MRI Without Contrast for Intractable First-Time Migraine
For an intractable first-time migraine, MRI without contrast is the most appropriate imaging choice when neuroimaging is indicated, with contrast only being added if abnormalities are found on the initial non-contrast study. 1
When Neuroimaging Is Indicated
Neuroimaging is not routinely recommended for typical migraine presentations with normal neurological examinations, as the prevalence of significant intracranial abnormalities in these patients is only approximately 0.2% 1. However, neuroimaging should be considered in the following circumstances:
- Presence of unexplained abnormal findings on neurological examination 1
- Atypical headache features or "red flags" including:
- Headache worsened by Valsalva maneuver 1
- Headache that awakens the patient from sleep 1
- New-onset headache in older patients 1
- Progressively worsening headache 1
- Rapid increase in headache frequency 1
- Thunderclap headache (sudden severe headache) 1
- Focal neurologic signs 2
- Papilledema 2
- Neck stiffness 2
- Immunocompromised state 2
- Personality changes 2
- Headache after trauma 2
- Headache worse with exercise 2
Imaging Modality Selection
MRI Without Contrast
- MRI without contrast is the preferred initial imaging modality for intractable first-time migraine when neuroimaging is indicated 3
- For secondary headaches, MRI head without IV contrast is usually appropriate, with postcontrast imaging only indicated if the noncontrast study shows abnormalities 3
- MRI provides superior characterization of brain tissue and can detect subtle abnormalities that may be missed on CT 1
When to Add Contrast
- Contrast should only be added if abnormalities are found on the initial non-contrast MRI 3
- For headaches attributed to suspected infection, MRI head with and without IV contrast is appropriate 3
When to Consider CT Instead
- In emergency settings with suspected subarachnoid hemorrhage, CT without contrast is preferred due to its superior ability to detect acute blood products 1
- CT is faster and more readily available in acute settings 1
- If intracranial hemorrhage is suspected, head CT without contrast media is recommended 2
Common Pitfalls to Avoid
- Using MRI with contrast as the initial study when non-contrast MRI is sufficient 1
- Misdiagnosing migraine with cranial autonomic symptoms as "sinus headache" 3
- Performing unnecessary imaging for typical migraine presentations with normal neurological examinations 1
- Failing to recognize red flag symptoms that warrant immediate imaging 2
Treatment Considerations While Awaiting Imaging
- First-line therapies for intractable migraine include triptans for moderate to severe attacks 4
- Antiemetics and ergot alkaloids are recommended as second-line agents for refractory migraine 4
- Medications containing opiates or barbiturates should be avoided for acute migraine 5
- Intravenous antiemetics, with or without intravenous dihydroergotamine, are effective therapies in an emergency department setting 5
By following these evidence-based recommendations, clinicians can appropriately select imaging studies for patients with intractable first-time migraine while minimizing unnecessary testing and radiation exposure.