Atherosclerotic plaque at the carotid artery bifurcation is a major source of stroke. The purpose of this investigation is to determine the ability of the SmartRisk software module to predict stroke or stroke-related events due to carotid plaque within a high-risk population. The SmartRisk software module operates on magnetic resonance images (MRI) of the carotid artery wall.

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.

Inclusion Criteria:

• 50-79% stenosis of the carotid artery
• age 18 or older
• no ischemic neurovascular symptoms within preceding 6 months

Exclusion Criteria:

• contraindication to MRI (e.g. weight > 130 kg, pregnancy)
• prior or planned carotid endarterectomy or stenting
• history of atrial fibrillation
• prior neck irradiation

Patient referred for ultrasound assessment of carotid artery disease