1. 1-24 of 311 1 2 3 4 ... 11 12 13 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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
    6. 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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    7. 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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    8. 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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    9. Intravascular ultrasound and optical coherence tomography imaging of coronary atherosclerosis

      Intravascular ultrasound and optical coherence tomography imaging of coronary atherosclerosis

      Invasive imaging modalities, in particular intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have become established tools for the in vivo study of coronary atherosclerosis. Their use in clinical studies has confirmed histopathological observations that certain important plaque features, such as thin fibrous caps and large lipid cores, are associated with plaque rupture, the precipitating event for the majority of myocardial infarctions. Serial imaging studies have also successfully been used for the evaluation of potential disease modifying pharmacological agents. Recent prospective IVUS studies have confirmed specific baseline imaging features associated with subsequent adverse clinical outcomes, although absolute event rates were ...

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    10. Retinal pigment epithelial detachment associated with retinal pigment epithelium thinning revealed by optical coherence tomography

      Retinal pigment epithelial detachment associated with retinal pigment epithelium thinning revealed by optical coherence tomography

      Purpose To clarify the characteristics and outcomes of unusual retinal pigment epithelial detachments (PEDs). These PEDs had one or several sites of apparent thinning of the RPE, or no RPE at all, as shown on optical coherence tomography (OCT). Methods Eight cases with PEDs showed apparent thinning of the RPE in the roof of the PED at one or more sites on OCT. Color fundus photographs, fundus examination records, fluorescein angiograms (FAs) and/or indocyanine green angiograms (ICGAs), obtained with simultaneous OCT using Spectralis ® , and fundus autofluorescence were evaluated. Macular findings, prior to baseline PED detection, were investigated in three ...

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    11. Optical Coherence Tomography: Technology and Applications Second Edition (Textbook)

      Optical Coherence Tomography: Technology and Applications Second Edition (Textbook)

      New medical imaging technologies can improve the diagnosis and clinical management of many diseases. Furthermore, advanced imaging also contributes to a better understanding of pathogenesis and therefore to the development of new pharmaceuticals and novel therapies. Thus, imaging plays a critical role in modern medical research and clinical practice. Noninvasive or minimally invasive imaging techniques have revolutionized diagnostic medicine during the last decades, e.g., X-ray computed tomography (CT), magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), radioisotope imaging (position emission tomography (PET)), single-photon emission computed tomography (SPECT), and diffuse optical tomography (DOT). These techniques permit three-dimensional visualization; however ...

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    12. Real-time cancer diagnosis during prostate biopsy: ex vivo evaluation of full-field optical coherence tomography (FFOCT) imaging on biopsy cores

      Real-time cancer diagnosis during prostate biopsy: ex vivo evaluation of full-field optical coherence tomography (FFOCT) imaging on biopsy cores

      Objectives To evaluate the diagnostic accuracy (Acc) of full-field optical coherence tomography (FFOCT) for cancer detection on prostate biopsy. Materials and methods Thirty-eight consecutive patients with elevated PSA and/or suspicious digital rectal examination were prospectively included. For each patient, 1–10 cores were randomly selected and imaged with FFOCT immediately after sampling. The images obtained were de-identified and analyzed by three pathologists blinded to the results of pathological evaluation. The overall average Acc was measured, as well as sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV and NPV). The Acc learning curve was assessed by multivariate logistic ...

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    13. Translating Intravascular Optical Coherence Tomography from a Research to a Clinical Tool

      Translating Intravascular Optical Coherence Tomography from a Research to a Clinical Tool

      Intravascular optical coherence tomography (IVOCT) continues to be a hot topic as a method for studying vulnerable plaque in research laboratories across the globe. It is also growing in popularity as a tool for interventional cardiologists to guide percutaneous coronary intervention (PCI). The power of IVOCT for diagnosis of thin-capped fibroatheromas (TCFAs) has yet to receive mainstream clinical attention due to the fact that clinicians still do not have a protocol to follow if TCFA are identified and that TCFA identification requires extensive training in IVOCT image analysis—it is not yet an automated process. In this review, we will ...

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    14. Optical Coherence Tomography for the Assessment of Coronary Artery Disease

      Optical Coherence Tomography for the Assessment of Coronary Artery Disease

      Angiography remains the gold standard for assessment of atherosclerotic impairment of coronary arteries and for guidance of coronary intervention. Angiography, as a main limitation, only depicts the luminal narrowings caused by coronary plaques, without showing the structures located beneath, such as the atherosclerotic lesions or the vessel wall. Intravascular imaging modalities are currently adopted to circumvent angiographic limitations. Optical coherence tomography (OCT)) is a novel imaging technique that uses infrared lights and can study atherosclerotic plaques and stented segments with extreme accuracy. Compared to intravascular ultrasound (IVUS) , OCT has a much higher resolution; this is at the expense of the ...

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      Mentions: Francesco Prati
    15. Mathematical Methods of Optical Coherence Tomography (Book Chapter)

      Mathematical Methods of Optical Coherence Tomography (Book Chapter)

      In this chapter a general mathematical model of Optical Coherence Tomography (OCT) is presented on the basis of the electromagnetic theory. OCT produces high-resolution images of the inner structure of biological tissues. Images are obtained by measuring the time delay and the intensity of the backscattered light from the sample considering also the coherence properties of light. The scattering problem is considered for a weakly scattering medium located far enough from the detector. The inverse problem is to reconstruct the susceptibility of the medium given the measurements for different positions of the mirror. Different approaches are addressed depending on the ...

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    16. Interventional Cardiology Imaging (Textbook)

      Interventional Cardiology Imaging (Textbook)

      Ever since the establishment of invasive coronary angiography, the limitations of the technique have not gone unnoticed. As a result, multiple invasive imaging modalities have been developed in an attempt to characterize the true severity of coronary artery disease as well as guide the percutaneous coronary interventions. Invasive imaging modalities have included ultrasound, optical, and chemographic technologies. Moreover, physiological assessment of the degree of the coronary blood fl ow has also been performed through fractional and coronary fl ow assessments. This book provides an overview of the current available invasive coronary imaging modalities in an attempt to present a concise ...

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    17. High-definition optical coherence tomography intrinsic skin ageing assessment in women: a pilot study

      High-definition optical coherence tomography intrinsic skin ageing assessment in women: a pilot study

      Several non-invasive two-dimensional techniques with different lateral resolution and measurable depth range have proved to be useful in assessing and quantifying morphological changes in skin ageing. Among these, only in vivo microscopy techniques permit histometric measurements in vivo. Qualitative and quantitative assessment of chronological (intrinsic) age-related (IAR) morphological changes of epidermis, dermo-epidermal junction (DEJ), papillary dermis (PD), papillary-reticular dermis junction and reticular dermis (RD) have been performed by high-definition optical coherence tomography in real time 3-D. HD-OCT images were taken at the internal site of the right upper arm. Qualitative HD-OCT IAR descriptors were reported at skin surface, at epidermal ...

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    18. Metrics of the normal anterior sclera: imaging with optical coherence tomography

      Metrics of the normal anterior sclera: imaging with optical coherence tomography

      Background To investigate anterior scleral thickness in a cohort of healthy subjects using enhanced depth imaging anterior segment optical coherence tomography. Methods Observational case series. The mean scleral thickness in the inferonasal, inferotemporal, superotemporal, and superonasal quadrant was measured 2 mm from the scleral spur on optical coherence tomography in healthy volunteers. Results Fifty-three eyes of 53 Caucasian patients (25 male and 28 female) with an average age of 48.6 years (range: 18 to 92 years) were analysed. The mean scleral thickness was 571 μm (SD 84 μm) in the inferonasal quadrant, 511 μm (SD 80 μm) in the ...

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    19. Enhanced-depth optical coherence tomography for imaging horizontal rectus muscles in Graves’ orbitopathy

      Enhanced-depth optical coherence tomography for imaging horizontal rectus muscles in Graves’ orbitopathy

      Graves’ orbitopathy (GO) is an extraocular eye disease with symptoms ranging from minor discomfort from dry eyes to strabismus and visual loss. One of the hallmarks of active GO is visible hyperemia at the insertion of the extraocular muscles. The aim of the present study was to evaluate the use of enhanced-depth imaging spectral domain anterior segment optical coherence tomography (EDI SD AS-OCT) for detecting pathological changes in horizontal recti muscles of patients with GO. Methods Prospective cross sectional study of 27 eyes. Only women were included. EDI AS-OCT was used to measure the thickness of the tendons of the ...

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    20. Marker-Free Tracking of Facet Capsule Motion Using Polarization-Sensitive Optical Coherence Tomography

      Marker-Free Tracking of Facet Capsule Motion Using Polarization-Sensitive Optical Coherence Tomography

      We proposed and tested a method by which surface strains of biological tissues can be captured without the use of fiducial markers by instead, utilizing the inherent structure of the tissue. We used polarization-sensitive optical coherence tomography (PS OCT) to obtain volumetric data through the thickness and across a partial surface of the lumbar facet capsular ligament during three cases of static bending. Reflectivity and phase retardance were calculated from two polarization channels, and a power spectrum analysis was performed on each a-line to extract the dominant banding frequency (a measure of degree of fiber alignment) through the maximum value ...

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    21. Enhanced-depth optical coherence tomography for imaging horizontal rectus muscles in Graves' orbitopathy

      Enhanced-depth optical coherence tomography for imaging horizontal rectus muscles in Graves' orbitopathy

      Purpose Graves’ orbitopathy (GO) is an extraocular eye disease with symptoms ranging from minor discomfort from dry eyes to strabismus and visual loss. One of the hallmarks of active GO is visible hyperemia at the insertion of the extraocular muscles. The aim of the present study was to evaluate the use of enhanced-depth imaging spectral domain anterior segment optical coherence tomography (EDI SD AS-OCT) for detecting pathological changes in horizontal recti muscles of patients with GO. Methods Prospective cross sectional study of 27 eyes. Only women were included. EDI AS-OCT was used to measure the thickness of the tendons of ...

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    22. Changes in macular layers in the early course of non-arteritic ischaemic optic neuropathy

      Changes in macular layers in the early course of non-arteritic ischaemic optic neuropathy

      Purpose To characterise the changes of the retinal layers in patients with acute anterior ischaemic optic neuropathy (AION), aiming to identify imaging markers for predicting the residual visual function. Methods This was a retrospective review of consecutive patients with unilateral AION from January 2010 to December 2013. We analysed affected eyes at baseline and 1 month later, compared to fellow healthy eyes. Utilising novel image analysis software, we conducted algorithmic segmentation in layers and division in early treatment of diabetic retinopathy study (ETDRS) quadrants of optical coherence tomography images of the macula. Pearson product moment regression analysis of retinal layer ...

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    23. Correlation between visual acuity changes and optical coherence tomography morphological findings in idiopathic epiretinal membranes

      Correlation between visual acuity changes and optical coherence tomography morphological findings in idiopathic epiretinal membranes

      Purpose To analyze the influence of spectral-domain optical coherence tomography (SD-OCT) features on visual acuity changes in patients with idiopathic epiretinal membranes (ERMs). Methods Seventy-nine eyes of 71 patients were included in this study. SD-OCT was performed for all patients; data were collected upon ERM diagnosis and at the final visit. The patients were divided into subgroups based on their SD-OCT features. The initial best corrected visual acuity (BCVA) and changes in BCVA for each subgroup were compared. A multivariate analysis was performed to assess the factors associated with changes in BCVA. Results During a mean follow-up period of 20 ...

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    24. Staging of development in Terrien's degeneration based on corneal curvatures detected by optical coherence tomography

      Staging of development in Terrien's degeneration based on corneal curvatures detected by optical coherence tomography

      Purpose We aimed to explore a new classification system based on the change of focal corneal curvatures and corneal thickness in Terrien’s corneal degeneration with optical coherence tomography. Methods This was a cross-sectional study. Ninety eyes of 59 patients with Terrien’s degeneration were examined with slit lamp biomicroscopy, Orbscan II corneal tomography and the Visante OCT system, and were staged according to Süveges’s classification. Results The ratio of female to male patients was 1.57:1. The ratio of bilateral to unilateral lesions was 1.27:1. The occurrence of bilateral lesion was higher in males ...

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