1. Articles in category: Otolaryngology

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    1. Non-Invasive Optical Assessment of Viscosity of Middle Ear Effusions in Otitis Media

      Non-Invasive Optical Assessment of Viscosity of Middle Ear Effusions in Otitis Media

      In vivo Optical Coherence Tomography (OCT) image of a human tympanic membrane and Middle Ear Effusion (MEE) (top), with a CCD image of the tympanic membrane surface (inset). Below is the corresponding time-lapse M-mode OCT data acquired along the white dotted line over time, which can be analyzed to determine the Stokes–Einstein diffusion coefficient of the effusion. Eustachian tube dysfunction can cause fluid to collect within the middle ear cavity and form a middle ear effusion (MEE). MEEs can persist for weeks or months and cause hearing loss as well as speech and learning delays in young children. The ...

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    2. Non-invasive optical assessment of viscosity of middle ear effusions in otitis media

      Non-invasive optical assessment of viscosity of middle ear effusions in otitis media

      In vivo Optical Coherence Tomography (OCT) image of a human tympanic membrane and Middle Ear Effusion (MEE) (top), with a CCD image of the tympanic membrane surface (inset). Below is the corresponding time-lapse M-mode OCT data acquired along the white dotted line over time, which can be analyzed to determine the Stokes–Einstein diffusion coefficient of the effusion. Eustachian tube dysfunction can cause fluid to collect within the middle ear cavity and form a middle ear effusion (MEE). MEEs can persist for weeks or months and cause hearing loss as well as speech and learning delays in young children. The ...

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    3. Decalcification using ethylenediaminetetraacetic acid for clear microstructure imaging of cochlea through optical coherence tomography

      Decalcification using ethylenediaminetetraacetic acid for clear microstructure imaging of cochlea through optical coherence tomography

      The aim of this study was to analyze the effectiveness of decalcification using ethylenediaminetetraacetic acid (EDTA) as an optical clearing method to enhance the depth visibility of internal soft tissues of cochlea. Ex vivo mouse and guinea pig cochlea samples were soaked in EDTA solutions for decalcification, and swept source optical coherence tomography (OCT) was used as imaging modality to monitor the decalcified samples consecutively. The monitored noninvasive cross-sectional images showed that the mouse and guinea pig cochlea samples had to be decalcified for subsequent 7 and 14 days, respectively, to obtain the optimal optical clearing results. Using this method ...

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    4. Investigation of middle ear anatomy and function with combined video otoscopy-phase sensitive OCT

      Investigation of middle ear anatomy and function with combined video otoscopy-phase sensitive OCT

      We report the development of a novel otoscopy probe for assessing middle ear anatomy and function. Video imaging and phase-sensitive optical coherence tomography are combined within the same optical path. A sound stimuli channel is incorporated as well to study middle ear function. Thus, besides visualizing the morphology of the middle ear, the vibration amplitude and frequency of the eardrum and ossicles are retrieved as well. Preliminary testing on cadaveric human temporal bone models has demonstrated the capability of this instrument for retrieving middle ear anatomy with micron scale resolution, as well as the vibration of the tympanic membrane and ...

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    5. Optical coherence tomography imaging to analyze biofilm thickness from distal to proximal regions of the endotracheal tubes

      Optical coherence tomography imaging to analyze biofilm thickness from distal to proximal regions of the endotracheal tubes

      The development of nosocomial ventilator-associated pneumonia (VAP) has been linked to the presence of specific bacteria found in the biofilm that develops in intubated endotracheal tubes of critical care patients. Presence of biofilm has been difficult to assess clinically. Here, we use Optical coherence tomography (OCT), to visualize the biofilm at both the proximal and distal tips. Ultimately, the goal will be to determine if OCT can be a tool to visualize biofilm development and potential interventions to reduce the incidence of VAP.

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    6. 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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    7. Estimation of the Degree of Endolymphatic Hydrops Using Optical Coherence Tomography

      Estimation of the Degree of Endolymphatic Hydrops Using Optical Coherence Tomography

      Endolymphatic hydrops is a disorder in which an excessive amount of endolymph fluid causes an increase in the pressure of the endolymphatic system of the inner ear. In cochlea, endolymphatic hydrops can cause stretching in the scala media , a tubular construction that, along with two other similar structures, the scala vestibuli and scala tympani , runs through the cochlea from the base to the top. Visualizing the enlargement of the scala media has traditionally been done by histological study of tissue sections, and the degree can be calculated by comparing the ratio of the area of the scala media to the ...

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    8. Effect of saline inhalation on vocal fold epithelial morphology evaluated by optical coherence tomography

      Effect of saline inhalation on vocal fold epithelial morphology evaluated by optical coherence tomography

      Objectives/Hypothesis Examination of tissue structures by optical coherence tomography (OCT) has been shown to be useful on mucous membranes of the vocal folds, but so far its application to the human larynx has been limited because it is technically cumbersome and usually needs to be performed with sedation. Here a newly developed, noninvasive combined laryngoscopy and OCT procedure is described and its suitability for ambulatory OCT studies evaluated. Because inhalation therapies utilizing saline solutions are commonly used as a treatment option for disorders of the airways, and vocal fold epithelium is most likely to be affected due to its ...

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    9. In vivo cross-sectional imaging of the phonating larynx using long-range Doppler optical coherence tomography

      In vivo cross-sectional imaging of the phonating larynx using long-range Doppler optical coherence tomography

      Diagnosis and treatment of vocal fold lesions has been a long-evolving science for the otolaryngologist. Contemporary practice requires biopsy of a glottal lesion in the operating room under general anesthesia for diagnosis. Current in-office technology is limited to visualizing the surface of the vocal folds with fiber-optic or rigid endoscopy and using stroboscopic or high-speed video to infer information about submucosal processes. Previous efforts using optical coherence tomography (OCT) have been limited by small working distances and imaging ranges. Here we report the first full field, high-speed, and long-range OCT images of awake patients’ vocal folds as well as cross-sectional ...

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    10. Functional optical coherence tomography of rat olfactory bulb with periodic odor stimulation

      Functional optical coherence tomography of rat olfactory bulb with periodic odor stimulation

      In rodent olfactory bulb (OB), optical intrinsic signal imaging (OISI) is commonly used to investigate functional maps to odorant stimulations. However, in such studies, the spatial resolution in depth direction (z-axis) is lost because of the integration of light from different depths. To solve this problem, we propose functional optical coherence tomography (fOCT) with periodic stimulation and continuous recording. In fOCT experiments of in vivo rat OB, propionic acid and m-cresol were used as odor stimulus presentations. Such a periodic stimulation enabled us to detect the specific odor-responses from highly scattering brain tissue. Swept source OCT operating at a wavelength ...

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    11. Minimally invasive surgical method to detect sound processing in the cochlear apex by optical coherence tomography

      Minimally invasive surgical method to detect sound processing in the cochlear apex by optical coherence tomography

      Sound processing in the inner ear involves separation of the constituent frequencies along the length of the cochlea. Frequencies relevant to human speech (100 to 500 Hz) are processed in the apex region. Among mammals, the guinea pig cochlear apex processes similar frequencies and is thus relevant for the study of speech processing in the cochlea. However, the requirement for extensive surgery has challenged the optical accessibility of this area to investigate cochlear processing of signals without significant intrusion. A simple method is developed to provide optical access to the guinea pig cochlear apex in two directions with minimal surgery ...

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    12. Doppler optical coherence microscopy and tomography applied to inner ear mechanics

      Doppler optical coherence microscopy and tomography applied to inner ear mechanics

      While it is clear that cochlear traveling waves underlie the extraordinary sensitivity, frequency selectivity, and dynamic range of mammalian hearing, the underlying micromechanical mechanisms remain unresolved. Recent advances in low coherence measurement techniques show promise over traditional laser Doppler vibrometry and video microscopy, which are limited by low reflectivities of cochlear structures and restricted optical access. Doppler optical coherence tomography (DOCT) and Doppler optical coherence microscopy (DOCM) both utilize a broadband source to limit constructive interference of scattered light to a small axial depth called a coherence gate. The coherence gate can be swept axially to image and measure sub-nanometer ...

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    13. Development of a phase-sensitive Fourier domain optical coherence tomography system to measure mouse organ of Corti vibrations in two cochlear turns

      Development of a phase-sensitive Fourier domain optical coherence tomography system to measure mouse organ of Corti vibrations in two cochlear turns

      In this study, we have developed a phase-sensitive Fourier-domain optical coherence tomography system to simultaneously measure the in vivo inner ear vibrations in the hook area and second turn of the mouse cochlea. This technical development will enable measurement of intra-cochlear distortion products at ideal locations such as the distortion product generation site and reflection site. This information is necessary to un-mix the complex mixture of intra-cochlear waves comprising the DPOAE and thus leads to the non-invasive identification of the local region of cochlear damage.

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    14. Intraoperative imaging of pediatric vocal fold lesions using optical coherence tomography

      Intraoperative imaging of pediatric vocal fold lesions using optical coherence tomography

      Optical coherence tomography (OCT) has been previously identified as a promising tool for exploring laryngeal pathologies in adults. Here, we present an OCT handheld probe dedicated to imaging the unique geometry involved in pediatric laryngoscopy. A vertical cavity surface emitting laser-based wavelength-swept OCT system operating at 60 frames per second was coupled to the probe to acquire three-dimensional (3-D) volumes in vivo . In order to evaluate the performance of the proposed probe and system, we imaged pediatric vocal fold lesions of patients going under direct laryngoscopy. Through this in vivo study, we extracted OCT features characterizing each pediatric vocal fold ...

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    15. Automatic airway wall segmentation and thickness measurement for long-range optical coherence tomography images

      Automatic airway wall segmentation and thickness measurement for long-range optical coherence tomography images

      We present an automatic segmentation method for the delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers are accurately extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with sheep airway OCT images. Quantitative thicknesses of the mucosal layers are obtained automatically for smoke inhalation injury experiments.

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    16. Evaluation of confocal laser endomicroscopy as an aid to differentiate primary flat lesions of the larynx: A prospective clinical study

      Evaluation of confocal laser endomicroscopy as an aid to differentiate primary flat lesions of the larynx: A prospective clinical study

      Background In this trial, the ability of confocal laser endomicroscopy (CLE), a new imaging modality with a cellular resolution, to further differentiate primary flat lesions of the larynx was evaluated. Methods First, an optical coherence tomography was used to filter out normal tissue and carcinoma. All other lesions (30 lesions in 19 patients) were investigated with CLE. The suspected diagnosis was compared to histopathology. Results Optical coherence tomography identified all noninvasive lesions. CLE provided further information with cellular resolution. In 2 of 30 cases, low image quality prevented classification. In laryngeal lesions (27 of 30), moderate to high-grade dysplasia was ...

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      Mentions: Herbert Stepp
    17. Imaging of the internal nasal valve using long-range Fourier domain optical coherence tomography

      Imaging of the internal nasal valve using long-range Fourier domain optical coherence tomography

      Objectives/Hypothesis To evaluate for the first time the feasibility and methodology of long-range Fourier domain optical coherence tomography (LR-OCT) imaging of the internal nasal valve (INV) area in healthy individuals. Study Design Prospective individual cohort study. Methods For 16 individuals, OCT was performed in each nare. The angle and the cross-sectional area of the INV were measured. OCT images were compared to corresponding digital pictures recorded with a flexible endoscope. Results INV angle measured by OCT was found to be 18.3° ± 3.1° (mean ± standard deviation). The cross-sectional area was 0.65 ± 0.23 cm 2 . The INV ...

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    18. Using attenuation coefficients from optical coherence tomography as markers of vocal fold maturation

      Using attenuation coefficients from optical coherence tomography as markers of vocal fold maturation

      Objectives/Hypothesis Optical coherence tomography (OCT) is a promising technology to noninvasively assess vocal fold microanatomy. The goal of this study was to develop a methodology using OCT to identify quantifiable markers of vocal fold development. Study Design In vivo study. Methods A two-step process was developed to reproducibly image the midmembranous vocal fold edge of 10 patients younger than 2 years and 10 patients between 11 and 16 years of age using OCT. An image analysis algorithm was implemented to extract OCT-derived A-lines for each patient. These A-lines were divided into three zones according to apparent changes in slope ...

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    19. Multimodal imaging using optical coherence tomography and endolaryngeal ultrasonography in a new rabbit VX2 laryngeal cancer model

      Multimodal imaging using optical coherence tomography and endolaryngeal ultrasonography in a new rabbit VX2 laryngeal cancer model

      Background and Objective Optical coherence tomography (OCT) provides ultrahigh-resolution imaging of tissues within a depth of a few millimeters, whereas ultrasonography provides good imaging further below the surface. We aimed to develop a minimally invasive rabbit model of VX2 laryngeal cancer, suitable for these two imaging modalities through a transoral approach. We also sought to study the utility of combined OCT and endolaryngeal ultrasonography (EUS) for evaluation of early and advanced laryngeal cancer, using this model. Materials and Methods VX2 tumor suspension was inoculated into the vocal folds of ten rabbits by injection through the trans-thyrohyoid membrane. The tumor model ...

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    20. Oregon Health and Science University Receives NIH Grant for Studying In Vivo Organ of Corti Mechanoelectric Physiology

      Oregon Health and Science University Receives  NIH Grant for Studying In Vivo Organ of Corti Mechanoelectric Physiology

      Oregon Health and Science University Receives a 2015 NIH Grant for $370,365 for Studying In Vivo Organ of Corti Mechanoelectric Physiology. The principal investigator is Alfred Nuttall. THe program began in 1979 and ends in 2016. Below is a summary of the proposed work. A goal of the cochlear physiology laboratory is to understand how the components of the organ of Corti enhance the sound induced vibration of the basilar membrane, a process known as cochlear amplification (CA). Two questions of broad interest are to be studied; how do the outer hair cells transmit force to activate the CA ...

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    21. Lymphatic response to depilation-induced inflammation in mouse ear assessed with label-free optical lymphangiography

      Lymphatic response to depilation-induced inflammation in mouse ear assessed with label-free optical lymphangiography

      Background and Objectives Optical microangiography (OMAG) is a noninvasive technique capable of imaging 3D microvasculature. OMAG-based optical lymphangiography has been developed for 3D visualization of lymphatic vessels without the need for exogenous contrast agents. In this study, we utilize the optical lymphangiography to investigate dynamic changes in lymphatic response within skin tissue to depilation-induced inflammation by using mouse ear as a simple tissue model. Materials and Methods A spectral-domain optical coherence tomography (OCT) system is used in this study to acquire volumetric images of mouse ear. The system operates under the ultrahigh-sensitive OMAG scanning protocol with five repetitions for each ...

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    22. Imaging the tympanic membrane oscillation ex vivo with Doppler optical coherence tomography during simulated Eustachian catarrh

      Imaging the tympanic membrane oscillation ex vivo with Doppler optical coherence tomography during simulated Eustachian catarrh

      Recently, optical coherence tomography (OCT) was utilized in multiple studies for structural and functional imaging of the middle ear and the tympanic membrane. Since Doppler OCT allows both, the spatially resolved measurement of the tympanic membrane oscillation and high-resolution imaging, it is regarded as a promising tool for future in vivo applications. In this study, Doppler OCT is utilized for the visualization of the tympanic membrane oscillation in temporal bones with simulated Eustachian catarrh, which was realized by generating a depression in the tympanic cavity. The transfer function, meaning the oscillation amplitude normalized to the applied sound pressure, is measured ...

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    23. Miniature, minimally invasive, tunable endoscope for investigation of the middle ear

      Miniature, minimally invasive, tunable endoscope for investigation of the middle ear

      We demonstrate a miniature, tunable, minimally invasive endoscope for diagnosis of the auditory system. The probe is designed to sharply image anatomical details of the middle ear without the need for physically adjusting the position of the distal end of the endoscope. This is achieved through the addition of an electrowetted, tunable, electronically-controlled lens to the optical train. Morphological imaging is enabled by scanning light emanating from an optical coherence tomography system. System performance was demonstrated by imaging part of the ossicular chain and wall of the middle ear cavity of a normal mouse. During the experiment, we electronically moved ...

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    24. Optical coherence tomography system requirements for clinical diagnostic middle ear imaging

      Optical coherence tomography system requirements for clinical diagnostic middle ear imaging

      Noninvasive middle ear imaging using optical coherence tomography (OCT) presents some unique challenges for real-time, clinical use in humans. We present results from a two-dimensional/three-dimensional OCT system built to assess the imaging requirements of clinical middle ear imaging, and the technical challenges associated with them. These include the need to work at a low numerical aperture, the deleterious effects of transtympanic imaging on image quality at the ossicles, sensitivity requirements for clinical fidelity of images at real-time rates, and the high dynamic-range requirements of the ear. We validated the system by imaging cadaveric specimens with simulated disorders to show ...

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    1-24 of 231 1 2 3 4 5 6 7 8 9 10 »
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