To assess the relationship between cross-sectional area of internal jugular veins and brain volumes in healthy individuals without neurologic disease.

A total of 193 healthy individuals without neurologic disease (63 male and 130 female; age > 20 to < 70 years) received magnetic resonance venography and structural brain magnetic resonance imaging at 3T. The internal jugular vein cross-sectional area was assessed at C2–C3, C4, C5–C6, and C7–T1. Normalized whole brain volume was assessed. Partial correlation analyses were used to determine associations.

There was an inverse relationship between normalized whole brain volume and total internal jugular vein cross-sectional area (C7–T1: males r = –0.346, p = 0.029; females r = –0.301, p = 0.002). After age adjustment, association of normalized whole brain volume and normalized gray matter volume with internal jugular vein cross-sectional area became positive in males (normalized whole brain volume and right internal jugular vein cross-sectional area (C2–C3) changed from r = –0.163 to r = 0.384, p = 0.002), but not in the females.

Sex differences exist in the relationship between brain volume and internal jugular vein cross-sectional area in healthy individuals without neurologic disease.