Evaluating Raised Intracranial Pressure Using MR Elastography

Investigators will compare magnetic resonance (MR) elastography measurements to other forms of noninvasive methods of detecting raised intracranial pressure, including optical coherence tomography (OCT) imaging measurements of the retinal nerve fiber layer (RNFL) and indirect signs of raised intracranial pressure on magnetic resonance imaging (MRI).

The goal of this study is to evaluate the brain elasticity in patients with idiopathic intracranial hypertension (IIH) and other forms of raised intracranial pressure, such as obstructive hydrocephalus. Investigators will evaluate for a correlation between brain stiffness and opening pressure on lumbar puncture. Investigators will also evaluate for changes in brain stiffness after interventions that are aimed at lowering intracranial pressure, including lumbar punctures, medications, and surgical interventions, such as ventriculoperitoneal shunts. Lastly, investigators will compare MR elastography measurements to other forms of noninvasive methods of detecting raised intracranial pressure, including optical coherence tomography (OCT) measurements of the retinal nerve fiber layer (RNFL) and indirect signs of raised intracranial pressure on MRI.

Patients will receive the MR elastography, MRI structural brain imaging, Optical Coherence Tomography (OCT) imaging, Optic nerve B-scan ultrasound and Lumbar puncture.

Patients will receive the MR elastography, MRI structural brain imaging, Optical Coherence Tomography (OCT) imaging, and Optic nerve B-scan ultrasound. Some patients will receive lumbar punctures.

MR elastography image acquisition will be conducted on the Compact 3T MRI scanner using a modified single-shot spin-echo echo-planar imaging pulse sequence.

All patients with papilledema will get lumbar punctures with opening pressure as part of their work-up for papilledema. A small number of patients without increased intracranial pressure will receive a lumbar puncture.

Optical Coherence Tomography (OCT) imaging will measure the peripapillary retinal nerve fiber layer (RNFL) thickness measurements The images with enhanced depth imaging will be obtained to measure the Bruch's membrane orientation.

Ultrasound will be used to measure the optic nerve sheath diameter 3 mm posterior to the posterior scleral surface.

The primary outcome measure is the difference in the brain elasticity on MR elastography between patients with raised intracranial pressure and those with normal intracranial pressure

The secondary outcome measurement are the retinal nerve fiber layer (RNFL) thickness and Bruch's membrane configuration on the MRI findings of raised intracranial pressure (optic nerve sheath diameter and pituitary/sella ratio). The cutoff from abnormal-to-normal will be established. The sensitivity and specificities will be established and compared against the other secondary outcome measurements and against MR elastography.

The secondary outcome measurements are the retinal nerve fiber layer (RNFL) thickness and Bruch's membrane configuration using ocular coherence tomography (OCT) of raised intracranial pressure (optic nerve sheath diameter and pituitary/sella ratio). The cutoff from abnormal-to-normal will be established. The sensitivity and specificities will be established and compared against the other secondary outcome measurements and against MR elastography

The secondary outcome measurement are the retinal nerve fiber layer (RNFL) thickness and Bruch's membrane configuration on the optic nerve B-scan ultrasound findings of raised intracranial pressure (optic nerve sheath diameter and pituitary/sella ratio). The cutoff from abnormal-to-normal will be established. The sensitivity and specificities will be established and compared against the other secondary outcome measurements and against MR elastography.

All subjects will have the following inclusion criteria: Group 1: Papilledema from idiopathic intracranial hypertension and other forms of elevated intracranial pressure, including obstructive hydrocephalus Group 2: Patients without raised intracranial pressure. All subjects will have the following exclusion criteria: Age <18 Pregnancy (self-reported) Individuals for whom MR is contraindicated