MRI and ultrasonographic findings in idiopathic intracranial hypertension

A 29-year-old obese man presented with bilateral blurred vision and headache. Cerebrospinal fluid (CSF) opening pressure was 310 mmH₂O with normal composition. Magnetic resonance imaging (MRI) revealed an empty sella, buckling of the optic nerve, and prominent bilateral perioptic cerebrospinal fluid spaces (Figure 1). Ultrasound examination showed bilateral optic nerve sheath dilatation (Figure 2). The optic nerve sheath diameter (normal: 5.21 ± 0.43 mm in our hospital) increases almost to greater than 5.8 mm if significantly raised intracranial pressure is present (1).

Figure 1.

Magnetic resonance imaging (MRI) features of idiopathic intracranial hypertension. (A, B) Axial T2-weighted MR images showing buckling of the bilateral optic nerves. (C, D) Sagittal T2-weighted MR images showing partially empty sella turcica and buckling of the optic nerves.

Figure 2.

Optic nerve sonographic features of idiopathic intracranial hypertension. The bilateral optic nerve sheath diameter is significantly enlarged. The optic nerve sheath is 6.8 mm in diameter for the right eye and 6.6 mm for the left eye.

Unlike other invasive methods, sonographic assessment of the diameter of the optic nerve sheath for detecting raised intracranial pressure has been shown to be feasible, non-invasive, and rapidly carried out (2).