Les metastases meningees solitaires prevalentes

Objectif Intérêt d’avoir une confirmation histologique, en présence d’un processus leptoméningée solitaire dont le diagnostic de méningiome bénin est souvent évoqué en premier. Introduction Les métastases méningées sont observées de plus en plus fréquemment chez les patients connus porteur d’une néoplasie, du fait de l’allongement de la survie des patients et l’amélioration des moyens diagnostiques ; elles représentent environ 8 % des métastases du système nerveux central.Observation Nous rapportons deux observations originales de patients sans histoire néoplasique, opérés pour un processus leptomeningé solitaire dont le diagnostic préopératoire était celui d’un méningiome. L’étude histologique révélait la nature néoplasique métastatique de la lésion, alors que le bilan radiologique a permis de détecter la localisation primitive méconnue. Conclusion et discussion La découverte à l’occasion d’une imagerie cérébrale (TDM et/ou IRM) chez un patient, sans histoire néoplasique, d’une ou plusieurs lésions leptoméningées, pose un problème diagnostique. Lorsque lalocalisation est unique, le diagnostic de méningiome est évoqué en premier ; alors que les lésions inflammatoires et secondaires des hémopathies malignes représentent un diagnostic différentiel lorsque les lésions sont diffuses. Seront discutées à lumière de ces observations et d’une revue de la littérature, les aspects physiopathologiques, cliniques, paracliniques, thérapeutiques et évolutifs de cette pathologie

Weighted Harmonic and Complex Ginzburg-Landau Equations for Gray Value Image Inpainting

International audienceWe consider two second-order variational models in the image inpainting problems. The aim is to obtain in the restored region some fine features of the initial image, e.g. corners, edges, .... The first model is a linear weighted harmonic method well suited for binary images and the second one is its extension to the complex Ginzburg-Landau equation for the inpainting of multi-gray level images. The approach that we introduce consists of constructing a family of regularized functionals and to select locally and adaptively the regularization parameters in order to capture fine geometric features of the image. The parameters selection is performed, at the discrete level, with a posteriori error indicators in the framework of the finite element method. We perform the mathematical analysis of the proposed models and show that they allow us to reconstruct accurately the edges and the corners. Finally, in order to make some comparisons with well established models, we consider the nonlinear anisotropic diffusion and we present several numerical simulations to test the efficiency of the proposed approach

Weighted Harmonic and Complex Ginzburg-Landau Equations for Gray Value Image Inpainting

International audienceWe consider two second-order variational models in the image inpainting problems. The aim is to obtain in the restored region some fine features of the initial image, e.g. corners, edges, .... The first model is a linear weighted harmonic method well suited for binary images and the second one is its extension to the complex Ginzburg-Landau equation for the inpainting of multi-gray level images. The approach that we introduce consists of constructing a family of regularized functionals and to select locally and adaptively the regularization parameters in order to capture fine geometric features of the image. The parameters selection is performed, at the discrete level, with a posteriori error indicators in the framework of the finite element method. We perform the mathematical analysis of the proposed models and show that they allow us to reconstruct accurately the edges and the corners. Finally, in order to make some comparisons with well established models, we consider the nonlinear anisotropic diffusion and we present several numerical simulations to test the efficiency of the proposed approach

Syndrome coronarien aigu en post-partum secondaire à une dissection coronaire spontanée : à propos d’un cas

L'IDM per gravidique est une complication grave qui entraine une morbidité et une mortalité maternelle élevée. Bien que l'athérosclérose soit la cause d'IDM la plus fréquente dans la population générale, elle n'est observée que chez un tiers des femmes enceintes. Chez ces dernières, la cause la plus fréquente d'IDM était la dissection coronaire. Nous rapportons l'observation clinique d'une jeune femme de 24 ans, sans facteur de risque cardiovasculaire, qui a présenté un IDM antérieur étendu 15 jours après un accouchement, en rapport avec une dissection de la partie proximale de l'artère inter ventriculaire antérieure. Le traitement de cette pathologie n'est pas consensuel, et peut faire appel, selon la présentation clinique et angiographique, au traitement médical, à une revascularisation par pontage aorto-coronaire avec une résection de l'hématome de la paroi artérielle, ou à l'angioplastie transluminale. Le pronostic semble assez favorable quoique controversé

Existence of solutions and iterative approximations for nonlinear systems arising in free convection

We study the existence and the regularity of the solutions of some nonlinear partial differential system arising in the study of free convection in a two-dimensional bounded domain, modeling a porous medium saturated with a fluid. By introducing an iterative method, the closeness of such solutions by solution of linear elliptic problems is given with an exponential rate of convergence

Shape-topological differentiability of energy functionals for unilateral problems in domains with cracks and applications

International audienceA review of results on first order shape-topological differentiability of energy functionals for a class of variational inequalities of elliptic type is presented.The velocity method in shape sensitivity analysis for solutions of elliptic unilateral problems is established in the monograph (Sokołowski and Zolésio, Introduction to Shape Optimization: Shape Sensitivity Analysis, Springer, Berlin/Heidelberg/New York, 1992). The shape and material derivatives of solutions to frictionless contact problems in solid mechanics are obtained. In this way the shape gradients of the associated integral functionals are derived within the framework of nonsmooth analysis. In the case of the energy type functionals classical differentiability results can be obtained, because the shape differentiability of solutions is not required to obtain the shape gradient of the shape functional (Sokołowski and Zolésio, Introduction to Shape Optimization: Shape Sensitivity Analysis, Springer, Berlin/Heidelberg/New York, 1992). Therefore, for cracks the strong continuity of solutions with respect to boundary variations is sufficient in order to obtain first order shape differentiability of the associated energy functional. This simple observation which is used in Sokołowski and Zolésio (Introduction to Shape Optimization: Shape Sensitivity Analysis, Springer, Berlin/Heidelberg/New York, 1992) for the shape differentiability of multiple eigenvalues is further applied in Khludnev and Sokołowski (Eur. J. Appl. Math. 10:379–394, 1999; Eur. J. Mech. A Solids 19:105–120, 2000) to derive the first order shape gradient of the energy functional with respect to perturbations of the crack tip. A domain decomposition technique in shape-topology sensitivity analysis for problems with unilateral constraints on the crack faces (lips) is presented for the shape functionals.We introduce the Griffith shape functional as the distributed shape derivative of the elastic energy evaluated in a domain with a crack, with respect to the crack length. We are interested in the dependence of this functional on domain perturbations far from the crack. As a result, the directional shape and topological derivatives of the nonsmooth Griffith shape functional are obtained with respect to boundary variations of an inclusion