1. 1-24 of 445 1 2 3 4 ... 17 18 19 »
    1. 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
    2. 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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    3. Progression of erosive lesions after Nd:YAG laser and fluoride using optical coherence tomography

      Progression of erosive lesions after Nd:YAG laser and fluoride using optical coherence tomography

      This study aimed to use optical coherence tomography (OCT) to assess the progression of erosive lesions after irradiation with Nd:YAG laser and application of topical fluoride. One-hundred and twenty dentin samples (4 × 4 × 2 mm) obtained from bovine incisors were used. Samples were protected with acid-resistant nail varnish, with exception of a central circular area 2 mm in diameter. All samples were submitted to erosive cycles with citric acid solution 0.05 M (citric acid monohydrate—C6H8O7·H2O); M = 210.14 g/mol) pH 2.3, at room temperature, for 20 min, 2×/day, throughout 20 days. After 10 ...

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    4. A Mosaicking Approach for In Vivo Thickness Mapping of the Human Tympanic Membrane Using Low Coherence Interferometry

      A Mosaicking Approach for In Vivo Thickness Mapping of the Human Tympanic Membrane Using Low Coherence Interferometry

      The thickness of the human tympanic membrane (TM) is known to vary considerably across different regions of the TM. Quantitative determination of the thickness distribution and mapping of the TM is of significant importance in hearing research, particularly in mathematical modeling of middle-ear dynamics. Change in TM thickness is also associated with several middle-ear pathologies. Determination of the TM thickness distribution could therefore also enable a more comprehensive diagnosis of various otologic diseases. Despite its importance, very limited data on human TM thickness distribution, obtained almost exclusively from ex vivo samples, are available in the literature. In this study, the ...

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    5. Full-thickness choroidal thinning as a feature of Fuchs Uveitis Syndrome: quantitative evaluation of the choroid by Enhanced Depth Imaging Optical Coherence Tomography in a cohort of consecutive patients

      Full-thickness choroidal thinning as a feature of Fuchs Uveitis Syndrome: quantitative evaluation of the choroid by Enhanced Depth Imaging Optical Coherence Tomography in a cohort of consecutive patients

      Purpose To perform a quantitative analysis of choroidal thickness in patients with Fuchs Uveitis Syndrome (FUS) using enhanced depth imaging optical coherence tomography (EDI-OCT). Methods All patients underwent comprehensive ophthalmic examination, including best-corrected visual acuity, slit-lamp biomicroscopy, applanation tonometry, axial length measurements with a swept-source biometer (IOLMaster 700, Carl Zeiss Medic AG, Jena, Germany) and macular 30° linear EDI- B-scan SD-OCT section (Spectralis HRAII+OCT, Heidelberg Engineering, Heidelberg, Germany) in both eyes. Analysis of choroidal thickness was performed at three different locations: subfoveally, 750 μm nasally, and 750 μm temporally to the fovea. Patients having received any surgery or intravitreal ...

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    6. Galvanometer Laser Scanning: Custom-Made Input Signals for Maximum Duty Cycles in High-End Imaging Applications

      Galvanometer Laser Scanning: Custom-Made Input Signals for Maximum Duty Cycles in High-End Imaging Applications

      The paper presents some of the contributions achieved in the study of galvanometer-based scanners (GSs) utilized for high-end applications. The optomechatronic aspects of this most used type of laser scanners are presented, in relationship with the high requirements of biomedical imaging, for example. The use of GSs with common input signals, such as triangular, sawtooth, and sinusoidal for domains like Optical Coherence Tomography (OCT) for example are discussed—as studied in several researches. Custom-made input signals for GSs are considered in this presentation, and the analysis made on their effect on the of GS duty cycle (i.e., on the ...

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    7. Optical coherence tomography attenuation imaging for lipid core detection: an ex-vivo validation study

      Optical coherence tomography attenuation imaging for lipid core detection: an ex-vivo validation study

      Lipid-core atherosclerotic plaques are associated with disease progression, procedural complications, and cardiac events. Coronary plaque lipid can be quantified in optical coherence tomography (OCT) pullbacks by measurement of lipid arcs and lipid lengths; parameters frequently used in clinical research, but labor intensive and subjective to analyse. In this study, we investigated the ability of quantitative attenuation, derived from intravascular OCT, to detect plaque lipid. Lipid cores are associated with a high attenuation coefficient. We compared the index of plaque attenuation (IPA), a local quantitative measure of attenuation, to the manually measured lipid score (arc and length) on OCT images, and ...

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    8. Deep inside Multifocal Choroiditis: an Optical Coherence Tomography Angiography approach

      Deep inside Multifocal Choroiditis: an Optical Coherence Tomography Angiography approach

      The aim of the study was to report the clinical utility of optical coherence tomography angiography (OCT-A) in characterizing and differentiating inflammatory lesions and choroidal neovascularization (CNV) in multifocal choroiditis (MFC). A patient affected by MFC complaining central visual loss and scotoma in his left eye was fully investigated with dye-based angiographies, structural OCT and OCT-A. A reactivation of macular CNV was initially suspected, while OCT-A revealed the absence of any decorrelation signal both over the retinal pigment epithelium (RPE) and between RPE and Bruchs’ membrane. OCT-A is a promising tool in detecting inflammatory CNV and in differentiating CNV from ...

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    9. Theoretical development of a magnetic force and an induced motion in elastic media for a magneto-motive technique

      Theoretical development of a magnetic force and an induced motion in elastic media for a magneto-motive technique

      The theoretical development of a magnetic force and an induced motion while applying a magnetic field to magnetic nanoparticles in elastic media is described. An analytical expression for tissue-surface displacement derived from Mindlin’s theory of elasticity in semi-infinite media was used to analyze the magneto-motive technique. The initial motion of the magnetic nanoparticles is driven by a constant magnetic force that displays a dampened transient motion before steady-state movement at twice the modulation frequency of the applied sinusoidal magnetic field. The motion of the nanoparticles at double the modulation frequency originated from the magnetic force being proportional to the ...

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    10. Epiretinal membrane as a source of errors during the measurement of peripapillary nerve fibre thickness using spectral-domain optical coherence tomography (SD-OCT)

      Epiretinal membrane as a source of errors during the measurement of peripapillary nerve fibre thickness using spectral-domain optical coherence tomography (SD-OCT)

      Purpose We aimed to examine the extent to which measurement errors in the determination of retinal nerve fibre layer (RNFL) using spectral-domain optical coherence tomography (SD-OCT) occur in cases of epiretinal membrane and whether systematic deviations are found in the values obtained. Methods A macular scan and a circumpapillary scan were performed on 97 eyes of 97 patients using SD-OCT. Group 1 comprised 53 patients with epiretinal membrane at an age of 70 ± 4.8 years (median ± average absolute deviation). Group 2 consisted of 44 patients without any macular pathologies (median age 70 ± 5.8 years). Differences in the thickness ...

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    11. Optical Coherence Tomography: Clinical Applications in Gastrointestinal Endoscopy (Book Chapter)

      Optical Coherence Tomography: Clinical Applications in Gastrointestinal Endoscopy (Book Chapter)

      Optical coherence tomography (OCT) is a high-resolution imaging modality that uses principles of light interferometry. It has achieved clinical application in several other specialties such as ophthalmology and cardiology where its high resolution and deeper penetration into the surface permits much more detailed examination of the mucosa. In the field of gastroenterology, the technology has evolved through several iterations beginning with a focal magnifying imaging technique and evolving into currently a widefield imaging modality that can scan a relatively large area of mucosa with high resolution. OCT has been used to detect dysplasia in Barrett’s esophagus, differentiate between inflammatory ...

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    12. Multi-modality Optical Imaging of Rat Kidney Dysfunction: In Vivo Response to Various Ischemia Times

      Multi-modality Optical Imaging of Rat Kidney Dysfunction: In Vivo Response to Various Ischemia Times

      We observed in vivo kidney dysfunction with various ischemia times at 30, 75, 90, and 120 min using multi-modality optical imaging: optical coherence tomography (OCT), Doppler OCT (DOCT), and two-photon microscopy (TPM). We imaged the renal tubule lumens and glomerulus at several areas of each kidney before, during, and after ischemia of 5-month-old female Munich-Wistar rats. For animals with 30 and 75 min ischemia times, we observed that all areas were recovered after ischemia, that tubule lumens were re-opened and the blood flow of the glomerulus was re-established. For animals with 90 and 120 min ischemia times, we observed unrecovered ...

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    13. The Role of Intracoronary Plaque Imaging with Intravascular Ultrasound, Optical Coherence Tomography, and Near-Infrared Spectroscopy in Patients with Coronary Artery Disease

      The Role of Intracoronary Plaque Imaging with Intravascular Ultrasound, Optical Coherence Tomography, and Near-Infrared Spectroscopy in Patients with Coronary Artery Disease

      The development of multiple diagnostic intracoronary imaging modalities has increased our understanding of coronary atherosclerotic disease. These imaging modalities, intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near-infrared spectroscopy (NIRS), have provided a method to study plaques and introduced the concept of plaque vulnerability. They are being increasingly used for percutaneous coronary intervention (PCI) optimization and are invaluable tools in research studying the pathophysiology of acute coronary syndrome (ACS), in-stent thrombosis and in-stent restenosis. IVUS has the ability to visualize the intracoronary lumen and the vessel wall and can be used to detect early atherosclerotic disease even in the setting ...

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    14. Intraocular foreign body removal: a novel technique using intraoperative imaging

      Intraocular foreign body removal: a novel technique using intraoperative imaging

      We describe a case illustrating a new technique of using intraoperative optical coherence tomography (IOCT) for foreign body removal from the limbus and cornea. In this case, fragments of a fish hook in the temporal limbus and cornea were identified on the OCT. The residual pieces were then removed, assisted by high-resolution, real-time cross-sectional imaging, IOCT. While this technique involves steep learning curve, we believe that it is safe for the patient and helps surgeon with instant decision making and reduce orbital manipulation.

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    15. Use of Optical Coherence Tomography in the Eyes of Children

      Use of Optical Coherence Tomography in the Eyes of Children

      OCT has found its niche within virtually all ophthalmic subspecialties, be it glaucoma, retina/vitreous, or anterior segment. OCT’s role in the diagnosis, management, and treatment of pediatric eye disease continues to evolve. Monumental gains have been made in our understanding of various physiologic principles and pathological processes as a result of this relatively new technology. While not intended to be an exhaustive catalogue of the opportunities afforded by OCT, this chapter should provide the well-rounded pediatric ophthalmologist with the appropriate framework to better appreciate this new technology and its role in pediatric eye disease.

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    16. Two-year Optical Coherence Tomography Findings after Balloon-Only Treatment of Bioresorbable Scaffold Restenosis in a Calcified Coronary Lesion: A Case Report

      Two-year Optical Coherence Tomography Findings after Balloon-Only Treatment of Bioresorbable Scaffold Restenosis in a Calcified Coronary Lesion: A Case Report

      We report a case of a 65-year-old female patient treated with an everolimus-eluting bioresorbable scaffold (BRS) after rotational atherectomy of a severely calcified lesion of the left anterior descending coronary artery. The implanted BRS restenosed 10 months after implantation and was treated with a scoring balloon followed by drug-eluting balloons with good immediate and long-term results. To the best of our knowledge, this is the first report of a balloon-only treatment of a restenosis occurring more than 6 months after BRS implantation; angiographic and optical coherence tomography images after treatment and at two-year follow-up are presented.

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    17. Intravascular MRI for Plaque Characterization: Are We Close to Reality?

      Intravascular MRI for Plaque Characterization: Are We Close to Reality?

      Non-invasive external magnetic resonance imaging (MRI) of large vessel atherosclerosis is a robust and promising imaging modality that can be applied for the evaluation of the atherosclerotic process in large vessels. However, it requires expertise for setup and time for data acquisition and analysis. Intravascular MRI is a promising tool, but its use remains at the pre-clinical stage within selected research groups. In this review, the current status and future role of intravascular MRI for atherosclerotic plaque characterization are summarized, along with important challenges which will be necessary to overcome prior to the wide adoption of this technique.

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    18. Optical coherence tomography impacts the evaluation of visual pathway tumors

      Optical coherence tomography impacts the evaluation of visual pathway tumors

      The objective of this systematic literature review is to assess the role of retinal optical coherence tomography (OCT) in the evaluation of patients with tumors of the visual pathway. We performed a PubMed database search according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The search was restricted to articles published in English between 2000 and 2016, with at least 10 human adult participants enrolled. Twenty-seven articles met the eligibility criteria. All studies investigated tumors of the anterior visual pathway. Both time-domain and spectral-domain OCT technologies were used and the role of OCT as diagnostic ...

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    19. Impact of optical coherence tomography- and coronary angioscopy-assessed neointimal tissue characteristics on occurrence of periprocedural myonecrosis in patients with in-stent restenosis

      Impact of optical coherence tomography- and coronary angioscopy-assessed neointimal tissue characteristics on occurrence of periprocedural myonecrosis in patients with in-stent restenosis

      Several characteristics of neointimal tissues, including neoatherosclerotic progression, have been reported in lesions with in-stent restenosis (ISR). However, the effects of these characteristics on outcomes after percutaneous coronary intervention (PCI) for ISR lesions remain unclear. We assessed the relationships between neointimal tissue characteristics and the occurrence of periprocedural myonecrosis (PMN) after PCI in ISR lesions. We investigated 72 ISR lesions in 72 patients with stable angina pectoris (SAP) who underwent pre- and post-revascularization optical coherence tomography (OCT) and coronary angioscopy (CAS). All lesions were classified as with PMN, defined by an elevated peak high-sensitivity cardiac troponin-T level during the 24-h ...

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    20. Alzheimer’s disease: A review of its visual system neuropathology. Optical coherence tomography—a potential role as a study tool in vivo

      Alzheimer’s disease: A review of its visual system neuropathology. Optical coherence tomography—a potential role as a study tool in vivo

      Alzheimer’s disease (AD) is a prevalent, long-term progressive degenerative disorder with great social impact. It is currently thought that, in addition to neurodegeneration, vascular changes also play a role in the pathophysiology of the disease. Visual symptoms are frequent and are an early clinical manifestation; a number of psychophysiologic changes occur in visual function, including visual field defects, abnormal contrast sensitivity, abnormalities in color vision, depth perception deficits, and motion detection abnormalities. These visual changes were initially believed to be solely due to neurodegeneration in the posterior visual pathway. However, evidence from pathology studies in both animal models of ...

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    21. Fractional flow reserve-guided coronary angioplasty using paclitaxel-coated balloons without stent implantation: feasibility, safety and 6-month results by angiography and optical coherence tomography

      Fractional flow reserve-guided coronary angioplasty using paclitaxel-coated balloons without stent implantation: feasibility, safety and 6-month results by angiography and optical coherence tomography

      Background Percutaneous coronary interventions (PCI) with drug-coated balloons (DCB) might be a promising trade-off between balloon angioplasty and drug-eluting stents, since DCB inhibit neointimal proliferation and limit duration of dual antiplatelet therapy. We investigated the safety, feasibility, and 6-month results of fractional flow reserve (FFR)-guided use of the paclitaxel-coated SeQuent Please ® balloon without stenting for elective PCI of de novo lesions. Methods and results In 46 patients (54 lesions) with stable symptomatic coronary artery disease (CAD), a FFR-guided POBA (plain old balloon angioplasty) was performed. In case of a sufficient POBA result with residual stenosis < 40 %, FFR > 0.8 ...

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      Mentions: Sylvia Otto
    22. Impact of chronic kidney disease stages on atherosclerotic plaque components on optical coherence tomography in patients with coronary artery disease

      Impact of chronic kidney disease stages on atherosclerotic plaque components on optical coherence tomography in patients with coronary artery disease

      The progression of coronary atherosclerosis has been influenced by the presence of chronic kidney disease (CKD). This study investigated the impact of CKD stages on coronary plaque components observed on optical coherence tomography (OCT). We investigated 296 native coronary lesions with stable angina pectoris treated with stent implantation. All lesions were divided into the three groups according to the values of estimated glomerular filtration rate (eGFR, mL min −1 1.73 m −2 ): the non-CKD group (eGFR ≥60, n = 142), CKD group (15 ≤ eGFR < 60, n = 126), and end-stage kidney disease (ESKD) group (eGFR <15 and/or hemodialysis, n = 28 ...

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