1. 1-24 of 393 1 2 3 4 ... 15 16 17 »
    1. Comparative analysis of corneal measurements obtained from a Scheimpflug camera and an integrated Placido-optical coherence tomography device in normal and keratoconic eyes

      Comparative analysis of corneal measurements obtained from a Scheimpflug camera and an integrated Placido-optical coherence tomography device in normal and keratoconic eyes

      Purpose To assess the agreement between a Scheimpflug camera (Pentacam) and a combined Placido-optical coherence tomography device (Visante OMNI) in measuring corneal curvature, thickness and elevation values in normal and keratoconic eyes. Methods Corneal measurements of 110 normal eyes (one eye per subject) and 70 keratoconic eyes were obtained from both devices and compared. Agreement was determined using the Bland–Altman analysis 95% limits of agreement (LoA). Results The Pentacam measured significantly greater keratometry readings in the flattest (K1) and steepest meridians (K2) in normal and keratoconic eyes. The 95% LoA in normal eyes were −0.32 to 0.59 ...

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    2. Multimodality imaging of attenuated plaque using grayscale and virtual histology intravascular ultrasound and optical coherent tomography

      Multimodality imaging of attenuated plaque using grayscale and virtual histology intravascular ultrasound and optical coherent tomography

      Background Although attenuated plaque is a marker for plaque vulnerability, the quantification and its implication have not been known. Methods Multimodality pre-procedural imaging using grayscale intravascular ultrasound (IVUS), virtual histology-IVUS (VH-IVUS) and optical coherence tomography (OCT) were performed in 115 coronary lesions with diameter stenosis (DS) >30% and plaque burden ≥50% and compared the diagnostic accuracies for detecting thin-cap fibroatheromas (TCFA). Results A maximal arc of attenuation (40MHz IVUS) ≥29.0° was the cut-off for predicting VH-TCFA (sensitivity 74%, specificity 66%); and OCT-TCFA (sensitivity 89%, specificity 64%), while a maximal arc attenuation≥29.0° (20MHz IVUS) showed a poor sensitivity ...

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    3. Clinical assessment of non carious cervical lesion using swept-source optical coherence tomography

      Clinical assessment of non carious cervical lesion using swept-source optical coherence tomography

      ( A ) We determined the attenuation coeffcient (μ t ) threshold of SS-OCT signal for the detection of demineralization (1.21) from in vitro study. DEM: demineralized dentin, sound: sound dentin. ( B ) Using the μ t threshold, we observed NCCLs in vivo to detect the demineralization in cervical dentin. SS-OCT scanning was performed along the red line. ( C ) SS-OCT image obtained along the red line in B. In SS-OCT, brightness of dentin beneath the NCCL was increased (arrow) compared with intact zone. The cervical dentin was slightly demineralized (μ t : 1.25). e: enamel, d: dentin, g: gingiva. Non-carious cervical lesions (NCCLs) involve various forms ...

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    4. In vivo molecular mapping of the tumor microenvironment in an azoxymethane-treated mouse model of colon carcinogenesis

      In vivo molecular mapping of the tumor microenvironment in an azoxymethane-treated mouse model of colon carcinogenesis

      Background and Objective Development of miniaturized imaging systems with molecular probes enables examination of molecular changes leading to initiation and progression of colorectal cancer in an azoxymethane (AOM)-induced mouse model of the disease. Through improved and novel studies of animal disease models, more effective diagnostic and treatment strategies may be developed for clinical translation. We introduce use of a miniaturized multimodal endoscope with lavage-delivered fluorescent probes to examine dynamic microenvironment changes in an AOM-treated mouse model. Study Design/Materials and Methods The endoscope is equipped with optical coherence tomography (OCT) and laser induced fluorescence (LIF) imaging modalities. It is ...

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    5. Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Purpose To assess the effect of media opacities on thickness measurements of the peripapillary retinal nerve fibre layer (pRNFL) and macular inner retinal layer (mIRL) performed with spectral-domain optical coherence tomography (SD-OCT) using a set of filters with known optical density. Methods Spectral-domain optical coherence tomography volume scans of the optic disc and the macular area were performed in 18 healthy volunteers, using Topcon-3DOCT-1000 Mark II. A set of five filters with optical density ranging from 0.04 to 0.69 was used. The correlation was calculated between the percentage change in thickness measurements (%ΔpRNFL and %ΔmIRL) and the change ...

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    6. Chemical Strategies for the Development of Multimodal Imaging Probes Using Nanoparticles (Book Chapter)

      Chemical Strategies for the Development of Multimodal Imaging Probes Using Nanoparticles (Book Chapter)

      This chapter focuses on the most recently reported nanoparticle agents that have been demonstrated in vivo . It describes the general methods of chemical conjugations, silanisation, and electrostatic adsorption. The chapter examines the recent use of nanoparticles that incorporate a fluorescent dye and a magnetic nanoparticle together. The combination of near-infrared (NIR) and magnetic resonance imaging (MRI) modalities and in vivo characterisation has been executed in two ways: attaching an organic NIR dye to a superparamagnetic iron oxide nanoparticle (SPION); and combining SPIONs with a materials-based NIR fluorescent species such as a quantum dot or multilayered gold/silica nanoparticles. Upconversion luminescence ...

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    7. Dual optical modality endoscopic imaging of cancer development in the mouse colon

      Dual optical modality endoscopic imaging of cancer development in the mouse colon

      Background and Objective We utilize a miniature, dual-modality endoscope that combines fluorescence-based surface magnifying chromoendoscopy (SMC) and optical coherence tomography (OCT) to follow the anatomical changes that occur during adenoma development in the mouse colon. Materials and Methods Twenty-five mice were treated with the carcinogen azoxymethane (AOM) to induce tumor development in the distal colon, or were treated with saline as control, and were imaged over six months. OCT detects adenoma number with high sensitivity and specificity and can measure lesion size. In methylene blue-lavaged colons, SMC detects changes in the colonic crypts. SMC images of control mouse colons exhibit ...

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    8. Cross-evaluation of optimal glycerol concentration to enhance optical tissue clearing efficacy

      Cross-evaluation of optimal glycerol concentration to enhance optical tissue clearing efficacy

      Background/aims The efficacy of light therapeutic and diagnostic applications can be enhanced by employing optical tissue clearing (OTC) agents to minimize light scattering in tissue. This study aimed to investigate the optimal concentration of glycerol, so that it can be efficiently used as an OTC agent in dermatology. Methods Glycerol was topically applied to avoid the possibility of edema that could be caused by dermal injection. The efficacy of glycerol was quantitatively evaluated for various concentrations using optical coherence tomography (OCT) to evaluate light scattering and ultrasound imaging modality to evaluate collagen dissociation. Results The intensity in the OCT ...

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    9. Optical coherence elastography for tissue characterization: a review

      Optical coherence elastography for tissue characterization: a review

      Optical coherence elastography (OCE) represents the frontier of optical elasticity imaging techniques and focuses on the micro-scale assessment of tissue biomechanics in 3D that is hard to achieve with traditional elastographic methods. Benefit from the advancement of optical coherence tomography, and driven by the increasing requirements in nondestructive biomechanical characterization, this emerging technique recently has experienced a rapid development. In this paper, we start with the description of the mechanical contrast that has been employed by OCE and review the state-of-the-art techniques based on the reported applications and discuss the current technical challenges, emphasizing the unique role of OCE in ...

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    10. Combining region-based and imprecise boundary-based cues for interactive medical image segmentation

      Combining region-based and imprecise boundary-based cues for interactive medical image segmentation

      In this paper, we present an approach combining both region selection and user point selection for user assisted segmentation, as either an enclosed object or an open curve, and investigate the method of image segmentation in specific medical applications (user assisted segmentation of the media adventitia border in IVUS images, and lumen border in OCT images), and then demonstrate the method with generic images to show how it could be utilised in other types of medical image, and is not limited to the applications described.. The proposed method combines point based soft constraint on object boundary and stroke based regional ...

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    11. Real-time, noninvasive optical coherence tomography of cross-sectional living cell-sheets in vitro and in vivo

      Real-time, noninvasive optical coherence tomography of cross-sectional living cell-sheets in vitro and in vivo

      Cell sheet technology has a history of application in regenerating various tissues, having successfully completed several clinical trials using autologous cell sheets. Tomographic analysis of living cell sheets is an important tool in the field of cell sheet-based regenerative medicine and tissue engineering to analyze the inner structure of layered living cells. Optical coherence tomography (OCT) is commonly used in ophthalmology to noninvasively analyze cross-sections of target tissues at high resolution. This study used OCT to conduct real-time, noninvasive analysis of living cell sheet cross sections. OCT showed the internal structure of cell sheets in tomographic images synthesized with backscatter ...

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    12. Macular parameters of Stratus optical coherence tomography for assessing glaucoma in high myopia

      Macular parameters of Stratus optical coherence tomography for assessing glaucoma in high myopia

      Background The aim was to assess the macular parameters of glaucoma in highly myopic subjects. Methods In a retrospective study, we enrolled 72 highly myopic eyes (spherical equivalent up to -6.00 D), of which 31 had early to moderate glaucoma and 41 formed a control group. The diagnosis of early to moderate glaucoma was based on glaucomatous visual-field defects with a mean deviation better than -12 dB. All patients underwent imaging with Stratus optical coherence tomography. We subsequently performed analysis for macular volume and thickness parameters between two groups. Results Using Stratus optical coherence tomography, we found significantly lower ...

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    13. An overview of optical coherence tomography for ovarian tissue imaging and characterization

      An overview of optical coherence tomography for ovarian tissue imaging and characterization

      Ovarian cancer has the lowest survival rate among all the gynecologic cancers because it is predominantly diagnosed at late stages due to the lack of reliable symptoms and efficacious screening techniques. Optical coherence tomography (OCT) is an emerging technique that provides high-resolution images of biological tissue in real time, and demonstrates great potential for imaging of ovarian tissue. In this article, we review OCT studies for visualization and diagnosis of human ovaries as well as quantitative extraction of ovarian tissue optical properties for classifying normal and malignant ovaries. OCT combined with other imaging modalities to further improve ovarian tissue diagnosis ...

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    14. Interocular symmetry of retinal nerve fibre layer thickness in healthy eyes: a spectral-domain optical coherence tomographic study

      Interocular symmetry of retinal nerve fibre layer thickness in healthy eyes: a spectral-domain optical coherence tomographic study

      Purpose This study was performed to investigate the interocular symmetry of peripapillary retinal nerve fibre layer (RNFL) thickness, as measured by Cirrus high-definition spectral-domain optical coherence tomography (OCT), in healthy eyes. A wide range of subject ages and refractive errors was examined. Methods The retinal nerve fibre layer thickness was measured in 1,234 healthy eyes from 617 subjects using OCT. Interocular differences (right eye minus left eye) in global area and quadrant nerve fibre layer thicknesses were measured. The effect of age and refractive error on interocular nerve fibre layer thickness difference was also examined. Results Means (and standard ...

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    15. The usefulness of multimodal imaging for differentiating pseudopapilloedema and true swelling of the optic nerve head: a review and case series

      The usefulness of multimodal imaging for differentiating pseudopapilloedema and true swelling of the optic nerve head: a review and case series

      Ophthalmic practitioners have to make a critical differential diagnosis in cases of an elevated optic nerve head. They have to discriminate between pseudopapilloedema (benign elevation of the optic nerve head) and true swelling of the optic nerve head. This decision has significant implications for appropriate patient management. Assessment of the optic disc prior to the advanced imaging techniques that are available today (particularly spectral domain optical coherence tomography and fundus autofluorescence), has mainly used diagnostic tools, such as funduscopy and retinal photography. As these traditional methods rely on the subjective assessment by the clinician, evaluation of the elevated optic nerve ...

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    16. Three-Dimensional High Definition-Optical Coherence Tomography Image Acquisition Procedure For Basal Cell Carcinoma

      Three-Dimensional High Definition-Optical Coherence Tomography Image Acquisition Procedure For Basal Cell Carcinoma

      We read with great interest the paper "Histopathological correlates of basal cell carcinoma in slice and en-face imaging modes of high-definition optical coherence tomography" by Gambichler et al. Optical Coherence Tomography (OCT) seems an interesting technology to study skin tumours. In particular it has been found helpful for basal cell carcinoma (BCC) diagnosis in several investigations. 

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    17. Coronary artery wall imaging

      Coronary artery wall imaging

      Like X-Ray contrast angiography, MR coronary angiograms show the vessel lumens rather than the vessels themselves. Consequently, outward remodeling of the vessel wall, which occurs in subclinical coronary disease before luminal narrowing, cannot be seen. The current gold standard for assessing the coronary vessel wall is intravascular ultrasound, and more recently, optical coherence tomography, both of which are invasive and use ionizing radiation. A noninvasive, low-risk technique for assessing the vessel wall would be beneficial to cardiologists interested in the early detection of preclinical disease and for the safe monitoring of the progression or regression of disease in longitudinal studies ...

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    18. Optical coherence tomography imaging of the patent ductus arteriosus: First known uses in congenital heart disease

      Optical coherence tomography imaging of the patent ductus arteriosus: First known uses in congenital heart disease

      Background: Angiography is used to assess ductal morphology and caliber during interventional closure of the ductus arteriosus. We are evaluating the use of optical coherence tomography (OCT) to evaluate ductal anatomy given the potential benefit of superior resolution and lower radiation. Methods: Standard angiograms were performed on two patients with patent ductus arteriosus prior to device occlusion. OCT was then used to obtain high-resolution three-dimensional vessel reconstructions. Devices were chosen based on angiographic measurements. Results: OCT resulted in excellent three-dimensional anatomic definition, with elliptical narrowest lumenal measurements of 2.2 x 3.1 mm and 1.6 x 2.3 ...

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    19. Senile scleral plaques imaged with enhanced depth optical coherence tomography

      Senile scleral plaques imaged with enhanced depth optical coherence tomography

      Purpose Senile scleral plaques (SSP) are sharply demarcated greyish areas located just anterior to the insertions of the horizontal rectus muscles and thus are frequently encountered during transscleral intravitreal injections. The aim of this study was to characterize SSP using enhanced depth imaging spectral domain anterior segment optical coherence tomography (OCT) in a cohort of patients attending intravitreal injection clinics. Methods Prospective cross-sectional study of 380 patients attending the clinic for intravitreal injections at the Department of Ophthalmology at the Bern University Hospital. Thirty-two patients with SSP were identified and the anatomical features were assessed using anterior segment OCT. Results ...

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    20. Novel optical coherence tomography classification of torpedo maculopathy

      Novel optical coherence tomography classification of torpedo maculopathy

      Background Torpedo maculopathy is a rare condition with a twofold clinical significance. Firstly, it is a differential of atypical congenital hypertrophy of the retinal pigment epithelium. Secondly, visual field loss has been reported. We demonstrate the spectrum of structural abnormality of torpedo maculopathy as seen on optical coherence tomography, and correlate this with age of presentation, fundus autofluorescence, retinal sensitivity loss and visual field abnormality. Design A retrospective, observational case series. Participants Five Australian patients seen between 2008 and 2013. Methods Fundus photography, optical coherence tomography, fundus autofluorescence and visual field analysis. One patient underwent fluorescein angiography. Main Outcome Measures ...

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    21. Endoscopy for diagnosis and treatment in esophageal cancers: high-technology assessment

      Endoscopy for diagnosis and treatment in esophageal cancers: high-technology assessment

      The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on the endoscopic tools to recognize squamous cell dysplasia; confocal laser endomicroscopy for Barrett's esophagus; confocal microscopy in the cancer patient; optical coherence tomography in the assessment of subsquamous Barrett's metaplasia; endoscopic mucosal resection for high-grade dysplasia in Barrett's esophagus; HALO in the treatment of squamous dysplasia; and the use of fluorescence in situ hybridization to detect dysplasia and adenocarcinoma in patients with Barrett's esophagus.

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    1-24 of 393 1 2 3 4 ... 15 16 17 »
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