaffold struts due to loss of radial integrity: insights from optical coherence tomography

      Strut disruption of bioresorbable vascular scaffold is a known potential concern, although uncommon when adequate lesion preparation is achieved and nominal size of the scaffold is respected. It is usually difficult to detect with angiography and/or intravascular ultrasound. Three-dimensional reconstructions of optical coherence tomography facilitates understanding of complex luminal anatomy and configuration of stent struts, providing evaluation of stent integrity immediately after deployment and therefore optimization of the complex revascularization procedure. The present article reports a case where this image modality enabled successful use of a drug-eluting stent inside a bioresorbable vascular scaffold to restore the luminal integrity, jeopardized ...

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    12. Optical coherence tomography: influence of contrast concentration on image quality and diagnostic confidence

      Optical coherence tomography: influence of contrast concentration on image quality and diagnostic confidence

      OCT requires intracoronary injection of contrast agent to remove blood from the coronary lumen during data acquisition, which is a possible limitation of this method. Aim of this study was to analyze the influence of iodine concentration on image quality and diagnostic certainty of optical coherence tomography (OCT). OCT sequences acquired using contrast agent with a reduced concentration of 150 mg iodine/ml and a standard concentration of 350 mg iodine/ml were analyzed. Cross-sectional images with a spacing of 10 mm were evaluated regarding image quality and diagnostic confidence. A total of 67 OCT sequences acquired in 24 patients ...

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    13. Human ex-vivo oral tissue imaging using spectral domain polarization sensitive optical coherence tomography

      Human ex-vivo oral tissue imaging using spectral domain polarization sensitive optical coherence tomography

      We report the use of spectral domain polarization sensitive optical coherence tomography for ex-vivo imaging of human oral mandibular tissue samples. Our results show that compared to the changes observed in the epithelium thickness and the decay constant of A-scan intensity profile, a much larger degree of change was observed in the phase retardation for tissue sites progressing from normal to the malignant state. These results suggest that monitoring of tissue retardance can help in better differentiation of normal and cancerous oral tissue sites.

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    14. Optical Coherence Tomography Angiography in Diabetes

      Optical Coherence Tomography Angiography in Diabetes

      Diabetic retinopathy is a progressive microvascular disease that leads to increased vessel permeability, retinal ischemia, and retinal neovascularization. Optical coherence tomography angiography (OCTA) is a novel angiography technique that has the capability to advance our understanding of diabetic eye disease by providing high-resolution images of retinal and choroidal microvasculature blood flow and structure. Using OCTA, the vascular changes of diabetic retinopathy including microaneurysms, retinal non-perfusion, intraretinal microvascular abnormalities, and neovascularization can be clearly visualized. OCTA offers several advantages over fluorescein angiography (FA) in that it is faster, safer, and non-invasive, allows better visualization of retinal vessels in both the superficial ...

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      Mentions: Richard B. Rosen
    15. Selective and complementary use of Optical Coherence Tomography and Fluorescein Angiography in retinal practice

      Selective and complementary use of Optical Coherence Tomography and Fluorescein Angiography in retinal practice

      The current field of posterior pole and retinal imaging of the human eye has expanded into detailed analyses of the macula, retinal periphery, individual retinal layers, vitreoretinal interface, imaging of the choroid and the optic nerve head. The challenge in retinal imaging is the enduring pursuit of deeper penetration into tissues, increased resolution to the cellular level, and interpretation of observations. How much deeper can we go and with what resolution and reproducibility? These are fundamental questions for experts in search of novel imaging modalities. New discoveries may resolve existing controversies, but inevitably stimulate new questions. Emerging technologies in retinal ...

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      Mentions: Igor Kozak
    16. Axial Alignment for Anterior Segment Swept Source Optical Coherence Tomography via Robust Low-Rank Tensor Recovery

      Axial Alignment for Anterior Segment Swept Source Optical Coherence Tomography via Robust Low-Rank Tensor Recovery

      We present a one-step approach based on low-rank tensor recovery for axial alignment in 360-degree anterior chamber optical coherence tomography. Achieving translational alignment and rotation correction of cross-sections simultaneously, this technique obtains a better anterior segment topographical representation and improves quantitative measurement accuracy and reproducibility of disease related parameters. Through its use of global information, the proposed method is more robust compared to using only individual or paired slices, and less sensitive to noise and motion artifacts. In angle closure analysis on 30 patient eyes, the preliminary results indicate that the proposed axial alignment method can not only facilitate manual ...

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    17. Serial optical coherence tomography angiography for corneal vascularization

      Serial optical coherence tomography angiography for corneal vascularization

      Purpose Recently, optical coherence tomography angiography (OCTA) has been used to successfully delineate vessels within the retina. This current study aims to assess corneal vascularization secondary to herpetic keratitis pre- and post-treatment using serial OCTA imaging adapted for the anterior segment. Methods All eyes were scanned using the split-spectrum amplitude decorrelation angiography (SSADA) algorithm on the AngioVue OCTA system (Optovue Inc. Fremont, CA, USA) with an anterior segment lens adapter. Multiple scans in the regions of interest (ROI) before and after treatment were analysed to assess change in corneal vascularization in response to each treatment modality. Results We analyzed a ...

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      Mentions: Optovue
    18. Combined optical coherence tomography morphologic and fractional flow reserve hemodynamic assessment of non- culprit lesions to better predict adverse event outcomes in diabetes mellitus patients: COMBINE (OCT–FFR) prospective study. Rationale and design

      Combined optical coherence tomography morphologic and fractional flow reserve hemodynamic assessment of non- culprit lesions to better predict adverse event outcomes in diabetes mellitus patients: COMBINE (OCT–FFR) prospective study. Rationale and design

      Background Fractional flow reserve (FFR) is a widely used tool for the identification of ischaemia-generating stenoses and to guide decisions on coronary revascularisation. However, the safety of FFR-based decisions in high-risk subsets, such as patients with Diabetes Mellitus (DM) or vulnerable stenoses presenting thin-cap fibro-atheroma (TCFA), is unknown. This study will examine the impact of optical coherence tomography (OCT) plaque morphological assessment and the identification of TCFA, in combination with FFR to better predict clinical outcomes in DM patients. Methods COMBINE (OCT–FFR) is a prospective, multi-centre study investigating the natural history of DM patients with ≥1 angiographically intermediate target ...

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      Mentions: Fernando Alfonso
    19. Intraoperative Optical Coherence Tomography in Lamellar Keratoplasties: Indications and Outcomes

      Intraoperative Optical Coherence Tomography in Lamellar Keratoplasties: Indications and Outcomes

      Purpose of Review Lamellar keratoplasties are evolving techniques to selectively replace diseased or opacified layers of the cornea. In recent years, the popularity of lamellar keratoplasties, especially Descemet membrane endothelial keratoplasty, Descemet stripping-automated endothelial keratoplasty and deep anterior lamellar keratoplasty, increased dramatically, since lamellar surgeries reduce intra- and postoperative complications and achieve faster visual recovery. Nonetheless, the surgical procedures are delicate. Recent Findings Novel imaging techniques, as intraoperative optical coherence tomography (OCT), may substantially help standardize these procedures to even further reduce intra- and postoperative complications and potentially improve outcome. Summary The present review summarizes the current literature regarding the ...

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    20. Morphological analysis of the growth stages of in-vivo mouse hair follicles by using optical coherence tomography

      Morphological analysis of the growth stages of in-vivo mouse hair follicles by using optical coherence tomography

      Swept-source optical coherence tomography (SS-OCT), a bio-photonic imaging modality, was used to demonstrate an initial feasibility experiment for detecting morphological variations of in-vivo mouse hair follicles for the anagen and the telogen growth stages. Two C57BL/6 adult male mice, one undergoing the anagen stage and the other undergoing the telogen stage of the hair follicle growth cycle, were selected for the experiment. The OCT cross-sectional images of mice skin were acquired in-vivo within an interval of 15 days, and the observed morphological changes were analyzed. The micro-structural features of mice skin on the 15th experimental day were further compared ...

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      Mentions: Jeehyun Kim
    21. An Evaluation of Computational Imaging Techniques for Heterogeneous Inverse Scattering

      An Evaluation of Computational Imaging Techniques for Heterogeneous Inverse Scattering

      Inferring internal scattering parameters for general, heterogeneous materials, remains a challenging inverse problem. Its difficulty arises from the complex way in which scattering materials interact with light, as well as the very high dimensionality of the material space implied by heterogeneity. The recent emergence of diverse computational imaging techniques, together with the widespread availability of computing power, present a renewed opportunity for tackling this problem. We take first steps in this direction, by deriving theoretical results, developing an algorithmic framework, and performing quantitative evaluations for the problem of heterogeneous inverse scattering from simulated measurements of different computational imaging configurations.

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