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Imagerie spirale du tenseur de diffusion à 7T: application au cerveau de rat traumatisé.

Abstract : The purpose of this thesis was to implement a robust fast diffusion tensor imagines sequence on a 7-T small bore system. We implemented a Twice Refocused Spin Echo sequence in order to cancel eddy currents problems on our system. Spiral k-space acquisition was preferred to EPI for its insensitivity to motion and flow artifacts, very important in diffusion imaging. We developed software (in Matlab) to reconstruct spiral diffusion weighted and tensor images as well as maps of tensor derived parameters: anisotropy indices, and color maps. We used a free software (MedINRIA DTI Track) developed by P. Fillard from INRIA Nice-Sofia Antipolis in order to track white matter fibers in the rat brain. After preliminary calibrations as well as validations on different phantoms and healthy rat brain, the implemented sequence was applied to traumatic rat brain injury. In this model, developed in our laboratory, the traumatism was induced by impact-acceleration method. The aim of this study was to early characterize post-traumatic cerebral edema by the mean of diffusion tensor imaging. Variations of mean diffusivity in the traumatic rat brain provided information about the type of cerebral edema induced by traumatic brain injury. Modifications of anisotropy indices in corpus callosum of traumatic rat brain provided evidence for presence of diffuse axonal injury. Fiber tracking in the corpus callosum of rat brain showed axonal rupture on the center of traumatic rat corpus callosum.
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https://tel.archives-ouvertes.fr/tel-00296800
Contributor : Yohan van de Looij <>
Submitted on : Tuesday, July 15, 2008 - 12:13:51 PM
Last modification on : Friday, November 6, 2020 - 4:08:30 AM
Long-term archiving on: : Friday, May 28, 2010 - 10:08:55 PM

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  • HAL Id : tel-00296800, version 1

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Yohan van de Looij. Imagerie spirale du tenseur de diffusion à 7T: application au cerveau de rat traumatisé.. Neurosciences [q-bio.NC]. Université Joseph-Fourier - Grenoble I, 2006. Français. ⟨tel-00296800⟩

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