1. Articles from nienke bosschaart

    1-9 of 9
    1. Spatially confined quantification of bilirubin concentrations by spectroscopic visible-light optical coherence tomography

      Spatially confined quantification of bilirubin concentrations by spectroscopic visible-light optical coherence tomography

      Spatially confined measurements of bilirubin in tissue can be of great value for noninvasive bilirubin estimations during neonatal jaundice, as well as our understanding of the physiology behind bilirubin extravasation. This work shows the potential of spectroscopic visible-light optical coherence tomography (sOCT) for this purpose. At the bilirubin absorption peak around 460 nm, sOCT suffers from a strong signal decay with depth, which we overcome by optimizing our system sensitivity through a combination of zero-delay acquisition and focus tracking. In a phantom study, we demonstrate the quantification of bilirubin concentrations between 0 and 650 µM with only a 10% difference ...

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    2. 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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    3. 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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    4. 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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    5. 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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    6. In vivo low-coherence spectroscopic measurements of local hemoglobin absorption spectra in human skin

      In vivo low-coherence spectroscopic measurements of local hemoglobin absorption spectra in human skin
      Localized spectroscopic measurements of optical properties are invaluable for diagnostic applications that involve layered tissue structures, but conventional spectroscopic techniques lack exact control over the size and depth of the probed tissue volume. We show that low-coherence spectroscopy (LCS) overcomes these limitations by measuring local attenuation and absorption coefficient spectra in layered phantoms. In addition, we demonstrate the first in vivo LCS measurements of the human epidermis and dermis only. From the measured absorption in two distinct regions of the dermal microcirculation, we determine total hemoglobin concentration (3.0±0.5 g/l and 7.8±1.2 g/l ...
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    7. Optical properties of neonatal skin measured in vivo as a function of age and skin pigmentation

      Optical properties of neonatal skin measured in vivo as a function of age and skin pigmentation
      Knowledge of the optical properties of neonatal skin is invaluable when developing new, or improving existing optical techniques for use at the neonatal intensive care. In this article, we present in vivo measurements of the absorption μa and reduced scattering coefficient μs′ of neonatal skin between 450 and 600 nm and assess the influence of age and skin pigmentation on the optical properties. The optical properties were measured using a spatially resolved, steady state diffuse reflectance spectroscopy setup, combined with a modified spatially resolved diffusion model. The method was validated on phantoms with known values for the absorption and reduced ...
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    8. Measurements of wavelength dependent scattering and backscattering coefficients by low-coherence spectroscopy

      Measurements of wavelength dependent scattering and backscattering coefficients by low-coherence spectroscopy
      Quantitative measurements of scattering properties are invaluable for optical techniques in medicine. However, noninvasive, quantitative measurements of scattering properties over a large wavelength range remain challenging. We introduce low-coherence spectroscopy as a noninvasive method to locally and simultaneously measure scattering μs and backscattering μb coefficients from 480 to 700 nm with 8 nm spectral resolution. The method is tested on media with varying scattering properties (μs = 1 to 34 mm−1 and μb = 2.10−6 to 2.10−3 mm−1), containing different sized polystyrene spheres. The results are in excellent agreement with Mie theory.
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    9. Combined Raman spectroscopy and optical coherence tomography device for tissue characterization

      Combined Raman spectroscopy and optical coherence tomography device for tissue characterization

      We report a dual-modal device capable of sequential acquisition of Raman spectroscopy (RS) and optical coherence tomography (OCT) along a common optical axis. The device enhances application of both RS and OCT by precisely guiding RS acquisition with OCT images while also compensating for the lack of molecular specificity in OCT with the biochemical specificity of RS. We characterize the system performance and demonstrate the capability to identify structurally ambiguous features within an OCT image with RS in a scattering phantom, guide acquisition of RS from a localized malignancy in ex vivo breast tissue, and perform in vivo tissue analysis ...

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    1-9 of 9
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  2. Topics in the News

    1. (8 articles) Ton G. van Leeuwen
    2. (8 articles) Nienke Bosschaart
    3. (7 articles) Academic Medical Center at the University of Amsterdam
    4. (6 articles) University of Twente
    5. (6 articles) Dirk J. Faber
    6. (1 articles) Vanderbilt University
    7. (1 articles) VU University Amsterdam
    8. (1 articles) Anita Mahadevan-Jansen
    9. (1 articles) Chetan A. Patil
    10. (1 articles) Massachusetts General Hospital
    11. (1 articles) Harvard University
    12. (1 articles) Guillermo J. Tearney
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    Combined Raman spectroscopy and optical coherence tomography device for tissue characterization Measurements of wavelength dependent scattering and backscattering coefficients by low-coherence spectroscopy Optical properties of neonatal skin measured in vivo as a function of age and skin pigmentation In vivo low-coherence spectroscopic measurements of local hemoglobin absorption spectra in human skin Spectral domain detection in low-coherence spectroscopy Quantitative comparison of analysis methods for spectroscopic optical coherence tomography Quantitative comparison of analysis methods for spectroscopic optical coherence tomography: reply to comment Validation of quantitative attenuation and backscattering coefficient measurements by optical coherence tomography in the concentration-dependent and multiple scattering regime Spatially confined quantification of bilirubin concentrations by spectroscopic visible-light optical coherence tomography Imaging the Human Prostate Gland Using 1-μm-Resolution Optical Coherence Tomography In Vivo and Ex Vivo Microscopy: Moving Toward the Integration of Optical Imaging Technologies Into Pathology Practice Recognition of calcified neoatherosclerosis