1. Featured Articles

    25-48 of 51 « 1 2 3 »
    1. Volumetric full-range magnetomotive optical coherence tomography

      Volumetric full-range magnetomotive optical coherence tomography

      Magnetomotive optical coherence tomography (MM-OCT) can be utilized to spatially localize the presence of magnetic particles within tissues or organs. These magnetic particle-containing regions are detected by using the capability of OCT to measure small-scale displacements induced by the activation of an external electromagnet coil typically driven by a harmonic excitation signal. The constraints imposed by the scanning schemes employed and tissue viscoelastic properties limit the speed at which conventional MM-OCT data can be acquired. Realizing that electromagnet coils can be designed to exert MM force on relatively large tissue volumes (comparable or larger than typical OCT imaging fields of ...

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    2. Intraoperative long range optical coherence tomography as a novel method of imaging the pediatric upper airway before and after adenotonsillectomy

      Intraoperative long range optical coherence tomography as a novel method of imaging the pediatric upper airway before and after adenotonsillectomy

      Background/Objectives While upper airway obstruction is a common problem in the pediatric population, the first-line treatment, adenotonsillectomy, fails in up to 20% of patients. The decision to proceed to surgery is often made without quantitative anatomic guidance. We evaluated the use of a novel technique, long-range optical coherence tomography (LR-OCT), to image the upper airway of children under general anesthesia immediately before and after tonsillectomy and/or adenoidectomy. We investigated the feasibility of LR-OCT to identify both normal anatomy and sites of airway narrowing and to quantitatively compare airway lumen size in the oropharyngeal and nasopharyngeal regions pre- and ...

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    3. Computed Optical Margin Assessment for Breast Cancer Surgery, Phase I (Part B)

      Computed Optical Margin Assessment for Breast Cancer Surgery, Phase I (Part B)

      This intraoperative study is a prospective study analyzing specimens from fifty subjects. Patients scheduled to undergo breast- conserving surgery will be recruited in accordance with the inclusion and exclusion criteria. The study period per subject is the time it takes to assess the ex vivo breast tissue sample using the study device. Image review will be conducted during surgery and compared to the margin status findings in the post-operative pathology report.

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    4. Intraoperative optical coherence tomography imaging to identify parathyroid glands

      Intraoperative optical coherence tomography imaging to identify parathyroid glands

      Objective Optical coherence tomography (OCT) is a non-invasive high-resolution imaging technique that permits characterization of microarchitectural features in real time. Previous ex vivo studies have shown that the technique is capable of distinguishing between parathyroid tissue, thyroid tissue, lymph nodes, and adipose tissue. The purpose of this study was to evaluate the practicality of OCT during open and minimally invasive parathyroid and thyroid surgery. Methods During parathyroid and thyroid surgery, OCT images were generated from parathyroid glands, thyroid tissue, lymph nodes, and adipose tissue. The images were immediately assessed by the operating team using the previously defined criteria. Second, the ...

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    5. Development of an integrated optical coherence tomography-gas nozzle system for surgical laser ablation applications: preliminary findings of in situ spinal cord deformation due to gas flow effects

      Development of an integrated optical coherence tomography-gas nozzle system for surgical laser ablation applications: preliminary findings of in situ spinal cord deformation due to gas flow effects

      Gas assisted laser machining of materials is a common practice in the manufacturing industry. Advantages in using gas assistance include reducing the likelihood of flare-ups in flammable materials and clearing away ablated material in the cutting path. Current surgical procedures and research do not take advantage of this and in the case for resecting osseous tissue, gas assisted ablation can help minimize charring and clear away debris from the surgical site. In the context of neurosurgery, the objective is to cut through osseous tissue without damaging the underlying neural structures. Different inert gas flow rates used in laser machining could ...

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    6. Degree of polarization uniformity with high noise immunity using polarization-sensitive optical coherence tomography

      Degree of polarization uniformity with high noise immunity using polarization-sensitive optical coherence tomography

      A new metric representing polarization uniformity is presented. Noise corrected degree of polarization uniformity (DOPU) is computed from polarization-sensitive optical coherence tomography (OCT), and selectively visualizes tissue with the multiple scattering, such as highly pigmented tissues. The new metric is designed to be minimally sensitive to systematic additive noise. The performance of this new metric is analyzed by numerical simulation and in vivo human retinal imaging, using Jones matrix OCT. The new metric exhibited only a small dependency on the signal-to-noise ratio. Selective in vivo visualization of pigmented tissues in the human retina is demonstrated, with cross sectional and en-face ...

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    7. Long-range Fourier domain optical coherence tomography of the pediatric subglottis

      Long-range Fourier domain optical coherence tomography of the pediatric subglottis

      Background Acquired subglottic stenosis (SGS) most commonly results from prolonged endotracheal intubation and is a diagnostic challenge in the intubated child. At present, no imaging modality allows for in vivo characterization of subglottic microanatomy to identify early signs of acquired SGS while the child remains intubated. Fourier domain optical coherence tomography (FD-OCT) is a minimally invasive, light-based imaging modality which provides high resolution, three dimensional (3D) cross-sectional images of biological tissue. We used long-range FD-OCT to image the subglottis in intubated pediatric patients undergoing minor head and neck surgical procedures in the operating room. Methods A long-range FD-OCT system and ...

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    8. Ultrahigh speed endoscopic optical coherence tomography for gastroenterology

      Ultrahigh speed endoscopic optical coherence tomography for gastroenterology

      We describe an ultrahigh speed endoscopic swept source optical coherence tomography (OCT) system for clinical gastroenterology using a vertical-cavity surface-emitting laser (VCSEL) and micromotor imaging catheter. The system had a 600 kHz axial scan rate and 8 µm axial resolution in tissue. Imaging was performed with a 3.2 mm diameter imaging catheter at 400 frames per second with a 12 µm spot size. Three-dimensional OCT (3D-OCT) imaging was performed in patients with a cross section of pathologies undergoing upper and lower endoscopy. The use of distally actuated imaging catheters enabled OCT imaging with more flexibility, such as volumetric imaging ...

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    9. Detection and characterisation of biopsy tissue using quantitative optical coherence elastography (OCE) in men with suspected prostate cancer

      Detection and characterisation of biopsy tissue using quantitative optical coherence elastography (OCE) in men with suspected prostate cancer

      We present first quantitative three-dimensional (3D) data sets recorded using optical coherence elastography (OCE) for the diagnosis and detection of prostate cancer (PCa). 120 transrectal ultrasound guided prostate biopsy specimens from 10 men suspected with prostate cancer were imaged using OCE. 3D quantitative mechanical assessment of biopsy specimens obtained in kilopascals (kPa) at an interval of 40 µm was compared with histopathology. Sensitivity, specificity, and positive and negative predictive values were calculated for OCE in comparison to histopathology. The results show OCE imaging could reliably differentiate between benign prostate tissue, acinar atypical hyperplasia, prostatic intraepithelial neoplasia and malignant PCa. The ...

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    10. Effect of Atorvastatin Therapy on Fibrous Cap Thickness in Coronary Atherosclerotic Plaque as Assessed by Optical Coherence Tomography The EASY-FIT Study

      Effect of Atorvastatin Therapy on Fibrous Cap Thickness in Coronary Atherosclerotic Plaque as Assessed by Optical Coherence Tomography The EASY-FIT Study

      Background The detailed mechanism of plaque stabilization by statin therapy is not fully understood. Objectives The aim of this study was to assess the effect of lipid-lowering therapy with 20 mg/day of atorvastatin versus 5 mg/day of atorvastatin on fibrous cap thickness in coronary atherosclerotic plaques by using optical coherence tomography (OCT). Methods Seventy patients with unstable angina pectoris and untreated dyslipidemia were randomized to either 20 mg/day or 5 mg/day of atorvastatin therapy. OCT was performed to assess intermediate nonculprit lesions at baseline and 12-month follow-up. Results Serum low-density lipoprotein cholesterol level was significantly lower ...

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    11. Leading Irish University Bio-Photonics Laboratory And Compact Imaging Extend Agreement For Innovative Research Collaboration

      Leading Irish University Bio-Photonics Laboratory And Compact Imaging Extend Agreement For Innovative Research Collaboration

      NUI Galway’s TOMI Lab Provides Globally-Recognized Scientific Leadership for Advanced Development of Company’s Mobile OCT Technology The National University of Ireland Galway (NUI Galway) ( www.nuigalway.com.ie ) and Compact Imaging, Inc. (CI) ( www.compactimaging.com ) today jointly announced the extension of their innovative research collaboration in the field of optical coherence tomography (OCT) for a variety of applications, including mobile health monitoring and identity verification. The research agreement will continue the advanced development of CI’s novel multiple reference OCT sensor technology, MRO™, very small, low cost, low operating power OCT architecture ideal for high volume mobile ...

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

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

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

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    13. Depth-encoded all-fiber swept source polarization sensitive OCT

      Depth-encoded all-fiber swept source polarization sensitive OCT

      Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of conventional OCT and can assess depth-resolved tissue birefringence in addition to intensity. Most existing PS-OCT systems are relatively complex and their clinical translation remains difficult. We present a simple and robust all-fiber PS-OCT system based on swept source technology and polarization depth-encoding. Polarization multiplexing was achieved using a polarization maintaining fiber. Polarization sensitive signals were detected using fiber based polarization beam splitters and polarization controllers were used to remove the polarization ambiguity. A simplified post-processing algorithm was proposed for speckle noise reduction relaxing the demand for phase stability. We ...

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    14. Optical coherence elastography for tissue characterization: a review

      Optical coherence elastography for tissue characterization: a review

      Optical coherence elastography (OCE) represents the frontier of optical elasticity imaging techniques and focuses on the micro-scale assessment of tissue biomechanics in 3D that is hard to achieve with traditional elastographic methods. Benefit from the advancement of optical coherence tomography, and driven by the increasing requirements in nondestructive biomechanical characterization, this emerging technique recently has experienced a rapid development. In this paper, we start with the description of the mechanical contrast that has been employed by OCE and review the state-of-the-art techniques based on the reported applications and discuss the current technical challenges, emphasizing the unique role of OCE in ...

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    15. Monte Carlo modeling of angiographic optical coherence tomography

      Monte Carlo modeling of angiographic optical coherence tomography

      Optical coherence tomography (OCT) provides both structural and angiographic imaging modes. Because of its unique capabilities, OCT-based angiography has been increasingly adopted into small animal and human subject imaging. To support the development of the signal and image processing algorithms on which OCT-based angiography depends, we describe here a Monte Carlo-based model of the imaging approach. The model supports arbitrary three-dimensional vascular network geometries and incorporates methods to simulate OCT signal temporal decorrelation. With this model, it will be easier to compare the performance of existing and new angiographic signal processing algorithms, and to quantify the accuracy of vascular segmentation ...

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    16. Trimodality imaging system and intravascular endoscopic probe: combined optical coherence tomography, fluorescence imaging and ultrasound imaging

      Trimodality imaging system and intravascular endoscopic probe: combined optical coherence tomography, fluorescence imaging and ultrasound imaging

      In this Letter, we present a trimodality imaging system and an intravascular endoscopic probe for the detection of early-stage atherosclerotic plaques. The integrated system is able to acquire optical coherence tomography (OCT), fluorescence, and ultrasound images and simultaneously display them in real time. A trimodality intravascular endoscopic probe of 1.2 mm in diameter and 7 mm in length was fabricated based on a dual-modality optical probe that integrates OCT and fluorescence imaging functions and a miniature ultrasound transducer. The probe is capable of rotating at up to 600 rpm. Ex vivo images from rabbit aorta and human coronary arteries ...

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    17. Quantitative elasticity measurement of urinary bladder wall using laser-induced surface acoustic waves

      Quantitative elasticity measurement of urinary bladder wall using laser-induced surface acoustic waves

      The maintenance of urinary bladder elasticity is essential to its functions, including the storage and voiding phases of the micturition cycle. The bladder stiffness can be changed by various pathophysiological conditions. Quantitative measurement of bladder elasticity is an essential step toward understanding various urinary bladder disease processes and improving patient care. As a nondestructive, and noncontact method, laser-induced surface acoustic waves (SAWs) can accurately characterize the elastic properties of different layers of organs such as the urinary bladder. This initial investigation evaluates the feasibility of a noncontact, all-optical method of generating and measuring the elasticity of the urinary bladder. Quantitative ...

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    18. Breathing laser as an inertia-free swept source for high-quality ultrafast optical bioimaging

      Breathing laser as an inertia-free swept source for high-quality ultrafast optical bioimaging

      We demonstrate an all-fiber breathing laser as inertia-free swept source (BLISS), with an ultra-compact design, for the emerging ultrafast bioimaging modalities. The unique feature of BLISS is its broadband wavelength-swept operation ( ∼ 60     nm ) with superior temporal stability in terms of both long term (0.08 dB over 27 h) and shot-to-shot power variations (2.1%). More importantly, it enables a wavelength sweep rate of > 10     MHz ( ∼ 7 × 10 8     nm / s )—orders-of-magnitude faster than the existing swept sources based on mechanical or electrical tuning techniques. BLISS thus represents a practical and new generation of swept source operating in the unmet ...

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    19. Institute of Physics and University of Manchester Optical Coherence Tomography II Meeting December 3rd Manchester UK

      Institute of Physics and University of Manchester Optical Coherence Tomography II Meeting December 3rd Manchester UK

      We invite you to join us for an exciting day discussing recent developments in optical coherence tomography (OCT). This follows on our successful meeting in 2011. We hope this meeting will be of interest to a broad audience coming from industry, clinics and academia. Send us your talk and poster abstracts! Topics include, but are not limited to: Clinical applications of OCT (e.g. ophthalmology, cardiology, dermatology) Industrial applications of OCT (e.g. nondestructive testing) Life science applications in OCT (e.g. cell biology, tissue engineering) Multimodal applications including OCT (e.g. combination of fluorescence, Raman and OCT) Biophotonics themes ...

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    20. Microanatomy of the tympanic membrane in chronic myringitis obtained with optical coherence tomography

      Microanatomy of the tympanic membrane in chronic myringitis obtained with optical coherence tomography

      A microscope-based optical coherence tomography (OCT) device was used to assess the microanatomy of the tympanic membrane in patients with chronic myringitis. A prospective study was designed for this purpose. OCT measurements of the tympanic membrane were done on 11 patients with myringitis with a microscope-based spectral domain OCT system. The in vivo findings were compared with those findings of a control group consisting of 36 patients with retraction pockets or atrophic tympanic membranes ( n = 13), myringosclerosis ( n = 12) and perforations ( n = 11). In active chronic myringitis, the thickness of the tympanic membrane is increased compared to healthy membranes and ...

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    21. Macrophages and intravascular optical coherence tomography bright spots: a quantitative study

      Macrophages and intravascular optical coherence tomography bright spots: a quantitative study

      Objectives We hypothesized that bright spots in intravascular optical coherence tomography (IVOCT) images may originate by co-localization of plaque materials of differing indices of refraction (IR). To quantitatively identify bright spots, we developed an algorithm that accounts for factors including tissue depth, distance from light source, and signal-to-noise ratio. We used this algorithm to perform a bright spot analysis of IVOCT images, and compared these results with histologic examination of matching tissue sections. Background Although bright spots are thought to represent macrophages in IVOCT images, studies of alternative etiologies have not been reported. Methods Fresh human coronary arteries (n=14 ...

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    22. Optical coherence tomography in the 2um wavelength regime for paint and other high opacity materials

      Optical coherence tomography in the 2um wavelength regime for paint and other high opacity materials

      An optical coherence tomography system using a compact fiber source emitting amplified spontaneous emission at central wavelength of 1960 nm with bandwidth of 40 nm is developed to enhance the probing depth in a highly scattering material with low water content. Examples of application to paint are used to demonstrate significantly improved penetration depth in high opacity materials in the 2-μm wavelength regime.

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    23. Low coherence interferometry approach for aiding fine needle aspiration biopsie

      Low coherence interferometry approach for aiding fine needle aspiration biopsie

      We present portable preclinical low-coherence interference (LCI) instrumentation for aiding fine needle aspiration biopsies featuring the second-generation LCI-based biopsy probe and an improved scoring algorithm for tissue differentiation. Our instrument and algorithm were tested on 38 mice with cultured tumor mass and we show the specificity, sensitivity, and positive predictive value of tumor detection of over 0.89, 0.88, and 0.96, respectively.

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    24. Three-dimensional motion correction using speckle and phase for in vivo computed optical interferometric tomography

      Three-dimensional motion correction using  speckle and phase for in vivo computed optical  interferometric tomography

      Over the years, many computed optical interferometric techniques have been developed to perform high-resolution volumetric tomography. By utilizing the phase and amplitude information provided with interferometric detection, post-acquisition corrections for defocus and optical aberrations can be performed. The introduction of the phase, though, can dramatically increase the sensitivity to motion (most prominently along the optical axis). In this paper, we present two algorithms which, together, can correct for motion in all three dimensions with enough accuracy for defocus and aberration correction in computed optical interferometric tomography. The first algorithm utilizes phase differences within the acquired data to correct for motion ...

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    25-48 of 51 « 1 2 3 »
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