Remember being told to stay still as a child, and it suddenly seemed like the hardest thing in the world to do?
It is not often that this is asked of us in day to day life as adults, but it is one of several important things to remember when having an MRI done at your imaging center. For some people, just feeling nervous about having a test done in a strange machine might cause difficulty with finding a comfortable position and relaxing enough to be still for 15 to 45 minutes. Knowing what to expect and how an MRI works may help put you at ease and make this important scan seem to fly by.
What Does an MRI Machine Look Like?
There are several different types of MRI available now. Many people still think of the older bullet-style MRI machines from many years ago, but new technology has allowed for very high quality MRI’s to be more open, and shorter “tubes” that closely resemble donuts, or CT scanners. Here are a few images of the type of MRI used at the Minnesota Diagnostic Center – Siemens Magnetom Espree Wide Bore scanner.
As you can see, this machine is spacious enough to accommodate most individuals; it also allows a person to go in feet first for lower body scans, and in some cases a person’s head may remain outside of the machine.
What Does an MRI Sound Like?
If you know someone who has had an MRI, you may have heard that they can be pretty loud – lots of knocking and humming. Although new scanners have recently come on the scene that claim to be mostly silent, they are not yet widespread. Most imaging facilities, like MDC, provide headphones and music, and even allow you to bring your own CD to listen to, blocking out a good part of the MRI sounds. To listen to an MRI without the headphones or music, check out this video below…just a couple of minutes here and there gives you the idea.
Although it may seem pretty obnoxious sounding, for many people it is still monotonous enough to put them to sleep!
Am I All Alone In There?
Once you are on the MRI table and the appropriate body part to be scanned is in the machine, your MRI technologist will leave the immediate room and go to the MRI control room next door. There is a window so that your technologist can see everything that is going on with you in the machine, as well as a two way intercom so that you can talk to her and she can talk to you. In addition, there is an “emergency” or “panic” button in the machine that you can press at any time if you feel you cannot complete the test, and the technologist will have you off of the table within seconds.
Why Is It So Important to Stay Still?
Although MRI machines work quickly and are able to take a number of pictures in a short amount of time, it is not quick enough to avoid blurring if you are moving during the scan. Moving the body part being scanned may cause unclear pictures, which then need to be re-taken. Having to take important images more than once means a longer time in the MRI Machine, and moving too much to retake them all may mean that the quality is not as clear as your doctor and the radiologist would like to see in order to make an accurate diagnosis and the best possible treatment plan.
How Does an MRI work? How Is It Different than an X-Ray or CT?
The primary difference between how an MRI works versus an X-Ray or CT is that it uses a magnetic field instead of x-ray beams. An x-ray uses a small amount of radiation from one direction, whereas a CT uses multiple x-ray beams (radiation) while x-ray detectors rotate around you for more detail. An MRI, on the other hand, does not use any ionizing radiation. Instead, it creates a strong magnetic field around your body that causes the hydrogen protons in your body to align. The MRI then sends out radio waves that “knock” the hydrogen protons out of alignment, and as they re-align in the magnetic field, they send out their own electric signals. These are picked up by the MRI computer that converts them into detailed images. For a great visual explanation, check out this brief video by the National Institute of Biomedical Imaging and Bioengineering (a branch of the National Institutes of Health):
MRI’s are better at imaging organs and soft tissues (like those in the brain and along the spinal cord), along with abnormalities in these tissues, than CT’s.
Because there is no radiation used, there is no inherent risk by having MRI’s done. However, since it is a huge magnet, any metals on or in the patient can present their own risks – anything from pace makers and stents to some types of tattoo inks and piercings may not be completely MRI safe, and staff should be made aware before the scan appointment. In some cases, a contrast dye is used to better highlight areas of abnormal tissues. As with all injections, there is always the risk of allergic reaction in some people.
Any Other Tips?
For more information on how to prepare for your MRI scan and what to expect from MDC staff before and at the time of your test, visit the Minnesota Diagnostic Center website page Prepare for Your Magnetic Resonance Imaging (MRI)
Although you have likely already reviewed MRI Safety questions at the time that your MRI scan was scheduled, protocols are in place to ensure that nothing is missed, and you will be asked many of the same questions again upon check in. It is not uncommon that a person remembers something they may need to let the MRI staff know about that they didn’t realize was important the first time around. Arrive early enough to review this paperwork, and remember that the staff is asking you these questions again for your own safety and to ensure the best image quality for your doctor. You can always ask staff about the importance of the MRI screening process if you wonder why.
You can also feel free to call with any questions you might have and speak to one of the MDC and Noran Clinic staff at 612.879.1000, during regular business hours (8 am – 4 pm).