The following list summarizes the types of imaging studies that are used to diagnose various diseases and injuries.
Arthrography is the process of creating an arthrogram. To perform this study, a dye is injected into a joint, before another imaging study is conducted, such as an X-ray, CT scan, or MRI. The injected dye enhances the image that is produced. This gives your caregiver more information about the soft tissue structures (cartilage, tendons, ligaments). The risks of this study include allergic reaction to the dye, infection, and becoming faint.
A bone scan gives your caregiver information about stress to the bone, or how your bones are healing (bone activity). A bone scan involves injecting a low dose of radioactive material, called a radioactive tracer, into your veins. A machine scans your body and observes bone activity, marked by how much of the tracer your bones pick up. Bones that pick up a lot of tracer indicate infection, fracture, arthritis, bruising, or increased stress. A bone scan may also indirectly show an injury to soft tissue (cartilage, tendons, ligaments). Bone scans are especially helpful when there is bone or joint pain, and x-rays come back as normal or inconclusive.
Single photon emission computed tomography (SPECT) is a more specific type of bone scan. It looks at different areas of the body in thin slices (like slicing a loaf of bread). This allows for more detail in each area.
Computed tomography (CT) scans are detailed imaging studies. They look at bone, and to some degree at soft tissues, with much more detail than plain radiographs. A CT scan takes a series of radiograph images of the body (like slices of bread). This allows your caregiver to view the images on multiple planes, such as side-to-side, top-to-bottom, or front-to-back. CT scans can show some soft tissue, but not as well as an MRI can. Your caregiver may also choose to perform an arthrogram CT, as discussed above.
Magnetic resonance imaging (MRI) is a type of imaging study that does not use radiation. MRI is a powerful tool, that allows your caregiver to view your soft tissue. MRIs use a large magnet to create an image of your cellular structures. Like a CT scan, MRI allows your caregiver to look at images on more than one plane.
Having an MRI involves lying very still for a long time, while the machine scans a specific area of your body. The space where you lie in the machine is often small, which may cause trouble if you have fear of enclosed spaces (claustrophobia). There are currently some open air MRIs, but the images they produce tend to be less clear. People with pacemakers, aneurysm clips in the brain, some artificial eye implants, and some bullet fragments in the body, are not able to have an MRI. People with plates, screws, and wires (orthopedic implants) in the body can have an MRI, but this may affect the quality of the study.
MRI may be done with injection of a dye-like material, to help evaluate structures within a joint.
Myelography is a technique used to look at the disks between the vertebrae in the spine, to detect herniated disks. Myelography involves injecting a contrast dye around the spinal cord. A CT scan or X-ray is then taken. The risks of myelography include headache, nausea, vomiting, and leg pain.
Plain radiographs are often referred to as X-rays. A radiograph is a useful test to diagnose injuries and conditions involving the bones and joints. A radiograph is a simple test, that is readily available and cost effective. Unfortunately, radiographs are poor at detecting problems in the soft tissue. Therefore, they are used mostly for detecting fractures, dislocations, bone tumors, and bone infections.
Radiographs take images in 2 dimensions. Because of this, multiple images may be taken of the same area, to provide your caregiver with more information.
Tomography is a specialized type of plain radiograph, in which the areas above and below an area of interest are blurred out. This allows your caregiver to look at an area in slices. The use of tomography is becoming less common, because of the use of CT scans and MRI.
Ultrasound machines use a radio wave to detect and create an image of the body's soft tissues. Unfortunately, ultrasound images can be difficult to interpret. They do not show the bones. For this reason, ultrasound is not often used in sports medicine.