A shoulder computed tomography or CT scan creates cross-sectional images of the shoulder using specialized X-ray cameras. A shoulder CT scan can help doctors see the bones and soft tissues in the shoulder in order to detect abnormalities. The CT scan may also help identify tumors and blood clots.
A CT scan is also referred to as a computed axial tomography (CAT) scan. A CT scan can be performed with or without contrast dye. This contrast material helps your doctor analyze and identify important vessels and structures, and makes it possible to identify abnormalities that cannot be seen without the dye.
The most common reason a shoulder CT scan is performed is to evaluate the shoulder after an injury, such as to assess a fracture more clearly or to identify a suspected fracture. This could be a one-time injury or a recurring one, such as the shoulder repeatedly popping out of its socket or dislocating.
Your doctor may use a shoulder CT scan to:
- identify blood clots
- identify masses or tumors
- identify infections
- identify tears to muscles, tendons, or ligaments
- identify inflammation of the joint
- diagnose injuries following trauma, such as a dislocation or fracture
- make pre-surgery plans
- determine the course of treatment for your injury
Your doctor may simply order a shoulder CT scan to help identify problems with the shoulder joint, such as pain, stiffness, or clicking noises, especially when an MRI of the shoulder cannot be performed (for example, when a patient has a cardiac pacemaker).
A shoulder CT scan carries very few risks.
The contrast dye used in the procedure can cause an allergic reaction or kidney problems. This risk is higher if your kidneys have already been damaged by disease or infection. Newer dyes pose much less risk to the kidneys.
As with any X-ray, there is some exposure to radiation. The radiation levels used in an X-ray test are considered safe for adults, but not for a developing fetus. So, tell your doctor if you’re pregnant or believe you could be pregnant.
Because the test is noninvasive, preparation for a CT scan doesn’t require much effort on your part.
You’ll want to wear loose, comfortable clothing because you’ll be required to lie down on a table. You’ll also be instructed to remove any jewelry and other metallic items from your body.
A CT scan is performed in a hospital’s radiology department or a clinic that specializes in diagnostic procedures. Once you have removed your jewelry and are in a hospital gown, a CT technician will have you lie down on a bench.
If you’re using contrast dye, you’ll have an intravenous line placed. This involves inserting a needle into your arm so the contrast dye can be injected into your veins. Pain is minimal — no greater than when your blood is drawn.
Your technician may ask you to lie in a specific position during the test. They may use pillows or straps to ensure that you stay in the correct position long enough to get a quality image. You may also need to hold your breath during brief individual scans to prevent blurring of the images.
Your technician will move the table — via remote from a separate room — into the CT machine, which looks like a giant donut made of plastic and metal. The machine will rotate around you as the table moves back and forth through the hole.
After a round of scans, you may be required to wait while the technician reviews the images to ensure they are clear enough so that your doctor can read them correctly.
When the scans are complete, you’ll be able to change into your regular clothes and go about your day.
A typical CT scan takes between 30 to 45 minutes to complete.
Results from a shoulder CT scan typically take a day to process. Your doctor will schedule a follow-up appointment to discuss the results of your CT scan and tell you how to proceed, depending on the findings.