Renée Chabrier

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Time-resolved diffuse optical methods have been applied to detect hemodynamic changes induced by cerebral activity. We describe a near infrared spectroscopic (NIRS) reconstruction free method which allows retrieving depth-related information on absorption variations. Variations in the absorption coefficient of tissues have been computed over the duration of(More)
Simulations based on diffusion theory that use a finite-element method and rely on an magnetic resonance imaging head model suggest that time-resolved diffuse optical techniques could provide information about the depth at which variations in perfusion take place and improve the detection of cortical activation. Experimental investigations were performed(More)
We present a new near infrared optical probe for the sentinel lymph node detection, based on the recording of scattered photons. A two wavelengths setup was developed to improve the detection threshold of an injected dye: the Patent Blue V dye. The method used consists in modulating each laser diode at a given frequency. A Fast Fourier Transform of the(More)
The estimation of one-to-one mappings is one of the most intensively studied topics in the research field of nonrigid registration. Although the computation of such mappings can be now accurately and efficiently performed, the solutions for using them in the context of binary image deformation is much less satisfactory. In particular, warping a binary image(More)
Lots of works have been recently carried out in the field of non-rigid registration to ensure the estimation of one-to-one mappings. However, warping a binary image with such transformations may alter its discrete topological properties if common resampling strategies are considered. This paper proposes an original method for warping a binary image(More)
We propose a new generic framework for segmentation of 3D digital data, based on knowledge contained in a segmentation example of similar data. The integration of prior knowledge is made by registering the image to segment on the segmentation example. Since the registration step relies on binary segmented data, segmentation and registration are performed(More)
Patent Blue V (PBV), a dye used clinically for sentinel lymph node detection, was mixed with human serum albumin (HSA). After binding to HSA, the fluorescence quantum yield increased from 5 × 10(-4) to 1.7 × 10(-2), which was enough to allow fluorescence detection and imaging of its distribution. A detection threshold, evaluated in scattering test objects,(More)
We present a new method allowing the reconstruction of 3D time-domain diffuse optical tomography images, based on the time-dependent diffusion equation and an iterative algorithm (ART) using specific points on the temporal profiles. The first advantage of our method versus the full time-resolved scheme consists in considerably reducing the inverse problem(More)
We present time-resolved methods that rely on near-infrared photons to image the optical properties and distribution of fluorescent probes in small laboratory animals. The scanner assembled in our laboratory is described. The coupled diffusion equations of excitation and fluorescence photons in highly scattering tissues were solved using the(More)