Objective To investigate the clinical and imaging features and follow-up results of patients with microembolus (MES).Methods A retrospective analysis was performed for the clinical and follow-up data of 10 patients with MES.Results The mean age of the 10 patients was 58±14.09 years. There were 2 female and 8 male patients, with ischemic cerebrovascular events as the main clinical diagnosis. Among these patients, 8 had moderate or severe localized stenosis of the vessels at the MES-positive side; 6 had heterogeneous plaques on neck color Doppler ultrasound; 1 had a medical history of cardiac valve replacement and multiple monitors showed that a large number of MES passed through the middle cerebral artery at both sides, with occlusion of the right internal carotid artery, but the patient did not experience stroke; 3 had positive results of transcranial Doppler ultrasound foaming test without vascular stenosis, among whom 1 had thrombus rain. The patients were followed up at 3 months after surgery, and 1 patient was found to have massive cerebral infarction at the MES-positive side, which caused paralysis and aphasia. The 3 patients with positive results of the foaming test still had positive MES, and there was no significant change in the number of MES passing through the artery during the same period of time. Neck vascular ultrasound showed hyperechoic or isoechoic plaques in cervical vessels in 5 patients and hypoechoic plaques in 1 patient; 6 patients were found to have varying degrees of reduction in cognitive function.Conclusions Positive MES is associated with unstable plaques of intracranial and extracranial arteries or patent foramen ovale. Recurrence of stroke and reduction in cognitive function should be monitored in MES-positive patients.