Abdominal MRI
Alternative names:
magnetic resonance imaging - abdomen; MRI of the abdomen; NMR - abdomen; nuclear magnetic resonance - abdomen
How the test is performed:
The MRI scanner is in an area that has been shielded from outside magnetic fields. You are asked to lie on a narrow table that can slide inside a large tunnel-like tube within the scanner. The scanner creates a magnetic field around you, then pulses radio waves at the tissues in question. Several sets of images are usually required, each taking from 2 to 15 minutes. The complete scan takes about 1 hour; some scans take more than 90 minutes.
How to prepare for the test:
No preparatory tests, diets, or medications are usually needed. Occasionally you may be asked to fast for 4 to 6 hours prior to the scan. The colon may need to be cleaned (with preparations such as a laxative or an enema) before MRI of some abdominal structures. You must sign a consent form before the scan.
Because of the strong magnets, no metallic objects are allowed into the room. Items such as jewelry, watches, credit cards, and hearing aids can be damaged by the strong magnets. Pins, hairpins, metal zippers, and similar metallic items can distort the images. Frequent exposure to ferrous metals (such as a sheet-metal worker experiences) may make reading an MRI scan difficult. You may be required to wear a hospital gown, or you may be allowed to wear "sweats" or similar clothing without metal fasteners. You should take out any removable dental work just prior to the scan.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
How the test will feel:
There is no pain. You do not feel the magnetic field and radio waves. The primary discomfort is the claustrophobic feeling that some people 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. Usually you are given ear plugs to reduce the noise. A technologist observes you during the entire procedure, and may enter the room to speak (or may speak through an intercom in the scanner) with you.
Excessive movement can blur MRI images. If you have difficulty lying still or are very anxious, a sedative may be given. Medication may be given to reduce the activity of the intestines and minimize motion artifact (blurring of the images caused by movement, including intestinal peristalsis) during the scan of the abdomen. There is no recovery required (unless you have been sedated). After an MRI scan, you usually can resume normal diet, activity, and medications.
Why the test is performed:
MRI provides detailed pictures of soft tissues without obstruction by overlying bone. It is used to clarify findings from previous X-rays or CT scans, or may be recommended when the area to be scanned is obstructed by overlying bone or foreign bodies. It can show a wide area of the abdomen from multiple planes. MRI can reflect certain organ functions. It clearly shows lymph nodes and blood vessels, and is a noninvasive procedure that can evaluate blood flow.
MRI may be used in diagnosing abnormal growths. It can distinguish tumors or other lesions from normal tissues and can provide information for the staging (determination of the size, extent, and spread) of abdominal tumors. MRI is sometimes used to avoid the dangers of angiography or repeated exposure to radiation.
|
