Articles from SPIE Digital Library

1. Combined image-processing algorithms for improved optical coherence tomography of prostate nerves

   Explore Article SPIE Digital Library (Aug 20 2010) Urology

   Cavernous nerves course along the surface of the prostate gland and are responsible for erectile function. These nerves are at risk of injury during surgical removal of a cancerous prostate gland. In this work, a combination of segmentation, denoising, and edge detection algorithms are applied to time-domain optical coherence tomography (OCT) images of rat prostate to improve identification of cavernous nerves. First, OCT images of the prostate are segmented to differentiate the cavernous nerves from the prostate gland. Then, a locally adaptive denoising algorithm using a dual-tree complex wavelet transform is applied to reduce speckle noise. Finally, edge detection is ... (Read Full Article)
   

   Comment on Article Mentions:   Nathaniel M. Fried   Shahab Chitchian   Johns Hopkins University

2. Parametric imaging of cancer with optical coherence tomography

   Explore Article SPIE Digital Library (Aug 19 2010) Oncology

   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. (Read Full Article)
   

   Comment on Article Mentions:   University of Western Australia   Steven L. Jacques   Loretta Scolaro

3. Comparison of optical coherence tomography, microcomputed tomography, and histology at a three-dimensionally imaged trabecular bone sample

   Explore Article SPIE Digital Library (Aug 16 2010)

   We investigate optical coherence tomography (OCT) as a method for imaging bone. The OCT images are compared directly to those of the standard methods of bone histology and microcomputed tomography (µCT) on a single, fixed human femoral trabecular bone sample. An advantage of OCT over bone histology is its noninvasive nature. OCT also images the lamellar structure of trabeculae at slightly higher contrast than normal bone histology. While µCT visualizes the trabecular framework of the whole sample, OCT can image additionally cells with a penetration depth limited approximately to 1 mm. The most significant advantage of OCT, however, is the ... (Read Full Article)
   

   Comment on Article Mentions:   Catholic University of Leuven   Christoph Kasseck   Marita Kratz

4. Intravascular optical coherence tomography on a beating heart model

   Explore Article SPIE Digital Library (Aug 9 2010) Cardiology

   The advantages and limitations of using a beating heart model in the development of intravascular optical coherence tomography are discussed. The model fills the gap between bench experiments, performed on phantoms and excised arteries, and whole animal in-vivo preparations. The beating heart model is stable for many hours, allowing for extended measurement times and multiple imaging sessions under in-vivo conditions without the complications of maintaining whole-animal preparation. The perfusate supplying the heart with nutrients can be switched between light scattering blood to a nonscattering perfusate to allow the optical system to be optimized without the need of an efficient blood ... (Read Full Article)
   

   Comment on Article Mentions:   Guy Lamouche   Marc L. Dufour   Sebastien Vergnole

5. Improving image segmentation performance and quantitative analysis via a computer-aided grading methodology for optical coherence tomography retinal image analysis

   Explore Article SPIE Digital Library (Aug 9 2010) Ophthalmology

   We demonstrate quantitative analysis and error correction of optical coherence tomography (OCT) retinal images by using a custom-built, computer-aided grading methodology. A total of 60 Stratus OCT (Carl Zeiss Meditec, Dublin, California) B-scans collected from ten normal healthy eyes are analyzed by two independent graders. The average retinal thickness per macular region is compared with the automated Stratus OCT results. Intergrader and intragrader reproducibility is calculated by Bland-Altman plots of the mean difference between both gradings and by Pearson correlation coefficients. In addition, the correlation between Stratus OCT and our methodology-derived thickness is also presented. The mean thickness difference between ... (Read Full Article)
   

   Comment on Article Mentions:   Zeiss Stratus OCT   Harry M. Salinas   Mount Sinai School of Medicine

6. In-vivo dynamic characterization of microneedle skin penetration using optical coherence tomography

   Explore Article SPIE Digital Library (Aug 6 2010) Dermatology , Probes

   The use of microneedles as a method of circumventing the barrier properties of the stratum corneum is receiving much attention. Although skin disruption technologies and subsequent transdermal diffusion rates are being extensively studied, no accurate data on depth and closure kinetics of microneedle-induced skin pores are available, primarily due to the cumbersome techniques currently required for skin analysis. We report on the first use of optical coherence tomography technology to image microneedle penetration in real time and in vivo. We show that optical coherence tomography (OCT) can be used to painlessly measure stratum corneum and epidermis thickness, as well as ... (Read Full Article)
   

   Comment on Article Mentions:   University of Limerick

7. In vivo volumetric imaging of the human upper eyelid with ultrahigh-resolution optical coherence tomography

   Explore Article SPIE Digital Library (Aug 5 2010)

   The upper eyelid is a biological tissue with complex structure, essential for the maintenance of an optically clear ocular surface due to its physical (blinking) effect. The Meibomian glands (MGs) are structures that lie beneath the surface of the inner eyelid and are partially responsible for the production of the superficial oily layer of the tear film. The MGs are only superficially visible under magnification when the eyelid is everted. We present for the first time in vivo 3-D images of healthy and inflamed human MGs. Tomograms were acquired from the tarsal plate of everted human eyelids with a 1060-nm ... (Read Full Article)
   

   Comment on Article Mentions:   Luigina Sorbara   University of Waterloo   Kostadinka K. Bizheva

8. Combined optical coherence tomography and electroretinography system for in vivo simultaneous morphological and functional imaging of the rodent retina

   Explore Article SPIE Digital Library (Aug 4 2010) Ophthalmology

   A combined ultrahigh resolution optical coherence tomography (UHROCT) and a electroretinography (ERG) system is presented for simultaneous imaging of the retinal structure and physiological response to light stimulation in the rodent eye. The 1060-nm UHROCT system provides ~3×5 µm (axial×lateral) resolution in the rat retina and time resolution of 22 µs. A custom-designed light stimulator integrated into the UHROCT imaging probe provides light stimuli with user-selected color, duration, and intensity. The performance of the combined system is demonstrated in vivo in healthy rats, and in a rat model of drug-induced outer retinal degeneration. Experimental results show correlation between the observed ... (Read Full Article)
   

   Comment on Article Mentions:   University of Toronto   University of Waterloo   Kostadinka K. Bizheva

9. High-speed optical coherence imaging: towards the structure and the physiology of living tissue

   Explore Article SPIE Digital Library (Aug 2 2010)

   Recently rapid development of ultrahigh speed optical coherence tomography (OCT) instruments have been observed. This imaging modality enables performing cross-sectional in vivo imaging of biological samples with speeds of more than 100,000,000 axial scans per second. This progress has been achieved by the introduction of Fourier domain detection techniques to OCT instruments. High-speed imaging capabilities lifts the primary limitation of early OCT technology by giving access to in vivo 3-D volumetric reconstructions in large scales within reasonable time constraints. New perspectives for existing OCT applications has been added by creating new instrumentation including the functional imaging. The latter shows a ... (Read Full Article)
   

   Comment on Article Mentions:   Maciej Wojtkowski   Nicolaus Copernicus University   Andrzej A. Kowalczyk

10. In vivo functional retinal optical coherence tomography

    Explore Article SPIE Digital Library (Jul 23 2010) Ophthalmology

    An experimental design for noninvasive assessment of neural retinal tissue function with enhanced sensitivity is presented. By matching the response detection to a defined flicker frequency stimulus similar to heterodyne detection, the response signal will be shifted out of the low-frequency noise and the specificity of response detection will be strongly enhanced. Optimal measurement parameters are discussed, such as the function and timing of the response function to a single flash stimulus. The results indicate responses on the order of 200 ms that have been probed with our frequency-encoded approach using 5 Hz flickering. Preliminary results indicate the feasibility of ... (Read Full Article)
    

    Comment on Article Mentions:   Medical University of Vienna   Tilman Schmoll   Rainer A. Leitgeb

11. Signal power decrease due to fringe washout as an extension of the limited Doppler flow measurement range in spectral domain optical coherence tomography

    Explore Article SPIE Digital Library (Jul 23 2010) Doppler

    The recently introduced new phase-dependent Doppler model for spectral domain optical coherence tomography (SD OCT) has shown that the simple linear relation between the Doppler phase shift and the axial velocity component of an obliquely moving sample is not valid. Additionally, for nearly transverse sample motion with high velocities the phase shift will approach a constant value. Consequently, for small Doppler angles the velocity measurement range of the phase-resolved Doppler analysis is limited in SD OCT. Since these undesirable small Doppler angles can not be prevented, for example, in the in vivo 3-D measurement, we introduce a novel method extending ... (Read Full Article)
    

    Comment on Article Mentions:   Julia Walther   Dresden University of Technology   Henning Morawietz

12. Highly reproducible swept-source, dispersion-encoded full-range biometry and imaging of the mouse eye

    Explore Article SPIE Digital Library (Jul 20 2010) Ophthalmology

    We report a high-speed, dispersion-encoded, full-range (DEFR) swept-source optical coherence tomography system for in vivo ocular imaging and biometry of small animals. The fast DEFR algorithm removes the depth ambiguity, gives access to objects located at the zero delay position, and doubles the sampling depth to 2×5.0 mm (at −101 to −71 dB sensitivity) in a single scan using 2048 samples/depth scan 0.43 nm line width of a light source operating at 1056 nm with 70 nm tuning range. The acquisition speed (frames of 512 depth scans in 18.3 ms) permits precise on-line monitoring during positioning and provides cross-sectional views ... (Read Full Article)
    

    Comment on Article Mentions:   Medical University of Vienna   Bernd M. Hofer   Cardiff University

13. Toward guidance of epicardial cardiac radio frequency ablation therapy using optical coherence tomography

    Explore Article SPIE Digital Library (Jul 7 2010) Cardiology

    Radiofrequency ablation (RFA) is the standard of care to cure many cardiac arrhythmias. Epicardial ablation for the treatment of ventricular tachycardia has limited success rates due in part to the presence of epicardial fat, which prevents proper rf energy delivery, inadequate contact of ablation catheter with tissue, and increased likelihood of complications with energy delivery in close proximity to coronary vessels. A method to directly visualize the epicardial surface during RFA could potentially provide feedback to reduce complications and titrate rf energy dose by detecting critical structures, assessing probe contact, and confirming energy delivery by visualizing lesion formation. Currently, there ... (Read Full Article)
    

    Comment on Article Mentions:   Case Western Reserve University   Christine P. Fleming   Andrew M. Rollins

14. Quantitative tool for rapid disease mapping using optical coherence tomography images of azoxymethane-treated mouse colon

    Explore Article SPIE Digital Library (Jul 7 2010) Gastroenterology

    Amy M. Winkler, Photini F. S. Rice, Rebekah A. Drezek et al. Optical coherence tomography (OCT) can provide new insight into disease progression and therapy by enabling nondestructive, serial imaging of in vivo cancer models. In previous studies, we have shown the utility of endoscopic OCT for identifying adenomas in the azoxymethane-treated mouse model of co ... [J. Biomed. Opt. 15, 041512 (2010)] published Wed Jul 7, 2010. (Read Full Article)
    

    Comment on Article Mentions:   Jennifer K. Barton   Rice University   Amy M. Winkler

15. Real-time monitoring of cardiac radio-frequency ablation lesion formation using an optical coherence tomography forward-imaging catheter

    Explore Article SPIE Digital Library (Jul 1 2010) Cardiology

    Radio-frequency ablation (rfa) is the standard of care for the treatment of cardiac arrhythmias; however, there are no direct measures of the successful delivery of ablation lesions. Optical coherence tomography (OCT) imaging has the potential to provide real-time monitoring of cardiac rfa therapy, visualizing lesion formation and assessing tissue contact in the presence of blood. A rfa-compatible forward-imaging conical scanning probe is prototyped to meet this need. The forward-imaging probe provides circular scanning, with a 2-mm scan diameter and 30-µm spot size. During the application of rf energy, dynamics are recorded at 20 frames per second with a 40-kHz A-line ... (Read Full Article)
    

    Comment on Article Mentions:   Hui Wang   Christine P. Fleming   Andrew M. Rollins

16. Volumetric in vivo imaging of intracochlear microstructures in mice by high-speed spectral domain optical coherence tomography

    Explore Article SPIE Digital Library (Jun 30 2010) Otolaryngology

    There is considerable interest in developing new methods for in vivo imaging of the complex anatomy of the mammalian cochlea for clinical as well as fundamental studies. In this study, we explored, the feasibility of spectral domain optical coherence tomography (SD-OCT) for 3-D in vivo imaging of the cochlea in mice. The SD-OCT system employed in this study used a broadband light source centered at 1300 nm, and the imaging speed of the system was 47,000 A-scans per second using the InGaAs camera. The system was capable of providing fully processed, high-resolution B-scan images [512 (axial)×128 (lateral) pixels] at 280 ... (Read Full Article)
    

    Comment on Article Mentions:   Hrebesh M. Subhash   Oregon Health & Science University   Ruikang K. Wang

17. Imaging port wine stains by fiber optical coherence tomography

    Explore Article SPIE Digital Library (Jun 15 2010) Dermatology

    We develop a fiber optical coherence tomography (OCT) system in the clinical utility of imaging port wine stains (PWS). We use our OCT system on 41 patients with PWS to document the difference between PWS skin and contralateral normal skin. The system, which operates at 4 frames/s with axial and transverse resolutions of 10 and 9 µm, respectively, in the skin tissue, can clearly distinguish the dilated dermal blood vessels from normal tissue. We present OCT images of patients with PWS and normal human skin. We obtain the structural parameters, including epidermal thickness and diameter and depth of dilated blood ... (Read Full Article)
    

    Comment on Article

18. Jade detection and analysis based on optical coherence tomography images

    Explore Article SPIE Digital Library (Jun 15 2010) NDE/NDT , Other Non-Medical

    Optical coherence tomography is a fundamentally new type of optical sensing technology that can perform high-resolution, cross sectional sensing of the internal structure of materials and biological samples. This work briefly describes its capability of exploring and analyzing the internal structures and textures of various jades. With a depth resolution of 4 µm in jade and penetration range of 5 mm in jade, swept-source OCT could be used as a new powerful instrument to generate 3-D volume data of jade, which is important for applications in jade industry and artwork, particularly for jade detection and classification, counterfeit recognition, and guided ... (Read Full Article)
    

    Comment on Article Mentions:   Shoude Chang   Costel Flueraru   National Research Council Canada

19. In vitro study of ultrasound and different-concentration glycerolinduced changes in human skin optical attenuation assessed with optical coherence tomography

    Explore Article SPIE Digital Library (Jun 3 2010) Dermatology

    Previous studies have demonstrated the ultrasound-induced skin optical clearing enhancement with topical application of 60% glycerol (G) on in vitro porcine skin and in vivo human skin. Our purpose was to find the relation between the effect of optical skin clearing and different concentrations of glycerol and to find more effective ultrasound-glycerol combinations on optical skin clearing. The enhancement effect of ultrasound [Sonophoresis (SP) delivery] in combination with 40% G, 60% G, and 80% G on in vitro human skin optical clearing was investigated. Light imaging depths of skin were measured using optical coherence tomography. Different concentrations of glycerol and ... (Read Full Article)
    

    Comment on Article

20. Real-time resampling in Fourier domain optical coherence tomography using a graphics processing unit

    Explore Article SPIE Digital Library (Jun 3 2010)

    Fourier domain optical coherence tomography (FD-OCT) requires either a linear-in-wavenumber spectrometer or a computationally heavy software algorithm to recalibrate the acquired optical signal from wavelength to wavenumber. The first method is sensitive to the position of the prism in the spectrometer, while the second method drastically slows down the system speed when it is implemented on a serially oriented central processing unit. We implement the full resampling process on a commercial graphics processing unit (GPU), distributing the necessary calculations to many stream processors that operate in parallel. A comparison between several recalibration methods is made in terms of performance and ... (Read Full Article)
    

    Comment on Article Mentions:   Adrian G. Podoleanu   University of Kent   Adrian Bradu

21. Virtual four-dimensional imaging of lung parenchyma by optical coherence tomography in mice

    Explore Article SPIE Digital Library (May 20 2010) Pulmonology

    In this feasibility study, we present a method for virtual 4-D imaging of healthy and injured subpleural lung tissue in the ventilated mouse. We use triggered swept source optical coherence tomography (OCT) with an A-scan frequency of 20 kHz to image murine subpleural alveoli during the inspiratory phase. The data acquisition is gated to the ventilation pressure to take single B-scans in each respiration cycle for different pressure levels. The acquired B-scans are combined off-line into one volume scan for each pressure level. The air fraction in healthy lungs and injured lungs is measured using 2-D OCT en-face images. Upon ... (Read Full Article)
    

    Comment on Article Mentions:   Sven Meissner   Dresden University of Technology   Edmund Koch

22. Dispersion compensation for optical coherence tomography

    Explore Article SPIE Digital Library (May 19 2010)

    Optical coherence tomography (OCT) is an imaging technique widely used in various applications especially in biomedical field. It constructs a high resolution 3-D image using multiple cross-sectional views. The axial resolution can be degraded if the sample is dispersive, which is usually true as most of the samples are living tissues. For time-domain OCT, this dispersion is minimized numerically by introducing a compensation filter, which is applied to the obtained signal in Wigner domain, a time-frequency domain. The filter is designed using simulated annealing optimization technique. This paper shows the design of the filter and the results of dispersion compensation. (Read Full Article)
    

    Comment on Article Mentions:   Sherif S. Sherif   University of Manitoba

23. Optical coherence tomography as approach for the minimal invasive localization of the germinal disc in ovo before chicken sexing

    Explore Article SPIE Digital Library (May 18 2010) Developmental Biology

    In most industrial states a huge amount of newly hatched male layer chickens are usually killed immediately after hatching by maceration or gassing. The reason for killing most of the male chickens of egg producing races is their slow growth rate compared to races specialized on meat production. When the egg has been laid, the egg contains already a small disc of cells on the surface of the yolk known as the blastoderm. This region is about 4 - 5 mm in diameter and contains the information whether the chick becomes male or female and hence allows sexing of the ... (Read Full Article)
    

    Comment on Article Mentions:   Edmund Koch   Dresden University of Technology

24. Real time optical coherence tomography monitoring of Candida albicans biofilm in vitro during photodynamic therapy study

    Explore Article SPIE Digital Library (May 18 2010)

    The biofilm formed by Candida albicans is the mainly cause of infections associated to medical devices such as catheters. Studies have shown that photodynamic antimicrobial therapy (PAT) has lethal effect on C. albicans, and it is based on photosensitizer (PS) in the presence of low intensity light to generate reactive oxygen species in biological systems. The aim of this study was to analyze in real time, by Optical Coherence Tomography (OCT), the alterations in C. albicans biofilm in vitro during PAT using methylene blue (MB) as a PS and red light. An OCT system with working at 930nm was used, ... (Read Full Article)
    

    Comment on Article

1-24 of 627 // 1 2 3 4 ... 25 26 27 »