Clusters of microembolic signals: a new form of cerebral microembolism presentation in a patient with middle cerebral artery stenosis.

Abstract

Middle cerebral artery (MCA) stenosis is a rare occlusive disease in western populations, with a high risk of stroke recurrence. An artery-to-artery embolic mechanism has been argued. We report the detection of a new pattern of microembolic signals (MES) in the MCA poststenotic segment in a patient with multiple recurrent transient ischemic attacks. A 75-year-old man was admitted to our hospital with a transient leg monoparesis on the left side. Right MCA stenosis was detected by transcranial Doppler ultrasonography (TCD). In spite of aspirin treatment, the patient had a recurrent right hemispheric transient ischemic attack, and anticoagulant therapy was started. A new, similar event happened after correct anticoagulation. The bigated TCD monitoring study of both MCAs disclosed clusters of MES at the poststenotic MCA segment. Each cluster contained between 12 and 45 embolic signals. The patient became asymptomatic and clusters of MES disappeared, coinciding with the combination of ticlopidine and oral anticoagulants. We describe a new presentation of MES, ie, grouped in clusters of signals, that may be associated with a high risk of stroke recurrence.