Long-term Neurocognitive Sequelae of Subclinical Microembolization During Carotid Interventions

Inclusion Criteria: * Patient is male or female \>40 yrs of age. * Patient has occlusive extracranial carotid stenosis (≥70%) * Patient is scheduled to undergo an endovascular intervention of a lesion in the extracranial carotid artery * Patient agrees to voluntarily participate and signs an informed consent. * Patient agrees to be available for follow-up and is able to participate in all study testing procedures. * Patient has sufficient visual and auditory acuity for cognitive testing. Exclusion Criteria: * Patient is unable to safely and comfortably undergo magnetic resonance imaging procedures (e.g., claustrophobia, implanted medical devices that are MRI incompatible such as pacemaker, defibrillator, neural stimulator etc) * Patient has an untreated or unsuccessfully controlled psychiatric disease (schizophrenia, bipolar disorder). * Patient has prominent suicidal or homicidal ideation. * Patient has acute illness or unstable chronic illness (e.g. uncontrolled hypertension, hepatic encephalopathy, portal hypertension, ascites, and esophageal varices, pancreatitis). * Patient with a history of neurological (e.g., multiple sclerosis, seizure disorder, Parkinson's disease) or systemic illness affecting central nervous system function. * Patient has prior closed head injury with ≥24 hours of amnesia. * Patient is unable to understand or sign the informed consent.