If you’re experiencing difficulties passing bowel movements, or if you’re struggling with faecal incontinence or a prolapsed pelvic organ, your doctor may refer you for something called an MRI defecating proctogram scan. Undergoing this type of scan may feel daunting, but it can help your clinician get a much closer look at your pelvic floor and bowel, with the potential to vastly improve your treatment and outlook.
This guide explains what to expect during an MRI defecating proctogram, with step-by-step details to help you feel prepared and at ease.
What is an MRI Defecating Proctogram?
An MRI defecating proctogram (also known as MR defecography) is an advanced imaging technique using magnetic resonance imaging (MRI) that your doctor will use to check the function and structure of your rectum and pelvic floor during defecation - i.e. when you’re having a poo. But don't worry - you won’t be having an actual poo in public! Instead, your medical team will insert a special gel into your rectum, which they will ask you to pass during the MRI scan.
This non-invasive procedure gives your specialist detailed images of the region around the anus (anorectal), allowing them to see if any underlying conditions or problems are affecting your bowel movements, such as chronic constipation, faecal incontinence and pelvic organ prolapse.
The high-resolution images that the MRI defecating proctogram offers your medical team are particularly helpful for diagnosing disorders that affect bowel function. That’s because they can reveal problems with the pelvic floor muscles and the connective tissues that wouldn’t normally be visible using other imaging methods, such as a traditional X-ray.
Reasons You Might Need a Defecating Proctogram MRI Scan
You may be referred for an MRI defecating proctogram for one of several problems concerning your bowels, including:
Chronic Constipation
Constipation is defined as having infrequent bowel movements (fewer than three times a week), along with difficulty passing stools or straining to pass them. It can also cause the sensation of having incomplete bowel movements, where it feels like you haven’t emptied your bowels fully.
Your stools may be hard, dry, lumpy and difficult to pass, and they may be unusually large or small.
Your doctor will diagnose chronic constipation if you have been experiencing these symptoms for three months or more.
Faecal Incontinence
Faecal incontinence is the involuntary passage of faeces that can cause embarrassment and hygiene problems. It can have many causes, such as problems with the structure of the anus or the rectum, or both, and pelvic organ or rectal prolapse.
Pelvic Organ Prolapse
Pelvic organ prolapse is when one or more of your pelvic organs, such as your womb or vagina, slips out of position and moves downwards, possibly protruding from the vagina. It can feel very uncomfortable and can cause problems with passing urine and bowel movements.
Suspected Rectal Obstruction
A suspected rectal obstruction, also known as a rectal blockage or bowel obstruction, happens if something is blocking the normal passage of stools through the intestines and rectum. It can be a partial or complete blockage and can be caused by several factors, including compacted faeces, tumours, hernias, scar tissue or external objects.
Post-Surgical Evaluation
Certain types of surgery can affect defecation and bowel movements, including any surgery that involves the colon, rectum or pelvic areas. These include removing parts of the colon, having surgery for piles (haemorrhoids), and rectal cancer surgery. They may cause nerve damage, affect control of the sphincter, or narrow the ends of the bowel, all of which can cause bowel movement problems. Your doctor will want to assess how well the bowel works after surgery and whether you need treatment to help you pass stools more comfortably.
Pelvic Floor Dysfunction Symptoms
If you have pelvic floor dysfunction symptoms, such as faecal incontinence, chronic constipation, pelvic pain, pelvic organ or difficulties having sex, your doctor may recommend an MRI defecating proctogram to take a closer look at the pelvic floor muscles and tissues and how they work when you try to empty your bowels.
How to Prepare for an MRI Defecating Proctogram
Proper preparation for an MRI defecating proctogram can help ensure that your radiologist gets clear imaging, and it helps to make the procedure more comfortable for you, too. While the preparation process is usually pretty straightforward, it’s essential to follow any instructions your medical team provides. Here are some key steps and considerations to help you prepare for your scan.
Don’t Worry About Fasting, Unless You’re Told Otherwise
You wont normally need to avoid drinking or eating before your MRI, but sometimes it may be required, so be sure to read any guidelines your clinic gives you before your procedure takes place.
Empty Your Bladder Before the Procedure
The person carrying out the MRI (radiographer) may ask you to empty your bladder before the scan. This can help ease any discomfort during the procedure.
Wear Comfortable, Metal-Free Clothing
It’s important to wear clothing that’s easy to remove with no metal zips or buttons. Also, be sure to remove any hearing aids, jewellery, body piercings, hairclips or watches. MRI uses a strong magnet, so metal and electronic items can interfere with the imaging process or even cause burns.
Let Your Technician Know if You Have Any Implants or Devices
In most cases, MRI is safe for people with implants and devices. However, certain devices can cause problems depending on what types of implant or device they are, including:
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cochlear implants
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lips used for brain aneurysms
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metal coils in blood vessels
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older cardiac defibrillators and pacemakers
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vagal nerve stimulators
You should also let your radiologist know if you have an intrauterine device (IUD), if you think you may be pregnant, if you have any permanent eyeliner or tattoos, if you are wearing a medicine patch, or if you have an implanted pump, such as an insulin pump.
Complete Any Prescribed Bowel Preparation
A member of your MRI team may need to carry out an enema to clear out your bowels before the scan. This helps them to see the pelvic floor, rectum and surrounding structures more clearly during the procedure.
Avoid Using Laxatives Unless Instructed
Your doctor may prescribe laxatives to use before the procedure so you can clear out your bowels at home. Do not take any laxatives unless instructed to by your medical team.
What Happens During the Scan?
When you arrive at the clinic for your MRI you’ll be asked to change into a hospital gown and securely store any belongings. Your radiographer will explain the procedure to you, and you’ll have the chance to ask any questions.
Positioning in the MRI Scanner
At first, your radiographer will ask you to lie on your left side on the MRI table. A member of the MRI team will insert some gel into your rectum and ask you to turn onto your back for the rest of the scan. They’ll also place a special camera called a coil on your stomach.
Application of Rectal Contrast or Gel
Before the MRI scan starts, a member of the team will gently insert gel into your rectum using a small enema tip. The gel simulates the consistency of stool.
Imaging at Rest
The first part of the scan captures the structures of your pelvis while you are relaxed. Your radiographer will ask you to lie still as the MRI scanner creates the images.
Imaging While Squeezing
Next, your radiographer will ask you to ‘squeeze and lift,’ like a pelvic floor exercise. This helps show how well your pelvic muscles can hold the rectal gel in place.
Imaging While Straining
Finally, you will be asked to simulate a bowel movement while lying on the table. Although it may feel awkward, this step is crucial for assessing how your rectum empties. A towel will be placed underneath you to absorb any leakage during this phase.
Your radiographer will then ask you to ‘bear down and push,’ as though you are trying to pass a stool. This shows how your pelvic floor muscles behave under strain and whether there are any problems with how the bowel functions. You may be asked to repeat this up to six times, with each exercise lasting around 20 seconds.
Imaging During Simulated Bowel Movement
Finally, your radiographer will ask you to simulate a bowel movement while lying on the table. Although it may feel awkward or embarrassing, this step is crucial for assessing how well your rectum empties. You’ll have a towel placed underneath you to absorb any leakage.
How Long Does an MRI Defecating Proctogram Take?
An MRI defecating proctogram typically lasts around 30 minutes. However, you may be asked to arrive at the clinic around 60 minutes before the scan, so be sure to leave enough time in your day for the whole princess from start to finish. If you’re unsure, ask your medical team beforehand.
After the Scan
While the procedure is painless, some people may experience mild bloating or cramping due to the gel or contrast material inserted into the rectum. If you had a sedative before the scan, be sure to rest until the effect has worn off. You'll need someone to drive you home, too.
You should be able to return to your usual diet and activities after the procedure unless your doctor advises otherwise.
What Are the Benefits of an MRI Proctogram?
An MRI defecating proctogram can capture clear and detailed images of your pelvic floor and rectum, which are essential for diagnosing some of the conditions we’ve mentioned in this guide. Unlike traditional X-ray methods, MRI doesn't expose you to radiation, making it safer for repeated use. It also provides a detailed view of soft tissues, which will help your doctor identify conditions such as pelvic floor disorders.
MRI Proctogram vs. Traditional Defecography
An MRI proctogram has several advantages over traditional defecography. Traditional defecography provides static X-ray images that can only show the pelvic floor at rest and during defecation. It can’t capture the full range of pelvic floor motion as effectively as MRI.
MRI’s advanced imaging helps your medical team get a detailed look at how your pelvic floor moves and functions during key activities like squeezing, straining, and pushing out a simulated bowel movement. This gives them a better understanding of how all the muscles and structures work together and whether any potential problems lie.
MRI can reveal detailed images of soft tissues, which is essential for identifying small and subtle abnormalities, such as weakened walls of tissue that can lead to rectal bulging.
Lastly, MRI avoids exposing you to ionising radiation, making it a safer option, especially if you need multiple scans.
Are There Any Risks or Side Effects?
Yes, there are some risks and side effects to the MRI proctogram, but your clinician will be sure to discuss them with you before the scan. Here’s what to be aware of:
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Magnetic field risks: MRI’s magnetic field can interfere with some implants and devices, so be sure to let your radiographer know if you have any that you can’t physically remove yourself.
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Contrast agent reactions: A small number of people have allergic reactions to the contrast agent, and it can sometimes cause issues for people with kidney problems.
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Discomfort: You may feel mild pressure or discomfort during the scan from the rectal gel or your positioning.
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Dizziness or sensory effects: Some people feel a bit dizzy or experience sensory changes for a short period after the scan because of the magnetic fields.
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Anxiety or claustrophobia: The confined space of the MRI scanner can make some people feel anxious or claustrophobic. Let your radiographer know if this is the case for you, as they can help you feel more comfortable with a sedative if you need it.
How to Get an MRI Proctogram Scan
If you’re experiencing problems with your bowel movements, book a private MRI proctogram scan today to get answers. If you’re unsure whether the procedure is suitable, one of our expert clinicians is available for a personalised consultation. They can discuss your symptoms and concerns and help you decide what to do next.
It’s completely normal to feel a bit anxious or embarrassed about having an MRI proctogram, but rest assured that the team carrying out the scan will have done it plenty of times. Your team will help you feel comfortable and relaxed and take every step possible to ensure your privacy is respected. If you feel uncomfortable or anxious at any point, don’t hesitate to let your radiographer know - they are there to support you at every step.
Sources:
Constipation. (2024). https://cks.nice.org.uk/topics/constipation/
Defecating Proctogram MRI. (2021). https://www.whittington.nhs.uk/default.asp?c=42431
Faecal incontinence in adults. (2022). https://cks.nice.org.uk/topics/faecal-incontinence-in-adults/
Having an MRI Defecating Proctogram. (2024) https://www.cuh.nhs.uk/patient-information/mri-defaecating-proctogram/
MR Defecography. (2023). https://www.radiologyinfo.org/en/info/defecography-mri
Pelvic organ prolapse. (2022). https://www.rcog.org.uk/for-the-public/browse-our-patient-information/pelvic-organ-prolapse/
Urinary incontinence and pelvic organ prolapse in women: management. (2019). https://www.nice.org.uk/guidance/ng123
