1. 745-768 of 889 « 1 2 ... 29 30 31 32 33 34 35 36 37 »
    1. Evaluation of long-term follow-up with neointimal coverage and stent apposition after sirolimus-eluting stent implantation by optical coherence tomography

      Evaluation of long-term follow-up with neointimal coverage and stent apposition after sirolimus-eluting stent implantation by optical coherence tomography

      Background Late stent thrombosis related to delayed endothelialization is a major concern after drug-eluting stent (DES) implantation. The long-term vascular response towards DES implantation remains unclear. Optical coherence tomography (OCT) is a high resolution imaging modality which provides new opportunities for evaluating neointimal coverage and stent strut apposition after stent implantation. Methods Fifty two patients who accepted 64 sirolimus-eluting stents (SESs, Cypher Select) were enrolled in the study. The OCT procedure was performed in 20 patients at 12 months (group 1), 17 patients at 24 months (group 2), and 15 patients at 48 months (group 3) after SESs implantation, respectively ...

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    2. Prognostic factors in vitrectomy for lamellar macular hole assessed by spectral-domain optical coherence tomography

      Prognostic factors in vitrectomy for lamellar macular hole assessed by spectral-domain optical coherence tomography

      Purpose:  To evaluate the association between the macular structure on spectral-domain optical coherence tomography (SD-CT) and visual outcome after vitrectomy for lamellar macular hole (LMH). Methods:  Best-corrected visual acuity (VA) and SD-OCT images of the macula were assessed before and after surgery in 30 eyes of 30 patients with a LMH. Preoperative VA and SD-OCT features were investigated as predictors of surgical outcome. Results:  Mean patient age was 65 years with female predominance (77%). Visual acuity improved in 19 eyes (63%) with an overall mean improvement of 1 Snellen line (from 20/65 to 20/50; p = 0.002) at ...

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    3. Use of a combined slit-lamp SD-OCT to obtain anterior and posterior segment images in selected animal species

      Use of a combined slit-lamp SD-OCT to obtain anterior and posterior segment images in selected animal species

      Objective  To obtain images of anterior and posterior segments of the eye using a slit-lamp (SL)/spectral domain (SD) optical coherence tomography (OCT) integrated system designed for the human eye, in the cat, dog, minipig and monkey. Animals studied  One healthy adult monkey, one healthy adult minipig, one healthy adult dog, one healthy adult cat, and three cats and four dogs affected by corneal or retinal diseases. Procedure  A SL SCAN-1 SD-OCT, which is a slit-lamp SL-D7 that contains an integrated OCT module and a fundus viewer, was used to generate OCT images (512–2048), while simultaneously taking ‘en-face’ slit-lamp ...

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    4. Iridocorneal angle measurements in mammalian species: normative data by optical coherence tomography

      Iridocorneal angle measurements in mammalian species: normative data by optical coherence tomography

      Objective  Gonioscopy provides limited quantitative information to compare the iridocorneal anatomy across different species. In addition, the anatomic relationships by histologic examination are altered during processing. As a result, the comparative anatomy of the iridocorneal angle across several mammalian species was evaluated by Optical Coherence Tomography (OCT). Methods  Cats, beagle dogs, minipigs, owl monkeys, cynomolgus monkeys, and rhesus monkeys (n = 6 or 7 per species) were evaluated. Imaging was performed using the OCT. The anterior chamber angle (ACA), angle opening distance (AOD), and the angle recess area (ARA) were evaluated. Results  AC angle: cat (63 ± 6°) > owl monkey (54 ± 4 ...

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    5. Correlation of structural RNFL parameters and functional measures using HRT3 and Spectralis SD-OCT at different levels of glaucoma severity

      Correlation of structural RNFL parameters and functional measures using HRT3 and Spectralis SD-OCT at different levels of glaucoma severity

      Background:  To compare the structure/function relationship in glaucoma cases at different levels of severity, and with different disc sizes, between the Heidelberg Retinal Tomography (HRT3) and Spectralis Spectral Domain Optical Coherence Tomography (SD-OCT). Design:   Retrospective study of glaucoma patients attending a Sydney-based private practice. Participants:   169 eyes of 169 patients, with a clinical diagnosis of glaucoma. Methods:   Patients were divided on visual field criteria into early (MD>-4dB), moderate (-4dB

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    6. Quantitative evaluation of anterior chamber parameters using anterior segment optical coherence tomography in primary angle closure mechanisms

      Quantitative evaluation of anterior chamber parameters using anterior segment optical coherence tomography in primary angle closure mechanisms

      Background:  To evaluate different mechanisms of primary angle closure (PAC) and to quantify anterior chamber (AC) parameters in these mechanisms using anterior segment optical coherence tomography (AS-OCT) in an Asian population. Design:  Hospital based cross sectional observational study. Participants:  Forty-eight consecutive patients with PAC and PAC glaucoma. Methods:   Patients underwent complete ophthalmic examination and imaging of nasal-temporal angles with AS-OCT. Images were categorized into 4 PAC mechanisms: pupil block (PB), plateau (PL) iris configuration, Thick peripheral iris roll (PIR) and exaggerated lens vault (LV). Parameters computed: AC depth central (ACDC), ACD1000 and ACD2000 (ACD at 1000µm and 2000µm anterior to ...

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    7. Assessment of accuracy and repeatability of anterior segment optical coherence tomography and reproducibility of measurements using a customised software program

      Assessment of accuracy and repeatability of anterior segment optical coherence tomography and reproducibility of measurements using a customised software program

      Purpose:  The aim was to study the reliability of measurements of the RTVue (Optovue, Fremont, CA, USA) anterior segment optical coherence tomographer (AS-OCT) and assess how results can be improved by analysing raw optical coherence tomography data with customised image analysis software and applying correction factors. Methods:  Five RTVue AS-OCT instruments (ver. 4.0) were assessed by imaging gauge blocks of three different lengths, single/stepped glass plate (microscope slides) and flat window glass to check for width, depth and linearity of the measurement scans. Five repeats per calibration tool were imaged and averaged. Raw data were exported and loaded ...

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    8. Test-retest variation in macular thickness measurements with the Heidelberg Retina Tomograph

      Test-retest variation in macular thickness measurements with the Heidelberg Retina Tomograph

      Purpose:  The aim was to evaluate the test-retest variation of macular thickness measurements using the Heidelberg Retina Tomograph (HRT3) Retina Module and compare it with the Stratus optical coherence tomography (OCT). As no normative data has been published for the HRT Retina Module, a secondary purpose was to obtain reference values for this technique. Methods:  Thirty healthy subjects and nine patients with macular oedema were examined. The healthy subjects underwent five examinations by two experienced examiners at two different occasions. The patients with maculopathy were examined twice by one examiner on one occasion. All measurements were made with both the ...

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    9. The diagnostic significance of Fourier-domain optical coherence tomography in Sjögren syndrome, aqueous tear deficiency and lipid tear deficiency patients

      The diagnostic significance of Fourier-domain optical coherence tomography in Sjögren syndrome, aqueous tear deficiency and lipid tear deficiency patients

      Purpose:  To determine the role of Fourier-domain optical coherence tomography (FD-OCT) in tear meniscus imaging and evaluate its diagnostic significance in Sjögren syndrome (SS), non-Sjögren’s aqueous tear deficiency (ATD) and lipid tear deficiency (LTD) patients. Methods:  Two hundred and thirty-six dry eye patients and 174 healthy controls were enrolled in this study. All subjects were grouped as follows: group A (ATD), group B (LTD), group C (SS) and group D (normal controls). All subjects underwent dry eye questionnaire, FD-OCT scanning, tear film break-up time (BUT), corneal fluorescence staining and Schirmer I test (SIT). Tear meniscus height (TMH), tear meniscus ...

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    10. Hybrid intravascular ultrasound and optical coherence tomography catheter for imaging of coronary atherosclerosis

      Hybrid intravascular ultrasound and optical coherence tomography catheter for imaging of coronary atherosclerosis

      Objective To demonstrate the feasibility of imaging human coronary atherosclerosis using a novel hybrid intravascular ultrasound (IVUS) and optical coherence tomography (OCT) imaging catheter. Background IVUS and OCT have synergistic advantages and recent studies involving both modalities suggest the use of a hybrid imaging catheter may offer improved guidance of coronary interventions and plaque characterization. Methods A 1.3 m custom hybrid IVUS-OCT imaging probe was built within a 4F catheter using a 42 MHz ultrasound transducer and an OCT imaging fiber. Coplanar images were simultaneously acquired ex vivo by both modalities in 31 arterial segments from 11 cadaveric human ...

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    11. Intra-operative tumour detection and staging in colorectal cancer surgery

      Intra-operative tumour detection and staging in colorectal cancer surgery

      External link. Please review our privacy policy . Aim:  Surgical resection for colorectal cancer involves segmental resection and regional lymphadenectomy. The appropriateness of this "one-size-fits-all" strategy is questioned as bowel cancer screening programmes result in a shift to earlier stage disease. Currently, the nodal status of a colorectal cancer can only be reliably determined by histopathological examination of the resected specimen. New methods of intra-operative staging are required to allow surgical resection to be tailored to the stage of the disease. Method:  A literature search was performed of Pubmed and Embase databases using the terms 'colon' OR 'colorectal' AND 'intra-operative detection ...

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    12. OCT in Coronary Bifurcations (Book Chapter)

      OCT in Coronary Bifurcations (Book Chapter)

      The geometric and anatomical complexity of bifurcations makes its systematic scientific approach very challenging. Optical coherence tomography (OCT) is able to depict accurately the plaque distribution around the bifurcation, to provide valuable information to tailor the procedure in each specific case, and to assess the result after stenting. Some guidelines are proposed for the systematic study of bifurcations with OCT, assessing the apposition, tissue coverage, the presence of overlap or multi-layer segments, the presence of non-apposed side-branch struts, the scaffolding of the carina and the shoulder, and the access to the side branch.

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    13. Morphology of basal cell carcinoma in high definition optical coherence tomography: en-face and slice imaging mode, and comparison with histology

      Morphology of basal cell carcinoma in high definition optical coherence tomography: en-face and slice imaging mode, and comparison with histology

      Background  Optical coherence tomography (OCT) allows real-time, in vivo examination of basal cell carcinoma (BCC). A new high definition OCT with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode offers additional information in the diagnosis of BCC and may potentially replace invasive diagnostic biopsies. Objectives  To define the characteristic morphologic features of BCC by using high definition optical coherence tomography (HD-OCT) compared to conventional histology. Methods  A total of 22 BCCs were examined preoperatively by HD-OCT in the en-face and slice imaging mode and characteristic features were evaluated in comparison to the histopathological findings ...

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    14. Accuracy of intraocular lens power calculation using partial coherence interferometry in patients with high myopia

      Accuracy of intraocular lens power calculation using partial coherence interferometry in patients with high myopia

      Purpose:  Ultrasound-A-scan-biometry intraocular lens power calculation for cataract surgery sometimes shows lack of accuracy in patients with high myopia. The purpose of this retrospective study was to assess the accuracy of lens power calculation with optical biometry using the Zeiss IOLMaster across a large range of myopia levels. Methods:  We included 37 consecutive, myopic eyes with an axial length >26.5 mm (31 patients, 62 ± 13 years old, average preoperative refraction of –14.46 ± 6.61 D, range −3.5 to −32.0 D), which underwent phacoemulsification and implantation of an intraocular lens following biometry using the IOLMaster. For lens ...

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    15. Confocal laser scanning microscopy as a new valuable tool in the diagnosis of onychomycosis – comparison of six diagnostic methods

      Confocal laser scanning microscopy as a new valuable tool in the diagnosis of onychomycosis – comparison of six diagnostic methods

      Onychomycosis is common and can mimic several different nail disorders. Accurate diagnosis is essential to choose the optimum antifungal therapy. The aim of this study was to evaluate the use of confocal laser scanning microscopy (CLSM) and optical coherence tomography (OCT) as new non-invasive diagnostic tools in onychomycosis and to compare them with the established techniques. In a prospective trial, 50 patients with suspected onychomycosis and 10 controls were examined by CLSM and OCT. Parallel KOH preparation, culture, PAS-staining and PCR were performed. PCR showed the highest sensitivity, followed by CLSM, PAS and KOH preparation. OCT offered the second best ...

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    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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