1. Articles from Amy L. Oldenburg

    1-24 of 43 1 2 »
    1. Post-doctoral Scholar Position in OCT Endoscopy at the University of North Carolina at Chapel Hill

      Post-doctoral Scholar Position in OCT Endoscopy at the University of North Carolina at Chapel Hill

      The Coherence Imaging Laboratory at the University of North Carolina at Chapel Hill seeks a highly motivated Postdoc to perform research in optical coherence tomography (OCT) imaging. Research activities will include the development and application of our endoscopic OCT imaging systems for upper airway imaging, and its application for assessment of airway injury and upper airway disorders. Candidates are required to have demonstrated expertise with imaging hardware and hardware design, with particular consideration given to candidates with experience using fiber optics, fabricating fiber optic tips, using and setting up interferometers or similar optical systems, and setting up data acquisition systems ...

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    2. Tracking the invasion of breast cancer cells in paper-based 3D cultures by OCT motility analysis

      Tracking the invasion of breast cancer cells in paper-based 3D cultures by OCT motility analysis

      3D paper-based cultures (PBCs) are easy-to-use and provide a biologically representative microenvironment. By stacking a sheet of cell-laden paper below sheets containing cell-free hydrogel, we form an assay capable of segmenting cells by the distance they invaded from the original cell-seeded layer. These invasion assays are limited to end-point analyses with fluorescence-based readouts due to the highly scattering nature of the paper scaffolds. Here we demonstrate that optical coherence tomography (OCT) can distinguish living cells from the surrounding extracellular matrix (ECM) or paper fibers based upon their intracellular motility amplitude ( M ). M is computed from fluctuation statistics of the sample ...

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    3. Utility of endoscopic anatomical optical coherence tomography in functional rhinoplasty

      Utility of endoscopic anatomical optical coherence tomography in functional rhinoplasty

      Objective measurement of the nasal valve region is valuable for the assessment of functional rhinoplasty surgical outcomes. Anatomical optical coherence tomography (aOCT) is an imaging modality that may be used to obtain real-time, quantitative, and volumetric scans of the nasal airway. We aim to evaluate if volumetric aOCT imaging is useful for the examination of the nasal valve region before and after functional rhinoplasty procedures. aOCT scans of the nasal valves were performed on four cadaveric heads before and after spreader graft and butterfly graft procedures. The resulting aOCT images were compared against video endoscopy images, and the segmented volumes ...

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      Mentions: Amy L. Oldenburg
    4. Characterizing optical coherence tomography speckle fluctuation spectra of mammary organoids during suppression of intracellular motility

      Characterizing optical coherence tomography speckle fluctuation spectra of mammary organoids during suppression of intracellular motility

      Background: An understanding of how the mammary gland responds to toxicant and drug exposures can shed light on mechanisms of breast cancer initiation/progression and therapeutic effectiveness, respectively. In this study, we employed noninvasive, label-free and high-throughput optical coherence tomography speckle fluctuation spectroscopy (OCT-SFS) to track exposure-response relationships in three-dimensional (3D) mammary epithelial organoid models. Methods: OCT-SFS is sensitive to relatively high speed (~0.16–8 µm/min) motions of subcellular light scattering components occurring over short (~2–114 s) time scales, termed “intracellular motility.” In this study, OCT speckle fluctuation spectra are quantified by two metrics: the intracellular motility ...

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    5. Localized compliance measurement of the airway wall using anatomic optical coherence elastography

      Localized compliance measurement of the airway wall using anatomic optical coherence elastography

      We describe an elastographic method to circumferentially-resolve airway wall compliance using endoscopic, anatomic optical coherence tomography (aOCT) combined with an intraluminal pressure catheter. The method was first demonstrated on notched silicone phantoms of known elastic modulus under respiratory ventilation, where localized compliance measurements were validated against those predicted by finite element modeling. Then, ex vivo porcine tracheas were scanned, and the pattern of compliance was found to be consistent with histological identification of the locations of (stiff) cartilage and (soft) muscle. This quantitative method may aid in diagnosis and monitoring of collapsible airway wall tissues in obstructive respiratory disorders.

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    6. Geometric Validation of Continuous, Finely Sampled 3-D Reconstructions From aOCT and CT in Upper Airway Models

      Geometric Validation of Continuous, Finely Sampled 3-D Reconstructions From aOCT and CT in Upper Airway Models

      Identification and treatment of obstructive airway disorders (OADs) are greatly aided by imaging of the geometry of the airway lumen. Anatomical optical coherence tomography (aOCT) is a promising high-speed and minimally invasive endoscopic imaging modality for providing micrometer-resolution scans of the upper airway. Resistance to airflow in OADs is directly caused by the reduction in luminal cross-sectional area (CSA). It is hypothesized that aOCT can produce airway CSA measurements as accurate as that from computed tomography (CT). Scans of machine hollowed cylindrical tubes were used to develop methods for segmentation and measurement of airway lumen in CT and aOCT. Simulated ...

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    7. Combined anatomical optical coherence tomography and intraluminal pressure reveal viscoelasticity of the in vivo airway

      Combined anatomical optical coherence tomography and intraluminal pressure reveal viscoelasticity of the in vivo airway

      It is hypothesized that the local, viscoelastic (time-dependent) properties of the airway are important to accurately model and ultimately predict dynamic airway collapse in airway obstruction. Toward this end, we present a portable, endoscopic, swept-source anatomical optical coherence tomography (aOCT) system combined with a pressure catheter to capture local airway dynamics in vivo during respiration. aOCT scans were performed in the airways of a mechanically ventilated pig under paralysis with dynamic and static ventilation protocols. Validation of dynamic aOCT luminal cross-sectional area (CSA) measurements against Cine CT, obtained during the same exam, showed an aggregate difference of 15  %    ±  3  %  . aOCT-derived ...

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    8. Geometric Validation of Continuous, Finely-Sampled 3D Reconstructions from aOCT and CT in Upper Airway Models

      Geometric Validation of Continuous, Finely-Sampled 3D Reconstructions from aOCT and CT in Upper Airway Models

      Identification and treatment of obstructive airway disorders (OADs) is greatly aided by imaging of the geometry of the airway lumen. Anatomical optical coherence tomography (aOCT) is a promising high-speed and minimally-invasive endoscopic imaging modality for providing micrometer-resolution scans of the upper airway. Resistance to airflow in OADs is directly caused by reduction in luminal cross-sectional area (CSA). It is hypothesized that aOCT can produce airway CSA measurements as accurate as that from computed tomography (CT). Scans of machine hollowed cylindrical tubes were used to develop methods for segmentation and measurement of airway lumen in CT and aOCT. Simulated scans of ...

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    9. Quantification of the Effect of Toxicants on the Intracellular Kinetic Energy and Cross-Sectional Area of Mammary Epithelial Organoids by OCT Fluctuation Spectroscopy

      Quantification of the Effect of Toxicants on the Intracellular Kinetic Energy and Cross-Sectional Area of Mammary Epithelial Organoids by OCT Fluctuation Spectroscopy

      The ability to assess toxicant exposures of 3D in vitro mammary models that recapitulate the tissue microenvironment can aid in our understanding of environmental exposure risk over time. Longitudinal studies of 3D model systems, however, are cumbersome and suffer from a lack of high-throughput toxicological assays. In this study, we establish a noninvasive and label-free optical coherence tomography (OCT)-based imaging platform for tracking exposure-response relationships in 3D human mammary epithelial organoid models. The OCT-based assay includes metrics that quantify organoid intracellular kinetic energy and cross-sectional area (CSA). We compare the results to those obtained using the 3-(4,5-dimethylthiazol-2-yl ...

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    10. Diffusion tensor optical coherence tomography

      Diffusion tensor optical coherence tomography

      In situ measurements of diffusive particle transport provide insight into tissue architecture, drug delivery, and cellular function. Analogous to diffusion-tensor magnetic resonance imaging (DT-MRI), where the anisotropic diffusion of water molecules is mapped on the millimeter scale to elucidate the fibrous structure of tissue, here we propose diffusion-tensor optical coherence tomography (DT-OCT) for measuring directional diffusivity and flow of optically scattering particles within tissue. Because DT-OCT is sensitive to the sub-resolution motion of Brownian particles as they are constrained by tissue macromolecules, it has the potential to quantify nanoporous anisotropic tissue structure at micrometer resolution as relevant to extracellular matrices ...

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    11. Feature of the Week 05/14/2017: Real-Time Monitoring of Mucus Thinning Treatments using Diffusion-Sensitive Optical Coherence Tomography

      Feature of the Week 05/14/2017: Real-Time Monitoring of Mucus Thinning Treatments using Diffusion-Sensitive Optical Coherence Tomography

      The airway epithelium is coated with a biopolymeric mucus gel which is responsible for trapping inhaled environmental contaminants that are subsequently removed by mucociliary clearance (MCC). MCC is disrupted under high mucus wt%, causing mucus stagnation, chronic infection and inflammation. Normal mucus hydration by the epithelium is impaired in cystic fibrosis (CF) and COPD resulting in high mucus wt% that leads to halted MCC. Hypertonic saline (HS) treatment is a therapeutic approach to reduce mucus wt% for sustained MCC that has gained popularity due to its relative safety, easy administration, and low cost. However, patient to patient variability, conflicting therapeutic ...

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    12. Airway compliance measured by anatomic optical coherence tomography

      Airway compliance measured by anatomic optical coherence tomography

      Quantification of airway compliance can aid in the diagnosis and treatment of obstructive airway disorders by detecting regions vulnerable to collapse. Here we evaluate the ability of a swept-source anatomic optical coherence tomography (SSaOCT) system to quantify airway cross-sectional compliance (CC) by measuring changes in the luminal cross-sectional area (CSA) under physiologically relevant pressures of 10–40 cmH 2 O. The accuracy and precision of CC measurements are determined using simulations of non-uniform rotation distortion (NURD) endemic to endoscopic scanning, and experiments performed in a simplified tube phantom and ex vivo porcine tracheas. NURD simulations show that CC measurements are ...

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    13. Multi-modal anatomical optical coherence tomography and CT for in vivo dynamic upper airway imaging

      Multi-modal anatomical optical coherence tomography and CT for in vivo dynamic upper airway imaging

      We describe a novel, multi-modal imaging protocol for validating quantitative dynamic airway imaging performed using anatomical Optical Coherence Tomography (aOCT). The aOCT system consists of a catheter-based aOCT probe that is deployed via a bronchoscope, while a programmable ventilator is used to control airway pressure. This setup is employed on the bed of a Siemens Biograph CT system capable of performing respiratory-gated acquisitions. In this arrangement the position of the aOCT catheter may be visualized with CT to aid in co-registration. Utilizing this setup we investigate multiple respiratory pressure parameters with aOCT, and respiratory-gated CT, on both ex vivo porcine ...

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    14. High-speed and high-sensitivity parallel spectral-domain optical coherence tomography using a supercontinuum light source

      High-speed and high-sensitivity parallel spectral-domain optical coherence tomography using a supercontinuum light source

      The three most important metrics in optical coherence tomography (OCT) are resolution, speed, and sensitivity. Because there is a complex interplay between these metrics, no previous work has obtained the best performance in all three metrics simultaneously. We demonstrate that a high-power supercontinuum source, in combination with parallel spectral-domain OCT, achieves an unparalleled combination of resolution, speed, and sensitivity. This system captures cross-sectional images spanning 4    mm × 0.5    mm 4  mm×0.5  mm at 1,024,000 lines/s with 2 × 14    μm 2×14  μm resolution ( axial × transverse axial×transverse ) at a sensitivity of 113 dB. Imaging ...

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    15. Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography

      Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography

      Optical coherence tomography (OCT) has gained widespread application for many biomedical applications, yet the traditional array of contrast agents used in incoherent imaging modalities do not provide contrast in OCT. Owing to the high biocompatibility of iron oxides and noble metals, magnetic and plasmonic nanoparticles, respectively, have been developed as OCT contrast agents to enable a range of biological and pre-clinical studies. Here, we provide a review of these developments within the past decade, including an overview of the physical contrast mechanisms and classes of OCT system hardware add-ons needed for magnetic and plasmonic nanoparticle contrast . A comparison of the ...

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    16. Imaging Extracellular Matrix Remodeling In Vitro by Diffusion-Sensitive Optical Coherence Tomography

      Imaging Extracellular Matrix Remodeling In Vitro by Diffusion-Sensitive Optical Coherence Tomography

      The mammary gland extracellular matrix (ECM) is comprised of biopolymers, primarily collagen I, that are created and maintained by stromal fibroblasts. ECM remodeling by fibroblasts results in changes in ECM fiber spacing (pores) that have been shown to play a critical role in the aggressiveness of breast cancer. However, minimally invasive methods to measure the spatial distribution of ECM pore areas within tissues and in vitro 3D culture models are currently lacking. We introduce diffusion-sensitive optical coherence tomography (DS-OCT) to image the nanoscale porosity of ECM by sensing weakly constrained diffusion of gold nanorods (GNRs). DS-OCT combines the principles of ...

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    17. Swept-source anatomic optical coherence elastography of porcine trachea

      Swept-source anatomic optical coherence elastography of porcine trachea

      Quantitative endoscopic imaging is at the vanguard of novel techniques in the assessment upper airway obstruction. Anatomic optical coherence tomography (aOCT) has the potential to provide the geometry of the airway lumen with high-resolution and in 4 dimensions. By coupling aOCT with measurements of pressure, optical coherence elastography (OCE) can be performed to characterize airway wall stiffness. This can aid in identifying regions of dynamic collapse as well as informing computational fluid dynamics modeling to aid in surgical decision-making. Toward this end, here we report on an anatomic optical coherence tomography (aOCT) system powered by a wavelength-swept laser source. The ...

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    18. Diffusion-sensitive optical coherence tomography for real-time monitoring of mucus thinning treatments

      Diffusion-sensitive optical coherence tomography for real-time monitoring of mucus thinning treatments

      Mucus hydration (wt%) has become an increasingly useful metric in real-time assessment of respiratory health in diseases like cystic fibrosis and COPD, with higher wt% indicative of diseased states. However, available in vivo rheological techniques are lacking. Gold nanorods (GNRs) are attractive biological probes whose diffusion through tissue is sensitive to the correlation length of comprising biopolymers. Through employment of dynamic light scattering theory on OCT signals from GNRs, we find that weakly-constrained GNR diffusion predictably decreases with increasing wt% (more disease-like) mucus. Previously, we determined this method is robust against mucus transport on human bronchial epithelial (hBE) air-liquid interface ...

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    19. Post Doctoral Position Opening at The Coherence Imaging Laboratory at the University of North Carolina at Chapel Hill

      Post Doctoral Position Opening at The Coherence Imaging Laboratory at the University of North Carolina at Chapel Hill

      The Coherence Imaging Laboratory at the University of North Carolina at Chapel Hill seeks a highly motivated Postdoc to perform research in ultrahigh-resolution optical coherence tomography (UHR-OCT). Research activities will involve optical system construction and data acquisition hardware and software. They will also involve biological studies of cells and tissues primarily related to our lab's ongoing efforts in Marine Biology. Candidates with a strong background in optics and data acquisition are particularly sought, but should also demonstrate a genuine interest in biological and biomedical science. A demonstrated record of publication in peer-reviewed journals is required to be competitive for ...

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    20. Probing biological nanotopology via diffusion of weakly constrained plasmonic nanorods with optical coherence tomography

      Probing biological nanotopology via diffusion of weakly constrained plasmonic nanorods with optical coherence tomography

      Biological materials exhibit complex nanotopology , i.e., a composite liquid and solid phase structure that is heterogeneous on the nanoscale. The diffusion of nanoparticles in nanotopological environments can elucidate biophysical changes associated with pathogenesis and disease progression. However, there is a lack of methods that characterize nanoprobe diffusion and translate easily to in vivo studies. Here, we demonstrate a method based on optical coherence tomography (OCT) to depth-resolve diffusion of plasmon-resonant gold nanorods (GNRs) that are weakly constrained by the biological tissue. By using GNRs that are on the size scale of the polymeric mesh, their Brownian motion is minimally ...

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    21. Quantitative upper airway endoscopy with swept-source anatomical optical coherence tomography

      Quantitative upper airway endoscopy with swept-source anatomical optical coherence tomography

      Minimally invasive imaging of upper airway obstructions in children and adults is needed to improve clinical decision-making. Toward this goal, we demonstrate an anatomical optical coherence tomography (aOCT) system delivered via a small-bore, flexible endoscope to quantify the upper airway lumen geometry. Helical scans were obtained from a proximally-scanned fiber-optic catheter of 820 μm outer diameter and >2 mm focal length. Coupled with a long coherence length wavelength-swept light source, the system exhibited an SNR roll-off of < 10 dB over a 10 mm range. Operating at 10 rotations/s, the average accuracy of segmented cross-sectional areas was found to be ...

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    22. Motility-, autocorrelation-, and polarization-sensitive optical coherence tomography discriminates cells and gold nanorods within 3D tissue cultures

      Motility-, autocorrelation-, and polarization-sensitive optical coherence tomography discriminates cells and gold nanorods within 3D tissue cultures

      We propose a method for differentiating classes of light scatterers based upon their temporal and polarization properties computed from time series of polarization-sensitive optical coherence tomography (PS-OCT) images. The amplitude (motility) and time scale (autocorrelation decay time) of the speckle fluctuations are combined with the cross-polarization pixel-wise to render Motility-, autocorrelation-, and polarization-sensitive (MAPS) OCT contrast images. This combination of metrics provides high specificity for discriminating diffusive gold nanorods and mammary epithelial cell spheroids within 3D tissue culture, based on their unique MAPS signature. This has implications toward highly specific contrast in molecular (nanoparticle-based) and functional (cellular activity) imaging using ...

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    23. Feature Of The Week 2/24/13: University of North Carolina uses OCT To Study Breast Cancer Morphology

      Feature Of The Week 2/24/13: University of North Carolina uses OCT To Study Breast Cancer Morphology

      The human mammary gland is a complex and heterogeneous organ, where the interactions between mammary epithelial cells (MEC) and stromal fibroblasts are known to regulate normal biology and tumorigenesis. We aimed to longitudinally evaluate morphology and size of organoids in 3D co-cultures of normal (MCF10A) or pre-malignant (MCF10DCIS.com) MEC and hTERT-immortalized fibroblasts from reduction mammoplasty (RMF). This co-culture model, based on an isogenic panel of cell lines, can yield insights to understand breast cancer progression. However, 3D cultures pose challenges for quantitative assessment and imaging, especially when the goal is to measure the same organoid structures over time. Using ...

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    24. Longitudinal Study of Mammary Epithelial and Fibroblast Co-Cultures Using Optical Coherence Tomography Reveals Morphological Hallmarks of Pre-Malignancy

      Longitudinal Study of Mammary Epithelial and Fibroblast Co-Cultures Using Optical Coherence Tomography Reveals Morphological Hallmarks of Pre-Malignancy

      The human mammary gland is a complex and heterogeneous organ, where the interactions between mammary epithelial cells (MEC) and stromal fibroblasts are known to regulate normal biology and tumorigenesis. We aimed to longitudinally evaluate morphology and size of organoids in 3D co-cultures of normal (MCF10A) or pre-malignant (MCF10DCIS.com) MEC and hTERT-immortalized fibroblasts from reduction mammoplasty (RMF). This co-culture model, based on an isogenic panel of cell lines, can yield insights to understand breast cancer progression. However, 3D cultures pose challenges for quantitative assessment and imaging, especially when the goal is to measure the same organoid structures over time. Using ...

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    1-24 of 43 1 2 »
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    1. (43 articles) Amy L. Oldenburg
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