Internal jugular venous flow measurement by means of a duplex scanner.

Using a special probe holder, cross-sectional area and time-averaged mean spatial velocity of the internal jugular vein were measured by means of a duplex scanner and multiplied to calculate volume flow. In a cohort of 100 subjects ages 21 to 70 years, average right plus left flow was 740 +/- 209 mL/min. Flow was 8.7% lower in females than in males. Normalization of flow to 100 g brain tissue by dividing it through the mean sex specific brain weight resulted in no significant sex difference. Within the age range investigated, there was no decrease of flow with age.