Why It Is Done

Magnetic resonance imaging (MRI) of the shoulder is done to:

• Check unexplained shoulder pain.
• Find problems in the shoulder, such as arthritis , bone tumors, worn-out cartilage, torn ligaments, torn tendons, or infection. An MRI can detect tears in the cartilage ( labrum ) in the shoulder. Labral tears often are caused by injury and can lead to shoulder pain.
• Find rotator cuff disorders, including tears and impingement .

MRI may also help diagnosis a bone fracture when X-rays and other tests are not clear. MRI is done more commonly than other tests to check for certain bone and joint problems.

How To Prepare

Before your MRI test, tell your doctor and the MRI technologist if you:

• Are allergic to any medicines. The contrast material used for MRI does not contain iodine. If you know that you are allergic to the contrast material used for the MRI, tell your doctor before having another test.
• Are or might be pregnant.
• Have metal screws in your shoulder from a past shoulder surgery.
• Have any metal implanted in your body. This helps your doctor know if the test is safe for you. Tell your doctor if you have:
  • Heart and blood vessel devices such as a coronary artery stent, pacemaker, ICD (implantable cardioverter-defibrillator), or metal heart valve.
  • Metal pins, clips, or metal parts in your body, including artificial limbs and dental work or braces.
  • Any other implanted medical device, such as a medicine infusion pump or a cochlear implant.
  • Cosmetic metal implants, such as in your ears, or tattooed eyeliner.
• Had recent surgery on a blood vessel. In some cases you may not be able to have the MRI test.
• Have an intrauterine device (IUD) in place. An IUD may prevent you from having the MRI test done.
• Become very nervous in confined spaces. You need to lie very still inside the MRI magnet, so you may need medicine to help you relax. Or you may be able to have the test done with open MRI equipment. It is not as confining as standard MRI machines.
• Have any other health conditions, such as kidney problems or sickle cell anemia, that may prevent you from having an MRI using contrast material.
• Wear any medicine patches. The MRI may cause a burn at the patch site.

You may need to arrange for someone to drive you home after the test, if you are given a medicine ( sedative ) to help you relax.

You may be asked to sign a consent form that says you understand the risks of the test and agree to have it done.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form .

How It Is Done

A magnetic resonance imaging (MRI) test is usually done by an MRI technologist. The resulting pictures are usually interpreted by a radiologist . But some other types of doctors, such as an orthopedic surgeon , can also interpret a shoulder MRI scan.

You will need to remove all metal objects (such as hearing aids, dentures, jewelry, watches, and hairpins) from your body because these objects may be attracted to the powerful magnet used for the test.

You will need to take off all or most of your clothes, depending on which area is examined (you may be allowed to keep on your underwear if it is not in the way). You will be given a gown to use during the test. If you are allowed to keep some of your clothes on, you should empty your pockets of any coins and cards (such as credit cards or ATM cards) with scanner strips on them because the MRI magnet may erase the information on the cards.

During the test

During the test, you will lie on your back on a table that is part of the MRI scanner . The table will slide into the space that contains the magnet. A device called a coil may be placed over or wrapped around the area to be scanned.

Some people feel nervous (claustrophobic) inside the MRI magnet. If feeling nervous keeps you from lying still, you can be given a medicine (sedative) to help you relax. Some MRI machines (called open MRI) are made so that the magnet does not enclose your entire body. Open MRI machines may be helpful if you are claustrophobic.

Inside the scanner, you will hear a fan and feel air moving. You may also hear tapping or snapping noises as the MRI scans are taken. You may be given earplugs or headphones with music to reduce the noise. It is very important to hold completely still while the scan is being done. You may be asked to hold your breath for short periods of time.

During the test, you may be alone in the scanner room. But the technologist will watch you through a window. You will be able to talk with the technologist through a two-way intercom.

If contrast material is needed, the technologist will usually put it in through an IV in your arm or hand. The injection may be given over 1 to 2 minutes.

Contrast material may be put directly into your shoulder joint by the radiologist. Your doctor will make your shoulder numb ( local anesthetic ) before putting in the contrast material. Then more MRI scans are done for this part of the test. This is called a magnetic resonance arthrogram.

An MRI test usually takes 30 to 60 minutes but can take as long as 2 hours.

How It Feels

You won't have pain from the magnetic field or radio waves used for the MRI test. The table you lie on may feel hard and the room may be cool. You may be tired or sore from lying in one position for a long time.

If a contrast material is used, you may feel some coolness when it is put into your IV. You may have a squishy feeling in your shoulder for 1 to 2 days from the material.

In rare cases, you may feel:

• A tingling feeling in the mouth if you have metal dental fillings.
• Warmth in the area being examined. This is normal. Tell the technologist if you have nausea, vomiting, headache, dizziness, pain, burning, or breathing problems.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Metal devices in your shoulder or chest from previous surgery. These can make the MRI pictures blurry and prevent your doctor from seeing what is wrong with your shoulder.
• Medical devices that use electronics, such as a pacemaker or medicine infusion pump. The MRI magnet may cause problems with these devices.
• If you are not able to remain still during the test.
• Obesity. A person who is very overweight may not fit into the opening of some standard MRI machines.

What To Think About

• Sometimes your MRI test results may be different than those from CT , ultrasound , or X-ray tests because the MRI scan is more specific.
• Other procedures, such as an arthrogram or arthroscopy, may be used to evaluate shoulder problems.
  • Arthrogram
  • Arthroscopy
• Open MRI machines are now made so that the magnet does not completely surround you. Open MRI is useful for people who are claustrophobic or obese. But these machines are not available everywhere. Also, these machines may not be able to do all the studies needed to check for problems.