Risk Assessment of Carotid Plaques Using 3D Contrast-Enhanced Ultrasound

Inclusion Criteria: * Patients \>18 years old and willing and able to participate. Patients with atherosclerosis scheduled for carotid endarterectomy Exclusion Criteria: * • Pregnancy or breast-feeding at the time of the scan * Patients with known hypersensitivity or allergy to any component (including perflutren) of Definity (Lantheus Medical Imaging, Billerica, MA). * Patients who are medically unstable, patients who are seriously or terminally ill, and patients whose clinical course is unpredictable. For example: * Patients on life support or in a critical care unit. * Patients with unstable occlusive disease (e.g., crescendo angina). * Patients with clinically unstable cardiac arrhythmias, such as recurrent ventricular tachycardia. * Patients with uncontrolled congestive heart failure (NYHA Class IV). * Patients with recent cerebral hemorrhage. * Patients who have undergone surgery within 24 hours prior to the study sonographic examination. * Patients with unstable cardiopulmonary conditions (acute myocardial infarction, acute coronary artery syndromes, worsening or unstable congestive heart failure, or serious ventricular arrhythmias) or respiratory distress syndrome. * Patients with uncontrollable emphysema, pulmonary vasculitis, pulmonary hypertension or a history of pulmonary emboli. * Patients who have received any contrast medium (X-ray, MRI, CT or ultrasound) in the 24 hours prior to the research ultrasound exam