Is Bigger Always Bad ? Evaluating Effect of Sedation on MRI-Based Optic Nerve Sheath Diameter Measurements in Children

Objectives To assess the impact of sedation on optic nerve sheath diameter (ONSD) as measured by MRI in pediatric patients. ONSD is a widely accepted non-invasive marker for estimating raised intracranial pressure (ICP), but potential effects of sedation on its accuracy remain understudied in children. Materials and Methods A retrospective observational study was conducted on brain MRI scans from pediatric patients aged 0–18 years. Patients were divided into two groups: those who received sedation and those who underwent MRI without sedation. Bilateral ONSD was measured at a standardized point 3 mm posterior to the globe on axial T2-weighted images. Inter-observer agreement was analyzed, and group comparisons used non-parametric statistical methods. Results Out of 78 pediatric patients, 38 received mild sedation and 40 were imaged without sedation. The mean ONSD in the non-sedated group was 4.8 ± 0.3 mm compared to 5.7 ± 0.4 mm in the non-sedated group (p = 0.02). This difference was statistically significant(t(68.5) = -11.2, p <