Overview

An MRI defecating proctogram is an examination that uses magnetic resonance imaging (MRI) to see how well your pelvic floor is working. It looks at the way your bottom (rectum) empties, and how the muscles of the pelvis and bladder move when you have a poo (open your bowels).

An MRI uses a powerful magnet to scan 3D images of your body, which help diagnose your health condition. There is no use of radiation or X-rays.

You can read more about MRI scans on the NHS website. 

During the examination, you’ll be given a small sodium phosphate enema. This is fluid that is inserted into your bottom to help clean your bowels.

We'll also insert a small amount of rectal jelly into your bottom. You'll be asked to push this out during the MRI scan. This is so we can see how the muscles in your pelvis and bladder move when you have a poo.

Benefits of having an MRI defecating proctogram

You might need an MRI defecating proctogram to find out what’s causing your symptoms, such as problems having a poo, or having a pee (emptying your bladder). Your doctor has referred you for this test to help with your diagnosis or treatment plan.

Risks of having an MRI defaecating proctogram

An MRI is a very safe procedure for most patients, and involves no ionising radiation.

The most common side effect from this type of enema is diarrhoea.

Very rare side effects (less than 1 out of 10,000 cases): 

• tummy (abdominal) pain
• bloating
• feeling sick (nausea)
• being sick (vomiting)
• anal itching
• blistering
• dehydration

If these symptoms continue, contact your GP or go to your nearest emergency department (A&E).

You'll be asked to complete and sign a safety questionnaire before your scan to make sure it's safe for you to be scanned.

If you have a pacemakers or any other surgical implants, such as a cochlear implant, you cannot have an MRI. 

Pregnancy

National safety guidelines recommend that we do not scan pregnant women unless the scan is clinically urgent. The doctor who refers you for the scan, along with the radiologist (X-ray specialist) will decide if you should have the scan.

Many people who are pregnant have had MRI scans with no reported problems. If you're pregnant and have referred for an MRI scan and would like more information, please contact us.

Breastfeeding

If you're breastfeeding, you should let us know before your appointment. The sodium phosphate enema is not suitable while breastfeeding. 

Other treatment options

On occasion, a standard defecating proctogram can be done instead. This is done in the fluoroscopy unit. This involves using a paste of barium contrast and oats (instead of the rectal jelly) and X-rays. The barium oats show up on the X-rays so that images can be taken while you are having a poo. It does not give as much information as an MRI defecating proctogram.

Giving your permission (consent)

We want to involve you in decisions about your care and treatment. If you decide to have the procedure or treatment, we will ask you to sign a consent form. This says that you understand what is involved and agree to have the treatment.

Read more about our consent process.

Preparing for the procedure

There is no specific preparation for an MRI defecating proctogram. You can eat and drink as normal. If you are taking any medicines, please continue to take them. 

You'll be asked to arrive 45 minutes before your scan. When you arrive, we'll ask you to change into a hospital gown. You’ll need to remove all metal objects and lock away any valuables in the locker provided.

We'll explain the procedure to you and you can ask us any questions. You’ll also be asked to complete an MRI safety questionnaire.

Sodium phosphate enema 

You’ll be given a small sodium phosphate enema 30 minutes before your scan. A nurse puts 100ml of the liquid into your bottom, or you can choose to do it yourself. The liquid will clean the lower part of your bowel. This might be uncomfortable, but should not be painful.

After the enema is given you'll need to lie on your side and wait for at least 10 minutes before going to the toilet. We understand that it might not be possible for you to hold it in, so this time is a guideline as each patient is different.

You might need to use the toilet to poo several times before your scan begins.  

During the scan

Once your rectum is empty you'll be taken into the scan room. You'll be asked to lie on the table on your side. We will insert 180ml (just over half a soft drink can) of rectal jelly into your bottom. You'll need to hold the jelly until you're given further instructions, this is usually for a few minutes.  

You'll then be asked to lie on your back, feet towards the scanner, flat on the bed, with your knees bent. If you’re not comfortable please tell the radiographer.

The radiographers will leave the room before the MRI begins. You'll hear them talk to you in the headphones. If you need their help at any time, you can raise your hand. The bed moves, feet first into the scanner so that pictures of your pelvis can be taken. The radiographers will be able to see you throughout the examination. 

You'll be given instructions to push out the jelly, like when you are having a poo. We might ask you to do this several times. If the jelly has not all come out, you'll be asked to go to the toilet to push out the jelly, and return to the scanner for more imaging. 

This may sound unpleasant, however as the lower part of your bowel has been cleaned you will only be pushing out clean jelly. 

The scan takes 10 to 20 minutes, depending on if you need the toilet and more scanning.

Pain during the procedure

You should not feel any pain during the examination.

Some people find that the enema can cause some discomfort. If you're concerned please tell the radiographer or nurse at the time of the examination.

After the procedure

After the scan, you can change back into your clothes and leave when you're ready. You can eat and drink as normal. 

The pictures taken during the scan are looked at by the radiologist who will produce a detailed report for the doctor who referred you.

If you feel unwell after the examination, or have any concerns, please contact your GP or the MRI department.

Follow-up appointments

The doctor who referred you will discuss the results with you and any treatment you may need.

You should already have an appointment with the team who referred you. If you do not, please contact them to arrange one.