Can Endometriosis Show on an MRI?

The NHS describes endometriosis as a condition where cells similar to those in the lining of the womb grow in other parts of the body. Symptoms listed by the NHS include severe period pain that stops you doing your normal activities, heavy periods, pain in your lower tummy and back, pain when you poo or pee, pain during or after sex, and extreme tiredness.

The NHS also says it can take a long time to diagnose endometriosis, and you might need several different tests. Because MRI gives detailed pictures of the pelvis, many people wonder whether an MRI scan will give them an answer. The honest reply is: sometimes, for some types of endometriosis, but not on its own.

How endometriosis is usually diagnosed

According to the NHS, a GP will ask about your symptoms and whether any close relatives have had endometriosis, and may offer a physical examination. Further tests can include an ultrasound scan, an MRI scan and a laparoscopy, a procedure where a camera is passed through a small cut in your tummy. The NHS says a laparoscopy can confirm if you have endometriosis.

The NHS notes that endometriosis symptoms can be similar to other conditions, such as adenomyosis, fibroids, pelvic inflammatory disease and irritable bowel syndrome, which is part of why diagnosis can take time.

Ultrasound usually comes first

The NICE guideline on endometriosis (NG73) recommends considering a transvaginal ultrasound to investigate suspected endometriosis, even if an examination of the abdomen and pelvis is normal. NICE says ultrasound can help identify endometriomas (cysts on the ovaries) and deep endometriosis involving the bowel, bladder or ureter. If a transvaginal scan is not appropriate, NICE recommends considering a transabdominal ultrasound of the pelvis instead.

Ultrasound does not use radiation, and an internal scan uses a small probe placed in the vagina. Our guide to pelvic ultrasound explains what to expect, and our ultrasound vs MRI guide compares the two.

Where MRI fits in

NICE is clear on this point. It says not to use pelvic MRI as the primary investigation to diagnose endometriosis. Instead, NICE recommends considering pelvic MRI to assess the extent of deep endometriosis involving the bowel, bladder or ureter.

NICE also recommends that, for women with suspected deep endometriosis involving the bowel, bladder or ureter, a pelvic ultrasound or MRI should be considered before an operative laparoscopy. Put simply, NICE positions MRI as a way to map deep endometriosis, often ahead of surgery, rather than as the first test for whether endometriosis is there at all.

What a normal scan does and does not mean

This is the most important point for anyone hoping a scan will settle the question. NICE says not to exclude the possibility of endometriosis if the abdominal or pelvic examination, ultrasound or MRI are normal. It recommends considering laparoscopy to diagnose endometriosis in women with suspected endometriosis, even if the ultrasound was normal.

So a scan that shows deep endometriosis or an endometrioma is useful information, but a scan that shows nothing does not mean your symptoms are not real or that endometriosis has been ruled out. If your symptoms continue, keep talking to your GP or gynaecologist about next steps.

What happens during a pelvic MRI

The NHS says an MRI scan usually takes between 15 minutes and 1 hour, but can take longer. You lie inside the scanner, which makes loud bangs and clicks, so you will be given ear plugs or headphones. Some scans use an injection of contrast medium (dye) to show more detail.

Before the scan you will be asked about metal in your body, such as surgical clips or a pacemaker, and whether you are or may be pregnant. Our guides to what to expect at an MRI, MRI safety and implants and MRI and claustrophobia cover the practical side.

Having a pelvic MRI privately

MRI does not use ionising radiation, so IR(ME)R does not apply. Many private clinics accept self-referral, usually after their own safety screening, but each clinic sets its own policy. Our guide to private MRI without a GP referral explains more.

Because NICE does not recommend MRI as the first test for endometriosis, a private MRI is likely to be most useful when a GP or gynaecologist has asked for it, or when it is already part of a plan. Your scan will be reported by an appropriately qualified clinician, and the clinic will tell you how long its report takes. Share the report with whoever is managing your care.

Prices vary by clinic, region and whether contrast is used. FindScan shows each clinic's own listed price. You can see MRI clinics near you or compare ultrasound clinics, and send an enquiry to the one you choose.

When to see a GP or get urgent help

The NHS advises seeing a GP if you think you might have endometriosis, if your symptoms are affecting your everyday life, work and relationships, or if you have had treatment from a GP but your symptoms do not get better or get worse. Call 999 or go to A&E if you have a stomach ache that came on very suddenly or is severe, or if it hurts when you touch your stomach.