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OCT Images (oct + image)
Selected AbstractsAM,FM techniques in the analysis of optical coherence tomography signalsJOURNAL OF BIOPHOTONICS, Issue 6-7 2009Costas Pitris Abstract The subtle tissue changes associated with the early stages of malignancies, such as cancer, are not clearly discernible even at the current, improved, resolution of optical coherence tomography (OCT) systems. However, these changes directly affect the spectral content of the OCT image that contains information regarding these unresolvable features. Spectral analysis of OCT signals has recently been shown to provide additional information, resulting in improved contrast, directly related to scatterer size changes. Amplitude modulation,frequency modulation (AM,FM) analysis, a fast and accurate technique for the estimation of the instantaneous frequency, phase, and amplitude of a signal, can also be applied to OCT images to extract scatterer-size information. The proposed technique could make available an extremely valuable tool for the investigation of disease characteristics that now remain below the resolution of OCT and could significantly improve the technology's diagnostic capabilities. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fully automatic three-dimensional quantitative analysis of intracoronary optical coherence tomography,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 7 2009Method, Validation Abstract Objectives and background: Quantitative analysis of intracoronary optical coherence tomography (OCT) image data (QOCT) is currently performed by a time-consuming manual contour tracing process in individual OCT images acquired during a pullback procedure (frame-based method). To get an efficient quantitative analysis process, we developed a fully automatic three-dimensional (3D) lumen contour detection method and evaluated the results against those derived by expert human observers. Methods: The method was developed using Matlab (The Mathworks, Natick, MA). It incorporates a graphical user interface for contour display and, in the selected cases where this might be necessary, editing. OCT image data of 20 randomly selected patients, acquired with a commercially available system (Lightlab imaging, Westford, MA), were pulled from our OCT database for validation. Results: A total of 4,137 OCT images were analyzed. There was no statistically significant difference in mean lumen areas between the two methods (5.03 ± 2.16 vs. 5.02 ± 2.21 mm2; P = 0.6, human vs. automated). Regression analysis showed a good correlation with an r value of 0.99. The method requires an average 2,5 sec calculation time per OCT image. In 3% of the detected contours an observer correction was necessary. Conclusion: Fully automatic lumen contour detection in OCT images is feasible with only a select few contours showing an artifact (3%) that can be easily corrected. This QOCT method may be a valuable tool for future coronary imaging studies incorporating OCT. © 2009 Wiley-Liss, Inc. [source] Assessment of Optical Coherence Tomography Imaging in the Diagnosis of Non-Melanoma Skin Cancer and Benign Lesions Versus Normal Skin: Observer-Blinded Evaluation by Dermatologists and PathologistsDERMATOLOGIC SURGERY, Issue 6 2009METTE MOGENSEN MD BACKGROUND Optical coherence tomography (OCT) is an optical imaging technique that may be useful in diagnosis of non-melanoma skin cancer (NMSC). OBJECTIVES To describe OCT features in NMSC such as actinic keratosis (AK) and basal cell carcinoma (BCC) and in benign lesions and to assess the diagnostic accuracy of OCT in differentiating NMSC from benign lesions and normal skin. METHODS AND MATERIALS OCT and polarization-sensitive (PS) OCT from 104 patients were studied. Observer-blinded evaluation of OCT images from 64 BCCs, 1 baso-squamous carcinoma, 39 AKs, two malignant melanomas, nine benign lesions, and 105 OCT images from perilesional skin was performed; 50 OCT images of NMSC and 50 PS-OCT images of normal skin were evaluated twice. RESULTS Sensitivity was 79% to 94% and specificity 85% to 96% in differentiating normal skin from lesions. Important features were absence of well-defined layering in OCT and PS-OCT images and dark lobules in BCC. Discrimination of AK from BCC had an error rate of 50% to 52%. CONCLUSION OCT features in NMSC are identified, but AK and BCC cannot be differentiated. OCT diagnosis is less accurate than clinical diagnosis, but high accuracy in distinguishing lesions from normal skin, crucial for delineating tumor borders, was obtained. [source] AM,FM techniques in the analysis of optical coherence tomography signalsJOURNAL OF BIOPHOTONICS, Issue 6-7 2009Costas Pitris Abstract The subtle tissue changes associated with the early stages of malignancies, such as cancer, are not clearly discernible even at the current, improved, resolution of optical coherence tomography (OCT) systems. However, these changes directly affect the spectral content of the OCT image that contains information regarding these unresolvable features. Spectral analysis of OCT signals has recently been shown to provide additional information, resulting in improved contrast, directly related to scatterer size changes. Amplitude modulation,frequency modulation (AM,FM) analysis, a fast and accurate technique for the estimation of the instantaneous frequency, phase, and amplitude of a signal, can also be applied to OCT images to extract scatterer-size information. The proposed technique could make available an extremely valuable tool for the investigation of disease characteristics that now remain below the resolution of OCT and could significantly improve the technology's diagnostic capabilities. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Quantification of glycerol diffusion in human normal and cancer breast tissues in vitro with optical coherence tomographyLASER PHYSICS LETTERS, Issue 4 2010H.Q. Zhong Abstract Optical coherence tomography (OCT) holds great promise as a routine research tool for analysis of identifying the boundaries between normal and diseased breast tissue in vitro and in vivo. However, despite the depth penetration afforded by this imaging modality, light attenuation in tissues imposes limitations. Here we studied the optical clearing effect of glycerol in human cancer and normal breast tissues with OCT for functional imaging to monitor. Depth- and time-resolved profiles for OCT signal enhancement were presented. The results show that the OCT imaging depth and imaging contrast of breast tissues have been improved after application of 60% glycerol in the 2-D OCT images. The OCT slope signals of breast tissues decreased as glycerol diffusion into tissues, therefore, the water and intercellular fluids were drawn out from tissues. Then the reverse process due to water was drawn back into the cells as a result of its affinity for water. The permeability coefficient of 60% glycerol was (3.14 ± 0.07) × 10,5 cm/s in breast cancer tissues, and (0.89 ± 0.02) × 10,5 cm/s in normal breast tissues, respectively. The permeability coefficient of glycerol in cancer tissues was 3.54-fold than that in normal tissues. These results demonstrate that the optical clearing of normal and cancer breast tissues are improved after application of glycerol. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Histology of highly echolucent regions in optical coherence tomography images from two patients with sirolimus-eluting stent restenosis,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 6 2010Hiroyuki Nagai MD Abstract We report on two patients with sirolimus-eluting stent (SES) restenosis lesions who showed highly echolucent regions by optical coherence tomography (OCT) and who could be assessed histologically after removal by directional coronary atherectomy (DCA). One restenosis lesion had a bilayer structure of hyperechoic outer layers and highly echolucent inner layers on OCT images and histologically exhibited myxomatous neointima tissue in the highly echolucent regions; another restenosis case showed patchy and highly echolucent regions throughout the layers and its histology revealed fibrin thrombosis. We should be aware that patterns of echolucent on OCT images may have various histology. OCT allows the visualization of fine lesions that conventional intravascular ultrasound (IVUS) cannot provide. The OCT images of drug-eluting stent restenosis lesions often show echolucent regions [Shuzoh et al., EuroInterv 2006;1:484]. However, no histological study of the lesions has been reported to date. Here we report on two patients with SES restenosis lesions that showed highly echolucent regions by OCT and that could be assessed histologically after removal by DCA. © 2009 Wiley-Liss, Inc. [source] Fully automatic three-dimensional quantitative analysis of intracoronary optical coherence tomography,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 7 2009Method, Validation Abstract Objectives and background: Quantitative analysis of intracoronary optical coherence tomography (OCT) image data (QOCT) is currently performed by a time-consuming manual contour tracing process in individual OCT images acquired during a pullback procedure (frame-based method). To get an efficient quantitative analysis process, we developed a fully automatic three-dimensional (3D) lumen contour detection method and evaluated the results against those derived by expert human observers. Methods: The method was developed using Matlab (The Mathworks, Natick, MA). It incorporates a graphical user interface for contour display and, in the selected cases where this might be necessary, editing. OCT image data of 20 randomly selected patients, acquired with a commercially available system (Lightlab imaging, Westford, MA), were pulled from our OCT database for validation. Results: A total of 4,137 OCT images were analyzed. There was no statistically significant difference in mean lumen areas between the two methods (5.03 ± 2.16 vs. 5.02 ± 2.21 mm2; P = 0.6, human vs. automated). Regression analysis showed a good correlation with an r value of 0.99. The method requires an average 2,5 sec calculation time per OCT image. In 3% of the detected contours an observer correction was necessary. Conclusion: Fully automatic lumen contour detection in OCT images is feasible with only a select few contours showing an artifact (3%) that can be easily corrected. This QOCT method may be a valuable tool for future coronary imaging studies incorporating OCT. © 2009 Wiley-Liss, Inc. [source] 2113: AO imaging in AMDACTA OPHTHALMOLOGICA, Issue 2010N MASSAMBA Purpose Two different systems, adaptive optics scanning laser ophthalmoscope (AOSLO), and Spectral Domain Ophtalmoloscopy (SD-OCT) were used to visualize cones in the outer neurosensory retina overlying soft macular drusen and the surrounding retinal areas. Methods High resolution images were obtained with Adaptive Optics (AO) in addition to complete ophthalmic examination including BCVA on ETDRS chart, biomicroscopic examination, autofluorescence imaging, fluorescein and indocyanine angiographies (HRA2 Heidelberg ,Germany) and SD-OCT. The AO image are then compared with conventional infrared and SD-OCT. Soft macular drusen from 50 patients (age between 65 and 85) visible on the scanning laser ophthalmoscope(SLO) examination were evaluated included in the study Results The soft drusen were visible in AO images as generally round areas delimited by a peripheral low-reflectance line. The highly reflective photoreceptor inner/outer segment junction (IS/OS) can be used as a pattern of photoreceptors integrity in SD-OCT images. In areas where the IS/OS junction is absent on SD-OCT, no cones are visualized in registered AOSLO images. In the inner area of many drusen, hyper reflective spots of a size between 2 and 15 µm were sometimes isolated, sometimes grouped into tight aggregates of 2 to 40 components. Cone photoreceptors were visible in areas between drusen in most AO images, however the mosaic image sharpness was significantly less uniform in these elderly patients than previously observed in younger, healthy retinas. Conclusion This study shows the synergistic nature of these two high-resolution retinal imaging systems The microscopic characteristics of soft drusen on AO imaging suggest some analogy with the anatomopathologic characteristics. AO technology will be a powerful tool to refine their clinical classification [source] Intravitreal pegaptanib sodium (Macugen®) for diabetic macular oedemaACTA OPHTHALMOLOGICA, Issue 6 2009Giuseppe Querques Abstract. Purpose:, To report the functional and anatomical outcomes resulting from the use of intravitreal pegaptanib sodium (Macugen®) in patients with diabetic macular oedema (DMO). Methods:, We conducted a retrospective outcome analysis, by optical coherence tomography (OCT) and best-corrected visual acuity (BCVA), of eyes with DMO treated with intravitreal pegaptanib sodium. Moreover, we evaluated the foveal transverse photoreceptor (PR) band integrity in the OCT images at the time of the last follow-up visit. Results:, Sixty-three eyes of 48 patients with a minimum of 6 months of follow-up were included for analysis. Intravitreal pegaptanib was found to produce significant improvements in mean BCVA (p = 0.019) and reductions in mean central macular thickness (CMT) (p < 0.001) as soon as the 6-week follow-up. Most eyes (60/63) required a mean of 3.03 ± 0.9 repeated treatments, over a mean follow-up period of 6.7 ± 1.2 months, to achieve significant improvements in mean BCVA (p < 0.001) and mean CMT (p < 0.001). In our series, the lower visual acuities tended to congregate in the group with the less-defined PR band (p < 0.001) and the lower CMT tended to congregate in the group with the best-defined PR band (p = 0.04), even though the higher CMT did not tend to congregate in the group with the less-defined PR band. Conclusion:, Our findings demonstrate that selective inhibition by intravitreal pegaptanib sodium of vascular endothelial growth factor (VEGF)-165 may produce a clinically meaningful and statistically significant benefit in the treatment of DMO. [source] Segmentation of FD-OCT images shows selective loss of inner retinal layers in patients with DM and no or early DRACTA OPHTHALMOLOGICA, Issue 2009FD VERBRAAK Purpose Determine whether diabetes differentially affects specific retinal layers by comparing the thickness of six retinal layers in diabetic patients with no or minimal diabetic retinopathy (DR) to age- and gender-matched normal controls. Methods Forty-four patients with type 1 diabetes and no or minimal DR underwent full ophthalmic examination, stereoscopic fundus photographs and spectral domain optical coherence tomography (OCT). Following automated segmentation of intraretinal layers of the OCT images, mean thickness was calculated for 6 individual layers of the retina in the fovea, the pericentral area and the peripheral area of the central macula and compared to an age- and gender-matched control group. Results In type 1 diabetic patients with minimal DR, the retinal nerve fiber layer (p=0.00) and the ganglion cell/inner plexiform layer (p=0.02) were significantly thinner compared to age- and gender-matched controls. No other layers showed a significant difference. Conclusion Thinning of the total retina in diabetic patients with minimal DR relative to normal controls is due to a selective thinning of inner retinal layers and supports the concept that early DR includes a neuro-degenerative component. [source] Slitlamp integrated OCT, what you can see, is what you can scanACTA OPHTHALMOLOGICA, Issue 2009FD VERBRAAK Purpose To present results of OCT images captured of the posterior and anterior segment of the eye using the SLSCAN-1, a new FD-OCT device integrated into a slit lamp. Methods Patients, seen in the outpatient clinic of the Academic Medical Center, were scanned with the SLSCAN-1, a newly developed OCT scanning device, integrated into a common slit lamp (figure 1). The OCT is a Fourier Domain OCT system (SLD light source, central wavelength 830 nm, bandwidth 30 nm, 1024 pixel CCD camera, scan speed 5k A-scans per second, 1024 A-scans per B-scan). The posterior segment scans have been captured using a standard indirect ophthalmic lens (Volk). A color fundus photography of the observed area is made at the same time (Topcon camera DC1, resolution = 3.24 Mp). Results For posterior segment imaging, the flexible optical arrangement of the slit lamp and the hand-held lens (Volk), allows the user to scan large areas of the retina (>45 degrees), depending on the pupil size of the patient. In all patients the macula and optic disk could be visualized without any difficulty. In the anterior segment mode, the SLSCAN-1 allows imaging of the cornea, anterior chamber, iris and parts of the lens. Conclusion The images made by the SLSCAN-, new slit lamp integrated FD-OCT, could be very useful to examine patients directly, both posterior and anterior, during regular slit lamp examinations. Commercial interest [source] Scanning beyond the limits of standard OCT: OCT scans of the peripheral retina and the anterior chamber angle with a slitlamp integtrated FD-OCT systemACTA OPHTHALMOLOGICA, Issue 2009M STEHOUWER Purpose Exploring the quality of OCT images of the peripheral retina and anterior chamber angle made through a 3-mirror contactlens and a new FD-OCT device integrated into a slit lamp. Methods Patients with peripheral lesions (n=10) and glaucoma (n=10), seen in the outpatient clinic of the Academic Medical Center, were scanned with a Fourier Domain OCT integrated into a common Topcon slitlamp (SLD light source, central wavelength 830 nm, bandwidth 30 nm, 1024 pixel CCD camera, scan speed 5k A-scans per second, up to 1024 A-scans per b-scan). For posterior segment scans a fast Z-tracking system in the reference arm compensates for the dynamic character (movements of patient, handheld lens, slitlamp) of the examination. Scans of peripheral lesions, and the anterior chamber angle were made with a 3-mirror lens, while simultaneously the lesions were observed with the slitlamp. Results Scans of the peripheral retina obtained with a 3-mirror lens with the FD-OCT integrated into the slitlamp were of reasonably good quality and lesions, like peripheral laser scars, could be clearly identified. Compared to stand alone OCT systems, the integrated OCT system reached more peripheral lesions. The anterior chamber angle scanned through a 3-mirror lens enabled scans of the angle structures. Conclusion It is possible to scan the peripheral retina and anterior chamber angle through a 3-mirror contact lens with the slitlamp with integrated OCT. These scans could be of clinical interest in patients with pathology in the peripheral retina pathology or the anterior chamber angle. [source] Optical Coherence Tomography: A Noninvasive Method to Assess Wound ReepithelializationACADEMIC EMERGENCY MEDICINE, Issue 5 2007Adam J. Singer MD BackgroundAccurate assessment of wound healing may require invasive tissue biopsies, limiting its clinical usefulness in humans. Optical coherence tomography (OCT) is a novel, high-resolution method using light reflection to obtain noninvasive cross sectional imaging of biological tissues. ObjectivesTo evaluate the utility of OCT for assessing wound reepithelialization in a porcine model. MethodsThe authors conducted an animal study with two domestic pigs. Excisional cutaneous wounds were created over the ventral surface of the animals using an electric dermatome set at a depth of 600 ,m. The wounds were excised two or three days later and precisely marked to guide initial OCT and subsequent tissue slicing and microscopy. Comparing hematoxylin and eosin,stained histologic sections and the corresponding OCT images from each tissue sample permitted identification of the correlative micromorphology. Scatter and Bland,Altman plots were used to present the data. The primary measure of agreement was the standard deviation of the pairwise differences in percent reepithelialization between OCT and histology together with a 95% confidence interval. ResultsIn normal skin, the epidermis was characterized by a thin, bright layer indicating a high degree of light scattering on OCT. The dermis below was characterized by a thicker, darker area indicating less scattering of light. All fresh excisional wounds lacked an outer bright layer of epidermis immediately after injury. At days 2 and 3, the wounds were partially reepithelialized. A new bright layer with intense light scattering was present on OCT corresponding to the neoepidermis on hematoxylin and eosin,stained sections. The correlation between percent reepithelialization measured with OCT and histology was 0.66 (p < 0.001), and the standard deviation of the differences was 11.0% (95% confidence interval = 8.4% to 16.1%). ConclusionsOCT accurately detects the presence or absence of the epidermal layer of skin, allowing noninvasive tracking of wound reepithelialization. [source] | ||||||||||