Ultrasonographic assessment of subarachnoid space width in healthy infants aged 0-3 months: normative data and associations with anthropometric parameters.

PURPOSE: The aim of this study was to establish ultrasonography-based reference values for subarachnoid space width and to examine associations between anthropometric Z-scores and these measurements in healthy infants aged 0-3 months.

METHODS

This retrospective cross-sectional study included 125 healthy infants aged 0-3 months who underwent cranial ultrasound examinations. Subarachnoid space dimensions were measured bilaterally at the coronal level of the foramen of Monro, including craniocortical width (CCW), sinocortical width (SCW), and interhemispheric width (IHW). Age, body weight (BW), body height (BH), body mass index (BMI), body surface area (BSA), and head circumference (HC) Z-scores were analyzed for associations with subarachnoid space dimensions. Intraobserver reliability was evaluated using the intraclass correlation coefficient (ICC, two-way mixed-effects model).

RESULTS

Mean values for CCW, SCW, and IHW increased progressively with age. Age was the only variable independently associated with CCW and SCW, while no significant anthropometric associations were found for IHW. Based on the 95th percentile, the proposed upper limits were 3.1 mm for CCW, 3.8 mm for SCW, and 4.2 mm for IHW. ICC values ranged from 0.93 to 0.95, indicating excellent intraobserver agreement.

CONCLUSIONS

This study establishes ultrasonography-based normative data and describes growth-related associations for subarachnoid space width during the first 3 months of life. These findings provide a practical reference for interpreting subarachnoid space dimensions during early infancy.