A migraine is a complex neurological condition, distinct from a typical headache, characterized by a range of symptoms including severe throbbing head pain, sensitivity to light and sound, and nausea. While medical professionals often diagnose migraines based on a person’s symptoms and medical history, brain scans can play a specific role in certain situations. These imaging tests are not typically used to confirm a migraine diagnosis directly, but rather to provide clarity when other concerns arise.
Understanding the Purpose of Brain Scans
Healthcare providers often order brain scans for individuals experiencing headaches to rule out other underlying conditions. The primary goal is to exclude serious neurological issues that might mimic migraine symptoms.
For instance, a scan can help identify structural abnormalities like brain tumors, aneurysms, or evidence of a stroke. These conditions can present with severe headaches, making it important to distinguish them from primary headache disorders like migraine. By ruling out such serious pathologies, a brain scan provides reassurance and helps guide the appropriate management plan.
A brain scan does not directly diagnose migraine. Migraine is a primary headache disorder, meaning it is not caused by another medical condition. Instead, scans are a tool to investigate whether the headache might be secondary to a different health issue.
Common Imaging Techniques
When a brain scan is considered, two common imaging techniques are typically used: Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scans. Both methods create detailed images of the brain, but they operate differently and are suited for various purposes.
An MRI uses strong magnetic fields and radio waves to generate detailed cross-sectional images of the brain. This technique is particularly effective at visualizing soft tissues, making it suitable for detecting subtle abnormalities. MRI scans do not involve radiation exposure, but they generally take longer than CT scans.
A CT scan, also known as a CAT scan, utilizes X-rays to produce images of the brain. CT scans are faster than MRIs and are often preferred in emergency situations, such as head trauma, because they can quickly show acute bleeding or bone fractures. While CT scans involve a small amount of radiation, their speed and ability to highlight bone structures can be beneficial.
When Scans Are Recommended
Brain scans are not routinely recommended for all migraine sufferers, as diagnosis is often clinical. However, specific “red flag” symptoms or situations warrant imaging, suggesting a more serious underlying condition.
One key indicator for a scan is a new onset of severe headaches, especially if they begin suddenly and are described as the “worst headache ever,” often referred to as a “thunderclap headache.” Headaches that change significantly in character, frequency, or intensity from previous patterns also raise concern.
Other red flags include headaches accompanied by new neurological deficits, such as weakness on one side of the body, vision changes, difficulty speaking, or seizures. Headaches that start after head trauma, in individuals over the age of 50, or in those who are immunocompromised or have a history of cancer, often prompt a scan.
What Brain Scans Show
Brain scans reveal the physical structure of the brain, detecting abnormalities like tumors, vascular malformations, or signs of a stroke. These images help identify if such issues contribute to headache symptoms.
Brain scans typically do not show direct evidence of migraine, a functional neurological disorder involving brain activity patterns rather than visible structural damage. A “normal” brain scan is common for migraine sufferers, and this result helps confirm the diagnosis by ruling out other causes.
Sometimes, MRI scans may show small bright spots called white matter hyperintensities (WMHs). These are areas of altered tissue that can appear on scans of people with and without migraines. While research indicates a higher prevalence of WMHs in migraine sufferers, they are generally considered benign incidental findings and do not typically require further follow-up unless other concerning symptoms are present.
Preparing for Your Scan
Preparing for a brain scan involves discussing any medications you are taking with your doctor or imaging staff. Unless instructed otherwise, you can usually eat and drink normally before the scan.
For an MRI, inform staff about any metal implants in your body, such as pacemakers or surgical clips, as the strong magnetic field can interfere. You will be asked to remove all metal objects, including jewelry, before entering the scan room. Wearing comfortable, loose-fitting clothing is recommended.
During the scan, you will lie still on a table that slides into the imaging machine. The MRI machine can be noisy, so earplugs or headphones are often provided. The duration of the scan can vary, but an MRI typically takes longer than a CT scan.