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Emboli Monitoring

Cerebral emboli are often the cause of transient ischemic attacks (TIA) and stroke. Emboli that break off at remote sites and float downstream often lodge in smaller vessels, causing symptoms and brain infarction. Embolic material can be seen, heard and counted by the Doppler ultrasound as it passes through the bloodstream. Individual arterial segments are monitored periodically for intravascular emboli. The arteries monitored are determined by the level of disease (carotid stenosis, atrial fibrillation, prosthetic cardiac valves, native valve disease) or referrable to the patient's symptoms or CT scan findings.

Monitoring for emboli is also done during invasive procedures, including cardiopulmonary bypass, cerebral angiography and carotid endarterectomy. The detection of emboli can further the understanding of the mechanism of stroke, guide therapies and identify patients at increased risk. Embolus detection also provides a new way to understand the pathophysiology of stroke.

Doppler spectral waveform from the middle cerebral artery with embolus. The embolus is depicted as the bright red marking representing the greater reflectivity of embolic materials when compared to that of the moving red blood cells.	Migration of emboli from a carotid plaque into distal vessels.