1. Articles from Dirk J. Faber

    1-24 of 35 1 2 »
    1. Needle-based optical coherence tomography for the detection of prostate cancer: a visual and quantitative analysis in 20 patients

      Needle-based optical coherence tomography for the detection of prostate cancer: a visual and quantitative analysis in 20 patients

      iagnostic accuracy of needle-based optical coherence tomography (OCT) for prostate cancer detection by visual and quantitative analysis is defined. 106 three-dimensional (3-D)-OCT data sets were acquired in 20 prostates after radical prostatectomy and precisely matched with pathology. OCT images were grouped per histological category. Two reviewers performed blind assessments of the OCT images. Sensitivity and specificity for malignancy detection were calculated. Quantitative analyses by automated optical attenuation coefficient calculation were performed. OCT can reliably differentiate between fat, cystic, and regular atrophy and benign glands. The overall sensitivity and specificity for malignancy detection was 79% and 88% for reviewer 1 ...

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    2. Ex-vivo study in nephroureterectomy specimens defining the role of 3-D upper urinary tract visualization using optical coherence tomography and endoluminal ultrasound

      Ex-vivo study in nephroureterectomy specimens defining the role of 3-D upper urinary tract visualization using optical coherence tomography and endoluminal ultrasound

      Minimal invasive endoscopic treatment for upper urinary tract urothelial carcinoma (UUT-UC) is advocated in patients with low-risk disease and limited tumor volume. Diagnostic ureterorenoscopy combined with biopsy is the diagnostic standard. This study aims to evaluate two alternative diagnostic techniques for UUT-UC: optical coherence tomography (OCT) and endoluminal ultrasound (ELUS). Following nephroureterectomy, OCT, ELUS, and computed tomography (CT) were performed of the complete nephroureterectomy specimen. Visualization software (AMIRA®) was used for reconstruction and coregistration of CT, OCT, and ELUS. Finally, CT was used to obtain exact probe localization. Coregistered OCT and ELUS datasets were compared with histology. Coregistration with three-dimensional ...

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    3. OCT Amplitude and Speckle Statistics of Discrete Random Media

      OCT Amplitude and Speckle Statistics of Discrete Random Media

      Speckle, amplitude fluctuations in optical coherence tomography (OCT) images, contains information on sub-resolution structural properties of the imaged sample. Speckle statistics could therefore be utilized in the characterization of biological tissues. However, a rigorous theoretical framework relating OCT speckle statistics to structural tissue properties has yet to be developed. As a first step, we present a theoretical description of OCT speckle, relating the OCT amplitude variance to size and organization for samples of discrete random media (DRM). Starting the calculations from the size and organization of the scattering particles, we analytically find expressions for the OCT amplitude mean, amplitude variance ...

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    4. Visibility of Fiducial Markers used for Image-Guided Radiation Therapy on Optical Coherence Tomography for Registration with CT: an Esophageal Phantom Study

      Visibility of Fiducial Markers used for Image-Guided Radiation Therapy on Optical Coherence Tomography for Registration with CT: an Esophageal Phantom Study

      Purpose Optical coherence tomography (OCT) is of interest to visualize microscopic esophageal tumor extensions to improve tumor delineation for radiation therapy (RT) planning. Fiducial marker placement is a common method to ensure target localization during planning and treatment. Visualization of these fiducial markers on OCT permits integrating OCT and computed tomography (CT) images used for RT planning via image registration. We studied the visibility of 13 (8 types) commercially available solid and liquid fiducial markers in OCT images at different depths using dedicated esophageal phantoms and evaluated marker placement depth in clinical practice. Materials and Methods We designed and fabricated ...

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    5. Applicability of quantitative optical imaging techniques for intraoperative perfusion diagnostics: a comparison of laser speckle contrast imaging, sidestream dark-field microscopy, and optical coherence tomography

      Applicability of quantitative optical imaging techniques for intraoperative perfusion diagnostics: a comparison of laser speckle contrast imaging, sidestream dark-field microscopy, and optical coherence tomography

      . Patient morbidity and mortality due to hemodynamic complications are a major problem in surgery. Optical techniques can image blood flow in real-time and high-resolution, thereby enabling perfusion monitoring intraoperatively. We tested the feasibility and validity of laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), and sidestream dark-field microscopy (SDF) for perfusion diagnostics in a phantom model using whole blood. Microvessels with diameters of 50, 100, and 400 μm were constructed in a scattering phantom. Perfusion was simulated by pumping heparinized human whole blood at five velocities (0 to 20 mm∕s). Vessel diameter and blood flow velocity were assessed ...

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    6. Validation of quantitative attenuation and backscattering coefficient measurements by optical coherence tomography in the concentration-dependent and multiple scattering regime

      Validation of quantitative attenuation and backscattering coefficient measurements by optical coherence tomography in the concentration-dependent and multiple scattering regime

      Optical coherence tomography (OCT) has the potential to quantitatively measure optical properties of tissue such as the attenuation coefficient and backscattering coefficient. However, to obtain reliable values for strong scattering tissues, accurate consideration of the effects of multiple scattering and the nonlinear relation between the scattering coefficient and scatterer concentration (concentration-dependent scattering) is required. We present a comprehensive model for the OCT signal in which we quantitatively account for both effects, as well as our system parameters (confocal point spread function and sensitivity roll-off). We verify our model with experimental data from controlled phantoms of monodisperse silica beads (scattering coefficients ...

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    7. Percutaneous Needle Based Optical Coherence Tomography for the Differentiation of Renal Masses: a Pilot Cohort

      Percutaneous Needle Based Optical Coherence Tomography for the Differentiation of Renal Masses: a Pilot Cohort

      To view the full text, please login as a subscribed user or purchase a subscription . Click here to view the full text on ScienceDirect. The aim of this study is to determine the ability of percutaneous needle based Optical Coherence Tomography (OCT) to differentiate renal masses, by using the attenuation coefficient (μOCT, mm-1) as a quantitative measure. Percutaneous needle based OCT of the kidney was performed in patients presenting with a solid renal mass.

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    8. Learning curve and interobserver variance in quantification of the optical coherence tomography attenuation coefficient

      Learning curve and interobserver variance in quantification of the optical coherence tomography attenuation coefficient

      The learning curve and interobserver variance of attenuation coefficient ( μ OCT ) determination from optical coherence tomography (OCT) images were quantified. The μ OCT of normal and diseased vulvar tissues was determined at five time points by three novice students and three OCT experts who reached consensus for reference. Students received feedback between time points. Eventually, variance in μ OCT was smaller in images of diseased tissue than in images of normal vulvar tissue. The difference between the consensus and student μ OCT values was larger for smaller values of μ OCT . We conclude that routine μ OCT determination for tissue classification does not require extensive training.

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    9. Assesment of apoptosis induced changes in scattering using optical coherence tomography

      Assesment of apoptosis induced changes in scattering using optical coherence tomography

      The aim of this study is to identify changes in scattering with optical coherence tomography (OCT) and relate these measurements with mitochondrial changes during the initiation of apoptosis. Human retinal pigment epithelial cells were cultured and apoptosis was induced using 10% alcohol. Using the attenuation coefficient and backscattering, changes were measured during cell death in a cell-pellet and monolayer respectively. To confirm apoptosis, fluorescent activated cell sorting was used. Mitochondrial activity during apoptosis was assessed using an oxidative stress assay and fluorescent confocal microscopy. Pelleted apoptotic cells measured with OCT showed a clear rise while untreated cells showed a very ...

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    10. Optical coherence tomography accurately identifies patients with penile (pre) malignant lesions: A single center prospective study

      Optical coherence tomography accurately identifies patients with penile (pre) malignant lesions: A single center prospective study

      Introduction: Currently, (multiple) biopsies are taken to obtain histopathological diagnosis of suspicious lesions of the penile skin. Optical coherence tomography (OCT) provides noninvasive in vivo images from which epidermal layer thickness and attenuation coefficient (m oct ) can be quantified. We hypothesize that qualitative (image assessment) and quantitative (epidermal layer thickness and attenuation coefficient, m oct ) analysis of penile skin with OCT is possible and may differentiate benign penile tissue from (pre) malignant penile tissue. Materials and Methods: Optical coherence tomography-imaging was performed prior to punch biopsy in 18 consecutive patients with a suspicious lesion at the outpatient clinic of the ...

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    11. Prostate cancer diagnosis: the feasibility of needle-based optical coherence tomography

      Prostate cancer diagnosis: the feasibility of needle-based optical coherence tomography

      The objective of this study is to demonstrate the feasibility of needle-based optical coherence tomography (OCT) and functional analysis of OCT data along the full pullback trajectory of the OCT measurement in the prostate, correlated with pathology. OCT images were recorded using a commercially available C7-XR™ OCT Intravascular Imaging System interfaced to a C7 Dragonfly™ intravascular 0.9-mm-diameter imaging probe. A computer program was constructed for automated image attenuation analysis. First, calibration of the OCT system for both the point spread function and the system roll-off was achieved by measurement of the OCT signal attenuation from an extremely weakly scattering ...

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    12. Detection of buried Barrett’s glands after radiofrequency ablation with volumetric laser endomicroscopy

      Detection of buried Barrett’s glands after radiofrequency ablation with volumetric laser endomicroscopy

      Background and Aims The prevalence and clinical relevance of buried Barrett’s glands (BB) after radiofrequency ablation (RFA) in Barrett’s esophagus (BE) are debated. Recent optical coherence tomography studies demonstrated a high prevalence of BBs. Direct histological correlation, however, has been lacking. Volumetric laser endomicroscopy (VLE) is a second-generation optical coherence tomography system capable of scanning a large surface of the esophageal wall layers with low-power microscopy resolution. The aim was to evaluate whether post-RFA subsquamous glandular structures (SGSs), detected with VLE, actually correspond to BBs by pursuing direct histological correlation with VLE images. Methods In vivo VLE was ...

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    13. In Vivo, Percutaneous, Needle Based, Optical Coherence Tomography of Renal Masses

      In Vivo, Percutaneous, Needle Based, Optical Coherence Tomography of Renal Masses

      Optical coherence tomography (OCT) is the optical equivalent of ultrasound imaging, based on the backscattering of near infrared light. OCT provides real time images with a 15 µm axial resolution at an effective tissue penetration of 2-3 mm. Within the OCT images the loss of signal intensity per millimeter of tissue penetration, the attenuation coefficient, is calculated. The attenuation coefficient is a tissue specific property, providing a quantitative parameter for tissue differentiation. Until now, renal mass treatment decisions have been made primarily on the basis of MRI and CT imaging characteristics, age and comorbidity. However these parameters and diagnostic methods ...

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    14. Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Purpose To assess the effect of media opacities on thickness measurements of the peripapillary retinal nerve fibre layer (pRNFL) and macular inner retinal layer (mIRL) performed with spectral-domain optical coherence tomography (SD-OCT) using a set of filters with known optical density. Methods Spectral-domain optical coherence tomography volume scans of the optic disc and the macular area were performed in 18 healthy volunteers, using Topcon-3DOCT-1000 Mark II. A set of five filters with optical density ranging from 0.04 to 0.69 was used. The correlation was calculated between the percentage change in thickness measurements (%ΔpRNFL and %ΔmIRL) and the change ...

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    15. The Value of Optical Coherence Tomography in Determining Surgical Margins in Squamous Cell Carcinoma of the Vulva: A Single-Center Prospective Study.

      The Value of Optical Coherence Tomography in Determining Surgical Margins in Squamous Cell Carcinoma of the Vulva: A Single-Center Prospective Study.

      Background: Vulvar squamous cell carcinoma (VSCC) is treated with wide local excision. The challenge is to remove as much skin as necessary to prevent recurrence, but meanwhile preserve genital skin to diminish morbidity. Optical coherence tomography (OCT) is a noninvasive imaging tool that produces cross-sectional images. Optical coherence tomography could be helpful in determining appropriate surgical margins during excision of VSCC. Objective: This study aimed to assess the value of OCT in determining appropriate surgical margins in patients operated for VSCC. We hypothesize that benign tissue will differ qualitatively (presence of clear epidermal layers) and quantitatively (epidermal layer thickness and ...

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    16. Comparison of optical coherence tomography and histopathology in quantitative assessment of goat talus articular cartilage

      Comparison of optical coherence tomography and histopathology in quantitative assessment of goat talus articular cartilage

      Background and purpose — Optical coherence tomography (OCT) is a light-based imaging technique suitable for depiction of thin tissue layers such as articular cartilage. Quantification of results and direct comparison with a reference standard is needed to confirm the role of OCT in cartilage evaluation. Materials and methods — Goat talus articular cartilage repair was assessed quantitatively with OCT and compared with histopathology using semi-automated analysis software. Osteochondral defects were created centrally in goat tali with subsequent healing over 24 weeks. After sacrifice, the tali were analyzed using OCT and processed into histopathology slides. Cartilage thickness, repair tissue area, and surface roughness ...

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    17. Optical diagnostics for Upper Urinary Tract Urothelial cancer: technology, thresholds and clinical applications

      Optical diagnostics for Upper Urinary Tract Urothelial cancer: technology, thresholds and clinical applications

      Purpose: Developments in optical diagnostics have potential for less invasive diagnose of upper urinary tract urothelial carcinoma (UUT-UC). This systematic review provides an overview of technology, applications and limitations of recently developed optical diagnostics in the upper urinary tract and outlines their potential for future clinical applications. In addition, current evidence was evaluated. Literature search: A PubMed literature search was performed and papers on Narrow Band Imaging (NBI), Photodynamic Diagnosis (PDD), Storz Professional Imaging Enhancement System (SPIES), Optical Coherence Tomography (OCT) and Confocal Laser Endomicroscopy (CLE) regarding UUT-UC were reviewed for data extraction. Study quality was reviewed according to QUADAS ...

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    18. Quantitative comparison of analysis methods for spectroscopic optical coherence tomography: reply to comment

      Quantitative comparison of analysis methods for spectroscopic optical coherence tomography: reply to comment

      We reply to the comment by Kraszewski et al on “Quantitative comparison of analysis methods for spectroscopic optical coherence tomography.” We present additional simulations evaluating the proposed window function. We conclude that our simulations show good qualitative agreement with the results of Kraszewski, in support of their conclusion that SOCT optimization should include window shape, next to choice of window size and analysis algorithm.

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    19. Feature Of The Week 11/10/13: Volumetric In-Vivo Visualization of Upper Urinary Tract Tumors Using Optical Coherence Tomography: A Pilot Study

      Feature Of The Week 11/10/13: Volumetric In-Vivo Visualization of Upper Urinary Tract Tumors Using Optical Coherence Tomography: A Pilot Study

      Optical Coherence Tomography (OCT) has proven a powerful tool for ophthalmologists to make clinical decisions for a wide range of blinding diseases and the there are now ~20 million ophthalmic OCT patient scans per year. Significant progress is also being made in intravascular imaging where OCT is emerging as a tool for both clinical decision making and the understanding of cardiovascular disease and development of new therapeutic tools. OCT also has the potential to impact the understanding, diagnosis, and treatment of some forms of cancer. There are many leading research groups around the world that are making excellent progress in ...

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    20. Quantitative comparison of analysis methods for spectroscopic optical coherence tomography

      Quantitative comparison of analysis methods for spectroscopic optical coherence tomography

      Spectroscopic optical coherence tomography (sOCT) enables the mapping of chromophore concentrations and image contrast enhancement in tissue. Acquisition of depth resolved spectra by sOCT requires analysis methods with optimal spectral/spatial resolution and spectral recovery. In this article, we quantitatively compare the available methods, i.e. the short time Fourier transform (STFT), wavelet transforms, the Wigner-Ville distribution and the dual window method through simulations in tissue-like media. We conclude that all methods suffer from the trade-off in spectral/spatial resolution, and that the STFT is the optimal method for the specific application of the localized quantification of hemoglobin concentration and ...

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    21. Optical coherence tomography in vulvar intraepithelial neoplasia

      Optical coherence tomography in vulvar intraepithelial neoplasia

      Vulvar squamous cell carcinoma (VSCC) is a gynecological cancer with an incidence of two to three per 100,000 women. VSCC arises from vulvar intraepithelial neoplasia (VIN), which is diagnosed through painful punch biopsy. In this study, optical coherence tomography (OCT) is used to differentiate between normal and VIN tissue. We hypothesize that (a) epidermal layer thickness measured in OCT images is different in normal tissue and VIN, and (b) quantitative analysis of the attenuation coefficient ( μ oct ) extracted from OCT data differentiates VIN from normal vulvar tissue. Twenty lesions from 16 patients are imaged with OCT. Directly after data acquisition ...

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    22. Feature Of The Week 9/2/12: Academic Medical Center at The University of Amsterdam Investigates Comparison of RNFL Thickness Measurements by SD-OCT Systems Using a Phantom Eye Model

      Feature Of The Week 9/2/12: Academic Medical Center at The University of Amsterdam Investigates Comparison of RNFL Thickness Measurements by SD-OCT Systems Using a Phantom Eye Model

      We developed a multi-layered phantom eye model that distinguishes instrumental from biological variation, to quantify differences in retinal nerve fiber layer (RNFL) thickness measurements by various spectral-domain optical coherence tomography (SD-OCT) systems. The eye model comprised a glass lens, water as vitreous and silicone elastomer based layers mimicking the retina (top layer thickness = 49 µm). We tested 3 RTVue OptoVue, 3 Cirrus Zeiss, 3 3DOCT-1000 Topcon and 3 Spectralis Heidelberg SD-OCT systems. With each system the layered phantom eye model was measured 5 times. An average RNFL thickness and standard deviation were determined by the apparatus using a circular scan ...

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    23. Spectral domain detection in low-coherence spectroscopy

      Spectral domain detection in low-coherence spectroscopy

      Low-coherence spectroscopy (LCS) offers the valuable possibility to measure quantitative and wavelength resolved optical property spectra within a tissue volume of choice that is controllable both in size and in depth. Until now, only time domain detection was investigated for LCS (tdLCS), but spectral domain detection offers a theoretical speed/sensitivity advantage over tdLCS. In this article, we introduce a method for spectral domain detection in LCS (sdLCS), with optimal sensitivity as a function of measurement depth. We validate our method computationally in a simulation and experimentally on a phantom with known optical properties. The attenuation, absorption and scattering coefficient ...

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    24. Comparison of retinal nerve fiber layer thickness measurements by spectral-domain optical coherence tomography systems using a phantom eye model

      Comparison of retinal nerve fiber layer thickness measurements by spectral-domain optical coherence tomography systems using a phantom eye model

      To quantify differences in nerve fiber layer thickness measurements by various spectral-domain optical coherence tomography (SD-OCT) systems, we developed a phantom eye model. We tested twelve SD-OCT systems of four manufacturers. All systems combined overestimated the 49 µm thick phantom RNFL thickness on average by 18 µm. Within brands, thickness measurements differed statistically significant for one Topcon, one RTVue and one Cirrus. Between brands, thickness determined with RTVue and Topcon differed statistically significant from Cirrus and Spectralis. The maximum difference between mean thicknesses is 3.6 µm within brands and 7.7 µm between brands.

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    1-24 of 35 1 2 »
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    1. (35 articles) Dirk J. Faber
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    3. (31 articles) Academic Medical Center at the University of Amsterdam
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    Quantitative measurement of attenuation coefficients of bladder biopsies using optical coherence tomography for grading urothelial carcinoma of the bladder Integrated system for combined Raman spectroscopy–spectral domain optical coherence tomography Advanced Diagnostics in Renal Mass Using Optical Coherence Tomography: A Preliminary Report Measurements of wavelength dependent scattering and backscattering coefficients by low-coherence spectroscopy Heartbeat-induced axial motion artifacts in optical coherence tomography measurements of the retina Comparison of retinal nerve fiber layer thickness measurements by spectral-domain optical coherence tomography systems using a phantom eye model Feature Of The Week 9/2/12: Academic Medical Center at The University of Amsterdam Investigates Comparison of RNFL Thickness Measurements by SD-OCT Systems Using a Phantom Eye Model Feature Of The Week 11/10/13: Volumetric In-Vivo Visualization of Upper Urinary Tract Tumors Using Optical Coherence Tomography: A Pilot Study A patient with multiple Swiss cheese aspect coronary lesions: optical coherence tomography to guide coronary angioplasty Preoperative spectral-domain optical coherence tomography in cataract surgery Changes in retinal vasculature after phacoemulsification evaluated using optical coherence tomography angiography Monitoring Acute Stroke in Mouse Model Using Laser Speckle Imaging-Guided Visible-Light Optical Coherence Tomography