1. Articles from Olivier Thouvenin

    1-12 of 12
    1. 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
    2. 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
    3. 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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    4. 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
    5. 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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    6. 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
    7. En face coherence microscopy [Invited]

      En face coherence microscopy [Invited]

      En face coherence microscopy or flying spot or full field optical coherence tomography or microscopy (FF-OCT/FF-OCM) belongs to the OCT family because the sectioning ability is mostly linked to the source coherence length. In this article we will focus our attention on the advantages and the drawbacks of the following approaches: en face versus B scan tomography in terms of resolution, coherent versus incoherent illumination and influence of aberrations, and scanning versus full field imaging. We then show some examples to illustrate the diverse applications of en face coherent microscopy and show that endogenous or exogenous contrasts can add ...

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      Mentions: ESPCI ParisTech
    8. Intracellular dynamics measurements with full field optical coherence tomography suggest hindering effect of actomyosin contractility on organelle transport

      Intracellular dynamics measurements with full field optical coherence tomography suggest hindering effect of actomyosin contractility on organelle transport

      Intracellular motion can be quantitatively monitored in tissues using coherence-gated microscopic techniques. With full-field optical coherence tomography (FFOCT), the use of high numerical aperture microscope objectives provides a high resolution mapping of intracellular dynamics that are probed with subwavelength sensitivity. In the upper temporal bandwidth that we have used (1-6 Hz) the main contribution to the dynamic signal arises from the overall dynamical, optically heterogeneous cytoplasm. We propose a method to specifically study the impact of actomyosin contractility on the intracellular dynamic signal by performing high throughput, comparative measurements of multicellular aggregates with and without blebbistatin action, a selective inhibitor ...

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      Mentions: ESPCI ParisTech
    9. Appearance of the Retina With Full-Field Optical Coherence Tomography

      Appearance of the Retina With Full-Field Optical Coherence Tomography

      Purpose : To interpret full-field optical coherence tomography (FFOCT) images of ex vivo retina. Methods : Flatmounted retinas of human, primate, pig, sheep, rat, and mouse were imaged using FFOCT. To identify retinal ganglion and amacrine cells, fixed samples immunolabeled against Tuj1 and Brn3a or live samples labeled in vitro with green fluorescent protein (GFP) were analyzed by combining FFOCT, fluorescence confocal microscopy (FCM), and fluorescence-FFOCT. To investigate postmortem tissue changes, time series were acquired over 48 hours and on fresh versus fixed tissue. Results : With FFOCT, cell types and features such as nerve fiber bundles and RGC somas were resolved without ...

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    10. Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by interferometric signals temporal analysis

      Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by interferometric signals temporal analysis

      We developed a new endogenous approach to reveal subcellular metabolic contrast in fresh ex vivo tissues taking advantage of the time dependence of the full field optical coherence tomography interferometric signals. This method reveals signals linked with local activity of the endogenous scattering elements which can reveal cells where other OCT-based techniques fail or need exogenous contrast agents. We benefit from the micrometric transverse resolution of full field OCT to image intracellular features. We used this time dependence to identify different dynamics at the millisecond scale on a wide range of organs in normal or pathological conditions.

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    11. Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by temporal analysis of interferometric signals

      Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by temporal analysis of interferometric signals

      We developed a new endogenous approach to reveal subcellular metabolic contrast in fresh ex vivo tissues taking advantage of the time dependence of the full field optical coherence tomography interferometric signals. This method reveals signals linked with local activity of the endogenous scattering elements which can reveal cells where other imaging techniques fail or need exogenous contrast agents. We benefit from the micrometric transverse resolution of full field OCT to image intracellular features. We used this time dependence to identify different dynamics at the millisecond scale on a wide range of organs in normal or pathological conditions.

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      Mentions: ESPCI ParisTech
    12. 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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    1-12 of 12
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  2. Topics in the News

    1. (12 articles) ESPCI ParisTech
    2. (5 articles) Aquyre Biosciences
    3. (1 articles) Cornell University
    4. (1 articles) Sun Yat-Sen University
    5. (1 articles) University of Pittsburgh
    6. (1 articles) Cardiovascular Research Foundation
    7. (1 articles) Harvard University
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    Rapid evaluation of fresh ex vivo kidney tissue with full-field optical coherence tomography Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by temporal analysis of interferometric signals Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by interferometric signals temporal analysis Appearance of the Retina With Full-Field Optical Coherence Tomography Intracellular dynamics measurements with full field optical coherence tomography suggest hindering effect of actomyosin contractility on organelle transport En face coherence microscopy [Invited] Dynamic multimodal full-field optical coherence tomography and fluorescence structured illumination microscopy Full-Field Optical Coherence Tomography as a Diagnosis Tool: Recent Progress with Multimodal Imaging Cell Motility as Contrast Agent in Retinal Explant Imaging With Full-Field Optical Coherence Tomography Probing dynamic processes in the eye at multiple spatial and temporal scales with multimodal full field OCT Macular and choroidal perfusion using optical coherence tomography angiography in type-2 diabetic patients without diabetic retinopathy Short-term evaluation of clear corneal incision after phacoemulsification using anterior segment optical coherence tomography