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Coherence Tomography (coherence + tomography)
Kinds of Coherence Tomography Terms modified by Coherence Tomography Selected AbstractsUSING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF CHINESE GLAZESARCHAEOMETRY, Issue 5 2009M.-L. YANG Optical coherence tomography (OCT), a new method for ceramics research, is a nondestructive, three-dimensional tomography system, which provides subsurface morphology visualization of samples based on the refractive index or dielectric constant differences in the target specimen. In this study, seven shards from different Chinese kilns of Song and Yuan dynasties (10,14th centuries) were scanned to visualize the subsurface morphology of their glazes. The images revealed unique phase assemblage modes in different samples. The results suggest OCT may be used to identify ceramics and provide information about their manufacturing technology. [source] Monitoring of glucose permeability in monkey skin in vivo using Optical Coherence TomographyJOURNAL OF BIOPHOTONICS, Issue 1-2 2010Mohamad G. Ghosn Abstract Topical trans-dermal delivery of drugs has proven to be a promising route for treatment of many dermatological diseases. The aim of this study is to monitor and quantify the permeability rate of glucose solutions in rhesus monkey skin noninvasively in vivo as a primate model for drug diffusion. A time-domain Optical Coherence Tomography (OCT) system was used to image the diffusion of glucose in the skin of anesthetized monkeys for which the permeability rate was calculated. From 5 experiments on 4 different monkeys, the permeability for glucose-20% was found to be (4.41 ± 0.28) 10,6 cm/sec. The results suggest that OCT might be utilized for the noninvasive study of molecular diffusion in the multilayered biological tissues in vivo. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Molecular Contrast Optical Coherence Tomography: A Review,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Changhuei Yang ABSTRACT This article reviews the current state of research on the use of molecular contrast agents in optical coherence tomography (OCT) imaging techniques. After a brief discussion of the basic principle of OCT and the importance of incorporating molecular contrast agent usage into this imaging modality, we shall present an overview of the different molecular contrast OCT (MCOCT) methods that have been developed thus far. We will then discuss several important practical issues that define the possible range of contrast agent choice, the design criteria for engineered molecular contrast agent and the implementability of a given MCOCT method for clinical or biological applications. We will conclude by outlining a few areas of pursuit that deserve a greater degree of research and development. [source] 1333: OCT: from single use to combined use in macular degenerationACTA OPHTHALMOLOGICA, Issue 2010C CREUZOT Purpose Optical Coherence Tomography (OCT) plays a key role in the diagnosis and the treatment of Age Macular Degeneration (AMD). Authors will present the different signs observed in OCT in exudative AMD. Methods Authors will present clinical cases to illustrate the place of the OCT in AMD diagnosis. OCT has progressively replaced the first-line tool played by angiography especially for the following of the patient once the treatment initiated. The different schemas currently proposed emphasize the role of the OCT combined with visual acuity measurement and fundus examination. Results However, the role of fluorescein and indocyanin green angiography remained essential especially to precise the clinical form before treatment. The combination of OCT and angiography remained a "key association" especially when there is some discrepancy between results or in case of treatment failure to consider another option. It is also the only opportunity for us to understand better the prognosis of these cases under treatment. Conclusion OCT has dramatically changed the supervision of exudative AMD especially during treatment. However, the combination with fluorescein and indocyanin angiograms is highly recommended not only for initial diagnosis but also in difficult cases during follow-up. [source] 4121: Combined OCT retinal nerve fibre layer analysis and VEP in neuro-ophthalmic diseaseACTA OPHTHALMOLOGICA, Issue 2010P GOOD Purpose Ocular Coherence Tomography (OCT) has become a valuable tool in assessing retinal nerve fibre layer thickness (RNFL) in Patients with optic nerve disease. This study is designed to compare RNFL thickness n with Visual Evoked Cortical Potentials (VECP)in patients with known optic nerve disease and comparing these to a group of patients with primary open angle glaucoma (POAG). Methods Twenty Patients (37 eyes) with clinically determined optic nerve disease underwent pattern reversal VECP and also OCT using a Spectralis OCT system. Assessment of global and segmental RNFL was made. Six Patients were diagnosed as Dominant Optic atrophy, 3 with Lebers Optic Neuropathy (LHON), 6 with Nutritional amblyopia, 3 with Anterior Ischaemic Optic Neuropathy (AION), and 2 with Demyelinating disease. These Patients were also compared to a group of 10 patients (20 eyes) with Primary Open Angle Glaucoma POAG. Results Pattern reversal VECP were abnormal in 32/37 eyes (86%): 26/32 (81%) of these being of reduced amplitude, and 20/32 (62%) being delayed. Amongst the patients with POAG only 4/20 eyes (20%) had abnormal VECP, and none were delayed. Thinning of the RNFL occurred in 36/37 eyes (97%) with optic nerve disease; 24 (65%) had global thinning, and the remainder segmental thinning only. All of the eyes with POAG had RNFL thinning but only 6/20 eyes (30%) had global thinning. Bipolar cell thinning of the central retina was noted in 6 eyes with optic nerve disease. Conclusion OCT is a valuable tool in the assessment of patients with optic nerve disease. Thinning of the RNFL was a more consistent finding than delay of the VECP in optic nerve disease, and a combination of VECP and OCT is helpful in the differential diagnosis of low tension glaucoma and optic nerve disease. [source] 2145: Descemet´s membrane detachment 16 years after PK and 10 months after phacoACTA OPHTHALMOLOGICA, Issue 2010JO FERNANDEZ MENDY Purpose The purpose of this paper is to present an unusual case of DMD and analyze this complication Methods A 57-year-old woman, who had bilateral keratoconus, underwent three penetrating keratoplasties (PK) on her RE in 1981, 1993 and 1995 resulting in ptisis bulbi. In her LE she underwent two PK (1981, 1994) follow by arcuate incisions (1995) and an uneventful phacoemulsification in 2007. 10 months after cataract surgery, she begun with blurred vision, the BCVA was 20/400 and was seen by 3 ophthalmologists who made the diagnosis of endothelial failure and suggested a new PK or a DSAEK. We performed an Optical Coherence Tomography, diagnosing a complete Descemet´s membrane detachment (DMD). An intracameral gas injection of C3F8 at 16% was performed in the operating room, and the patient was instructed to maintain a supine position. After 24 hours VA improved to 20/80 and after 72 hours 20/30 UCVA. A small bubble was present in the anterior chamber for more than 3 weeks. One month later she achieved 20/20 with Contact Lens. During the first year after reattachment it was necessary to change the CL due to an increasing with the rule astigmatism from 3D to 5D. Results Two years after gas injection BSVA is 20/25 because she is no longer using CL, Descemet´s membrane still remains well attached, even thought we realized that there was a trend to steepen the vertical meridian due to the widening of a nasal arcuate incision, that we think was the origin of the DMD. Conclusion DMD is a rare complication of Phacoemulsification, seen immediately after the surgery. So far there has not reported any complete DMD after phaco after PK. We think that it is mandatory to perform a corneal OCT in all cases of PK and stromal edema; it could probably be a DMD. [source] Telangiectasia evaluated with adaptive optics and HR-OCTACTA OPHTHALMOLOGICA, Issue 2009K ATMANI Purpose Type 2 Macular Telangiectasia is a progressive disease starting in the fifth to seventh decade and characterized by a progressive damage of the neurosensory retina.. The purpose of this study is to compare the images obtained using two non-invasive techniques, High-Resolution Optical Coherence Tomography (HR-OCT) and Adaptive Optics (AO), in Type 2 Macular Telangiectasia. Methods Nine eyes of 5 patients affected by Type 2 Macular Telangiectasia underwent examination including visual acuity measurement with ETDRS (Early Treatment of Diabetic Retinopathy Study) chart, color photographs, monochromatic photographs, Spectral-Domain Optical Coherence Tomography with Heidelberg SpectralisÔ OCT and Adaptive Optics assessment with Imagine EyesÔ System. The neurosensory retina and the photoreceptor layer were analyzed using both HR-OCT and AO imaging. Results The disruptions of the photoreceptor layer on HR-OCT correspond to a cellular loss on Adaptive Optics Imaging. On the other hand, Adaptive optics Imaging allows the measurement of cellular density in areas which have a normal aspect on HR-OCT. Conclusion The diagnosis of Macular Telangiecctasia is based on biomicroscopy and fluorescein angiography. Adaptive Optics Imaging is helpful to analyze the retinal damages, especially the cone abnormalities. This technique will certainly allow a better understanding of this rare disease. Author Disclosure Information: K. Atmani, None; N. Leveziel, None G. Soubrane, None. [source] Chorioretinal anastomosis in adaptive optic and high definition spectral domain optical coherence tomographyACTA OPHTHALMOLOGICA, Issue 2009C MAILLON Purpose To assess morphologic variations in the outer and inner retinal layers in eyes with chorioretinal anatomosis using high definition Spectral Domain Optical Coherence Tomography (Spectralis HRA OCT, Heidelberg Engineering, Heidelberg, Germany) and to compare these scans with images acquired by Adaptive Optics (AO). Methods This was a prospective observational case series including 50 patients. SD-OCT scans were obtained with combined confocal scanning laser ophthalmoscope (cSLO) and SD-OCT for simultaneous tomographic and topographic in vivo imaging. Patients underwent fluorescein and ICG- angiography and Adaptive Optics assessment with Imagine EyesÔ System. The neurosensory retina and the photoreceptor layer were analyzed using both HR-OCT and AO imaging. Results Combining of the adaptive optics with SD-OCT may give us further information of the early stage development of chorioretinal anastomosis. [source] Preterm and at term children: morphological and functional analysis of optic nerve and visual pathway with OCT, HRT and pVEPACTA OPHTHALMOLOGICA, Issue 2009R ANGELI Purpose To compare optic nerve morphology and visual function in 14 preterm children(mean gestational age:33,38) with normal cerebral ultrasound at birth and 15 at term children (mean gestational age:39,67). Methods Mean preterm age was 7,6 years, mean at term was 9,1 years. Children underwent to complete functional and morphological evaluation of Optic Nerve Head (ONH) with Heidelberg Retinal Tomography and Optical Coherence Tomography. The same children were evaluated at birth and at the time of morphological examinations by mean of transient and steady state pVEP. Results Mean visual acuity was 9,85 in the preterm, 10 in the at term children. HRT in preterm and at term children at term(n=28) preterm(n=25) P value mean sd mean sd Disc Area 2,5 0,7 2,34 0,68 0,38 Cup Area 0,50 0,44 0,58 0,47 0,51 Rim Area 2 0,45 1,76 0,37 0,047 C/D Area Ratio 0,18 0,12 0,22 0,14 0,23 C/D Linear Ratio 0,4 0,15 0,45 0,16 0,30 Mean RNFL Thick 0,2 0,07 0,24 0,2 0,26 Tab.1 A statistically significant reduction was found in preterm children as regard rim area (p=0,047,tab 1) at HRT and superior RNFL thickness (p=0,01), temporal and inferior inner macular thickness (p=0,03) at OCT. Differences in the pVep latencies were found at 3 and 8 months after birth, but not at the time of morphological examination. Steady State pVEP amplitudes differences were not statistically significant. Conclusion Morphologic optic disk and macula differences between term and preterm children seems not functionally affect the visual pathway. [source] Contribution of OCT to evaluate macular disease in JIA associated uveitisACTA OPHTHALMOLOGICA, Issue 2008B BODAGHI Purpose To examine the frequency and characteristics of macular lesions observed in Juvenile Idiopathic Arthritis (JIA) uveitis, using Optical Coherence Tomography (OCT). Methods In this cross-sectional study, 38 consecutive patients were recruited from a tertiary referral center in uveitis. All eyes with JIA uveitis underwent complete ophthalmic examination including OCT 3. Exclusion criterion was the inability to obtain OCT scans. Flare and visual acuity were also analyzed by using linear regression. Results We analyzed foveal thickness (FT) and central foveal thickness (CFT) using the software mapping, to describe macular lesions in 61 eyes. Maculopathy was observed in 51 eyes (84%), compared to 12% in the literature (P<0.0001) and comprised four types: perifoveolar thickening in 45 eyes (74%), macular edema in 29 eyes (48%), foveal detachment in 11 eyes (18%), and atrophic changes in 6 eyes (10%). Only 4 eyes did not demonstrate any lesion. Conclusion Among children with JIA-uveitis, macular involvement is frequent, and characterized by perifoveolar thickening and serous retinal detachment. OCT is a non-invasive instrument. It may easily show this maculopathy, which could impair visual function, and conditioned a therapeutic intensification. [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] 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] Diagnosis of Nonmelanoma Skin Cancer/Keratinocyte Carcinoma: A Review of Diagnostic Accuracy of Nonmelanoma Skin Cancer Diagnostic Tests and TechnologiesDERMATOLOGIC SURGERY, Issue 10 2007METTE MOGENSEN MD BACKGROUND Nonmelanoma skin cancer (NMSC) is the most prevalent cancer in the light-skinned population. Noninvasive treatment is increasingly used for NMSC patients with superficial lesions, making the development of noninvasive diagnostic technologies highly relevant. OBJECTIVE The scope of this review is to present data on the current state-of-the-art diagnostic methods for keratinocyte carcinoma: basal cell carcinoma, squamous cell carcinoma, and actinic keratosis. METHODS AND MATERIALS MEDLINE, BIOSIS, and EMBASE searches on NMSC and physical and clinical examination, biopsy, molecular marker, ultrasonography, Doppler, optical coherence tomography, dermoscopy, spectroscopy, fluorescence imaging, confocal microscopy, positron emission tomography, computed tomography, magnetic resonance imaging, terahertz imaging, electrical impedance and sensitivity, specificity, and diagnostic accuracy. RESULTS State-of-the-art diagnostic research has been limited in this field, but encouraging results from the reviewed diagnostic trials have suggested a high diagnostic accuracy for many of the technologies. Most of the studies, however, were pilot or small studies and the results would need to be validated in larger trials. CONCLUSIONS Some of these new imaging technologies have the capability of providing new, three-dimensional in vivo, in situ understanding of NMSC development over time. Some of the new technologies described here have the potential to make it from the bench to the clinic. [source] Photodiagnostic techniques for the endoscopic detection of premalignant gastrointestinal lesionsDIGESTIVE ENDOSCOPY, Issue 3 2003Ralph S. DaCosta Considerable attention is given to the clinical diagnosis of gastrointestinal (GI) malignancies as they remain the second leading cause of cancer-associated deaths in developed countries. Detection and intervention at an early stage of preneoplastic development significantly improve patient survival. High-risk assessment of asymptomatic patients is currently performed by strict endoscopic surveillance biopsy protocols aimed at early detection of dysplasia and malignancy. However, poor sensitivity associated with frequent surveillance programs incorporating conventional screening tools, such as white light endoscopy and multiple random biopsy, is a significant limitation. Recent advances in biomedical optics are illuminating new ways to detect premalignant lesions of the GI tract with endoscopy. The present review presents a summary report on the newest developments in modern GI endoscopy, which are based on novel optical endoscopic techniques: fluorescence endoscopic imaging and spectroscopy, Raman spectroscopy, light scattering spectroscopy, optical coherence tomography, chromoendoscopy, confocal fluorescence endoscopy and immunofluorescence endoscopy. Relying on the interaction of light with tissue, these ,state-of-the-art' techniques potentially offer an improved strategy for diagnosis of early mucosal lesions by facilitating targeted excisional biopsies. Furthermore, the prospects of real-time ,optical biopsy' and improved staging of lesions may significantly enhance the endoscopist's ability to detect subtle preneoplastic mucosal changes and lead to curative endoscopic ablation of these lesions. Such advancements within this specialty will be rewarded in the long term with improved patient survival and quality of life. [source] Barrett's esophagus: current and future role of endosonography and optical coherence tomographyDISEASES OF THE ESOPHAGUS, Issue 2 2004S. A. Faruqi SUMMARY., This paper reviews the role of endosonography and optical coherence tomography (OCT) for imaging of Barrett's esophagus (BE). The routine use of endoscopic ultrasound (EUS) to screen patients with BE is neither justified nor cost effective. EUS does appear to have a role in patients who have BE and high-grade dysplasia or intramucosal carcinoma, in whom a non-operative therapy is being contemplated. For patients with a diagnosis of esophageal cancer with or without BE, EUS is superior to computed tomography or magnetic resonance imaging for assessing esophageal wall penetration and for detecting regional lymph node involvement. In its current state, OCT is not yet ready for application in clinical practice. However, given its superior resolution compared with other modalities such as EUS, OCT has great potential as a powerful adjunct to standard endoscopy in surveillance of BE and may enhance the ability of endoscopists to detect high-grade dysplasia at an early stage. With further technical refinement, this technique may become a mainstay in the surveillance of BE and other premalignant conditions of the gastrointestinal tract. [source] Clinical value of optical coherence tomography in laryngologyHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 12 2008Marcel Kraft MD Abstract Background. Optical coherence tomography (OCT) is a new, noninvasive imaging technology for the evaluation of superficial lesions. The objective of this study is to evaluate microlaryngoscopy in combination with OCT compared with microlaryngoscopy alone (ie, without OCT) in supplying a specific diagnosis, predicting invasive tumor growth and epithelial dysplasia in the larynx. Methods. This was a prospective study including 217 laryngeal lesions in a total of 193 patients undergoing surgery. Intraoperative suspicion diagnosis gained by microlaryngoscopy with and without OCT was compared with conventional histopathology after excisional biopsy. Results. Microlaryngoscopy with OCT supplied a specific diagnosis in 89% of cases, but in only 80% of cases with microlaryngoscopy alone. In particular, our results in malignant and benign pathologies were correct in 93% each, and the exact grade of dysplasia could be predicted in 71% of precancerous lesions. Microlaryngoscopy with OCT presented a higher sensitivity than microlaryngoscopy alone in predicting invasive tumor growth (93% vs 87%) and epithelial dysplasia (78% vs 66%), but the specificity and accuracy were comparable in both methods. Conclusions. OCT is a simple, rapid, and reliable aid in the diagnostic investigation and intraoperative monitoring of laryngeal disease. © 2008 Wiley Periodicals, Inc. Head Neck, 2008 [source] Gold Nanocages for Biomedical Applications,ADVANCED MATERIALS, Issue 20 2007E. Skrabalak Abstract Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the synthesis and use of Au nanocages for such biomedical applications. Gold nanocages represent a novel class of nanostructures, which can be prepared via a remarkably simple route based on the galvanic replacement reaction between Ag nanocubes and HAuCl4. The Au nanocages have a tunable surface plasmon resonance peak that extends into the near-infrared, where the optical attenuation caused by blood and soft tissue is essentially negligible. They are also biocompatible and present a well-established surface for easy functionalization. We have tailored the scattering and absorption cross-sections of Au nanocages for use in optical coherence tomography and photothermal treatment, respectively. Our preliminary studies show greatly improved spectroscopic image contrast for tissue phantoms containing Au nanocages. Our most recent results also demonstrate the photothermal destruction of breast cancer cells in vitro by using immuno-targeted Au nanocages as an effective photo-thermal transducer. These experiments suggest that Au nanocages may be a new class of nanometer-sized agents for cancer diagnosis and therapy. [source] pH-induced alterations in stratum corneum propertiesINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2003K. P. Ananthapadmanabhan Synopsis Skin-cleansing compositions based on alkyl carboxylates (soaps) have a higher irritation potential than those based on syndet surfactants such as alkyl isethionates or alkyl ether sulphates. Contributing factors include inherent differences in the irritation potential of soaps and syndet surfactants, pH-induced changes in surfactant solution chemistry, and the direct effects of pH on the physical properties of the stratum corneum (SC). Past work has not directly addressed the effect of solution pH on the SC itself and its potential role in cleanser-induced skin irritation. In the current work, alterations to SC properties induced by buffered pH solutions and two strongly ionizable surfactants, sodium dodecyl sulphate and sodium lauryl ether sulphate, at different pH values are measured. By utilizing optical coherence tomography (OCT) and infrared (IR) spectroscopy we have directly measured physical changes in SC proteins and lipids. Our results indicate that SC swelling, which reflects alterations to SC structural proteins, is increased significantly at pH 10, compared to pH 4 and 6.5. The transition temperature (Tm) of SC lipids is found to increase at pH 10, compared to pH 4 and 6.5, suggesting a more rigid SC lipid matrix. Surfactants cause a further increase in swelling and lipid rigidity. Some aspects of what these results mean for SC physical properties as well as their implications to potential mechanisms of surfactant-induced skin irritation are discussed. Résumé Les compositions nettoyantes pour la peau à base d'alkyl carboxylates (savons) ont un potentiel irritant supérieur à celles à base de syndet tensioactifs tels que les alkyl isothionates ou les alkyl ether sulfates. Les facteurs en cause comprennent les différences de potentiel irritant inhérentes aux savons et aux syndet tensioactifs, les modifications de la chimie de la solution de tensioactif dues aux pH, et les effets directs du pH sur les propriétés physiques de la couche cornée (CC). Les travaux antérieurs n'ont pas traité directement l'effet du pH de la solution sur la couche cornée elle-même et son rôle potentiel dans l'irritation de la peau due à la solution nettoyante. Dans la présente étude on a mesuré les altérations des propriétés de la CC causées par des solutions à pH tamponné et deux tensioactifs fortement ionisables, le dodecyl sulfate de sodium et le lauryl ether sulfate de sodium, à différentes valeurs de pH. En utilisant la tomographie optique (OCT) et la spectroscopie à infrarouge (IR) on a mesuré directement les modifications physiques des protéines et des lipides de la CC. Nos résultats montrent que le gonflement de la CC, qui traduit des altérations des protéines structurales de la CC, augmente significativement à pH 10, par comparaison au pH 4 et 6.5. On observe que la température de transition (Tm) des lipides de la CC augmente à pH 10, par comparaison au pH 4 et 6.5, suggérant une matrice lipidique de la CC plus rigide. Les tensioactifs provoquent une augmentation plus importante du gonflement et de la rigidité lipidique. On aborde certains aspects de la signification de ces résultats vis-à-vis des propriétés physiques de la couche cornée ainsi que leurs conséquences sur les mécanismes potentiels de l'irritation de la peau causée par les tensioactifs. [source] Cover Picture: J. Biophoton.JOURNAL OF BIOPHOTONICS, Issue 11 200911/200 Structural and functional imaging of engineered tissues using optical coherence tomography and multi-modal optical imaging techniques: Visualizing and elucidating the complex dynamic processes that occur in developing engineered tissues requires innovative integrated imaging solutions that bridge the divide between imaging structure and function. Images shown represent a variety of optical imaging techniques and methods, several of which are highlighted in the review article by Liang, Graf, and Boppart (pp. 643,655, in this issue) (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Imaging engineered tissues using structural and functional optical coherence tomographyJOURNAL OF BIOPHOTONICS, Issue 11 2009Xing Liang Abstract As the field of tissue engineering evolves, there will be an increasingly important need to visualize and track the complex dynamic changes that occur within three-dimensional constructs. Optical coherence tomography (OCT), as an emerging imaging technology applied to biological materials, offers a number of significant advantages to visualize these changes. Structural OCT has been used to investigate the longitudinal development of engineered tissues and cell dynamics such as migration, proliferation, detachment, and cell-material interactions. Optical techniques that image functional parameters or integrate multiple imaging modalities to provide complementary contrast mechanisms have been developed, such as the integration of optical coherence microscopy with multiphoton microscopy to image structural and functional information from cells in engineered tissue, optical coherence elastography to generate images or maps of strain to reflect the spatially-dependent biomechanical properties, and spectroscopic OCT to differentiate different cell types. From these results, OCT demonstrates great promise for imaging and visualizing engineered tissues, and the complex cellular dynamics that directly affect their practical and clinical use. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Recent developments in Fourier Domain Mode Locked lasers for optical coherence tomography: Imaging at 1310 nm vs.JOURNAL OF BIOPHOTONICS, Issue 6-7 20091550 nm wavelength Abstract We report on recent progress in Fourier domain mode-locking (FDML) technology. The paper focuses on developments beyond pushing the speed of these laser sources. After an overview of improvements to FDML over the last three years, a brief analysis of OCT imaging using FDML lasers with different wavelengths is presented. For the first time, high speed, high quality FDML imaging at 1550 nm is presented and compared to a system at 1310 nm. The imaging results of human skin for both wavelengths are compared and analyzed. Sample arm optics, power on the sample, heterodyne gain, detection bandwidth, colour cut levels and sample location have been identical to identify the influence of difference in scattering and water absorption. The imaging performance at 1310 nm in human skin is only slightly better and the results suggest that water absorption only marginally affects the penetration depth in human skin at 1550 nm. For several applications this wavelength may be preferred. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [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] OCT imaging of skin cancer and other dermatological diseasesJOURNAL OF BIOPHOTONICS, Issue 6-7 2009Mette Mogensen Abstract Optical coherence tomography (OCT) provides clinicians and researchers with micrometer-resolution, in vivo, cross-sectional images of human skin up to several millimeter depth. This review of OCT imaging applied within dermatology covers the application of OCT to normal skin, and reports on a large number of applications in the fields of non-melanoma skin cancer, malignant melanomas, psoriasis and dermatitis, infestations, bullous skin diseases, tattoos, nails, haemangiomas, and other skin diseases. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Bisphosphonate-Associated Osteonecrosis of the Jaw: Report of a Task Force of the American Society for Bone and Mineral Research,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2007Sundeep Khosla (Chair) Abstract ONJ has been increasingly suspected to be a potential complication of bisphosphonate therapy in recent years. Thus, the ASBMR leadership appointed a multidisciplinary task force to address key questions related to case definition, epidemiology, risk factors, diagnostic imaging, clinical management, and future areas for research related to the disorder. This report summarizes the findings and recommendations of the task force. Introduction: The increasing recognition that use of bisphosphonates may be associated with osteonecrosis of the jaw (ONJ) led the leadership of the American Society for Bone and Mineral Research (ASBMR) to appoint a task force to address a number of key questions related to this disorder. Materials and Methods: A multidisciplinary expert group reviewed all pertinent published data on bisphosphonate-associated ONJ. Food and Drug Administration drug adverse event reports were also reviewed. Results and Conclusions: A case definition was developed so that subsequent studies could report on the same condition. The task force defined ONJ as the presence of exposed bone in the maxillofacial region that did not heal within 8 wk after identification by a health care provider. Based on review of both published and unpublished data, the risk of ONJ associated with oral bisphosphonate therapy for osteoporosis seems to be low, estimated between 1 in 10,000 and <1 in 100,000 patient-treatment years. However, the task force recognized that information on incidence of ONJ is rapidly evolving and that the true incidence may be higher. The risk of ONJ in patients with cancer treated with high doses of intravenous bisphosphonates is clearly higher, in the range of 1,10 per 100 patients (depending on duration of therapy). In the future, improved diagnostic imaging modalities, such as optical coherence tomography or MRI combined with contrast agents and the manipulation of image planes, may identify patients at preclinical or early stages of the disease. Management is largely supportive. A research agenda aimed at filling the considerable gaps in knowledge regarding this disorder was also outlined. [source] Use of optical coherence tomography for assessment of dental caries: quantitative procedureJOURNAL OF ORAL REHABILITATION, Issue 12 2001B. T. Amaechi A method for quantitative assessment of dental caries using optical coherence tomography (OCT) was demonstrated. Development of caries lesions in 15 bovine teeth, by demineralization in acidic buffer solution, was quantitatively assessed daily for 3 days, using OCT. An OCT system which can collect A-scans (depth versus reflectivity curve), B-scans (longitudinal images) and C-scans (transverse images at constant depth) was used. While the B- and C-scans qualitatively described the lesion detected, the A-scan which showed the depth (mm) resolved reflectivity (dB) of the tooth tissue was used for the quantitative analysis. After a simple normalization procedure to determine the actual depth the light travelled into the tooth tissue, the area (R) under the A-scan was quantified as a measure of the degree of reflectivity of the tissue. The result showed that R (dB mm) decreased with increasing demineralization time. The percentage reflectivity loss (R%) in demineralized tissue, which related to the amount of mineral loss, was also calculated, and it was observed that R% increased with increasing demineralization time. It was concluded that with the above procedure, OCT could quantitatively monitor the mineral changes in a caries lesion on a longitudinal basis. [source] High-resolution imaging of progressive articular cartilage degenerationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006Samuel B. Adams Jr Abstract The objective of this study was to develop and verify a new technique for monitoring the progression of osteoarthritis (OA) by combining a rat model with the imaging modality optical coherence tomography (OCT). Time-sequential, in vivo, OCT imaging was performed on the left femoral condyles of 12 Wistar rats following sodium,iodoacetic acid-induced OA progression. The right femoral condyles (untreated) were also imaged and served as controls. Imaging was performed on days 0, 10, 20, 30, and 60 with an OCT system capable of acquiring images at four frames per second and an axial resolution of 5 µm. Progressive changes were analyzed using an OA scoring system. OCT successfully identified progressive cartilage degeneration as well as alteration of the cartilage/bone interface. Significant changes to both of these structures were observed in the sodium,iodoacetic acid-injected condyles. Structural changes detected with OCT were confirmed histologically. OCT in combination with a well-known model used in arthritis research represents a powerful tool for following degenerative joint disease progression in a given animal by detecting changes to the cartilage/bone interface and articular cartilage. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Imaging pharmaceutical tablets with optical coherence tomographyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2010Jakob M.A. Mauritz Abstract Optical coherence tomography (OCT) is a recently developed optical technique that produces depth profiles of three-dimensional objects. It is a nondestructive interferometric method responding to refractive index variation in the sample under study and can reach a penetration depth of a few millimetres. OCT employs near-infrared (NIR) light and therefore provides a link between NIR spectroscopy and Terahertz (THz) measurements that are often used to characterise tablets. In this article we assess the potential of OCT as a reliable and practical tool in the analysis of pharmaceutical tablets and coatings. A variety of tablets were tested with different shapes, formulations and coatings. We consider the origins of contrast in the obtained images and demonstrate that it correlates strongly with the expected tablet structure. The influence of absorption and scattering are considered for the wavelength ranges used. The results show that OCT is a promising diagnostic tool with an important role to play in the tablet and coating technologies. The high measurement speed of OCT and its relative ease of implementation make it also an attractive candidate technology for in-line quality control during manufacturing. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:385,391, 2010 [source] Plant photonics: application of optical coherence tomography to monitor defects and rots in onionLASER PHYSICS LETTERS, Issue 4 2010I.V. Meglinski Abstract The incidence of physiological and/or pathological defects in many fresh produce types is still unacceptably high and accounts for a large proportion of waste. With increasing interest in food security their remains strong demand in developing reliable and cost effective technologies for non-destructive screening of internal defects and rots, these being deemed unacceptable by consumers. It is well recognized that the internal defects and structure of turbid scattering media can be effectively visualized by using optical coherence tomography (OCT). In the present study, the high spatial resolution and advantages of OCT have been demonstrated for imaging the skins and outer laminae (concentric tissue layers) of intact whole onion bulbs with a view to non-invasively visualizing potential incidence/severity of internal defects. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [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] Magneto-motive detection of tissue-based macrophages by differential phase optical coherence tomographyLASERS IN SURGERY AND MEDICINE, Issue 3 2007Junghwan Oh PhD Abstract Background and Objectives A novel method to detect tissue-based macrophages using a combination of superparamagnetic iron oxide (SPIO) nanoparticles and differential phase optical coherence tomography (DP-OCT) with an external oscillating magnetic field is reported. Study Design/Material and Methods Magnetic force acting on iron-laden tissue-based macrophages was varied by applying a sinusoidal current to a solenoid containing a conical iron core that substantially focused and increased magnetic flux density. Results Nanoparticle motion was detected with DP-OCT, which can detect tissue movement with nanometer resolution. Frequency response of iron-laden tissue movement was twice the modulation frequency since the magnetic force is proportional to the product of magnetic flux density and gradient. Conclusions Results of our experiments indicate that DP-OCT can be used to identify tissue-based macrophage when excited by an external focused oscillating magnetic field. Lasers Surg. Med. 39:266,272, 2007. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||