NMR - abdomen
Key points
- A noninvasive procedure that uses powerful magnets and radio waves to construct pictures of the abdomen and its organs.
- Since MRI makes use of radio waves very close in frequency to those of ordinary FM radio stations, the scanner must be located within a specially shielded room to avoid outside interference.
- No preparatory tests, diets, or medications are usually needed, unless the colon needs to be cleansed (with preparations such as a laxative or an enema).
- The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust.
Alternative names
Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen; Abdominal MRI
Definition
A noninvasive procedure that uses powerful magnets and radio waves to construct pictures of the abdomen and its organs.
Magnetic resonance imaging (MRI) produces pictures of the inside of the abdomen without exposure to ionizing radiation (X-rays).
How the test is performed
Since MRI makes use of radio waves very close in frequency to those of ordinary FM radio stations, the scanner must be located within a specially shielded room to avoid outside interference. The patient will be asked to lie on a narrow table which slides into a large tunnel-like tube within the scanner. In addition, small devices may be placed around the head, arm, or leg, or adjacent to other areas to be studied. These are special body coils which send and receive the radio wave pulses, and are designed to improve the quality of the images. If contrast is to be administered, an IV will be placed, usually in a small vein of the hand or forearm. A technologist will operate the machine and observe you during the entire study from an adjacent room.
Several sets of images are usually required, each taking from 2 to 15 minutes. A complete scan, depending on the sequences performed, and need for contrast enhancement may take up to one hour or more. Newer scanners with more powerful magnets utilizing updated software and advanced sequences may complete the process in less time.
How to prepare for the test
No preparatory tests, diets, or medications are usually needed, unless the colon needs to be cleansed (with preparations such as a laxative or an enema). An MRI can be performed immediately after other imaging studies. Depending on the area of interest, the patient may be asked to fast for 4 to 6 hours prior to the scan.
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, and 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 . The patient will be asked to sign a consent form confirming that none of the above issues apply before the study will be performed.
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.