1. Articles from Steven L. Jacques

    1-24 of 32 1 2 »
    1. Semi-automated registration and segmentation for gingival tissue volume measurement on 3D OCT images

      Semi-automated registration and segmentation for gingival tissue volume measurement on 3D OCT images

      The change in gingival tissue volume may be used to indicate changes in gingival inflammation, which may be useful for the clinical assessment of gingival health. Properly quantifying gingival tissue volume requires a robust technique for accurate registration and segmentation of longitudinally captured 3-dimensional (3D) images. In this paper, a semi-automated registration and segmentation method for micrometer resolution measurement of gingival-tissue volume is proposed for 3D optical coherence tomography (OCT) imaging. For quantification, relative changes in gingiva tissue volume are measured based on changes in the gingiva surface height using the tooth surface as a reference. This report conducted repeatability ...

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    2. Microscale light management and inherent optical properties of intact corals studied with optical coherence tomography

      Microscale light management and inherent optical properties of intact corals studied with optical coherence tomography

      Coral reefs are highly productive photosynthetic systems and coral optics studies suggest that such high efficiency is due to optimised light scattering by coral tissue and skeleton. Here, we characterise the inherent optical properties, i.e., the scattering coefficient, μ s , and the anisotropy of scattering, g , of 8 intact coral species using optical coherence tomography (OCT). Specifically, we describe light scattering by coral skeletons, coenoarc tissues, polyp tentacles and areas covered by fluorescent pigments (FP). Our results reveal that light scattering between coral species ranges from μ s = 3 mm -1 ( Stylophora pistillata ) to μ s = 25 mm -1 ( Echinopora lamelosa ). For ...

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    3. Feature Of The Week 03/05/2017: In Vivo Imaging of Coral Tissue and Skeleton with Optical Coherence Tomography

      Feature Of The Week 03/05/2017: In Vivo Imaging of Coral Tissue and Skeleton with Optical Coherence Tomography

      Optical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissues in vivo and in real time. We present the first application of OCT for in vivo imaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host ...

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    4. In vivo imaging of coral tissue and skeleton with optical coherence tomography

      In vivo imaging of coral tissue and skeleton with optical coherence tomography

      Application of optical coherence tomography (OCT) for in vivo imaging of tissue and skeleton structure of intact living corals enabled the non-invasive visualization of coral tissue layers (endoderm versus ectoderm), skeletal cavities and special structures such as mesenterial filaments and mucus release from intact living corals. Coral host chromatophores containing green fluorescent protein-like pigment granules appeared hyper-reflective to near-infrared radiation allowing for excellent optical contrast in OCT and a rapid characterization of chromatophore size, distribution and abundance. In vivo tissue plasticity could be quantified by the linear contraction velocity of coral tissues upon illumination resulting in dynamic changes in the ...

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    5. In vivo imaging of coral tissue and skeleton with optical coherence tomography

      In vivo imaging of coral tissue and skeleton with optical coherence tomography

      Optical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissues in vivo and in real time. We present the first application of OCT for in vivo imaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host ...

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    6. 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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    7. 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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    8. Methods of Melanoma Detection

      Methods of Melanoma Detection

      Detection and removal of melanoma, before it has metastasized, dramatically improves prognosis and survival. The purpose of this chapter is to (1) summarize current methods of melanoma detection and (2) review state-of-the-art detection methods and technologies that have the potential to reduce melanoma mortality. Current strategies for the detection of melanoma range from population-based educational campaigns and screening to the use of algorithm-driven imaging technologies and performance of assays that identify markers of transformation. This chapter will begin by describing state-of-the-art methods for educating and increasing awareness of at-risk individuals and for performing comprehensive screening examinations. Standard and advanced photographic ...

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    9. Two dimensional vibrations of the guinea pig apex organ of Corti measured in vivo using phase sensitive Fourier domain optical coherence tomography

      Two dimensional vibrations of the guinea pig apex organ of Corti measured in vivo using phase sensitive Fourier domain optical coherence tomography

      In this study, we measure the in vivo apical-turn vibrations of the guinea pig organ of Corti in both axial and radial directions using phase-sensitive Fourier domain optical coherence tomography. The apical turn in guinea pig cochlea has best frequencies around 100 – 500 Hz which are relevant for human speech. Prior measurements of vibrations in the guinea pig apex involved opening the otic capsule, which has been questioned on the basis of the resulting changes to cochlear hydrodynamics. Here this limitation is overcome by measuring the vibrations through bone without opening the otic capsule. Furthermore, we have significantly reduced the ...

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    10. Feature Of The Week 3/17/13: Using Optical Coherence Tomography to Study Mechanisms of Hearing

      Feature Of The Week 3/17/13: Using Optical Coherence Tomography to Study Mechanisms of Hearing

      The Oregon Hearing Research Centre (OHRC) at the Oregon Health and Science University (OHSU), Portland, Oregon is one of the strongest hearing research groups in the world, and one of the early adopters of optical coherence tomography technology in the field of hearing research. Researchers at OHRC have developed a couple of novel OCT based imaging technologies for functional imaging of middle and inner ear. This includes high-speed OCT system for in vivo imaging of microstructural morphology and micvascular perfusion within the cochlea [1,2], phase-sensitive time-domain and Fourier domain OCT for studying cochlear micromechanics [3,4] and middle ear ...

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    11. Measurement of in vivo basal-turn vibrations of the organ of Corti using phase-sensitive Fourier domain optical coherence tomography

      Measurement of in vivo basal-turn vibrations of the organ of Corti using phase-sensitive Fourier domain optical coherence tomography

      A major reason we can perceive faint sounds and communicate in noisy environments is that the outer hair cells of the organ of Corti enhance the sound-evoked motions inside the cochlea. To understand how the organ of Corti works, we have built and tested the phase-sensitive Fourier domain optical coherence tomography (PSFDOCT) system. This system has key advantages over our previous time domain OCT system [1]. The PSFDOCT system has better signal to noise and simultaneously acquires vibration data from all points along the optical-axis [2]. Feasibility of this system to measure in vitro cochlear vibrations in the apex was ...

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    12. Depth-resolved dual-beamlet vibrometry based on Fourier domain low coherence interferometry

      Depth-resolved dual-beamlet vibrometry based on Fourier domain low coherence interferometry

      We present an optical vibrometer based on delay-encoded, dual-beamlet phase-sensitive Fourier domain interferometric system to provide depth-resolved subnanometer scale vibration information from scattering biological specimens. System characterization, calibration, and preliminary vibrometry with biological specimens were performed. The proposed system has the potential to provide both amplitude and direction of vibration of tissue microstructures on a single two-dimensional plane.

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    13. Feature Of The Week 07/01/12: Enhanced Optical Clearing of Skin In Vivo and OCT In-Depth Imaging

      Feature Of The Week 07/01/12: Enhanced Optical Clearing of Skin In Vivo and OCT In-Depth Imaging

      Imaging methods such as optical coherence tomography (OCT), confocal reflectance/ fluorescence microscopy, second-harmonic generation microscopy, and 2-photon microscopy are limited by the optical scattering properties of the skin to superficial depths. Optical clearing technique using high refractive index and hyperosmolarity agents can reduce the scattering of biological tissues. With this approach, better optical imaging depth and contrast have been presented and deeper optical treatment has been achieved. However, noninvasive optical clearing of skin in vivo is difficult, because the outermost layer of the skin, the stratum corneum, presents a significant barrier to topically applied OCAs. In this work, OCT imaging ...

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    14. Enhanced optical clearing of skin in vivo and optical coherence tomography in-depth imaging

      Enhanced optical clearing of skin in vivo and optical coherence tomography in-depth imaging

      The strong optical scattering of skin tissue makes it very difficult for optical coherence tomography (OCT) to achieve deep imaging in skin. Significant optical clearing of in vivo rat skin sites was achieved within 15 min by topical application of an optical clearing agent PEG-400, a chemical enhancer (thiazone or propanediol), and physical massage. Only when all three components were applied together could a 15 min treatment achieve a three fold increase in the OCT reflectance from a 300 μm depth and 31% enhancement in image depth Zthreshold.

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    15. Feasibility of spectral-domain phase-sensitive optical coherence tomography for middle ear vibrometry

      Feasibility of spectral-domain phase-sensitive optical coherence tomography for middle ear vibrometry

      We describe a novel application of spectral-domain phase-sensitive optical coherence tomography (SD PS-OCT) to detect the tiny motions of the middle ear structures, such as the tympanic membrane and ossicular chain, and their morphological features for differential diagnosis of CHL. This technique has the potential to provide meaningful vibration of ossicles with a vibration sensitivity of ∼ 0.5  nm at 1 kHz of acoustic stimulation. To the best of our knowledge, this is the first demonstration of depth-resolved vibration imaging of ossicles with a PS-OCT system at a nanometer scale.

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    16. Feature Of The Week 5/27/11: Researchers Utilize Optical Coherence Tomography to Perform in vivo Investigation into the Process of Hearing

      Feature Of The Week 5/27/11: Researchers Utilize Optical Coherence Tomography to Perform in vivo Investigation into the Process of Hearing

      A multidisciplinary research groups spanning several countries (USA, China, Sweden) are using optical coherence tomography (OCT) to investigate minute changes in hair cells within the cochlea - the auditory portion of the inner ear. Below is a summary of their work. Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating ...

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    17. In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea

      In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea

      Background Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating force. These length changes, which have not previously been measured in vivo, must be correctly timed with the acoustic stimulus to produce amplification. Methodology/Principal Findings Using in vivo optical coherence tomography, we demonstrate that outer hair cells in ...

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    18. Simultaneous depth-resolved imaging of sub-nanometer scale ossicular vibrations and morphological features of the human-cadaver middle ear with spectral-domain phase-sensitive optical coherence tomography

      Simultaneous depth-resolved imaging of sub-nanometer scale ossicular vibrations and morphological features of the human-cadaver middle ear with spectral-domain phase-sensitive optical coherence tomography

      We describe a novel method for the detection of the tiny motions of the middle ear (ME) ossicles and their morphological features with a spectral-domain phase sensitive optical coherence tomography (PS-OCT). Laser Doppler Vibrometry (LDV) and its variations are the most extensively used methods for studding the vibrational modes of the ME. However, most techniques are limited to single point analysis methods, and do not have the ability to provide depth resolved simultaneous imaging of multiple points on the ossicles especially with the intact eardrum. Consequently, the methods have the limited ability to provide relative vibration information at these points ...

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    19. Absolute measurement of subnanometer scale vibration of cochlear partition of an excised guinea pig cochlea using spectral-domain phase-sensitive optical coherence tomography

      Absolute measurement of subnanometer scale vibration of cochlear partition of an excised guinea pig cochlea using spectral-domain phase-sensitive optical coherence tomography

      Direct measurement of absolute vibration parameters from different locations within the mammalian organ of Corti is crucial for understanding the hearing mechanics such as how sound propagates through the cochlea and how sound stimulates the vibration of various structures of the cochlea, namely, basilar membrane (BM), recticular lamina, outer hair cells and tectorial membrane (TM). In this study we demonstrate the feasibility a modified phase-sensitive spectral domain optical coherence tomography system to provide subnanometer scale vibration information from multiple angles within the imaging beam. The system has the potential to provide depth resolved absolute vibration measurement of tissue microstructures from ...

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    20. Imaging Organ of Corti Vibration Using Fourier-Domain OCT

      Imaging Organ of Corti Vibration Using Fourier-Domain OCT

      Measuring the sound stimulated vibration from various structures in the organ of Corti is important in understanding how the small vibrations are amplified and detected. In this study we examine the feasibility of using phase-sensitive Fourier domain optical coherence tomography (PSFD-OCT) to measure vibration of the cellular structures of the organ of Corti. PSFD-OCT is a low coherence interferrometry system where the interferrogram is detected as a function of wavelength. The phase of the Fourier transformation of the detected spectra contains path deference (between the sample arm and the reference arm) information of the interferometer. In PSFD-OCT this phase is ...

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    21. A differentially amplified motion in the ear for near-threshold sound detection

      A differentially amplified motion in the ear for near-threshold sound detection

      The ear is a remarkably sensitive pressure fluctuation detector. In guinea pigs, behavioral measurements indicate a minimum detectable sound pressure of ~20 μPa at 16 kHz. Such faint sounds produce 0.1-nm basilar membrane displacements, a distance smaller than conformational transitions in ion channels. It seems that noise within the auditory system would swamp such tiny motions, making weak sounds imperceptible. Here we propose a new mechanism contributing to a resolution of this problem and validate it through direct measurement. We hypothesized that vibration at the apical side of hair cells is enhanced compared with that at the commonly measured ...

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    22. Dermal reflectivity determined by optical coherence tomography is an indicator of epidermal hyperplasia and dermal edema within inflamed skin

      Dermal reflectivity determined by optical coherence tomography is an indicator of epidermal hyperplasia and dermal edema within inflamed skin
      Psoriasis is a common inflammatory skin disease resulting from genetic and environmental alterations of cutaneous immune responses. While numerous therapeutic targets involved in the immunopathogenesis of psoriasis have been identified, the in vivo dynamics of inflammation in psoriasis remain unclear. We undertook in vivo time course focus-tracked optical coherence tomography (OCT) imaging to noninvasively document cutaneous alterations in mouse skin treated topically with Imiquimod (IMQ), an established model of a psoriasis-like disease. Quantitative appraisal of dermal architectural changes was achieved through a two parameter fit of OCT axial scans in the dermis of the form A(x, y, z) = ρ ...
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    23. Parametric imaging of cancer with optical coherence tomography

      Parametric imaging of cancer with optical coherence tomography
      We present a parametric optical coherence tomography (OCT) technique to improve contrast between malignant and healthy non-neoplastic tissue. The technique incorporates a fully automated method to extract tissue attenuation characteristics. Results are represented visually as a parametric en face image, where the parameter used for contrast is indicative of the relative optical attenuation coefficient of the tissue. We present the first parametric OCT images of human lymph nodes containing malignant cells, and demonstrate improved tissue contrast over en face OCT images.
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    24. Non-destructive label-free monitoring of collagen gel remodeling using optical coherence tomography

      Non-destructive label-free monitoring of collagen gel remodeling using optical coherence tomography
      Matrix remodeling plays a fundamental role in physiological and pathological processes, as well as in tissue engineering applications. In this paper, optical coherence tomography (OCT), a non-destructive optical imaging technology, was used to image collagen gel remodeling by smooth muscle cells (SMCs). The optical scattering properties of collagen–SMC gels were characterized quantitatively by fitting OCT data to a theoretical model. Matrix remodeling over 5 days produced a 10-fold increase in the reflectivity of the collagen gels, corresponding to a decrease in scattering anisotropy from 0.91 to 0.46. The increase in reflectivity was corroborated in confocal mosaic images ...
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    1-24 of 32 1 2 »
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    1. (30 articles) Oregon Health & Science University
    2. (30 articles) Steven L. Jacques
    3. (14 articles) Ruikang K. Wang
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    5. (12 articles) University of Washington
    6. (9 articles) David Levitz
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    The effect of wavelength on optical properties extracted from images of engineered tissue Optically characterizing collagen gels made with different cell types Quantitative characterization of developing collagen gels using optical coherence tomography Parametric imaging of cancer with optical coherence tomography A differentially amplified motion in the ear for near-threshold sound detection Feature Of The Week 5/27/11: Researchers Utilize Optical Coherence Tomography to Perform in vivo Investigation into the Process of Hearing Feature Of The Week 07/01/12: Enhanced Optical Clearing of Skin In Vivo and OCT In-Depth Imaging Feature Of The Week 3/17/13: Using Optical Coherence Tomography to Study Mechanisms of Hearing Feature Of The Week 03/05/2017: In Vivo Imaging of Coral Tissue and Skeleton with Optical Coherence Tomography Line-field confocal optical coherence tomography-Practical applications in dermatology and comparison with established imaging methods Optical coherence tomography detection of changes in inner retinal and choroidal thicknesses in patients with early retinitis pigmentosa Feasibility of combined optical coherence tomography and autofluorescence imaging for visualization of needle biopsy placement