Search results for "Aorte"
showing 6 items of 6 documents
The compliance modelling of the pathology aorta of the type of aneurism
2015
The Abdominal Aorta Aneurysm (AAA) is a pathology that is defined by a localized and permanent dilation of the artery and which involves over 8.8% of the seniors. Currently, when a patient has a dilatation of the aorta leading to a surgery because of the rupture risk, the therapeutic decision is made depending on the diameter of the aneurysm. To determine this diameter, it is usually conducted an examination by medical imaging (ultrasound, CT, MRI...). However, it notes that the diagnosis can’t be satisfied with a single dimensional measurement face to induced risks: first of all, when the diameter exceed a certain growth, the risk of rupture can reach 50% but more than 5% of surgical proce…
Intercomparison between MRI and stereovision/PIV measurements for diagnosis of aorta pathologies
2015
International audience; The objective of the study is to validate the ability of magnetic resonance imaging (MRI) to perform measurements of deformations and internal flow of an aortic phantom with aneurysm. An in-vitro measurement experimental device to simulate blood flow was developed. It was tested within MRI and within stereovision and particle image velocimetry (PIV) devices. The measurement results are well correlated and can be used to establish a preoperative diagnosis based on computed parietal stresses with a finite element model (FEM).
Comparaison de la mesure des déformations de fantômes de l’aorte à partir d’image obtenues par IRM et stéréovision
2015
International audience; The study of the wall strain distribution could be helpful to improve the decision criterion for surgery of aortic aneurysm. Recently, numerical simulations can complete the data obtained from imaging measurement in order to develop reliable models. However, the used medical imaging tools are not experimentally validated, in metrological point of view. The aim of this study focused on accuracy and reliability of measurement obtained from kinetic MR sequences. The measures of deformations from MRI were compare to those obtained from stereovision system. Cylindrical phantom of silicone material similar to arterial behavior simulated a symmetric aneurysm was designed. A…
Biomechanics of human ascending aorta and aneurysm rupture risk assessment
2021
Ascending aortic aneurysms (AsAA) and aortic dissections are life-threatening cardiovascular diseases. The main criteria for determining surgical intervention of AsAA are the maximum diameter or the increasing annual rate of the aneurysm. The mortality of the untreated aortic dissection can be 21% to 74%, depending on the delay of hospital admission.Our study aims to characterize the biomechanical properties of the ascending aorta and propose a patient-specific approach to assess the risks of rupture. The purpose of this PhD work is multifold.On the one hand, biaxial tensile tests were performed on AsAA samples obtained from one hundred patients with surgery of AsAA. The impact on the diffe…
Tomographic image processing for the morphological and metrological study of Valsalva sinuses
2012
This Phd thesis deals with the design and the use of image processing tools in order to allow a reliable and objective study of the sinuses of Valsalva which are important cavities of the aortic root. The proposed methods can be applied on cine-MR sequences and CT examinations without any change in the settings between two examinations.Firstly, we studied the morphology of this anatomical area and its constant properties in all images of the dataset. Sinuses are one of the main bright organs with limited movements. Hence a new algorithm has been designed. It detects and characterizes each bright organ by a single trajectory. Various tools of mathematical morphology are used for this step, a…
Étude du comportement de l'aorte dans le cadre de pathologie de type anévrisme
2013
International audience; Lorsqu'un patient présente une dilatation de l'aorte impliquant la possibilité d'une intervention chirurgicale (en raison du risque de rupture), la décision thérapeutique est prise en fonction du rapport des diamètres de l'artère. Toutefois cette mesure dimensionnelle est insuffisante et doit être compléter d'une estimation de la compliance de l'artère. C'est un travail complexe prenant en compte divers aspects. C'est une première approche qui présentée dans ce papier. Elle a pour objectif de quantifier les déformations de fantômes (répliques) en silicone ayant des géométries simplifiées mais proches de celle des patients présentant une pathologie de type anévrisme. …