What is an MRI scan?
An MRI (Magnetic Resonance Imaging) scan is a safe, non-invasive test that provides detailed images of your internal organs and soft tissues using strong magnets and radio waves. Unlike CT scans or X-rays, MRI does not use radiation, making it a safe and highly effective way to assess bowel conditions.
MRI scans are particularly useful for examining the bowel, pelvic floor, and surrounding structures because they offer high contrast resolution, meaning they can show the different layers of the bowel wall and nearby tissues in great detail.
Why might you need an MRI scan?
Your doctor may recommend an MRI scan if you have bowel symptoms, ongoing pain, or need further assessment for a condition. MRI scans help with diagnosing, monitoring, and planning treatments for a range of bowel-related conditions.
Types of MRI scans for bowel investigations
MRI for small bowel (MR enterography/enteroclysis)
If you have been diagnosed with Crohn’s disease or other inflammatory bowel conditions, an MRI scan of the small bowel may be recommended to:
- Detect inflammation, strictures (narrowing), and fistulas
- Monitor your condition and how well your treatment is working
- Provide detailed images of the small intestine that a standard endoscopy cannot reach
For this scan, you may need to drink a special contrast liquid beforehand to highlight the small bowel in the images.
MRI for the large bowel (colon and rectum)
MRI is not the first choice for investigating large bowel conditions, as colonoscopy and CT colonography are usually preferred. However, your doctor may request an MRI if:
- You have suspected or confirmed rectal cancer, as MRI provides a detailed assessment of tumour size and spread
- You are unable to have a colonoscopy but need further investigation of polyps or masses
- You have ulcerative colitis or another form of chronic inflammation that needs close monitoring
- You have perianal Crohn’s disease, and the MRI can detect fistulas or abscesses
MRI for the rectum
If you have rectal cancer or another rectal condition, MRI is often the best test to assess:
- The size and depth of tumours
- Whether the cancer has spread beyond the rectal wall
- If lymph nodes or nearby organs are affected
MRI is more accurate than CT for rectal tumours and is a key tool in planning surgery or treatment.
MRI for the perineum
If you have pain, swelling, or infections in the perineal area, your doctor may recommend an MRI scan to:
- Identify fistulas, abscesses, or deep infections
- Detect inflammation, especially in people with Crohn’s disease
- Assess soft tissue changes that may need treatment
MRI for the pelvic floor (MR defaecography)
Your pelvic floor is a group of muscles that support your bowel, bladder, and reproductive organs. MRI scans can assess how well these muscles are working. This may be useful if you have:
- Pelvic organ prolapse
- Difficulty passing stool (obstructed defaecation syndrome)
- Pelvic floor muscle damage from childbirth
During the scan, images may be taken while you are resting and straining to see how your pelvic muscles function.
MRI for the anal region
If you have anal pain, lumps, or abnormal symptoms, an MRI scan can help detect:
- Anal cancer and assess how far it has spread
- Soft tissue changes that may not be visible on other scans
A CT scan may still be needed alongside an MRI to provide additional information.
How to prepare for your MRI scan
Most MRI scans do not require special preparation, but some things you may need to do include:
- Fasting – You may need to avoid food and drink for 4-6 hours before the scan, depending on the type of MRI
- Clothing – You will need to remove metal objects, such as jewellery, watches, and hearing aids
- Contrast dye – Some scans require an injection of contrast dye to improve image quality
- Bowel preparation – If you are having an MR enterography scan, you may need to drink a special liquid before the scan to highlight your small bowel
The radiology team will provide specific instructions before your appointment.
What happens during the scan?
- You will be asked to change into a hospital gown
- You will lie on a scanning table, which will move into the MRI machine
- The scanner makes loud tapping and buzzing noises, so you will be given earplugs or headphones
- The scan will last between 20 and 60 minutes, depending on the area being examined
- If contrast dye is needed, it will be injected through a small cannula in your arm
MRI scans are completely painless, but you must lie still to ensure clear images. If you are claustrophobic, let the radiographer know before your scan.
Are there any risks?
MRI is a very safe procedure, but there are a few things to keep in mind:
- If you have metal implants, pacemakers, or cochlear implants, you must tell the radiology team before the scan
- Mild allergic reactions to contrast dye are rare but possible
- If you have kidney disease, you may need an alternative imaging method if contrast dye is required
The radiology team will ensure the scan is safe for you before proceeding.
Why choose the Midlands Bowel Clinic?
- State-of-the-art MRI scanners, including 1.5T, 3T, and open MRI options
- Expert radiologists specialising in bowel and pelvic imaging
- Fast access to scans and results
- A comfortable and patient-centred experience
Contact us
If you need an MRI scan or have any questions, we’re here to help. Our team is here to help.
