1. All Articles

    25-48 of 22003 « 1 2 3 4 5 ... 915 916 917 »
    1. Pharmaceutical film coating catalogue for spectral-domain optical coherence tomography

      Pharmaceutical film coating catalogue for spectral-domain optical coherence tomography

      Optical coherence tomography (OCT) has recently been demonstrated to measure the film coating thickness of pharmaceutical tablets and pellets directly. The results enable the analysis of inter- and intra-tablet coating variability at an off-line and in-line setting. To date, only a few coating formulations have been tried and there is very little information on the applicability of OCT to other coatings. As it is well documented that optical methods including OCT are prone to scattering leading to limited penetration, some pharmaceutical coatings may not be measurable altogether. This study presents OCT measurements of 22 different common coatings for the assessment ...

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    2. Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Purpose : To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA). Methods : Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated. Results : Forty subjects were enrolled and the median (range) age of the ...

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    3. Objective Quantification of Anterior Chamber Inflammation

      Objective Quantification of Anterior Chamber Inflammation

      Purpose To assess the ability of swept-source (SS) optical coherence tomography (OCT) of the anterior segment (AS) to measure anterior chamber (AC) inflammation (both flare and cells) objectively. To compare OCT-derived inflammatory indices with standard techniques. Design Prospective evaluation of a diagnostic test. Participants Patients diagnosed with anterior uveitis (active or inactive) and controls. Methods Participants underwent an AC inflammation evaluation including: clinical cell and flare grading and laser flare photometry (LFP). Uveitis patients were divided into active or inactive uveitis status according to clinical grading. Anterior segment SS-OCT scans were obtained for each participant. Tomographic images were analyzed to ...

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    4. Introduction to the feature issue on the 25 year anniversary of optical coherence tomography

      Introduction to the feature issue on the 25 year anniversary of optical coherence tomography

      This feature issue commemorates the approximately 25 year history of Optical Coherence Tomography (OCT), one of the most successful biophotonic technologies. While OCT has technological origins traceable to ultrafast laser development and fiber optic system test instrumentation of the 1980’s, innovations in low coherence interferometry for optical ranging and imaging for biomedical applications in the U.S., Europe and Japan by the early 1990’s led to coinage of the now widely known term OCT in 1991 [1]. As discussed in the following cited Invited Review and Invited Research articles in this issue, remarkable strides have since been made ...

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    5. Integrated optical system and components utilizing tunable optical sources and coherent detection and phased array for imaging, ranging, sensing, communications and other applications

      Integrated optical system and components utilizing tunable optical sources and coherent detection and phased array for imaging, ranging, sensing, communications and other applications

      An integrated optical system includes a photonic integrated circuit (PIC) having a frequency tunable optical source, a coherent optical receiver, and an optical phased array for coupling light to/from a sample. The integrated optical system is configured such that when the optical source is tuned in optical frequency the receiver produces electrical signals that are processed to produce optical profile information about the sample

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      Mentions: Eric A. Swanson
    6. Speckle-modulating optical coherence tomography in living mice and humans

      Speckle-modulating optical coherence tomography in living mice and humans

      Optical coherence tomography (OCT) is a powerful biomedical imaging technology that relies on the coherent detection of backscattered light to image tissue morphology in vivo . As a consequence, OCT is susceptible to coherent noise (speckle noise), which imposes significant limitations on its diagnostic capabilities. Here we show speckle-modulating OCT (SM-OCT), a method based purely on light manipulation that virtually eliminates speckle noise originating from a sample. SM-OCT accomplishes this by creating and averaging an unlimited number of scans with uncorrelated speckle patterns without compromising spatial resolution. Using SM-OCT, we reveal small structures in the tissues of living animals, such as ...

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    7. Quantitative analysis of retinal layers on three-dimensional spectral-domain optical coherence tomography for pituitary adenoma

      Quantitative analysis of retinal layers on three-dimensional spectral-domain optical coherence tomography for pituitary adenoma

      Purpose To quantitatively investigate the characteristics of eyes with pituitary adenoma presented by three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) using three common indices, including thickness, optical intensity ratio, and optical intensity attenuation coefficient (OIAC). Methods The SD-OCT database of 38 patients with pituitary adenoma and 39 normal controls were included in the study. Quadrantal and average measurements of thickness, optical intensity ratio, and OIAC were calculated for macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL) combined with inner plexiform layer (IPL) (GCIPL) and/or the collective ganglion cell complex (GCC). The parameters of patients and controls were ...

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    8. Anterior lens capsule and epithelium thickness measurements using spectral-domain optical coherence tomography

      Anterior lens capsule and epithelium thickness measurements using spectral-domain optical coherence tomography

      Background To investigate the anterior lens capsule and epithelium thickness (defined as anterior lens capsular complex: ALCC) in normal Chinese subjects using spectral-domian optical coherence tomography (SD-OCT) and examine the factors that may influence the ALCC, such as age, gender, pupil diameter (PD) and signal strength index (SSI). Methods A prospective observational case series. One-hundred-thirty-four normal subjects (134 eyes) were included. The ALCCs were determined manually via SD-OCT. Using the pupil center as a reference position, the central ALCC (CALCC), nasal 1-mm ALCC (NALCC), temporal 1-mm ALCC (TALCC) and PD were measured manually. Results The mean CALCC, NALCC and TALCC ...

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    9. Temporal evolution of low-coherence reflectrometry signals in photoacoustic remote sensing microscopy

      Temporal evolution of low-coherence reflectrometry signals in photoacoustic remote sensing microscopy

      Recently, a new noncontact reflection-mode imaging modality called photoacoustic remote sensing (PARS) microscopy was introduced providing optical absorption contrast. Unlike previous modalities, which rely on interferometric detection of a probe beam to measure surface oscillations, the PARS technique detects photoacoustic initial pressures induced by a pulsed laser at their origin by monitoring intensity modulations of a reflected probe beam. In this paper, a model describing the temporal evolution from a finite excitation pulse is developed with consideration given to the coherence length of the interrogation beam. Analytical models are compared with approximations, finite-difference time-domain (FDTD) simulations, and experiments with good ...

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    10. Catheter-based anatomic and functional assessment of coronary arteries in anomalous aortic origin of a coronary artery, myocardial bridges and Kawasaki disease

      Catheter-based anatomic and functional assessment of coronary arteries in anomalous aortic origin of a coronary artery, myocardial bridges and Kawasaki disease

      Most diagnostic testing in patients with anomalous aortic origins of coronary arteries, myocardial bridges, and coronary artery changes after Kawasaki disease are performed with the use of noninvasive techniques. In some cases, however, further diagnostic information is needed to guide the clinician in treating these patients. In such instances, cardiac catheterization with invasive anatomic and functional testing is an invaluable tool. Moreover, interventional treatment in the cardiac catheterization laboratory may be performed in a small subset of these patients. As the diagnosis of these conditions is now becoming more common, it is important for pediatric interventional cardiologists to be familiar ...

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    11. Universal in vivo Textural Model for Human Skin based on Optical Coherence Tomograms

      Universal in vivo Textural Model for Human Skin based on Optical Coherence Tomograms

      Currently, diagnosis of skin diseases is based primarily on visual pattern recognition skills and expertise of the physician observing the lesion. Even though dermatologists are trained to recognize patterns of morphology, it is still a subjective visual assessment. Tools for automated pattern recognition can provide objective information to support clinical decision-making. Noninvasive skin imaging techniques provide complementary information to the clinician. In recent years, optical coherence tomography has become a powerful skin imaging technique. According to specific functional needs, skin architecture varies across different parts of the body, as do the textural characteristics in OCT images. There is, therefore, a ...

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    12. Optical Coherence Tomography Technology and Quality Improvement Methods for Optical Coherence Tomography Images of Skin: A Short Review

      Optical Coherence Tomography Technology and Quality Improvement Methods for Optical Coherence Tomography Images of Skin: A Short Review

      Optical coherence tomography (OCT) delivers 3-dimensional images of tissue microstructures. Although OCT imaging offers a promising high-resolution method, OCT images experience some artifacts that lead to misapprehension of tissue structures. Speckle, intensity decay, and blurring are 3 major artifacts in OCT images. Speckle is due to the low coherent light source used in the configuration of OCT. Intensity decay is a deterioration of light with respect to depth, and blurring is the consequence of deficiencies of optical components. In this short review, we summarize some of the image enhancement algorithms for OCT images which address the above mentioned artifacts.

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    13. High Throughput Photonic Time Stretch Optical Coherence Tomography with Data Compression

      High Throughput Photonic Time Stretch Optical Coherence Tomography with Data Compression

      Photonic time stretch enables real time high throughput optical coherence tomography (OCT), but with massive data volume being a real challenge. In this paper, data compression in high throughput optical time stretch OCT has been explored and experimentally demonstrated. This is made possible by exploiting spectral sparsity of encoded optical pulse spectrum based on compressive sensing (CS) approach. Both randomization and integration have been implemented in the optical domain avoiding electronic bottleneck. Data compression ratio of 66% has been achieved in high throughput OCT measurements with 1.51 MHz axial scan rate using greatly reduced data sampling rate of 50 ...

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    14. Morphological and pharmacological determinants of peri-procedural myocardial infarction following elective stent implantation: Optical coherence tomography sub-analysis of the PRASFIT-Elective study

      Morphological and pharmacological determinants of peri-procedural myocardial infarction following elective stent implantation: Optical coherence tomography sub-analysis of the PRASFIT-Elective study

      Background Previous studies have suggested that peri-procedural myocardial infarction (PMI) following percutaneous coronary intervention (PCI) is associated with adverse short- and long-term outcomes, and several morphological predictors of PMI have been studied. However, the determinants of PMI under novel anti-platelet therapy are not fully elucidated. Methods and results PRASFIT-Elective is a multicenter, parallel-group study of PCI patients in non-acute settings receiving either prasugrel or clopidogrel in addition to aspirin. Among 742 study patients, 94 (116 lesions) underwent optical coherence tomography (OCT) to evaluate the area of intra-stent tissue (IST, which comprises tissue protrusion and thrombus) after stenting in addition to ...

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    15. Rapid ex vivo examination of Mohs specimens using optical coherence tomography

      Rapid ex vivo examination of Mohs specimens using optical coherence tomography

      Background Mohs micrographic surgery (MMS) is an effective treatment for certain non-melanoma skin cancers. Optical coherence tomography (OCT) is a biomedical imaging modality that permits high-resolution imaging of the epidermis and dermis with the potential to detect both healthy tissue and tumour. OCT may also provide a means of detecting and differentiating between the various histological subtypes of basal cell carcinomas (BCC) in vivo . Objective : The aim of this prospective ex vivo study was to evaluate the efficacy of OCT in recognising healthy and pathological margins of excised BCC lesions and detecting different BCC subtypes. Methods Seventy-three subjects with biopsy-proven ...

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    16. Beth Israel Deaconess Medical Center Receives NIH Grant for In Vivo Optical Detection of Dysplasia in Esophagus

      Beth Israel Deaconess Medical Center Receives  NIH Grant for In Vivo Optical Detection of Dysplasia in Esophagus

      Beth Israel Deaconess Medical Center Receives a 2017 NIH Grant for $598,587 for In Vivo Optical Detection of Dysplasia in Esophagus. The principal investigator is Lev Perelman. The program began in 2005 and ends in 2020. Below is a summary of the proposed work. Esophageal adenocarcinoma is the most common esophageal malignancy in Western world and the malignancy that is rising the fastest in the United States – approximately 7% per year over the past 30 years. It has very poor prognosis with less than 15% of patients alive 5 years after diagnosis. Worldwide, 482,300 new esophageal cancer cases ...

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    17. Persistent Placoid Maculopathy Treatment Response Imaged With OCT Angiography

      Persistent Placoid Maculopathy Treatment Response Imaged With OCT Angiography

      A 70-year-old Caucasian gentleman presented with decreased vision in the left eye and a subtle whitish macular plaque in the left eye and pigment mottling bilaterally. Indocyanine green angiography (ICGA) and optical coherence tomography angiography (OCTA) revealed left macular hypoperfusion. Systemic evaluation was negative for infectious or inflammatory disorder. A diagnosis of persistent placoid maculopathy was made and systemic immunosuppression was initiated. A marked improvement in macular perfusion was noted on ICGA and OCTA following 1 week of immunosuppression, providing additional evidence of an inflammatory rather than ischemic etiology.

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    18. Evaluation of optical coherence tomography angiographic findings in Alzheimer’s type dementia

      Evaluation of optical coherence tomography angiographic findings in Alzheimer’s type dementia

      Background/Aims To identify the retinal vascular pathologies in patients with Alzheimer’s type dementia (ATD) through optical coherence tomography angiography (OCTA) imaging. Methods Our study included 26 patients in the patient group, and age-matched and sex-matched 26 subjects in the control group. A detailed ophthalmological and neurological examination was performed for all subjects included in the study. The retinal, choroidal vascular structures and choroidal thickness (CT) of all subjects were analysed in a detailed way with a commercial spectral domain OCTA. Moreover, all participants underwent detailed neurological examination including Mini Mental State Examination (MMSE) test to evaluate cognitive function ...

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    19. Analysis of neointima development in flow diverters using optical coherence tomography imaging

      Analysis of neointima development in flow diverters using optical coherence tomography imaging

      Background Flow diverters are used for the treatment of intracranial aneurysms. Surface modification may decrease the thrombogenicity of flow diverters but the details are unknown. Optical coherence tomography (OCT) is an intravascular imaging test with high resolution which identifies neointimal growth over stents. We compared the development of neointima in a flow diverter and stents with and without surface modification in a swine model. Methods In this study we implanted four devices (two in each carotid artery) in four pigs. The devices used were the Pipeline Flex embolization device (PED Flex, n=6), PED with Shield technology (PED Shield, n ...

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    20. Features of optical coherence tomography predictive of choroidal neovascularisation treatment response in pathological myopia in association with fluorescein angiography

      Features of optical coherence tomography predictive of choroidal neovascularisation treatment response in pathological myopia in association with fluorescein angiography

      ackground/Aims The aim of this study was to evaluate the usefulness of several optical coherence tomography (OCT) findings to estimate choroidal neovascularisation (CNV) activity in pathological myopia using fluorescein angiography (FA) as a reference. Methods This was a single-centre, retrospective study. The medical records of patients with active myopic CNV who received intravitreal bevacizumab treatment were reviewed. Parameters to monitor CNV activity were morphological features of CNV on OCT, such as CNV height, central foveal thickness, intraretinal cysts, subretinal fluid, fuzziness of the CNV border, CNV network area on FA, and haemorrhage or exudation on fundus photo. Results There ...

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    21. A new technique for lipid core plaque detection by optical coherence tomography for prevention of peri-procedural myocardial infarction: A case report

      A new technique for lipid core plaque detection by optical coherence tomography for prevention of peri-procedural myocardial infarction: A case report

      Rationale: Percutaneous coronary intervention (PCI) provides effective revascularization of atherosclerotic coronary arteries but the invasive nature of treatment can result in complications. Patient concerns: A 53-year old man underwent coronary angiography due to chest pain with minimal ST-segment elevation in the inferior leads of the electrocardiogram. Diagnosis: We proceeded directly to coronary angiography and delineated a moderate stenosis with haziness in the mid right coronary artery (RCA). Interventions: Expert analysis of the pre-intervention OCT imaging demonstrated a large lipid core plaque (LCP), upstream of the culprit site, with minimal thrombus burden. Subsequent implantation of a bioresorbable vascular scaffold, protected with ...

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    25-48 of 22003 « 1 2 3 4 5 ... 915 916 917 »
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