Doppler ultrasonography of normal neck veins.

Doppler ultrasonography was used to examine 198 neck-vein systems (67 right, 131 left) in 148 patients. The vessel lumen is usually echo-free: the veins are supple, and the internal jugular and sometimes the subclavian veins can be compressed. The venous confluence is Y-shaped. Blood flow was symmetrical and biphasic in 57% of cases, continuous in 29% of cases, and monophasic in 13% of cases. Blood flow velocity was less than 1 m/s in all cases and varied with respiration and heart rate. Color Doppler allows flow imaging and increases the speed and reliability of the procedure. This investigation is useful for following-up patients with indwelling venous catheters and is the investigation of choice whenever pathology of the neck veins is suspected.