1. 1-24 of 158 1 2 3 4 5 6 7 »
    1. Application of an OCT data-based mathematical model of the foveal pit in Parkinson disease

      Application of an OCT data-based mathematical model of the foveal pit in Parkinson disease

      Spectral-domain Optical coherence tomography (OCT) has shown remarkable utility in the study of retinal disease and has helped to characterize the fovea in Parkinson disease (PD) patients. We developed a detailed mathematical model based on raw OCT data to allow differentiation of foveae of PD patients from healthy controls. Of the various models we tested, a difference of a Gaussian and a polynomial was found to have "the best fit". Decision was based on mathematical evaluation of the fit of the model to the data of 45 control eyes versus 50 PD eyes. We compared the model parameters in the ...

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    2. Impact of strut-vessel distance and underlying plaque type on the resolution of acute strut malapposition: serial optimal coherence tomography analysis after everolimus-eluting stent implantation

      Impact of strut-vessel distance and underlying plaque type on the resolution of acute strut malapposition: serial optimal coherence tomography analysis after everolimus-eluting stent implantation

      The consequences of acute strut malapposition in everolimus-eluting stents (EES) are unknown. This study investigated the impact of strut–vessel (S–V) distance and plaque type underneath acute strut malapposition on the mid-term vessel response in EES. Twenty-nine patients (35 EES) underwent optical coherence tomography (OCT) immediately after percutaneous coronary intervention and at 8-month follow-up. S–V distance and plaque type (lipid, calcified, or fibrous) underneath acute strut malapposition were evaluated. Follow-up OCT classified acute strut malapposition as persistent or resolved. The S–V cutoff value for predicting resolved strut malapposition and the incidence of intra-stent thrombi were determined. Among ...

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    3. Intra-operative OCT devices for ophthalmic use: an overview

      Intra-operative OCT devices for ophthalmic use: an overview

      It is feasible to bring the currently most used examination method in ophthalmology, optical coherence tomography (OCT), into ophthalmic surgery to enhance information and control for the surgeon and increase outcome for the patient. In this overview, the currently commercially available OCT devices intending intra-operative OCT imaging are described. Further experience with these systems might not only aid in solving current problems but also open our minds to detect processes so far unknown and help answer questions so far unaddressed.

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    4. Phase correction using programmable phase modulator (PPM) in optical coherence tomography

      Phase correction using programmable phase modulator (PPM) in optical coherence tomography

      Purpose Adaptive optics is used in optical coherence tomography (OCT) in order to improve lateral resolution based on aberration correction. Methods Experiments were performed to compensate higher order aberrations based on wavefront sensing and correction scheme using adaptive optics. The device utilized for compensation is parallel-aligned nematic liquid crystal spatial light modulator (PAL-SLM), PPM X7550 series. Wavefront of light at the sample path was measured by using OCT for aberration correction. Since the phase information can be obtained from interferogram therefore no additional optics is used. The performance of this device is evaluated for the correction of linear tilt aberration ...

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    5. Serial optical coherence tomography assessments at 2- and 4-month follow-up after paclitaxel-eluting stenting of the superficial femoral artery

      Serial optical coherence tomography assessments at 2- and 4-month follow-up after paclitaxel-eluting stenting of the superficial femoral artery

      A 71-year-old man underwent endovascular therapy (EVT) with a paclitaxel-eluting stent in superficial femoral artery (SFA). Optical coherence tomography (OCT) of SFA at 2 months after EVT revealed that several struts were not covered with neointima. Moreover, some mural thrombi were detected within the stent. Although OCT revealed that the frequency of stent strut coverage was improved at the 4-month follow-up, uncovered stent strut still remained and some mural thrombi were observed within the stent even at 4 months after EVT. This is the first report to demonstrate the vascular response after paclitaxel-eluting stent placement for the lesion using serial ...

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    6. Emerging endoscopic imaging technologies for bladder cancer detection

      Emerging endoscopic imaging technologies for bladder cancer detection

      Modern urologic endoscopy is the result of continuous innovations since the early nineteenth century. White-light cystoscopy is the primary strategy for identification, resection, and local staging of bladder cancer. While highly effective, white light cystoscopy has several well-recognized shortcomings. Recent advances in optical imaging technologies and device miniaturization hold the potential to improve bladder cancer diagnosis and resection. Photodynamic diagnosis and narrow band imaging are the first to enter the clinical arena. Confocal laser endomicroscopy, optical coherence tomography, Raman spectroscopy, UV autofluorescence, and others have shown promising clinical and pre-clinical feasibility. We review their mechanisms of action, highlight their respective ...

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    7. Spectral Domain Optical Coherence Tomography Findings in CNGB3-Associated Achromatopsia and Therapeutic Implications

      Spectral Domain Optical Coherence Tomography Findings in CNGB3-Associated Achromatopsia and Therapeutic Implications

      We describe the spectral domain OCT findings in two siblings with CNGB3-associated achromatopsia. A 33-year-old female and her 31-year-old sibling were evaluated for mild nystagmus and decreased visual acuity which had been present since childhood. They were each evaluated with full field Ganzfeld electroretinography which demonstrated flat photopic responses and preserved rod function. Genetic testing performed at Carver lab at the University of Iowa confirmed a diagnosis of achromatopsia with identical mutations in the CNGB3 gene. Spectral domain optical coherence tomography was performed which revealed foveal changes in both siblings, with slight phenotypic variations in these genotypically identical siblings. OCT ...

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    8. Automated detection and quantification of clusters of malapposed and uncovered intracoronary stent struts assessed with optical coherence tomography

      Automated detection and quantification of clusters of malapposed and uncovered intracoronary stent struts assessed with optical coherence tomography

      To date, accurate quantification and localization of malapposed and uncovered struts needs manual and time consuming analysis of large datasets. To develop an algorithm for automated detection and quantification of clusters of malapposed and uncovered struts in optical coherence tomography (OCT) pullbacks, including comprehensive information about their three-dimensional spatial distribution. 64 lesions in 64 patients treated with drug-eluting stent underwent assessment with OCT immediately after implantation and at 9-month follow-up (55 patients). An automated algorithm was used to detect and quantify stent strut malapposition at baseline and coverage at follow-up on an individual strut level. We subsequently applied an algorithm ...

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    9. Intra-Coronary Imaging Modalities

      Intra-Coronary Imaging Modalities

      The use of intracoronary imaging modalities has seen a significant increase over the past decade, as both imaging quality and delivery systems have improved. Generally accepted best practice indications for using intracoronary imaging include assessment of lesion characteristics prior to stent placement, optimization of stent placement with respect to appropriate sizing, adequate apposition, and expansion and exclusion of edge dissection. Intracoronary imaging plays a particular role in the setting of contemporary left main and bifurcation stenting. Stent interrogation using intracoronary imaging to exclude mechanical causes in the management of in-stent thrombosis has also become conventional. Current clinical guideline recommendations, however ...

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    10. Growth Kinetics of Concave Nanocubes Studied by Optical Coherence Tomography

      Growth Kinetics of Concave Nanocubes Studied by Optical Coherence Tomography

      This work presents the analysis of the growth kinetics of two syntheses of concave gold nanocubes with a mean size of 72 and 108 nm followed by the optical coherence tomography (OCT) technique by acquiring B-scan images each 5 s. In addition, ultra violet-visible (UV-Vis) spectra and mean size from dynamic light scattering (DLS) were acquired during nanoparticle growth to generate kinetic plots in order to corroborate the OCT results. Kinetic plots from OCT images were obtained by plotting contrast enhancement of B-scan images as function of time. Fitting parameters values given by using the classical Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation show ...

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    11. Comparative study of macular ganglion cell complex thickness measured by spectral-domain optical coherence tomography in healthy eyes, eyes with preperimetric glaucoma, and eyes with early glaucoma

      Comparative study of macular ganglion cell complex thickness measured by spectral-domain optical coherence tomography in healthy eyes, eyes with preperimetric glaucoma, and eyes with early glaucoma

      Purpose To evaluate the diagnostic accuracy of Topcon 3D spectral-domain optical coherence tomography (SD-OCT) for measuring the macular inner retinal layers and the circumpapillary retinal nerve fiber layer (cpRNFL) in order to detect preperimetric glaucoma. Methods Two hundred four eyes, including 64 healthy eyes, 68 eyes with preperimetric glaucoma, and 72 eyes with early glaucoma were analyzed. Patients had a comprehensive ocular examination including visual field testing and SD-OCT imaging (3D OCT-2000; Topcon Corporation, Tokyo, Japan) in the macular and peripapillary regions. OCT macular scans were segmented into the macular nerve fiber layer (mNFL), ganglion cell layer with the inner ...

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    12. Worsening late-acquired incomplete stent apposition after sirolimus-eluting stent implantation for a chronic total occlusion lesion

      Worsening late-acquired incomplete stent apposition after sirolimus-eluting stent implantation for a chronic total occlusion lesion

      A 70-year-old man underwent percutaneous coronary intervention (PCI) using sirolimus-eluting stent (SES) at the just proximal site of left anterior descending coronary artery. Six months after SES implantation, he suffered from late stent thrombosis. Intravascular ultrasound (IVUS) images demonstrated positive remodeling of the vessel, indicating late-acquired incomplete stent apposition (ISA). An angioplasty with a bigger balloon was performed to obtain sufficient stent struts apposition. Twenty-six months after the second PCI, he developed ST-elevation myocardial infarction and his CAG showed re-occlusion of the SES. Optical coherence tomography showed ISA and IVUS revealed further enlargement of the coronary artery around the SES.

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    13. Optical coherence tomography provides images similar to histology and allows the performance of extensive measurements of drug-eluting metal stents in animal ureter

      Optical coherence tomography provides images similar to histology and allows the performance of extensive measurements of drug-eluting metal stents in animal ureter

      Optical coherence tomography (OCT) images and histology images of metal stents (MSs) inserted in animal ureters were compared, and the reliability of an OCT-based automated method for the performance of quantitative evaluation of ureteral MSs was evaluated. A zotarolimus-eluting metal stent (ZES) and a bare metal stent (BMS) were inserted in each ureter of ten pigs and six rabbits. OCT was performed in unobstructed stented ureters. Histopathologic examination of the stented ureters embedded in glycol-methacrylate took place. Quadrants of OCT images were compared to their respective histologic images by employing two independent observers who delineated different layers in the quadrants ...

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    14. Correlation of morphological pattern of optical coherence tomography in diabetic macular edema with systemic risk factors in middle aged males

      Correlation of morphological pattern of optical coherence tomography in diabetic macular edema with systemic risk factors in middle aged males

      To study correlation of different optical coherence tomography (OCT) patterns of diabetic macular edema (DME) with systemic risk factors. Institutional cross-sectional double-masked non-interventional study with 330 eyes of middle-aged male type 2 diabetes patients with DME. Various systemic parameters were measured. Diffuse retinal thickening (DRT), cystoid and serous patterns of DME were identified on OCT. Comparison between DRT versus non-DRT and serous versus non-serous eyes was done in respect to systemic parameters. Correlation of serous and DRT pattern was tested with systemic parameters above and below specified values. Mean age was 54.4 ± 7.1 years. Mean duration of diabetes ...

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    15. The influence of axial length on confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography size measurements: a pilot study

      The influence of axial length on confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography size measurements: a pilot study

      Purpose To investigate the influence of axial length on SD-OCT and cSLO size measurements from the Heidelberg Spectralis. Methods In this pilot study, eight emmetropic pseudophakic eyes with subretinal visual implant were selected. The axial length was measured in three short (<22.5 mm), three medium (22.51–25.50 mm) and two long (>25.52 mm) eyes. The known size of subretinal implant sensor field (2800 × 2800 μm) was measured on 15 images per eye with cSLO and SD-OCT. Results The mean axial length was 20.8 ± 0.8 mm in short eyes, 23.3 ± 0.4 mm in ...

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    16. Evaluation of graft-host interface after penetrating keratoplasty using anterior segment optical coherence tomography

      Evaluation of graft-host interface after penetrating keratoplasty using anterior segment optical coherence tomography

      PURPOSE: To evaluate the characteristics of the graft-host interface after penetrating keratoplasty (PKP) using anterior segment optical coherence tomography (AS-OCT). METHODS: Forty-nine eyes of 49 patients with three different underlying diseases (corneal scar, 22 eyes; bullous keratopathy, 14 eyes; keratoconus, 13 eyes) who underwent PKP were retrospectively reviewed. AS-OCT was performed in all patients and wound profiles of the graft-host junctions were classified into well-apposed junction, gap, step, and protrusion. The correlations between clinical characteristics and wound profiles from the AS-OCT were analyzed. RESULTS: A total of 392 graft-host junctions from 49 eyes were analyzed. Among them, 155 sections (39 ...

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    17. Hydrogel-Forming Microneedle Arrays Can Be Effectively Inserted in Skin by Self-Application: A Pilot Study Centred on Pharmacist Intervention and a Patient Information Leaflet

      Hydrogel-Forming Microneedle Arrays Can Be Effectively Inserted in Skin by Self-Application: A Pilot Study Centred on Pharmacist Intervention and a Patient Information Leaflet

      Purpose To investigate, for the first time, the influence of pharmacist intervention and the use of a patient information leaflet on self-application of hydrogel-forming microneedle arrays by human volunteers without the aid of an applicator device. Methods A patient information leaflet was drafted and pharmacist counselling strategy devised. Twenty human volunteers applied 11 × 11 arrays of 400 μm hydrogel-forming microneedle arrays to their own skin following the instructions provided. Skin barrier function disruption was assessed using transepidermal water loss measurements and optical coherence tomography and results compared to those obtained when more experienced researchers applied the microneedles to the volunteers ...

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    18. Single longitudinal mode Ytterbium doped fiber lasers with large proposed tuning range

      Single longitudinal mode Ytterbium doped fiber lasers with large proposed tuning range

      A 1,064 nm band Ytterbium doped fiber laser (YDFL) is proposed and investigated. Using 70 cm gain fiber and recycling pumping scheme, a high slope efficiency of 50 % and low threshold power of 53 mW are obtained. The power variation is less than 0.1 dB in 13 nm tuning span. Using the Vernier effect, near single frequency lasing is realized for the whole tuning range in 2 dBm output power. Have advantages of simpler structure, larger pump slope efficiency and possible shorter cavity, the YDFL may find potential applications in various ways.

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    19. Characterization of transparent dentin in attrited teeth using optical coherence tomography

      Characterization of transparent dentin in attrited teeth using optical coherence tomography

      Attrition and wear of tooth surface occur with aging and result in loss of enamel, with exposure and histological changes in dentin. Dealing with attrited teeth and restoration of the lost tissue are clinically challenging. The main objective of this study is to characterize the exposed transparent dentin in the occlusal surface of attrited teeth by optical coherence tomography (OCT). Naturally attrited, extracted human teeth with occlusal-transparent dentin were investigated in comparison to sound and carious teeth. The teeth were subjected to OCT imaging and then cross-sectioned and polished. OCT B-scans were compared to light microscopy images of the same ...

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    20. Macular optical coherence tomography findings and GPR143 mutations in patients with ocular albinism

      Macular optical coherence tomography findings and GPR143 mutations in patients with ocular albinism

      The aim of this study was to describe macular findings using spectral-domain optical coherence tomography (SD-OCT) in patients with ocular albinism (OA) and their carrier mothers, and to identify the frequency of GPR143 gene mutations in these patients. The study included five patients with a clinical diagnosis of OA. SD-OCT of the macular area was performed in both patients and their mothers. The anatomical characteristics of the macula and retinal pigment epithelium (RPE), patterns of autofluorescence and infrared imaging were analyzed. Polymerase chain reaction amplification of the complete coding sequence of GPR 143 was performed and subsequently analyzed by direct ...

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    21. Optical coherence tomography: a quantitative tool to screen for papilledema in craniosynostosis

      Optical coherence tomography: a quantitative tool to screen for papilledema in craniosynostosis

      Purpose Our aim was to evaluate if optical coherence tomography (OCT) can be used as an alternative for fundoscopy to screen for increased intracranial pressure (ICP) in children with craniosynostosis Methods We performed a prospective cohort study at the Dutch Craniofacial Centre. We included 38 patients with nonsyndromic scaphocephaly and Crouzon’s syndrome aged 3–8 years old, in whom we scored complaints suggestive of increased ICP and performed fundoscopy and OCT. Main outcome measures total retinal thickness (TRT) which was measured on 58 OCT scans. Results Forty-three percent of fundoscopies revealed pathologic changes of the papil in at least ...

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    22. Comparison of slit lamp-adapted optical coherence tomography features of fellow eyes of acute primary angle closure and eyes with open angle glaucoma

      Comparison of slit lamp-adapted optical coherence tomography features of fellow eyes of acute primary angle closure and eyes with open angle glaucoma

      Purpose The aim of this study was to assess the possibility of discriminating a narrow and occludable chamber angle by means of digital gonioscopy. Methods In a prospective controlled clinical study 40 eyes of 40 patients were enrolled. 20 patients that had suffered acute angle closure glaucoma (ACG) on the fellow eye were compared to 20 patients with open angle glaucoma (OAG). Anterior segment imaging with SL-OCT (Heidelberg Engineering, Heidelberg, Germany) enabled the delineation, by means of automatic signal analysis, of several important parameters of the anterior chamber angle region, which were compared to those revealed from direct contact glass ...

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    23. Vascular Imaging in Diabetes

      Vascular Imaging in Diabetes

      Diabetes is a global epidemic affecting individuals of all socioeconomic backgrounds. Despite intensive efforts, morbidity and mortality secondary to the micro- and macrovascular complications remain unacceptably high. As a result, the use of imaging modalities to determine the underlying pathophysiology, early onset of complications, and disease progression has become an integral component of the management of such individuals. Echocardiography, stress echocardiography, and nuclear imaging have been the mainstay of noninvasive cardiovascular imaging tools to detect myocardial ischemia, but newer modalities such as cardiac MRI, cardiac CT, and PET imaging provide incremental information not available with standard imaging. While vascular imaging ...

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    1-24 of 158 1 2 3 4 5 6 7 »
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