Identification of New Markers of Atrial Myopathy in Patients With Embolic Stroke of Undetermined Source (ESUS) From MRI 4D Data

Inclusion Criteria: Groupe1:Ischemic embolic stroke of undetermined source (ESUS) according to TOAST criteria (N =10) * Age ≥ 18 years old * Non-gap ischemic stroke diagnosed on MRI or CT scan of the brain (gap stroke defined as a cerebral infarction ≤ 1.5 cm / ≤2.0 cm on diffusion sequences). * No major cardio-embolic source (episode of atrial fibrillation or flutter \> 6min, intracardiac thrombus, LVEF \<30 percent recent myocardial infarction (\<4 weeks), mitral stenosis, valvular vegetation or infectious endocarditis). * Absence of atherosclerosis causing stenosis ≥ 50 percent of the lumen of the intra or extra cranial arteries that vascularise the infarcted cerebral area. * No other specific cause identified (arteritis, arterial dissection, migraine/vaso-spasm, toxic cause). * Affiliation to a social security scheme * Patient who signed the consent Group 2: Non-paroxysmal AF (N=10) * Age ≥ 18 years old * Subject with documented non-paroxysmal AF * Affiliation to a social security scheme * Patient who signed the consent Group 3: Healthy volunteers (N=10) Pre-inclusion criteria : * Age ≥ 45 years old * Patient with no documented cardiac or neuro-vascular history * Affiliation to a social security scheme * Patient who signed the consent * Registration on the VRB file (Volontaires Recherches Biomédicales, https://vrb.sante.gouv.fr) or response to the published announcement Criteria for inclusion : * ECG in sinus rhythm * Holter ECG: no AF * Normal Trans thoracic echocardiography * Patient with no neuro-vascular history Group 4: Stroke-ESUS or non-paroxysmal AF with cardiac MRI (N=10) * Age ≥ 18 years old * Subject with a documented stroke-ESUS or documented non-paroxysmal FA * Subject with cardiac MRI * Affiliation to a social security scheme * Subject having given its non-opposition Exclusion Criteria: Groupe1: Ischemic embolic stroke of undetermined source (ESUS) according to TOAST criteria (N =10) * Risk of pregnancy or pregnancy (proven on interrogation data or pregnancy test). * Contraindication to MRI ferromagnetic material (in particular pacemaker, implantable defibrillator, cardiac valve prosthesis, cochlear implant, neuro-stimulator, implanted automated injection material, intraocular metallic foreign body, neurosurgical and vascular clips, claustrophobia) * Less than 8 weeks after implantation of a stent * Subject participating in another intervention research including a period of exclusion still in progress at the pre-inclusion stage. Group 2: Non-paroxysmal AF (N=10) * Risk of pregnancy or pregnancy (proven on interview data or pregnancy test). * Contraindication to MRI ferromagnetic material (in particular pacemaker, implantable defibrillators, cardiac valve prosthesis, cochlear implant, neurostimulators, implanted automated injection equipment, intraocular metallic foreign body, neurosurgical and vascular clips, claustrophobia). * Less than 8 weeks after implantation of a stent * Subject participating in another intervention research including a period of exclusion still in progress at the pre-inclusion stage. Group 4: Stroke-ESUS or non paroxysmal AF with cardiac MRI (N=10) * History of neuro-vascular or cardiac pathology * Risk of pregnancy or pregnancy (proven on interrogation data or pregnancy test). * Contraindication to MRI (ferromagnetic material (in particular pacemaker, implantable defibrillator, cardiac valve prosthesis, cochlear implant, neuro-stimulator, implanted automated injection material, intraocular metallic foreign body, neurosurgical and vascular clips, claustrophobia) * Subject participating in another intervention research including a period of exclusion still in progress at the pre-inclusion stage.