Skip to main content MRI is an important tool used in medicine to investigate a wide variety of illnesses, including endometriosis. Through the use of a very strong magnetic field and radiowaves, MRI is able to generate highly detailed images of the human body and underlying disease. It is a safe and non-invasive scan and does not involve any radiation.
MRI is complementary to other imaging modalities such as ultrasound in its ability to detail important changes within the abdomen and pelvis that can occur with endometriosis. It is typically used in cases where ultrasound has been technically challenging or if an internal ultrasound scan is not appropriate.
The long term damage caused by endometriosis varies widely between individuals and can be difficult to predict based on symptoms alone. The knowledge of these underlying changes from imaging scans including an MRI scan forms a critical part in both the diagnosis and development of an individualised treatment plan for people affected by this disease.
When might MRI be useful?
MRI and ultrasound are the most widely used imaging techniques for the diagnosis of endometriosis. Both types of scans are able to diagnose endometriosis with good accuracy. Because of the high cost and limited availability of MRI, typically ultrasound is utilised first. MRI is not recommended as the first imaging scan when endometriosis is suspected.
MRI is sometimes recommended when certain extra detail above what has been provided by the initial ultrasound is required. It may also be useful if a high quality ultrasound scan could not be achieved technically (e.g. in patients where an internal probe is not appropriate or not tolerated) or if the initial ultrasound was negative or inconclusive but a strong suspicion of endometriosis remains. Both scans should be complementary to each other and each has unique benefits.
MRI has been found to be particularly useful in the evaluation of any bowel or bladder endometriosis and in the depiction of small deposits of endometriosis in the pelvis or ovaries. In severe endometriosis, MRI can be of significant benefit to the surgeon in planning the exact type of surgery required and any extra resources needed.
How accurate is MRI in depicting changes of endometriosis?
MRI is one of the most accurate imaging studies available to diagnose deep pelvic endometriosis and the consequences of long-standing disease. At present it is not recommended in earlier stages of disease where MRI accuracy is lower. There are multiple features of disease that will be reviewed on a MRI scan by a radiologist (a medical specialist in diagnostic imaging) to determine the likelihood of the presence of endometriosis. Some of the features of endometriosis depicted with high accuracy on MRI include:
- Endometriosis plaque formation
- Endometriosis on the ovaries
- Extensive pelvic scarring from endometriosis
- Bowel involvement by endometriosis
- Abnormal fallopian tubes
What happens when you have an MRI?
MRI is a method of imaging which utilises a strong magnetic fields and radiowaves to generate images of any region of the human body. Unlike X-ray and CT scanning, MRI does not utilise ionising radiation. MRI technology is not believed to produce any long term ill effects, and has been studied and used extensively in practice since the 1980s. MRI is not appropriate for some individuals and this will be screened as part of the safety questionnaire at the MRI clinic prior to performing the MRI scan.
On the day of the procedure, you will be asked to change into a gown and to remove your watch and certain jewellery. Underpants and socks are worn and no internal probe is required. You will be positioned on the MRI bed and various foam pads will be used to make you comfortable. A lightweight device called a coil will be placed on your abdomen over the region being imaged. The MRI machine creates noise when scanning, so for comfort usually headphones or earplugs are worn. During the scan your body will be positioned inside the MRI tunnel.
Modern day MRI scanners are very wide and can accommodate individuals of all sizes. The wide diameter of the modern day tunnels is useful to reduce anxiety or claustrophobia whilst inside the scanner. In a very small number of patients your doctor may prescribe a light sedative if there is concern that you may not be able to remain still and calm for the scan.
An optimum MRI scan requires high quality images to diagnose disease, and the largest hindrance to good image quality is motion. You will be monitored at all times by the technicians (radiographers) undertaking the scan, who will advise you if you are making too many movements. To reduce the motion of your bowel, often an injection of a medication such as Buscopan will be provided immediately prior to the scan.
The entire scan will take on average 20 minutes.
Afterward, you will be able to change back into your clothes and leave the clinic. The images created will be processed by the radiographers and then sent to the radiologist for interpreting. The radiologist will carefully review all of the pictures and will in turn provide a report on your scan to the doctor who has referred you for the scan. This report will outline whether features of endometriosis have been identified, and your doctor will convey these results to you at your follow-up appointment.