ABSTRACT
BACKGROUND: Pineal region lesions in children are heterogenous pathologies often symptomatic due to occlusive hydrocephalus and thus elevated intracranial pressure (ICP). MRI-derived parameters to assess hydrocephalus are the optic nerve sheath diameter (ONSD) as a surrogate for ICP and the frontal occipital horn ratio (FOHR), representing ventricle volume. As elevated ICP may not always be associated with clinical signs, the adjunct of ONSD could help decision making in patients undergoing treatment. The goal of this study is to assess the available magnetic resonance imaging (MRI) of patients with pineal region lesions undergoing surgical treatment with respect to pre- and postoperative ONSD and FOHR as an indicator for hydrocephalus. METHODS: Retrospective data analysis was performed in all patients operated for pineal region lesions at a tertiary care center between 2010 and 2023. Only patients with pre- and postoperative MRI were selected for inclusion. Clinical data and ONSD at multiple time points, as well as FOHR were analyzed. Imaging parameter changes were correlated with clinical signs of hydrocephalus before and after surgical treatment. RESULTS: Thirty-three patients with forty operative cases met the inclusion criteria. Age at diagnosis was 10.9 ± 4.6 years (1-17 years). Hydrocephalus was seen in 80% of operative cases preoperatively (n = 32/40). Presence of hydrocephalus was associated with significantly elevated preoperative ONSD (p = 0.006). There was a significant decrease in ONSD immediately (p < 0.001) and at 3 months (p < 0.001) postoperatively. FOHR showed a slightly less pronounced decrease (immediately p = 0.006, 3 months p = 0.003). In patients without hydrocephalus, no significant changes in ONSD were observed (p = 0.369). In 6/6 patients with clinical hydrocephalus treatment failure, ONSD increased, but in 3/6 ONSD was the only discernible MRI change with unchanged FOHR. CONCLUSIONS: ONSD measurements may have utility in evaluating intracranial hypertension due to hydrocephalus in patients with pineal region tumors. ONSD changes appear to have value in assessing hydrocephalus treatment failure.
