Change in optic nerve sheath diameter as a radiological marker of outcome from endoscopic third ventriculostomy in children.

Abstract

The purpose of this study was to investigate the value of the change in optic nerve sheath diameter (ONSD) as a radiological marker of endoscopic third ventriculostomy (ETV) outcome in children. Magnetic resonance imaging (MRI) scans of patients on whom ETVs were performed between the periods of January 2009 and June 2013 were reviewed. ONSD measurements on pre- and post-operative images were performed by two blinded observers, and the relationship between the change in these measurements and outcome from ETV were investigated. These findings were then also compared to conventional imaging features associated with ETV outcome. MRI scans of 24 patients were adequate to measure the ONSD pre- and post-operatively. In patients with successful ETV (n = 19), the mean change in ONSD was 0.73mm and in patients with a failed ETV (n = 5), the mean change in ONSD was 0.18mm (p = 0.0007). A change in ONSD of 7.5% of the initial measurement demonstrated a sensitivity of 92.9% and a sensitivity of 85.7% for ETV outcome (area under the receiver operating characteristic curve (AUROC) = 0.96). Change in ONSD is a useful radiological marker of ETV outcome and may be used in combination with conventional radiological parameters to aid decision-making in this difficult group of patients.