1. Articles in category: Otolaryngology

    1-24 of 259 1 2 3 4 ... 9 10 11 »
    1. In vivo 3D imaging of the human tympanic membrane using a wide-field diagonal-scanning optical coherence tomography probe

      In vivo 3D imaging of the human tympanic membrane using a wide-field diagonal-scanning optical coherence tomography probe

      A wide-field optical coherence tomography (OCT) probe was developed that adapts a diagonal-scanning scheme for three-dimensional (3D) in vivo imaging of the human tympanic membrane. The probe consists of a relay lens to enhance the lateral scanning range up to 7 mm. Motion artifacts that occur with the use of handheld probes were found to be decreased owing to the diagonal-scanning pattern, which crosses the center of the sample to facilitate entire 3D scans. 3D images could be constructed from a small number of two-dimensional OCT images acquired using the diagonal-scanning technique. To demonstrate the usefulness and performance of the ...

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    2. Seeing, understanding how we hear

      Seeing, understanding how we hear

      Cutting-edge technology is giving QEII Health Sciences Centre clinicians a close up look at the inner workings of the human ear. “We are the only place in the world that has managed to measure ear vibrations in humans. We are definitely the furthest ahead,” says Dr. Manohar Bance, QEII ear surgeon. When it comes to middle ear dysfunctions, surgeries to cut open the tympanic membrane, or eardrum, are frequently conducted on patients in attempt to identify problems and restore vibrating connections. Anything that can block the passage of vibrations will lead to hearing loss. Fluid is one thing, which is ...

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    3. Intraoperative assessment of laryngeal pathologies with optical coherence tomography integrated into a surgical microscope

      Intraoperative assessment of laryngeal pathologies with optical coherence tomography integrated into a surgical microscope

      Objective Endoscopic examination followed by tissue biopsy is the gold standard in the evaluation of lesions of the upper aerodigestive tract. However, it can be difficult to distinguish between healthy mucosa, dysplasia, and invasive carcinoma. Optical coherence tomography (OCT) is a non-invasive technique which acquires high-resolution, cross-sectional images of tissue in vivo . Integrated into a surgical microscope, it allows the intraoperative evaluation of lesions simultaneously with microscopic visualization. Study Design In a prospective case series, we evaluated the use of OCT integrated into a surgical microscope during microlaryngoscopy to help differentiating various laryngeal pathologies. Methods 33 patients with laryngeal pathologies ...

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    4. Extratympanic imaging of middle and inner ear structures of mouse and rat using optical coherence tomography

      Extratympanic imaging of middle and inner ear structures of mouse and rat using optical coherence tomography

      ackground and Objective: Noninvasive middle and inner ear imaging using optical coherence tomography (OCT) presents some unique challenges for real-time, clinical use in animals and humans. The goal of this study was to investigate whether OCT provides information about the middle and inner ear microstructures by examining extratympanic structures. Materials and Methods: Five mice and rats were included in the experiment, and the swept-source OCT system was tested to identify the middle and inner ear microstructures and to measure the length or thickness of various structures. Results: It was possible to see middle ear structures through the tympanic membrane with ...

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    5. Signal competition in optical coherence tomography and its relevance for cochlear vibrometry

      Signal competition in optical coherence tomography and its relevance for cochlear vibrometry

      The usual technique for measuring vibration within the cochlear partition is heterodyne interferometry. Recently, spectral domain phase microscopy (SDPM) was introduced and offers improvements over standard heterodyneinterferometry. In particular, it has a penetration depth of several mm due to working in the infrared range, has narrow and steep optical sectioning due to using a wideband light source, and is able to measure from several cochlear layers simultaneously. However, SDPM is susceptible to systematic error due to “phase leakage,” in which the signal from one layer competes with the signal from other layers. Here, phase leakage is explored in vibration measurements ...

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      Mentions: Christine Hendon
    6. Low-cost hand-held probe for depth-resolved low-coherence interferometry

      Low-cost hand-held probe for depth-resolved low-coherence interferometry

      We report on the development of a low-cost hand-held low-coherence interferometric imaging system based on the principle of linear optical coherence tomography (Linear OCT), a technique which was first proposed in the early 2000s as a simpler alternative to the conventional time-domain and Fourier-domain OCT. A bench-top implementation of the proposed technique is first presented and validated. The axial resolution, SNR, and sensitivity roll-of of the system was estimated to be 5.2 μm and 80 dB, and 3.7 dB over a depth of 0.15 mm, respectively. After validating the bench-top system, two hand-held probe implementations for contact-based ...

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    7. Experimental Visualization of Labyrinthine Structure with Optical Coherence Tomography

      Experimental Visualization of Labyrinthine Structure with Optical Coherence Tomography

      Introduction: Visualization of inner ear structures is a valuable strategy for researchers and clinicians working on hearing pathologies. Optical coherence tomography (OCT) is a high-resolution imaging technology which may be used for the visualization of tissues. In this experimental study we aimed to evaluate inner ear anatomy in well-prepared human labyrinthine bones. Materials and Methods: Three fresh human explanted temporal bones were trimmed, chemically decalcified with ethylenediaminetetraacetic acid (EDTA), and mechanically drilled under visual control using OCT in order to reveal the remaining bone shell. After confirming decalcification with a computed tomography (CT) scan, the samples were scanned with OCT ...

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    8. Mesenchymal stem cell-laden hybrid scaffold for regenerating subacute tympanic membrane perforation

      Mesenchymal stem cell-laden hybrid scaffold for regenerating subacute tympanic membrane perforation

      ympanic membrane (TM) perforation is one of the most common otology complications. To date, there has not been reported TM regeneration using bioprinted scaffold. The purpose of this study was to evaluate the efficacy and feasibility of bioprinted polycaprolactone/collagen/alginate-mesenchymal stem cell (PCAMSC) scaffolds for the regeneration of subacute TM perforation. Sprague-Dawley rats were used in an animal model of subacute TM perforation. In the experimental group (n = 7), bioprinted 3D PCAMSC scaffold was placed on the perforation. The control group (n = 7) were treated with polycaprolactone/collagen/alginate (PCA) scaffold. Healing time, acoustic-mechanical properties, and morphological analysis were ...

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      Mentions: Byeong Ha Lee
    9. Dynamic nanomechanical analysis of the vocal fold structure in excised larynges

      Dynamic nanomechanical analysis of the vocal fold structure in excised larynges

      Objectives/Hypothesis Quantification of clinical outcomes after vocal fold (VF) interventions is challenging with current technology. High-speed digital imaging and optical coherence tomography (OCT) of excised larynges assess intact laryngeal function, but do not provide critical biomechanical information. We developed a protocol to quantify tissue properties in intact, excised VFs using dynamic nanomechanical analysis (nano-DMA) to obtain precise biomechanical properties in the micrometer scale. Study Design Experimental animal study. Methods Three pig larynges were bisected in the sagittal plane, maintaining an intact anterior commissure, and subjected to nano-DMA at nine locations with a 250-μm flat-tip punch and frequency sweep ...

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    10. Human ex-vivo oral tissue imaging using spectral domain polarization sensitive optical coherence tomography

      Human ex-vivo oral tissue imaging using spectral domain polarization sensitive optical coherence tomography

      We report the use of spectral domain polarization sensitive optical coherence tomography for ex-vivo imaging of human oral mandibular tissue samples. Our results show that compared to the changes observed in the epithelium thickness and the decay constant of A-scan intensity profile, a much larger degree of change was observed in the phase retardation for tissue sites progressing from normal to the malignant state. These results suggest that monitoring of tissue retardance can help in better differentiation of normal and cancerous oral tissue sites.

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    11. Doppler optical coherence tomography as a promising tool for detecting fluid in the human middle ear

      Doppler optical coherence tomography as a promising tool for detecting fluid in the human middle ear

      The treatment of otitis media requires classifying the effusion in the tympanic cavity for choosing appropriate therapeutic strategies. Otoscopic examination of the middle ear depends on the expertise of the physician and is often hampered in case of inflammatory alterations of the tympanic membrane. In otologic research, optical coherence tomography is an innovative non-invasive imaging technique utilized for visualizing the tympanic membrane. This ex vivo study presents the possibility of OCT and Doppler-OCT for the detection of effusions in the tympanic cavity. Structural OCT imaging allows the direct visualization of scattering fluids behind the tympanic membrane. In addition, the measurement ...

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    12. Long-range, wide-field swept-source optical coherence tomography with GPU accelerated digital lock-in Doppler vibrography for real-time, in vivo middle ear diagnostics

      Long-range, wide-field swept-source optical coherence tomography with GPU accelerated digital lock-in Doppler vibrography for real-time, in vivo middle ear diagnostics

      We present the design, implementation and validation of a swept-source optical coherence tomography (OCT) system for real-time imaging of the human middle ear in live patients. Our system consists of a highly phase-stable Vernier-tuned distributed Bragg-reflector laser along with a real-time processing engine implemented on a graphics processing unit. We use the system to demonstrate, for the first time in live subjects, real-time Doppler measurements of middle ear vibration in response to sound, video rate 2D B-mode imaging of the middle ear and 3D volumetric B-mode imaging. All measurements were performed non-invasively through the intact tympanic membrane demonstrating that the ...

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    13. Micro-optical coherence tomography of the mammalian cochlea

      Micro-optical coherence tomography of the mammalian cochlea

      The mammalian cochlea has historically resisted attempts at high-resolution, non-invasive imaging due to its small size, complex three-dimensional structure, and embedded location within the temporal bone. As a result, little is known about the relationship between an individual’s cochlear pathology and hearing function, and otologists must rely on physiological testing and imaging methods that offer limited resolution to obtain information about the inner ear prior to performing surgery. Micro-optical coherence tomography (μOCT) is a non-invasive, low-coherence interferometric imaging technique capable of resolving cellular-level anatomic structures. To determine whether μOCT is capable of resolving mammalian intracochlear anatomy, fixed guinea pig ...

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    14. A Mosaicking Approach for In Vivo Thickness Mapping of the Human Tympanic Membrane Using Low Coherence Interferometry

      A Mosaicking Approach for In Vivo Thickness Mapping of the Human Tympanic Membrane Using Low Coherence Interferometry

      The thickness of the human tympanic membrane (TM) is known to vary considerably across different regions of the TM. Quantitative determination of the thickness distribution and mapping of the TM is of significant importance in hearing research, particularly in mathematical modeling of middle-ear dynamics. Change in TM thickness is also associated with several middle-ear pathologies. Determination of the TM thickness distribution could therefore also enable a more comprehensive diagnosis of various otologic diseases. Despite its importance, very limited data on human TM thickness distribution, obtained almost exclusively from ex vivo samples, are available in the literature. In this study, the ...

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    15. Biomedical Optics in Otorhinolaryngology (Textbook)

      Biomedical Optics in Otorhinolaryngology (Textbook)

      Biomedical Optics in Otorhinolaryngology: Head and Neck Surgery gives an overview of current technology in biomedical optics relevant to the field of Otorhinolaryngology and head and neck surgery. It provides a comprehensive source of knowledge for researchers and active clinicians seeking information on the principles and practical use of novel diagnostic and therapeutic technology. While most books focus exclusively on laser surgery, which has been largely unchanged for the past 15 years, optical diagnostics and head and neck PDT (photodynamic therapy) are usually entirely overlooked. This book contains a basic introduction into the physics of light and its propagation, lasers ...

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    16. Diagnosis of subglottic stenosis in a rabbit model using long-range optical coherence tomography

      Diagnosis of subglottic stenosis in a rabbit model using long-range optical coherence tomography

      Objectives/Hypothesis Current imaging modalities lack the necessary resolution to diagnose subglottic stenosis. The aim of this study was to use optical coherence tomography (OCT) to evaluate nascent subglottic mucosal injury and characterize mucosal thickness and structural changes using texture analysis in a simulated intubation rabbit model. Study Design Prospective animal study in rabbits. Methods Three-centimeter-long sections of endotracheal tubes (ETT) were endoscopically placed in the subglottis and proximal trachea of New Zealand White rabbits (n = 10) and secured via suture. OCT imaging and conventional endoscopic video was performed just prior to ETT segment placement (day 0), immediately after tube ...

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    17. OPTICAL COHERENCE TOMOGRAPHY IN THE LARYNGEAL ARYTENOID MUCOSA FOR DOCUMENTATION OF PHARMACOLOGICAL TREATMENTS AND GENETIC ASPECTS: A PROTOCOL

      OPTICAL COHERENCE TOMOGRAPHY IN THE LARYNGEAL ARYTENOID MUCOSA FOR DOCUMENTATION OF PHARMACOLOGICAL TREATMENTS AND GENETIC ASPECTS: A PROTOCOL

      Background : Optical coherence tomography (OCT) is an imaging technology that provides cross-sectional images of subsurface tissue structures in the larynx without biopsy. Focus has until now been on the vocal folds. Since many kinds of mucosal disorders can be defined in the arytenoid regions behind the vocal folds, and not on the vocal folds, we focus on this area in this protocol. Objective : A superficial oedema, grading 1–5 of the arytenoid regions, can be made with high-speed films of 4,000 pictures/sec. A supplementary larynx set up with a clinical probe for OCT with cross-sectional measures can be ...

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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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    1-24 of 259 1 2 3 4 ... 9 10 11 »
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