A magnetic resonance imaging (MRI) scan uses magnets and radio waves to capture images inside your body without making a surgical incision. The scan allows your doctor to see the soft tissues of the body, such as muscles, without your bones obstructing the view.
While an MRI can be done on any part of your body, a pelvis MRI scan specifically helps your doctor to see the bones, organs, blood vessels, and other tissues in your pelvic region—the area between your hips that holds your reproductive organs. This helps your doctor inspect potential problems found in other imaging tests, such as X-rays; diagnose unexplained hip pain; investigate the spread of certain cancers; or better understand the conditions causing your symptoms.
An MRI does not use radiation, unlike X-rays and CT scans, so it is considered a safer alternative, especially for pregnant women.
Since your pelvic area holds your reproductive organs, your doctor may order the test for different reasons depending on if you are male or female.
A pelvis MRI scan is a useful test for both sexes if you have:
- birth defects
- injury or trauma in the pelvic area
- abnormal X-ray results
- pain in the lower abdominal or pelvic region
- unexplained difficulties urinating or defecating
- cancer in your reproductive organs, bladder, rectum, or urinary tract
For women, your doctor may order an pelvis MRI to further investigate:
- irregular vaginal bleeding
- lumps or masses in your pelvic area
- pain in your lower belly or pelvic area
For men, a pelvis MRI might look into conditions such as:
- an undescended testicle
- lumps in the scrotum or testicles, or swelling in that area
Your doctor will fully explain why he or she is ordering the test and what he or she will be looking for before you have your procedure.
Since the test does not use radiation, there are few risks from an MRI scan.
However, there are risks for those who have implants containing metal. The magnets used in an MRI can cause problems with pacemakers or cause implanted screws or pins to shift in the body. Be sure to tell your doctor if you have any of the following implants:
- artificial joints
- artificial heart valves
- metal clips from aneurysm surgery
- bullet or other metal fragments
One complication that can also arise is an allergic reaction to the contrast dye. The most common type of contrast dye is gadolinium. However, the Radiological Society of North America states that these allergic reactions are often mild and easily controlled by medication (RSNA, 2012). Women are advised not to breastfeed their children 24 to 48 hours after they have been given contrast dye.
If you are claustrophobic or have a hard time in enclosed spaces, you may feel uncomfortable while in the MRI machine. However, there is nothing to fear. Your doctor may prescribe antianxiety medication to help with your discomfort. In some cases, you can also be sedated during the process.
Before the test, tell your doctor if you have a pacemaker or any other type of metal implanted in your body. Depending on your type of pacemaker, your doctor may suggest another method for inspecting your pelvic area, such as a CT scan. Some pacemaker models can be reprogrammed before an MRI so they are not disrupted during the examination.
Also, as the MRI uses magnets, it can attract metals. Alert your doctor if you have any type of metal in your body from previous procedures or accidents. You will need to remove any metal from your body, including jewelry and body piercings, before the test. You will change into a hospital gown so that any metal on your clothing does not affect the test.
Some MRI examinations use contrast dye that is injected into the bloodstream through an IV line. This helps provide a clearer image of the blood vessels in that area. The dye—typically gadolinium—can sometimes cause an allergic reaction. Tell your doctor about any allergies you may have or if you’ve had an allergic reaction in the past.
In some cases, you will need to clear your bowels prior to the exam. This may require you to use laxatives or enemas. You also may need to fast for four to six hours before the exam. Women may need to have full bladders for this exam, depending on what their scan is investigating (Cedars-Sinai, 2011). Be sure to go over the necessary preparations with your doctor before your scan.
According to the Mayo Clinic, the magnetic field generated by the MRI temporarily aligns the water molecules in your body. Radio waves take these aligned particles and produce faint signals, which are recorded as images by the machine. (Mayo, 2010)
If your test requires the use of contrast dye, a nurse or doctor will inject it into your bloodstream through an IV line. You may need to wait some time for the dye to circulate through your body before beginning the test.
An MRI machine looks like a large metal and plastic doughnut with a bench that slowly glides you into the center of the opening. According to the National Institutes of Health, so long as you have followed your doctor’s instructions and removed all metal, you will be completely safe in and around the machine (NIH, 2011).
You will lie on your back on the table that slides into the machine. The technician may place small coils around your pelvic region to improve the quality of the scan images. One of the coils may need to go inside your rectum, if your prostate or rectum is the center of attention (NIH, 2011).
You may receive a pillow or blanket to make you more comfortable as you lay on the bench. The technician will control the movement of the bench using a remote control from another room. He or she will be able communicate with you over a microphone.
The machine may make some loud whirring and thumping noises as the images are being taken. Many hospitals offer earplugs, while others have televisions or headphones to help you pass the time.
As the pictures are being taken, the technician will ask you to hold your breath for a few seconds. You will not feel anything during the test as the magnets and radio frequencies—those similar to FM radios—cannot be felt.
A typical pelvic MRI lasts thirty to sixty minutes.
After your pelvic MRI, you are free to leave the hospital unless your doctor tells you otherwise. If you were given a sedative, you will need to wait to drive until the medication has fully worn off. Or, you can arrange for a ride home after the test.
If your MRI images were projected onto film, it might take a few hours for the film to develop. It will also take some time for your doctor to review the images and interpret the results. More modern machines display images on a computer, so your doctor may be able to view them quickly.
The initial results from an MRI scan may come within a few days, but your comprehensive results can take up to a week or more.
When the results are available, your doctor will call you in to review them and fully explain the images. He or she may want to order more tests to make a diagnosis or gather more information. If your doctor can make a diagnosis from the images, he or she may have you start on treatment, if necessary.