• stroke or other cerebrovascular symptom (e.g. TIA) [ Time Frame: 18 month mean follow-up at 6 month intervals ] [ Designated as safety issue: No ]
  

• any cardiovascular event (e.g. MI) [ Time Frame: 18 month mean follow-up at 6 month intervals ] [ Designated as safety issue: No ]
  

Carotid artery disease (atherosclerosis) is a major cause of stroke that can be treated with carotid endarterectomy surgery (CEA) or stenting. Subjects with moderate, asymptomatic stenosis (50-79% narrowing) typically do not undergo intervention because the procedural risks outweigh the benefits. However, some of these individuals will have vulnerable plaque that places them at high risk of stroke, but current diagnostic techniques for vulnerable plaque are lacking. Recently, VPDiagnostics developed a new module - SmartRisk - that stratifies risk of stroke for stenotic (50-79% blockage) atherosclerotic plaque. The SmartRisk module uses MRI data to compute a risk assessment from a specific atherosclerotic plaque. A continuous risk value is generated and patients with risk values above a prespecified threshold are at elevated risk for cerebrovascular events arising from carotid artery disease. The purpose of this trial is to determine whether the SmartRisk module is effective at stratifying risk of a carotid-related cerebrovascular event in subjects with asymptomatic 50-79% carotid stenosis.