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Acquisition et traitement de l’imagerie par Résonance Magnétique en contraste de phase pour la quantification des écoulements cérébraux du sang et du Liquide Cérébro-Spinal sous influence respiratoire

Abstract : To date, the effects of arrhythmia and respiration on cerebral blood flow dynamics are not well understood. The "2D Cine Phase Contrast " (CINE-CP) sequence obtained in magnetic resonance imaging (MRI) quantifies non-invasively the vascular flows and the cerebrospinal fluid (CSF) flows. However, it is limited by its temporal resolution because it gives access to an average flow curve reconstructed from hundreds of cardiac cycles. We have a new MRI sequence called "Echo Planar Imaging" in phase contrast (EPI-CP) that allows to quantify velocities "in real time" and offers great advantages for the study of the influence of respiration on blood and CSF dynamics in the cranio-spinal system. However, EPI-CP provides a larger number of images with reduced image quality, which causes difficulties for EPI-CP post-processing. To our knowledge, there is no software dedicated to EPI-CP image processing. Therefore, the thesis covers three main objectives: firstly, optimization of the EPI-CP protocol and validation of the accuracy of EPI-CP in quantifying cerebral circulation of arterial, venous and CSF flows; secondly, development of a dedicated software for post processing EPI-CP images of the cranio-spinal system; and finally, quantification of the influence of respiration on blood and CSF flows in the cranio-spinal system. To achieve these objectives, as a first step, the EPI-CP protocol was optimized using a flow phantom to achieve calibrated, pulsatile physiological flows inside the MRI. The accuracy of the EPI-CP was evaluated by comparison with the reference CINE-CP sequence. The effects of pixel size and velocity encoding in the EPI-CP were investigated. In the second step, a post-processing software was developed to visualize, segment and analyze the DICOM images of the EPI-CP sequence. The software also offers the possibility to import a respiratory signal which is recorded during the acquisition to quantify the effect of respiration on the vascular and CSF flows. Finally, with this EPI-CP post-processing software, in vivo validation of the accuracy of the EPI-CP was performed on a population of 16 adult volunteers. In addition, a quantification study of the effect of respiration on cerebral arteries was performed on a population of 12 adult volunteers.
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https://hal.archives-ouvertes.fr/tel-03749817
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Submitted on : Thursday, August 11, 2022 - 2:00:08 PM
Last modification on : Friday, August 12, 2022 - 3:48:56 AM

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  • HAL Id : tel-03749817, version 1

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Pan LIU. Acquisition et traitement de l’imagerie par Résonance Magnétique en contraste de phase pour la quantification des écoulements cérébraux du sang et du Liquide Cérébro-Spinal sous influence respiratoire. Imagerie. Université de Picardie Jules Verne, 2021. Français. ⟨tel-03749817⟩

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