MRI findings in IIH

While imaging is performed to assess for secondary causes of intracranial hypertension, there are several imaging findings that can be seen with IIH.

Patients with IIH should get imaging to rule out secondary causes of elevated intracranial pressure, including MR imaging and MR venographySimilar to an MRI – pictures are taken of the brain using magnets and radiofrequency. During the MRV though, additional pictures are taken to look… of the brain. While imaging is performed to assess for secondary causes of intracranial hypertension, there are several imaging findings that can be seen with IIH. A partially empty sella turcica is a typical feature in the setting of IIH, which appears as a flattened pituitary glandAlso known as the “master gland” it is the area of the brain that manages and makes a large portion of your hormones. within an expanded sella secondary to chronically increased ICPincreased intracranial pressure (Fig 1).

Additionally, slit-like or small compressed ventricles can be seen, typically involving the lateral ventricles (Fig 2).

Another set of imaging findings in the setting of IIH is related to the orbits and includes posterior globe flattening, as well as dilatation of the optic nerve sheaths (Fig 3). The optic nerve sheath dilatation appears as increased CSFFluid that is made by specialized cells in the ventricles of the brain. volume surrounding the intra-orbital optic nerve within the nerve sheath, which can also end up appearing tortuous.

With the use of MR venographySimilar to an MRI – pictures are taken of the brain using magnets and radiofrequency. During the MRV though, additional pictures are taken to look…, a specialized MR technique that allows non-invasive assessment of the flow within the cranial veins, the major intracranial dural venous sinuses can be well evaluated.

Relatively symmetric dural venous sinus stenosis/narrowing at the transverse and/or sigmoid venous sinuses along the posterior fossa of the intracranial compartment is a classic finding in IIH (Fig 4). An underdeveloped transverse sinus with stenosis of the dominant one can also be found. IIH without any stenosis of the venous sinuses is rare.

In the setting of IIH, the elevated ICPincreased intracranial pressure can contribute to prominent arachnoid granulations, also known as Pacchionian granulations, which are projections of the arachnoid membrane into the dural venous sinuses to allow drainage of CSFFluid that is made by specialized cells in the ventricles of the brain. from the subarachnoid space into the venous system. The prominent arachnoid granulations typically occur along the greater wing of the sphenoid bone and can enlarge to become associated with cephaloceles (Fig 5), which are outward herniations of central nervous system (CNS) contents through a defect in the cranium.

The temporal bone at the skull base is another common location for the development of prominent arachnoid granulations and cephaloceles (Fig 6). Prominent arachnoid granulations can rarely also be associated with CSF leaks through the skull base, for which patients may present with clear rhinorrhea or otorrhea.

Dr. Andrew Kim and Dr. John Tsiouris

Dr. Andrew Y. Kim, M.D., is a Neuroradiologist and an Assistant Professor of Radiology at Weill Cornell Medicine. Dr. John Tsiouris, M.D. is the Chief of the Division of Neuroradiology. He is an Associate Professor of Clinical Radiology at Weill Cornell Medical College and an Associate Attending Radiologist at the NewYork-Presbyterian Hospital-Weill Cornell Campus.

All Articles >