1. 721-744 of 824 « 1 2 ... 28 29 30 31 32 33 34 35 »
    1. Real-time guidance of thermal and ultrashort pulsed laser ablation in hard tissue using inline coherent imaging

      Real-time guidance of thermal and ultrashort pulsed laser ablation in hard tissue using inline coherent imaging

      Abstract Background and Objective During tissue ablation, laser light can be delivered with high precision in the transverse dimensions but final incision depth can be difficult to control. We monitor incision depth as it progresses, providing feedback to ensure that material removal occurs within a localized target volume, reducing the possibility of undesirable damage to tissues below the incision. Materials and Methods Ex vivo cortical and cancellous bone was ablated using pulsed lasers with center wavelengths of 1,064 and 1,070 nm, while being imaged in real-time using inline coherent imaging (ICI) at rates of up to 300 kHz ...

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    2. Association of coronary lipid core plaque with intrastent thrombus formation: A Near-Infrared Spectroscopy and Optical Coherence Tomography Study

      Association of coronary lipid core plaque with intrastent thrombus formation: A Near-Infrared Spectroscopy and Optical Coherence Tomography Study

      Background: Optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS) allow assessment of the anatomy (OCT) and composition (NIRS) of coronary lesions. We sought to examine the association between pre-stenting lipid core plaque (LCP), as assessed by NIRS and post-stenting thrombus formation, as assessed by OCT. Methods: We reviewed the angiograms of nine patients who underwent coronary stenting in association with NIRS and OCT imaging. A large LCP by NIRS was defined as at least three 2-mm yellow blocks on the NIRS block chemogram with >200° angular extent. Intracoronary thrombus was defined as a mass of medium reflectivity protruding into the ...

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    3. Optical coherence tomography captures rapid hemodynamic responses to acute hypoxia of the embryonic cardiovascular system of Early Embryos

      Optical coherence tomography captures rapid hemodynamic responses to acute hypoxia of the embryonic cardiovascular system of Early Embryos

      Background.The trajectory to heart defects may start in tubular and looping heart stages when detailed analysis of form and function is difficult by currently available methods. We used a novel method, Doppler optical coherence tomography (OCT), to follow changes in cardiovascular function in quail embryos during acute hypoxic stress. Chronic fetal hypoxia is a known risk factor for congenital heart diseases (CHDs). Decreased fetal heart rates during maternal obstructive sleep apnea suggest that studying fetal heart responses under acute hypoxia is warranted.Results.We captured responses to hypoxia at the critical looping heart stages. Doppler OCT revealed detailed vitelline ...

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    4. Diagnostic efficacy of backscattering intensity measurements in optical coherence tomography of cervical intraepithelial dysplasia

      Diagnostic efficacy of backscattering intensity measurements in optical coherence tomography of cervical intraepithelial dysplasia
      Background and Objectives The aim of this study was to determine the diagnostic efficacy of backscattering intensity measurements in optical coherence tomography in identifying different grades of cervical intraepithelial dysplasia. Study Design/Materials and Methods OCT images were taken from 153 unsuspicious and suspicious areas of 30 fresh conisation and hysterectomy specimens, evaluated by two blinded investigators using a six-grade classification (normal, inflammation, CIN1, CIN2, CIN3, squamous carcinoma) and later compared to the corresponding histology. Differences between judgments based on either the histology or the OCT images were investigated employing Correspondence Analysis (CA). Further, we explored the extent as to ...
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    5. Quantification of Glucose Diffusion in Human Lung Tissues by Using Fourier Domain Optical Coherence Tomography

      Quantification of Glucose Diffusion in Human Lung Tissues by Using Fourier Domain Optical Coherence Tomography

      In this study, we report permeability coefficients of 30% glucose diffusion by the optical coherence tomography signal slope (OCTSS) method in four kind of human lung tissue in vitro: normal lung tissue, benign granulomatosis lung tissue, squamous cell carcinoma, and adenocarcinoma tumor. To quantify the permeability coefficient of the agent, the monitored region was the 80 um thickness at a tissue depth of approximately 230 um from the surface. The permeability coefficients of 30% glucose from 10 independent experiments were averaged and found to be (1.35 ± 0.13)×10 −5 cm/s from the normal lung tissue, (1.78 ...

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    6. Antimicrobial Photodynamic Therapy as a Strategy to Arrest Enamel Demineralization: A Short-Term Study on Incipient Caries in a Rat Model†

      Antimicrobial Photodynamic Therapy as a Strategy to Arrest Enamel Demineralization: A Short-Term Study on Incipient Caries in a Rat Model†

      In this study we developed a rat model of incipient caries to investigate the short-term effects of antimicrobial photodynamic therapy (aPDT) on oral microbiota regulation and demineralization arrestment. Twenty nine male rats were submitted to caries induction. Early carious lesion was confirmed by optical coherence tomography (OCT) 5 days after experiment beginning in 5 animals. The remaining animals (n=24) were randomly divided into two groups: control (n=12), animals were untreated; and aPDT (n=12), animals were treated with 100μM of methylene blue for 5min and irradiated by a LED at λ=645±30nm, fluence rate of 480mW/cm2 ...

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    7. The union of Anti-CD34 antibody can improve the performance of drug-eluting stents

      The union of Anti-CD34 antibody can improve the performance of drug-eluting stents
      Objectives: The authors investigate whether the combination of anti-CD34 antibody with DES is win–win cooperation. Background: DES may reduce the risk of restenosis compared to bare-metal stents (BMS), but they were found to inhibit the healing process of intima. Methods: Fifteen BMS, 17 DES, and 16 combined anti-CD34 antibody and DES were randomly implanted in the coronary arteries of 22 minipigs. Ten minipigs were followed up to 2 weeks. The stenting coronary segments were examined by histological examination and scanning electron microscopy after in vivo coronary angiography and intracoronary optical coherence tomography (OCT) examinations. The other 12 minipigs were ...
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    8. Frontiers in Bronchoscopic Imaging

      Frontiers in Bronchoscopic Imaging
      Bronchoscopy is a minimally-invasive method for diagnosis of diseases of the airways and the lung parenchyma. Standard bronchoscopy uses the reflectance/scattering properties of white light from tissue to examine the macroscopic appearance of airways. It does not exploit the full spectrum of the optical properties of bronchial tissues. Advances in optical imaging such as optical coherence tomography (OCT), confocal endomicroscopy, autofluorescence imaging and laser Raman spectroscopy are at the forefront to allow in-vivo high resolution probing of the microscopic structure, biochemical compositions and even molecular alterations in disease states. OCT can visualize cellular and extracellular structures at and below ...
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    9. Non-destructive clinical assessment of occlusal caries lesions using near-IR imaging methods

      Non-destructive clinical assessment of occlusal caries lesions using near-IR imaging methods

      Objective Enamel is highly transparent in the near-IR (NIR) at wavelengths near 1,300 nm, and stains are not visible. The purpose of this study was to use NIR transillumination and optical coherence tomography (OCT) to estimate the severity of caries lesions on occlusal surfaces both in vivo and on extracted teeth. Methods Extracted molars with suspected occlusal lesions were examined with OCT and polarization sensitive OCT (PS-OCT), and subsequently sectioned and examined with polarized light microscopy (PLM) and transverse microradiography (TMR). Teeth in test subjects with occlusal caries lesions that were not cavitated or visible on radiographs were examined ...

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    10. Structural and functional outcomes after treatment of uveitic macular oedema: an optical coherence tomography and multifocal electroretinogram study

      Structural and functional outcomes after treatment of uveitic macular oedema: an optical coherence tomography and multifocal electroretinogram study
      Background:  The aim was to evaluate the correlation between the anatomical and functional outcomes before and after treatment of uveitic macular oedema. Methods:  Thirty-three eyes of 33 patients with uveitic macular oedema were included in the present study. Visual acuity (VA), optical coherence tomography (OCT) and multifocal electroretinogram (mfERG) were measured before and after treatment of the macular oedema. Correlation analyses between VA, OCT and mfERG parameters were performed. Results:  The VA and mfERG measurements showed statistically significant improvement after treatment of the macular oedema (p < 0.01) and OCT-measured central foveal thickness decreased significantly from 434 ± 135 µm before ...
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    11. Polypyrrole Nanoparticles: A Potential Optical Coherence Tomography Contrast Agent for Cancer Imaging

      Polypyrrole Nanoparticles: A Potential Optical Coherence Tomography Contrast Agent for Cancer Imaging

      A near-infrared (NIR) absorbing contrast agent based on polypyrrole nanoparticles is described. Quantitative optical coherence tomography studies on tissue phantoms and Mie scattering calculations indicate their potential application for early-stage cancer diagnosis.

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    12. Use of In Vivo Real-Time Optical Imaging for Esophageal Neoplasia

      Use of In Vivo Real-Time Optical Imaging for Esophageal Neoplasia
      Esophageal adenocarcinoma carries a poor prognosis, as it typically presents at a late stage. Thus, a major research priority is the development of novel diagnostic-imaging strategies that can detect neoplastic lesions earlier and more accurately than current techniques. Advances in optical imaging allow clinicians to obtain real-time histopathologic information with instant visualization of cellular architecture and the potential to identify neoplastic tissue. The various endoscopic imaging modalities for esophageal neoplasia can be grouped into 2 major categories: (1) wide-field imaging, a comparatively lower-resolution view for imaging larger surface areas, and (2) high-resolution imaging, which allows individual cells to be visualized ...
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    13. Confocal laser microscopy, optical coherence tomography and transonychial water loss for in vivo investigation of nails

      Confocal laser microscopy, optical coherence tomography and transonychial water loss for in vivo investigation of nails

      Background:  Nail disorders can be diagnostically challenging to the dermatologist. Non-invasive methods might help to avoid nail biopsies. More knowledge of the typical features of healthy nails with these techniques is needed for comparison with nail diseases.Objectives:  Objectives were to describe the typical morphology of healthy nails in optical coherence tomography (OCT) and confocal laser scanning microscopy (CLSM) and to examine the influence of exposure to water on OCT features, nail-thickness as well as on the transonychial water loss before and after a hand bath.Material and Methods:  In the first part healthy nail plates were investigated with OCT ...

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    14. Optical coherence tomography assessment of calcified plaque modification after rotational atherectomy

      Optical coherence tomography assessment of calcified plaque modification after rotational atherectomy

      Rotational atherectomy (RA) facilitates stent delivery in highly calcified coronary plaques (CCP). However, lesion ablation by RA in angulated segments may be affected by guidewire bias, leading to a non-uniform plaque modification. Intravascular optical coherence tomography (iOCT) is the highest resolution (∼10 μm axial) intravascular imaging modality available for clinical use; furthermore, near infrared light easily penetrates calcium, with significantly fewer artifacts, including no “blooming effect” as seen by intravascular ultrasound. Therefore, it may pose as a unique tool for serial calcium quantification, as related in this article with pre- and post-RA assessment, allowing accurate characterization of plaque modification, as ...

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    15. Application of optical coherence tomography in glaucoma suspect eyes

      Application of optical coherence tomography in glaucoma suspect eyes
      Purpose:  The aim of the study was to compare the optical coherence tomography (OCT) parameters of the optic nerve head (ONH) and retinal nerve fibre layer (RNFL) and to identify which measurements are best able to differentiate between normal and glaucoma suspect eyes. Methods:  The study included 27 eyes with ocular hypertension (OHT), 33 eyes with pre-perimetric glaucoma (PG), 30 perimetrically unaffected eyes of patients with glaucoma in the fellow eye (FE) and 58 eyes of age-matched normal volunteers. All subjects underwent a complete eye examination with standard automated perimetry, optic disc photography and OCT imaging. Peripapillary ‘fast RNFL thickness ...
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    16. Three-dimensional imaging of fibrous cap by frequency-domain optical coherence tomography

      Three-dimensional imaging of fibrous cap by frequency-domain optical coherence tomography

      Histopathological data correlated the presence of thin-cap fibroatheroma (TCFA) with adverse cardiovascular events. Intravascular optical coherence tomography (iOCT) is currently the only imaging modality with sufficiently high axial resolution (∼15µm) that allows direct fibrous-cap (FC) assessment in vivo. iOCT quantification of TCFA has been validated, but the assessment of a single cross-sectional image does not depict the complexity of the atherosclerotic plaque. We present two cases that illustrate the importance of three-dimensional volumetric quantification of the FC capitalizing on the properties of frequency-domain iOCT.

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    17. Barrett's esophagus: surveillance and reversal

      Barrett's esophagus: surveillance and reversal
      The following on surveillance and reversal of Barrett's esophagus (BE) includes commentaries on criteria for surveillance even when squamous epithelium stains normally with a variety of biomarkers; the long-term follow-up of surgery versus endoscopic ablation of BE; the recommended surveillance intervals in patients without dysplasia; the sampling problems related to anatomic changes following fundoplication; the value of tissue spectroscopy and optical coherence tomography; the cost-effectiveness of biopsy protocols for surveillance; the quality of life of Barrett's patients; and risk stratification and surveillance strategies.
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    18. Comparison of two artificial tear formulations for dry eye through high-resolution optical coherence tomography

      Comparison of two artificial tear formulations for dry eye through high-resolution optical coherence tomography
      Purpose:  The aim was to determine the efficacy of two artificial eye-drop formulations by analysing the lower tear film meniscus volume through a commercial high-resolution spectral-domain optical coherence tomographer. Methods:  Twenty dry eye patients (12 men, eight women, aged 57.5 ± 8.4 years) with refractive errors from -2.50 to +0.75 D (mean -1.34 ± 1.02 D) and cylinders lower than 1.00 D were examined. Tear meniscus volume was measured before, immediately after and 10, 30 and 60 minutes after instillation using the Copernicus high-resolution spectral-domain optical coherence tomographer (Optopol Tech SA, Zawiercie, Poland). Volume was ...
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    19. Noninvasive imaging of ethanol-induced developmental defects in zebrafish embryos using optical coherence tomography

      Noninvasive imaging of ethanol-induced developmental defects in zebrafish embryos using optical coherence tomography
      In this article, we report the use of optical coherence tomography for noninvasive cross-sectional real-time imaging of ethanol-induced developmental defects in zebrafish embryos larvae. For ethanol concentration of over 300 mM, developmental defects of eye (shrinkage and retinal abnormalities), malformation of the notochord and ataxia arising due to the toxic effects of ethanol were observed in OCT images from 3 days post fertilization onwards. The results suggest that OCT could be a valuable tool for noninvasive assessment of birth defects in small animal systems.
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    20. Evaluation of Neointimal Morphology of Lesions With or Without In-Stent Restenosis: An Optical Coherence Tomography Study

      Evaluation of Neointimal Morphology of Lesions With or Without In-Stent Restenosis: An Optical Coherence Tomography Study

      Background:Characterization of neointimal tissue is essential to understand the pathophysiology of in-stent restenosis (ISR) after drug-eluting stent (DES) implantation. Using optical coherence tomography (OCT), we compared the morphologic characteristics of in-stent neointimal tissue from 33 ISR lesions with those of 192 non-ISR lesions after DES implantation.Hypothesis:We hypothesized that the morphologic characteristics of in-stent neointimal tissue from ISR lesions were different from those of non-ISR lesions after DES implantation.Methods:The DES were coated with sirolimus (n=52), paclitaxel (n=57), zotarolimus (n=84), or everolimus (n=32). In-stent restenosis was defined as ≥50% diameter stenosis at the ...

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    21. Using optical coherence tomography for the longitudinal non-invasive evaluation of epidermal thickness in a murine model of chronic skin inflammation

      Using optical coherence tomography for the longitudinal non-invasive evaluation of epidermal thickness in a murine model of chronic skin inflammation
      Background Non-invasive methods are desirable for longitudinal studies examining drug efficacy and disease resolution defined as decreases in epidermal thickness in mouse models of psoriasiform skin disease. This would eliminate the need for either sacrificing animals or collecting serial skin biopsies to evaluate changes in disease progression during an individual study. The quantitation of epidermal thickness using optical coherence tomography (OCT) provides an alternative to traditional histology techniques. Methods Using the KC-Tie2 doxycycline-repressible psoriasiform skin disease mouse model, OCT imaging was completed on diseased back skin of adult KC-Tie2 (n = 3–4) and control (n = 3–4) mice, followed immediately ...
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    22. Determination of spatial correlation functions of refractive index of living tissue

      Determination of spatial correlation functions of refractive index of living tissue

      We present what to our knowledge the first method of determination of spatial correlation functions of refractive index fluctuations of living tissues by Fourier domain optical coherence tomography (FDOCT). Based on the second-order statistical description of the random characteristic of living tissue, a formula which clearly relates the spectral electrical power from the detector to the Fourier spectrum of the refractive index correlation function is given. The method is characterized by its capability of noninvasive measurements in vivo. It has the potential of allowing quantitative discrimination between different tissue types or the same tissue at different pathological states by determining ...

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    23. Optical coherence tomography in retinal detachment cases

      Optical coherence tomography in retinal detachment cases
      Purpose To report the contribution of optical coherence tomography (OCT) in the assessment of macular pathology following retinal detachment surgery. Methods OCT imaging was employed to assess macular pathology following pars plana vitrectomy or scleral buckling for the management of retinal detachment cases. Results The presence of persistent subretinal fluid, cystoid macular oedema and the formation of epiretinal membranes or macular holes were demonstrated during optical coherence tomography imaging postoperatively. In the era of spectral domain OCT greater attention has also been directed in the evaluation of any alteration, and/or disruption of the junction line between photoreceptor inner and ...
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