1. 1-24 of 715 1 2 3 4 ... 28 29 30 »
    1. The effect of age on the response of retinal capillary filling to changes in intraocular pressure measured by optical coherence tomography angiography

      The effect of age on the response of retinal capillary filling to changes in intraocular pressure measured by optical coherence tomography angiography

      Purpose To compare the effect of elevated intraocular pressure (IOP) on retinal capillary filling in elderly vs adult rats using optical coherence tomography angiography (OCTA). Methods The IOP of elderly (24-month-old, N = 12) and adult (6–8 month-old, N = 10) Brown Norway rats was elevated in 10 mmHg increments from 10 to 100 mmHg. At each IOP level, 3D OCT data were captured using an optical microangiography (OMAG) scanning protocol and then post-processed to obtain both structural and vascular images. Mean arterial blood pressure (MAP), respiratory rate, pulse and blood oxygen saturation were monitored non-invasively throughout each experiment. Ocular perfusion ...

      Read Full Article
    2. In Vivo Calcium Detection by Comparing Optical Coherence Tomography, Intravascular Ultrasound, and Angiography

      In Vivo Calcium Detection by Comparing Optical Coherence Tomography, Intravascular Ultrasound, and Angiography

      Objectives The aim of this study was to evaluate optical coherence tomography (OCT) and intravascular ultrasound (IVUS) versus coronary angiography in the assessment of target lesion calcification and its effect on stent expansion. Background IVUS is more sensitive than angiography in the detection of coronary artery calcium, but the relationship among IVUS, OCT, and angiography has not been studied. Methods Overall, 440 lesions (440 patients with stable angina) underwent OCT- and IVUS-guided stent implantation. Coronary calcification was evaluated using: 1) angiography; 2) IVUS (maximum calcium angle and the surface pattern); and 3) OCT (mean and maximum calcium angle, calcium length ...

      Read Full Article
    3. Prevalence, Predictors, and Clinical Presentation of a Calcified Nodule as Assessed by Optical Coherence Tomography

      Prevalence, Predictors, and Clinical Presentation of a Calcified Nodule as Assessed by Optical Coherence Tomography

      Objectives This study sought to determine the anatomic characteristics and clinical presentation associated with a calcified nodule (CN) as assessed by optical coherence tomography. Background CN is an unusual but demonstrable cause of acute coronary syndromes (ACS). Methods We studied 889 de novo culprit lesions in 889 patients (48% ACS) who underwent optical coherence tomography before intervention. CN was defined as an eruptive accumulation of nodular calcification (small fractured calcifications). Using quantitative coronary angiography, the change in the angle of the lesion between diastole and systole was measured (angiographic Δ angle). Results CN was seen in 4.2% of all lesions ...

      Read Full Article
    4. Optical Coherence Tomography Characterization of Coronary Lithoplasty for Treatment of Calcified Lesions: First Description

      Optical Coherence Tomography Characterization of Coronary Lithoplasty for Treatment of Calcified Lesions: First Description

      Objectives This study sought to determine the mechanistic effects of a novel balloon-based lithoplasty system on heavily calcified coronary lesions and subsequent stent placement using optical coherence tomography (OCT). Background The Shockwave Coronary Rx Lithoplasty System (Shockwave Medical, Fremont, California) delivers localized, lithotripsy-enhanced disruption of calcium within the target lesion (i.e., lithoplasty) for vessel preparation before stent implantation. Methods We analyzed OCT findings in 31 patients in whom lithoplasty was used to treat severely calcified stenotic coronary lesions. Results After lithoplasty, intraplaque calcium fracture was identified in 43% of lesions, with circumferential multiple fractures noted in >25%. The frequency ...

      Read Full Article
    5. Methodology for Image-driven High-resolution Additive Manufacturing Using Discretized Data Set

      Methodology for Image-driven High-resolution Additive Manufacturing Using Discretized Data Set

      Additive manufacturing of patient-specific biomedical devices from 3D medical scans involves several steps of conversion which can introduce error into the final part. This is particularly critical to the fabrication of minute anatomical features, such as microvasculature. We show a direct conversion of the raw optical coherence tomography (OCT) volumetric data into photomasks in bitmap format, which streamlines the typical process steps used in 3D printing medical scans. OCT scans of rodent retinal microvasculature and projection microstereolithography are used to fabricate a solid vascular replica and a solid volume with hollow embedded microvessels.

      Read Full Article
    6. Outcomes of Intraoperative OCT–Assisted Epiretinal Membrane Surgery from the PIONEER Study

      Outcomes of Intraoperative OCT–Assisted Epiretinal Membrane Surgery from the PIONEER Study

      Purpose To assess the retinal architecture changes that occur during epiretinal membrane (ERM) surgery, utilizing intraoperative OCT ( i OCT). Design Prospective multisurgeon single-center study. Subjects Subjects from the PIONEER i OCT study who underwent surgical intervention for management of ERM. Methods All subjects underwent vitrectomy with ERM peeling with optional internal limiting membrane (ILM) peeling. Preoperative, intraoperative, and postoperative quantitative and qualitative OCT assessments were performed. Clinical characteristics including visual acuity outcomes, central subfield thickness, and complications, including ERM recurrence and need for reoperation, were assessed at 3, 6, and 12 months after surgery for membrane peeling, as available. Main ...

      Read Full Article
    7. Intravascular imaging for characterization of coronary atherosclerosis

      Intravascular imaging for characterization of coronary atherosclerosis

      This short review surveys recent developments in coronary intravascular imaging technologies. We present an outline of the applications of intravascular imaging for guidance of percutaneous coronary interventions and imaging of atherosclerosis, along with emerging clinical evidence for use. Imaging of tissue composition is important for understanding the relation between the presence of a lesion and clinical sequelae. We describe the recent innovations to enable imaging of unstable atherosclerotic plaques, focusing on the emergence of experimental multimodal imaging technology.

      Read Full Article
    8. Pseudoexfoliation signs in the anterior segment assessed by optical coherence tomography and Scheimpflug device

      Pseudoexfoliation signs in the anterior segment assessed by optical coherence tomography and Scheimpflug device

      Objective To evaluate different anterior segment parameters in eyes with pseudoexfoliation (PSX), fellow eyes, and controls using optical coherence tomography and a Scheimpflug imaging system. Methods Three groups were studied: 44 eyes of 44 patients with PSX, 30 clinically unaffected fellow eyes, and 148 eyes of 148 healthy controls. The anterior chamber depth and volume, corneal volume and thickness, pupil diameter and corneal densitometry were measured using a Scheimpflug imaging system (Pentacam, Oculus Inc.; Wetzlar, Germany). The angle width, the length and area of the trabecular meshwork, and the iris thickness were measured using an optical coherence tomography RTVue 100 ...

      Read Full Article
    9. Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications

      Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications

      OCT has revolutionized the practice of ophthalmology over the past 10–20 years. Advances in OCT technology have allowed for the creation of novel OCT-based methods. OCT-Angiography (OCTA) is one such method that has rapidly gained clinical acceptance since it was approved by the FDA in late 2016. OCTA images are based on the variable backscattering of light from the vascular and neurosensory tissue in the retina. Since the intensity and phase of backscattered light from retinal tissue varies based on the intrinsic movement of the tissue (e.g. red blood cells are moving, but neurosensory tissue is static), OCTA ...

      Read Full Article
    10. Postnatal maturation of the fovea in Macaca mulatta using optical coherence tomography

      Postnatal maturation of the fovea in Macaca mulatta using optical coherence tomography

      Changes in the foveal anatomy during infancy are an important component in early development of spatial vision. The present longitudinal study in rhesus monkeys was undertaken to characterize the postnatal maturation of the fovea. Starting at four weeks after birth, the retinas of the left eyes of sixteen infant monkeys were imaged using spectral domain optical coherence tomography (SD OCT). Retinal scans were repeated every 30 days during the first year of life and every 60 days thereafter. Volume scans through the fovea were registered, scaled using a three surface schematic eye, and analyzed to measure foveal pit parameters. The ...

      Read Full Article
    11. Single camera spectral domain polarization-sensitive optical coherence tomography based on orthogonal channels by time divided detection

      Single camera spectral domain polarization-sensitive optical coherence tomography based on orthogonal channels by time divided detection

      We demonstrate a simple polarization-sensitive spectral-domain optical coherence tomography implement by using a single line-scan camera based on time divided detection. Two light shutters were placed on the dual assembly reference arm that provides a divided detection between the orthogonal vertical and horizontal polarized lights. The relative reflectivity and the retardance information were available by recombining the two orthogonal polarization images. This system can be employed to implement high speed polarization-sensitive OCT images.

      Read Full Article
    12. New Non-invasive Techniques to Quantify Skin Surface Strain and Sub-surface Layer Deformation of Finger-pad during Sliding

      New Non-invasive Techniques to Quantify Skin Surface Strain and Sub-surface Layer Deformation of Finger-pad during Sliding

      tudies on the variation of skin properties with gender, age and anatomical region, with regards to interaction with different materials have resulted in significant research output. Investigations on skin surface strain and sub-surface layer deformation during sliding, however, have not received as much attention. This novel study uses two non-invasive techniques, optical coherence tomography (OCT) and digital image correlation (DIC), to measure properties of the index finger of a 25 year old female when under normal and shear loading. Measurements were taken during static, and for the first time, dynamic phases. It was observed that the number of ridges in ...

      Read Full Article
    13. Morphometric parameters of the optic disk in normal and glaucomatous eyes based on time-domain optical coherence tomography image analysis

      Morphometric parameters of the optic disk in normal and glaucomatous eyes based on time-domain optical coherence tomography image analysis

      Background and objective Assessment of optic disk morphology is essential in diagnosis and management of visual impairment. The aim of this study was to evaluate associations between optic disk morphometric parameters, i.e., size and shape, and age, gender, and ocular axial length in normal and glaucomatous eyes based on time-domain optical coherence tomography image analysis. Materials and methods It was a case–control study of 998 normal and 394 eyes with primary open angle glaucoma that underwent ophthalmological investigation and time-domain optical coherence topography scanning. Areas and shapes of the disk, cup, and neuroretinal rim were analyzed. Results The ...

      Read Full Article
    14. Comparison of macular choroidal thickness in patients with pseudoexfoliation syndrome to normal control subjects with enhanced-depth SD-OCT imaging

      Comparison of macular choroidal thickness in patients with pseudoexfoliation syndrome to normal control subjects with enhanced-depth SD-OCT imaging

      Purpose To test the hypothesis that macular choroidal thickness is lower in patients with pseudoexfoliation syndrome (PXS) as compared to healthy control subjects. Methods In this cross-sectional, observational study, 38 non-glaucomatous PXS subjects and 37 healthy volunteers were enrolled in a tertiary care Glaucoma Clinic. The macular region was scanned with the enhanced depth imaging (EDI) protocol of a spectral domain optical coherence tomography (SD-OCT) device (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany). Macular choroidal thickness and volumes were compared in nine sectors of the Early Treatment Diabetic Retinopathy Study (ETDRS) layout profile across the central 3.45 mm zone after ...

      Read Full Article
    15. Clinical and morphological manifestations of aniridia-associated keratopathy on anterior segment optical coherence tomography and in vivo confocal microscopy

      Clinical and morphological manifestations of aniridia-associated keratopathy on anterior segment optical coherence tomography and in vivo confocal microscopy

      Purpose The study aimed to evaluate clinical and morphological changes in the limbal palisades of Vogt (POV) at different stages of aniridia-associated keratopathy (AAK) and to assess possible utility of anterior segment optical coherence tomography (AS-OCT) for the visualization of limbal progenitor structures as it correlates to laser scanning confocal microscopy (LSCM) data. Methods The study involved 32 patients (59 eyes) with congenital aniridia. AAK stage was defined based on biomicroscopy. Assessment of limbal zone and detection of POVs in identical areas was performed by LSCM (HRT3) and AS-OCT (RTVue XR Avanti) using 3D Cornea (En Face mode) and Cornea ...

      Read Full Article
    16. A framework for computational fluid dynamic analyses of patient-specific stented coronary arteries from optical coherence tomography images

      A framework for computational fluid dynamic analyses of patient-specific stented coronary arteries from optical coherence tomography images

      The clinical challenge of percutaneous coronary interventions (PCI) is highly dependent on the recognition of the coronary anatomy of each individual. The classic imaging modality used for PCI is angiography, but advanced imaging techniques that are routinely performed during PCI, like optical coherence tomography (OCT), may provide detailed knowledge of the pre-intervention vessel anatomy as well as the post-procedural assessment of the specific stent-to-vessel interactions. Computational fluid dynamics (CFD) is an emerging investigational tool in the setting of optimization of PCI results. In this study, an OCT-based reconstruction method was developed for the execution of CFD simulations of patient-specific coronary ...

      Read Full Article
    17. Uncovered Culprit Plaque Ruptures in Patients With ST-Segment Elevation Myocardial Infarction Assessed by Optical Coherence Tomography and Intravascular Ultrasound With iMap

      Uncovered Culprit Plaque Ruptures in Patients With ST-Segment Elevation Myocardial Infarction Assessed by Optical Coherence Tomography and Intravascular Ultrasound With iMap

      Objectives This study assessed the incidence and course of healing of uncovered plaque ruptures (PR) following primary percutaneous coronary intervention. Background The infarct-related occlusion is frequently located at the lesion site with maximum thrombus burden, whereas the culprit PR may be situated more proximally or distally. Methods Uncovered PR in segments adjacent to the stent were identified by optical coherence tomography and intravascular ultrasound using iMap (Boston Scientific, Marlborough, Massachusetts) within 48 h and after 12 months. The percentages of necrotic core, fibrotic tissue, lipid tissue, and calcific tissue were determined. Results Eleven uncovered PR were found in 10 of ...

      Read Full Article
    18. Combination of anterior segment optical coherence tomography modalities to improve accuracy of rectus muscle insertion location - ScienceDirect

      Combination of anterior segment optical coherence tomography modalities to improve accuracy of rectus muscle insertion location - ScienceDirect

      Anterior segment optical coherence tomography (AS-OCT) is useful for locating the extraocular muscle insertion prior to strabismus surgery; however, its accuracy decreases in reoperations. This masked retrospective study investigated whether a combination of AS-OCT modalities improves accuracy. The distance between the corneoscleral limbus and extraocular muscle insertion was measured with AS-OCT, first using the standard grayscale modality alone and then refined with the color modality. The AS-OCT measurement was considered accurate when within 1.00 mm of the intraoperative caliper measurement. A total of 139 AS-OCT images were analyzed from 74 patients (mean age, 52 years), including 60 medial rectus ...

      Read Full Article
    19. SYNTAX Score, and Pre- and Post-Stent Optical Coherence Tomography Findings in the Left Anterior Descending Coronary Artery in Patients with Stable Angina Pectoris

      SYNTAX Score, and Pre- and Post-Stent Optical Coherence Tomography Findings in the Left Anterior Descending Coronary Artery in Patients with Stable Angina Pectoris

      SYNTAX score (SS) has been reported to be an independent predictor of future cardiac events including target lesion revascularization (TLR). The aim of this study was to assess the relationship between SS and plaque characteristics and post-stent vascular response using optical coherence tomography (OCT) in coronary artery tree and left anterior descending artery (LAD) in patients with stable angina. A total of 179 lesions among 165 patients, including 100 lesions in LAD, were analyzed. Patients were stratified into tertiles. In pre-PCI analysis of whole coronary tree and LAD, lesions of the 3 rd tertile had the highest prevalence of lipid ...

      Read Full Article
    1-24 of 715 1 2 3 4 ... 28 29 30 »
  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