Cerebral ischemia induced by compression tests during transcranial Doppler sonography.

Compression tests performed during transcranial Doppler sonography are intended for support in identifying vessels and measuring collateral circulation within the circle of Willis. The resulting information is thought to be valuable in patients with extracranial carotid stenoses, especially for planning carotid and extra-/intracranial bypass surgery. In a retrospective analysis of a series of 380 cases, two patients with symptomatic carotid artery stenoses suffered three compression-induced focal cerebral ischemias. In two instances, these ischemias started under compression. The resulting deficits were reversible. One patient developed an additional and persisting motor deficit whose onset was delayed. The diagnostic benefit of compression tests is not established nor its risk well defined. They should not be used routinely.