Дисертації з теми "Anévrisme artériel intracrânien – Imagerie"
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Cottier, Jean-Philippe. "Angiographie par résonance magnétique : validation et optimisation pour la surveillance des anévrismes intracrâniens traités par coils GDC (Guglielmi Detachable Coils)." Tours, 2003. http://www.theses.fr/2003TOUR3303.
In our study, MR angiography was a sensitive and very specific method to access the stability of an incomplete occlusion or to diagnose recanalization of the intracranial aneurysm. The use of gadolinium did not improve the ability of 3D time of flight MR angiography to detect the presence of residual or recurrent aneurysm. In one giant aneurysm, the use of intravenous medium contrast did result in improved visualization of a residual aneurysm. With the parameters used, first-pass dynamic contrast-enhanced MR angiography images had a good resolution but its spatial resolution were lower than those on enhanced 3D time of flight MR angiography images performed in the steady state. MR angiography results was better than the analyse of the coil-ball appearance on plain radiographic to predict the instability of angiographic occlusion. The artifact due to the use of a GDC Trispan coil has been confirmed by an in vitro study
Assis, Youssef. "Détection des anévrismes intracrâniens par apprentissage profond." Electronic Thesis or Diss., Université de Lorraine, 2024. http://www.theses.fr/2024LORR0012.
Intracranial aneurysms are local dilatations of cerebral blood vessels, presenting a significant risk of rupture, which can lead to serious consequences. Early detection of unruptured aneurysms is therefore crucial to prevent potentially fatal complications. However, analyzing medical images to locate these aneurysms is a complex and time-consuming task, requiring time and expertise, and yet remains prone to errors in interpretation. Faced with these challenges, this thesis explores automated methods for the detection of aneurysms, aiming to facilitate the work of radiologists and improve diagnostic efficiency. Our approach focuses on the use of artificial intelligence techniques, particularly deep neural networks, for the detection of aneurysms from time-of-flight magnetic resonance angiography (TOF-MRA) images. Our research work is centered around several main axes. Firstly, due to the scarcity of training data in the medical field, we adopt a rapid, although approximate, annotation method to facilitate data collection. Furthermore, we propose a strategy based on small patches. In association with data synthesis, the samples are multiplied in the training database. By selecting the samples, their distribution is adjusted to facilitate optimization. Secondly, for the automated detection of aneurysms, we investigate various neural network architectures. An initial approach explores image segmentation networks. Then, we propose an innovative architecture inspired by object detection methods. These architectures, especially the latter, lead to competitive results, particularly in terms of sensitivity compared to experts. Thirdly, beyond the detection of aneurysms, we extend our model to estimate the pose of aneurysms in 3D images. This can greatly facilitate their analysis and interpretation in reformatted cross-sectional plans. A thorough evaluation of the proposed models is systematically carried out, including ablation studies, the use of metrics adapted to the problem of detection, and evaluations conducted by clinical experts, allowing us to assess their potential effectiveness for clinical use. In particular, we highlight the issues related to uncertainty in the annotation of existing databases
Yuan, Quan. "Modélisation d’anévrisme intracrânien." Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2402/document.
Intracranial aneurysms are a hazard to human health because of their high rupture rate and fatal subsequence, such as subarachnoid hemorrhage. In order to carry out a hemodynamic research in vitro on the intracranial aneurysm, a phantom is indispensable. Until now, rigid or simplified phantoms are mainly used in the literature, few among them possess sufficient properties compared with reality. The work of this thesis focuses on the methodology of manufacturing patient-specific phantoms of intracranial aneurysms as well as their implementation for different uses. The phantoms have an anatomical shape of patient’s artery and an elastic wall. They are manufactured by applying an original rapid prototyping technique. The phantoms are examined and verified in different ways. In order to perform a hemodynamic research of the phantoms, a testing platform compatible with different imaging modalities has been designed and established. 2D phase-contrast magnetic resonance angiography was applied in the hemodynamic study of the phantoms. The dynamic behavior of the artery wall, the 3D path-line of flow and the velocity field of flow were analyzed. The potential application in the clinical domain of the patient-specific phantoms was also tested in this thesis, simulations of intervention on intracranial aneurysms were carried out with the testing platform and the phantoms, the results of different treatment strategies were analyzed and compared
Gallas, Sophie. "Evaluation à moyen et long terme du traitement endovasculaire des anévrismes intracrâniens par l'optimisation des séquences d'Angiographie par Résonance Magnétique : à propos d'une cohorte de patients, avec 1036 anévrismes cérébraux suivis depuis 1998." Thesis, Tours, 2009. http://www.theses.fr/2009TOUR3302/document.
Since 1991 and the introduction of detachable intracranial coils, the endovasculary treatment of cerebral aneurysms has become an established treatment technique and has supplied surgical approach of these aneurysms. The rate of morbidity and mortality of this new technique is now well known and law. Initial Angiographic and clinical results were yet published with good outcome. Concern exists about long term reopening and the inherent risk of recurrent hemorrhage and long-term imaging follow-up is advocated. Digital Substract Hemorrhage was the gold standard for detection and follow-up of patients, but this diagnostic procedure is invasive and exposes the patient to a small risk of serious complication. MR angiography has been used as an alternative noninvasive imaging technique to assess the occlusion of coiled intracranial aneurysms with promising results. Since 1998, we have collected all patients with subarachnoid hemorrhage, and patients with cerebral aneurysms treated by endovascular approach. We have proposed different MRI sequences to valid this technique and improve this techniqueWe have compared 3D TOF to digital angiography, with sequences with injection of gadolinium. [...]
Lubicz, Boris. "Evaluation de l'apport des nouvelles techniques diagnostiques et thérapeutiques pour la prise en charge des anévrysmes intracrâniens." Lille 2, 2008. http://www.theses.fr/2008LIL2S017.
Piotin, Michel. "Augmentation du remplissage des anévrismes intracrâniens à l'aide de spirales en platine : études in vitro du taux de remplissage anévrismal, mesure des volumes anévrismaux in vitro et in vivo, applications et résultats cliniques." Paris 12, 2006. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990002382850204611&vid=upec.
Background: to fill an aneurysm with detachable platinum coils as much as possible ensure protection against further aneurysm recurrence. As a start, silicone sidewall aneurysm models were filled with various types of coils using conventional endovascular technique. Higher packing ratios (volume of inserted coils / volume of the aneurysm) were obtained with “Soft” coils when compared with “Standard” coils. As well, “Complex-shaped” coils provided with higher packing ratios than did “Helicoidal” coils. Moreover, 3D angiography was found to be more accurate than CT and MR angiographies in the determination of the aneurysm volume. Secondly, in the clinical setting, we used 3D angiography in 255 aneurysm volume measurements and calculation of packing ratios. High aneurysm packing ratios were not found to protect against aneurysm recurrence. Conversely, the aneurysm volume and the duration of angiographic follow-up were found to be statistically determinant factors of aneurysm recurrence
Turjman, Francis. "Étude expérimentale du traitement des anévrysmes par endoprothèse vasculaire." Lyon 1, 1994. http://www.theses.fr/1994LYO1T191.
Proust, François. "Intérêt du doppler transcrânien et évaluation de la morbidité et mortalité postopératoire des anévrismes intracrâniens." Rouen, 1999. http://www.theses.fr/1999ROUE06NR.
Finiels, Pierre-Jacques. "L'anévrysme de l'artère cérébelleuse postéro inférieure : mise au point anatomique, diagnostique, thérapeutique et pronostique : à propos d'une série rétrospective de 32 cas avec revue de la littérature." Montpellier 1, 1995. http://www.theses.fr/1995MON11073.
Suzat, Henri. "Contribution à l'étude des dissections traumatiques de l'artère carotide interne extra-crânienne secondaires aux traumatismes crânio-cervicaux fermes : à propos de sept cas et revues de la littérature." Saint-Etienne, 1989. http://www.theses.fr/1989STET6004.
Vallée, Jean-Noël. "Système tridimensionnel d'aide à la navigation et au traitement endovasculaire en temps réel pour dispositif d'angiographie interventionnelle." Paris 13, 2003. http://www.theses.fr/2003PA132031.
To treat an intracranial aneurysm, the interventional neuroradiologist enters the skull from a vascular access device, making browsing, controlled angiographic imaging, microcatheters and materials, within the vessels of the brain into of the aneurysm to occlude. In his practice, he takes advantage of digital angiography equipped with high resolution fluoroscopy and rotational angiography for the reconstruction of three-dimensional reference images initially acquired in a reference plane, and the limits of the 3D imaging by rotational angiography acquired with only a diagnostic value, pre-and / or post-treatment. The research presented in this thesis was born from the ambition to design and develop a tri-dimensional system, improved over all or part of this issue, guidance or aid to navigation in endovascular imaging. The method of the invention recalculates and displays a dynamic, automatic, interactive and real-time depending on the setting of angiography device, or volume and / or video projection volume from the volume of reference region of interest initially reconstructed from images acquired by rotational angiography or volumes and / or images resulting from the mapping by superposition, subtraction or merger of volumes and / or images and recalculated with the fluoroscopic image (or volume) of active parameters corresponding fluoroscopy, which allows the user at any time during surgery, to optimize its decisions and treatment strategies, navigation instruments and equipment, control of his actions and therapeutic Evaluation of therapeutic results. The expected consequences are, firstly, improving the effectiveness and safety of the intervention, and on the other hand, decreased procedure times of radiation exposure, and the quantities of contrast medium. French patent of 05/03/2002 with extension PCT International No. FR03/01075 of 04/04/2003
Langlois, Olivier. "Chirurgie des anévrismes intracrâniens et thromboses artérielles post-opératoires : Étude sur une série de 250 patients." Rouen, 1994. http://www.theses.fr/1994ROUEM146.
Bourcier, Romain. "Génétique et physiopathologie des formes familiales d'anévrismes intracrâniens." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT1013.
Intracranial Aneurysms (lA) are defined by an acquired hernia of the arterial wall arising on arterial bifurcations. There is a characteristic topographical predilection for the vessels of the skull base. Few studies have addressed the role of genetic factors in the familial forms of lA. We have conducted an original study thanks to biocollection built to identify one or more genetic variations causally related to lA formation. Our study used a high-throughput exome sequencing approach. The clinical phenotyping and the recruitment of relevant patients is a key prerequisite in order to identify genetic variations. This step consists in the identification of familial forms of lA rigorously phenotyped over several generations. The GAIA project has initially permitted the recruitment of 4 large families originating from the region of Nantes and Vendée. These families were genetically informative and an autosomal dominant transmission was suggested. High-throughput exome sequencing revealed a mutation shared by all members with lA in one of these families. This mutation is located in a gene encoding for a circulating protein related to angiogenesis (ANGPTL6). The serum level of ANGPTL6 could appear as a biomarker of lA. The initial study is now deployed toward a nationwide biocoliection; The ICAN project, in order to identify biological signaling pathways of interest, thus making it possible to better understand pathophysiology of lA. We finally aim to propose a personalized management of lA
Bresson, Damien. "Étude de l’écoulement sanguin dans un anévrysme intracrânien avant et après traitement par stent flow diverter : quantification par traitement d’images de séquences angiographiques 2D." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2308/document.
Intracranial aneurysms treatment based on intra aneurismal flow modification tend to replace traditionally coiling in many cases and not only complex aneurysms for which they were initially designed. Dedicated stents (low porosity, high pores density stents) called “flow diverter” stents are deployed across the neck of the aneurysm to achieve this purpose. The summation of three different mechanisms tend to lead to the healing of the aneurysm: immediate flow alteration due to the mechanical screen effect of the stent, physiological triggering of acute or progressive thrombus formation inside the aneurysm’s pouch and long term biological response leading in neointima formation and arterial wall remodeling. This underlying sequence of processes is also supposed to decrease the recanalization rate. Scientific data supporting the flow alteration theory are numerous and especially computational flow dynamics (CFD). These approaches are very helpful for improving biomechanical knowledge of the relations between blood flow and pathology, but they do not fit in real-time treatments. Neuroendovascular treatments are performed under dynamic x-ray modality (digital subtracted angiography a DSA-).However, in daily practice, FD stents are sized to the patient’s 3D vasculature anatomy and then deployed. The flow modification is then evaluated by the clinician in an intuitive manner: the decision to deploy or not another stent is based solely on a visual estimation. The lack of tools available in the angioroom for quantifying in real time the blood flow hemodynamics should be pointed out. It would make sense to take advantage of functional data contained in contrast bolus propagation and not only anatomical data. Thus, we proposed to create flow software based on angiographic analysis. This software was built using algorithms developed and validated on 2D-DSA sequences obtained in a swine intracranial aneurysm model. This intracranial animal model was also optimized to obtain 3D vascular imaging and experimental hemodynamic data that could be used to realize realistic computational flow dynamic. In a third step, the software tool was used to analyze flow modification from angiographic sequences acquired during unruptured IA from patients treated with a FD stent. Finally, correlation between flow change and aneurysm occlusion at long term follow-up with the objective of identifying predictive markers of long term occlusion was performed
Mérillon, Catherine. "Suivi du vasospasme artériel de l'hémorragie méningée par le doppler transcranien." Bordeaux 2, 1991. http://www.theses.fr/1991BOR2M064.
Dehail, Patrick. "Séquelles neuropsychologiques après rupture d'anévrysme de l'artère communicante antérieure, à propos de 71 cas." Bordeaux 2, 1997. http://www.theses.fr/1997BOR23091.
Devarrieux, Laure. "Les troubles de l'appréhension du temps : à propos d'une étude comparative entre un groupe de patients souffrant d'une rupture d'anévrysme de l'artère communicante antérieure et un groupe de patients atteints de maladie d'Alzheimer." Caen, 1990. http://www.theses.fr/1990CAEN3005.
La, Folie Trévor. "Myxome cardiaque et manifestations neurologiques : étude rétrospective sur 10 observations." Bordeaux 2, 1998. http://www.theses.fr/1998BOR2M128.
Gauvrit, Jean-Yves. "Evaluation et optimisation des techniques d'ARM avec injection en pathologie neuro-vasculaire." Lille 2, 2005. http://www.theses.fr/2005LIL2S010.
MRI and the whole of the software of post treatments hold a capital place in the exploration of cerebral arteriovenous malformations and intracranial aneurysms. In cerebral arteriovenous malformations (cAVM), the non-invasive techniques of angiography (MRA and AngioCT) provide a precise anatomical study but contrary to the conventional angiography do not bring any hemodynamic information however essential. A new technique of MRA, the dynamic MRA, based on a repeated acquisition of images and an image subtraction, makes it possible to obtain this kinetic information. Our work showed the interest of this technique in the exploration of cAVM but also in other intracranial vascular diseases (dural fistulas, aneurysms, venous thrombosis) at the same time in the detection of pathology but also in the definition of prognostic arguments in particular with the hemorrhagic risk. Initially acquired with 2D technique, the use of the techniques of parallel imagery, allowed the development of a three-dimensional (3D) dynamic MRA reconciling high space resolution and short temporal resolution. We showed the interest of the 3D dynamic MRA in the follow-up of radiosurgically treated cAVM by analyzing the reduction of size of the nidus or the disappearance of the venous drainage. The endovascular treatment of intracranial aneurysms has occupied, for a few years, an important place in the therapeutic assumption. The clinical and radiological follow-up is essential because the risk of repetitions remains badly documented. Whereas the techniques of MRA with injection are the sequences of reference in cervical vascular pathology, they are developed little in intracranial exploration because of venous overlaps. However, their capacities to obtain a high contrast and to reduce the flow artefacts make of them, techniques adapted to the monitoring of treated aneurysms by coils. Our work showed the contribution of the MRA with gadolinium injection in the detection of the aneurismal recurrences but also the interest in the management of the early and late recanalisations
Bourgeois, Philippe. "Hemorragies méningées par dissections spontanées des artères intracraniennes." Bordeaux 2, 1993. http://www.theses.fr/1993BOR23121.
Fodoup, Fotso Louis. "Pan hypopituitarisme révélateur d'une compression hypophysaire par anévrysme géant de la carotide interne dans le sinus caverneux : à propos d'un cas." Montpellier 1, 1995. http://www.theses.fr/1995MON11137.
Saccardy, Fabrice. "Intérêt du scanner multicoupe dans la détection et la caractérisation des anévrismes intracrâniens : comparaison avec l'artériographie numérisée." Poitiers, 2004. http://www.theses.fr/2004POIT1061.
Del, Missier Nathalie. "Matériovigilance et traçabilité des dispositifs médicaux implantables utilisés en neuroradiologie vasculaire dans le traitement des anévrismes intracraniens : exemple des GDC R à l'hôpital Sainte-Anne." Paris 5, 1998. http://www.theses.fr/1998PA05P210.
Eker, Omer Faruk. "Impact de l'anévrisme intracrânien sur l'hémodynamique de l'artère porteuse : de l’observation in vitro à l’exploration in vivo." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1046/document.
Intracranial aneurysms are the most common lethal predisposition amongst young adults. Its understanding remains limited to date while the development of new innovative endovascular treatments are increasingly available and allow for the treatment of more and more complex aneurysms with a non negligeable rate of complications. Most of the previous studies on intracranial aneurysms are based on low informative clinical series and the use of limited numerical simulation methods. They almost exclusively target the intrasaccular mechanical phenomena irrespective of the changes in the parent vessel induced by the aneurysm. In vitro, the use of silicone aneurysms embedded in a cardiovascular simulator showed an impact of the aneurysm on the the parent vessel flow conditions characterized by a decrease of its resistance. In vivo, flow MRI allowed to quantify this effect by analyzing the volumetric flow rate curves. Downstream to the aneurysm, the blood flow was dampened and presents a systolic diastolic demodulation with a collapse of resistive and pulsatility indexes. This effect was strongly correlated to the aneurysm volume. The flow diverter stents allowed for a measurable « hemodynamic reconstruction » of the parent vessel by restoring a normo modulated flow, and normal resistive and pulsatility indexes. An original method for the segmentation of internal carotid artery in 2D phase contrast MRI was proposed. It is based on the application of the Fourier Transform on the phase images and by taking into account the temporal coherence of velocities within the voxel. The method was characterized and compared to two reference methods
Wei, Yiyi. "Toward real-time simulation of aneurysm coil embolization using the discrete exterior calculus method." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10034/document.
Over the last decade, remarkable progress has been made in the field of endovascular treatment of aneurysms. Technological advances continue to make it possible for a growing number of patients with cerebral aneurysms to be treated with a variety of endovascular strategies, essentially using detachable platinum coils. Yet, coil embolization remains a very complex medical procedure for which careful planning must be combined with advanced technical skills in order to be successful. In this context, a computer-assisted planning system, allowing interventional radiologists to interactively select different coils and test their behavior in a patient-specific environment, could make a difference. This requires to not only model the blood and coil behavior in a patient-specific aneurysm geometry, but also to simulate the interaction between coil(s) and the complex flow occurring within aneurysm in (near) real time. In order to achieve accurate and fast simulation, we introduce the Discrete Exterior Calculus (DEC) method to hemodynamic simulation for the first time. The DEC method, initially introduced in the field of computer graphics, was aimed at visually convincing results, but not physical accuracy. A detailed analysis of the results and comparison with a reference software are performed to understand the accuracy, stability and computational efficiency of the method, as well as the factors affecting these aspects. We improve the numerical stability of the DEC method by using more advanced backtracking schemes, and more importantly by optimizing quality of the mesh used in the computation. Additionally, an optimal trade-off between accuracy and computational time is obtained to simulate the blood flow in (near) real time. Based on this new method for blood flow simulation, we describe a complete process for patient-specific simulation of aneurysm coil embolization, from mesh generation with medical datasets to computation of blood-coil bilateral influence. We propose a new approach to real-time simulation of the twofold interactions, first involving the impact of blood flow on the coil during the initial stages of its deployment, and second concerning the decrease of blood velocity within aneurysm, as a consequence of coil packing. This allows dynamical planning coil embolization for two key steps in the procedure: choice and placement of the first coil, and assessment of the number of coils necessary to reduce the blood velocity within aneurysm. The coil embolization procedure is simulated within patient-specific aneurysms in real time, and pre- and post-operative status is reported. Our simulated results demonstrated that the bilateral influence is essential in the context of planning the coil embolization surgery. Besides, we propose a preliminary framework for the simulation of blood-vessel interaction during the process of aneurysm growth. The results of the two-dimensional simulation using actual patients data sets is encouraging
Pulcrano-Nicolas, Anne-Sophie. "Recherche de biomarqueurs circulants de la survenue du vasospasme chez des patients souffrant d'hémorragie sous-arachnoïdienne." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS312.
Subarachnoid hemorrhage (SAH) morbidity and mortality are not solely due to the aneurism rupture but also to the delayed neurological ischemic disorders (DNI) that could happen. Among these, vasospasm is a severe complication occurring between the 4th and 12th day after the bleeding for one third of the SAH patients. To date, there exists no predictive marker of its happening, which force physician to give any SAH patient a preventive treatment against its occurrence not exempt of severe side effects. VASOGENE cohort was built up to search by omic approaches biomarkers of vasospasm occurrence to identify at risk patients. The thesis' aim is to identify circulating biomarkers of vasospasm occurrence post SAH. Two groups of patients were present in this cohort: aSAH patients developing (VSP+) or not (VSP-) a vasospasm. A first study comparing whole blood microRNA between VSP+ and VSP- enabled us to identify has-miR-3177-3p and LHDA as good candidate biomarkers. A second work was performed on transcriptomic data comparing mRNA levels between VSP+ and VSP-. We identified another candidate gene that is currently submitted
Ballet, Anne-cécile. "Traitement neurochirurgical et endovasculaire des anévrismes intracrâniens : approche économique de deux alternatives thérapeutiques sur le CHU de Bordeaux." Bordeaux 2, 2000. http://www.theses.fr/2000BOR2P082.
Gentric, Jean-Christophe. "La diversion de flux dans le traitement des anévrismes cérébraux : des études pré-cliniques aux études cliniques." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0027/document.
Flow Diversion is one of the relevant technical improvements of the past decade in the endovascular treatment of cerebral aneurysms. When the efficacy and safety of a new tool allow treating challenging aneurysms, this adoption in daily practice can be fast even if the benefit of use is not clearly, scientifically show. We performed a systematic review of studies of these stents called “Flow Diverters” (FD) in animal models. Then we performed 4 animal studies in models we create in order to isolate the propriety of the FD we wanted to study. By using this methodology, we have been able to show that Flow Diversion is more likely to occlude small neck aneurysms, aneurysms in which the jailed branch has been occluded, or when the operator compact the FD in order to decrease the porosity of the device. In a 6th study, we test the result of the use of a clip to occlude a FD. Regarding the results of the test, we recommand to avoid clipping FDs.Then by using a questionaire; we showed the poor agreement of using FD in daily practice by using clinical vignettes. Then we presented the design and the result of the first randomized clinical study on flow diverters FIAT (Flow diversion In Aneurysm Treatment)
Labeyrie, Paul-Emile. "Amélioration des stratégies thérapeutiques dans la pathologie anévrysmale intracânienne." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC404/document.
Intracranial aneurysm (IA) is a specific morphological abnormality of the cerebral arteries that exposes to devastating intracranial bleeding. Despite the progress made in the curative treatment, no preventive treatment of IA formation has been proven in humans. The lack of non-invasive treatment and consensus on the treatment of unruptured IA are the consequences of the lack of knowledge of the physiopathological mechanisms of aneurysmal disease. All of the work presented here aims to better understand the mechanisms of intracranial aneurysmal pathology, which may be the basis of new preventive strategies improving the treatment of IA.We first studied the influence of cervical artery abnormalities on IA formation. In this study, we performed a case-control study whose main objective was to study the association between morphologic abnormalities of cervical arteries and the presence of IA. The secondary objectives were first to examine whether this association varied according to whether or not the aneurysm was broken, and secondly to examine whether the severity of the cervical arterial abnormalities was related to the severity of the aneurysmal pathology. We report that the prevalence of angiographic abnormalities in patients harboring IA is high. In addition, the incidence of a rare pathology, fibro-muscular dysplasia is very high in patients with IA compared to the general population. The presence of angiographic abnormalities has no impact on the rupture of the IA, nor on other aspects such as their size, numbers or shape. In our study, we believe that the association between angiographic abnormalities and IA seems to be explained by the hypothesis of a vulnerability of the arterial wall (a particular pathological condition of the arterial wall at the origin of IA formation). This pathological condition would affect the whole cerebral vasculature and cervical arteries. IA would thus be the clinical manifestations of more silent vascular pathologies affecting the wall of all vessels. The morphological abnormalities of the cervical arteries testify sensitively but not very specifically of the association of the arterial wall diseases with the presence of IA.In a second study, we try to describe and characterize an unprecedented pathway of formation and growth of IA : the pathway of fibrinolysis via tissue-type plasminogen activator (tPA). Our data suggest that tPA present in the bloodstream is sufficient to promote formation and rupture of aneurysms. We therefore proposed that vascular tPA was one of those responsible for training IA. We also noted a certain continuity in the time of the influence of the tPA on the matrix remodeling. We therefore proposed vascular tPA as a possible new target to prevent progression and rupture of IA. Various experiments have been undertaken to selectively inhibit tPA and the preliminary results are encouraging and open the way to an unprecedented non-invasive therapeutic strategy. It is also conceivable that these different approaches could be combined with each other and with matrix agents directly targeting tPA activity in the AIC wall. The improvement of therapeutic strategies in intracranial aneurysmal pathology is definitely an topic of research whose possibilities are huge and the results necessary and expected
Sanchez, Mathieu. "Identification du risque individuel de rupture des anévrysmescérébraux intra crâniens : une approche biomécanicienne." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20257/document.
The individual risk of rupture of cerebral aneurysm is a major stake in the clinical treatment. The aneurismal rupture occurs when the intra-parietal stress exceeds the rupture stress of the material of the aneurismal wall. The goal of our study is to be a step toward a new biomechanical measure of an individual risk of rupture of cerebral aneurysm. First, an experimental study was performed to characterize the biomechanical behavior of the aneurismal wall on 16 samples of aneurysms removed by neurosurgery. The experimentation on the samples allowed us to reach three main categories of tissues for each sex (female and male): soft, intermediate and stiff. All the unruptured aneurysms belong to the stiff category or the intermediate category and all the ruptured aneurysms belong to the soft category. This is allowed us to give prominence to the correlation between the risk of rupture and the properties of the material of the aneurismal wall. Then, Fluid/Structure interaction computations (FSI) were performed to compare the strain of a “patient-specific” aneurysm composed of a degraded and undegraded material. The results show that the properties of the material have a major impact on the scope of the aneurismal volume variation over the cardiac cycle. The volume variation changes depending on the properties of the tissue are potentially viewable by medical imaging. A study of the uncertainties of the parameters is also proposed and shows the robustness of the results. We also demonstrated on 12 cases of “patient-specific” aneurysms that a significant difference stiff exists in terms of volume variation over the cardiac cycle between an aneurysm composed of a stiff and a soft material. This study suggests that the aneurismal volume variation could be used as a basis for an evaluation of the individual risk of rupture of cerebral aneurysms