How neuroimaging is used in diagnosing migraines

Finding the right diagnosis is the first step in getting the correct treatment for your headaches. There are many possible causes of headaches, so a thorough medical evaluation is important to determine why you have headaches, and whether you have migraine or another kind of headache. Headache evaluations usually include:

  • Gathering a personal and family medical history
  • A physical examination, including a neurological (brain and nervous system) assessment
  • A review of recent illnesses and injuries
  • A thorough review of your headache history, symptoms, and what treatments have worked
  • Keeping a headache journal for several weeks to identify potential patterns and causes

Some people worry that chronic headaches may be a sign that they have a more serious condition, such as a brain tumor. But unless there are other signs and symptoms, this is seldom the case. If your doctor is concerned that you may have an underlying neurological disease, he/she may suggest further diagnostic tests, which may include “x-ray-like” tests called neuroimaging.

What is neuroimaging?

Thanks to modern technological progress, there are now ways to look into your head and take pictures, and even see how parts of your brain are functioning. This is called neuroimaging. As technology gets better, there will be more and more types of neuroimaging. If neuroimaging is recommended for you, it is usually to help your doctor learn what problems you don’t have, to be sure the correct diagnosis is made.

The three most common neuroimaging techniques are:

Thanks to modern technological progress, there are now ways to look into your head and take pictures, and even see how parts of your brain are functioning. This is called neuroimaging. As technology gets better, there will be more and more types of neuroimaging. If neuroimaging is recommended for you, it is usually to help your doctor learn what problems you have, to be sure the correct diagnosis is made. The three most common neuroimaging techniques are:

  • Computed Tomography (CT), also called Computed Axial Tomography (CAT) scanning
  • Magnetic Resonance Imaging (MRI)
  • Functional Magnetic Resonance Imaging (fMRI)

What is CT scanning?

Computerized tomography, or computerized axial tomography, is an X-ray technique producing three- dimensional images of internal structures in your body, such as your brain, by taking multiple pictures in ”slices”. To prepare for a head CT scan you will need to remove your glasses, jewelry, and other metals, and lie flat on your back on a table that moves you into a donut shaped machine. Sometimes dye will be injected into a vein to provide contrast, and get a better picture. Once you are inside the scanner you need to remain completely still for a few minutes. You may hear some noise but you should not feel any pain.

What is magnetic resonance imaging (MRI)?

The Magnetic Resonance Imaging machine uses powerful magnets and radio waves to make high quality two- or three-dimensional pictures of brain structures. Similar to preparing for a CT scan, you will be asked to remove all metal items, and will lie on a narrow table that slides into a large tunnel-like tube inside the scanner. Sometimes a special dye is injected into a vein to get a better picture. Several sets of pictures will be taken. This may take from several minutes to an hour. You will not feel any pain but may hear loud noises during the test.

What is functional magnetic resonance imaging (fMRI)?

Functional Magnetic Resonance Imaging is a new type of MRI that allows doctors to see pictures of changing blood flow in the brain that correspond to mental operations, thus showing which brain structures are activated at different times. Because the fMRI is a very sensitive test, it is able to detect early changes in the brain. The fMRI is becoming the diagnostic method of choice for learning how a normal, diseased or injured brain is working, as well as for checking for potential risks of surgery or other invasive treatments of the brain. It is a very new technology, and research is still being done on the usefulness of fMRI.

Summary

Your primary care provider usually can make the diagnosis of migraine headaches without needing to use high-technology testing, like neuroimaging. But if it is needed, it is important to know that although it may sound scary, these are tests that are frequently done, and can be done with minimal pain and discomfort.

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References

Detsky, M., McDonald, D. Baerlocher, M., Tomlinson, G., McCrory, D., & Booth, C. (2006). Does this patient with headache have a migraine or need neuroimaging? JAMA, 296, 1274-1283.

MedLinePlus Health Information (2008). CTscans. Retrieved June 20, 2008 from www.nlm.nih.gov/medlineplus

MedLinePlus Health Information (2008). MRI. Retrieved June 20, 2008 from www.nlm.nih.gov/medlineplus

MedLinePlus Health Information (2008). fMRI. Retrieved June 20, 2008 from www.nlm.nih.gov/medlineplus