1. Articles from Claude Boccara

    1-24 of 33 1 2 »
    1. Dynamic full-field optical coherence tomography as complementary tool in fungal diagnostics

      Dynamic full-field optical coherence tomography as complementary tool in fungal diagnostics

      Histopathology and microscopic examination of infected tissue are the gold standards to prove the diagnosis of invasive fungal infection (IFI). Yet, they suffer from essential limitations that hamper rapid diagnosis and require the future development of new imaging tools dedicated to fungal diagnostics. To this end, the present work introduces the first use of dynamic full-field optical coherence tomography (D-FF-OCT) for the visualization of microscopic filamentous fungi. Data collected from the observation of three different fungal species (Nannizzia gypsea, Aspergillus fumigatus and Rhizopus arrhizus) confirm the ability of D-FF-OCT to visualize not only the main structures of all selected fungal ...

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    2. Dynamic full-field optical coherence tomography allows live imaging of retinal pigment epithelium stress model

      Dynamic full-field optical coherence tomography allows live imaging of retinal pigment epithelium stress model

      Retinal degenerative diseases lead to the blindness of millions of people around the world. In case of age-related macular degeneration (AMD), the atrophy of retinal pigment epithelium (RPE) precedes neural dystrophy. But as crucial as understanding both healthy and pathological RPE cell physiology is for those diseases, no current technique allows subcellular in vivo or in vitro live observation of this critical cell layer. To fill this gap, we propose dynamic full-field OCT (D-FFOCT) as a candidate for live observation of in vitro RPE phenotype. In this way, we monitored primary porcine and human stem cell-derived RPE cells in stress ...

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    3. Quantitative evaluation of the dynamic activity of HeLa cells in different viability states using dynamic full-field optical coherence microscopy

      Quantitative evaluation of the dynamic activity of HeLa cells in different viability states using dynamic full-field optical coherence microscopy

      Dynamic full-field optical coherence microscopy (DFFOCM) was used to characterize the intracellular dynamic activities and cytoskeleton of HeLa cells in different viability states. HeLa cell samples were continuously monitored for 24 hours and compared with histological examination to confirm the cell viability states. The averaged mean frequency and magnitude observed in healthy cells were 4.79±0.5 Hz and 2.44±1.06, respectively. In dead cells, the averaged mean frequency was shifted to 8.57±0.71 Hz, whereas the magnitude was significantly decreased to 0.53±0.25. This cell dynamic activity analysis using DFFOCM is expected ...

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    4. Non invasive live imaging of a novel RPE stress model with Dynamic Full-Field OCT

      Non invasive live imaging of a novel RPE stress model with Dynamic Full-Field OCT

      Retinal degenerative diseases lead to the blindness of millions of people around the world. In case of age-related macular degeneration (AMD), the atrophy of retinal pigment epithelium (RPE) precedes neural dystrophy. But as crucial as understanding both healthy and pathological RPE cell physiology is for those diseases, no current technique allows subcellular in vivo or in vitro live observation of this critical cell layer. To fill this gap, we propose dynamic full-field OCT (D-FFOCT) as a candidate for live observation of in vitro RPE phenotype. In this way, we monitored primary porcine and human stem cell-derived RPE cells in stress ...

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    5. Adaptive-glasses time-domain FFOCT for wide-field high-resolution retinal imaging with increased SNR

      Adaptive-glasses time-domain FFOCT for wide-field high-resolution retinal imaging with increased SNR

      The highest three-dimensional (3D) resolution possible in in vivo retinal imaging is achieved by combining optical coherence tomography (OCT) and adaptive optics. However, this combination brings important limitations, such as small field-of-view and complex, cumbersome systems, preventing so far the translation of this technology from the research lab to clinics. In this Letter, we mitigate these limitations by combining our compact time-domain full-field OCT (FFOCT) with a multi-actuator adaptive lens positioned just in front of the eye, in a technique we call the adaptive-glasses wavefront sensorless approach. Through this approach, we demonstrate that ocular aberrations can be corrected, increasing the ...

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      Mentions: ESPCI ParisTech
    6. Coherence gate shaping for wide field high-resolution in vivo retinal imaging with full-field OCT

      Coherence gate shaping for wide field high-resolution in vivo retinal imaging with full-field OCT

      Allying high-resolution with a large field-of-view (FOV) is of great importance in the fields of biology and medicine, but it is particularly challenging when imaging non-flat living samples such as the human retina. Indeed, high-resolution is normally achieved with adaptive optics (AO) and scanning methods, which considerably reduce the useful FOV and increase the system complexity. An alternative technique is time-domain full-field optical coherence tomography (FF-OCT), which has already shown its potential for in-vivo high-resolution retinal imaging. Here, we introduce coherence gate shaping for FF-OCT, to optically shape the coherence gate geometry to match the sample curvature, thus achieving a ...

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      Mentions: ESPCI ParisTech
    7. Dynamic full-field optical coherence tomography: 3D live-imaging of retinal organoids

      Dynamic full-field optical coherence tomography: 3D live-imaging of retinal organoids

      Optical coherence tomography offers astounding opportunities to image the complex structure of living tissue but lacks functional information. We present dynamic full-field optical coherence tomography as a technique to noninvasively image living human induced pluripotent stem cell-derived retinal organoids. Coloured images with an endogenous contrast linked to organelle motility are generated, with submicrometre spatial resolution and millisecond temporal resolution, creating a way to identify specific cell types in living tissue via their function. The comprehension of the human body and its mechanisms at the subcellular scale is still an open area of research. During the seventeenth century, the first examinations ...

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    8. Full-field optical coherence tomography: novel imaging technique for extemporaneous high-resolution analysis of mucosal architecture in human gut biopsies

      Full-field optical coherence tomography: novel imaging technique for extemporaneous high-resolution analysis of mucosal architecture in human gut biopsies

      Full-field optical coherence tomography (FFOCT) is an imaging technique of biological tissue based on tissue light reflectance analysis. We evaluated the feasibility of imaging fresh digestive mucosal biopsies after a quick mounting procedure (5 min) using two distinct modalities of FFOCT. In static FFOCT mode, we gained high-resolution images of general gut tissue-specific architecture, such as oesophageal papillae, gastric pits, duodenal villi and colonic crypts. In dynamic FFOCT mode, we imaged individual epithelial cells of the mucosal lining with a cellular or subcellular resolution and identified cellular components of the lamina propria. FFOCT represents a promising dye-free imaging tool for ...

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    9. Full-field optical coherence tomography for the diagnosis of giant cell arteritis

      Full-field optical coherence tomography for the diagnosis of giant cell arteritis

      Histopathological examination of temporal artery biopsy (TAB) remains the gold standard for the diagnosis of giant cell arteritis (GCA) but is associated with essential limitations that emphasize the need for an upgraded pathological process. This study pioneered the use of full-field optical coherence tomography (FF-OCT) for rapid and automated on-site pathological diagnosis of GCA. Sixteen TABs (12 negative and 4 positive for GCA) were selected according to major histopathological criteria of GCA following hematoxylin-eosin-saffron-staining for subsequent acquisition with FF-OCT to compare structural modifications of the artery cell wall and thickness of each tunica. Gabor filtering of FF-OCT images was then ...

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      Mentions: ESPCI ParisTech
    10. Curved-Full-Field OCT for high-resolution imaging of living human retina over a large field-of-view

      Curved-Full-Field OCT for high-resolution imaging of living human retina over a large field-of-view

      Allying high-resolution with a large field-of-view (FOV) is of great importance in the fields of biology and medicine [1, 2, 3], but particularly challenging when imaging non-flat living samples such as the human retina. Indeed, high-resolution is normally achieved with adaptive optics (AO) and scanning methods, which considerably reduce the useful FOV and increase the system complexity. An alternative technique is time-domain Full-Field Optical Coherence Tomography (FF-OCT) [4, 5], which has already shown its potential for in-vivo high-resolution retinal imaging [6]. Here, we introduce curved-field FF-OCT, capable of matching the coherence gate geometry to the sample curvature, thus achieving a ...

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      Mentions: ESPCI ParisTech
    11. High-resolution in-vivo human retinal imaging using full-field OCT with optical stabilization of axial motion

      High-resolution in-vivo human retinal imaging using full-field OCT with optical stabilization of axial motion

      Time-domain full-field OCT (FF-OCT) represents an imaging modality capable of recording high-speed en-face sections of a sample at a given depth. One of the biggest challenges to transfer this technique to image in-vivo human retina is the presence of continuous involuntary head and eye axial motion during image acquisition. In this paper, we demonstrate a solution to this problem by implementing an optical stabilization in an FF-OCT system. This was made possible by combining an FF-OCT system, an SD-OCT system, and a high-speed voice-coil translation stage. B-scans generated by the SD-OCT were used to measure the retina axial position and ...

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      Mentions: ESPCI ParisTech
    12. Dynamic full-field optical coherence tomography: 3D live-imaging of retinal organoids

      Dynamic full-field optical coherence tomography: 3D live-imaging of retinal organoids

      Optical coherence tomography offers astounding opportunities to image the complex structure of living tissue, but lacks functional information. We present dynamic full-field optical coherence tomography to image living human induced pluripotent stem cell-derived retinal organoids non-invasively. Colored images with an endogenous contrast linked to organelle motility are generated, with sub-micrometer spatial resolution and millisecond temporal resolution, opening an avenue to identify specific cell types in living tissue via their function.

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    13. Probing dynamic processes in the eye at multiple spatial and temporal scales with multimodal full field OCT

      Probing dynamic processes in the eye at multiple spatial and temporal scales with multimodal full field OCT

      We describe recent technological progress in multimodal en face full-field optical coherence tomography that has allowed detection of slow and fast dynamic processes in the eye. We show that by combining static, dynamic and fluorescence contrasts we can achieve label-free high-resolution imaging of the retina and anterior eye with temporal resolution from milliseconds to several hours, allowing us to probe biological activity at subcellular scales inside 3D bulk tissue. Our setups combine high lateral resolution over a large field of view with acquisition at several hundreds of frames per second which make it a promising tool for clinical applications and ...

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    14. The clinical usefulness of optical coherence tomography during cancer interventions

      The clinical usefulness of optical coherence tomography during cancer interventions

      Introduction Tumor detection and visualization plays a key role in the clinical workflow of a patient with suspected cancer, both in the diagnosis and treatment. Several optical imaging techniques have been evaluated for guidance during oncological interventions. Optical coherence tomography (OCT) is a technique which has been widely evaluated during the past decades. This review aims to determine the clinical usefulness of OCT during cancer interventions focussing on qualitative features, quantitative features and the diagnostic value of OCT. Methods A systematic literature search was performed for articles published before May 2018 using OCT in the field of surgical oncology. Based ...

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    15. In vivo imaging through the entire thickness of human cornea by full-field optical coherence tomography

      In vivo imaging through the entire thickness of human cornea by full-field optical coherence tomography

      Despite obvious improvements in visualization of the in vivo cornea through the faster imaging speeds and higher axial resolutions, cellular imaging stays unresolvable task for OCT, as en face viewing with a high lateral resolution is required. The latter is possible with FFOCT, a method that relies on a camera, moderate numerical aperture (NA) objectives and an incoherent light source to provide en face images with a micrometer-level resolution. Recently, we for the first time demonstrated the ability of FFOCT to capture images from the in vivo human cornea1. In the current paper we present an extensive study of appearance ...

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    16. Cell Motility as Contrast Agent in Retinal Explant Imaging With Full-Field Optical Coherence Tomography

      Cell Motility as Contrast Agent in Retinal Explant Imaging With Full-Field Optical Coherence Tomography

      Purpose : To use cell motility as a contrast agent in retinal explants. Methods : Macaque and mouse retinal explants were imaged with high resolution full field optical coherence tomography (FFOCT) and dynamic FFOCT, coupled with fluorescence imaging. Results : Static and dynamic FFOCT create complementary contrast from different structures within a cell. When imaging in vitro samples, static FFOCT detects steep refractive index gradients to reveal stationary structures including fibers, vessels, collagen, and cell contours, while dynamic FFOCT emphasizes metabolic activity of moving structures that are mainly intracellular, thus creating or enhancing contrast in cells that were previously hidden in noise. Dynamic ...

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      Mentions: ESPCI ParisTech
    17. Full-Field Optical Coherence Tomography as a Diagnosis Tool: Recent Progress with Multimodal Imaging

      Full-Field Optical Coherence Tomography as a Diagnosis Tool: Recent Progress with Multimodal Imaging

      Full-field optical coherence tomography (FF-OCT) is a variant of OCT that is able to register 2D en face views of scattering samples at a given depth. Thanks to its superior resolution, it can quickly reveal information similar to histology without the need to physically section the sample. Sensitivity and specificity levels of diagnosis performed with FF-OCT are 80% to 95% of the equivalent histological diagnosis performances and could therefore benefit from improvement. Therefore, multimodal systems have been designed to increase the diagnostic performance of FF-OCT. In this paper, we will discuss which contrasts can be measured with such multimodal systems ...

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    18. Dynamic multimodal full-field optical coherence tomography and fluorescence structured illumination microscopy

      Dynamic multimodal full-field optical coherence tomography and fluorescence structured illumination microscopy

      We report on the development of a configuration of a multimodal full-field optical coherence tomography (FF-OCT) and fluorescence microscope. Our system can simultaneously acquire FF-OCT and structured illumination microscopy images. Dynamic parallel evolution of tissue microstructures and biochemical environments can be visualized. We use high numerical aperture objectives to optimize the combination of the two modalities. We imaged the propagation of mechanical waves initiated by calcium waves in a heart wall to illustrate the interest of simultaneous recording of mechanical and biochemical information.

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      Mentions: ESPCI ParisTech
    19. Diffuse shear wave imaging: toward passive elastography using low-frame rate spectral-domain optical coherence tomography

      Diffuse shear wave imaging: toward passive elastography using low-frame rate spectral-domain optical coherence tomography

      Optical coherence tomography (OCT) can map the stiffness of biological tissue by imaging mechanical perturbations (shear waves) propagating in the tissue. Most shear wave elastography (SWE) techniques rely on active shear sources to generate controlled displacements that are tracked at ultrafast imaging rates. Here, we propose a noise-correlation approach to retrieve stiffness information from the imaging of diffuse displacement fields using low-frame rate spectral-domain OCT. We demonstrated the method on tissue-mimicking phantoms and validated the results by comparison with classic ultrafast SWE. Then we investigated the in vivo feasibility on the eye of an anesthetized rat by applying noise correlation ...

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      Mentions: ESPCI ParisTech
    20. High-resolution handheld rigid endomicroscope based on full-field optical coherence tomography

      High-resolution handheld rigid endomicroscope based on full-field optical coherence tomography

      Full-field optical coherence tomography (FF-OCT) is a powerful tool for nondestructive assessment of biological tissue, i.e., for the structural examination of tissue in depth at a cellular resolution. Mostly known as a microscopy device for ex vivo analysis, FF-OCT has also been adapted to endoscopy setups since it shows good potential for in situ cancer diagnosis and biopsy guidance. Nevertheless, all the attempts to perform endoscopic FF-OCT imaging did not go beyond lab setups. We describe here, to the best of our knowledge, the first handheld FF-OCT endoscope based on a tandem interferometry assembly using incoherent illumination. A common-path ...

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    21. Rapid evaluation of fresh ex vivo kidney tissue with full-field optical coherence tomography

      Rapid evaluation of fresh ex vivo kidney tissue with full-field optical coherence tomography

      Background: Full-field optical coherence tomography (FFOCT) is a real-time imaging technique that rapidly generates images reminiscent of histology without any tissue processing, warranting its exploration for evaluation of ex vivo kidney tissue. Methods: Fresh tissue sections from tumor and adjacent nonneoplastic kidney ( n = 25 nephrectomy specimens; clear cell renal cell carcinoma (CCRCC) = 12, papillary RCC (PRCC) = 4, chromophobe RCC (ChRCC) = 4, papillary urothelial carcinoma (PUC) = 1, angiomyolipoma (AML) = 2 and cystic nephroma = 2) were imaged with a commercial FFOCT device. Sections were submitted for routine histopathological diagnosis. Results: Glomeruli, tubules, interstitium, and blood vessels were identified in nonneoplastic tissue. In ...

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    22. Assessment of Sentinel Node Biopsies With Full-Field Optical Coherence Tomography

      Assessment of Sentinel Node Biopsies With Full-Field Optical Coherence Tomography

      Current techniques for the intraoperative analysis of sentinel lymph nodes during breast cancer surgery present drawbacks such as time and tissue consumption. Full-field optical coherence tomography is a novel noninvasive, high-resolution, fast imaging technique. This study investigated the use of full-field optical coherence tomography as an alternative technique for the intraoperative analysis of sentinel lymph nodes. Seventy-one axillary lymph nodes from 38 patients at Tenon Hospital were imaged minutes after excision with full-field optical coherence tomography in the pathology laboratory, before being handled for histological analysis. A pathologist performed a blind diagnosis (benign/malignant), based on the full-field optical coherence ...

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    23. Anisotropic polyvinyl alcohol hydrogel phantom for shear wave elastography in fibrous biological soft tissue: a multimodality characterization

      Anisotropic polyvinyl alcohol hydrogel phantom for shear wave elastography in fibrous biological soft tissue: a multimodality characterization

      Shear wave elastography imaging techniques provide quantitative measurement of soft tissues elastic properties. Tendons, muscles and cerebral tissues are composed of fibers, which induce a strong anisotropic effect on the mechanical behavior. Currently, these tissues cannot be accurately represented by existing elastography phantoms. Recently, a novel approach for orthotropic hydrogel mimicking soft tissues has been developed (Millon et al 2006 J. Biomed. Mater. Res. B 305–11). The mechanical anisotropy is induced in a polyvinyl alcohol (PVA) cryogel by stretching the physical crosslinks of the polymeric chains while undergoing freeze/thaw cycles. In the present study we propose an original ...

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      Mentions: ESPCI ParisTech
    24. Feature Of The Week: Feature Of The Week 1/26/14: ESPCI-ParisTech Investigates Full-Field Optical Coherence Tomograpy (FF-OCT) Shear Wave Elastography

      Feature Of The Week: Feature Of The Week 1/26/14: ESPCI-ParisTech Investigates Full-Field Optical Coherence Tomograpy (FF-OCT) Shear Wave Elastography

      Elasticity maps of tissue have proved to be particularly useful in providing complementary contrast to ultrasonic imaging, e.g., for cancer diagnosis at the millimeter scale. Optical coherence tomography (OCT) offers an endogenous contrast based on singly backscattered optical waves. Adding complementary contrast to OCT images by recording elasticity maps could also be valuable in improving OCT-based diagnosis at the microscopic scale. Static elastography has been successfully coupled with full-field OCT (FF-OCT) in order to realize both micrometer-scale sectioning and elasticity maps. Nevertheless, static elastography presents a number of drawbacks, mainly when stiffness quantification is required. Here, we describe the ...

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    1-24 of 33 1 2 »
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