The role of transcranial Doppler sonography in the identification of patients at risk of cerebral and brainstem ischemia.

OBJECTIVE

To review the literature pertaining to transcranial Doppler (TCD) examination of the anterior and posterior cerebral circulation. This paper focuses on the application of TCD as a screening modality for vertebral artery-induced brainstem ischemic events.

DATA SOURCES: A Medline literature search was performed. Key terms included; transcranial Doppler, vertebral artery dissection, neck trauma, stroke and vertebrobasilar system.

DATA EXTRACTION: The studies examined TCD techniques that monitor the hemodynamics of the circle of Willis. Papers pertaining to vertebral artery trauma and resulting brainstem injury were included. The validity and reproducibility of these procedures were also reviewed.

CONCLUSION

TCD procedures provide hemodynamic data pertaining to intra-arterial vertebrobasilar stenosis and extra-arterial mechanical compression of the vertebral arteries. During cervical spine positional testing, brainstem symptoms may be correlated with TCD documented perfusion deficits. TCD increases the sensitivity of the standard positional test.