1. Articles in category: Otolaryngology

    1-24 of 242 1 2 3 4 5 6 7 8 9 10 »
    1. Minimal basilar membrane motion in low-frequency hearing

      Minimal basilar membrane motion in low-frequency hearing

      To perceive speech, the brain relies on inputs from sensory cells located near the top of the spiral-shaped cochlea. This low-frequency region of the inner ear is anatomically difficult to access, and it has not previously been possible to study its mechanical response to sound in intact preparations. Here, we used optical coherence tomography to image sound-evoked vibration inside the intact cochlea. We show that low-frequency sound moves a small portion of the basilar membrane, and that the motion declines in an exponential manner across the basilar membrane. Hence, the response of the hearing organ to speech-frequency sounds is different ...

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    2. New discovery on how the inner ear works

      New discovery on how the inner ear works

      Researchers have found that the parts of the inner ear that process sounds such as speech and music seem to work differently than other parts of the inner ear. Researchers from Linköping University are part of the team behind the discovery. "This helps us understand the mechanisms that enable us to perceive speech and music. We hope that more knowledge about the capabilities of the ear will lead to better treatments for the hearing impaired," says Anders Fridberger, professor of neuroscience at Linköping University. To perceive speech and music, you must be able to hear low-frequency sound. And ...

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    3. Swept Source Optical Coherence Tomography Imaging of the Middle Ear Cavity (Thesis)

      Swept Source Optical Coherence Tomography Imaging of the Middle Ear Cavity (Thesis)

      Otitis media (OM), a bacterial infection of the middle ear, is a common pediatric disease. Chronic and recurrent OM is often treated with the surgical placement of tympanostomy tubes in the tympanic membrane (TM), which is the most common reason for pediatric surgery and anesthesia. Antibiotic treatment for chronic OM (COM) is often ineffective, which is explained by the hypothesis that OM is a biofilm-related disease. Recent studies in humans and animals have accumulated evidence for biofilm growth on the middle ear mucosa in COM. However, these studies have required invasive methods to obtain middle ear mucosa samples. Optical Coherence ...

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    4. Collagen Content Limits Optical Coherence Tomography Image Depth in Porcine Vocal Fold Tissue

      Collagen Content Limits Optical Coherence Tomography Image Depth in Porcine Vocal Fold Tissue

      Objective Vocal fold scarring, a condition defined by increased collagen content, is challenging to treat without a method of noninvasively assessing vocal fold structure in vivo. The goal of this study was to observe the effects of vocal fold collagen content on optical coherence tomography imaging to develop a quantifiable marker of disease. Study Design Excised specimen study. Setting Massachusetts Eye and Ear Infirmary. Subjects and Methods Porcine vocal folds were injected with collagenase to remove collagen from the lamina propria. Optical coherence tomography imaging was performed preinjection and at 0, 45, 90, and 180 minutes postinjection. Mean pixel intensity ...

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    5. Quantitative Evaluation of Adult Subglottic Stenosis Using Intraoperative Long-range Optical Coherence Tomography

      Quantitative Evaluation of Adult Subglottic Stenosis Using Intraoperative Long-range Optical Coherence Tomography

      Objectives: To determine the feasibility of long-range optical coherence tomography (LR-OCT) as a tool to intraoperatively image and measure the subglottis and trachea during suspension microlaryngoscopy before and after endoscopic treatment of subglottic stenosis (SGS). Methods: Long-range optical coherence tomography of the adult subglottis and trachea was performed during suspension microlaryngoscopy before and after endoscopic treatment for SGS. The anteroposterior and transverse diameters, cross-sectional area (CSA), distance from the vocal cords, and length of the SGS were measured using a MATLAB software. Pre-intervention and postintervention airway dimensions were compared. Three-dimensional volumetric airway reconstructions were generated using medical image processing software ...

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    6. Optical Coherence Tomography to Measure Sound-Induced Motions Within the Mouse Organ of Corti In Vivo

      Optical Coherence Tomography to Measure Sound-Induced Motions Within the Mouse Organ of Corti In Vivo

      The measurement of mechanical vibrations within the living cochlea is critical to understanding the first nonlinear steps in auditory processing, hair cell stimulation, and cochlear amplification. However, it has proven to be a challenging endeavor. This chapter describes how optical coherence tomography (OCT) can be used to measure vibrations within the tissues of the organ of Corti. These experimental measurements can be performed within the unopened cochlea of living mice routinely and reliably.

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    7. Postdoctoral research position for Biomedical/Optics Engineer Scientist at Harvard Medical School and Wellman Center

      Postdoctoral research position for Biomedical/Optics Engineer Scientist at Harvard Medical School and Wellman Center

      The ear is a remarkable example of a biomechanical system. The goal of the OtoBiomechanics Group in the Otolaryngology Department at the Harvard Medical School is to use the OCT imaging modality combined with computational models and physiological measurements to understand the high sensitivity, high frequency selectivity and wide bandwidth of mammalian hearing. The project is well funded by grants from the NIH. Applications are invited for a post-doctoral research fellowship position to develop and build a state-of-the-art micro optical coherence topography (u-OCT) system to study cochlear and middle ear imaging and vibrometry in the laboratories of Profs. Sunil Puria ...

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    8. The diagnosis of nasopharyngeal carcinoma by optical coherence tomography (OCT)

      The diagnosis of nasopharyngeal carcinoma by optical coherence tomography (OCT)

      We have attempted to explore the intrinsic differences in the optical properties of the nasopharyngeal carcinoma (NPC) and normal tissue by optical coherence tomography (OCT). OCT imaging of normal tissue provided three layers of epithelium, lamina propria, and the brighter interface of basement membrane; while carcinomas disrupted the layered construction embedded in signal-poor images. The morphologies were consistent with histological findings. Sensitivity and specificity were 90% and 100%, respectively. This pilot study demonstrates that NPC could be diagnosed by visualization, which implies that OCT might be potentially used to differentiate normal from NPC tissue in the early stage as an ...

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    9. Optical sensing system for cochlear implant surgery

      Optical sensing system for cochlear implant surgery

      A sensing system for implant surgery includes an insertion device for moving an implant into a narrow cavity in a patient's body. A sensor measures the distance from an end of the insertion device to anatomic surfaces at a distance from the end of the insertion device. An optical coherence tomography (OCT) system integrates the sensor and produces OCT images, which can be quantified to distance measurements. The system is particularly useful for cochlear implant surgery.

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    10. Attenuation Coefficients, Pixel Intensity, and Texture Analysis as Quantitative Parameters for Analyzing Optical Coherence Tomography Images of Vocal Fold Tissue (Thesis)

      Attenuation Coefficients, Pixel Intensity, and Texture Analysis as Quantitative Parameters for Analyzing Optical Coherence Tomography Images of Vocal Fold Tissue (Thesis)

      Optical coherence tomography is a promising technology to noninvasively assess vocal fold microanatomy. However, many studies using optical coherence tomography to evaluate vocal fold tissue are largely qualitative in nature and lack quantitative measures that might be useful in clinical decision-making. The goal of this thesis was to identify quantitative metrics that can be extracted from optical coherence tomography vocal fold imaging and applied to the surgical subspecialty of Laryngology. The first goal of this study was to determine if optical coherence tomography was sensitive enough to distinguish subtle differences between vocal folds based on vocal fold content using attenuation ...

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    11. Oregon Health and Science University Receives NIH Grant for Ossicle Vibration Measurement sin Conductive Hearing Loss

      Oregon Health and Science University Receives NIH Grant for Ossicle Vibration Measurement sin Conductive Hearing Loss

      Oregon Health and Science University Receives a 2016 NIH Grant for $418,717 for Ossicle Vibration Measurement sin Conductive Hearing Loss. The principal investigator is Steven Jaques. The program began in 2013 and ends in 2017. Below is a summary of the proposed work. The proposal develops a hand-held otoscope that uses optical coherence tomography (OCT) to image the tympanic membrane and ossicles behind an intact tympanic membrane. The system is based on spectral Fourier-domain OCT and can measure vibrations of the ossicles (malleus, incus, stapes) of the middle ear on the scale of nm to ¿m amplitude. In Aim ...

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    12. 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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    13. 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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    14. 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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    15. 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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    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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