Abdominal MRI scanNuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen
An abdominal magnetic resonance imaging (MRI) scan is an imaging test that uses powerful magnets and radio waves to create pictures of the inside of the belly area. It does not use radiation (x-rays).
Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of images.
How the Test is Performed
You may be asked to wear a hospital gown or clothing without metal zippers or snaps (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images.
You will lie on a narrow table. The table slides into a large tunnel-shaped scanner.
Some exams require a special dye (contrast). Most of the time, the dye is given before the test through a vein (IV) in your hand or forearm. The dye helps the radiologist see certain areas more clearly.
During the MRI, the person who operates the machine will watch you from another room. The test lasts about 30 to 60 minutes, but it may take longer.
How to Prepare for the Test
You may be asked not to eat or drink anything for 4 to 6 hours before the scan.
Tell your doctor if you are afraid of close spaces (have claustrophobia). You may be given a medicine to help you feel sleepy and less anxious. Your health care provider may also suggest an open MRI, in which the machine is not as close to your body.
Before the test, tell your provider if you have:
- Artificial heart valves
- Brain aneurysm clips
- Heart defibrillator or pacemaker
- Inner ear (cochlear) implants
- Kidney disease or dialysis (you may not be able to receive contrast)
- Recently placed artificial joints
- Certain types of vascular stents
- Worked with sheet metal in the past (you may need tests to check for metal pieces in your eyes)
Because the MRI contains strong magnets, metal objects are not allowed into the room with the MRI scanner:
- Items such as jewelry, watches, credit cards, and hearing aids can be damaged.
- Pens, pocketknives, and eyeglasses may fly across the room.
- Pins, hairpins, metal zippers, and similar metallic items can distort the images.
- Removable dental work should be taken out just before the scan.
How the Test will Feel
An MRI exam causes no pain. You may get medicine to relax you if you have a problem lying still or are very nervous. Moving too much can blur MRI images and cause errors.
The table may be hard or cold, but you can ask for a blanket or pillow. The machine makes loud thumping and humming noises when turned on. You can wear ear plugs to help reduce the noise.
An intercom in the room allows you to speak to someone at any time. Some MRIs have televisions and special headphones to help you pass time.
There is no recovery time, unless you were given a medicine to help you relax. After an MRI scan, you can go back to your normal diet, activity, and medicines.
Why the Test is Performed
An abdominal MRI provides detailed pictures of the belly area from many views. It is often used to clarify findings from earlier x-rays or CT scans.
This test may be used to look at:
- Blood flow in the abdomen
- Blood vessels in the abdomen
- The cause of abdominal pain or swelling
- The cause of abnormal blood test results, such as liver or kidney problems
- Lymph nodes in the abdomen
- Masses in the liver, kidneys, adrenals, pancreas, or spleen
MRI can distinguish tumors from normal tissues. This can help the doctor know more about the tumor such as size, severity, and spread. This is called staging.
MRI avoids the dangers of angiography, such as too much radiation exposure and allergic reactions to iodine. In some cases it can give better information about masses in the abdomen than CT.
What Abnormal Results Mean
An abnormal result may be due to:
- Acute tubular necrosis
- Enlarged spleen or liver
- Gallbladder or bile duct problems
- Gallstones, bile duct stones
- Hydronephrosis (kidney swelling from the backflow of urine)
- Kidney infection
- Kidney damage
- Lymphadenopathy (abnormalities of the lymph nodes)
- Obstructed vena cava
- Pancreatic cancer
- Portal vein obstruction (liver)
- Renal arterial obstruction
- Renal vein thrombosis
- Transplant rejection
- Tumor of the gallbladder
Additional conditions under which the test may be performed:
- Abdominal aortic aneurysm
- Atheroembolic renal disease
- Carcinoma of the renal pelvis or ureter
- Injury of the kidney and ureter
- Islet of Langerhans tumor
- Medullary cystic disease
- Multiple endocrine neoplasia (MEN) I
- Multiple endocrine neoplasia (MEN) II
MRI does not use ionizing radiation. No side effects from the magnetic fields and radio waves have been reported.
The most common type of contrast (dye) used is gadolinium. It is very safe. Allergic reactions rarely occur. However, gadolinium can be harmful to people with kidney problems who need dialysis. Tell your provider before the test if you have kidney problems.
The strong magnetic fields created during an MRI can cause heart pacemakers and other implants not to work as well. The magnets can also cause a piece of metal inside your body to move or shift.
Kim DH, Pickhard PJ. Diagnostic imaging procedures in gastroenterology. In: Goldman L, Schafter AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 135.
Wilkinson ID, Graves MJ. Magnetic resonance imaging. In: Adam A, Dixon AK, Gillard JH, et al. eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 6th ed. New York, NY: Churchill Livingstone; 2014:chap 5.
Review Date: 10/22/2014
Reviewed By: Jason Levy, MD, Northside Radiology Associates, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.