Measurement of the normal ventricular system and supratentorial subarachnoid space in children with computed tomography.

The normal ventricular system and subarachnoid space were evaluated on the CT scans of 155 children chosen from 1,400 pediatric CT examinations, and linear measurements were made. The left septum-caudate distance was greater than the right, and the width of the left anterior horn and size of the skull were larger in boys. The interhemispheric and sylvian fissures, the third ventricle and Evans' ratio were larger in the younger group (less than 3 years) than in the older (greater than or equal to 3 years), while the opposite was found for the cella media index and size of the skull. The size of the lateral ventricles (expressed by anterior horn width, septum-caudate distance and width of cella media) was not different in the two age groups of children. Normal limits for the linear measurements and indices are given in Table 2.