Imaging tests can allow your doctor to see the structures inside your shoulders. The most common imaging tests to diagnose shoulder problems are:
- X-ray (radiography). A standard X-ray is a simple test in which an X-ray beam (a form of electromagnetic radiation) is passed through the shoulder to create a two-dimensional picture of the bones that form the joint. Your doctor can use X-rays to view:
- joint space. Narrowing of the space between the bones, which are normally covered by cartilage, can be a sign of arthritis and its severity.
- bone spurs. Bony overgrowths at the joint are a sign of osteoarthritis.
- fractures. Broken bones will show up on X-rays, however, small cracks in the bone may not.
In some cases a contrast dye is injected into the shoulder to enable the doctor to better see the joint on X-ray. This is called arthrography.
- Computerized axial tomography (CAT) scan. Also called a computed tomography (or CT) scan, this noninvasive test combines X-ray equipment with sophisticated computers to produce multiple images, which are combined to depict cross-sectional slices of internal structures. CT scans may be used to diagnose shoulder fractures that don't show up on X-ray. They also show soft tissues, such as cartilage, ligaments and muscles, more clearly than traditional X-rays, so they are more useful for diagnosing certain shoulder problems, including arthritis and soft tissue injuries.
- Magnetic resonance imaging (MRI). This procedure uses a strong magnet linked to a computer to create a picture of the internal structures in black and white and shades of gray. Because an MRI shows the soft tissues, as well as the bones, it is particularly useful for diagnosing injuries to the cartilage, tendons and ligaments, as well as areas of swelling.
- Bone scan. This technique can be used to view stress fractures caused by repetitive trauma. It involves injecting a small amount of radioactive material into the bloodstream. The material collects in the bones, particularly areas of new bone growth where fractures are healing, enabling doctors to see those areas with a scanner.