MRI Findings in Pseudotumor Cerebri (Idiopathic Intracranial Hypertension)

Key MRI Findings

The American College of Radiology recommends MRI of the brain in pseudotumor cerebri, which typically shows normal brain parenchyma without mass, hydrocephalus, or abnormal meningeal enhancement, but demonstrates specific secondary signs of elevated intracranial pressure including empty sella, posterior globe flattening, optic nerve changes, and enlarged optic nerve sheaths 1, 2
Posterior globe flattening is present in 80% of cases with 56% sensitivity and 100% specificity, according to the American College of Radiology 2
Empty sella or partially empty sella is found in 70% of cases, a hallmark feature of chronically elevated intracranial pressure, as recommended by the American College of Radiology 1, 2
Distension of the perioptic subarachnoid space is detected in 45% of cases, as reported by the American College of Radiology 1
Enlarged optic nerve sheath has a mean diameter of 4.3 mm in IIH patients versus 3.2 mm in controls, according to the American College of Radiology 2
Smaller pituitary gland size has a mean of 3.63 mm in IIH versus 5.05 mm in controls, as recommended by the American College of Radiology 2

The American College of Radiology recommends MRI of the head and orbits as the most useful imaging modality because it provides superior resolution of intracranial and intraorbital structures compared to CT 1, 2
MR venography (MRV) is recommended to demonstrate narrowing of the distal transverse sinuses and exclude cerebral venous sinus thrombosis, as suggested by the American College of Radiology 1, 2

MRI brain with and without contrast is recommended to exclude secondary causes of elevated intracranial pressure, although this guideline is from Praxis Medical Insights, the American College of Radiology also emphasizes the importance of contrast-enhanced MRI 3
Dedicated orbital imaging with coronal, fat-saturated T2-weighted sequences is recommended to evaluate optic nerve sheaths, as suggested by the American College of Radiology, although the specific guideline is from Praxis Medical Insights 4