1. 1-12 of 12
    1. Patch-based denoising method using low-rank technique and targeted database for optical coherence tomography image

      Patch-based denoising method using low-rank technique and targeted database for optical coherence tomography image

      Image denoising is a crucial step before performing segmentation or feature extraction on an image, which affects the final result in image processing. In recent years, utilizing the self-similarity characteristics of the images, many patch-based image denoising methods have been proposed, but most of them, named the internal denoising methods, utilized the noisy image only where the performances are constrained by the limited information they used. We proposed a patch-based method, which uses a low-rank technique and targeted database, to denoise the optical coherence tomography (OCT) image. When selecting the similar patches for the noisy patch, our method combined internal ...

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    2. Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography

      Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography

      The aim of this study was to evaluate the signal intensity and signal attenuation of swept source optical coherence tomography (SS-OCT) for dental caries in relation to the variation of mineral density. SS-OCT observation was performed on the enamel and dentin artificial demineralization and on natural caries. The artificial caries model on enamel and dentin surfaces was created using Streptococcus mutans biofilms incubated in an oral biofilm reactor. The lesions were centrally cross sectioned and SS-OCT scans were obtained in two directions to construct a three-dimensional data set, from the lesion surface (sagittal scan) and parallel to the lesion surface ...

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    3. Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

      Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

      Evidence suggests high-resolution, high-contrast, 100    frames / s 100  frames/s intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and three-dimensional (3-D) registration methods to provide validation of IVOCT pullback volumes using microscopic, color, and fluorescent cryo-image volumes with optional registered cryo-histology. A specialized registration method matched IVOCT pullback images acquired in the catheter reference frame to a true 3-D cryo-image volume. Briefly, an 11-parameter registration model including a polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition ...

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    4. Processing to determine optical parameters of atherosclerotic disease from phantom and clinical intravascular optical coherence tomography three-dimensional pullbacks

      Processing to determine optical parameters of atherosclerotic disease from phantom and clinical intravascular optical coherence tomography three-dimensional pullbacks

      Analysis of intravascular optical coherence tomography (IVOCT) data has potential for real-time in vivo plaque classification. We developed a processing pipeline on a three-dimensional local region of support for estimation of optical properties of atherosclerotic plaques from coronary artery, IVOCT pullbacks. Using realistic coronary artery disease phantoms, we determined insignificant differences in mean and standard deviation estimates between our pullback analyses and more conventional processing of stationary acquisitions with frame averaging. There was no effect of tissue depth or oblique imaging on pullback parameter estimates. The method’s performance was assessed in comparison with observer-defined standards using clinical pullback data ...

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    5. Modulation of retinal image vasculature analysis to extend utility and provide secondary value from optical coherence tomography imaging

      Modulation of retinal image vasculature analysis to extend utility and provide secondary value from optical coherence tomography imaging

      Retinal image analysis is emerging as a key source of biomarkers of chronic systemic conditions affecting the cardiovascular system and brain. The rapid development and increasing diversity of commercial retinal imaging systems present a challenge to image analysis software providers. In addition, clinicians are looking to extract maximum value from the clinical imaging taking place. We describe how existing and well-established retinal vasculature segmentation and measurement software for fundus camera images has been modulated to analyze scanning laser ophthalmoscope retinal images generated by the dual-modality Heidelberg SPECTRALIS ® instrument, which also features optical coherence tomography.

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    6. Assessment of cervical demineralization induced by Streptococcus mutans using swept-source optical coherence tomography

      Assessment of cervical demineralization induced by Streptococcus mutans using swept-source optical coherence tomography

      Exposed root surfaces due to gingival recession are subject to biofilm stagnation that can result in caries formation. Cervical enamel and dentin demineralization induced by a cariogenic biofilm was evaluated using swept-source optical coherence tomography (SS-OCT). The cementoenamel junction (CEJ) sections of extracted human teeth were subjected to demineralization for 1, 2, or 3 weeks. A suspension of Streptococcus mutans was applied to form a cariogenic biofilm using an oral biofilm reactor. After incubation, demineralization was observed by SS-OCT. For the analysis of SS-OCT signal, the value of the area under the curve (AUC) of the signal profile was measured ...

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    7. Prostate cancer diagnosis: the feasibility of needle-based optical coherence tomography

      Prostate cancer diagnosis: the feasibility of needle-based optical coherence tomography

      The objective of this study is to demonstrate the feasibility of needle-based optical coherence tomography (OCT) and functional analysis of OCT data along the full pullback trajectory of the OCT measurement in the prostate, correlated with pathology. OCT images were recorded using a commercially available C7-XR™ OCT Intravascular Imaging System interfaced to a C7 Dragonfly™ intravascular 0.9-mm-diameter imaging probe. A computer program was constructed for automated image attenuation analysis. First, calibration of the OCT system for both the point spread function and the system roll-off was achieved by measurement of the OCT signal attenuation from an extremely weakly scattering ...

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    8. Automated working distance adjustment enables optical coherence tomography of the human larynx in awake patients

      Automated working distance adjustment enables optical coherence tomography of the human larynx in awake patients

      Optical coherence tomography (OCT) provides structural information of laryngeal tissue which is comparable to histopathological analysis of biopsies taken under general anesthesia. In awake patients, movements impede clinically useful OCT acquisition. Therefore, an automatic compensation of movements was implemented into a swept source OCT-laryngoscope. Video and OCT beam path were combined in one tube of 10-mm diameter. Segmented OCT images served as distance sensor and a feedback control adjusted the working distance between 33 and 70 mm by synchronously translating the reference mirror and focusing lens. With this motion compensation, the tissue was properly visible in up to 88% of ...

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    9. Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

      Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

      A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography ( μ CT ) for assessment of natural enamel lesions in vitro . Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In μ CT , the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of ...

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    10. Parameter estimation of atherosclerotic tissue optical properties from three-dimensional intravascular optical coherence tomography

      Parameter estimation of atherosclerotic tissue optical properties from three-dimensional intravascular optical coherence tomography

      We developed robust, three-dimensional methods, as opposed to traditional A-line analysis, for estimating the optical properties of calcified, fibrotic, and lipid atherosclerotic plaques from in vivo coronary artery intravascular optical coherence tomography clinical pullbacks. We estimated attenuation μ t and backscattered intensity I 0 from small volumes of interest annotated by experts in 35 pullbacks. Some results were as follows: noise reduction filtering was desirable, parallel line (PL) methods outperformed individual line methods, root mean square error was the best goodness-of-fit, and α -trimmed PL ( α -T-PL) was the best overall method. Estimates of μ t were calcified ( 3.84 ± 0.95     mm − 1 ...

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    11. Diagnostic potential of multimodal imaging of ovarian tissue using optical coherence tomography and second-harmonic generation microscopy

      Diagnostic potential of multimodal imaging of ovarian tissue using optical coherence tomography and second-harmonic generation microscopy

      Ovarian cancer is particularly deadly because it is usually diagnosed after it has metastasized. We have previously identified features of ovarian cancer using optical coherence tomography (OCT) and second-harmonic generation (SHG) microscopy (targeting collagen). OCT provides an image of the ovarian microstructure, while SHG provides a high-resolution map of collagen fiber bundle arrangement. Here, we investigated the diagnostic potential of dual-modality OCT and SHG imaging. We conducted a fully crossed, multireader, multicase study using seven human observers. Each observer classified 44 ex vivo mouse ovaries (16 normal and 28 abnormal) as normal or abnormal from OCT, SHG, and simultaneously viewed ...

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    12. Clinical cross-polarization optical coherence tomography assessment of subsurface enamel below dental resin composite restorations

      Clinical cross-polarization optical coherence tomography assessment of subsurface enamel below dental resin composite restorations

      A newly designed intraoral swept source cross-polarization optical coherence tomography (CP-OCT) imaging system was used to examine the integrity of the subsurface enamel below resin composite restorations placed in primary teeth. CP-OCT analysis was performed using images obtained from resin composite restoration in 62 ( n = 62 ) pediatric subjects. Clinical examination was performed by a single examiner prior to CP-OCT imaging and analysis. CP-OCT images are presented using a unique combined intensity image, where a false color scale is overlaid on the grayscale intensity image. There was a clear difference in the distribution of the mean-backscattered intensity (mR) between restorations recently ...

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    1-12 of 12
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