Data Fusion of Left Ventricle Electro-Anatomic Mapping and Multislice Computerized Tomography for Cardiac Resynchronisation Therapy Optimization

Cardiac Resynchronization Therapy is a treatment for bi-ventricular asynchronism. It can be optimized by the identification of the most effective pacing sites. The aim of this study is to provide a helpful tool to perform this identification by the fusion of electrical and anatomical information resulting from Electro-Anatomic Mapping (EAM) data and Multislice Computerized Tomography (MSCT) imaging. EAM data provide an approximation of the left ventricle (LV) 3D-surface (SEAM). Left cardiac chambers are segmented from MSCT imaging and surfaces are reconstructed (SCT). In order to represent this information in a unified framework, a three steps method is proposed: (1) the LV is separated from the left auricle on SCT providing S ′ CT; (2) a semi-automatic rigid registration method; (3) activation time delays is applied to SEAM and S ′ CT are estimated on S ′ CT from the EAM data. This method results in a graphical interface offering to clinicians means to identify abnormal electrical activity sites

Description des collisions électroniques triplement différentielles à faible transfert d'impulsion

Simple quantum-mechanical models are found to be in strong disagreement with all (e, 2e) triplydifferential cross sections measurements out of the strict impulse collisional conditions. The second order perturbation method proposed in this article is found to reproduce the Coulomb-wave behaviour of the electron ejected from a hydrogen target under (e, 2 e) asymmetric conditions. As illustrated by the discussion of the helium atom results, this method provides the unique ab initio treatment presently known to describe (e, 2 e) measurements performed upon non-hydrogenic targets and at small momentum transfers.Les modèles quantiques simples décrivant les sections efficaces triplement différentielles de collisions (e, 2e) apparaissent grossièrement faux lorsqu'on s'écarte des conditions impulsionnelles de choc. Le traitement particulier de perturbation proposé dans cet article reproduit au second ordre la trajectoire coulombienne d'éjection d'un électron atomique, comme le montre une étude détaillée du cas de l'atome d'hydrogène. Ce traitement fournit actuellement la seule interprétation simple, en régime asymétrique de collision, des résultats expérimentaux récents dont ceux relatifs à l'atome d'hélium qui serviront également de support à la discussion

Une estimation du défaut Compton en diffusion Compton des métaux simples

A perturbation expansion has been shown to reproduce the observed asymmetries in the Compton energy-loss spectra of atomic targets. This treatment explains the Compton asymmetries in terms of a post-collisional interaction between the ejected Compton electron and the remaining ion. A theory is proposed here for an evaluation of the Compton defect in X-ray scattering measurements on simple metals. A comparison with previous experimental results on aluminium is also presented.Un traitement de perturbation permet de reproduire les asymétries observées sur le spectre Compton de cibles atomiques. Cette approche explique l'origine de telles asymétries en termes d'interactions post-collisionnelles entre l'électron éjecté, issu d'un choc Compton ionisant, et l'ion restant. Le traitement est transposé ici à la description du défaut Compton des métaux simples. Une première application est proposée et confrontée aux résultats expérimentaux antérieurs sur l'aluminium