Hemodynamic Changes in the Aorta After Endovascular Treatment of the Aortic Dissection

Aortic dissection (AD) is a serious pathology affecting one person for 300 000 habitants per year. In case of complicated AD on the descending aorta, it is necessary to perform an endovascular surgery in association with medical treatment. An endoprosthesis is implanted on the descending thoracic aorta in order to close the main intimal tear. This closure lead to an increase in the thoracic true lumen diameter, a decrease in the thoracic false lumen diameter, a better perfusion of the aortic branches. Furthermore, even in case of open surgical treatment of the ascending aorta it can be necessary to perform an endovascular treatment on the descending aorta, either to prevent and treat aneurysmal evolution or to treat patent malperfusion syndrome. CT and Magnetic Resonance angiography, by the realization of an aortic morphologic evaluation, are the two key imaging exams in the DA. Nevertheless, CT can't provide aortic dynamic evaluation, contrary to MRI. This exam, thanks to the phase-contrast sequence can measure velocity and flow data in vessels, including aorta but also true and false lumen in the AD. Thus, by verifying the perfusion of the aortic true lumen and the aortic branches it is possible to perform an early evaluation of the endovascular treatment of the DA. Actually, only one study has realized an aortic dynamic evaluation on the AD, unfortunately this study was limited to non-operated patients. In order to assess the place of MRI in the AD, the ingestigation propose to determine if phase-contrast MRI is able to evaluate the impact of the endovascular treatment on the hemodynamic state of the aorta and its branches.