MR Imaging signs suggesting Idiopathic Intracranial Hypertension(IIH) :
1. Posterior scleral flattening.
2. Vertical tortuosity of the optic nerve in sagittal images.
3. Protrusion of the optic nerve at the optic disc.
4. Optic nerve sheath dilatation (>5mm), increased peri-optic nerve CSF.
5. Empty Sella.
6. Transverse Sinus narrowing.
Optic nerve sheath dilatation can be seen in both acute and chronic elevation of intracranial pressure(ICP). Its a more sensitive sign of increased ICP.
Posterior scleral flattening and optic nerve head protrusion has lesser sensitivity, but more specificity.
The vertical tortuosity of the optic nerve is seldom seen in cases of acute intracranial hypertension, and is believed may be evidence of chronically elevated ICP.
References :
1. Clinical Radiology, July 2016. Morphometric MRI changes in intracranial hypertension due to cerebral venous thrombosis: a retrospective imaging study.
