What type of imaging is needed for chronic headaches with pulsating sensations triggered by pressure and straining since a 1999 head injury?

MRI Head Without Contrast is the Most Appropriate Imaging for Chronic Post-Traumatic Headaches

For chronic headaches with pulsating sensations triggered by pressure and straining since a 1999 head injury, MRI head without contrast is the most appropriate imaging modality, with susceptibility-weighted imaging (SWI) or gradient-recalled echo (GRE) sequences specifically included to detect hemosiderin deposition from prior trauma. 1

Rationale for MRI Selection

• Post-traumatic etiology: The long-standing nature of symptoms (since 1999) with specific triggers (pressure and straining) suggests a post-traumatic headache disorder that requires evaluation of both structural and hemosiderin-related changes.

• Superior sensitivity: MRI is more sensitive than CT for detecting all post-traumatic lesions except skull fractures and subarachnoid hemorrhage, making it ideal for chronic cases 2

• Specific sequence requirements:

  • SWI or GRE sequences are particularly helpful in identifying hemosiderin deposition related to prior remote trauma 1
  • These sequences should be included in the MRI protocol as they are highly sensitive for detecting evidence of previous microhemorrhages 2

Why Not Other Imaging Modalities?

• CT limitations: While CT is the first-line imaging for acute head trauma, it has limited sensitivity for detecting chronic post-traumatic changes 3

• Contrast not indicated: According to ACR guidelines, contrast is typically not useful for evaluating post-traumatic injury unless there is clinical suspicion for an alternative etiology 1

• Advanced imaging techniques: While techniques like MRA might be considered if there is concern for post-traumatic vascular abnormalities (such as aneurysm or arteriovenous fistula), they are not routinely indicated without specific clinical suspicion 1

Clinical Considerations

• Valsalva-triggered symptoms: The pulsating sensations triggered by pressure and straining (Valsalva maneuver) warrant careful evaluation, as this can be a concerning feature requiring prompt imaging 4

• Low yield but necessary: It's important to note that imaging in chronic post-traumatic cases is often low yield but still necessary to exclude significant pathology:

  • One study showed only 1.5% positivity rate for traumatic injury in children after concussion 1
  • Another study demonstrated microhemorrhage in only 0.5% of children with chronic post-traumatic symptoms 1

• Potential findings: MRI may reveal:

  • Areas of microhemorrhage or encephalomalacia related to prior injury 1
  • Structural abnormalities that could explain chronic headaches
  • Alternative etiologies that might require different management

Common Pitfalls to Avoid

• Relying solely on CT: Using only CT when MRI is available and not contraindicated may miss subtle chronic changes 4

• Omitting specialized sequences: Failing to include SWI or GRE sequences would significantly reduce sensitivity for detecting hemosiderin deposition 1, 2

• Overlooking alternative diagnoses: While focusing on post-traumatic etiology, it's important to consider other potential causes of chronic headaches that might be revealed by MRI

By following these evidence-based recommendations, clinicians can appropriately evaluate chronic post-traumatic headaches while optimizing diagnostic yield and patient outcomes.