Association of MRI Findings and Visual Outcome in Idiopathic Intracranial Hypertension

OBJECTIVE. Patients with idiopathic intracranial hypertension (IIH) have elevated intracranial pressure (ICP) without an identifiable cause. The clinical course is variable, resulting in irreversible vision loss in some and a benign course in others. Although MRI findings have been described in IIH, their association with visual outcome has not been evaluated to date. MATERIALS AND METHODS. Forty-six patients with IIH underwent funduscopic evaluation, visual field testing, lumbar puncture with opening pressure (OP) measurement, and MRI. Patients were stratified into the following groups by visual outcome: group 1, no vision loss (n = 28); group 2, some vision loss (n = 10); and group 3, severe vision loss (n = 8). MRI findings in the orbits, pituitary gland, and optic canals and the frequency of skull base cephaloceles and of transverse sinus (TS) stenosis were assessed by a reviewer blinded to the patients' visual outcome. Demographic, clinical, and MRI findings were evaluated for association with visual outcome. RESULTS. Patients in group 3 (worst visual outcome) were significantly younger (p = 0.03) and had higher OP (p = 0.04) than patients in the other groups. There were no significant differences in sex, race, or body mass index. Despite worse visual outcomes and sometimes fulminant vision loss, there were no differences in the frequency of orbital MRI findings or TS stenosis, optic canal diameter, and pituitary appearance among the three groups. Group 3 had significantly lower cephalocele frequency than the other groups (p = 0.04). CONCLUSION. Although MRI findings may suggest elevated ICP and the diagnosis of IIH, they are not predictive of visual outcome in patients with IIH.