Table 3 The normal values of CSF flow indices in the aqueduct of Sylvius measured by phase-contrast MRI

Stroke volume

The average of the volume passing distally in systole and proximally in diastole [4, 13]

30 to 50 μl [4, 14]

Net flow

Difference between the integrated CSF inflow and outflow over one cardiac cycle [11]

• 0.41 ± 0.51 ml/m in children less than 2 years of age

• 0.78 ± 0.89 ml/m in older children [11]

Peak velocity

Either maximum velocity or minimum velocity, whichever has the highest absolute value [15]

• 5.28 ± 2.88 cm/s in infants

• 6.57 ± 3.41 cm/s in children

• 4.12 ± 2.07; 7.89 ± 2.57 cm/s in adolescents [10, 12]

Mean velocity

The mean CSF flow velocity [15]

• 0.74 ± 0.90 cm/s in infants

• 0.87 ± 0.69 cm/s in children

• 0.85 ± 0.62 cm/s in adolescents [10]