CLINICAL CORRELATES OF HIGH-INTENSITY TRANSIENT SIGNALS DETECTED ON TRANSCRANIAL DOPPLER SONOGRAPHY IN PATIENTS WITH CEREBROVASCULAR-DISEASE

Background and Purpose High-intensity transient signals detected by tr anscranial Doppler sonography have been associated with particulate ce rebral emboli. Their clinical correlates are poorly understood. This s tudy was undertaken to assess their relation to cerebral ischemia and to determine whether the severity of cerebral arterial stenosis has an impact on their occurrence. Methods We studied 96 arteries in 75 cons ecutive patients with extracranial or intracranial arterial lesions or potential cardiac sources of cerebral embolism. Sixty patients had hi stories of cerebral or retinal transient ischemic attacks or infarcts, and 15 were asymptomatic. The diagnosis of ischemia was based on the clinical presentation and was supported by extensive laboratory testin g. A transcranial Doppler sonography unit equipped with special softwa re for emboli detection was used. Signals were selected based on crite ria established a priori. Results Signals were detected in the territo ries of 28.3% of symptomatic and 11.6% of asymptomatic arteries. The d ifference was significant (P=.045). When patients with suspected cardi ac embolic sources were excluded, the difference between symptomatic ( 27.9%) and asymptomatic (2.9%) arteries remained significant (P=.003), and signals were more frequent distal to arteries with more than 50% area stenosis (23.5%) than arteries with stenoses equal to or less tha n 50% (3.7%) (P=.028). In patients with only extracranial internal car otid artery stenoses, the difference between these degrees of stenosis remained significant (P=.043). Conclusions We conclude that high-inte nsity transient signals are significantly more common in the territori es of symptomatic arteries and distal to lesions causing more than 50% stenosis. These findings may have diagnostic and therapeutic applicat ions.