How do I prepare for an MRI?

Preparing for an MR scan is very easy. You can take all your normal medications and follow usual eating schedules unless your doctor gives you special instructions. The only unusual preparation for an MR scan is that all removable metallic objects must be left outside the scanning room, including removable hearing aids, dentures and other prosthetic devices. Credit cards cannot be brought into the scanner room since the magnetic codes on them can be affected by the magnet. For optimal image quality when performing head scans, all makeup must be removed since it may contain metallic powders which are magnetic and thus degrade image quality. You may be asked to wear a hospital gown, since clothes may have metallic fasteners or metallic fibers that can interfere with the imaging.

What does the MR scanning center staff need to know about me to perform the scan?

Besides complete information about your medical history, your doctor and the MR staff must know if you have any metal in your body which cannot be removed, including: pacemakers, implanted insulin pumps, aneurysm clips, vascular coils and filters, heart valves, ear implants, surgical staples and wires, shrapnel, bone or joint replacements, metal plates, rods, pins or screws, contraceptive diaphragms or coils, penile implants, and permanent dentures. In most cases, you can be scanned even though you have metal implants. Nevertheless, the radiologist and MRI staff must be aware of them. Also, tell a member of the staff if you are pregnant or if there is a possibility you are pregnant.

IMPORTANT: DO NOT ALLOW YOURSELF TO BE SCANNED IF YOU HAVE A PACEMAKER OR OTHER IMPLANTED MECHANICALLY, ELECTRICALLY OR MAGNETICALLY ACTIVATED DEVICE. UNLESS SPECIFICALLY ORDERED BY THE RADIOLOGIST, YOU WILL NOT BE SCANNED IF YOU HAVE METAL IMPLANTS IN THE HEAD REGION.

What will happen when I get scanned?

A trained MR professional will help you into position on the scanner bed. This narrow bed slides directly into the scanner. Ask for a blanket if you are cold. It may be necessary to place a special band or ring on the area to be scanned. This band or ring is actually a special antenna that enables the scanner to pick up signals with more clarity from that portion of anatomy that is being scanned. Once you are positioned, all you have to do is relax and lie as still as you can. You will be able to talk to a member of the staff in the next room who will be able to see and hear you during the entire scan. You can have a companion stay in the scanning room with you throughout the scan. In fact, whenever possible, parents are encouraged to be in the room with their children during the scan. The procedure will take from 20 to 60 minutes depending on your doctor's instructions. After the scan, you can resume all normal activities immediately. Infrequently, certain types of scans require the use of an injected contrast agent. If your doctor ordered this type of scan, our staff member will explain the contrast agent to you and answer your questions.

Isn't an MRI scan basically the same as a CAT scan?

No, except for the fact that they both use computers and they are both used for medical diagnosis, they really have very little in common. One of the most important differences between a CAT scan and an MRI is the fact that CAT scans use X-ray radiation and MRI scans do not. In other words, CAT scans are nothing more than computerized X-rays. As you probably already know, X-rays can be harmful and it is important therefore to avoid unnecessary exposure to them. Although there are still some situations in which a CAT scan should be instead of an MRI-your physician will be able to tell you when this is the case and why-for the most part, MRIs are diagnostically superior, especially if soft tissue is involved. If a CAT scan and an MRI are diagnostically equivalent in a particular situation, an MRI is the better choice because it will not subject you to any ionizing radiation. Instead, MRIs use harmless radio waves. In addition to the superior portrayal of soft tissue, MRIs provide much more flexibility in portraying cross-sectional planes of the body. Unlike a CAT scanner which is relatively limited to when it comes to plane selection, an MRI can provide a cross-sectional image taken at any plane in the human body.

Do you need a prescription for an MRI?

Yes. If you have reason to believe that an MRI would be beneficial in diagnosing your physical condition more accurately, discuss it with your doctor. If your doctor agrees, he or she will refer you to a local MRI diagnostic center for a scan.

If I have an MRI scan, how will I find out the results?

Typically, your MRI scan will be examined or 'read' by a radiologist who is specially trained in MRI technology. The radiologist in turn will report to your physician, and your physician will then discuss the findings with you.

Can I choose the kind of MRI scanner I want?

Yes, you can. Your physician may have a business relationship with a particular diagnostic center and therefore prefer sending you to that particular site. The imaging centers will have closed bore scanner or open type scanners. You could ask your doctor if both types are available in your area.

Do I have to lie still when I have an MRI?

Yes, it is important to minimize movement in order to achieve the best imaging results.

When is an MRI called for?

Whenever your doctor requires top-quality anatomic portrayal, especially soft tissue, chances are that an MRI will be the modality of choice. Unfortunately, the decision to prescribe or not to prescribe an MRI will not always be made on the basis of diagnostic quality. Sometimes, in a well-meaning attempt to save money for the patient or the insurance company, a physician will choose a less-expensive procedure, hoping that he or she will receive sufficient information to make a correct diagnosis. If the less-expensive test proves inadequate, however, and an MRI is prescribed later, the attempt to save money will have been futile. Even worse, the condition may be inaccurately diagnosed using a less definitive, non-MRI procedure.

Because MRI portrays soft tissue with such diagnostically-useful clarity, it is relied upon frequently for revealing abdominal abnormalities-mid-field scanners are clearly superior to high-field scanners in this regard-and a wide variety of other ills as diverse as malfunctioning temporomandibular joints (TMJs) in the jaw, pinched nerves in the spinal column, heart disease and multiple sclerosis. (Nothing is superior to MRI for revealing MS.) From the beginning, of course, one of the great strengths of MRI has been its ability to reveal tumors.

The second largest application for MRI at present is musculoskeletal disease. Orthopedic physicians regularly refer patients for MRIs for a wide variety of conditions. That's why you hear so much, for example, about professional athletes getting MRI scans. Many MRIs have a new development of a number of specialized MRI diagnostic methods used in sports medicine. These have led the way, for example, in providing anatomical motion studies. These studies enable technologists to electronically sequence a series of MRI images to create an accurate portrayal of how a malfunctioning joint in a patient is working dynamically. Individual MRI images reveal static conditions, just as a photo snapshot reveals a person's likeness just for an instant of time, but misses the facial expression that occurred a second or two earlier and the one that followed immediately after. A dynamic portrayal of a joint helps a physician understand how a particular joint-a shoulder, a knee, a neck or a TMJ-functions in "real life." Incidentally, open-environment MRI scanners are clearly superior for these motion studies as they provide the space required for a patient to move their arm, leg or neck through a wide range of positions.

Magnetic resonance angiography (MRA) is a well-utilized procedure that will only increase in use by cardiologists in the future. Although CAT scans are better able to show calcified plaque that has built up in an artery, physicians will increasingly turn to MRA in the future to reveal the presence and severity of soft atherosclerotic plaque. In other words, it will reveal newer, more recent plaque which has formed, enabling physicians to view the extent of artery disease more accurately and to treat that disease more appropriately.

Nothing is superior to an MRI for imaging breast implants. It shows the implants much more clearly than other modalities and it has the added advantage of not using X-rays, a particular concern when imaging the breast. MRI is also superior to ultrasound, X-ray mammograms or CAT scans when it comes to revealing malignancies in very dense breasts. This is still a developing area for MRI, one which will become much more dominant in the future.

The MRI applications mentioned above are just a small portion of the applications for which MRI is the modality of choice. If you have further questions, discuss them with your physician or speak with a radiologist who specializes in MRI. MRI is still a developing modality whose diagnostic power is becoming more and more appreciated with time. Already, it has replaced a great number of X-ray-based procedures and it is certain to replace even more in the future.