Microembolus detection via transcranial Doppler sonography

Clinically silent cerebral circulating microemboli are noninvasively detect able by transcranial Doppler sonography (TCD) leading to a characteristic t ransient increase in the frequency spectrum. These TCD signals are now Know n as "Microembolic Signals" (MES) or "High Intensity Transient Signals" (HI TS). Experimental studies have shown that the acoustic properties of MES ar e determined by size and structural composition of the circulating microemb oli. Overwhelming evidence exists that these MES possess clinical relevance enabling the assessment of the actual thromboembolic activity on an indivi dual basis. This allowed for obtaining new etiologic and prognostic informa tion in various patient groups suffering from, or at risk of, ischemic stro kes. The recent introduction of sophisticated MES detection software and th e validation of multichannel TCD monitoring has considerably improved the m onitoring procedure and its diagnostic confidence as well. TCD detection of MES represents a promising novel technique to refine the prevention and th erapy of cerebrovascular diseases on a more individual basis.