Understanding Magnetic Resonance Imaging
A magnetic resonance imaging (MRI) test uses radio waves and a magnetic field to understand what is going on inside the body. Because the MRI emits radio waves instead of X-rays or other radiation, it is one of the safest techniques for doctors to use to observe many conditions.
How does it work?
Magnetic resonance imaging works by using a magnetic field to measure the resonance of radio waves inside the body and taking images of this resonance. It works by sending out radio waves to the body, which then react with hydrogen atoms found in the water inside your body. These hydrogen atoms return a modified radio wave signal, and the machine reads and makes an image of this signal. By compiling all of these images, doctors are able to discover what’s going on inside the body.
Why use MRI instead of X-rays?
X-rays have much smaller wavelengths than radio frequencies. In fact, they are almost on opposite ends of the light spectrum from each other. This means X-rays penetrate deeper into your body, revealing more dense structures such as bones. Because an MRI uses longer wavelengths, we are better able to see the more permeable materials inside the body, including soft tissues such as the brain, muscles, and some internal organs.
What to expect:
When performed by experts, the MRI can be one of the simplest and more comfortable exams you may undergo. You will lie face up on a padded table, and after you let your radiologist know you are comfortable, the table will move into a tube-shaped scanner. There is a window for the technologist to communicate with you throughout the entire process.
The exam should take from 30 to 60 minutes, during which you may hear loud or tapping noises coming from the machine, which is just the machine taking the images.
There are no special diet restrictions or preparations necessary for you to complete before your exam. However, we do ask that you refrain from wearing hairspray or makeup, and that you refrain from drinking caffeine if it will prevent you from lying still throughout the exam. In addition, inform your technologist if there is a possibility that you are pregnant before the exam starts, and tell your doctor before the exam if you:
- Have a pacemaker
- Worked with metal for extended times
- Have clips for brain aneurysms
- Have any kind of metal implant (plate, pin, etc.)
- Were injured in the military
Why do some MRIs require contrast dye?
You may need to have an injection of contrast dye, depending on what your MRI is being used to see. This contrast dye is designed to make any abnormalities such as active tumors easier for the radiologist to see. While the dye is made from organic material and is completely safe, there is a potential for an allergic reaction. Make sure to tell your radiologist if you have had a reaction to contrast dye before or if you have a sensitivity to medications.
Closed MRIs offer highly accurate images with better detail and more information than open MRIs. Because we want our patients to have the best care possible, we only offer closed MRIs. However, if a patient suffers from extreme claustrophobia, we may recommend they have an open MRI, and we’ll recommend locations where they may do so.
As soon as we get your imaging results, we send them over to your primary care physician, who will then discuss the results with you. In certain circumstances, we may talk directly with your doctor following the procedure. We are also happy to schedule a one-on-one consultation between you and your radiologist any time before or after your procedure.