66 research outputs found

    In vivo laser Doppler holography of the human retina

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    The eye offers a unique opportunity for non-invasive exploration of cardiovascular diseases. Optical angiography in the retina requires sensitive measurements, which hinders conventional full-field laser Doppler imaging schemes. To overcome this limitation, we used digital holography to perform laser Doppler perfusion imaging of the human retina in vivo with near-infrared light. Wideband measurements of the beat frequency spectrum of optical interferograms recorded with a 39 kHz CMOS camera are analyzed by short-time Fourier transformation. Power Doppler images and movies drawn from the zeroth moment of the power spectrum density reveal blood flows in retinal and choroidal vessels over 512 ×\times 512 pixels covering 2.4 ×\times 2.4 mm2^2 on the retina with a 13 ms temporal resolution.Comment: 5 pages, 5 figure

    Poissons de la Guyane Française

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    Pulsatile microvascular blood flow imaging by short-time Fourier transform analysis of ultrafast laser holographic interferometry

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    We report on wide-field imaging of pulsatile microvascular blood flow in the exposed cerebral cortex of a mouse by holographic interferometry. We recorded interferograms of laser light backscattered by the tissue, beating against an off-axis reference beam with a 50 kHz framerate camera. Videos of local Doppler contrasts were rendered numerically by Fresnel transformation and short-time Fourier transform analysis. This approach enabled instantaneous imaging of pulsatile blood flow contrasts in superficial blood vessels over 256 x 256 pixels with a spatial resolution of 10 microns and a temporal resolution of 20 ms.Comment: 4 page

    A propos de l'article "Il y a 100 ans : souvent futaie varie"

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    Extended resections for bronchogenic carcinoma invading the superior vena cava system

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    Extended resection of non-small-cell lung cancer (NSCLC) involving the superior vena cava (SVC) system is infrequently performed and oncologic benefits are still uncertain
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