Body Parts Small Bowel

Small Bowel MRI

Small bowel MRI scans can help identify the causes of intestinal problems, and can reveal inflammation, tumours, Crohn's disease, and more.
Written by
Chelsea Okonkwo

Small Bowel MRI: What Can It Show and Why You Should Get One

Are you interested in learning about an MRI small bowel scan, including what to expect during the procedure, how long it will take, what it can show you, and whether it is the right scan for your symptoms? We answer all your burning questions in this complete guide to small bowel MRI scans.  

If you're not sure which imaging test to book for the correct diagnosis of your unique symptoms, consider booking a consultation for £50 to receive tailored education and guidance from an expert clinician.  

What and where is the small bowel?

The small bowel, also called the small intestine, is a narrow, tube-like organ that can stretch up to three or four times your height in length. It is compactly folded to fit inside the lower abdomen (precisely around the belly button area), connecting the stomach to the large intestine (also referred to as the large bowel or colon).

So, what does the small bowel do? After food is partially digested in the stomach, it moves to the small bowel. Here, the digestion process is completed, and nutrients—such as fats, carbs, protein, vitamins, and minerals—and water are absorbed into the bloodstream to be transported throughout the body to where they are needed. The indigestible portion of the food proceeds to the large intestine, where it is processed as solid waste and passed out of the body.

When there’s a problem with the small bowel, it can lead to nutritional deficiencies and may manifest as symptoms such as:

  • Bloating 

  • Distended (swollen) stomach

  • Severe abdominal pain or cramping

  • Nausea

  • Vomiting

  • Diarrhoea or severe constipation

  • Rapid heart rate

  • Unexplained weight loss

  • Blood in stool

In this case, a doctor may order some blood tests, a urine or stool test, and an imaging test such as an MRI scan for bowel problems to identify the specific cause(s) of the symptoms (e.g., inflammation, bleeding, infection, blockage, etc.) and determine the most appropriate treatment options based on the diagnosis.

What is the MRI small bowel procedure?

Magnetic resonance imaging (MRI) is a painless, non-invasive test that uses a powerful magnetic field and radio waves to generate highly detailed images of the body’s internal organs, bones and soft tissues. An MRI on small bowel procedure is also called magnetic resonance enterography (MRE); it is used to obtain clear pictures of the three distinct regions of the small intestines—the duodenum, jejunum, and ileum—along with their surrounding structures.

The scan is performed inside a long, tube-shaped machine that is open at both ends. Once inside, it generates a strong magnetic field and radio waves to create images of the small bowel.

If you are claustrophobic, being inside the enclosed space of an MRI scanner might be uncomfortable for you. In that case, we advise consulting with your scan clinician on the best way(s) to manage your symptoms, such as using music as a distraction, wearing an eye mask, or opting for an open MRI, which provides a more spacious environment and is less noisy.

Now, to address the pressing questions you may have regarding the scan.

How should I prepare for an MRI bowel scan?

You may be asked to avoid consuming food or drinks for up to 6 hours before your procedure. If you are taking medications, you can do so using no more than 8 ounces of plain water. 

What happens during a small bowel MRI scan?

  • You will be asked to change into a hospital gown and remove any jewellery, medication patches, wristwatches, belts or metallic objects. 

  • You may be asked to drink up to 1.5 litres of a small bowel MRI prep drink (called Mannitol or VoLumen) about 45 to 60 minutes before the scan starts. It is an oral contrast media used to define the small bowel. You may feel full or have to go to the bathroom - this is common and normal. 

  • An MRI technologist (a person trained to capture MRI images) will help you lay on an elevated, motorised bed in the exam room. They might provide a pillow or straps to keep your body in the correct position for the scan. It is also normal to have a specialised pad placed on your abdomen. The pad contains coils which produce waves that will allow the MRI machine to capture the necessary images of your intestine.

  • The MRI scanner is quite noisy, so you will be asked to wear earplugs or headphones to prevent damage to your hearing. And since you will be left alone in the exam room, you might be given an emergency buzzer or squeeze ball to hold. You can communicate with the radiographer through an inbuilt microphone and speaker system, or they may come in person to check on you. 

  • The technologist will insert a cannula or IV line (a thin, flexible tube) into your vein and administer two rounds of injections. The first injection is an MRI dye, a gadolinium-based contrast agent, which will enhance the visibility of specific tissues, blood vessels, and lymph nodes in your small bowel. The second is a muscle relaxant (called buscopan or glucagon) that prevents blurry images by slowing the involuntary movements of smooth muscles in your gastrointestinal (GI) tract. 

It is not uncommon to be scanned before and after the contrast dye is administered. This is usually done to establish a baseline (i.e., an initial observation), especially if the technologist is interested in comparing before and after images for a more accurate assessment of changes or abnormalities.

  • The MRI technologist will watch you through a window from an adjacent room, where they access the images generated by the scanner on their computer. They may instruct you to hold your breath several times to avoid blurred or distorted images caused by breathing movements. 

What happens after the scan? 

The scan is completed once the technologist decides they have all the necessary views or images. They will then remove the IV. You may feel dizzy standing up, but it will wear off almost instantly..

No special precautions are necessary post-scan. You can resume your daily activities and normal diet without any trouble. However, the small bowel prep drink side effects may include nausea, diarrhoea, and cramping, which you may experience within a few hours after the scan. These symptoms should resolve if you drink plenty of water and take pain relief. If they persist into the following day, contact your doctor.

The technologist will transfer your small bowel MRI images to a radiologist, who will carefully examine them and create a report of their findings. The report will be provided to you within seven working days when you book with Scan.com.

Are there any risks involved?

Due to the use of a strong magnetic field, an MRI scan is not safe for people with implanted medical devices made with metallic materials, such as a cardiac pacemaker or defibrillator. Additionally, the gadolinium-based contrast agent poses a risk for people on dialysis or with severe kidney problems, those with allergies to the contrast material, and pregnant women. 

Alternative tests such as an ultrasound or computed tomography enterography (CTE) scan may be used to obtain detailed images of the bowel in cases where MRI is contraindicated (i.e., not suitable for use). If you are unsure whether a small bowel MRI is the right test for you, book a consultation for £50 to match with a clinician who’ll call to discuss your medical history, educate you on the benefits and risks of the available options, and offer a no-obligation referral to the scan that’s most suitable for your unique needs. If you do decide to book a scan, your fee will be automatically discounted by £50. 

How long does a small bowel MRI take?

An MRE scan can take anywhere from 15 to 30 minutes to complete. However, you may be asked to arrive approximately 2.5 hours before your scheduled appointment to be adequately prepared. The entire process, including the uptake or administration of contrast agents, other necessary preparations, and the scan itself, can take up to 3 hours.

What can a small bowel MRI scan show?

A small bowel MRI can visualise various structures within the abdomen, including:

  • Folds of the intestines: It provides a clear and detailed visualisation of the small intestine's loops and folds, even as there's some peristaltic (involuntary contraction) movement going on.

  • Bowel wall: It can show the thickness and integrity of the bowel wall, which is crucial for detecting abnormalities such as inflammation, bleeding, scarring, abscesses (pus-filled pockets), potentially cancerous tumours (solid masses), strictures (narrowing of the wall), or ischemia (insufficient blood flow to the intestine).

  • Adjacent organs (only partially): Certain parts of nearby organs, such as the liver, pancreas, gallbladder, kidneys, and spleen, may be captured by a small bowel MRI. They may provide additional information about abnormalities in the bowel.

  • Mesentery: An MRI bowel scan can show the mesentery, a membrane that attaches the small intestine to the abdominal wall. The mesentery contains the blood vessels and lymph nodes that support the small bowel, making it easier for an MRI to detect vascular abnormalities that are suggestive of or actively contributing to problems in the bowel.

Does a small bowel MRI show the stomach?

While a small bowel MRI scan primarily focuses on imaging the small intestine, it can occasionally visualise a portion of the stomach, particularly where the duodenum (top part of the small bowel) exits from. If there's a need for a thorough investigation of the stomach due to an abnormality discovered in the small bowel or based on a suspected diagnosis, a dedicated stomach or abdominal MRI scan may be more appropriate. 

What does a small bowel MRI look for?

Here are some of the conditions and possible diagnoses that can be assessed through small bowel MRI:

  1. Inflamed small bowel MRI may find:

  • Crohn's disease: An MRI scan is highly accurate, with a sensitivity rate of over 90%, for detecting Crohn's disease, an inflammatory bowel disease (IBD) that commonly affects the small intestine. It can identify areas of active inflammation, abnormal thickness, strictures (narrowing), and oedema (swelling) and detect complications of the disease. For people who have already been diagnosed with Crohn’s, an MRI may be used routinely to monitor its activity and how it is responding to treatment. 

The second type of IBD, to which an MRI is highly sensitive, is ulcerative colitis, which is seen only in the large intestine.

  • Small bowel obstruction: Whether a blockage in the small intestine is caused by a tumour, chronic constipation, swallowed foreign object or diverticulosis (a condition where pouches form and push outward from inside the bowel wall), inflammation is likely to occur. An inflamed small bowel MRI can determine the location of small bowel obstructions and show the extent of damage caused. 

  • Enteritis (inflammation of the small intestine): An MRI scan can detect the signs of enteritis, an inflammatory disease caused by viral or bacterial infections.

  1. Bowel Cancer MRI may find: 

  • Small bowel tumours: It can detect small bowel tumours, which may be malignant (cancerous) or benign (non-cancerous). 

Can MRI detect bowel cancer?

Yes! MRI can detect tumours inside the small bowel. However, not all tumours are cancerous. Small bowel cancer itself is rare, representing only 4% of gastrointestinal (GI) cancers. So, when it comes to bowel cancer, MRI not only determines the size and location of a tumour, but it also accurately distinguishes whether it is a benign or malignant growth.

A bowel MRI can tell the different types of cancer, such as adenocarcinomas, lymphomas, sarcoma, carcinoids, and gastrointestinal stromal tumours (GISTs) apart and identify metastases (i.e., secondary growth) originating from other organs. Given that it can visualise the bowel wall, nearby lymph nodes, and adjacent structures, a bowel cancer MRI result may show the severity or extent of cancer, allowing accurate staging and effective treatment planning.

Why have a small bowel MRI scan for bowel problems?

A small bowel MRI scan is a highly recommended test for investigating the cause of painful bowel symptoms for several reasons. First, its advanced technology offers excellent soft tissue contrast, making it easy to differentiate between normal and abnormal tissues or characterise suspicious masses based on their appearance. Also, it conducts a thorough assessment of the small intestine, including its functional aspects (such as movements and blood flow) and nearby structures to aid in the superior detection of abnormalities that aren't readily noticeable. It also shows extraintestinal manifestations (secondary findings outside the small intestine) of bowel diseases. 

In essence, an MRI small bowel scan delivers a comprehensive evaluation of a wide range of bowel problems. Moreover, it is non-invasive and considered safe for young people and pregnant women since it doesn’t involve exposure to ionising radiation, as with X-rays or CT scans.

 

Book your small bowel MRI scan today to check your bowel health and learn what’s causing your symptoms. Scan.com is the UK’s largest imaging network, offering access to over 150+ scanning centres nationwide. Browse our network, compare prices, and book the earliest time slot at a location near you in a matter of minutes and from the comfort of your home. No GP referral. No NHS waiting list. 

 

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