Clinical and MRI Features in Pediatric Idiopathic Intracranial Hypertension: Focus on Optic Nerve ADC Values

Idiopathic intracranial hypertension (IIH) is defined by increased intracranial pressure (IIP) without pathological findings on neuroimaging. However, several supportive radiological features have been described. This study aimed to define the clinical characteristics of pediatric IIH and to evaluate the effects of IIP on cranial and orbital magnetic resonance imaging (MRI), with a specific focus on apparent diffusion coefficient (ADC) measurements of the optic nerve (ON) using diffusion-weighted imaging (DWI).

Children diagnosed with IIH and healthy controls with available cranial and orbital MRI were included. Data from the past five years were retrospectively analyzed. Cerebrospinal fluid opening pressure (CSF-OP) was measured by pediatric neurologists. Papilledema was graded using the Frisén scale by a neuro-ophthalmologist, and MRI findings were evaluated by a neuroradiologist.

Thirty-six children (F/M: 2/1) were included in the patient group and 40 healthy children (F/M: 29/11) in the control group, with a mean age of 10.8 ± 4.21 years. Fifty-eight percent of the patients were in the postpubertal period. Headache and grade 1 papilledema were the most common findings in patients. The mean CSF-OP was 440 mm CSF. Median ON-ADC values were 1.85 × 10⁻³ (right) and 1.84 × 10⁻³ (left), 3.5% and 6.6% lower, respectively, compared to the control group (right p = 0.32, left p = 0.22). ON sheath diameter, ON tortuosity, and posterior globe flattening were significantly more frequent in patients (p < 0.05).

Although ON-ADC values were lower in children with IIH, the difference was not statistically significant. Larger, prospective studies are needed to explore the relationship between ON microstructure and IIP.