Ultrasonic evaluation of jugular venous valve competence.

Jugular venous valve competence has been studied in the past only by invasive venography. The authors demonstrate that this valve can be noninvasively studied using real-time and pulsed Doppler ultrasound techniques and relate this to possible clinical implications. Visualization of the jugular valve with real-time ultrasound is reported and its competence documented using pulsed Doppler and M-mode techniques. The clinical relevance to the etiology of the respirator brain syndrome is discussed.