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.