Can an MRI show if you have migraines?

No. MRI cannot diagnose migraines. Most people with migraines have completely normal MRI results. Migraine diagnosis is based on symptom history and clinical criteria, not imaging findings.

Why did my doctor not order a brain scan for my migraines?

Routine brain imaging is not recommended for direct migraine diagnosis with a normal neurological examination. Brain scans are reserved for cases with red flag symptoms, as imaging does not add diagnostic value in typical migraine presentations.

What does a migraine look like on an MRI?

Standard MRI appears normal in most people with migraines. People with migraine and aura show white matter lesions on MRI. These lesions are not diagnostic of migraines, and their clinical significance in patients remains under investigation.

Should I be worried if my MRI shows white matter lesions?

White matter lesions found incidentally in people with migraines are not cause for any concern. Research shows these lesions are not associated with cognitive decline or increased stroke risk. A neurologist can review findings and advise monitoring.

When should I go to the emergency room for a headache?

Go to the emergency room immediately if you have a sudden, severe headache, fever with stiff neck, one-sided weakness, speech difficulty, or a headache after head trauma. Don't wait as these require urgent imaging to exclude serious conditions.

Can Brain Scans Detect Migraines?

Why Can Brain Scans Not Diagnose Migraines?

Migraines are caused by functional and chemical changes in the brain rather than structural abnormalities that imaging can detect.

Migraine involves complex neurochemical events including trigeminal nerve activation, CGRP (calcitonin gene-related peptide) release, and serotonin fluctuation, none of which produce visible structural changes on MRI or CT scans
Cortical spreading depression, the electrical wave that causes migraine aura, is a functional event that does not leave permanent visible changes on standard brain imaging
Standard MRI and CT scans are designed to detect structural abnormalities such as tumors, bleeding, or lesions, not neurochemical or functional brain events
According to the American Headache Society (2022), routine brain imaging is not recommended for people with a clear history of migraines and a normal neurological examination

What Do Brain Scans Show in People With Migraines?

Although brain scans cannot diagnose migraines, research imaging studies have identified certain findings more commonly seen in people with migraines compared to the general population.

White Matter Lesions

White matter lesions (small areas of abnormal signal in the brain's white matter, the region containing nerve fiber pathways) are more frequently found on MRI in people with migraines, particularly migraine with aura
According to a meta-analysis published in Neurology (2019), people with migraines have a significantly higher prevalence of white matter lesions compared to those without migraines
The clinical significance of these lesions in people with migraines remains unclear, as white matter lesions are not associated with cognitive decline or increased stroke risk in most migraine patients
White matter lesions found incidentally on MRI in a migraine patient do not require treatment but should be monitored over time

Structural Brain Changes

Long-term research studies using advanced MRI techniques have identified subtle changes in brain volume and cortical thickness in people with frequent migraines
The iron deposition (accumulation of iron) in certain brain regions including the periaqueductal gray (a brain region involved in pain modulation) has been observed in people with chronic migraines
These structural changes are associated with migraine chronification (the process of episodic migraine becoming chronic) and central sensitization rather than any directly treatable abnormality

Normal Findings in Most Cases

The majority of people with migraines have completely normal MRI and CT scan results
A normal brain scan result in a person with a consistent migraine history is expected and does not invalidate the migraine diagnosis
Normal imaging reassures both doctor and patient that no serious secondary cause is responsible for headaches

When Are Brain Scans Needed for Migraines?

Brain scans aren't something that gets routinely ordered for migraine diagnosis - they're really only brought in when certain warning signs suggest the headaches might be caused by something else underlying.

Red Flag Symptoms Requiring Brain Imaging

Thunderclap headache: A headache that hits with full force within seconds - this is a red flag that could point to bleeding around the brain and needs a CT scan straight away.
New headache after 50: If someone who's never really had headaches suddenly starts getting them after the age of 50, it's worth getting an MRI to rule out a brain tumor or inflammation of the blood vessels in the head.
Progressive worsening headaches: Headaches that are steadily worsening over weeks without a prior established headache pattern require imaging to exclude space-occupying lesions
Headache with neurological symptoms: Persistent weakness, speech difficulty, vision loss, or confusion alongside headaches require MRI to rule out stroke or demyelinating disease (a condition affecting the protective covering of nerve fibers)
Headache with fever and stiff neck: Suggesting meningitis or encephalitis, requiring urgent CT and lumbar puncture
Headache following head trauma: To exclude intracranial bleeding or contusion
Headache in a person with cancer or immunosuppression: To rule out brain metastases or opportunistic infections

MRI vs CT Scan for Headache Evaluation

What Happens During a Brain MRI for Headaches?

The patient lies flat on a table that slides into the MRI machine, a large tube-shaped scanner
The MRI machine uses powerful magnetic fields and radio waves to produce detailed images of brain structure
A contrast dye (gadolinium) may be injected into a vein to enhance visualization of blood vessels and certain lesions
The scan typically takes 30 to 60 minutes and is painless, though the machine produces loud knocking sounds
Results are reviewed by a radiologist and communicated to the referring doctor, typically within 24 to 48 hours

Advanced Imaging in Migraine Research

While MRI and CT scans are the ones used day-to-day in clinical practice, more advanced imaging techniques used in research have helped scientists understand a lot more about what's actually happening in the brain during a migraine.

Functional MRI (fMRI): Measures brain activity by detecting blood flow changes, revealing altered activation patterns in pain processing regions during migraine attacks
Magnetic resonance spectroscopy (MRS): Measures brain chemical concentrations and has identified abnormalities in magnesium and glutamate levels in migraine brains
Positron emission tomography (PET): Has identified activation of the brainstem and hypothalamus as early events in migraine attacks, supporting their role as migraine generators
These advanced techniques are research tools and are not used in routine clinical migraine diagnosis or management

When Should You See a Doctor About Brain Scan Results?

A brain scan has identified white matter lesions and clarification of their significance is needed
Red flag symptoms are present and imaging has not yet been performed
Current migraine diagnosis is uncertain and secondary causes have not been excluded
A brain scan result is described as abnormal and the implications for migraine management are unclear

Conclusion

Brain scans can't diagnose migraines, but they do serve an important purpose - ruling out anything more serious when concerning symptoms are present. For most people with migraines, an MRI or CT scan will look completely normal, and that makes sense because migraines are driven by changes in brain chemistry and function rather than anything structural. White matter lesions do show up more often in people with migraines, but in most cases they don't need any treatment. At the end of the day, migraine remains a clinical diagnosis, built on symptom history and IHS criteria, with scans only being brought in when there's a real need to rule out a secondary cause.