A pilot study of microembolic signals in patients with middle cerebral artery stenosis

Objective. There has been limited data on the frequency of microembolic sig nals in patients with middle cerebral artery (MCA) stenosis, especially dur ing the acute phase of stroke. Using transcranial Doppler, the authors pros pectively monitored the MCA segments distal to stenosis in 4 groups of pati ents for 30 minutes: (1) symptomatic patients with acute ischemic stroke an d MCA stenosis, (2) asymptomatic group patients with asymptomatic MCA steno sis, (3) control patients with acute ischemic stroke of undetermined etiolo gy, and (4) normal people. A total of 60 patients completed the study. Ther e were no microembolic signals in the asymptomatic. control, and normal gro ups. Among 20 patients in the symptomatic group, microembolic signals were detected in 3 patients (15%). The number of emboli ranged from 1 to 6 per 3 0 minutes. This is the first report of the presence of microembolic signals in acute stroke patients with MCA stenosis.