Endometriosis is a condition in which tissue that normally lines the uterus grows outside the uterus and forms lesions. Like the normal lining of the uterus, these lesions swell with the menstrual cycle, but because they cannot exit the body with menstrual bleeding, they cause inflammation and pain.

Laparoscopic surgery is the standard method used to diagnose and treat endometriosis. However, imaging techniques such as magnetic resonance imaging (MRI) also can be used to assist the diagnosis of endometriosis. They also may help better plan the surgery.

How MRI works

MRI employs magnets that produce a strong magnetic field. The human body consists mostly of water molecules and other molecules that contain protons or positively charged atoms. Upon application of the magnetic field, these protons all align in the same direction. Short bursts of radio waves are then sent to specific areas in the body, which disturb the alignment of the protons. When the radio waves are turned off, the protons realign and thereby release energy, which is detected by the MRI sensors.

In different types of tissue in the body, protons realign at different speeds and produce distinct signals.

What can be seen in an MRI scan

MRI scanners are well-suited to visualize non-bony parts or soft tissues in the body. For example, muscles, ligaments, and tendons can be seen very clearly with MRI.

MRI mainly detects deep infiltrating endometriosis, which is seen in about 20 percent of women with the disease. It can detect endometriosis that forms cysts on the ovaries, lesions in the pelvic wall and on the bowel, the cul-de-sac (an extension of the peritoneal cavity between the posterior wall of the uterus and the rectum), and the bladder. Moreover, an MRI can detect adhesions (bonds) between nearby tissues.

MRI is more accurate than ultrasound, but also much more expensive. For this reason, the use of ultrasound is more common.

Additional information

MRI is a painless and safe procedure. It does not use damaging ionizing radiation, as in a CT scan and X-ray imaging.

People with claustrophobia may find it uncomfortable to have an MRI because the scanner is quite narrow. It also produces a loud banging noise. Earplugs or headphones are provided, but some patients might still find the procedure uncomfortable.

Because the procedure uses a strong magnetic field, people with metal implants, such as a pacemaker or artificial joints, cannot have an MRI scan. It also is not recommended during pregnancy.


Endometriosis News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.