What Is Magnetic Resonance Enterography?

What to expect when undergoing this test

Magnetic resonance (MR) enterography is a painless, noninvasive, and radiation-free medical imaging test used to diagnose problems in your small intestine. A specialized form of magnetic resonance imaging (MRI), the test provides detailed images of your small intestine through the use of a strong magnetic field.

Purpose of Test

With MR enterography, your doctor can obtain high-resolution images of your small intestine to help with disease detection, diagnosis, and treatment monitoring.

The procedure is done in an MRI machine, which uses powerful magnets to produce a strong magnetic field that helps to create detailed computerized pictures.

MR enterography is performed with a contrast material, which is a liquid that helps to improve the quality of images. Contrast material is administered orally and/or intravenously.

Since there is no ionizing radiation involved in MR enterography, this procedure is typically the preferred approach in the evaluation of young people with inflammatory bowel disease and those with certain types of inflammatory bowel disease. That’s because MR enterography can help to reduce the lifetime exposure to ionizing radiation from X-rays.

Diagnosis

Doctors use MR enterography to diagnose a number of medical conditions affecting the small intestine, including inflammatory bowel diseases (such as Crohn’s disease).

In addition, MR enterography can identify the following problems:

  • Inflammation
  • Internal bleeding
  • Vascular abnormalities
  • Tumors
  • Abscesses
  • Small tears in the intestinal wall
  • Small bowel polyps
  • Bowel obstructions

Monitoring

MR enterography may also be used to track how well certain treatments are working, and to detect any complications.

Differences and Limitations

Unlike a computed tomography (CT) scan (sometimes referred to as computerized axial tomography or CAT scan), MR enterography does not use X-rays to produce images.

Additionally, the contrast material used in MR enterography is generally considered less likely to produce an allergic reaction than the iodine-based contrast materials used for conventional X-rays and CT scanning.

In many cases, MR enterography provides a clearer differentiation between abnormal and normal tissue (compared to conventional x-rays and CT scanning).

However, MR enterography takes considerably longer to perform than CT enterography (30 to 45 minutes, compared to two to four minutes).

One of the limitations of MR enterography is that patient movement may affect the quality of images produced. This means that high-quality images are only achieved when the person remains completely still and adheres to breath-holding instructions during the image-recording process. Because people with anxiety may find it difficult to keep still, it’s often recommended that such people receive a sedative prior to undergoing MR enterography.

Another limitation of MR enterography is that particularly large individuals may not fit into the opening of some MRI machines.

Risks and Contraindications

Although MR enterography does not use ionizing radiation, it does use a strong magnetic field. For this reason, it’s crucial to inform your healthcare team if you have any devices, implants, or metal in your body, or if you have worked with metal in the past.

People with certain implants cannot have this procedure, so be sure to notify your physicians prior to an MR enterography to be sure that it is safe for you.

The magnetic fields may cause some medical devices to malfunction. 

Here are several other things to consider prior to undergoing MR enterography:

  • It’s important to tell your radiologist if you have a history of kidney disease, have other health problems, or if you have undergone surgery or medical treatment recently. 
  • There is a very small risk of an allergic reaction when the contrast material is injected. These reactions are typically mild and easily alleviated with medication. Tell your healthcare team right away if you notice any allergic symptoms.
  • If you have any metal objects in your body (including shrapnel and bullets), alert your healthcare team.
  • While MR enterography isn’t known to harm fetuses, it’s recommended that pregnant women avoid undergoing any type of MRI exam as a precaution, particularly during the first trimester (unless medically necessary).
  • Patients with very poor kidney function and those requiring dialysis face the risk of a rare complication called nephrogenic systemic fibrosis due to the contrast material. If you have a history of kidney disease, you’ll need to undergo a test to assess whether your kidneys are functioning adequately.

Possible Disqualifications

Certain people should not undergo MR enterography. These include individuals with:

  • Cochlear (ear) implants
  • Certain types of clips used for brain aneurysms
  • Certain types of metal coils placed within blood vessels
  • Nearly all cardiac defibrillators and pacemakers

Certain people who have worked with metal in the past may not be able to undergo MR enterography.

Before the Test

In addition to informing your doctor of any health problems, recent surgeries, implants, foreign objects, medical devices, and history of working with metal, make sure to notify your healthcare team of any allergies before undergoing MR enterography. You should also let your doctor know if you are or could be pregnant.

If you have claustrophobia or anxiety, your physician may give you a prescription for a mild sedative prior to your MR enterography.

Here are some other questions to ask your doctor before your MR enterography:

  • Whether you need to stop taking any of your regular medicines or supplements before the procedure
  • When to stop eating and drinking before the exam, or if you should avoid certain foods 
  • What results to expect and what they mean
  • Any alternative tests or procedures you might want to consider

In general, it’s also essential to understand why you are undergoing MR enterography. If you have any questions or concerns about why you’re receiving this test, don’t hesitate to ask your doctor.

Timing

MR enterography takes about 45 minutes. However, in many cases, you’ll need to arrive two and a half hours prior to the exam in order to drink an oral contrast material. The oral contrast is often provided at 30-minute intervals.

During your check-in process, you’ll most likely be asked to fill out a safety form.

Location

MR enterography is often performed at hospitals or at imaging centers. Your doctor will inform you where your exam will take place.

Typically, the MRI unit is a large, cylinder-shaped tube surrounded by a circular magnet. During the exam, you’ll lie on a moveable examination table that slides into the center of the magnet.

What to Wear

When undergoing MR enterography, wear comfortable clothing and leave your jewelry at home. Once you arrive at your appointment, you’ll be asked to change into a hospital gown and lock up your belongings.

Cost and Health Insurance

Your MR enterography should be covered by your health insurance. Depending on your plan, you may have to pay a co-pay and/or coinsurance. Some insurance plans may require pre-authorization for MR enterography.

Food and Drink 

Instructions on eating and drinking prior to undergoing MR enterography tend to vary between facilities, so be sure to carefully read the instructions your facility gives you. Unless you’re told otherwise, continue taking your regular medications as usual.

What to Bring

If you have a medical device or implant, bring along any information you have about it to show your technologist prior to undergoing MR enterography.

You should also bring your ID and insurance card to the exam.

Other Considerations

If you’re planning to receive a sedative before your MR enterography, make arrangements for a ride home from the exam.

Since the MRI machine may produce loud noises, you may be given earplugs or headphones to wear during the exam. Many centers provide headphones as a matter of course to block the noise and so the technologist can speak to you during the procedure.

During the Test

Pre-Test

When you arrive at the facility, you'll be asked to change into a gown. Before your MR enterography, your healthcare team may review your health and medication history and check your heart rate, temperature, and blood pressure.

An IV will be started in your hand or arm. You may be asked to drink an oral contrast drink in timed intervals. A contrast agent may be administered through the IV. In some cases, you'll experience a cold sensation when the contrast enters your bloodstream. You might also get a metallic taste in your mouth.

You’ll lie flat on your back on a table that slides in and out of the scanner. In some cases, straps may be used to help hold stay in the correct position. The technologist will most likely put a pillow under your head and a cushion under your knees.

Throughout the Test

During the exam, you’ll be placed into the magnet of the MRI unit and the radiologist and technologist will carry out the procedure while working at a computer outside of the room. The scanner is well-lit and air-conditioned.

Most exams involve taking two or more sets of pictures, with each set lasting two to 15 minutes and showing a different part of your small intestine and the surrounding tissues. After the first set of pictures, your radiologist will look at the images to ensure that you have enough of contrast in your intestines. In some cases, you may have to walk around to help move the contrast through your intestines.

Please note that you may feel some warmth in the area of your body that's being scanned. This feeling is normal, but let your technologist know if it bothers you.

During the exam, your technologist may ask you to hold your breath at certain points. This helps to improve the quality of the images obtained.

Although you’ll be alone in the room during the MR enterography, you can talk to the technologist at any time.

Post-Test

After the test is complete, you may need to wait a few minutes while your healthcare team determines whether any additional images are needed.

Once all images are obtained, the exam table will be slid from the MRI tube. If you received an IV, the intravenous line will be taken out at this time.

If you had anesthesia, you will be taken to a recovery room after the exam. Otherwise, you can go home right away.

After the Test

It’s normal for people to feel slightly full or a bit nauseated for several hours after undergoing MR enterography. Some people may experience some cramping or diarrhea. If these symptoms don’t subside by the next day or are severe, however, make sure to consult your doctor.

In addition, there’s a very small risk of skin irritation at the site of IV tube insertion.

There are no post-exam dietary restrictions associated with MR enterography. You may continue with your usual eating and drinking routine after the procedure.

It should be noted that manufacturers of intravenous contrast suggest that mothers avoid breastfeeding their babies for up to 48 hours after receiving contrast medium. However, the American College of Radiology and the European Society of Urogenital Radiology state that it is safe to continue breastfeeding after receiving intravenous contrast.

Interpreting Results

After your MR enterography, a radiologist will analyze the images and send a report to your primary care provider or referring doctor. Your physician will then share these results with you.

While results generally take several days to come back, the wait time varies depending on the facility.

Follow-Up

If your MR enterography results aren’t normal, you may need additional imaging (such as a repeat MRI, a CT scan, or an X-ray) or other types of medical tests. Talk to your doctor about how to proceed in the event of abnormal results.

A Word From Verywell

Because waiting for test results can cause a great deal of anxiety, it’s important to take steps to ease your worries. Along with spending time with your loved ones, focus on enjoyable activities that keep your mind occupied. If you have any questions during the waiting period, don’t hesitate to reach out to your doctor or his/her staff.

View Article Sources
  • Allocca M, Fiorino G, Bonifacio C, et al. Comparative accuracy of bowel ultrasound versus magnetic resonance enterography in combination with colonoscopy in assessing Crohn's disease and guiding clinical decision-making. J Crohns Colitis. 2018. DOI: 10.1093/ecco-jcc/jjy093.
  • Taylor SA, Mallett S, Bhatnagar G, et al. Diagnostic accuracy of magnetic resonance enterography and small bowel ultrasound for the extent and activity of newly diagnosed and relapsed Crohn's disease (METRIC): a multicentre trial. Lancet Gastroenterol Hepatol. 2018;3(8):548-558. DOI: 10.1016/S2468-1253(18)30161-4.