Correlates of embolic events detected by means of transcranial Doppler in patients with carotid atheroma

Purpose: This study identified in patients with carotid plaques the associa tions of emboli detected by means of transcranial Doppler (TCD) with cerebr ovascular symptoms, brain computed tomography (CT) infarction patterns, and the attributes of plaques (echodensity, degree of stenosis). Methods: Eighty carotid plaques (in 59 patients), producing 50% to 99% sten osis, were imaged on duplex scanning and analyzed echomorphologically in a computer with the gray scale median (GSM). The GSM facilitated the quantita tive distinction of dark (low GSM) from bright (high GSM) plaques. Stenosis was assessed with duplex scanning. Emboli were counted on TCD in the ipsil ateral middle cerebral artery for half an hour. The brain CT infarction pat terns (pattern A: discrete subcortical and cortical; pattern B: hemodynamic , diffuse white matter lesions, basal ganglia infarctions, lacunes) and nor mal CT and cerebrovascular symptoms on the ipsilateral hemisphere were note d. Results: Emboli were more frequent in symptomatic (median count, 3) than as ymptomatic (median count, 0) hemispheres (Mann-Whitney U test, P = .031) an d in hemispheres with pattern A infarction (median count, 3.5) than in hemi spheres with pattern B infarction or normal CT (median count, 0; Kruskal-Wa llis test, P = .047). The increased embolic count was associated with decre ased GSM (Spearman correlation, P = .045, r = -0.22), but not with high deg rees of stenosis (Spearman correlation, P = .44, r = 0.086). Conclusion: Emboli were more frequent in symptomatic than asymptomatic hemi spheres and in CT pattern A harboring hemispheres than in CT pattern B or n ormal hemispheres. They were more frequent in the presence of low-plaque ec hodensity, but not in the presence of a high degree of stenosis. These data support the embolic nature of cerebrovascular symptomatology and CT patter n A infarctions.