Neuroimaging After Failed Physical Therapy for Migraines
Neuroimaging is not routinely indicated for patients with migraine who have completed physical therapy and continue to have headaches, provided the neurological examination remains normal. 1
Key Decision Point: Neurological Examination
The critical determinant for imaging is the presence or absence of abnormal neurological findings, not the failure of conservative treatment:
- Normal neurological examination: The yield of finding serious intracranial pathology in migraine patients with normal neurological exams is only 0.2% (2/1086 patients), which is no higher than the 0.4% rate in completely asymptomatic volunteers 1
- Abnormal neurological examination: Neuroimaging should be considered when any unexplained abnormal neurological finding is present, as this significantly increases the probability of detecting clinically significant intracranial pathology 1
Red Flag Assessment
Before deciding against imaging, systematically evaluate for these concerning features that would warrant MRI:
- Headache awakening patient from sleep 2, 3
- Progressive worsening of headache pattern over weeks to months 1, 2
- Headache worsened by Valsalva maneuver, coughing, or exertion 1, 2
- New-onset headache in patients >50 years old 1, 2
- Atypical aura features (focal neurological symptoms, prolonged duration >60 minutes) 1, 2
- Change in established headache pattern 2, 4
- Thunderclap onset ("worst headache of life") 2
When Imaging Is Appropriate Despite Normal Exam
MRI brain (with and without contrast) is the preferred modality if imaging is pursued, as it has superior resolution for detecting soft tissue abnormalities, inflammatory processes, and small structural lesions compared to CT 2, 3
Consider imaging in these specific scenarios:
- Atypical features present: Headaches that do not fulfill standard migraine criteria may warrant lower threshold for imaging 1, 3
- Age >40 years with persistent symptoms: One study found clinically significant findings in 8.3% of chronic migraine patients, with abnormalities most common in those >40 years 5
- Patient reassurance when excessive worry impairs function: While not evidence-based, imaging may be reasonable in individual cases where anxiety about serious pathology significantly impacts quality of life, though patients should understand the yield is equivalent to the general population 1, 6
Important Caveats
Avoid the medication-overuse headache trap: Before attributing treatment failure to refractory migraine, document medication use patterns. Regular use of acute medications ≥10 days/month for ≥3 months indicates medication-overuse headache, which requires withdrawal rather than imaging 2, 3
Document headache frequency: If the patient has ≥15 headache days/month for >3 months with ≥8 days meeting migraine criteria, this represents chronic migraine requiring different management strategies, not necessarily imaging 2, 3
False reassurance risk: A negative scan does not exclude migraine or guarantee absence of pathology, and incidental findings occur in up to 57% of scans (though only 8.3% are clinically significant) 5
Recommended Next Steps Instead of Imaging
For patients with normal neurological examination and no red flags:
- Implement headache diary to document frequency, triggers, medication use, and response patterns 2, 3
- Optimize acute treatment: Ensure appropriate use of triptans or NSAIDs rather than analgesic overuse 2, 4
- Consider prophylactic therapy: If headaches occur ≥4 days/month or significantly impact function 4
- Reassess in 2-4 weeks with structured follow-up to monitor for emerging red flags 4