Correlates of embolic events detected by means of transcranial Doppler in patients with carotid atheroma.
OBJECTIVE
This study identified in patients with carotid plaques the associations of emboli detected by means of transcranial Doppler (TCD) with cerebrovascular 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% stenosis, were imaged on duplex scanning and analyzed echomorphologically in a computer with the gray scale median (GSM). The GSM facilitated the quantitative distinction of dark (low GSM) from bright (high GSM) plaques. Stenosis was assessed with duplex scanning. Emboli were counted on TCD in the ipsilateral middle cerebral artery for half an hour. The brain CT infarction patterns (pattern A: discrete subcortical and cortical; pattern B: hemodynamic, diffuse white matter lesions, basal ganglia infarctions, lacunes) and normal CT and cerebrovascular symptoms on the ipsilateral hemisphere were noted.


RESULTS
Emboli were more frequent in symptomatic (median count, 3) than asymptomatic (median count, 0) hemispheres (Mann-Whitney U test, P =.031) and in hemispheres with pattern A infarction (median count, 3.5) than in hemispheres with pattern B infarction or normal CT (median count, 0; Kruskal-Wallis test, P =.047). The increased embolic count was associated with decreased GSM (Spearman correlation, P =.045, r = -0.22), but not with high degrees of stenosis (Spearman correlation, P =.44, r = 0.086).


CONCLUSIONS
Emboli were more frequent in symptomatic than asymptomatic hemispheres and in CT pattern A harboring hemispheres than in CT pattern B or normal hemispheres. They were more frequent in the presence of low-plaque echodensity, but not in the presence of a high degree of stenosis. These data support the embolic nature of cerebrovascular symptomatology and CT pattern A infarctions.
Tegos
T J
TJ
Irvine Laboratory for Cardiovascular Investigation and Research, Department of Vascular Surgery, St Mary's Hospital, Imperial College of Science, Technology, and Medicine, London, UK. t.tegos@ic.ac.uk
Sabetai
M M
MM
Nicolaides
A N
AN
Robless
P
P
Kalodiki
E
E
Elatrozy
T S
TS
Ramaswami
G
G
Dhanjil
S
S
D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D015588:Observer Variation; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial