Doppler ultrasound in vascular surgery.

Doppler ultrasound was first introduced into the study of arterial and venous disorders in 1966. The devices currently used in clinical practice are continous wave systems which, in their simplest form, are pocket-sized units. Instruments with the capability of distinguishing the direction of flow are also available. The signal may be processed for audio use, or an analogue recording can be made of the Doppler frequency shift. The described clinical information will, in large part, dictate the type of equipment used.