1. Articles from t. g. van leeuwen

    1-21 of 21
    1. Optical Coherence Tomography in Urologic Oncology: a Comprehensive Review

      Optical Coherence Tomography in Urologic Oncology: a Comprehensive Review

      Introduction Optical coherence tomography (OCT) is being investigated in urologic oncology for optical diagnosis. This comprehensive review analyzes the current state of development of OCT for bladder, upper urinary tract, kidney, prostate, testis, and penis cancer. Also, the potential role of OCT with regard to the current diagnostic pathways is critically appraised to guide future developments. Methods Embase and Pubmed were systematically searched for English and German articles on OCT in humans up to December 2017. Reviews were excluded. Case reports were excluded, unless they presented a landmark in the development of OCT. Results Out of 878 articles, 17 relevant ...

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    2. One‐to‐one registration of en‐face optical coherence tomography attenuation coefficients with histology of a prostatectomy specimen

      One‐to‐one registration of en‐face optical coherence tomography attenuation coefficients with histology of a prostatectomy specimen

      Optical coherence tomography (OCT), enables high‐resolution 3D imaging of the morphology of light scattering tissues. From the OCT signal, parameters can be extracted and related to tissue structures. One of the quantitative parameters is the attenuation coefficient; the rate at which the intensity of detected light decays in depth. To couple the quantitative parameters with the histology one‐to‐one registration is needed. The primary aim of this study is to validate a registration method of quantitative OCT parameters to histological tissue outcome through one‐to‐one registration of OCT with histology. We matched OCT images of unstained fixated ...

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    3. Optical Coherence Tomography as a Tool for in Vivo Staging and Grading of Upper Urinary Tract Urothelial Carcinoma: A Study for Diagnostic Accuracy

      Optical Coherence Tomography as a Tool for in Vivo Staging and Grading of Upper Urinary Tract Urothelial Carcinoma: A Study for Diagnostic Accuracy

      Purposes Biopsies and cytology are cornerstones in the diagnosis of upper urinary tract urothelial carcinoma (UTUC). However, a high rate of non-diagnostic biopsies, tumor upgrading and -staging after nephroureterectomy is observed. In this prospective in vivo study we aimed to evaluate the diagnostic accuracy of OCT for grading and staging of UTUC Material & Methods Twenty-six patients underwent diagnostic URS including biopsies and OCT imaging, followed by nephroureterectomy or segmental ureter resection. Sensitivity, specificity, negative predictive value and positive predictive value of UTUC grading and staging by OCT were evaluated according to the STARD initiative and second stage (2a and 2b ...

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    4. Customized Tool for the Validation of Optical Coherence Tomography in Differentiation of Prostate Cancer

      Customized Tool for the Validation of Optical Coherence Tomography in Differentiation of Prostate Cancer

      Objective: To design and demonstrate a customized tool to generate histologic sections of the prostate that directly correlate with needle-based optical coherence tomography pullback measurements. Materials and Methods: A customized tool was created to hold the prostatectomy specimens during optical coherence tomography measurements and formalin fixation. Using the tool, the prostate could be sliced into slices of 4 mm thickness through the optical coherence tomography measurement trajectory. In this way, whole-mount pathology slides were produced in exactly the same location as the optical coherence tomography measurements were performed. Full 3-dimensional optical coherence tomography pullbacks were fused with the histopathology slides ...

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    5. Volumetric laser endomicroscopy in Barrett's esophagus: a feasibility study on histological correlation

      Volumetric laser endomicroscopy in Barrett's esophagus: a feasibility study on histological correlation

      Volumetric laser endomicroscopy (VLE) is a novel balloon-based optical coherence tomography (OCT) imaging technique that may improve detection of early neoplasia in Barrett's esophagus (BE). Most OCT studies lack a direct correlation between histology and OCT images. The aim is to investigate the optimal approach for achieving one-to-one correlation of ex-vivo VLE images of endoscopic resection (ER) specimens with histology. BE patients with and without early neoplasia underwent ER after delineating areas with electrocoagulation markers (ECM). After ER, specimens underwent additional ex-vivo marking with several different markers (ink, pin, Gold Probe) followed by ex-vivo VLE scanning. ER specimens were ...

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    6. Detecting signs of retinal leakage in exudative AMD using Cirrus OCT versus SL SCAN-1, a novel integrated FD-OCT into a common slit lamp

      Detecting signs of retinal leakage in exudative AMD using Cirrus OCT versus SL SCAN-1, a novel integrated FD-OCT into a common slit lamp

      Purpose The purpose is to evaluate the interdevice and interobserver agreements between the SL SCAN-1 (a FD-OCT integrated into a common slit lamp) and a standard stand-alone FD-OCT device (the Cirrus ) with regard to the presence or absence of signs of leakage in the retina in patients with exudative AMD and treated with anti- VEGF . Methods Fifty-six patients, known to have exudative AMD and under treatment with anti- VEGF agents, were included. During a regular follow-up, OCT scans were made with the Cirrus (macular-cube pattern) and the SL SCAN-1 (radial-scan pattern). All scans were graded by two medical retina specialists ...

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    7. Functional optical coherence tomography of pigmented lesions

      Functional optical coherence tomography of pigmented lesions

      Background Cutaneous melanomas are diagnosed worldwide in 231 130 patients per year. The sensitivity and specificity of melanoma diagnosis expresses the need for an additional diagnostic method. Optical coherence tomography (OCT) has shown that it allows morphological (qualitative) description of image features and quantitative analysis of pathology related light scattering by means of the attenuation coefficient (μ oct ). Objective We hypothesize that OCT images of nevi will differ qualitatively and quantitatively from melanomas. Methods Forty lesions from 33 consecutive patients were imaged with OCT. After data acquisition, excision was performed. Epidermal layer thickness was measured and values of μ oct were extracted ...

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    8. Video Interview on Optical coherence tomography as a tool for in vivo staging and grading of upper urinary tract urothelial cell carcinoma: Comparison with biopsies and histopathology of the resected specimen

      Video Interview on Optical coherence tomography as a tool for in vivo staging and grading of upper urinary tract urothelial cell carcinoma: Comparison with biopsies and histopathology of the resected specimen

      Introduction and Objectives: Optical Coherence Tomography (OCT) has potential to provide real-time information on UUT-UC grade and stage. In this study we compare a) biopsy and b) OCT with gold standard histopathology of the resected specimen (HRS) for grading and staging of low- and high-grade UUT-UC. Methods: 16 patients with UUT-UC underwent diagnostic URS, including OCT and biopsy of places with visible tumour. The 2.7 Fr OCT probe was delivered through the ureteroscopes work channel. Subsequently biopsy was performed. At a later stage, patients underwent nephroureterectomy. For staging by OCT, in-house developed protocols were used and visible lesions were ...

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    9. Functional optical coherence tomography of pigmented lesions

      Functional optical coherence tomography of pigmented lesions

      Background Cutaneous melanomas are diagnosed worldwide in 231 130 patients per year. The sensitivity and specificity of melanoma diagnosis expresses the need for an additional diagnostic method. Optical coherence tomography (OCT) has shown that it allows morphological (qualitative) description of image features and quantitative analysis of pathology related light scattering by means of the attenuation coefficient (μ oct ). Objective We hypothesize that OCT images of nevi will differ qualitatively and quantitatively from melanomas. Methods Forty lesions from 33 consecutive patients were imaged with OCT. After data acquisition, excision was performed. Epidermal layer thickness was measured and values of μ oct were extracted ...

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    10. Dependent and multiple scattering in transmission and backscattering optical coherence tomography

      Dependent and multiple scattering in transmission and backscattering optical coherence tomography

      We use transmission and backscattering optical coherence tomography (OCT) to distinguish and quantify dependent and multiple scattering effects in turbid media. With transmission OCT the dependent scattering coefficients for a range of monodisperse silica particle suspensions are determined. An excellent agreement is observed between the measured dependent scattering coefficients and calculations based on Mie calculations, the Percus-Yevick radial distribution function, and coherent light scattering theory. Backscattering OCT measurements are fitted using the extended Huygens-Fresnel (EHF) model with the dependent scattering coefficients obtained from the transmission OCT measurements as input parameters. Good agreement between the EHF model and the backscattering OCT ...

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    11. Volumetric In-Vivo Visualization of Upper Urinary Tract Tumors Using Optical Coherence Tomography: A Pilot Study

      Volumetric In-Vivo Visualization of Upper Urinary Tract Tumors Using Optical Coherence Tomography: A Pilot Study

      Purpose Knowledge on tumor stage and grade is paramount for treatment decision in Upper Urinary Tract Urothelial Carcinoma (UUT-UC), but cannot be accurately assessed by current techniques. Optical Coherence Tomography (OCT) is a technique, which can hypothetically provide the urologist with real-time intra-operative information on tumor grade and stage. In this pilot study the first results of OCT in grading and staging of UUT-UC are presented. Material & Methods Eight consecutive patients underwent URS for UUT-UC suspicion or follow-up. OCT datasets were intra-operatively obtained from the ureter and pyelum. All patients eventually underwent nephroureterectomy. OCT staging was performed by visual inspection ...

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    12. Optical biopsy of epithelial cancers by optical coherence tomography (OCT)

      Optical biopsy of epithelial cancers by optical coherence tomography (OCT)

      Optical coherence tomography (OCT) is an optical technique that measures the backscattering of near-infrared light by tissue. OCT yields in 2D and 3D images at micrometer-scale resolution, thus providing optical biopsies, approaching the resolution of histopathological imaging. The technique has shown to allow in vivo differentiation between benign and malignant epithelial tissue, through qualitative assessment of OCT images, as well as by quantitative evaluation, e.g., functional OCT. This study aims to summarize the principles of OCT and to discuss the current literature on the diagnostic value of OCT in the diagnosis of epithelial (pre)malignant lesions. The authors did ...

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    13. Feature Of The Week 1/27/13: An Exciting and Promising Area for OCT System Research and Commercial Opportunities

      Feature Of The Week 1/27/13: An Exciting and Promising Area for OCT System Research and Commercial Opportunities

      One of the most promising areas for OCT system research is the pursuit of photonic integrated circuits (PICs) and optoelectronic integrated circuits (OEICs) for OCT systems. Such approaches offer to dramatically reduce the size, weight, power, and costs of future OCT systems. Such reductions could enable increase adoption of OCT in existing markets and open up a wide range of new applications and markets for OCT. While there remain several difficult challenges ahead there has already been massive R&D investments (~$100M) and major advances in this area in the fiber optic telecommunication industry and those advances are poised ...

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    14. Integrated-optics-based swept-source optical coherence tomography

      Integrated-optics-based swept-source optical coherence tomography

      We designed, fabricated, and characterized an integrated-optics-based swept-source optical coherence tomography (SS-OCT) system in TriPleX technology. An external 1300 nm swept source is coupled to the chip, which contains waveguide structures for interferometric depth ranging and balanced detection. The complete OCT chip has a footprint of 0.4     cm × 1.8     cm . Light from the chip is focused onto the s.ample using an aspheric lens; the lateral resolution is 21 ± 1     μ m . OCT measurements, performed with a moveable mirror, demonstrate a sensitivity of − 80     dB and imaging up to the maximum depth of 5.09 mm. Corrected for dispersion ...

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    15. Multiple scattering effects in Doppler optical coherence tomography of flowing blood

      Multiple scattering effects in Doppler optical coherence tomography of flowing blood

      We investigate the effect of multiple scattering on the optical coherence tomography (OCT) signal and the Doppler OCT signal of flowing blood. Doppler OCT measurements at 1300 nm are performed on flowing diluted porcine blood with hematocrit ranging between 0% and 15%. Measured blood hematocrit and mean red blood cell volume are used to calculate, using the discrete dipole approximation model, the (single) scattering coefficient and scattering anisotropy of blood. Monte Carlo simulations, based on the calculated scattering coefficients and scattering anisotropies, are compared to Doppler OCT measurements for hematocrit smaller than 10%. Good quantitative agreement between Doppler OCT measurements ...

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    16. Determination of the scattering anisotropy with optical coherence tomography

      Determination of the scattering anisotropy with optical coherence tomography
      In this work we demonstrate measurements with optical coherence tomography (OCT) of the scattering phase function in the backward direction and the scattering anisotropy parameter g. Measurements of the OCT attenuation coefficient and the backscattering amplitude are performed on calibrated polystyrene microspheres with a time-domain OCT system. From these measurements the phase function in the backward direction is determined. The measurements are described by the single scattering model and match Mie calculations very well. Measurements on Intralipid demonstrate the ability to determine the g of polydisperse samples and, for Intralipid, g = 0.35 ± 0.03 is measured, which is well ...
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    17. Scanning beyond the limits of standard OCT with a Fourier domain optical coherence tomography integrated into a slit lamp: the SL SCAN-1

      Scanning beyond the limits of standard OCT with a Fourier domain optical coherence tomography integrated into a slit lamp: the SL SCAN-1

      PurposeWith a new Fourier domain optical coherence tomography (FD OCT) device, SL SCAN-1 (Topcon Europe Medical BV, Capelle a/d IJssel, The Netherlands), integrated into a slit-lamp OCT, scans can be obtained through a handheld lens. The necessary adjustment of the reference arm is possible by fast Z-alignment. This study was performed to prove the capability of SL SCAN-1 to scan through a three-mirror contact lens, scanning the peripheral retina and anterior chamber angle.MethodsDifferent representative pathologies of the peripheral retina and anterior chamber were simultaneously observed and scanned with the SL SCAN-1. The scans of peripheral retinal lesions were ...

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    18. Path-Length-Resolved Diffusive Particle Dynamics in Spectral-Domain Optical Coherence Tomography

      Path-Length-Resolved Diffusive Particle Dynamics in Spectral-Domain Optical Coherence Tomography
      We describe a new method to measure the decorrelation rate of the optical coherence tomography (OCT) magnitude simultaneously in space and time.We measure the decorrelation rate of the OCT magnitude in a Fourier-domain OCT system for a large range of translational diffusion coefficients by varying the sphere diameter. The described method uses the sensitivity advantage of Fourier-domain OCT over time-domain OCT to increase the particle diffusion imaging speed by a factor of 200. By coherent gating, we reduce the contribution of multiple scattering to the detected signal, allowing a quantitative study of diffusive particle dynamics in high concentration samples ...
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    19. Quantitative comparison of the OCT imaging depth at 1300 nm and 1600 nm

      Quantitative comparison of the OCT imaging depth at 1300 nm and 1600 nm
      One of the present challenges in optical coherence tomography (OCT) is the visualization of deeper structural morphology in biological tissues. Owing to a reduced scattering, a larger imaging depth can be achieved by using longer wavelengths. In this work, we analyze the OCT imaging depth at wavelengths around 1300 nm and 1600 nm by comparing the scattering coefficient and OCT imaging depth for a range of Intralipid concentrations at constant water content. We observe an enhanced OCT imaging depth for 1600 nm compared to 1300 nm for Intralipid concentrations larger than 4 vol.%. For higher Intralipid concentrations, the imaging depth ...
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    20. Multiple and dependent scattering effects in Doppler optical coherence tomography

      Multiple and dependent scattering effects in Doppler optical coherence tomography
      Doppler optical coherence tomography (OCT) is a technique to image tissue morphology and to measure flow in turbid media. In its most basic form, it is based on single (Mie) scattering. However, for highly scattering and dense media multiple and concentration dependent scattering can occur. For Intralipid solutions with varying scattering strength, the effect of multiple and dependent scattering on the OCT signal attenuation and Doppler flow is investigated. We observe a non-linear increase in the OCT signal attenuation rate and an increasingly more distorted Doppler OCT flow profile with increasing Intralipid concentration. The Doppler OCT attenuation and flow measurements ...
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    21. Fourier Domain Optical Coherence Tomography integrated into a slit lamp; a novel technique combining anterior and posterior segment OCT

      Purpose Fourier Domain Optical Coherence Tomography (FD-OCT) provides high resolution cross-sectional images of the retina and the anterior segment. It has become an important tool in ophthalmology in the examination, diagnosis, and treatment of important and common diseases. Present OCT imaging systems are stand-alone devices. The aim of this paper is to show the quality of images made with a prototype of a Fourier Domain (FD-) OCT imaging system (SLSCAN-1) integrated into a slit lamp.Methods Different representative pathologies of the posterior and anterior segment were observed with the slit lamp and simultaneously scanned with a prototype of the slit ...

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    1-21 of 21
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    1. (21 articles) Ton G. van Leeuwen
    2. (18 articles) Academic Medical Center at the University of Amsterdam
    3. (13 articles) Dirk J. Faber
    4. (10 articles) Daniël M. de Bruin
    5. (8 articles) Jeroen Kalkman
    6. (6 articles) University of Twente
    7. (5 articles) Jean J. M. C. H. de la Rosette
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    Multiple and dependent scattering effects in Doppler optical coherence tomography Quantitative comparison of the OCT imaging depth at 1300 nm and 1600 nm Path-Length-Resolved Diffusive Particle Dynamics in Spectral-Domain Optical Coherence Tomography Scanning beyond the limits of standard OCT with a Fourier domain optical coherence tomography integrated into a slit lamp: the SL SCAN-1 Determination of the scattering anisotropy with optical coherence tomography Multiple scattering effects in Doppler optical coherence tomography of flowing blood Integrated-optics-based swept-source optical coherence tomography Feature Of The Week 1/27/13: An Exciting and Promising Area for OCT System Research and Commercial Opportunities Volumetric In-Vivo Visualization of Upper Urinary Tract Tumors Using Optical Coherence Tomography: A Pilot Study Duke University Engineering Professor Sina Farsiu Elected Fellow of the IEEE PhotoniCare Takes First Place at the 2019 HealthTECH Startup Competition Close Assessment and Testing for Chronic Graft Versus Host Disease, CATCH Study