What is MRI?

MRI is short for Magnetic Resonance Imaging. (If your doctor has sent you for an MRA [Magnetic Resonance Angiography], this is also a kind of MRI.) MRI is an advanced technology that lets your doctor see internal organs, blood vessels, muscles, joints, tumors, areas of infection, and more -- without x-rays, surgery, or pain. MRI is very safe; in fact, it makes use of natural forces and has no known harmful effects. It's important to know that MRI will not expose you to any radiation.

How does the MRI machine work?

The MRI machine creates a magnetic field, sends radio waves through your body, and then measures the response with a computer. This creates an image or picture of the inside of your body that is much clearer than can be obtained with most other methods.

Why an MRI?

MRIs can provide very early detection of many conditions, so treatment can be more effective. The excellent quality of MRI images can also provide the best possible information if surgery is required. If there is an abnormality, MRI can show exactly where it is, its size, and whether or not it has spread.

How should I get ready for the exam?

In most cases, you can just stick with your normal, everyday routine - no special preparation is needed. You can eat and drink your usual diet, work, or play sports (unless you have an injury!) - and take any prescription medications you need. However, there may be some circumstances in which you'll be given specific instructions to follow before the exam. These will be given to you by your doctor, or by his/her representative.

Are there any restrictions with the exam?

Yes. Because the MRI machine uses a strong magnetic field, which will move objects made with iron or steel, let your doctor know if you have:

A pacemaker

Aneurysm clips

Cochlear implants

A neuro-stimulator (Tens-unit)

Metal implants

Steel surgical staples or clips

An implanted drug infusion device

Any implant made partially or wholly of iron or steel

Also, if you're pregnant, let the doctor know.

Even metal objects not made of iron or steel can interfere with the exam - so don't bring any of the following into the examination room (a secure place to store your valuables will be provided):

Coins

Jewelry

Watches

Keys

Dentures or partial plates

Hearing aids

Magnetic waves can also erase the code on bank cards and credit cards, so don't bring any to your exam. Last of all, you may be asked to change into a patient gown.

Where are MRIs given?

MRI exams can be done at hospitals. But they can also be done at various independent facilities that perform diagnostic imaging.

May I bring someone to the exam with me?

Yes, although they will likely have to wait in a waiting room while the scan is being done. However, while you're having your scan done, you can communicate with the technologist at any time through an intercom system.

What's the exam actually like?

There are many varieties of MRI scanning machines. Depending upon the area being scanned, your doctor may specify which type of machine is to be used.

To begin the exam, you will lie down on the scan table. When the machine starts to work, you'll hear some loud knocking sounds. These sounds occur whenever the MRI pictures are being taken. Think of them as the clicks a VERY large camera would make when taking pictures! Some MRI facilities provide headphones with music to help block out the knocking sounds.

In any case, although it's noisy, an MRI exam is completely painless. The only thing you must do is HOLD STILL. When you take a picture with a camera, your subject must keep still or the picture will come out blurry. It's the same with an MRI machine. If you move, the scans will be out of focus - and you may have to repeat the exam.

If necessary, you may be injected with a solution called a contrast agent. This allows the radiologist to see the image more clearly. MRI contrast agents typically have few or no side effects, and the injection likely will just feel like a slight pinch. You may be asked to give your consent to this injection, at which time a more detailed explanation about the contrast agent will be given to you by the radiologist, or his/her representative.

How long does the scan take?

The exam can last from 30 minutes to usually no more than an hour.

Will I feel any different after the exam?

Well, you may feel very well rested since you've just been lying on a table and doing absolutely nothing! (In fact, some people even fall asleep during the exam.) Other than that, you'll feel perfectly normal and can go back to your everyday activities.

If you have further questions about your MRI exam, the MRI technologist or your doctor will be glad to answer them.