By: Natalie L. Boehm, MBA, RBLP-T
What is an MRI?
An MRI, also known as magnetic resonance imaging, is a medical imaging technique, which uses a magnetic field and computer-generated radio waves to create detailed images of the organs and tissues in your body (Mayo Clinic, 2019).
MRI’s allow radiologists to see cross-sectional areas of the brain, helping them to locate areas where seizure activity can be taking place. When evaluating areas of the brain such as the frontal lobes, MRI’s can produce 3-D imaging and special coronal cuts to look for malformation or tissue atrophy.
What can an MRI diagnose?
MRI’s can help to diagnose any abnormalities, damage, blockages, and evaluate to find infections. When it comes to epilepsy, an MRI may be ordered when the following is taking place:
Onset of seizures at any age with evidence of focal onset in history or EEG
Onset of unclassified or apparently generalized seizures in the first year of life or adulthood
Evidence of a focal fixed deficit on neurological or neuropsychological examination.
Difficulty in obtaining control of seizures with first-line anti-epileptic drug treatment.
Loss of control of seizures with anti-epileptic drugs or a change in the seizure pattern that may imply a progressive underlying lesion.
(Panayiotopoulos CP, 2005)
MRI and Epilepsy
MRI’s can be used to help diagnose epilepsy. Doctors are looking for scar tissue, tumors, or any abnormalities that can cause someone to have a seizure. MRI’s can pick up abnormalities that most CT scans cannot such as small lesions and small tumors. Examples include hippocampal sclerosis (shrinking/atrophy of hippocampus) and malformations of cortical development. In the article, Neuroimaging in Epilepsy, studies have shown MRI abnormalities are identified in eighty percent of patients with refractory focal epilepsy and twenty percent of patients with a single unprovoked seizure or epilepsy in remission.
MRI vs. fMRI
A fMRI also known as a functional MRI is performed in the same machine as an MRI. The difference is an MRI is allowing a physician to look at organs while the fMRI is looking at the actual function.
An fMRI is usually performed for when neurosurgeons are preparing for surgery. The fMRI will let them see the activity that is taking place and what route to take when they are operating. Patients will wear goggles like virtual reality sets and perform tasks such as squeezing a hand or thinking about something. This will help the neurosurgeons find a safe way to remove tumors or areas of the brain that are affected by epilepsy.
Risks of having an MRI
Patients with certain devices may not be able to have an MRI. It is important to let your doctor know if you have any of the following:
Metallic joint prostheses
Artificial heart valves
An implantable heart defibrillator
Implanted drug infusion pumps
Implanted nerve stimulators
A pacemaker
Metal clips
Metal pins, screws, plates, stents, or surgical staples
Cochlear implants
A bullet, shrapnel, or any other type of metal fragment
Intrauterine device
(Mayo Clinic, 2019)
How to prepare for an MRI
There is not much to prepare for when getting ready to have an MRI. When arriving, you will change into a gown and be asked to remove anything that could affect the magnetic imaging. Examples of items are:
Jewelry
Hairpins
Eyeglasses
Watches
Wigs
Dentures
Hearing Aids
Underwire Bras
Cosmetics that contain metal particles
(Mayo Clinic, 2019)
What to expect during an MRI
Depending on what your physician is looking for, some doctors will order an MRI with contrast. Contrast dye helps to make certain tissues and blood vessels become clearer and more detailed. Some patients experience side effects from the dye. Common side effects are:
Feeling or being sick
A skin rash
A headache
Dizziness
(NHS UK, 2018)
Before having an MRI with contrast, make sure to let your neurologist or physician know if you have experienced any reactions in the past.
In some rare cases, sedatives may be used to perform an MRI. If someone is claustrophobic, a mild sedative can be given to help them relax while the scan is being done. For children and infants, sedatives may be given to make sure they hold still during the procedure.
An MRI machine is like a long tube. Depending on what they are looking for, a frame may be placed over the body. When having an MRI of the head, a frame will be placed over the top of the head to help create the images.
While having your MRI, even though the technician is in a different room, they can communicate with you and can see you at all times. It is important to follow the instructions of the technician such as holding still and any instructions they give you such as holding your breath during short scans. The reason is if you do not hold still and follow instructions, the results can turn out blurry and prevent the doctor from seeing what he or she needs to in order to make a proper diagnosis.
Staying relaxed and calm is essential to get through the test. Many have the option to wear headphones while the test is being done. You can request the technician put on your favorite radio station or you can bring a CD to listen to. According to Epilepsy Society, the average MRI scan to help diagnose epilepsy lasts around thirty minutes.
Conclusion
An MRI is a medical imaging technique, which uses a magnetic field and computer-generated radio waves to create detailed images of the organs and tissues in your body (Mayo Clinic, 2019). MRI’s can be used to diagnose many things, including epilepsy. While MRI’s are performed to look at the organs, fMRI’s are performed to watch the function of the brain. There are many steps to prepare for an MRI and patients need to understand what they can and cannot do during an MRI or if they are at risk if they have one. When having an MRI, a technician is there with you to help you through the test, which when diagnosing epilepsy lasts on average thirty minutes.
Resources:
Epilepsy Society (2018). Brain Scans. Epilepsy Society. Retrieved from: https://epilepsysociety.org.uk/about-epilepsy/diagnosing-epilepsy/brain-scans-epilepsy
John Hopkins Medicine (2021). Diagnosing Seizures and Epilepsy. John Hopkins Medicine. Retrieved from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/epilepsy/diagnosing-seizures-and-epilepsy
Mayo Clinic (2019). MRI. Mayo Clinic. Retrieved from: https://www.mayoclinic.org/tests-procedures/mri/about/pac-20384768
Messori, A., Polonara, G., Carle, F., Gesuita, R., & Salvolini, U. (2005). Predicting Posttraumatic Epilepsy with MRI: Prospective Longitudinal Morphologic Study in Adults. Epilepsia (Copenhagen), 46(9), 1472-1481. https://doi.org/10.1111/j.1528-1167.2005.34004.x
NHS (2018). MRI Scan: How it’s performed. NHS. Retrieved from: https://www.nhs.uk/conditions/mri-scan/what-happens/
Panayiotopoulos, CP. The Epilepsies: Seizures, Syndromes, and Management. Oxfordshire (UK): Blandon Medical Publishing; 2005. Chapter 3, Brain Imaging in the Diagnosis and Management of Epilepsies. Available from: https://www.ncbi.nlm.nih.gov/books/NBK2602/
Roy, T. and Pandit, A. (2011). Neuroimaging in Epilepsy. Ann Indian Acad Neurol. 2011, Apr-Jun; 14(2): 78-80. Retrieved from: doi:10.4103/0972-2327.82787
Yale Medicine (2021). Functional MRI of the Brain. Yale Medicine. Retrieved from: https://www.yalemedicine.org/conditions/functional-mri-imaging-the-brain
