What are the recommended imaging studies for suspected intracranial hypertension?

Recommended Imaging Studies for Suspected Intracranial Hypertension

For suspected intracranial hypertension, MRI head without and with IV contrast is the most useful initial imaging study, followed by MRI complete spine without IV contrast to evaluate for potential CSF leak sources.1

Initial Imaging Approach

Brain Imaging

1. MRI head without and with IV contrast

   • Most useful for initial evaluation
   • Detects key diagnostic features:
     • Qualitative signs: engorgement of venous sinuses, pachymeningeal enhancement, midbrain descent, superficial siderosis, subdural hygroma/hematoma, convex superior pituitary surface
     • Quantitative signs: pituitary height, pontomesencephalic angle, suprasellar cistern dimensions, prepontine cistern, midbrain descent, venous-hinge angle, mamillopontine angle, tonsillar descent, area cavum veli interpositi1

2. Alternative: MRI head without IV contrast

   • Can be useful if contrast is contraindicated
   • Can still evaluate many features such as midbrain descent, superficial siderosis, subdural collections, and pituitary morphology1
   • Less sensitive than contrast-enhanced studies

Spine Imaging

1. MRI complete spine without IV contrast
   • Optimized with fluid-sensitive sequences
   • Particularly valuable with 3-D T2-weighted fat-saturated sequences
   • Detects epidural fluid collections and meningeal diverticula
   • Helps identify potential CSF leak sources1

Clinical Context Considerations

Spontaneous Intracranial Hypotension

• For orthostatic headache without recent spinal intervention:
  • Both brain and spine imaging are required
  • The cumulative presence of intracranial findings correlates with likelihood of finding a spinal leak source1

Post-Dural Puncture

• For orthostatic headache within 72 hours of dural puncture:
  • Imaging typically not warranted initially
  • Conservative management is first-line approach
  • For persistent symptoms beyond 72 hours, epidural blood patch is typically the next step rather than imaging1

Severe Presentation with Obtundation

• For patients with altered mental status and suspected intracranial hypotension:
  • Expedited imaging with both brain and spine MRI is indicated
  • Helps guide urgent management decisions1

Important Considerations

• CT head is not recommended as the initial imaging study for suspected intracranial hypertension, as it lacks sensitivity for many of the key diagnostic features1
• Avoid unnecessary lumbar puncture for initial evaluation, as MRI can detect epidural collections with equal sensitivity to CT myelography without the risks of LP1
• Advanced imaging techniques such as dynamic CT myelography or digital subtraction myelography are reserved for subsequent evaluation if initial imaging is inconclusive but clinical suspicion remains high1

Pitfalls to Avoid

• False negatives: Approximately 20% of initial brain MRIs and 46-67% of initial spine imaging may appear normal in patients with clinically suspected intracranial hypotension1
• Premature termination of workup: Negative initial imaging should not preclude continued diagnostic evaluation if clinical suspicion remains high
• Delayed diagnosis: CSF-venous fistulas and slow meningeal diverticular leaks are often subtle findings that may require advanced imaging techniques for detection1

Follow-up Imaging

If initial imaging is negative but clinical suspicion remains high:

• Consider dynamic CT myelography or digital subtraction myelography
• These techniques are particularly valuable for detecting subtle CSF-venous fistulas or slow leaks1