The role of sonographic optic nerve sheath diameter measurements in pediatric head trauma.

Abstract

To determine the accuracy of bedside sonographic measurements of optic nerve sheath diameter (ONSD) and ONSD/eyeball transverse (ETD) diameter ratios to predict space-occupying lesions (SOLs) or elevated intracranial pressure (ICP) in pediatric head trauma. Children who presented to the emergency department with head trauma and underwent cranial computed tomography (CT) were enrolled and examined by ocular ultrasonography (US), and the ONSD was measured at 3mm posterior to the globe and ETD were measured. Ratios of ONSD at 3mm/ETD were calculated. All ONSD measurements and ratios were calculated from cranial CT images. Subjects with elevated ICP had increased ONSD measurements and ratios. To predict elevated ICP, the AUC for ONSD at 3mm was 0.956 (95% CI 0.896-1). At a cut-off level of 5.1mm, the sensitivity and specificity of ONSD 3mm values for elevated ICP were 92.9% and 94.0%. For the ONSD 3mm/ETD ratio, it was 0.980 (95% CI 0.959-1). At a cut-off level of 0.22, the sensitivity and specificity were 100% sensitivity and 88.0%. All sonographic ONSD measurements and ratios were significantly correlated with readings calculated from cranial CT images. Sonographic ONSD measurements and ratios were found to be quite sensitive to detect elevated ICP on cranial CT images. Additionally, there was a significant correlation between measurements calculated by ocular US and cranial CT scans. Bedside ocular US seems to be a promising and useful tool to determine ICP in children with head trauma.