Magnetic resonance imaging (MRI) — a specific technique used in radiology to create very detailed images of internal parts of the body — is an important tool in the diagnosis and monitoring of multiple sclerosis (MS). Once diagnosed, people with MS will typically undergo annual MRI scans. Some may have more frequent scans, some less frequent.
MRI scanners use strong magnetic fields to generate images. The standard imaging protocol in MS suggests use of a minimum 3 Tesla (3T) "closed machine" for best results. The imaging sequences focus on the white matter and grey matter of the brain and/or spinal cord before and after venous administration of a contrast agent, gadolinium, to enhance certain anatomical features.
Here are some things you need to know to make your MRI experience less stressful and more successful.
Before the MRI
Dress comfortably. Because the MRI scanner is basically a large magnet, you must not wear clothing with lots of metal rivets, buttons, or zippers. To avoid the need to disrobe and put on a hospital gown, I prefer to go to my MRI appointment wearing sweatpants and a comfortable T-shirt. That way, the only clothing I have to remember to take off in the dressing room is my underwire bra. Don’t worry, the technician will double-check that you aren’t wearing anything that would interfere with the MRI.
Remove body jewelry, watch, and wallet. Consider leaving your jewelry at home for safe keeping. You will be asked about metal in the body — such as a pacemaker, cochlear implants, joint replacements, or metal fragments — because in certain circumstances, an MRI can cause damage to the equipment itself or to body tissue when metal is involved. Some metals, such as titanium clips from a breast biopsy, do not pose a problem.
Tell the MRI technician about all medications you take. You will be asked specifically about chemotherapy. If you have used chemotherapy, it is important to take results of your most recent blood work with you because they want to make sure that your kidneys are healthy enough to process the gadolinium contrast agent.
Describe your current symptoms. This information will be included in the notes that the radiologist will have access to while examining your scans. Although lesions and symptoms do not always correlate, sometimes they do and the radiologist may take an extra close look at certain areas of the images based on a history of symptoms.
Go to the bathroom one last time. Once you get on the MRI table, you will be immobile for 1.5 to 2.5 hours. At my local MRI center, 45 minutes is allotted to complete the scanning of each area typically imaged in MS — brain, cervical spine, thoracic spine. Individual scanning sequences may take as little as 30 seconds and as much as five minutes. But once you start, you really should not get up unless absolutely necessary.
During the MRI
Protect your hearing. You will be provided with foam earplugs to protect your hearing because the MRI scanner is extremely loud and noisy. Be sure to roll the earplug firmly between your fingers to shape it into a narrow cylinder that you place in your outer ear canal. Hold the foam earplug in place as it expands to get the best fit.
Tell the technician if you are claustrophobic or nervous. If you have trouble with MRI scans, your doctor may prescribe an anti-anxiety medication to help you relax. You can use the time in the MRI to practice meditation and slow breathing. Or you might fall asleep. I actually enjoy "listening" to my favorite music in my head while the exam is going on.
Get cozy. When you are on the MRI table, request that a cushion be placed under your knees to take the pressure off your back and a blanket to reduce the chill of the fans inside the machine. I recommend you also ask for extra foam be placed inside the “cage” that goes over your head to help block some of the noise and to make it easier to keep your head still. As you are rolled into the machine, fold your arms slightly across your chest and slowly allow them to relax to your sides once you are in place. I usually keep my eyes closed during the exam because I can’t see without my glasses or contacts anyway.
Stay still. It’s very important not to move during the active scanning. The technician will tell you how long each sequence will take so that you can anticipate when it is okay to swallow or cough. If you move during active scanning, the sequence may need to be repeated to get better images. If you have an uncontrollable itch, tell the technician, who can come help you out.
After the MRI
Stick around. Once the scanning is complete, many MRI centers will save the images to a disc for you to keep for your records. These may be helpful if you ever move and need to establish care in a different hospital system. Although I’m no expert on what the brain looks like inside, it’s fun to view the images at home.