(Ultrasound Review) Air contrast ultrasonography was used to evaluate jugular valve (IJ)incompetence in a study published in Journal of Ultrasound in Medicine. The IJ veins are the main veins draining blood from the brain to the heart. Valves within the IJ veins are the sole venous valves between the brain and the heart.
"Knowledge of these valves and their noninvasive evaluation might be useful in clinical practice...the absence or incompetence of IJ valves has been associated with neurologic symptoms, because in conditions such as coughing, straining to defecate, the Valsalva maneuver, and chest compression during cardiopulmonary resuscitation, the transmission of intrathoracic pressure to the IJ vein is not counterbalanced," the Italian authors wrote. The resulting venous engorgement might increase intracranial pressure and cause transient brain disturbances, they said.
Researchers at the University of Brescia examined 125 healthy volunteers in order to assess the efficacy of ultrasound in evaluating jugular vein flow. "The aim of this study was to evaluate the prevalence of IJ valves in the general population and to determine whether air contrast ultrasonography is a good method for assessment of the valves, giving adequate information on their presence, morphologic characteristics, location and competence," they said.
Using a high frequency linear array transducer (7.5 MHz) with color Doppler imaging, patients were examined in the supine position with the head slightly turned away from the side being examined.
"The site of investigation of the jugular vein was 1.5-2.0 cm distal to the brachiocephalic vein," they reported. Valves on both sides were visualised before and after the Valsalva maneuver. Injecting a mixture of saline and air into the antecubital veins created air contrast.
The IJ valves were visualised in 96.8% of subjects and were present bilaterally in 85.6% of cases. There were 14 subjects with valves in only one of the IJ veins. Results demonstrated valvular incompetence in 38.4% of subjects with a right-sided prevalence (30.2%). IJ vein incompetence occurred more frequently in patients over 50 years (38.8%) compared with those under 50 years (20%), and was more common in men (25%) compared with women (10.4%).
They concluded "air contrast ultrasonography is a noninvasive method for evaluation IJ valves and identifying retrograde venous flow."
Jugular valve incompetence -- a study using air contrast ultrasonography on a general populationN M Addawi et al
Clinica neurologica II, Spedali Civili, University of Brescia, Brescia, Italy
J Ultrasound Med 2002 July; 21:747-751
By Ultrasound Review
August 19, 2002
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