RELATIONSHIP OF COMMON CAROTID-ARTERY HIGH-INTENSITY TRANSIENT SIGNALS IN PATIENTS WITH ISCHEMIC STROKE TO WHITE-MATTER VERSUS TERRITORIAL INFARCT PATTERN ON BRAIN CT SCAN

The understanding of the ischemic mechanism in the individual stroke p atient remains problematic. Cranial computed tomography (CCT) and magn etic resonance imaging (MRI) of the brain have improved the ability to identify and localize the infarct, and the pattern of infarction has been related to the presumed ischemic mechanism. But without in vivo m ethods to identify actual cerebral emoblization, the diagnosis of cere bral emoblism or any assumptions regarding infarct pattern must still be based on circumstantial evidence (identifying the 'smoking guns'). Doppler monitoring for high intensity transient signals (HITS) now all ows the detection of cerebral embolization in specific patients, and m ight increase the understanding of the relationship between cerebral e mbolism and specific patterns of infarction on CCT or MRI. We performe d Doppler monitoring for HITS in the common carotid arteries (CCA) of 56 patients admitted for ischemic stroke, who also had CCT studies. CC T lesions were classified as lacunar, territorial, borderzone, leuko-a raiosis or no identifiable lesion. The relationship to CCA HITS was ev aluated with Fisher's exact test. HITS were detected in 10 of 56 patie nts (17.9%), and territorial infarct was the most frequent pattern see n in those with HITS (9/10), but this relationship did not quite reach statistical significance (p = 0.09). However, HITS were more prevalen t in territorial than in lacunar strokes, or a combination of lacunar infarcts and leuko-araiosis (p < 0.0001 and p < 0.006, respectively). This study provides in vivo support for the notion that lacunes are ra rely due to cardioembolism, and that such events usually result in ter ritorial infarcts. This method may be more precise than clinical asses sment alone for identifying cerebral embolization in specific patients , as well as evaluating which potential causes for stroke are actually active.