Pelvis MRI scan

Definition

A pelvis MRI (magnetic resonance imaging) scan is an imaging test that uses a machine with powerful magnets and radio waves to create pictures of the area between the hip bones. This part of the body is called the pelvic area.

Structures inside and near the pelvis include the bladder, prostate and other male reproductive organs, female reproductive organs, lymph nodes, large bowel, small bowel, and pelvic bones.

An MRI does not use radiation. Single MRI images are called slices. The images are stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of images.

Alternative Names

MRI - pelvis; Pelvic MRI with prostate probe; Magnetic resonance imaging - pelvis

How the Test is Performed

You may be asked to wear a hospital gown or clothing without metal fasteners. Certain types of metal can cause inaccurate images.

You lie on your back on a narrow table. The table slides into the middle of the MRI machine.

Small devices, called coils, may be placed around your hip area. These devices help send and receive the radio waves. They also improve the quality of the images. If pictures of the prostate and rectum are needed, a small coil may be placed into your rectum. This coil must stay in place for about 30 minutes while the images are taken.

Some exams require a special dye, called contrast media. The dye is most often given before the test through a vein (IV) in your hand or forearm. The dye helps the radiologist see certain areas more clearly.

During the MRI, the person who operates the machine will watch you from another room. The test typically lasts 30 to 60 minutes, but may take longer.

How to Prepare for the Test

You may be asked not to eat or drink anything for 4 to 6 hours before the scan.

Tell your health care provider if you are afraid of close spaces (have claustrophobia). You may be given a medicine to help you relax and be less anxious. Or, your provider may suggest an open MRI, in which the machine is not as close to the body.

Before the test, tell your provider if you have:

• Brain aneurysm clips
• Artificial heart valves
• Heart defibrillator or pacemaker
• Inner ear (cochlear) implants
• Kidney disease or dialysis (you may not be able to receive contrast)
• Recently placed artificial joints
• Vascular stents
• Pain pumps
• Worked with sheet metal in the past (you may need tests to check for metal pieces in your eyes)

Because the MRI contains strong magnets, metal objects are not allowed into the room with the MRI scanner:

• Pens, pocket knives, and eyeglasses may fly across the room.
• Items such as jewelry, watches, credit cards, and hearing aids can be damaged.
• Pins, hairpins, metal zippers, and similar metallic items can distort the images.
• Removable dental work should be taken out just before the scan.

How the Test will Feel

An MRI exam causes no pain. If you have difficulty lying still or are very nervous, you may be given a medicine to relax you. Too much movement can blur MRI images and cause errors.

The table may be hard or cold, but you can request a blanket or pillow. The machine produces loud thumping and humming noises when turned on. You can wear ear plugs to help reduce the noise.

An intercom in the room allows you to speak to someone at any time. Some MRIs have televisions and special headphones that you can use to help the time pass.

There is no recovery time, unless you were given a medicine to relax. After an MRI scan, you can resume your normal diet, activity, and medicines.

Why the Test is Performed

This test may be done if a female has any of the following signs or symptoms:

• Abnormal vaginal bleeding
• A mass in the pelvis (felt during a pelvic exam or seen on another imaging test)
• Fibroids
• A pelvic mass that occurs during pregnancy
• Endometriosis (usually only done after ultrasound)
• Pain in the lower belly (abdominal) area
• Unexplained infertility (usually only done after ultrasound)
• Unexplained pelvic pain (usually only done after ultrasound)

This test may be done if a male has any of the following signs or symptoms:

• Lumps or swelling in the testicles or scrotum
• Undescended testicle (unable to be seen using ultrasound)
• Unexplained pelvic or lower abdominal pain
• Unexplained urination problems, including trouble starting or stopping urinating

A pelvic MRI may be done in both males and females who have:

• Abnormal findings on an x-ray of the pelvis
• Birth defects of the hips
• Injury or trauma to the hip area
• Unexplained hip pain

A pelvic MRI is also often done to see if certain cancers have spread to other areas of the body. This is called staging. Staging helps guide future treatment and follow-up. It gives you some idea of what to expect in the future. A pelvic MRI may be used to help stage cervical, uterine, bladder, rectal, prostate, and testicular cancers.

Normal Results

A normal result means your pelvic area appears normal.

What Abnormal Results Mean

Abnormal results in a woman may be due to:

• Adenomyosis of the uterus
• Bladder cancer
• Cervical cancer
• Colorectal cancer
• Congenital defect of the reproductive organs
• Endometrial cancer
• Endometriosis
• Ovarian cancer
• Ovarian growths
• Problem with the structure of the reproductive organs, such as the fallopian tubes
• Uterine fibroids

Abnormal results in a man may be due to:

• Bladder cancer
• Colorectal cancer
• Prostate cancer
• Testicular cancer

Abnormal results in both males and females may be due to:

• Avascular necrosis of the hip
• Birth defects of the hip joint
• Bone tumor
• Hip fracture
• Osteoarthritis
• Osteomyelitis

Talk to your provider if you have questions and concerns.

Risks

MRI contains no radiation. To date, no side effects from the magnetic fields and radio waves have been reported.

The most common type of contrast (dye) used is gadolinium. It is very safe. Allergic reactions to the substance rarely occur. But gadolinium can be harmful to people with kidney problems who require dialysis. If you have kidney problems, tell your provider before the test.

The strong magnetic fields created during an MRI can interfere with pacemakers and other implants. People with most cardiac pacemakers cannot have an MRI and should not enter an MRI area. Some newer pacemakers are made that are safe with MRI. You will need to confirm with your provider if your pacemaker is safe in an MRI.

Considerations

Tests that may be done instead of a pelvic MRI include:

• CT scan of the pelvic area
• Vaginal ultrasound (in women)
• X-ray of the pelvic area

A CT scan may be done in emergency cases, since it is faster and most often available in the emergency room.

References

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Kwak ES, Laifer-Narin SL, Hecht EM. Imaging of the female pelvis. In: Torigian DA, Ramchandani P, eds. Radiology Secrets Plus. 4th ed. Philadelphia, PA: Elsevier; 2017:chap 38.

Roth CG, Deshmukh S. MRI of the uterus, cervix, and vagina. In: Roth CG, Deshmukh S, eds. Fundamentals of Body MRI. 2nd ed. Philadelphia, PA: Elsevier; 2017:chap 9.