Articles from SPIE Digital Library

1. Ultra-high speed full range complex spectral domain optical coherence tomography for volumetric imaging at 140,000 A scans per second

   Explore Article SPIE Digital Library (Mar 11 2010) Ophthalmology

   We demonstrate an ultra-high speed full rang spectral domain optical coherence tomography system based on CMOS camera at 140,000 A-scans per second. By implementing beam-offset method, a constant modulation frequency is introduced into each B-scan that enables the reconstruction of the full range complex SDOCT images from in vivo biological specimens. To make use of the full acquisition capacity of detection camera used in the system, we developed system control software that streams the raw spectral fringe data directly into the computer memory. The feasibly of our high speed full range SDOCT system is demonstrated for imaging the dynamics of ... (Read Full Article)
   

   Comment on Article Mentions:   Ruikang K. Wang   Lin An   Oregon Health & Science University

2. 3D reconstruction of the optic nerve head using stereo fundus images for computer-aided diagnosis of glaucoma

   Explore Article SPIE Digital Library (Mar 9 2010) Ophthalmology

   The shape of the optic nerve head (ONH) is reconstructed automatically using stereo fundus color images by a robust stereo matching algorithm, which is needed for a quantitative estimate of the amount of nerve fiber loss for patients with glaucoma. Compared to natural scene stereo, fundus images are noisy because of the limits on illumination conditions and imperfections of the optics of the eye, posing challenges to conventional stereo matching approaches. In this paper, multi scale pixel feature vectors which are robust to noise are formulated using a combination of both pixel intensity and gradient features in scale space. Feature ... (Read Full Article)
   

   Comment on Article Mentions:   Michael D. Abramoff   Young H. Kwon   Kyungmoo Lee

3. Automatic lumen segmentation from intravascular OCT images

   Explore Article SPIE Digital Library (Mar 9 2010) Cardiology

   In the last decade intravascular optical coherence tomography has known a tremendous progress. Its high resolution (5- 10µm) allows coronary plaque characterization, vulnerable plaque assessment, and the guidance of intravascular interventions. However, one intravascular OCT sequence contains hundreds of frames, and their interpretation requires a lot of time and energy. Therefore, there is a strong need for automated segmentation algorithms to process this large amount of data. In this article, we present an automated algorithm to extract lumen contours from images obtained with intravascular Optical Coherence Tomography (OCT). Unlike existing methods, our algorithm requires no post- or preprocessing of the ... (Read Full Article)
   

   Comment on Article Mentions:   Ecole Polytechnique de Montréal   Guy Lamouche   National Research Council Canada

4. Morphological characterization of dental prostheses interfaces using optical coherence tomography

   Explore Article SPIE Digital Library (Mar 9 2010) Dentistry

   Fixed partial prostheses as integral ceramic, polymers, metal-ceramic or metal-polymers bridges are mainly used in the frontal part of the dental arch (especially the integral bridges). They have to satisfy high stress as well as esthetic requirements. The masticatory stress may induce fractures of the bridges. These may be triggered by initial materials defects or by alterations of the technological process. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. Dental interfaces represent one of the most significant aspects in the strength of the dental prostheses under the masticatory load. ... (Read Full Article)
   

   Comment on Article Mentions:   Adrian Bradu   Cosmin Sinescu   Adrian G. Podoleanu

5. Adhesive improvement in optical coherence tomography combined with confocal microscopy for class V cavities investigations

   Explore Article SPIE Digital Library (Mar 9 2010) Dentistry

   The purpose of this study is to present a non invasive method for the marginal adaptation evaluation in class V composite restorations. Standardized class V cavities prepared in human extracted teeth were filled with composite resin (Premise, Kerr). The specimens were thermocycled. The interfaces were examined by Optical Coherence Tomography (OCT) combined with confocal microscopy and fluorescence. The optical configuration uses two single mode directional couplers with a superluminiscent diode as the source at 1300 nm. The scanning procedure is similar to that used in any confocal microscope, where the fast scanning is en-face (line rate) and the depth scanning ... (Read Full Article)
   

   Comment on Article Mentions:   Cosmin Sinescu   George M. Dobre   Adrian G. Podoleanu

6. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

   Explore Article SPIE Digital Library (Mar 9 2010) Ophthalmology

   Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from ... (Read Full Article)
   

   Comment on Article Mentions:   Michael D. Abramoff   Kyungmoo Lee   University of Iowa

7. Automated 3D segmentation of intraretinal layers from optic nerve head optical coherence tomography images

   Explore Article SPIE Digital Library (Mar 9 2010) Ophthalmology

   Optical coherence tomography (OCT), being a noninvasive imaging modality, has begun to find vast use in the diagnosis and management of ocular diseases such as glaucoma, where the retinal nerve fiber layer (RNFL) has been known to thin. Furthermore, the recent availability of the considerably larger volumetric data with spectral-domain OCT has increased the need for new processing techniques. In this paper, we present an automated 3-D graph-theoretic approach for the segmentation of 7 surfaces (6 layers) of the retina from 3-D spectral-domain OCT images centered on the optic nerve head (ONH). The multiple surfaces are detected simultaneously through the ... (Read Full Article)
   

   Comment on Article Mentions:   Michael D. Abramoff   Kyungmoo Lee   University of Iowa

8. High-sensitive blood flow imaging of the retina and choroid by using double-beam optical coherence angiography

   Explore Article SPIE Digital Library (Mar 5 2010) Ophthalmology , Doppler

   Wide-field and high-sensitive Doppler optical coherence angiography of the posterior human eye has been demonstrated. High-sensitive phase-resolved spectral-domain optical coherence tomography using the superluminescent diode with the central wavelength of 840 nm and bandwidth of 50 nm (FWHM) is developed. Two OCT signals with a time separation are acquired simultaneously with double sampling beams divided by using a Wollaston prism and a polarization-sensitive spectrometer consisting of two line scan cameras. The total power of two beams on the cornea is 700 µW. The line scan rate of cameras is 27 kHz and each OCT channel has the sensitivity of 93 ... (Read Full Article)
   

   Comment on Article Mentions:   Shuichi Makita   Yoshiaki Yasuno   Masahiro Miura

9. Imaging natural occlusal caries lesions with optical coherence tomography

   Explore Article SPIE Digital Library (Mar 5 2010) Dentistry

   Several studies have demonstrated that polarization-sensitive optical coherence tomography (PS-OCT) can be used to nondestructively measure the severity of demineralization in the important occlusal surfaces. The purpose of this study was to assess the potential of PS-OCT and OCT methods for the measurement of the depth of natural occlusal carious lesions. Teeth were screened for potential occlusal lesions using near infrared imaging (NIR). A PS-OCT system operating at 1310-nm was used to acquire polarization resolved images of the area of interest on the occlusal surface. The teeth were serial sectioned to 200 µm thickness and examined with polarized light microscopy ... (Read Full Article)
   

   Comment on Article Mentions:   Daniel S. Fried   Cynthia L. Darling   UCSF

10. Imaging early demineralization with PS-OCT

    Explore Article SPIE Digital Library (Mar 5 2010) Dentistry

    New methods are needed for the nondestructive measurement of tooth demineralization and remineralization to monitor the progression of incipient caries lesions (tooth decay) for effective nonsurgical intervention and to evaluate the performance of anti-caries treatments such as chemical treatments or laser irradiation. Studies have shown that optical coherence tomography (OCT) has great potential to fulfill this role since it can be used to measure the depth and severity of early lesions with an axial resolution exceeding 10-µm, it is easy to apply in vivo and it can be used to image the convoluted topography of tooth occlusal surfaces. In this ... (Read Full Article)
    

    Comment on Article Mentions:   Daniel S. Fried   Cynthia L. Darling   UCSF

11. Imaging simulated secondary caries lesions with cross polarization OCT

    Explore Article SPIE Digital Library (Mar 5 2010) Dentistry

    The clinical diagnosis of secondary caries has been found to account for the replacement of the majority of intra-coronal restorations. Current methods to diagnose the presence of these lesions at early stages are considered insufficient due to their low sensitivity. Polarization-sensitive optical coherence tomography (PS-OCT) imaging studies have confirmed its effectiveness for imaging carious subsurface lesions in enamel and dentin. The objective of this study was to determine if PS-OCT can be used to nondestructively image demineralization through resin restorations on extracted teeth with both simulated and natural lesions. Simulated secondary caries lesions were created by exposing cavity preparations made ... (Read Full Article)
    

    Comment on Article Mentions:   Daniel S. Fried   UCSF

12. Clinical studies of frequency domain optical coherence tomography in the coronary arteries: the first 200 patients

    Explore Article SPIE Digital Library (Mar 4 2010) Cardiology

    We report clinical study results of three-dimensional (3D) in vivo imaging of human coronary arteries using frequency domain optical coherence tomography (FD-OCT). At the time of this report, over 2000 patients in over 10 countries have been imaged using FD-OCT systems and disposable fiberoptic catheters developed by LightLab Imaging Inc. The first commercial versions of the systems were introduced in Europe in May 2009. The system operates at 50,000 axial lines/s, performing a 50 mm spiral pullback in 2.5 seconds with a rotational frame rate of 100 Hz. The commercial system employs a proprietary micro-cavity swept laser, allowing imaging of ... (Read Full Article)
    

    Comment on Article Mentions:   LightLab Imaging   Desmond C. Adler   Joseph M. Schmitt

13. Near-IR polarization imaging of sound and carious dental enamel

    Explore Article SPIE Digital Library (Mar 4 2010) Dentistry

    A thorough understanding of how polarized near-IR light propagates through sound and carious dental hard tissues is important for the development of dental optical imaging systems. New optical imaging tools for the detection and assessment of dental caries (dental decay) such as near-IR imaging and optical coherence tomography can exploit the enhanced contrast provided by polarization sensitivity. In this investigation, an automated system was developed to collect images for the full 16-element Mueller Matrix. The polarized light was controlled by linear polarizers and liquid crystal retarders and the 36 images were acquired as the polarized near-IR light propagates through the ... (Read Full Article)
    

    Comment on Article Mentions:   Daniel S. Fried   Cynthia L. Darling   UCSF

14. Analysis of dental abfractions by optical coherence tomography

    Explore Article SPIE Digital Library (Mar 4 2010) Dentistry

    im and objectives. Abfraction is the pathological loss of cervical hard tooth substance caused by biomechanical overload. High horizontal occlusal forces result in large stress concentrations in the cervical region of the teeth. These stresses may be high enough to cause microfractures in the dental hard tissues, eventually resulting in the loss of cervical enamel and dentin. The present study proposes the microstructural characterization of these cervical lesions by en face optical coherence tomography (eFOCT). Material and methods: 31 extracted bicuspids were investigated using eFOCT. 24 teeth derived from patients with active bruxism and occlusal interferences; they presented deep buccal ... (Read Full Article)
    

    Comment on Article Mentions:   Adrian G. Podoleanu   Adrian Bradu   State University of New York at Buffalo

15. In vivo, dual-modality imaging of mouse eyes: optical coherence tomography and photoacoustic microscopy within a single instrument

    Explore Article SPIE Digital Library (Mar 2 2010) Microscopy , Ophthalmology

    Optical-resolution photoacoustic microscopy (OR-PAM) provides superb optical absorption contrast for red blood cells (RBCs), which makes it ideal for in vivo microvasculature imaging. In comparison, optical coherence tomography (OCT), widely used for tissue microstructure imaging, provides high optical scattering contrast. The two contrast mechanisms are highly complementary. In this work, we combined OR-PAM and OCT into a single, dual-modality imaging instrument for in vivo mouse eye imaging. We demonstrated in vivo dual-modality imaging of the anterior segment of mouse eyes with laser pulse energy within the ANSI laser safety standard. (Read Full Article)
    

    Comment on Article Mentions:   Li Li   Lihong V. Wang   Konstantin I. Maslov

16. Segmentation of ophthalmic optical coherence tomography images using graph cuts

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology

    We describe an efficient approach for the automated segmentation of pathological/morphological structures in ophthalmic Spectral Domain Optical Coherence Tomography (SDOCT) images. In this algorithm, image pixels are treated as nodes of a graph with edge weights assigned to associate pairs of pixels. The weights vary according to the distances, brightness differences, and feature variations between pixel pairs. Cuts through the graph with minimum accumulated weights correspond to morphological layer boundaries. This approach has been applied to SDOCT images with encouraging results and thus forms an adaptable framework for the segmentation of many different ophthalmic structures. (Read Full Article)
    

    Comment on Article Mentions:   Cynthia A. Toth   Joseph A. Izatt   Duke University

17. Ultrahigh-speed volumetric ophthalmic OCT imaging at 800nm and 1050nm

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology , Tunable Sources

    The performance and imaging characteristics of ultrahigh speed ophthalmic optical coherence tomography (OCT) are investigated. In vivo imaging results are obtained at 850nm and 1050nm using different configurations of spectral and swept source / Fourier domain OCT. A spectral / Fourier domain instrument using a high speed CMOS linescan camera with SLD light source centered at 850nm achieves speeds of ~91,000 axial scans per second with ~3µm axial resolution in tissue. A spectral / Fourier domain instrument using an InGaAs linescan camera with SLD light source centered at 1050nm achieves ~47,000 axial scans per second with ~7µm resolution in tissue. ... (Read Full Article)
    

    Comment on Article Mentions:   Massachusetts Institute of Technology   Thorlabs   Iwona Gorczyńska

18. Spectrally encoded confocal scanning laser ophthalmoscope

    Explore Article SPIE Digital Library (Mar 2 2010) Microscopy , Ophthalmology

    Fundus imaging has become an essential clinical diagnostic tool in ophthalmology. Current generation scanning laser ophthalmoscopes (SLO) offer advantages over conventional fundus photography and indirect ophthalmoscopy in terms of light efficiency and contrast. As a result of the ability of SLO to provide rapid, continuous imaging of retinal structures and its versatility in accommodating a variety of illumination wavelengths, allowing for imaging of both endogenous and exogenous fluorescent contrast agents, SLO has become a powerful tool for the characterization of retinal pathologies. However, common implementations of SLO, such as the confocal scanning laser ophthalmoscope (CSLO) and line-scanning laser ophthalmoscope (LSLO), ... (Read Full Article)
    

    Comment on Article Mentions:   Joseph A. Izatt   Duke University

19. Structural and biochemical characterization of the rat retina with combined Raman spectroscopy-optical coherence tomography (RS-SDOCT)

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology

    Raman spectroscopy (RS) and Optical Coherence Tomography (OCT) are powerful tools for optical analysis of tissues with complimentary strengths. OCT excels and visualizing tissue microstructure while RS can relay tissue biochemical composition. Both instruments have significant potential to serve as valuable tools in non-invasive characterization of the rodent models of retinal disease. In this abstract we present the design and application of a common detector combined RS-OCT instrument for evaluating the morphological and biochemical differences in a rat model for oxygen induced retinopathy. Rat pups that have undergone a variable oxygen treatment are compared to rats raised in room air. ... (Read Full Article)
    

    Comment on Article Mentions:   Anita Mahadevan-Jansen   Ton G. van Leeuwen   Dirk J. Faber

20. Imaging of mouse embryonic eye development using optical coherence tomography

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology

    Congenital abnormalities are often caused by genetic disorders which alter the normal development of the eye. Embryonic eye imaging in mouse model is important for understanding of normal and abnormal eye development and can contribute to prevention and treatment of eye defects in humans. In this study, we used Swept Source Optical Coherence Tomography (SS-OCT) to image eye structure in mouse embryos at 12.5 to 17.5 days post coitus (dpc). The imaging depth of the OCT allowed us to visualize the whole eye globe at these stages. Different ocular tissues including lens, cornea, eyelids, and hyaloid vasculature were visualized. These ... (Read Full Article)
    

    Comment on Article Mentions:   Kirill V. Larin   Baylor College of Medicine   University of Houston

21. Small animal ocular biometry using optical coherence tomography

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology

    A custom-built OCT system was used to obtain images of the whole mouse eye. We developed a semi-automated segmentation method to detect the boundaries of the anterior and posterior corneal, lens and retinal surfaces as well as the anterior surface of the iris. The radii of curvature of the surfaces were calculated using a conic section fit of each boundary. Image distortions due to refraction of the OCT beam at the successive boundaries were corrected using a ray-tracing algorithm. Corrected ocular distances, radii of curvature of the cornea and lens surfaces, and anterior chamber angle were obtained on 3 C57BL/6J ... (Read Full Article)
    

    Comment on Article Mentions:   Marco B. Ruggeri   Fabrice Manns   University of Miami

22. Imaging retinal nerve fiber bundles at ultrahigh-speed and ultrahigh-resolution using OCT with adaptive optics

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology

    Ultrahigh speed line scan detectors based on CMOS technology have been recently demonstrated in ultrahigh resolution spectral-domain optical coherence tomography (UHR-SD-OCT) for retinal imaging. While successful, fundamental tradeoffs exist been image acquisition time, image sampling density, and sensitivity, all of which impact the extent of motion artifacts, visualization of fine spatial detail, and detection of faint reflections. Here we investigate these tradeoffs for imaging retinal nerve fiber bundles (RNFBs) using UHR-SD-OCT with adaptive optics (AO). Volume scans of 3°x3° and 1.5°x1.5° were acquired at retinal locations of 3° nasal and 6° superior to the fovea on a healthy subject. Dynamic ... (Read Full Article)
    

    Comment on Article Mentions:   Barry Cense   Donald T. Miller   Indiana University

23. Retinal imaging with a combined adaptive optics/optical coherence tomography and adaptive optics/scanning laser ophthalmoscopy system

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology

    We describe results of retinal imaging with a novel instrument that combines adaptive optics - Fourier-domain optical coherence tomography (AO-OCT) with an adaptive optics scanning laser ophthalmoscope (AO-SLO). One of the benefits of combining Fd-OCT with SLO includes automatic co-registration between the two imaging modalities and the potential for correcting lateral and transversal eye motion resulting in motion artifact-free volumetric retinal imaging. Additionally this allows for direct comparison between retinal structures that can be imaged with both modalities (e.g., photoreceptor mosaics or microvasculature maps). This dual imaging modality could provide insight into some retinal properties that could not be accessed ... (Read Full Article)
    

    Comment on Article Mentions:   UC Davis   Robert J. Zawadzki   Lawrence Livermore National Laboratory

24. Quantification of retinal lesions by polarization sensitive optical coherence tomography

    Explore Article SPIE Digital Library (Mar 2 2010) Ophthalmology

    Segmentation of retinal structures is an important step for quantitative diagnostic applications of optical coherence tomography (OCT) in ophthalmology. Contrary to previous segmentation algorithms that are based on intensity images, we use the tissue specific contrast provided by polarization sensitive (PS) OCT for segmentation of retinal layers and lesions. Our algorithms exploit the polarization scrambling property of the retinal pigment epithelium (RPE) in a first step to segment the RPE. The RPE is then used as a "backbone" to identify further structures like the normal RPE position (indicating Bruch's membrane) or the posterior tips of the photoreceptors. In a final ... (Read Full Article)
    

    Comment on Article Mentions:   Michael Pircher   Erich Gotzinger   Bernhard Baumann

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