DETECTION OF EMBOLISM WITH DOPPLER ULTRASOUND - A REVIEW

Doppler detection of venous and arterial gas emboli has been recognize d since 1968. The technology has been applied using 5-MHz ultrasound t o study decompression sickness and monitor cardiopulmonary bypass and intracranial surgery. Since the advent of transcranial Doppler, which requires the use of lower ultrasonic carrier frequencies to penetrate the temporal bone, the detection of particulates moving in the bloodst ream has been available. Using 2 MHz, microembolic signals have been d etected in a variety of clinical situations, including cardiac conditi ons known to have high probabilities to produce embolic stroke. The ba sic features of a Doppler embolic signal have been clarified, and many investigators are applying the technology to determine the clinical s ignificance of the detected emboli and their use in diagnosis and medi cal and surgical treatments. The basis for automatic sizing, counting, and characterizing the emboli is under development. The applications of improvement in surgical techniques and adjustments in medical treat ments.