ECAA Brain MRI: Seeking the Link Between Extracranial Carotid Artery Aneurysms and Small Vessel Disease

Inclusion Criteria: * Patient older than 18 years registered in the CAR treated with conservative therapy * Willingness and ability to participate in all scheduled procedures outlined in the protocol * Understanding of the Dutch language * Patient is able and willing to give informed consent. Exclusion Criteria: * Inclusion criteria are not met * Subjects registered in the CAR that have undergone surgical or endovascular treatment of the ECAA * Contradictions for MRI, such as 1) metallic objects in or around the body (e.g. cardiac implantable electronic device such as pacemakers and implantable cardioverter defibrillators (ICD); 2) claustrophobia, 3) pregnancy. * Other major neurological or psychiatric conditions affecting the brain and interfering with the study design (e.g. multiple sclerosis, epilepsy, Parkinson's disease, vascular dementia) * Unable to read or write the patient information letter and broad consent file * Patients who have a life expectancy of less than two years due to a pre-existing condition e.g. cancer