Measurement of Optic Nerve Sheath Diameter by Computed Tomography in the Pediatric Population: Normal Values

Purpose: To determine the normal values of optic nerve sheath diameter (ONSD) by computed tomogra-phy (CT) in the pediatric population.Methods: The CT scans of pediatric patients aged 1 to 16 years who underwent brain CT for different reasons, who did not have intracranial pathology or increased intracranial pressure, and who had no pathology on CT were included in the study. Four age groups were de-fined with the following ranges: 1 to 2, 3 to 6, 7 to 10, and 11 to 16 years. ONSD was measured from axial CT images, 3 and 10 mm behind the optic globe.Results: The normative values of ONSD measured on CT imaging in children aged 1 to 16 years were reported. The change in ONSD according to age was investigated. ONSD was found to increase with age at both levels measured. The difference was statistically significant. Conclusions: Normal values should be known to de-tect pathologies that may cause an increase in optic nerve diameter. The values reported in this study can serve as a reference for normal optic nerve sheath di-ameter in the pediatric age group.