Microembolic Signals in Patients with Acute Nonembolic Stroke

Background The nature of microembolic signals (MES) in patients without apparent sources of embolism remains elusive. We hypothesize that MES in acute stroke patients without an embolic source may represent a transient phenomenon related to blood rheology or clot dissolving, in which case the characteristics of such MES would differ from those with definitive sources of emboli. Methods We compared the intensity and duration of 250 MES in 62 acute nonembolic stroke patients (stroke group) and 217 MES in 57 patients with asymptomatic carotid stenosis (≥50%; carotid group). Results The duration of MES was significantly different between the 2 groups (24.86 ± 0.89 ms in the carotid group v 18.8 ± 0.83 in the stroke group; P