Regional Perivascular Space Burden in Pediatric Idiopathic Intracranial Hypertension: A Case-Control MRI Study

Background/Objectives: Altered perivascular fluid dynamics and glymphatic function have been implicated in the pathophysiology of idiopathic intracranial hypertension (IIH), but data in pediatric patients remain limited. Our aim was to evaluate MRI-visible perivascular space (PVS) burden in pediatric IIH and investigate its relationship with conventional MRI findings, transverse sinus stenosis (TSS), and cerebrospinal fluid (CSF) opening pressure. Methods: In this retrospective case-control MRI study, 46 pediatric patients with clinically confirmed IIH and 46 controls frequency-matched by age and sex were included. PVS burden was independently assessed by two pediatric radiologists on axial T2-weighted images using the Potter grading system. Conventional MRI findings associated with IIH and TSS were evaluated. Associations between PVS burden, TSS, and CSF opening pressure were analyzed. Interobserver agreement was assessed using Cohen's kappa statistics. Results: Basal ganglia PVS scores were significantly higher in pediatric IIH patients than in controls (p = 0.005), while no significant differences were observed in centrum semiovale or brainstem PVS scores. Centrum semiovale PVS scores differed according to TSS status; TSS-negative patients had lower scores than both TSS-positive patients and controls (Holm-adjusted p = 0.007 for both comparisons), whereas TSS-positive patients did not differ significantly from controls. No significant correlation was observed between CSF opening pressure and PVS scores in any evaluated region. Interobserver agreement for PVS grading was good for the centrum semiovale and basal ganglia and moderate for the brainstem. Conclusions: Pediatric IIH was associated with increased basal ganglia PVS burden, suggesting a regionally heterogeneous pattern. Pediatric IIH was associated with increased basal ganglia PVS burden, suggesting a regionally heterogeneous pattern. Centrum semiovale PVS burden differed according to TSS status, with lower scores in TSS-negative patients than in both TSS-positive patients and controls, whereas TSS-positive patients did not differ significantly from controls.