A novel index in healthy infants and children - subarachnoid space: ventricle ratio.

BACKGROUND The subarachnoid space (SAS) and ventricular width (VW) in normal infants and children were studied with ultrasonography to provide the objective measurement and define a normal range for these measurements. The additional aim was to determine the stable ratio as a SAS/VW. MATERIALS AND METHODS A total of 100 healthy subjects, including 48 males and 52 females, were studied. The cases were divided into 3 age groups: 0-6 months(n = 65), 7-12 months (n = 24) and > 13 months (n = 11). Transfontanel ultrasonography was performed in all the cases. SAS, VW and the SAS/VW ratios were calculated. The study was approved by the ethical committee. All parents were informed about the sonographic examination and their approvals were taken. RESULTS SAS was calculated as 3.1 (0.5-6) mm and VW was calculated as 3.6(1.3-5) mm. SAS/VW ratio was 0.9 ± 0.3. There was no statistically significant difference among SAS, VW and SAS/VW ratios in 3-97 percentile group (p > 0.05). CONCLUSIONS Ultrasonography can be used as a practicable and reproducible modality in the measurement of SAS and VW in healthy children. It is a non-invasive method and allows for serial follow-up. SAS/VW ratio can be used as an index in healthy children.