1. 1-24 of 529 1 2 3 4 ... 20 21 22 »
    1. Atlas of Coronary Intravascular Optical Coherence Tomography (Textbook)

      Atlas of Coronary Intravascular Optical Coherence Tomography (Textbook)

      This atlas is a practical and fully illustrated guide to the use of intravascular OCT in diagnosis and treatment of coronary artery disease. It consists of two parts. The first part of the book provides a systematic introduction to coronary imaging with OCT. It describes how to interpret images and describes abnormal findings seen in atherosclerosis, complications after intervention, and stent assessment. The second part of the book presents real-life case studies that show how OCT is used in clinical practice in Mount Sinai to assess the disease, select appropriate treatment, and evaluate complications and results. Each case includes a ...

      Read Full Article
    2. Pearls and pitfalls of optical coherence tomography angiography in the multimodal evaluation of uveitis

      Pearls and pitfalls of optical coherence tomography angiography in the multimodal evaluation of uveitis

      Background Optical coherence tomography angiography (OCTA) employs a novel imaging algorithm that detects the amplitude or phase decorrelation of blood cell movement. It thus provides a flow map with depth-resolved visualization of the various vascular layers in the posterior pole of the eye including the retina capillary plexus and the choroid. In the past 3 years, the number of research papers on the subject of OCTA in retinal diseases has grown exponentially including important applications in the field of uveitis. While the study of OCTA in uveitic diseases has gained remarkable relevance worldwide, interpretation can be challenging, and many limitations ...

      Read Full Article
      Mentions: UCLA Vishali Gupta
    3. Quantitative changes in flow density in patients with adult-onset foveomacular vitelliform dystrophy: an OCT angiography study

      Quantitative changes in flow density in patients with adult-onset foveomacular vitelliform dystrophy: an OCT angiography study

      Purpose To quantitatively compare the flow density, the retinal thickness, and the area of the foveal avascular zone (FAZ) between patients with adult-onset foveomacular vitelliform dystrophy (AOFVD) and a healthy controls. Methods Thirteen eyes (eight patients) with AOFVD and 13 matched eyes (13 patients) without any ocular pathology were included in this study. A 6 × 6 mm optical coherence tomography angiography (OCTA) scan was performed for every included eye. The flow density (superficial retinal vascular layer, deep retinal vascular layer and choriocapillary layer), retinal thickness and FAZ (superficial retinal vascular layer and deep retinal vascular layer) were subsequently analyzed. Results ...

      Read Full Article
    4. Medium chromatic dispersion calculation and correction in spectral-domain optical coherence tomography

      Medium chromatic dispersion calculation and correction in spectral-domain optical coherence tomography

      A method for determining and correcting distortions in spectral-domain optical coherence tomography images caused by medium dispersion was developed. The method is based on analysis of the phase distribution of the interference signal recorded by an optical coherence tomography device using an iterative approach to find and compensate for the effect of a medium’s chromatic dispersion on point-spread function broadening in optical coherence tomography. This enables compensation of the impact of medium dispersion to an accuracy of a fraction of a radian (units of percent) while avoiding additional measurements and solution of the optimization problem. The robustness of the ...

      Read Full Article
    5. Comparative assessment of three drug eluting stents with different platforms but with the same biodegradable polymer and the drug based on quantitative coronary angiography and optical coherence tomography at 12-month follow-up

      Comparative assessment of three drug eluting stents with different platforms but with the same biodegradable polymer and the drug based on quantitative coronary angiography and optical coherence tomography at 12-month follow-up

      The aim of this study was to compare neointima proliferation in three drug-eluting stents (DES) produced by the same company (Balton, Poland) which are covered with a biodegradable polymer and elute sirolimus (concentration: 1.0 and 1.2 µg/mm 2 ), but have different stent platforms and strut thickness: stainless steel Prolim ® (115 µm) and BiOSS LIM ® (120 µm) and cobalt-chromium Alex ® (70 µm). We analyzed data of patients with quantitative coronary angiography (QCA) and optical coherence tomography (OCT) at 12 months from BiOSS LIM Registry, Prolim Registry and Alex OCT clinical trial. There were 56 patients enrolled, in whom ...

      Read Full Article
      Mentions: Dariusz Dudek
    6. Ocular anatomic changes for different accommodative demands using swept-source optical coherence tomography: a pilot study

      Ocular anatomic changes for different accommodative demands using swept-source optical coherence tomography: a pilot study

      Purpose The purpose of our study was to assess the changes in ocular parameters for different accommodative demands using a new optical biometer based on swept-source optical coherence tomography (SS-OCT). Methods Seven subjects were included in this pilot study, and only one eye per participant was analyzed. Each eye was measured six times with the optical biometer IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany). As this instrument is not able to change the vergence of the stimulus, to enable measurements at different accommodative states, a tilted first-surface mirror attached to the optical biometer was used to place the fixation stimulus ...

      Read Full Article
    7. CNNs Enable Accurate and Fast Segmentation of Drusen in Optical Coherence Tomography

      CNNs Enable Accurate and Fast Segmentation of Drusen in Optical Coherence Tomography

      Optical coherence tomography (OCT) is used to diagnose and track progression of age-related macular degeneration (AMD). Drusen, which appear as bumps between Bruch’s membrane (BM) and the retinal pigment epithelium (RPE) layer, are among the most important biomarkers for staging AMD. In this work, we develop and compare three automated methods for Drusen segmentation based on the U-Net convolutional neural network architecture. By cross-validating on more than 50, 000 annotated images, we demonstrate that all three approaches achieve much better accuracy than a current state-of-the-art method. Highest accuracy is achieved when the CNN is trained to segment the BM ...

      Read Full Article
    8. The use of optical coherence tomography angiography in pachychoroid spectrum diseases: a concurrent comparison with dye angiography

      The use of optical coherence tomography angiography in pachychoroid spectrum diseases: a concurrent comparison with dye angiography

      Purpose The study objective was to compare dye angiography and optical coherence tomography angiography (OCTA) in detecting choroidal neovascuarization (CNV) in patients presenting with pachychoroid features and flat irregular pigment epithelial detachment (PED). Methods Nineteen eyes of 17 patients, presenting with flat PED and pachychoroid features, and without age-related macular degeneration or any other degenerative change, were analyzed. Fuorescein angiography (FA)/Indocyanine green angiography (ICGA) and OCTA were performed during the same visit. Subfoveal choroidal thickness was measured by enhanced depth imaging using spectral domain optical coherence tomography. Results The mean age of the patients was 59.1 years. Mean ...

      Read Full Article
    9. Automated Segmentation of the Choroid in EDI-OCT Images with Retinal Pathology Using Convolution Neural Networks

      Automated Segmentation of the Choroid in EDI-OCT Images with Retinal Pathology Using Convolution Neural Networks

      The choroid plays a critical role in maintaining the portions of the eye responsible for vision. Specific alterations in the choroid have been associated with several disease states, including age-related macular degeneration (AMD), central serous chorioretinopathy, retinitis pigmentosa and diabetes. In addition, choroid thickness measures have been shown as a predictive biomarker for treatment response and visual function. Where several approaches currently exist for segmenting the choroid in optical coherence tomography (OCT) images of healthy retina, very few are capable of addressing images with retinal pathology. The difficulty is due to existing methods relying on first detecting the retinal boundaries ...

      Read Full Article
    10. In vitro remodeling and structural characterization of degradable polymer scaffold-based tissue-engineered vascular grafts using optical coherence tomography

      In vitro remodeling and structural characterization of degradable polymer scaffold-based tissue-engineered vascular grafts using optical coherence tomography

      Non-destructive imaging strategies to monitor long-term cultures is essential for vascular engineering. The goal of this study is to investigate whether optical coherence tomography (OCT) can be a suitable approach to monitor the long-term remodeling process of biodegradable polymeric scaffold-based tissue-engineered vascular grafts (TEVG) after pulsatile stimulation and to observe polymeric scaffold degradation during bioreactor cultivation. In the present study, a perfusion system driven by a ventricular assist device was provided for a three-dimensional culture system as a pulsatile force. We characterized the structural features of wall thickness and polyglycolic acid degradation based on optical signal attenuation using catheter-based OCT ...

      Read Full Article
    11. An Approach for Needle Based Optical Coherence Elastography Measurements

      An Approach for Needle Based Optical Coherence Elastography Measurements

      While navigation and interventional guidance are typically based on image data, the images do not necessarily reflect mechanical tissue properties. Optical coherence elastography (OCE) presents a modality with high sensitivity and very high spatial and temporal resolution. However, OCE has a limited field of view of only 2–5 mm depth. We present a side-facing needle probe to image externally induced shear waves from within soft tissue. A first method of quantitative needle-based OCE is provided. Using a time of flight setup, we establish the shear wave velocity and estimate the tissue elasticity. For comparison, an external scan head is ...

      Read Full Article
    12. Refining Coats’ disease by ultra-widefield imaging and optical coherence tomography angiography

      Refining Coats’ disease by ultra-widefield imaging and optical coherence tomography angiography

      Purpose The purpose of our study was to describe ultra-widefield (UWF) imaging and optical coherence tomography angiography (OCT-A) findings in affected and fellow eyes of patients with Coats’ disease. Methods Consecutive patients affected by Coats’ disease were prospectively recruited at the Department of Ophthalmology, San Raffaele Hospital, Milan, Italy in this cross-sectional, observational study. Patients underwent UWF color fundus photographs, UWF green autofluorescence, UWF fluorescein angiography (FA), optical coherence tomography (OCT), with 3 × 3 mm and 6 × 6 mm OCT-A scans of the macula. Images were qualitatively evaluated by two independent operators for the presence of pathology. Results Eleven patients ...

      Read Full Article
    13. Invasive assessment of coronary artery disease

      Invasive assessment of coronary artery disease

      oronary artery disease is associated to high mortality and morbidity rates and an accurate diagnostic assessment during heart catheterization has a fundamental role in prognostic stratification and treatment choices. Coronary angiography has been integrated by intravascular imaging modalities, namely intravascular ultrasound and optical coherence tomography, which allow the precise quantification of the atherosclerotic burden of coronary arteries. The hemodynamic relevance of a given coronary stenosis can be assessed using stress or resting indexes: fractional flow reserve and instantaneous wave-free ratio are both coronary flow surrogates, used to guide percutaneous coronary interventions. This review summarizes the current state-of-the-art of invasive diagnostic ...

      Read Full Article
    14. Optical Coherence Tomography to Differentiate Papilledema from Pseudopapilledem

      Optical Coherence Tomography to Differentiate Papilledema from Pseudopapilledem

      Purpose of Review Mild papilledema may be difficult to distinguish by clinical observation from pseudopapilledema. An accurate diagnosis is critical to avoid invasive workup and unwarranted treatment. In this review, we focus on the development and subsequent role of optical coherence tomography (OCT) in detecting and differentiating optic nerve head drusen (ONHD) from papilledema and other causes of acquired swelling of the optic disc. Recent Findings Newer OCT technologies which permit deeper penetration to improve detection of ONHD were also reviewed. Enhanced depth imaging (EDI) spectral-domain OCT and swept-source (SS) OCT are currently recognized as the most reliable and sensitive ...

      Read Full Article
    15. Introduction to swept source optical coherence tomography angiography

      Introduction to swept source optical coherence tomography angiography

      Swept source optical coherence tomography (OCT) technology and OCT-angiography (OCT-A) are two recent developments that have the potential to significantly change our understanding of retinal pathology and retinal vascular pathophysiology. In order to correctly use these technologies to their full diagnostic potential, a thorough understanding of the technology as well as its benefits and limitations is essential. The aim of this review article is to provide an introductory understanding of how swept source OCT with a 1050 nm wavelength differs from conventional spectral domain OCT using 840 nm wavelength, and what the benefits are. The OCTARA™ swept source OCT angiography ...

      Read Full Article
    16. Optical coherence tomography as a marker of vision in children with optic pathway gliomas

      Optical coherence tomography as a marker of vision in children with optic pathway gliomas

      Purpose Optic pathway gliomas (OPG) represent an important cause of visual loss in pediatric population. The indication of treatment is based on clinical or neuroimaging progression. Visual acuity loss is the most important symptom of disease progression, but children with OPG are frequently unable to complete the testing of visual function. Optical coherence tomography (OCT) was suggested as an objective tool for visual assessment. A literature review was performed in order to determine the role of retinal OCT as a surrogate marker of vision in children with OPG. Methods The search was performed using PubMed, Embase, and Web of Science ...

      Read Full Article
    17. Early detection of radiation maculopathy using OCTA imaging: a case report

      Early detection of radiation maculopathy using OCTA imaging: a case report

      Objective To report the case of a 62-year-old female treated with proton beam radiotherapy for a choroidal melanoma. Results After irradiation, the patient was followed-up regularly. Although clinical examination and spectral domain optical coherence tomography (OCT) showed no signs of radiation maculopathy, OCT angiography (OCTA) enabled detection of abnormalities (rarefaction of the vessel at both retinal capillary plexuses) probably related to the radiation maculopathy. Conclusion OCTA could help in the early detection of radiation maculopathy. This could be an important tool to monitor patients and discuss earlier treatments.

      Read Full Article
    18. Quantitative analysis of photoreceptor layer reflectivity on en-face optical coherence tomography as an estimator of cone density

      Quantitative analysis of photoreceptor layer reflectivity on en-face optical coherence tomography as an estimator of cone density

      Background To investigate whether outer retinal reflectivity on en-face Optical coherence tomography (OCT) can be considered as an estimator of cone density measured in the same area. Methods Forty-one points of comparisons were studied in 9 eyes ( n = 6 patients) presenting maculopathies with various degrees of impairment of the photoreceptor layer. The inner segment ellipsoid zone (EZ), interdigitation zone (IZ), and retinal pigment epithelium (RPE) reflectivity were measured on coronal reconstruction of the photoreceptor layer using homemade dedicated software (Matlab, MathWorks Inc., Natick, USA). The cone metrics were measured in the same perifoveal region of interest using a high-resolution flood ...

      Read Full Article
    19. Optical coherence tomography of Bitot’s spot in vitamin A deficiency

      Optical coherence tomography of Bitot’s spot in vitamin A deficiency

      Background Severe vitamin A deficiency can manifest as xerophthalmia in the eyes resulting in clinical features, such as night blindness, conjunctival xerosis, corneal xerosis, corneal ulcers and Bitot’s spots. We present the multimodal imaging results of a patient who underwent an ileocecal resection for Crohn’s disease and presented with nyctalopia and bilateral central scotomas. Method Report of a single case. Results The patient’s best-corrected visual acuity was 20/50 in the right eye and 20/32 in the left eye. Anterior segment examination identified small elevated focal translucent foamy Bitot’s spots on the superficial bulbar conjunctiva ...

      Read Full Article
    20. Characteristics of retinal vessels in surgically closed macular hole: an optical coherence tomography angiography study

      Characteristics of retinal vessels in surgically closed macular hole: an optical coherence tomography angiography study

      Purpose The purpose of our study was to investigate characteristics of retinal vessels in eyes with surgically closed macular holes (MH). Methods We included patients who underwent surgery for idiopathic MH and a follow-up examination using optical coherence tomography angiography (OCTA). The area of the foveal avascular zone (FAZ) and retinal vascular densities of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were calculated on the postoperative OCTA images and compared with those of age-matched normal controls. Results Twenty-eight patients with MH and 28 controls were included. Mean postoperative FAZ areas of SCP and DCP (0.317 ± 0 ...

      Read Full Article
      Mentions: Korea University
    21. Determination of Coefficient of Thermal Expansion in High Power GaN-Based Light-Emitting Diodes via Optical Coherent Tomography

      Determination of Coefficient of Thermal Expansion in High Power GaN-Based Light-Emitting Diodes via Optical Coherent Tomography

      One of the most challenging issues when operating a high-power light-emitting diode (LED) is to conduct appropriate packaging materials for the reliable thermal management of the entire device. Generally, the considerable amount of heat produced around the junction area of the LED would transfers to the entire device, and causes thermal expansion in the packaging material. It induces strain inevitably, and hinders the output performances and possible applications of high-power LEDs. The coefficient of thermal expansion (CTE) is a physical quantity that indicates the expansion to which value a material will be upon heating. Therefore, as far as an advancement ...

      Read Full Article
    1-24 of 529 1 2 3 4 ... 20 21 22 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks