Novel Ultrasound Technique to Evaluate the Superior Segment of the Internal Jugular Vein in Normal Subjects.

A novel ultrasound technique was used to assess the superior segment of the internal jugular vein (IJV) in healthy individuals, evaluating the feasibility of visualizing this vein through the parotid gland and examining positional changes. Eighty-five patients undergoing unrelated carotid ultrasound were included, excluding those with headaches, migraines, or other neurological symptoms. A transducer was placed over the parotid gland, and gray scale images-with and without diameter measurement-and color and spectral Doppler of the IJV were obtained in neutral and head turned contralaterally. Technical feasibility and quantitative measurements with mean values and standard deviations were reported. Significant positional changes were assessed if paired data were available. Successful diameter measurements were obtained in at least one side in 79% to 80% of patients and bilaterally in 75%. Mean diameters were 5.5 cm (right) and 5 cm (left). Velocities were acquired in 82% (unilaterally) and 78% (bilaterally). Mean peak systolic velocities were 42 cm/s (right) and 32 cm/s (left). With head rotation, mean velocities were 46 cm/s (right) and 38 cm/s (left). In patients with paired measurements, velocities increased by over 50% in 19% to 28% of patients (P<0.05 for both sides). There was no significant change in the diameter when the head was turned. Visualization of the superior IJV using a parotid window and evaluation of its diameter and internal velocities are feasible with the head in both neutral position and turned contralaterally.