MICROEMBOLI ON TRANSCRANIAL DOPPLER IN PATIENTS WITH SPONTANEOUS CAROTID-ARTERY DISSECTION

High-intensity transient signals on transcranial Doppler sonography (T CD) are associated with atherosclerotic stenosis of the internal carot id artery. Few data exist regarding the detection of high-intensity tr ansient signals in dissected carotid arteries. In the present study, 6 patients with spontaneous carotid dissection, defined by magnetic res onance techniques and duplex sonography, were examined by TCD. Both mi ddle cerebral arteries were monitored simultaneously for 30 minutes. F our of the patients had ipsilateral cerebral ischemia, while 2 present ed with other symptoms. High-intensity transient signals were detected in the middle cerebral artery ipsilateral to the dissection in 3 of t he 4 patients with cerebral ischemia and in none of the patients with other presenting symptoms. No microemboli were found contralateral to the dissected arteries. Microemboli can be detected distally from diss ected carotid arteries. The present findings support the assumption th at embolism is a major cause of stroke in patients with carotid dissec tion, and suggest that high-intensity transient signals are more commo n among patients with cerebral ischemia secondary to dissection.