Transcranial Doppler characteristics of different embolic materials during in vivo testing.

Purpose: The authors investigated whether ultrasonic characteristics of embolic signals could be used to differentiate embolic composition.

Materials And Methods: The authors analyzed high-intensity transient signals (HITS) from 3 patients with patent foramen ovale during the bubble contrast test and during total joint replacement surgery. In 3 anesthetized dogs, latex microspheres, fat particles, and air bubbles were injected into the internal carotid artery and HITS were identified in the cerebral circulation.