Magnetic resonance imaging (MRI) is a safe and painless test that produces clear, cross-sectional or three-dimensional images of the body’s tissues, even through bone and other obstructions. Because of its safety and clarity, the MRI is a valuable tool that can aid in the diagnosis of a wide range of conditions, including injuries and diseases that affect the organs and glands of the digestive system (e.g., pancreas, liver).

MRI is used to detect abnormalities or problems in nearly every part of the body including:

• Abdomen
• Musculoskeletal system
• Blood vessels
• Head and brain
• Heart and chest

Typically, an MRI test is an outpatient procedure performed at a hospital or clinic. Patients should closely follow their physician’s recommendations in preparing for the test, and all patients will be asked to remove all jewelry beforehand.

During MRI, the patient is placed on a long bed that slides into the MRI chamber. Once inside the chamber, the patient must remain still for the duration of the procedure. Patients may be instructed to hold their breath at times. The MRI equipment will record multiple images of the target site on film. After receiving the radiology report, the physician will be more prepared to confirm a diagnosis or prescribe further tests and treatments.

Because the MRI test relies on a large magnetic field, certain people should avoid the test. These include patients with implanted pacemakers and implantable cardioverter defibrillators (ICDs). Patients with certain other medical implants should consult with a physician to find out when an MRI is permitted. In all cases, patients should inform the physician or technician of any tattoos or metal objects present in their bodies. Also, pregnant women should generally avoid MRI tests because the risk to the developing fetus is unknown. However, there may be some instances when an MRI is warranted in pregnant patients.

Patients who are nervous in small spaces may wish to ask their physician about the possibility of receiving a sedative during the procedure, which may take up to one hour or longer in a rather tight space. Using a less-enclosed type of MRI machine may be another option. If patients receive a sedative, then they will need someone to drive them home after the test. Otherwise, patients are free to go about their daily activities after the test is completed.

The magnetic resonance imaging (MRI) test uses a powerful magnetic field to create images of structures and organs within the body. It is a safe and noninvasive test that can help physicians diagnose a wide range of diseases and conditions without subjecting the patient to needles, radiation or radioactive isotopes. MRI can reveal tumors and functional disorders that affect digestive system organs, such as the liver and pancreas. In some cases, an MRI is performed to gain additional information after another imaging test, such as an ultrasound or computed axial tomography (CAT) scan, reveals a problem.

An MRI works by placing the patient in a chamber surrounded by a magnetic field. The center (nucleus) of atoms in the patient’s body responds to the magnetic force in characteristic ways, allowing a computer to produce clear, cross-sectional or three-dimensional images of the patient’s internal structures and organs.

MRI produces clear images that can allow physicians to locate and identify the cause of pain, inflammation or bleeding in tissues, organs and glands of the abdomen. The images are so detailed that they allow physicians to detect problems in organ function and even the smallest tears and injuries to ligaments and muscles that cannot be seen with x-rays.

Other conditions revealed by MRI examination include:

• Eye or inner-ear tissue abnormalities
• Damage caused by heart attack or heart disease
• Blood vessel plaques and blockages
• Functional disorders of organs, such as the lungs, liver, pancreas, kidney and spleen
• Strokes and chronic disorders of the nervous system
• Brain abnormalities in patients with dementia
• Diseases of the pituitary gland
• Reproductive system and bladder problems
• Various forms of cancer

Sometimes MRI involves injection of a contrast medium (dye) into a vein that increases the clarity of the images by making the body’s tissues more responsive to the machine’s magnetic and radio waves.

Magnetic resonance imaging (MRI) technology is used to help diagnose several gastrointestinal (GI) disorders that affect abdominal organs, such as the liver, pancreas or colon. Disorders that may be diagnosed using this technology include:

• Arterial disorders. Arteries that carry blood to the digestive tract and kidneys may be examined with a form of MRI known as magnetic resonance angiography (MRA).
  
  
• Cirrhosis of the liver. Condition in which scar tissue builds up and prevents blood from flowing through the liver, preventing the organ from functioning properly. An MRI may be scheduled to provide a visual examination of the liver.
  

  

• Colon disorders. MRI can be used to help diagnose conditions that affect the colon, the part of the large intestine that runs from the cecum to the rectum. MRI is also sometimes used in virtual colonoscopy (VC), which uses x-rays and computers to produce two- and three-dimensional images of the colon from the lowest part (rectum) to the lower end of the small intestine.  Conditions that may be detected in this way include polyps, diverticulosis and colorectal cancer.
  

  

• Fecal incontinence. A condition in which patients cannot control their bowel movements. MRI may be used to visually evaluate the anal sphincter, a ring of muscle that contracts to close the anus.
  
  
• Gallstone disease. Gallstones form in the gallbladder or bile ducts of the liver. They are made up of cholesterol and bile pigment, or a combination of the two. A test called magnetic resonance cholangiopancreatography (MRCP) uses MRI to create images of the bile and pancreatic ducts. Any abnormalities that are found may be further evaluated or treated with a technique called endoscopic retrograde cholangiopancreatography (ERCP), which uses a special endoscope to remove the stones.
  

  

• Intestinal ischemia. A variety of disorders that involve insufficient blood flow to the small intestine, the colon, or both. MRI of the abdomen may help diagnose this condition.
  
  
• Liver cancer and cholangiocarcinoma (cancer of the bile ducts). MRI technology can be use to create sectional views of the body in different planes and to reconstruct images of the biliary tree (the network of tubes and ducts that carry bile from the liver to the duodenum) and the arteries and veins of the liver.
  
  
• Nausea and vomiting. MRI scans of the GI tract, abdomen or brain may be used to uncover abnormalities that may be the source of these symptoms.
  
  
• Pancreatitis. Inflammation of the pancreas marked by swelling. In some cases, the pancreatic tissue may become damaged. An MRI may be performed to visually examine the pancreas for signs of this disease.
  
  
• Crohn's disease. An inflammatory bowel disease that causes deep tissue irritation and inflammation and can occur throughout the GI system. It most commonly occurs in the ileum (last part of the small intestine) and the cecum (first part of the large intestine). Although computed axial tomography (CAT) scans are more commonly used in diagnosis, MRI provides the highest quality images for Crohn’s disease that affects the perianal region.
  
  
• Primary sclerosing cholangitis (PSC). A condition that involves inflammation and scarring of the bile ducts inside and outside the liver. Because the bile ducts become damaged, they prevent bile from flowing out of the liver. This buildup of bile can lead to cirrhosis and liver failure. PSC is diagnosed through a technique called cholangiography, which involves injecting dye into the bile ducts and taking an x-ray. Cholangiography is sometimes performed using MRI scans.

Almost every part of the body may be studied with magnetic resonance imaging (MRI). The clear pictures obtained from an MRI often provide physicians with information not available through other diagnostic tests such as x-rays, and in some cases may even eliminate the need for exploratory surgery.

To gather information about various conditions affecting the body, including the gastrointestinal system, physicians may use several types of MRI scanners including:

• Standard MRI. This scanner resembles a long cylinder with a narrow tube in the center. A patient lies on a moveable bed and the whole body is inserted inside the tube. Although this machine may be confining for some people, it produces the clearest images.
  
  
• Short-bore MRI. This scanner is similar to the standard, except only half the size. Depending on which areas of the body are being tested, patients position their bodies so that the part being scanned lies within the tube. People that experience anxiety in enclosed spaces may prefer this scanner.
  
  
• Open MRI. This scanner resembles a bagel sliced in half and is a good option for obese or claustrophobic patients because there is additional room inside the machine. However, the images it produces are not as detailed as those of the other two MRI scanners.

Typically, the magnetic resonance imaging (MRI) test is an outpatient procedure performed at a hospital or clinic. Patients should closely follow their physician’s recommendations in preparing for the test. Usually, patients will be allowed to eat without restrictions and to take their normal medications. Once at the facility, patients may be asked to change into a gown or to wear clothing without fasteners, such as a sweatshirt and sweatpants.

It is important for the patient to remove all personal metal objects (e.g., rings, earrings, necklaces) prior to the test. In fact, patients may want to leave these objects at home on the day of the test. Additionally, there should be no metal objects inside the room in which the MRI is being performed.

Certain types of implanted medical devices rule out the use of MRI. These objects generally include (but are not limited to):

• Pacemakers
• Implantable cardioverter defibrillators (ICDs)
• Artificial hips, knees and other joints (in some cases)
• Inner ear (cochlear) implants
• Titanium implants in the mouth
• Aneurysm clip of the brain
• Neuromuscular stimulators
• Implanted drug infusion pump, such as an insulin pump

MRI may be allowed with other types of medical devices, such as artificial joints and certain types of stents and heart valves. Sometimes a specified period of time must have elapsed. Such patients should inform the physician and get clearance before an MRI. If patients suspect that they have a metal device or fragment (such as from an injury) inside their body, an MRI might not be an option.

Sometimes MRI involves injection of a contrast medium (dye) into a vein in the arm or hand shortly before the procedure. This dye can increase the clarity of the images by making the body’s tissues more responsive to the machine’s magnetic and radio waves.

The magnetic resonance imaging (MRI) chamber is a relatively tight space, and individuals undergoing a scan are required to lie still for up to one hour, and sometimes as long as two hours. Some people may feel uncomfortable or claustrophobic in this environment. Sometimes radios are available to help patients relax, but those who become very anxious in small spaces may want to discuss with their physician the possibility of receiving a mild sedative before the procedure. Newer “open” MRI scanners have been designed to increase patients’ comfort levels, but the images they produce are subject to more background interference and are not as clear.

During MRI, the patient is placed on a long bed that slides into the MRI chamber. The individual may be given a hand–held buzzer to stop the test in case of some type of emergency. Once inside the chamber, the patient should relax and lie still for the duration of the procedure. Patients may be instructed to hold their breath at times. The MRI equipment will make many different types of noises during the scan as it takes multiple views of the target site. These noises are a normal part of the MRI procedure. A nurse or technician will periodically make sure that the patient is comfortable and able to continue.

Those taking the test should be able to leave immediately following the MRI with no side effects. However, if a sedative is administered, patients will be monitored until the effects of the sedative have passed. They will then need a friend or relative to drive them home.

Results of the test are recorded on film. After receiving the radiology report, the physician will be more prepared to confirm a diagnosis or prescribe further tests and treatments.

Researchers recently devised a method that allows for remote MRIs in which a technician controls the parameters of the test and the MRI scanner from a remote location. This technique is currently being studied on cardiac patients.

Historically, pregnant women have been instructed to avoid having a magnetic resonance imaging (MRI) test unless absolutely necessary because risk to the developing fetus was unknown. However, recent research indicates that MRI may be a safer and more effective alternative to other imaging tests when certain conditions (e.g., appendicitis) are suspected in women who are pregnant.

Patients with tattoos or permanent makeup are encouraged to consult with their physician before an MRI is performed. These patients might feel some mild discomfort or a burning feeling on their skin due to a reaction between iron oxide or other metallic substances commonly found in the darker inks of the tattoo and the magnetic field generated during the test. Furthermore, large or very dark tattoos can also cause “artifacts,” or false shadows to appear on the film produced from the test.

If the MRI involves injection of a contrast medium, there is the possibility of a reaction. An individual may experience nausea, headache or pain at the site of injection.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about magnetic resonance imaging (MRI):

1. Why is an MRI test a good option for diagnosing my disorder?
   
   
2. What information will an MRI provide regarding my condition?
   
   
3. How should I prepare for my MRI?
   
   
4. What can I expect during my MRI?
   
   
5. Will I experience any pain or discomfort during my MRI?
   
   
6. Will I require a sedative before my MRI?
   
   
7. I tend to be a little claustrophobic. Which type of MRI is best for me?
   
   
8. Should I arrange for transportation home from my MRI?
   
   
9. Will I be able to resume my normal daily activities after my MRI?
   
   
10. What other tests, if any, will follow my MRI?