DefinitionAn abdominal MRI (magnetic resonance imaging) scan is a 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.
Alternative NamesNuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen
How the test is performedYou may be asked to wear a hospital gown or clothing without metal fasteners (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images.You will lie on a narrow table, which slides into a large tunnel-shaped scanner.Some exams require a special dye (contrast). The dye is usually 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 most often lasts 30-60 minutes, but may take longer.
How to prepare for the testYou may be asked not to eat or drink anything for 4 - 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, or your doctor may suggest an "open" MRI, in which the machine is not as close to the body.Before the test, tell your health care provider if you have:Brain aneurysm clipsCertain types of artificial heart valvesHeart defibrillator or pacemakerInner ear (cochlear) implantsKidney disease or dialysis (you may not be able to receive contrast)Recently placed artificial jointsCertain types of vascular stentsWorked 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:Pens, pocketknives, and eyeglasses may fly across 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 before the scan.
How the test will feelAn MRI exam causes no pain. If you have difficulty lying still or are very nervous, you may be given a medicine to relax you. Too much movement can blur MRI images and cause errors.The table may be hard or cold, but you can request a blanket or pillow. The machine produces 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 that you can use to help the time pass.There is no recovery time, unless you were given a medicine to relax. After an MRI scan, you can resume your normal diet, activity, and medications.
Why the test is performedAn abdominal MRI provides detailed pictures of the belly area from many different views. It is often used to clarify findings from previous x-rays or CT scans.This test may be used to diagnose or evaluate:Cancer and tumorsBlood flow in the abdomenBlood vessels in the abdomenThe cause of abdominal pain or swellingThe cause of abnormal blood test results, such as liver or kidney problemsLymph nodes in the abdomenMRI can distinguish tumors from normal tissues and can help the doctor determine the tumor's size, severity, and spread. This is called staging.MRI is sometimes used to avoid the dangers of angiography, repeated radiation exposure, iodine-related allergic reactions.
What abnormal results meanAn abnormal result may be due to:AbscessAcute tubular necrosisCancerEnlarged spleen or liverGallbladder or bile duct problemsGallstones, bile duct stonesHemangiomas, or othersHydronephrosis (kidney swelling from the backflow of urine)Kidney infectionKidney damageLymphadenopathy (abnormalities of the lymph nodes)Obstructed vena cavaPancreatic cancerPortal vein obstruction (liver)Renal arterial obstructionRenal vein thrombosisTransplant rejectionTumor of the gallbladderAdditional conditions under which the test may be performed:Abdominal aortic aneurysmAcute renal failureAdenomyosisAtheroembolic renal diseaseCarcinoma of the renal pelvis or ureterChronic renal failureCystinuriaHydatidiform moleInjury of the kidney and ureterInsulinomaIslet of Langerhans' tumorMedullary cystic diseaseMultiple endocrine neoplasia (MEN) IIMultiple endocrine neoplasia (MEN) INephrolithiasisOvarian cancerPheochromocytomaSkin lesion of histoplasmosis
What the risks areMRI contains no radiation. To date, 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 to the substance rarely occur. However, gadolinium can be harmful to patients with kidney problems who require dialysis. If you have kidney problems, please tell your health care provider before the test.The strong magnetic fields created during an MRI can cause heart pacemakers and other implants to not work as well. It can also cause a piece of metal inside your body to move or shift.
ReferencesPickhardt PJ. Diagnostic imaging procedures in gastroenterology. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 135.