1. 721-744 of 849 « 1 2 ... 28 29 30 31 32 33 34 35 36 »
    1. Effect of hydration on assessment of early enamel lesion using swept-source optical coherence tomography

      Effect of hydration on assessment of early enamel lesion using swept-source optical coherence tomography

      Establishing reproducible methodologies for assessment of early enamel lesions using optical coherence tomography (OCT) appears to be challenging. This in vitro study longitudinally evaluated the subsurface enamel lesion progression after 3, 9 and 15 days by cross-sectional scanning using 1310 nm centered swept-source OCT (SS-OCT) under hydrated and dry conditions. The positive difference between the depth-integrated OCT signals at dry and hydrated conditions were calculated and adopted as dehydration parameter (DH). A linear regression was found between DH and the square root of demineralization time (R2 = 0.99). Significant differences were found in DH between sound and demineralized enamel, and ...

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    2. Initial findings of impact of strut width on stent coverage and apposition of sirolimus-eluting stents assessed by optical coherence tomography

      Initial findings of impact of strut width on stent coverage and apposition of sirolimus-eluting stents assessed by optical coherence tomography

      Objectives: We investigate the influence of stent design on stent coverage at 6 to 9 months after sirolimus eluting stent (SES) implantation using optical coherence tomography (OCT). Background: Although some reports suggest that stent design may correlate with stent coverage of stent struts, there was few detailed data whether stent design impact on stent coverage in the same drug-eluting stent. Methods: A total of 21 SESs (15 patients), who had implanted 2.5, 2.75 and 3.0mm-stents, underwent OCT at 6 to 9 months after stent implantaiton. SES is constructed by two different strut width-components; narrow strut width parts ...

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    3. Retinal measurements using time domain OCT imaging before and after myopic Lasik

      Retinal measurements using time domain OCT imaging before and after myopic Lasik

      Purpose:  To compare retinal measurements obtained by time domain optical coherence tomography (OCT) devices before and after myopic laser in situ keratomileusis (Lasik) and to assess the interaction of Lasik and retinal structures as measured by time domain OCT. Methods:  Fifty-three patients randomly selected participated in the study. Only the right eye of each subject was included in the study. Comprehensive ophthalmic examinations including refraction examination, slit lamp examination, dilated fundus examination, corneal topography, corneal thickness, intraocular pressure, and retinal Stratus OCT scans were acquired for each patient before myopic Lasik and 3 months after surgery. Results:  Total macular volume ...

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    4. Imaging a spiral dissection of the superficial femoral artery in high resolution with optical coherence tomography—Seeing is believing

      Imaging a spiral dissection of the superficial femoral artery in high resolution with optical coherence tomography—Seeing is believing

      Optical coherence tomography (OCT) offers an alternative to intravascular ultrasound (IVUS) for endovascular imaging. Clinical and research applications for OCT have emerged in percutaneous coronary intervention (PCI), however, OCT has not found similar utility in peripheral arterial interventions. Early generation time-domain OCT systems required arterial occlusion to create the blood free environment needed for image acquisition and could not reliably scan vessel diameters encountered in the peripheral circulation. However, the frequency-domain OCT (FD-OCT) system currently FDA approved for use in the United States does not require arterial occlusion to generate images and permits a greater scan diameter allowing for exploratory ...

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    5. Four-dimensional imaging of murine subpleural alveoli using high-speed optical coherence tomography

      Four-dimensional imaging of murine subpleural alveoli using high-speed optical coherence tomography

      The investigation of lung dynamics on alveolar scale is crucial for the understanding and treatment of lung diseases, such as acute lung injury and ventilator induced lung injury, and to promote the development of protective ventilation strategies. One approach to this is the establishment of numerical simulations of lung tissue mechanics where detailed knowledge about three-dimensional alveolar structure changes during the ventilation cycle is required. We suggest four-dimensional optical coherence tomography (OCT) imaging as a promising modality for visualizing the structural dynamics of single alveoli in subpleural lung tissue with high temporal resolution using a mouse model. A high-speed OCT ...

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    6. Optical coherence tomography evaluation of drug-eluting stents: A systematic review

      Optical coherence tomography evaluation of drug-eluting stents: A systematic review

      Aims We performed a systematic review of studies reporting stent strut coverage and malapposition post implantation of different drug-eluting stent (DES), as assessed by optical coherence tomography (OCT). Methods A review of publications and online databases in May 2011 retrieved 33 published studies reporting stent strut coverage and malapposition post-DES implantation using OCT: 24 for sirolimus-eluting stents (SES), 13 for paclitaxel-eluting stents (PES), 10 for zotarolimus-eluting stents (ZES), and two for everolimus-eluting stents (EES). The follow-up duration ranged from 3 months to 4 years. Stent strut coverage and malapposition were compared between DES at various time intervals post implantation. Results ...

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    7. Comparison of optic disc parameters using spectral domain cirrus high-definition optical coherence tomography and confocal scanning laser ophthalmoscopy in normal eyes

      Comparison of optic disc parameters using spectral domain cirrus high-definition optical coherence tomography and confocal scanning laser ophthalmoscopy in normal eyes

      Purpose:  To compare Cirrus HD – optical coherence tomography (HD-OCT) with confocal scanning laser ophthalmoscopy (HRT 3) for analysis of optic disc parameters in healthy eyes. Methods:  In 126 subjects, cup volume (CV), vertical cup/disc ratio (CDR), neuroretinal rim area (NRA), cup area (CA) and optic disc area (ODA) were measured with the Cirrus HD-OCT and HRT 3. These optic disc parameters were chosen for statistical analysis because they can be analysed in both OCT and HRT 3 and they are widely used parameters for glaucoma assessment. Results:  Mean values and significances of paired t-tests for OCT and HRT were ...

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    8. Multimodal optical imaging with multiphoton microscopy and optical coherence tomography

      Multimodal optical imaging with multiphoton microscopy and optical coherence tomography

      Two types of combined multiphoton microscopy and optical coherence tomography (MPM/OCT) are compared for multimodal optical imaging. Single-scale multiphoton microscopy and optical coherence microscopy (MPM/OCM) is shown to acquire multiple contrasts from MPM and OCT simultaneously. Multi-scale MPM/OCT is shown to provide multiple field-of-views (FOVs), where OCT provides tissue level imaging and MPM provides cellular level imaging. In both types, the MPM includes two channels which are two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). Representative images using each system are demonstrated on biological specimens. A detailed comparison of the two types of MPM/OCT shows ...

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    9. Correlation between optic nerve head parameters and retinal nerve fibre layer thickness measured by spectral-domain optical coherence tomography in myopic eyes

      Correlation between optic nerve head parameters and retinal nerve fibre layer thickness measured by spectral-domain optical coherence tomography in myopic eyes

      Background:  To evaluate the correlation between optic nerve head (ONH) parameters and retinal nerve fibre layer (RNFL) thickness measured by Cirrus HD spectral-domain optical coherence tomography (OCT) in healthy myopic eyes. Design:  Cross-sectional study at the Armed Forces Capital Hospital, Korea. Participants:  One-hundred and sixty one right eyes from 161 healthy young myopic subjects. Methods:  ONH parameters and RNFL thickness were measured with the Cirrus HD-OCT. The distance between optic disc margin and scan circle (disc margin-to-scan distance) was measured on the Cirrus HD-OCT en-face ONH image with aid of National Institutes of Health ImageJ image-analysis software. Main Outcome Measures ...

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    10. Quantifying dental biofilm growth using cross-polarization optical coherence tomography

      Quantifying dental biofilm growth using cross-polarization optical coherence tomography

      Abstract Aims:  Quantifying the ex vivo growth of complex multi-species dental biofilms by cross-polarization 1310-nm optical coherence tomography system (CP-OCT) was investigated. Methods and Results:  Bacterial microcosms, which were derived from plaque samples of pediatric subjects, were incubated in a biofilm reactor system containing discs of different dental materials for 72 hours with daily sucrose pulsing (5x). CP-OCT analysis of biofilm mass was validated with crystal violet assays at various growth stages of these complex biofilms. CP-OCT was able to filter out the back-reflected signals of water layers in the hydrated biofilm and allowed for direct biofilm quantification. The overall ...

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    11. Impact of scanning density on spectral domain optical coherence tomography assessments in neovascular age-related macular degeneration

      Impact of scanning density on spectral domain optical coherence tomography assessments in neovascular age-related macular degeneration

      Purpose:  To determine the effect of optical coherence tomography (OCT) B-scan density on the qualitative assessment of neovascular age-related macular degeneration (AMD). Methods:  Data were collected from 59 patients imaged with Topcon 3D OCT-1000 (128 B-scans × 512 A-scans). Custom software was used to generate less dense subsets of scans: 1/16 (eight B-scans), 1/8 (16 B-scans), 1/4 (32 B-scans) and 1/2 (64 B-scans). At each B-scan density, scans were assessed for cystoid spaces, subretinal fluid (SRF), subretinal tissue (SRT) and pigment epithelium detachment (PED). For each sampling density, sensitivity, specificity and predictive values were calculated using the ...

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    12. Noninvasive cross-sectional imaging of incomplete crown fractures (cracks) using swept-source optical coherence tomography

      Noninvasive cross-sectional imaging of incomplete crown fractures (cracks) using swept-source optical coherence tomography

      Aim:  To investigate the ability of swept-source optical coherence tomography (SS-OCT) to detect incomplete crown fractures (cracks) in extracted teeth. Methodology:  Cracks were created by subjecting 30 porcine premolars to impaction by a steel rod plunging from the occlusal tip. SS-OCT images and stereomicroscopic photographs of the surface were acquired for each specimen before and after impaction. For evaluation, the focused light beam of SS-OCT was projected from 3 directions on the same plane: buccal or lingual, 45° to the mesial, and 45° to the distal. Histological sections were prepared after impaction, and length and width of cracks and lamellae ...

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    13. New developments in tools for periodontal diagnosis

      New developments in tools for periodontal diagnosis

      Objectives:  For decades there has been increasing focus on the development of clinically acceptable, more sensitive and specific methods for the accurate and non-invasive diagnosis and prognosis of periodontitis. There are several well-known inherent drawbacks to current clinical procedures. The purpose of this article is to summarise some of the newly emerging diagnostic approaches, namely: the ultrasonographic probe; cone-beam computed tomography; optical coherence tomography; optical spectroscopy, and proteome analysis. Results:  These novel diagnostic tools complement one another and, together with conventional clinical and radiographic examination, are likely to provide more accurate methods of diagnosing periodontitis. However, these techniques are yet ...

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    14. Impact of different stent alloys on human vascular response to everolimus-eluting stent. An optical coherence tomography study. The OCTEVEREST

      Impact of different stent alloys on human vascular response to everolimus-eluting stent. An optical coherence tomography study. The OCTEVEREST

      Background: New generation drug-eluting stents (DES) incorporate thinner struts and novel alloys to improve clinical performance. Nevertheless, the impact of novel stent materials and designs on human vascular response to DES remains elusive. We sought to evaluate the in-vivo coronary artery response to platinum-chromium (PtCr) versus cobalt-chromium (CoCr) stents featuring the same durable polymer and antiproliferative drug by optical coherence tomography (OCT). Methods and Results: A total of 42 patients with de novo lesions in native coronary vessels was treated with PtCr-everolimus eluting stent (EES) (n=21) or CoCr-EES (n=21). Angiography, intravascular ultrasound, and OCT were performed at the ...

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    15. Sensitivity and specificity of time-domain and spectral-domain optical coherence tomography in differentiating optic nerve head drusen and optic disc oedema

      Sensitivity and specificity of time-domain and spectral-domain optical coherence tomography in differentiating optic nerve head drusen and optic disc oedema

      Purpose:  To evaluate the efficacy of time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT) in differentiating between optic nerve head drusen (ONHD) and optic disc oedema (ODE). Methods:  We studied 66 patients with ONHD, 31 patients with ODE, and 70 controls using TD-OCT and SD-OCT. We analysed two aspects of the tomographic findings: (i) quantitative, through measurement of the retinal nerve fibre layer (RNFL) and papillary elevation; and (ii) qualitative, through assessment of the hyporeflective space, morphology of the internal contour, focal papillary mass and RNFL increases in seven contiguous clock hours. We evaluated the sensitivity, specificity ...

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    16. Comparison of optic nerve head parameters using Heidelberg retinal tomography 3 and spectral-domain optical coherence tomography

      Comparison of optic nerve head parameters using Heidelberg retinal tomography 3 and spectral-domain optical coherence tomography

      Background:  To assess the agreement between the Heidelberg Retina Tomograph (HRT) and Cirrus spectral-domain OCT (Cirrus HD-OCT) when measuring optic disc parameters. Design:   Prospective, cross-sectional study. Participants:  A total of 96 glaucoma patients and 21 normal subjects were analyzed. Methods:  Optic nerve head (ONH) measurements including disc area, rim area, cup-to-disc ratio, and cup volume were obtained using both the Cirrus HD-OCT and HRT 3. Main Outcome Measurements:   Bland-Altman plots were used to evaluate the agreement between each of the optic disc parameters. Results:  While Cirrus HD-OCT values were smaller than HRT 3 values for the disc and rim areas ...

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    17. Relationship between Stent Malapposition and Incomplete Neointimal Coverage after Drug-Eluting Stent Implantation

      Relationship between Stent Malapposition and Incomplete Neointimal Coverage after Drug-Eluting Stent Implantation

      Background: Using optical coherence tomography (OCT), we evaluated the relationship between malapposed and uncovered struts following implantation of drug-eluting stents (DESs). Methods: A total of 271 patients with 306 lesions who underwent DES implantation and follow-up OCT were included in the study. The lesions were grouped based on the presence of malapposition and then by the median value of the percentage of malapposed struts (1.3%) to produce 3 groups: lesions without malapposition (group I, n = 232) and those with percentage of malapposed struts

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    18. Integrated multimodal optical microscopy for structural and functional imaging of engineered and natural skin

      Integrated multimodal optical microscopy for structural and functional imaging of engineered and natural skin

      An integrated multimodal optical microscope is demonstrated for high-resolution, structural and functional imaging of engineered and natural skin. This microscope incorporates multiple imaging modalities including optical coherence (OCM), multi-photon (MPM), and fluorescence lifetime imaging microscopy (FLIM), enabling simultaneous visualization of multiple contrast sources and mechanisms from cells and tissues. Spatially co-registered OCM/MPM/FLIM images of multi-layered skin tissues are obtained, which are formed based on complementary information provided by different modalities, i.e., scattering information from OCM, molecular information from MPM, and functional cellular metabolism states from FLIM. Cellular structures in both the dermis and epidermis, especially different morphological ...

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    19. Influence of a pore-forming agent on swelling, network parameters, and permeability of poly(ethylene glycol)-crosslinked poly(methyl vinyl ether-co-maleic acid) hydrogels: Application in transdermal delivery systems

      Influence of a pore-forming agent on swelling, network parameters, and permeability of poly(ethylene glycol)-crosslinked poly(methyl vinyl ether-co-maleic acid) hydrogels: Application in transdermal delivery systems

      We characterized hydrogels, prepared from aqueous blends of poly(methyl vinyl ether-co-maleic acid) (PMVE/MA) and poly(ethylene glycol) (PEG 10,000 Daltons) containing a pore-forming agent (sodium bicarbonate, NaHCO3). Increase in NaHCO3 content increased the equilibrium water content (EWC) and average molecular weight between crosslinks (Mc) of hydrogels. For example, the %EWC was 731, 860, 1109, and 7536% and the Mc was 8.26, 31.64, 30.04, and 3010.00 × 105 g/mol for hydrogels prepared from aqueous blends containing 0, 1, 2, and 5% w/w of NaHCO3, respectively. Increase in NaHCO3 content also resulted in increased ...

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    20. Evolution of a juxtapapillary von Hippel–Lindau tumour examined by optical coherence tomography

      Evolution of a juxtapapillary von Hippel–Lindau tumour examined by optical coherence tomography

      Purpose:  The aim was to report the evolution of a case of von Hippel–Lindau (VHL) juxtapapillary retinal capillary haemangioblastoma (RCH) by optical coherence tomography (OCT3). Case report:  The progress of a 24-year-old man suffering from VHL disease with a juxtapapillary haemangioblastoma and a small peripheral lesion was followed for 26.4 months with fundus photographs and OCT of the optic nerve head using the optic nerve head rim volume, ranging from 1.106 to 1.895 mm3. Visual acuity remained 6/6 throughout. Conclusions:  OCT can be a useful tool in the follow up and decision-making of patients with ...

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    21. Prevalence of early and late stages of physiologic PVD in emmetropic elderly population - Schwab - 2011 - Acta Ophthalmologica - Wiley Online Library

      Prevalence of early and late stages of physiologic PVD in emmetropic elderly population - Schwab - 2011 - Acta Ophthalmologica - Wiley Online Library

      Purpose:  To investigate the early and late stages of posterior vitreous detachment (PVD) in the foveal area in correlation with age and gender. Methods:  Three hundred and thirty-five emmetropic eyes of 271 Caucasian patients (216 women/119 men) were examined by optical coherence tomography (OCT) and ultrasound (US). Eyes were classified into groups according to the patients age (up to 69.9; 70–74.9; 75–79.9; over 80 years) and to the clinical findings [Vitreous state: Detached in US; Detached in OCT; Foveal adhesion (FA); Attached vitreous]. Results:  The mean age was 76 ± 8 ranging from 44 to ...

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    22. Measurement of epithelial thickness within the oral cavity using optical coherence tomography

      Measurement of epithelial thickness within the oral cavity using optical coherence tomography

      Background The purpose of the present study was to determine normal values of epithelial thickness within the oral cavity by using optical coherence tomography (OCT). MethodsIn a total of 143 healthy test persons, epithelial thickness of the oral mucosa was determined with the help of OCT separately for each side at 7 different locations. Special attention was directed to those sites having the highest incidence for the development of dysplasias and carcinomas.ResultsThe epithelium demonstrated a varying thickness depending on its location within the oral cavity. The highest values were found in the region of the buccal mucosa (294 μm ...

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    23. Quantitative discrimination of NPC cell lines using optical coherence tomography

      Quantitative discrimination of NPC cell lines using optical coherence tomography

      We tried to explore the intrinsic differences in the optical properties of the four representative NPC cell lines on the models of radiobiology and metastasis by OCT. The scattering coefficients and anisotropies were extracted by fitting the average a-scan attenuation curves based on the multiple scatter effect. The values of scattering coefficients and anisotropy factors were 5.21 ± 0.11, 5.30 ± 0.09, 5.92 ± 0.21, 6.97 ± 0.22, and 0.892 ± 0.009, 0.886 ± 0.006, 0.884 ± 0.009, 0.86 ± 0.01 for CNE1, CNE2, 5-8F and 6-10B pellets (p < 0.05, P = 0.07 for CNE1 and CNE2), respectively. The results showed that the radiobiology and metastasis cell's model could be distinguished obviously; which implied that the corresponding types of NPC tissue might be potentially differentiated by OCT.

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    24. Evaluation of a posterior vitreous detachment: a comparison of biomicroscopy, B-scan ultrasonography and optical coherence tomography to surgical findings with chromodissection

      Evaluation of a posterior vitreous detachment: a comparison of biomicroscopy, B-scan ultrasonography and optical coherence tomography to surgical findings with chromodissection
      Purpose:  To find the most reliable and efficient noninvasive technique to clinically detect a posterior vitreous detachment. Methods:  In a prospective study of 30 eyes in 30 patients with macular pucker or macular hole formation, the posterior vitreous cortex was examined 1 day prior to a scheduled vitrectomy. Three independent investigators classified the posterior vitreous cortex of each eye as ‘attached’ or ‘detached’ via slit-lamp biomicroscopy (BM), 10-MHz B-scan ultrasonography (I³ Innovative Imaging Inc.), and optical coherence tomography [OCT III Stratus® (Carl Zeiss Meditec Inc.) and RTVue-100 OCT (Optovue Corp.)]. These preoperative findings were then compared during a triamcinolone acetonide-assisted ...
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