MRI

Because of the strong magnets, certain metallic objects are not allowed into the room.

Items such as jewelry, watches, credit cards, and hearing aids can be damaged.
Pins, hairpins, metal zippers, and similar metallic items can distort the images.
Removable dental work should be taken out just prior to the scan.
Pens, pocketknives, and eyeglasses can become dangerous projectiles when the magnet is activated and should not accompany the patient into the scanner area.

Because the strong magnetic fields can displace or disrupt the action of implanted metallic objects, people with cardiac pacemakers cannot be scanned and should not enter the MRI area.

MRI also should not be used for people with metallic objects in their bodies, such as:

Inner ear (cochlear) implants
Brain aneurysm clips
Some artificial heart valves
Older vascular stents
Recently placed artificial joints

Sheet metal workers, or persons with similar potential exposure to small metal fragments, will first be screened for metal shards within the eyes with x-rays of the skull.

The patient will be asked to sign a consent form confirming that none of the above issues apply before the study will be performed.

A hospital gown may be recommended, or the patient may be allowed to wear a sweatsuit or similar clothing without metal fasteners.

How the test will feel:

There is no pain. The magnetic field and radio waves are not felt. The primary possible discomfort is the claustrophobic feeling that some experience from being inside the scanner. The table may be hard or cold, but you can request a blanket or pillow. The machine produces loud thumping and humming noises during normal operation. Ear plugs are usually given to the patient to reduce the noise.

A technologist observes the patient during the entire procedure and may be spoken to through an intercom in the scanner. Some MRI scanners are equipped with televisions and special headphones to help the examination time pass.

Excessive movement can blur MRI images and cause certain artifacts. If the patient has difficulty lying still or is very anxious, an oral or intravenous sedative may be given. There is no recovery time, unless sedation was necessary. After an MRI scan, you can resume normal diet, activity, and medications.

Why the test is performed:

An MRI can provide additional imaging information for the clinician based upon its superior tissue contrast resolution. Combined with other imaging methods, a more definitive diagnosis can be given in the work up of a patient's disease.

Sequences performed with intravenous contrast may provide additional data about the blood vessels within masses.

An MRA, or magnetic resonance angiogram, is a special type of MR that creates three-dimensional reconstructions of vessels containing flowing blood and is often utilized when conventional angiography cannot be performed due to renal failure or other contraindications.