What type of brain MRI (Magnetic Resonance Imaging) with and without contrast is recommended for a patient with worsening migraines to rule out underlying structural abnormalities or secondary causes?

MRI Brain Without Contrast for Worsening Migraine

For a patient with worsening migraines and a normal neurological examination, MRI brain without IV contrast is the appropriate initial imaging study, though imaging may not be necessary at all if the examination is truly normal. 1

When Imaging Is Actually Indicated

The critical decision point is whether imaging is needed at all:

• Imaging is NOT routinely warranted in migraine patients with completely normal neurological examinations, as the prevalence of clinically significant abnormalities is only 0.2%, equivalent to the general asymptomatic population 2, 3

• Imaging SHOULD be obtained when any of these red flags accompany worsening migraine 2:

  • Abnormal findings on neurological examination 4, 2
  • Headache worsened by Valsalva maneuver 2
  • Headache that awakens from sleep 2
  • New-onset headache in older patients 2
  • Progressively worsening pattern 2
  • Rapid increase in headache frequency 2

The Correct MRI Protocol

MRI brain without IV contrast is the appropriate initial study when imaging is indicated 1, 5, 2:

• Standard sequences should include T1-weighted, T2-weighted, FLAIR, and diffusion-weighted imaging 2
• Add contrast ONLY if the non-contrast study reveals abnormalities requiring further characterization 1, 5

When to Add Contrast From the Start

Contrast should be included in the initial order only in specific scenarios 1:

• Signs of increased intracranial pressure with concern for tumor 1
• Focal neurological deficits suggesting structural lesions 4
• Suspected infection or inflammatory process 1

Why MRI Over CT

MRI is superior to CT for evaluating worsening migraine 2:

• Better detection of structural lesions that could cause secondary headache 5
• Superior soft tissue resolution for identifying tumors, demyelinating lesions, and vascular abnormalities 4
• No radiation exposure 4

CT should be reserved for emergency scenarios such as thunderclap headache or suspected acute hemorrhage, not for routine evaluation of worsening migraine 1, 5

Critical Pitfalls to Avoid

• Do not order imaging reflexively just because the patient is worried or requests it—studies show patient-directed MRI in migraine with normal examination has the same yield as scanning the general population (0.2-1%) 3, 6

• Do not skip the neurological examination—94% of patients with brain tumors causing headache have abnormal neurological findings at diagnosis 1

• Do not order CT when MRI is appropriate—CT misses the majority of structural lesions responsible for secondary headache 5

• Do not add contrast routinely—in studies of migraine patients, contrast enhancement contributed nothing to diagnosis when the non-contrast study was normal 6

Expected Yield

Understanding the actual diagnostic yield helps frame expectations 3, 7, 6:

• In migraine patients under 40 with normal examination: 5.5% show any brain abnormality, nearly all clinically insignificant 7
• In chronic/recurrent headache with normal examination: only 0.7% have clinically important findings 6
• White matter lesions (18.4%), sinus changes (10%), and small arachnoid cysts (3.8%) are common incidental findings that do not explain worsening migraine 8