Schiersmann index is used to assess ventricle size with respect to brain tissue.
Parameters:
(1) maximum biparietal diameter of the skull
(2) distance between thecella media (bodies of the lateral ventricles) in the same slice
index =
= (maximum external diameter) / (cella media distance)
|
Age
|
Normal Mean (Wilk et al)
|
|
<= 12 months
|
3.978
|
|
1.01 to 3 years
|
4.413
|
|
3.01 to 6 years
|
5.011
|
|
6.01 to 9 years
|
4.548
|
|
9.01 to 12 years
|
4.668
|
|
12.01 to 15 years
|
4.719
|
|
15.01 to 18 years
|
4.803
|
Interpretation:
• With hydrocephalus and cerebral atrophy the cella media distance increases, reducing the ratio.
