[Transient ischemic attack due to thoracic aortic dissection: report of a case].

We report a case of a 73-year-old woman with transient left hemiparesis and dysarthria. Neurological signs and symptoms gradually improved over a period of 30 minutes. Carotid sonography revealed common carotid artery (CCA) stenosis and mobile flap at the origin of CCA. On thoracic computed tomography the patient was shown to have dissection of De Bakey type I. She was diagnosed as having a transient ischemic attack due to aortic dissection. Furthermore, it was suggested that the embolic mechanism had occurred from the CCA flap. After replacing the aortic arch, both CCA stenosis and flap had disappeared on carotid sonography. Carotid sonography was useful not only for diagnosis of aortic and common carotid dissections, but also because it contributed to speculation concerning its mechanism and suggesting its relation to ischemic stroke.