Hemodynamics of the Internal Jugular Vein: An Ultrasonographic Study

Objective: To establish a simple classification of internal jugular venous flow using ultrasonography. Materials and Methods: We retrospectively analyzed the sonographic findings of 1600 consecutive patients who were referred to the neurosono-graphic laboratory. Abnormal jugular venous flow was classified into five groups: (A) markedly decreased flow velocity; (B) stasis and/or thrombus formation; (C) reversed flow; (D) increased turbulent flow; and (E) pulsa-tile turbulent flow. Groups A to C were categorized as slow flow groups and groups D and E as high flow groups. Results: Abnormal jugular venous flow was found in 182 (11%) patients. A slow flow pattern (73%) comprised the majority of abnormalities. Eightynine percent of patients in the slow flow groups had abnormalities in the left internal jugular vein (IJV) and 92% of those in the high flow groups had abnormalities in the bilateral IJV. Incompetence of the jugular valve was the most common cause of slow flow in the IJV. Most of the increased turbulent flow was found in patients with hyperthyroidism and in pregnant women. Arteriovenous malformation and carotid-cavernous fistula were the causes of pulsatile turbulent jugular venous flow. Associated clinical symptoms occurred in only two (1.5%) patients (with a concomitant left IJV and left subclavian vein thrombosis) in the slow flow groups, and in 34 (68%) patients in the high flow groups. Conclusion: Most of the abnormally decreased jugular venous flow occurred on the left side. Decreased venous flow or even thrombosis of one side of the IJV was usually asymptomatic. Increased jugular flow was associated with a physiological hyperemic state in cerebral hemodynamics. Increased awareness and angiographic studies are indicated in patients with pulsatile turbulent jugular venous flow because of a high correlation with intracranial arteriovenous shunting.