Atherosclerotic plaque at the arch of the aorta has been identified as a potential source for atheroembolic stroke. Imaging of aortic arch plaque can be performed with transesophageal echocardiography (TEE), but TEE is an invasive procedure. A new noninvasive method has been developed to image aortic arch plaque employing transcutaneous real time B-mode ultrasonography with color flow duplex Doppler. B-mode imaging has an 86% accuracy for identifying complex aortic arch plaques as compared with TEE. Noninvasive imaging of the aortic arch can be employed in diagnosing the etiology of cerebrovascular disease in patients with stroke or transient ischemic attack in conjunction with duplex B-mode sonography of the extracranial carotid arteries. It also provides a noninvasive method for studying atherosclerotic plaque in the aortic arch which is applicable for investigational studies of the mechanisms of atherosclerosis and evaluation of pharmacological agents designed to treat atherosclerotic disease.